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Ophiojagtus acklesi sp. nov. urn:lsid:zoobank.org:act: A51326C9-FAAE-4FFF-96BA-C8442F76BA0B Fig. 38: 5-7 Diagnosis Ophiacanthid with stout, thick, strongly curved LAPs generally with a high height/width ratio; outer surface devoid of ornamentation elements; no spurs on outer proximal and inner distal edges; ventral portion of LAPs long to extremely long, strongly protruding ventralwards and often with widened ventral tip; proximal edge commonly with proximalwards pointing protrusion; large, ear-shaped spine articulations composed of thick, continuous volute, freestanding on bulging distal portion of LAP and not bordered proximally by a ridge-like structure; broad, well defined ridge on the inner side of the LAPs, generally with dorso-proximalwards pointing dorsal part; tentacle notch large but poorly defined and generally shallow. Etymology Species named in honour of Texas-born actor Jensen Ackles; my wife urged me to do so. Type material Holotype GZG.INV.78814. Paratypes GZG.INV.78815 and GZG.INV.78816. Type locality and horizon Wizard Way, Texas, USA; echinoid marker bed of Smith & Rader (2009), latest Aptian, Early Cretaceous. Additional material GZG.INV.78817 (67 dissociated LAPs). Description Holotype GZG.INV.78814 is a dissociated, moderately large, proximal LAP; approximately twice higher than wide; of stout, massive and strongly curved aspect; dorsal edge slightly concave on account of the pointed dorso-proximal tip of the LAP strongly protruding towards arm midline; distal edge convex; proximal edge concave, with two closely spaced, pointed protrusions, ventral one of which larger; ventral portion rather narrow and very long, accounting for more than one-third of the total LAP height, with widened, conspicuously ventro-proximalwards pointing ventral tip; outer surface with finely meshed stereom, devoid of ornament elements; slightly more coarsely meshed stereom on ventral portion of LAP. Four large, nearly equi-distant, ear-shaped spine articulations freestanding on strongly bulging distal portion of LAP, and composed of a thick, continuous volute; slight dorsalward increase in size of spine articulations; gap between spine articulations and distal edge of LAP rather narrow. Inner side of LAP with well-defined, prominent, broad but very short, oblique ridge; dorsal tip of ridge strongly widened and ventro-proximalwards extending onto inner side of protrusions of proximal edge of LAP; ridge restricted to the centre of the inner side, no part of the ridge extending onto the ventral portion of the LAP; no spurs on the inner side of the distal edge of the LAP; inner side of the tentacle notch relatively large, very poorly defined, shallow, almost indiscernible. Single small perforation between tentacle notch and ventral tip of ridge. Paratype supplements and variation GZG.INV.78815 is a dissociated median to distal LAP; approximately 1.5 times higher than wide; very well in agreement with holotype; ventral portion accounting for almost half of the total LAP height; single, large, well-developed, round protrusion on proximal edge. Four spine articulations similar to those observed on holotype. Inner side of LAP very well in agreement with that of holotype; ridge slightly shorter. GZG.INV.78816 is a dissociated proximal LAP; ventral portion missing; single large, well-developed, rounded protrusion on proximal edge. Five spine articulations similar to those of holotype but with weaker dorsalward increase in size. Inner side similar to that of holotype. Remarks The highly distinctive combination of characters displayed by these LAPs unambiguously places them in the genus Ophiojagtus gen. nov. Confusion with other LAP types assigned to this genus is precluded by the presence of four to five spine articulations, in combination with a very long ventral portion and a very short ridge on the inner side not extending onto the ventral portion of the LAP but with a strongly widened dorsal tip projecting onto the inner side of the well-developed protrusion of the proximal LAP edge. Since this LAP type displays the diagnostic combination of characters of Ophiojagtus gen. nov. most clearly, it is chosen as the type species of the genus. Occurrence Latest Aptian of Texas., Published as part of Thuy, Ben, 2013, Temporary expansion to shelf depths rather than an onshore-offshore trend: the shallow-water rise and demise of the modern deep-sea brittle star family Ophiacanthidae (Echinodermata: Ophiuroidea), pp. 1-242 in European Journal of Taxonomy 48 on pages 219-220, DOI: 10.5852/ejt.2013.48, http://zenodo.org/record/3822836, {"references":["Smith A. B. & Rader W. I. 2009. Echinoid diversity, preservation potential and sequence stratigraphical cycles in the Glen Rose Formation (early Albian, Early Cretaceous), Texas, USA. Palaeobiodiversity and Palaeoenvironments 89 (1 - 2): 7 - 52. http: // dx. doi. org / 10.1007 / s 12549 - 009 - 0002 - 8"]}

Genus Ophiotoma Verrill, 1899 Type species Ophiotoma coriacea Lyman, 1883, by monotypy. Diagnosis LAPs devoid of constriction or strongly elevated or bulging distal portion; spine articulations free standing or in shallow notches of the slightly elevated distal edge; ventral portion of LAP very large, protruding ventro-proximalwards; tentacle notch large, inner side of tentacle notch in proximal LAPs at least as wide as one-third of the total ventral LAP edge width; outer surface commonly with vertical striation; no conspicuous spurs on outer proximal and inner distal edges; ridge on inner side of LAP generally with widened dorsal tip. Remarks The LAPs of extant species of Ophiotoma (Fig. 12: 1-3) are characterised by the lack of a constriction and of a bulging or strongly elevated distal portion, as well as a large, strongly protruding ventral portion bordering a large tentacle notch. The spine articulations are generally in shallow notches or depressions of the slightly elevated distal LAP edge, which differentiates them from the LAPs of Ophiologimus (see above). Superficial similarities exist to the LAPs of extant species of Ophiolimna Verrill, 1899 (see below). In these, however, the spine articulations are proximally slightly overlain by the coarse vertical striation of the outer surface and merged with the latter by a connecting ridge. The ophiacanthid fossil record includes only very few dissociated LAP types which convincingly match the diagnosis of Ophiotoma. Given their scarcity and limited currently known diversity, these fossil LAP types are here assigned to the extant genus Ophiotoma. The discovery of articulated specimens with the LAP types in question, however, are very likely to reveal differences in general skeletal morphology which imply distinction at the generic level. Irrespective of generic placement issues, the striking morphological similarities shared by the fossil LAPs and those of Ophiotoma strongly suggest close phylogenetic ties, which is the relevant aspect for the scope of the present study. The LAPs of Ophiotoma, especially the fossil ones, share an intriguing similarity with those assigned to extinct Dermocoma Hess, 1964 (see below), in particular on account of the strongly protruding ventral portion of the LAPs, the absence of a constriction and a bulging distal portion, the position of the spine articulations and the shape of the ridge on the inner side of the LAPs. The LAPs of Dermocoma tend to differ from those of Ophiotoma in displaying large and strongly protruding spurs on their outer proximal and inner distal edges. However, since both genera include species which deviate from this pattern, the latter cannot be taken as a rule. The only unambiguous character to distinguish the LAPs of Ophiotoma and Dermocoma is the size of the tentacle notch., Published as part of Thuy, Ben, 2013, Temporary expansion to shelf depths rather than an onshore-offshore trend: the shallow-water rise and demise of the modern deep-sea brittle star family Ophiacanthidae (Echinodermata: Ophiuroidea), pp. 1-242 in European Journal of Taxonomy 48 on pages 56-57, DOI: 10.5852/ejt.2013.48, http://zenodo.org/record/3822836, {"references":["Hess H. 1964. Die Ophiuren des englischen Jura. Eclogae geologicae Helvetiae 57: 756 - 801."]}

Dermocoma biformis (Hess, 1975) comb. nov. Fig. 27: 5-8 Ophiacantha ? biformis Hess, 1975a: 594, figs 10-12, pl. 1 fig. 6 [non pl. 1 fig. 5, which is not an ophiacanthid]. Ophiacantha ? biformis – Hess 1975b: 608, figs 8-9. Diagnosis Species of Dermocoma with very large LAPs displaying two well-defined spurs on outer proximal and inner distal edges; dorsal spur very large, prominent and strongly protruding, ventral spur smaller and less strongly protruding; fine, well-developed vertical striation on distal half of outer surface; up to five moderately large, equal-sized spine articulations in tight notches of distal portion of LAP; ridge on inner side large, relatively slender, with long, near-straight, almost vertical dorsal part slightly thickened at its centre. Material examined NHMB M11220, NHMB M11221 and 120 dissociated LAPs from the Günsberg Member, late Oxfordian of Guldental, Switzerland; GZG.INV.78690 and GZG.INV.78691 (137 dissociated LAPs) from sample S2a of Gale (2011) from the late Oxfordian of Savigna, France; GZG.INV.78692, GZG.INV.78693 (51 dissociated LAPs) from sample S2b of Gale (2011) from the late Oxfordian of Savigna, France; GZG. INV.78694 (36 dissociated LAPs) sample S1 of Gale (2011) from the late Oxfordian of Savigna, France; 14 dissociated LAPs from the Humeralis Member, late Oxfordian of Raedersdorf, France, original material of Hess (1975b); 33 dissociated LAPs from the Bifurcatus Zone, late Oxfordian of Guldental, Switzerland, the original material of Hess (1966); 11 dissociated LAPs from the Renggeri Member, early Oxfordian of Chapois, France, the original material of Hess (1965a). Description Very large, dissociated LAPs; proximal ones 1.5 times higher than wide, distal ones almost twice wider than high; dorsal edge slightly convex (proximal LAPs) to slightly concave (distal ones) as a result of a weak constriction; distal edge convex; proximal edge concave, with two spurs; dorsal spur very large, well-defined, oval, prominent and strongly protruding at least in proximal to median LAPs; ventral spur much smaller, less well-defined, weakly prominent and protruding; ventral fifth of LAPs strongly protruding ventro-proximalwards; outer surface with well-developed fine, vertical striation composed of slightly wavy, fine, weakly overlapping lamellae close to spine articulations, and replaced by very finely meshed stereom on proximal half of outer surface. Five (proximal LAPs) to three (distal ones) moderately large, ear-shaped spine articulations in relatively tight notches of the slightly elevated distal portion of the LAPs; ventral and dorsal lobes of spine articulations merged into continuous volute; ventral lobe with very weak and thin connection with distalwards projecting tips of outer surface separating notches; spine articulations proximally sharply separated by edge of notches; spine articulations nearly equal sized; dorsalward increase in size of gaps separating spine articulations; narrow gap between spine articulations and distal edge of LAP. Ventral edge of LAP with small, concave tentacle notch in all but the distalmost LAPs. Inner side of LAPs with large, conspicuous, sharply defined, prominent, moderately slender ridge; ventral part of ridge ventro-proximalwards bent, confluent with thickened ventral portion of LAP; dorsal part of ridge longer than ventral one, almost straight, slightly oblique with weakly thickened central part; ridge in distal LAPs short, oblique, with dorso-proximalwards pointing dorsal tip, widened ventral tip, and distally bordered by small round knob; inner side of distal edge with two moderately well-defined, oval spurs composed of densely meshed stereom; dorsal spur much larger than ventral one in proximal to median LAPs; inner side of tentacle notch small, deeply incised and sharply bordered laterally. Very shallow, poorly defined vertical furrow with few, minute perforations dorsally bordering tentacle notch and distally bordered by moderately well-defined, narrow and weakly prominent ridge; no perforations or furrow discernible in distal LAPs. Articulated arm fragments preserving median to proximal segments; ventral arm plates large, slightly longer than wide, polygonal, with straight to weakly concave distal edge, straight distalwards converging latero-distal edges; concave lateral and latero-proximal edges and a right to slightly acute proximal angle; LAPs in contact ventrally but not separating ventral arm plates; tentacle pores small, covered by at least one small, leaf-like tentacle scale; dorsal arm plates large, slightly longer than wide, widest distally separating LAPs, nearly trapezoid in outline, with convex distal edge, distalwards diverging, straight lateral edges and slightly convex proximal edge; dorsal arm plates with very fine transverse striation. Remarks Hess (1975a) originally described a set of dissociated LAPs from the Oxfordian of Switzerland as Ophiacantha ? biformis, the species name being chosen to reflect the fact that median and distal LAPs display a vertical striation which the proximal ones completely lack. However, as suggested by the observations of Thuy & Stöhr (2011), the type of ornament on the outer surface of the LAPs within one species is very unlikely to change fundamentally according to the position along the arm. Indeed, a careful re-examination of the type material has revealed that it included more than one type of LAPs and that a number of proximal LAPs, including the holotype, display the same vertical striation, although limited to a narrow band near the spine articulations, as observed on the median and distal LAPs. The original description and diagnosis of Ophiacantha ? biformis are based on at least two different types of LAPs, which is a prime example of why, for new species based on dissociated LAPs, the holotype and the paratypes should always be described individually (Thuy & Stöhr 2011). The LAP type corresponding to the holotype of Ophiacantha ? biformis can unambiguously be assigned to the genus Dermocoma on account of the shape, size and position of the spine articulations, the strongly protruding ventral portion of the LAPs and the shape of the ridge on the inner side. Closest similarities are shared with the LAPs of D. wrighti which, however, differ in displaying a dorsalward increase in size of the spine articulations, a slender ridge devoid of thickened parts, and a slightly less sharply defined dorsal spur on the outer proximal edge. New finds assignable to Dermocoma biformis comb.nov. from the Oxfordian of France include articulated arm fragments which complement the morphological data based on dissociated LAPs. The additional data on arm morphology are in agreement with the assignment to Dermocoma and furthermore suggest that the dorsal arm plate illustrated by Thuy (2005) and originally assigned to Ophiacantha ? toarcensis (see above), indeed, belongs to Dermocoma, most probably to D. faberi sp. nov. Occurrence Early Oxfordian of France; late Oxfordian of Switzerland and France., Published as part of Thuy, Ben, 2013, Temporary expansion to shelf depths rather than an onshore-offshore trend: the shallow-water rise and demise of the modern deep-sea brittle star family Ophiacanthidae (Echinodermata: Ophiuroidea), pp. 1-242 in European Journal of Taxonomy 48 on pages 151-153, DOI: 10.5852/ejt.2013.48, http://zenodo.org/record/3822836, {"references":["Hess H. 1975 a. Mikropalaontologische Untersuchungen an Ophiuren VI: Die Ophiuren aus den Gunsberg-Schichten (oberes Oxford) vom Guldental (Kt. Solothurn). Eclogae geologicae Helvetiae 68: 591 - 601.","Hess H. 1975 b. Mikropalaontologische Untersuchungen an Ophiuren VII: Die Ophiuren aus den Humeralis-Schichten (Ober-Oxford) von Raedersdorf (Ht-Rhin). Eclogae geologicae Helvetiae 68: 603 - 612.","Gale A. S. 2011. Asteroidea (Echinodermata) from the Oxfordian (Late Jurassic) of Savigna, Departement du Jura, France. Swiss Journal of Palaeontology 130 (1): 69 - 89. http: // dx. doi. org / 10.1007 / s 13358 - 010 - 0008 - x","Hess H. 1966. Mikropalaontologische Untersuchungen an Ophiuren V: Die Ophiuren aus dem Argovien (unteres Ober-Oxford) vom Guldental (Kt. Solothurn) und von Savigna (Dept. Jura). Eclogae geologicae Helvetiae 59: 1025 - 1063.","Hess H. 1965 a. Mikropalaontologische Untersuchungen an Ophiuren IV: Die Ophiuren aus dem Renggeri-Ton (Unter-Oxford) von Chapois (Jura) und Longecombe (Ain). Eclogae geologicae Helvetiae 58: 1059 - 1082.","Thuy B. & Stohr S. 2011. Lateral arm plate morphology in brittle stars (Echinodermata: Ophiuroidea): new perspectives for ophiuroid micropalaeontology and classification. Zootaxa 3013: 1 - 47.","Thuy B. 2005. Les Ophiures de l'Hettangien inferieur de Vance (B), Bereldange / Bridel et Bourglinster (L). In: Delsate D. (ed.) Biostratigraphie et Paleontologie de l'Hettangien en Belgique et au Grand- Duche de Luxembourg: 33 - 57. Memoirs of the Geological Survey of Belgium 51, Royal Belgian Institute of Natural Sciences, Brussels."]}

Ishidacantha trispinosa (Hess, 1965) comb. nov. Fig. 31: 5-6 p.p. Ophiopholis? trispinosa Hess, 1965a: 1075 , figs 36-37 [non figs 16, 38-41, referable to Lapidaster etteri gen. et sp. nov.] Diagnosis Species of Ishidacantha gen. nov. with large LAPs displaying coarsely meshed stereom on the outer surface with a very narrow band of poorly developed vertical striation near spine articulations; two moderately well-defined, horizontally elongate spurs on outer proximal and inner distal edges in proximal to median LAPs, dorsal one of which protruding; three large spine articulations in all LAPs, with continuous volute and strong dorsalward increase in size; inner side of proximal LAPs with two round, slightly oblique knobs in vertical row connected by poorly defined, irregular, slender, weakly prominent vertical ridge in proximal half, and short, near-vertical ridge in distal half; tentacle notch large. Material examined NHMB M11222, NHMB M11223; 5 dissociated LAPs from the Renggeri Member, early Oxfordian of Longecombe, France, the type material of Hess (1965a). Description Large dissociated LAPs; proximal ones almost twice wider than high, distal ones slightly more than twice wider than high; dorsal edge strongly concave as a result of a well-developed constriction; distal edge convex with a conspicuous, pointed protrusion in dorsal half of distal edge, best developed in proximal LAPs; proximal edge irregularly undulose, in proximal to median LAPs with two moderately welldeveloped, prominent, protruding, horizontally elongate, ridge-like spurs, dorsal one of which larger than ventral one; spurs almost indiscernible in distal LAPs; ventro-distal tip of LAPs strongly protruding ventralwards, tongue shaped; ventro-proximal tip of LAP strongly oblique; ventral half to third of LAP strongly protruding ventro-proximalwards, large, wide; outer surface of LAPs with coarsely meshed stereom, replaced by finely meshed stereom in narrow band along proximal edge of LAP; trabeculae of coarsely meshed stereom merged into poorly developed vertical striation in very narrow band near spine articulations in proximal LAPs. Three large, ear-shaped spine articulations freestanding on strongly elevated distal portion in all LAPs; ventral and dorsal lobes of spine articulations merged into continuous volute; spine articulations not sharply bordered proximally; very strong dorsalward increase in size of spine articulations; weaker dorsalward increase in size of gaps separating spine articulations; gap between spine articulations and distal edge of LAP almost as wide as one spine articulation. Ventral edge of LAPs nearly straight, except for large, conspicuous, very deeply incised almost semi-circular tentacle notch. Inner side of LAPs with two sharply defined, prominent ridge-like structures, proximal one separated into two, round, oblique knobs arranged in vertical row and connected by very poorly defined, narrow, weakly prominent irregular ridge; distal ridge-like structure consisting of single vertical, slightly oblique ridge in proximal to median LAPs, and of a small, round knob in distal LAPs; inner side of distal edge of proximal to median LAPs with two well-defined, prominent, horizontally elongate spurs composed of more densely meshed stereom, dorsal one of which slightly larger and protruding; spurs very poorly defined in distal LAPs; inner side of tentacle notch very large, widely encompassed by non-thickened ventral portion of LAPs. No perforations or furrow discernible. Remarks Hess (1965a) described Ophiopholis ? trispinosa Hess, 1965 on the basis of dissociated LAPs and articulated arm fragments from the Oxfordian of France, which are here shown to belong to two different species. The smaller LAPs and the articulated arm fragments are assignable to Lapidaster gen. nov., a probably close relative of extant large-pored Ophiologimus (see above). Most of the larger LAPs, including the holotype, are here demonstrated to belong to the new small-pored ophiacanthid genus Ishidacantha gen. nov. Among the LAP types assigned to this genus, the above-mentioned ones are unique in displaying three large spine articulations with a strong dorsalward increase in size, a coarsely meshed stereom with a very poorly developed vertical striation, and a proximal ridge on the inner side separated into a ventral and a dorsal knob. Thus, they are described here as a new species which displays the highly distinctive characters of the new genus best and is therefore selected as the type species of Ishidacantha gen. nov. Occurrence Early Oxfordian of France., Published as part of Thuy, Ben, 2013, Temporary expansion to shelf depths rather than an onshore-offshore trend: the shallow-water rise and demise of the modern deep-sea brittle star family Ophiacanthidae (Echinodermata: Ophiuroidea), pp. 1-242 in European Journal of Taxonomy 48 on pages 176-177, DOI: 10.5852/ejt.2013.48, http://zenodo.org/record/3822836, {"references":["Hess H. 1965 a. Mikropalaontologische Untersuchungen an Ophiuren IV: Die Ophiuren aus dem Renggeri-Ton (Unter-Oxford) von Chapois (Jura) und Longecombe (Ain). Eclogae geologicae Helvetiae 58: 1059 - 1082."]}

Genus Dermocoma Hess, 1964 Type species Dermocoma wrighti Hess, 1964, by original designation. Diagnosis Ophiacanthid with LAPs commonly displaying a fine vertical striation on their outer surface; welldeveloped spurs on the inner distal and, in some cases to a lesser extent, outer proximal edge; ventral portion of LAP strongly protruding ventro-proximalwards; up to six moderately large, ear-shaped spine articulations with continuous volute in notches of elevated distal portion of LAP; ridge on inner side of LAPs simple, continuous, generally slender, devoid of sharp kinks or conspicuously thickened parts; tentacle notch small to moderately large. Remarks Dermocoma was introduced by Hess (1964) on the basis of articulated specimens from the Middle Jurassic of Great Britain which were all assigned to the type, and at that time only known, species D. wrighti Hess, 1964. While the higher taxonomic position of Dermocoma was initially left open (Hess 1964), it was later used as type taxon for the introduction of the extinct family Dermocomidae Hess, 1972 (Hess 1972a). Thuy & Meyer (2013), however, showed it to be unambiguously assignable to the Ophiacanthidae. Since the original description of Dermocoma wrighti provided only few data on LAP morphology, a reexamination of the type specimens was called for in order to work out a comprehensive LAP morphology including as many characters as possible. Dermocoma and its sister genus Alternacantha share basically similar LAP morphologies, as already noted above. While the median and distal LAPs of both genera may be almost indistinguishable, the proximal LAPs allow for an unambiguous distinction. In fact, in the proximal LAPs of Dermocoma the position of the dorsalmost spine articulation never alternates, the distal portion of the LAPs is less strongly elevated and the notches of the spine articulations are generally deeper. As in Alternacantha, however, distinction of species within Dermocoma on the basis of dissociated LAPs can be a major challenge with differences occasionally found in the finest details only. The LAPs of Dermocoma can be easily distinguished from those of other ophiacanthids on account of the position of the spine articulations, the ventro-proximally protruding ventral part, and the simple ridge on the inner side devoid of sharp kinks and conspicuously widened parts. The LAPs assignable to Dermacantha gen. nov. (see below) share the greatest similarities with those of Dermocoma, differing only in having generally smaller spine articulations, a discontinuous volute of the spine articulations and a generally smaller height/width ratio. However, the similarities are so striking that Dermocoma and Dermacantha. gen. nov. are most probably closely related. Many of the previously known Jurassic ophiacanthid records based exclusively on dissociated LAPs have turned out to be assignable to Dermocoma. Together with the new records described in the present study, Dermocoma is among the most speciose and most widely distributed ophiacanthids in Mesozoic shallow-water deposits. Scattered records from a deep-shelf to upper slope setting, however, suggests that the genus was also present in deeper settings. The closest extant relative Ophiocopa spatula, sister to the Dermocoma - Alternacantha clade (see above), inhabits upper to middle bathyal depths (279-965 m) of the Pacific (O’Hara & Stöhr 2006)., Published as part of Thuy, Ben, 2013, Temporary expansion to shelf depths rather than an onshore-offshore trend: the shallow-water rise and demise of the modern deep-sea brittle star family Ophiacanthidae (Echinodermata: Ophiuroidea), pp. 1-242 in European Journal of Taxonomy 48 on pages 137-138, DOI: 10.5852/ejt.2013.48, http://zenodo.org/record/3822836, {"references":["Hess H. 1964. Die Ophiuren des englischen Jura. Eclogae geologicae Helvetiae 57: 756 - 801.","Hess H. 1972 a. Eine Echinodermenfauna aus dem mittleren Dogger des Aargauer Juras. Schweizerische Palaontologische Abhandlungen 92, Birkhauser, Basel.","Thuy B. & Meyer C. A. 2013. The pitfalls of extrapolating present-day depth ranges to fossil communities: new insights from brittle stars (Echinodermata: Ophiuroidea) from the Middle Jurassic of Switzerland. Swiss Journal of Palaeontology 132 (1): 5 - 21. http: // dx. doi. org / 10.1007 / s 13358 - 012 - 0048 - 5","O'Hara T. D. & Stohr S. 2006. Deep water Ophiuroidea (Echinodermata) of New Caledonia: Ophiacanthidae and Hemieuryalidae. In: Richer de Forges B. & Justine J. - L. (eds) Tropical Deep- Sea Benthos 24: 33 - 141. Memoires du Museum national d'Histoire naturelle 193, Museum national d'Histoire naturelle, Paris."]}

Lapidaster caeloscopus sp. nov. urn:lsid:zoobank.org:act: C670AEE6-65DA-49F5-B098-A8E1E372063A Fig. 7: 1-3 Diagnosis Species of Lapidaster with small, elongate LAPs of trapezoid outline, well-developed constriction and strongly enlarged dorsalmost spine articulation pointing dorsally. Etymology Name composed of caelum, Latin for “sky”, and scopus, Latin for “target”, in reference to the large, dorsally pointing, or “skygazing”, dorsalmost arm spine articulation in this species. Type material Holotype NHMW 2012/0137/0005. Paratypes NHMW 2012/0137/0006 and NHMW 2012/0137/0007. Type locality and horizon Glasenbach Gorge, Austria; Hauptknollenbrekzie, late Sinemurian to early Pliensbachian, Early Jurassic. Additional material NHMW 2012 /0137/0008 (12 dissociated LAPs). Description Holotype NHMW 2012 /0137/0005 is a dissociated, very small, proximal LAP, somewhat wider than high, of irregularly rectangular to trapezoid outline, with slightly concave dorsal edge as a result of a weak constriction; slightly concave distal edge; ventral fifth of LAP protruding ventro-proximalwards; ventrodistal tip of LAP very large, tongue shaped, strongly protruding ventro-distalwards; proximal edge of LAP almost straight to slightly concave, except for sharp kink in ventral quarter; the latter ventrally bordered by well-defined, elongate, lens-shaped and strongly prominent spur; outer surface with finely to moderately coarsely meshed stereom, with trabeculae not merged into vertical striation. Three earshaped spine articulations; conspicuously wide gap between spine articulations and distal edge of LAP; very strong dorsalward increase in size of spine articulations; dorsalmost spine articulation more than twice larger than ventralmost one, conspicuously pointing dorsalwards; dorsal and ventral lobes of spine articulations forming continuous volute; dorsal gap between spine articulations slightly larger than ventral one. Ventral edge of LAP with very large, concave tentacle notch. Inner side of LAP unfortunately partially obscured by sediment; ridge discernible, well defined, prominent, nearly straight to slightly bent, narrow, small and conspicuously short, hardly reaching horizontal midline of LAP, ventral tip of ridge well defined, not merged with slightly thickened ventral part of LAP; inner side of ventro-distal tip of LAP thickened into large, prominent, elongate and slightly protruding spur composed of dense stereom. Inner side of large tentacle notch obscured by sediment; presence of possible perforations on inner side indeterminable. Paratype supplements and variation NHMW 2012 /0137/0006 is a dissociated median LAP, approximately twice wider than high, of trapezoid outline; ventro-distal tip of LAP very large and strongly protruding; dorsal edge clearly concave as a result of the constricted outer surface; distal edge oblique, straight to slightly convex; dorsal four-fifths of proximal edge evenly convex; ventral fifth of proximal edge separated from the latter by sharp kink, ventrally bordered by moderately well-defined, prominent, elongate spur. Three spine articulations; dorsalward increase in size much weaker than in holotype; dorsalmost spine articulation slightly larger than remaining two, pointing dorsalwards; conspicuously wide gap between row of spine articulations and distal edge of LAP, as in holotype. Ventral edge of LAP with very large, gently concave tentacle notch. Inner side of LAP largely obscured by sediment; ridge similarly short as in holotype; inner side of ventro-distal tip of LAP with large, oval, strongly prominent spur composed of dense stereom. NHMW 2012 /0137/0007 is a dissociated distal LAP, more than twice wider than high, with strongly concave dorsal edge indicating a strong constriction; proximal edge undulose, with central convex part and ventral quarter sharply separated by kink; the latter bordered by relatively large, yet poorly defined, elongate, prominent spur. Two spine articulations, one near the ventral edge of the LAP, the second in the middle of the LAP, slightly larger than the ventral one. Ventral edge of LAP almost straight, except for large, yet only weakly concave tentacle notch. Inner side with very small, short, knob-like, prominent and well-defined ridge, widest ventrally and not merged with ventral part of LAP. Remarks The very small, dissociated LAPs of Lapidaster caeloscopus sp. nov. are unique in displaying a strongly enlarged dorsalmost spine articulation which points dorsally. The irregular trapezoid outline of the LAPs, as well as the very short ridge on the inner side, are further characters which clearly set the LAPs of L. caeloscopus sp. nov. apart from any other known type of LAPs. Greatest similarities are shared with the LAPs of Lapidaster lukenederi sp. nov. (see below) from the Valanginian of Austria, especially on account of the constriction, the rather thin plate architecture, the small size, and the height/width ratio of the proximal LAPs, which is indicative of elongated arm segments, a typically paedomorphic character (Stöhr 2005). In contrast, similarities to the distal LAPs of Reitneracantha dissidens sp. nov., which occur in the same samples, are merely superficial and limited to the enlarged dorsally pointing spine articulations found in both species. Almost all other characters, in particular the development of the tentacle notch, the outer surface ornamentation and the morphology of the spine articulations clearly differ in both species. Assignment to Lapidaster gen. nov. is suggested here on account of the general Ophiologimus -like LAP morphology (very large tentacle notch, ventro-proximalwards protruding ventral portion of LAP, strongly protruding ventro-distal tip of LAP, spine articulations neither sunken in depressions nor positioned on strongly elevated ridge), combined with the presence of a well-developed spur on the outer proximal and inner distal edges of the LAP. Occurrence Late Sinemurian to early Pliensbachian of Austria., Published as part of Thuy, Ben, 2013, Temporary expansion to shelf depths rather than an onshore-offshore trend: the shallow-water rise and demise of the modern deep-sea brittle star family Ophiacanthidae (Echinodermata: Ophiuroidea), pp. 1-242 in European Journal of Taxonomy 48 on pages 28-30, DOI: 10.5852/ejt.2013.48, http://zenodo.org/record/3822836, {"references":["Kutscher M. & Villier L. 2003. Ophiuroid remains from the Toarcian of Sainte-Verge (Deux-Sevres, France): paleobiological perspectives. Geobios 36 (2): 179 - 194. http: // dx. doi. org / 10.1016 / S 0016 - 6995 (03) 00005 - 6","Stohr S. 2005. Who's who among baby brittle stars (Echinodermata, Ophiuroidea): postmetamorphic development of some North Atlantic forms. Zoological Journal of the Linnean Society 143 (4): 543 - 576. http: // dx. doi. org / 10.1111 / j. 1096 - 3642.2005.00155. x"]}

Genus Sabinacantha gen. nov. urn:lsid:zoobank.org:act: DBFBC938-27CE-42A1-932C-F397C289B2E7 Type and sole known species Sabinacantha archetypa sp. nov. Diagnosis Ophiacanthid with moderately large LAPs of thick, massive and rounded aspect; single poorly to moderately well-defined, protruding spur on outer proximal edge paralleled by large, round, weakly prominent area of more densely meshed stereom on inner side of distal LAP edge; outer surface with coarse, irregular striation; three small, ear-shaped, oval, horizontally elongate spine articulations tightly grouped on weakly elevated ventral third to half of distal edge of LAP; dorsalward decrease in size of spine articulations; inner side of LAPs with well-defined, uniformly prominent, short, broad ridge with widened, round dorsal tip; inner side of tentacle notch small. Etymology Genus named in honour of my friend and colleague Sabine Stöhr, who has guided me when I took my very first steps in ophiuroid research; from Acantha, a nymph in Greek mythology whose name literally translates to “thorny”; gender feminine. Remarks Among the most unusual LAP types of extant ophiacanthids is that of Ophiohamus nanus O’Hara & Stöhr, 2006 (Fig. 36: 4-5). In this small-sized species, the LAPs appear atypically massive and rounded for an ophiacanthid. The most striking feature, however, are the four small, oval spine articulations with separated dorsal and ventral lobes, and grouped in the ventral half of weakly elevated distal edge. This combination of characters is highly distinctive and not found in any other currently known ophiacanthid LAP type, except for a remarkable extinct one from the Kimmeridgian of Germany, recorded herein. These fossil LAPs are much larger and thicker that those of Ophiohamus nanus but nevertheless display the highly characteristic rounded aspect and the small, oval spine articulations with the discontinuous volute, tightly grouped in ventral half of weakly elevated distal edge. Other close similarities are seen in the shape of the ridge on the inner side, although in the fossil LAPs it is better defined and uniformly prominent. Other minor differences pertain to the presence of a single, well-developed spur on the outer proximal and inner distal edges in the fossil LAPs, and the outer surface ornament which, in the fossil LAPs, consists of a coarse, highly irregular vertical striation, generally best defined close to the spine articulations. These close similarities in LAP morphology strongly suggest that the fossil LAP type in question and Ophiohamus nanus share strong phylogenetic ties, most probably forming a single lineage. The fossil LAPs probably are not congeneric with the latter, on account of the minor, yet significant, differences including the size of the LAPs, the number of the spine articulations, the development of the ridge on the inner side, and the outer surface ornament. A new genus, Sabinacantha gen. nov., is thus introduced here to accommodate these Ophiohamus -like fossil LAPs. There is, indeed, a close resemblance with the LAPs of extant Ophiochondrus convolutus Lyman, 1869, which is closely related to Ophiohamus nanus in the revised phylogenetic analysis presented herein, especially on account of the massive, rounded aspect of the LAPs, the weakly elevated distal edge of the LAPs, the small, oval, horizontally elongate spine articulations with separated dorsal and ventral lobes, the dorsalward decrease in size of the spine articulations, and even the shape of the ridge on the inner side. These astonishing similarities are perfectly in line with the observation by Thuy & Stöhr (2011) that the closest similarities in LAPs are to be found in more closely related ophiuroid taxa., Published as part of Thuy, Ben, 2013, Temporary expansion to shelf depths rather than an onshore-offshore trend: the shallow-water rise and demise of the modern deep-sea brittle star family Ophiacanthidae (Echinodermata: Ophiuroidea), pp. 1-242 in European Journal of Taxonomy 48 on pages 206-207, DOI: 10.5852/ejt.2013.48, http://zenodo.org/record/3822836, {"references":["O'Hara T. D. & Stohr S. 2006. Deep water Ophiuroidea (Echinodermata) of New Caledonia: Ophiacanthidae and Hemieuryalidae. In: Richer de Forges B. & Justine J. - L. (eds) Tropical Deep- Sea Benthos 24: 33 - 141. Memoires du Museum national d'Histoire naturelle 193, Museum national d'Histoire naturelle, Paris.","Thuy B. & Stohr S. 2011. Lateral arm plate morphology in brittle stars (Echinodermata: Ophiuroidea): new perspectives for ophiuroid micropalaeontology and classification. Zootaxa 3013: 1 - 47."]}

Genus Reitneracantha gen. nov. urn:lsid:zoobank.org:act: 3BFFDD52-C9E7-450B-9001-E09134B80477 Type, and only known, species Reitneracantha dissidens sp. nov. Diagnosis Ophiacanthid with moderately large LAPs devoid of conspicuous outer surface ornament or spurs on the outer proximal edge; up to five large to very large, ear-shaped spine articulations freestanding on the strongly elevated distal third or half of the LAP; proximal edge of the spine articulation irregularly corrugated; dorsal lobe of the spine articulations vertically elongate, much larger than ventral one; dorsalmost spine articulation invariably largest, conspicuously dorsalwards pointing, in proximal LAPs well below dorsal edge of LAP; ridge on inner side relatively short with widened dorsal tip; tentacle notch small, well defined laterally, semi circular. Etymology Genus named in honour of my friend and colleague Joachim Reitner, for his generous support and the delightfully shared delicacies and wines; from Acantha, a nymph in Greek mythology whose name literally translates to “thorny”; gender feminine. Remarks A very unusual type of dissociated LAPs was recovered from Early Jurassic deep-sea sediments of Austria. The presence of large, ear-shaped spine articulations with a sigmoidal fold, combined with the absence of a single large perforation on the inner side, clearly place these in the Ophacanthidae. Within this family, such LAPs are close to those of extant Ophiocamax. The most important similarities include the position of the spine articulations on the strongly elevated distal third or half of the LAP, the central notch in the dorsal lobe of the spine articulations, the strong dorsalward increase in size of the spine articulations, the conspicuously dorsalwards pointing dorsalmost spine articulation well below the dorsal edge of the LAP, the lack of a conspicuous outer surface ornament, the widened dorsal tip of the ridge on the inner side of the LAPs, and the very small, well-defined, semi-circular tentacle notch. The shape of the spine articulations in these fossil LAPs, however, differs in displaying an irregularly corrugated proximal edge of the volute. In addition, the dorsal lobe of the spine articulations in the fossil LAPs is dorsally elongate and much larger than the ventral one. On account of these minor, yet significant, differences, the present LAPs are here assigned to a new genus, Reitneracantha gen. nov. However, similarities in LAP morphology are so close that Reitneracantha gen. nov. and Ophiocamax most probably share close phylogenetic ties. From an LAP morphological perspective, the phylogenetic relationships between Reitneracantha gen. nov. and Ophiocamax are probably even closer than between the latter and its extant sister taxon Ophiomitra. Thus, Reitneracantha gen. nov. and Ophiocamax are here considered to be members of the same lineage., Published as part of Thuy, Ben, 2013, Temporary expansion to shelf depths rather than an onshore-offshore trend: the shallow-water rise and demise of the modern deep-sea brittle star family Ophiacanthidae (Echinodermata: Ophiuroidea), pp. 1-242 in European Journal of Taxonomy 48 on page 203, DOI: 10.5852/ejt.2013.48, http://zenodo.org/record/3822836

Dermocoma subtilirugosa (Kristan-Tollmann & Gramann, 1992) comb. nov. Fig. 25: 4-5 Ophiacantha ? subtilirugosa Kristan-Tollmann & Gramann, 1992: 468, pl. 3 figs 1-6. Diagnosis Species of Dermocoma with moderately large LAPs displaying a very fine vertical striation on almost entire outer surface; two very poorly defined spurs on the outer proximal and inner distal edges; up to four small spine articulations in tight notches of non-elevated distal edge. Material examined GZG.INV.78671, GZG.INV.78672 and GZG.INV.78673 (3 dissociated LAPs) from the Rhaetian of Fischerwiese, Austria.. Description Moderately large LAPs; rounded, crescentic (proximal LAPs) to rectangular (distal LAPs) outline; slightly higher than wide (proximal LAPs) to more than twice wider than high (distalmost LAPs); dorsal edge straight to slightly convex, distal edge gently convex; ventral quarter to fifth large and protruding ventro-proximalwards in proximal to median LAPs; proximal edge evenly concave, with up to two small, very poorly defined, weakly prominent and not protruding, almost indiscernible spurs; outer surface almost entirely covered by very fine vertical striation, composed of thin lamellae, distalwards slightly overlapping, proximalwards decreasing in size and fading into finely meshed stereom close to proximal edge of LAP; striation mostly regularly vertical, with occasional irregularities (slightly oblique and/or branching lamellae) in ventral half of outer surface. Three (distal LAPs) to four (proximal LAPs) small, ear-shaped, nearly equal-sized spine articulations in tight notches of distal edge, interrupting vertical striation; gaps separating spine articulations increasing in size dorsalwards; dorsal and ventral lobes of spine articulations forming continuous volute; very narrow gap between spine articulations and distal edge of LAP. Ventral edge of proximal LAPs with large but weakly concave tentacle notch; tentacle perforation ventro-distally bordering ventralmost spine articulation in distal LAPs. Inner side of proximal and median LAPs with narrow, well-defined, prominent ridge separated by rounded kink into dorsal and ventral portions; dorsal portion oblique, bent dorso-proximalwards, with widened slightly less prominent and less well-defined dorsal tip; ventral portion much shorter than dorsal one, pointing ventro-proximalwards, sharply separated from thickened ventral edge of LAP; ridge in distal LAPs short, oblique, well-defined, prominent, without kink, bone-shaped to triangular. Very faint vertical row of small, irregular perforations close to distal edge of LAPs, separating inner side into coarsely meshed main portion, and narrow, finely meshed distal portion. Tentacle notch in proximal and median LAPs large, distally bordered by narrow, oblique ridge. Remarks LAPs similar to the ones described here were first recorded from the Rhaetian of rocks dredged from the northern Exmouth Plateau and described as Ophiacantha ? subtilirugosa by Kristan-Tollmann & Gramann (1992). The new material from the Rhaetian of Austria now enables a reassessment of this species in accordance with the most recently set standards in ophiuroid micropalaeontology (Thuy & Stöhr 2011). The shape, size and position of the spine articulations, the outer surface ornament and the shape of the ridge on the inner side strongly suggest assignment to Dermocoma. Among the LAP types assigned to this genus, the present one differs in combining small spine articulations with a fine vertical striation which covers almost the entire outer surface and two almost indiscernible spurs on the outer proximal and inner edges. Occurrence Rhaetian of Austria and the Wombat Plateau off northern Australia., Published as part of Thuy, Ben, 2013, Temporary expansion to shelf depths rather than an onshore-offshore trend: the shallow-water rise and demise of the modern deep-sea brittle star family Ophiacanthidae (Echinodermata: Ophiuroidea), pp. 1-242 in European Journal of Taxonomy 48 on pages 138-139, DOI: 10.5852/ejt.2013.48, http://zenodo.org/record/3822836, {"references":["Kristan-Tollmann E. & Gramann F. 1992. Paleontological evidence for the Triassic age of rocks dredged from the northern Exmouth Plateau (Tethyan foraminifers, echinoderms and ostracodes). In: Rad U. von, Haq B. U. et al. (eds) Proceedings of the Ocean Drilling Program, Scientific Results 122: 463 - 474. College Station, Texas. http: // dx. doi. org / 10.2973 / odp. proc. sr. 122.186.1992","Thuy B. & Stohr S. 2011. Lateral arm plate morphology in brittle stars (Echinodermata: Ophiuroidea): new perspectives for ophiuroid micropalaeontology and classification. Zootaxa 3013: 1 - 47."]}

Ophiotoma vadosa sp. nov. urn:lsid:zoobank.org:act: 698A06E5-BC2D-4729-8C41-15F2EBBFEB3E Fig. 12: 5-7 Diagnosis Species of Ophiotoma with relatively large LAPs displaying large, conspicuous, tongue-shaped and strongly protruding ventro-distal tip; two small, but comparatively well-developed spurs on the outer proximal and inner distal edges; up to six spine articulations displaying strong dorsalward increase in size and in the size of the gaps separating them; dorsal tip of the ridge on the inner side of the proximal LAPs only slightly enlarged. Etymology From vadosus, Latin for “shallow”, in reference to the relatively shallow (mid-shelf) water depth assumed for the palaeohabitat of the species. Type material Holotype GZG.INV.78541. Paratypes GZG.INV.78542 and GZG.INV.78543. Type locality and horizon Blockley, near Cheltenham, Great Britain; shell lenses in clayey matrix, Davoei Zone, early Pliensbachian, Early Jurassic. Additional material GZG.INV.78544 (20 dissociated LAPs) from Blockley, Great Britain; 175 dissociated LAPs from the late Pliensbachian of Seewen, Switzerland, the original material of Hess (1962). Description Holotype GZG.INV.78541 is a dissociated, large, proximal LAP; dorsal and distal edges slightly convex; proximal edge undulose, with small, well-defined, oval, prominent spur positioned in the centre of protruding part of proximal LAP edge; second slightly larger but much less well-defined spur in the middle of the ventral half of the proximal edge; ventral third to quarter of LAP strongly protruding ventro-proximalwards; ventro-distal tip of LAP large, strongly protruding, tongue shaped; distal portion of LAP neither bulging nor elevated; outer surface with well-developed, regular vertical striation composed of thin, distalwards slightly overlapping lamellae, replaced by finely meshed stereom on ventral portion of LAP and near proximal edge. Six ear-shaped spine articulations in notches of distal edge; strong dorsalward increase in size of spine articulations and of gaps separating them; no connecting ridge with striation of outer surface; dorsal and ventral lobes of spine articulations separated by very small incision proximally; large and ventrally strongly increasing gap between spine articulations and distal edge. Ventral edge with very large, deeply concave, conspicuous tentacle notch, exacerbated by strongly protruding ventro-distal tip of LAP. Inner side of LAP with large, sharply defined, prominent, bent ridge; dorsal tip of ridge only very slightly widened, pointing dorsalwards; ventral tip of ridge merged with ventral portion of LAP; inner side of distal edge of LAP with two spurs, dorsal one of which small, round, poorly defined, very slightly prominent but not protruding; ventral spur much larger, better defined, prominent, lenticular; inner side of tentacle notch slightly wider than one-third of the total ventral LAP edge width. Irregular vertical row of perforations, ventralmost of which dorsally bordering tentacle notch, moderately large; remaining perforations minute; row of perforations distally bordered by poorly defined, slightly prominent ridge. Paratype supplements and variation GZG.INV.78542 is a dissociated median LAP, nearly as high as wide; of rectangular to trapezoid outline; dorsal and distal edges oblique, straight; proximal edge slightly undulose, with two small, poorly defined, slightly prominent and very slightly protruding spurs; ventral fifth of LAP protruding; outer surface with vertical striation becoming slightly irregular in ventral half of LAP; striation replaced by finely meshed stereom close to proximal edge of LAP. Four spine articulations in moderately deep notches of distal edge; very weak dorsalward increase in size of spine articulations and of gaps separating them; narrow but ventrally increasing gap between spine articulations and distal edge of LAP. Ventral edge of LAP convex with moderately large, weakly concave tentacle notch. Inner side with large, sharply defined ridge; dorsal tip of ridge slightly widened, ventral tip separated from ventral portion of LAP; inner side of distal edge of LAP with two small, moderately well-defined, slightly prominent spurs; inner side of tentacle notch slightly smaller than one-quarter of the total ventral edge of the LAP. Poorly defined, irregular perforation halfway between ridge and distal edge of LAP. GZG.INV.78543 is a dissociated distal LAP, approximately 1.5 times wider than high, of rectangular outline; well in agreement with other paratype; ventral portion of LAP hardly protruding. Inner side of LAP with sharply defined, prominent, bone-shaped ridge; dorsal and ventral tips of ridge strongly widened. Remarks These LAPs show a certain resemblance with LAPs assigned to Dermocoma (see below), in particular on account of the relatively deep notches holding the spine articulations and the spurs on the outer proximal and inner distal edges. These similarities, however, are superficial at most. In fact, the very large tentacle notches clearly preclude assignment to Dermocoma. Among the large-pored ophiacanthid lineages, greatest similarities are shared with the LAPs of extant Ophiotoma and the fossil LAP types assigned to that genus. Thus, in spite of the rather atypically well-developed spurs on the outer proximal and inner distal edges, the above-described LAPs are assigned to Ophiotoma. Within this genus, the LAPs in question are highly distinctive on account of the spurs and their very large, conspicuous, tongue-shaped ventro-distal tip, which is why they are described as a new species. Occurrence Early Pliensbachian of Great Britain and Late Pliensbachian of Switzerland., Published as part of Thuy, Ben, 2013, Temporary expansion to shelf depths rather than an onshore-offshore trend: the shallow-water rise and demise of the modern deep-sea brittle star family Ophiacanthidae (Echinodermata: Ophiuroidea), pp. 1-242 in European Journal of Taxonomy 48 on pages 59-60, DOI: 10.5852/ejt.2013.48, http://zenodo.org/record/3822836, {"references":["Hess H. 1962. Mikropalaontologische Untersuchungen an Ophiuren II: Die Ophiuren aus dem Lias (Pliensbachien-Toarcien) von Seewen (Kt. Solothurn). Eclogae geologicae Helvetiae 55: 609 - 656."]}

Ophiacanthidae gen. et sp. nov. innom. Fig. 37: 8-9 Material examined GZG.INV.78802, GZG.INV.78803 and GZG.INV.78804 (dissociated LAPs) from the Bimammatum Zone, late Oxfordian, Late Jurassic of the Plettenberg, Germany. Description GZG.INV.78802 is a dissociated, tiny, proximal LAP; very fragile, dorso- and ventro-proximal tips missing; originally at least twice higher than wide; distal edge convex; outer surface with finely and moderately densely meshed stereom. At least six very large, densely spaced spine articulations freestanding on elevated distal portion of LAP; shape of spine articulations very unusual, complex; dorsal lobe very large, distally encompassing several openings of variable size; sigmoidal fold well developed but very short, proximally bordering very small nerve opening; ventral lobe very slender, proximally merged with dorsal lobe; spine articulations slightly oval, horizontally elongate; middle spine articulations largest, with dorsalward and ventralward decrease in size; spine articulations proximally sharply bordered by straight, well-defined but weakly prominent edge of elevated distal portion of LAP; gap between spine articulations and distal edge of LAP generally narrow, widest near middle spine articulations. No tentacle notch discernible in external view. Inner side of LAP with very slender, moderately well-defined, weakly prominent, oblique and nearstraight ridge with widened, vertically elongate dorsal tip composed of more finely meshed stereom; ventral tip of ridge indiscernible or poorly preserved; single, well-defined, prominent, oval spur composed of densely meshed stereom in ventral half of inner side of distal LAP edge; inner side of tentacle notch not preserved or indiscernible. No perforations or furrow discernible. GZG.INV.78803 is a dissociated median or distal LAP, strongly broken; outer surface with very densely meshed stereom. At least four very closely spaced spine articulations similar to those observed on the proximal specimen described above, displaying dorsalward increase in size; row of spine articulations ventrally bordered by very large, oblique, lenticular, round, strongly prominent ridge-like structure composed of dense stereom. Inner side of LAP with very slender, moderately well-defined, prominent ridge similar to the main part of the ridge observed on the previous specimen; ventral tip of ridge merged with large, well-defined, strongly prominent, oblique, elongate knob composed of densely meshed stereom; spur on inner side of distal edge of LAP much larger than in previous specimen; very large, round, lenticular, strongly prominent structure ventrally bordering row of spine articulations almost completely exposed in internal view. Remarks These specimens probably are among the most unusual ophiuroid LAPs ever recorded. The very weird, complex spine articulations display a sigmoidal fold, which suggests that the LAPs in question are assignable to the Ophiacanthidae. Affinities within this family, however, are purely speculative. These LAPs appear so highly derived that it is difficult, if not impossible, to deduce any phylogenetic relationships with other ophiacanthids on the basis of LAP morphology. It is even unfeasible to determine with certainty if this LAP type belongs to a large-pored or a small-pored ophiacanthid. To make matters worse, the material available is very limited and fragmentary, which hampers a proper systematic assessment of this highly intriguing LAP type. Striking similarities in the structure of the spine articulations are shared with the LAPs of the ophiocomid Ophiopteris papillosa Lyman, 1875. It cannot be ruled out that these similarities reflect close phylogenetic ties, which would place the present LAP type in the Ophiocomidae Ljungman, 1867. However, most of the other characters, in particular the size and fragility of the LAPs, the shape of the ridge on the inner side, the enigmatic structure ventrally bordering the row of spine articulations and the absence of perforations on the inner side, differ fundamentally. It thus seems more probable that the similarly shaped spine articulations were acquired independently. In the absence of more material, this LAP type cannot be formally described. It is clear, however, that it represents a new genus and species most probably assignable to the Ophiacanthidae. It is hoped that more material of this intriguing LAP type will be discovered in order to investigate its phylogenetic position and speculate on the function of the unusual spine articulation morphology and the enigmatic structure ventrally bordering the row of spine articulations.

Ophiojagtus argoviensis (Hess, 1966) comb. nov. Fig. 37: 10-11 Hemieuryale ? argoviensis Hess, 1966: 1040, 1052, figs 24-25, 67-69. Diagnosis Species of Ophiojagtus gen. nov. with relatively small LAPs displaying a broad and short ventral portion accounting for approximately one-quarter of the total LAP height; proximal edge occasionally with very weak, rounded protrusion; five to six spine articulations with weak dorsalward increase in size and slightly stronger dorsalward increase in the size of the gaps separating them; ridge on the inner side relatively slender, evenly bent, with slightly widened dorsal tip and with ventral half extending well onto the ventral portion of the LAP. Material examined NHMB M1124, NHMB M11225 and 3 dissociated LAPs from the late Oxfordian of Savigna, France, the type material of Hess (1966); GZG.INV.78805 (1 dissociated LAP) from sample S1 of Gale (2011), GZG.INV.78806 (2 dissociated LAPs) from sample S2a of Gale (2011) and GZG.INV.78807 (4 dissociated LAPs) from sample S2b of Gale (2011), all from the Bifurcatus Zone, late Oxfordian of Savigna, France; 2 dissociated LAPs from the Bifurcatus Zone of Guldental, Switzerland, the original material of Hess (1966). Description Relatively small dissociated LAPs; of thick, massive, strongly curved general aspect; more than twice higher than wide (proximal LAPs) to approximately 1.5 times higher than wide (median to distal LAPs); dorsal edge rounded; distal edge convex; proximal edge concave, generally with very weak, rounded protrusion; no spurs; ventral portion of the LAPs broad, weakly widened ventrally, relatively short, accounting for one-quarter of the total LAP height; outer surface with finely meshed stereom, devoid of conspicuous ornament elements. Five to six large, ear-shaped spine articulations freestanding on bulging distal portion of LAP and composed of a thick, continuous volute; spine articulations not sharply bordered proximally; weak dorsalward increase in size of spine articulations and slightly larger dorsalward increase in size of gaps separating them; gap between spine articulations and distal edge of LAP narrow. Inner side of LAPs with well-defined, prominent, relatively slender, gently bent ridge; dorsal half of ridge pointing dorso-proximalwards, with slightly widened dorsal tip; ventral half of ridge extending onto most of the ventral portion of the LAP but not merged with the latter; no spurs on inner side of the distal edge of LAP; inner side of the tentacle notch moderately large, poorly defined, very shallow. Few, small, scattered perforations in shallow, moderately well-defined vertical furrow dorsally bordering tentacle notch. Remarks This type of LAP was originally described by Hess (1966) as Hemieuryale ? lunaris on the basis of dissociated LAPs and vertebrae from the Oxfordian of Switzerland and France. A re-examination of the type material, in addition to new finds of dissociated LAPs from the Oxfordian of France, has now revealed that this LAP type displays the distinctive combination of characters unambiguously warranting assignment to Ophiojagtus gen. nov. Occurrence Late Oxfordian of France and Switzerland., Published as part of Thuy, Ben, 2013, Temporary expansion to shelf depths rather than an onshore-offshore trend: the shallow-water rise and demise of the modern deep-sea brittle star family Ophiacanthidae (Echinodermata: Ophiuroidea), pp. 1-242 in European Journal of Taxonomy 48 on pages 215-216, DOI: 10.5852/ejt.2013.48, http://zenodo.org/record/3822836, {"references":["Hess H. 1966. Mikropalaontologische Untersuchungen an Ophiuren V: Die Ophiuren aus dem Argovien (unteres Ober-Oxford) vom Guldental (Kt. Solothurn) und von Savigna (Dept. Jura). Eclogae geologicae Helvetiae 59: 1025 - 1063.","Gale A. S. 2011. Asteroidea (Echinodermata) from the Oxfordian (Late Jurassic) of Savigna, Departement du Jura, France. Swiss Journal of Palaeontology 130 (1): 69 - 89. http: // dx. doi. org / 10.1007 / s 13358 - 010 - 0008 - x"]}

Lapidaster lukenederi sp. nov. urn:lsid:zoobank.org:act: 7E64C5B3-CAFF-4342-AD67-DDB05F3050EB Fig. 10: 1-3 Diagnosis Species of Lapidaster gen. nov. with small LAPs displaying a low height/width ratio and a welldeveloped constriction; ventral portion of LAP not thickened; spur on the outer proximal and inner distal edges very poorly defined; dorsal part of ridge on inner side not widened. Etymology Named in honour of Alexander Lukeneder (Naturhistorisches Museum Wien, Vienna), who collected and generously provided the residues yielding the type material of the new species. Type material Holotype NHMW 2012/0138/0001. Paratypes NHMW 2012/0138/0002 and NHMW 2012/0138/0003. Type locality and horizon KB1-A section of Lukeneder (2004) in the Ternberg Nappe, Austria; Verrucosum Zone, late Valanginian, Early Cretaceous. Additional material NHMW 2012/0138/0004 (88 dissociated LAPs). Description Holotype NHMW 2012/0138/0001 is a dissociated, small, proximal to median LAP, approximately 1.5 times wider than high, with gently convex distal edge; dorsal edge clearly concave, indicating a slight constriction of the outer surface; ventral fifth of LAP protruding ventro-proximalwards; ventro-distal tip of LAP not conspicuously large, slightly protruding ventro-distalwards; proximal edge of LAP angular, with small very faint, hardly discernible, spur-like structure near ventro-proximal tip of LAP; outer surface with coarsely meshed stereom; trabeculae of outer surface stereom showing no tendency to merge into vertical striation. Four relatively small spine articulations, ventralmost slightly smaller than remaining three; very small dorsalward increase in size of gaps separating spine articulations; dorsal and ventral lobes composing volute connected by very short, markedly narrow ridge proximally; dorsalmost spine articulation pointing dorsalwards; all spine articulations embedded in outer surface stereom. Ventral edge of LAP with moderately large, gently concave tentacle notch. Inner side of LAP with relatively narrow, well-defined ridge, dorsal portion of which nearly straight, widest in middle part, with narrow tip not reaching dorsal and distal edges of LAP; ventral portion of ridge separated from dorsal one by kink, shorter, wider, less well defined but not confluent with ventral part of LAP; ventral part of LAP not thickened; ventro-distal tip of LAP with barely discernible spur composed of slightly denser stereom; inner side of tentacle notch with coarsely meshed stereom, hardly stretched horizontally. No perforations visible on inner side. Paratype supplements and variation NHMW 2012/0138/0002 is a dissociated median LAP, approximately twice wider than high; ventrodistal tip of LAP slightly larger than in holotype; dorsal edge strongly concave, indicating well-developed constriction; proximal edge gently concave with small, very poorly defined, barely visible spur close to ventro-proximal tip of LAP; outer surface with coarsely meshed stereom with very weak tendency of trabeculae to merge into irregular vertical striation. Three equal-sized spine articulations, separated by equal-sized gaps. Inner side of LAP generally well in agreement with that of holotype; dorsal portion of ridge straight, slightly widened dorsally; ventral portion of ridge wider, very short, poorly defined but not confluent with ventral part of LAP; no spur discernible on inner side of ventro-distal tip of LAP. NHMW 2012/0138/0003 is a dissociated distal plate, more than twice wider than high; both dorsal and ventral edges concave as a result of the constriction; no spur discernible on proximal edge of LAP. Three equal-sized spine articulations near distal edge of LAP, separated by equal-sized gaps. Ventral edge of LAP with large, gently concave tentacle notch. Inner side with moderately well-defined ridge, oblique and slightly bent, relatively wide, short; no kink separating ridge into dorsal and ventral portions; ventral tip of ridge widest, best defined; no spur discernible on inner side of ventro-distal tip of LAP. Remarks These LAPs share greatest similarities with those of Lapidaster etteri sp. nov., especially with regard to the constriction and the height/width ratio of the proximal LAPs. In the latter, however, the the ventral part is more strongly thickened, the dorsal tip of the ridge on the inner side is widened, and the spur on the outer proximal and inner distal edges is slightly better defined. Occurrence Late Valanginian of Austria., Published as part of Thuy, Ben, 2013, Temporary expansion to shelf depths rather than an onshore-offshore trend: the shallow-water rise and demise of the modern deep-sea brittle star family Ophiacanthidae (Echinodermata: Ophiuroidea), pp. 1-242 in European Journal of Taxonomy 48 on pages 46-47, DOI: 10.5852/ejt.2013.48, http://zenodo.org/record/3822836, {"references":["Lukeneder A. 2004. The Olcostephanus Level: an Upper Valanginian ammonoid mass-occurrence (Lower Cretaceous, Northern Calcareous Alps, Austria). Acta Geologica Polonica 54 (1): 23 - 33."]}

Genus Alternacantha Thuy & Meyer, 2013 Type species Alternacantha occulta Thuy & Meyer, 2013, by original designation. Diagnosis Ophiacanthid with large LAPs displaying a relatively large, ventro-proximalwards protruding ventral portion; small tentacle notch; large, ear-shaped spine articulations with the position of the dorsalmost spine articulation alternating between close to the remaining ones and widely separated from the latter. Remarks In terms of LAP morphology, Alternacantha is probably among the most distinctive and unambiguously identifiable ophiacanthids. In fact, the alternating position of the dorsalmost spine articulation, varying from close to the remaining spine articulations to widely separated from the latter, is a feature not found in any other LAP type. Since Alternacantha is known from well-preserved, articulated specimens (Thuy & Meyer 2013), its phylogenetic position is well understood. Together with its extinct sister taxon Dermocoma, it holds a basal position within the large-pored ophiacanthids displaying well-developed disc plates rather than translucent scales obscured by skin. Indeed, the close phylogenetic relationship with Dermocoma is reflected by LAP morphology. Both genera share ear-shaped spine articulations sunken in shallow notches of the gently elevated distal edge, a strongly ventro-proximally protruding ventral portion of the LAPs, strongly protruding spurs on the outer proximal edge, and a relatively simple ridge on the inner side devoid of sharp kinks or an exceedingly widened dorsal part. While proximal LAPs of the two genera can be readily differentiated, median and, in particular, distal LAPs can be so closely similar that distinction is very difficult, if possible at all. Thus, it is crucial for records based exclusively on dissociated LAPs to focus on well-preserved proximal LAPs in these genera. It should be stressed that it is strongly advisable in general to choose adult proximal LAPs as holotypes of new ophiuroid species known solely from dissociated LAPs, as clearly stressed by Thuy & Stöhr (2011). Unfortunately, the holotype of Ophiacantha ? suprajurassica Hess, 1965 is a median LAP from strata which have yielded both Dermocoma and Alternacantha. In view of the near-identical morphologies of median and distal LAPs in these two genera, the holotype in question cannot be unambiguously assigned. Ophiacantha ? suprajurassica should therefore be considered as a nomen dubium, even though non-type specimens assigned to Ophiacantha ? suprajurassica by Hess (1965a, 1966) can be assigned beyond doubt. The closest extant relative of Alternacantha is Ophiocopa Lyman, 1883, which is sister to the clade formed by Alternacantha and Dermocoma. Again, the close phylogenetic ties are reflected by LAP morphology. In fact, the LAPs of extant Ophiocopa spatula Lyman, 1883 (Fig. 22: 3-4) closely resemble those of the two fossil genera, in particular on account of the ventro-proximalwards protruding ventral portion of the LAP, the shape, number and position of the spine articulations, the outer surface ornament and the conspicuous, strongly protruding spur on the outer proximal edge. Differences pertain mainly to the shape of the ridge on the inner side of the LAPs, which in Ophiocopa is composed of a slightly bent, oblique dorsal part with a triangular tip, widely separated from a short knob-like part on the ventral portion of the inner side. All currently known species of Alternacantha share strongly similar, near-identical LAP morphologies, making a distinction on the basis of dissociated LAPs a major challenge. Similarly indistinguishable LAP morphologies have been reported from closely related extant taxa (Thuy & Stöhr 2011). Fortunately, most species of Alternacantha are known from articulated arm fragments, in addition to the dissociated LAPs, providing additional features for species-level distinction., Published as part of Thuy, Ben, 2013, Temporary expansion to shelf depths rather than an onshore-offshore trend: the shallow-water rise and demise of the modern deep-sea brittle star family Ophiacanthidae (Echinodermata: Ophiuroidea), pp. 1-242 in European Journal of Taxonomy 48 on pages 123-125, DOI: 10.5852/ejt.2013.48, http://zenodo.org/record/3822836, {"references":["Thuy B. & Meyer C. A. 2013. The pitfalls of extrapolating present-day depth ranges to fossil communities: new insights from brittle stars (Echinodermata: Ophiuroidea) from the Middle Jurassic of Switzerland. Swiss Journal of Palaeontology 132 (1): 5 - 21. http: // dx. doi. org / 10.1007 / s 13358 - 012 - 0048 - 5","Thuy B. & Stohr S. 2011. Lateral arm plate morphology in brittle stars (Echinodermata: Ophiuroidea): new perspectives for ophiuroid micropalaeontology and classification. Zootaxa 3013: 1 - 47.","Hess H. 1965 a. Mikropalaontologische Untersuchungen an Ophiuren IV: Die Ophiuren aus dem Renggeri-Ton (Unter-Oxford) von Chapois (Jura) und Longecombe (Ain). Eclogae geologicae Helvetiae 58: 1059 - 1082.","Hess H. 1966. Mikropalaontologische Untersuchungen an Ophiuren V: Die Ophiuren aus dem Argovien (unteres Ober-Oxford) vom Guldental (Kt. Solothurn) und von Savigna (Dept. Jura). Eclogae geologicae Helvetiae 59: 1025 - 1063."]}

Krohcoma mira sp. nov. urn:lsid:zoobank.org:act: 79C26A85-E693-4AF7-8A41-36FB956BE7ED Fig. 15: 4-6 Diagnosis Species of Krohcoma gen. nov. with relatively small LAPs, displaying very poorly defined, large spur in the middle of the proximal edge; up to five very large, equal-sized spine articulations; row of spine articulations protruding ventrally; tentacle notch very large, equalling half of the total ventral LAP edge width; ridge on inner side of LAPs merged with ventral LAP edge. Etymology Name derived from mirus, Latin for “astonishing”, in reference to the palaeohabitat of the species suggesting a deep-water origin of the genus and thus challenging widely accepted concepts on the role of the deep sea in macroevolutionary patterns. Type material Holotype NHMW 2012/0137/0013. Paratypes NHMW 2012/0137/0014 and NHMW 2012/0137/0015. Type locality and horizon Glasenbach Gorge, Austria; Hauptknollenbrekzie, late Sinemurian to early Pliensbachian, Early Jurassic. Additional material NHMW 2012/0137/0015 (10 dissociated LAPs). Description Holotype NHMW 2012/0137/0013 is a dissociated, small, proximal LAP; nearly as high as wide; dorsal edge slightly convex; distal edge oblique, convex; proximal edge irregularly undulose, with very poorly defined, prominent and slightly protruding central spur composed of slightly more densely meshed stereom; ventro-proximal tip of LAP thickened into very poorly defined, prominent spur composed of slightly more densely meshed stereom; outer surface with moderately finely meshed stereom, devoid of conspicuous ornament elements. Five very large, ear- to horseshoe-shaped spine articulations, freestanding in dorso-proximally receding row on strongly bulging distal portion of LAP; dorsal and ventral lobes of spine articulations very thick, proximally merged by relatively thin connection into continuous lobe encompassing conspicuously large muscle opening; spine articulations nearly equal sized and equi-distant; row of spine articulations protruding ventrally. Ventral edge of LAP straight except for protruding ventral tip of spine articulation row; tentacle notch not visible in external view. Inner side of LAP with relatively small, narrow, sharply defined, prominent and slightly bent ridge; dorsal tip of ridge pointing dorso-proximalwards, not widened; ventral portion of ridge merged with thickened ventral edge of LAP; inner side of distal edge of LAP with poorly defined, slightly prominent but not protruding spur composed of slightly more densely meshed stereom; inner side of tentacle notch very large, accounting for approximately half of the total ventral LAP edge width. No perforations discernible. Paratype supplements and variation NHMW 2012/0137/0014 is a dissociated median LAP; slightly wider than high; dorsal edge straight to slightly concave. Four very large, nearly equal-sized spine articulations similar to those observed on holotype; very weak dorsalward increase in size of gaps separating spine articulations; row of spine articulations only slightly protruding ventrally. Ventral edge of LAP nearly straight. Inner side of LAP well in agreement with that of holotype; no spur discernible on inner side of distal edge of LAP. NHMW 2012/0137/0015 is a dissociated distal LAP; almost twice wider than high; dorsal edge clearly concave as a result of a well-developed constriction; proximal edge with rather poorly defined, prominent and very slightly protruding central spur composed of slightly more densely meshed stereom; ventral sixth of LAP slightly protruding ventro-proximalwards. Four very large, equal-sized, ear- to horseshoeshaped spine articulations on elevated distal portion of LAP, arranged in dorso-proximally receding row; very slight dorsalward increase in size of gaps separating spine articulations. Ventral edge with very large, weakly concave tentacle notch. Inner side of LAP obscured by sediment. Remarks These LAPs can be easily differentiated from almost every other type of LAPs on account of the distinctive dorso-proximally receding row of very large spine articulations. Within the group of LAPs that display the latter character, here assigned to Krohcoma gen. nov., the above-described ones are unique in having equal-sized spine articulations and very large tentacle notches accounting for nearly half of the total ventral LAP edge width. Occurrence Late Sinemurian to early Pliensbachian of Austria., Published as part of Thuy, Ben, 2013, Temporary expansion to shelf depths rather than an onshore-offshore trend: the shallow-water rise and demise of the modern deep-sea brittle star family Ophiacanthidae (Echinodermata: Ophiuroidea), pp. 1-242 in European Journal of Taxonomy 48 on pages 79-80, DOI: 10.5852/ejt.2013.48, http://zenodo.org/record/3822836

Ophiogaleus sp. nov. innom. 1 Fig. 19: 10-12 Material examined NHMW 2012/0137/0017, NHMW 2012/0137/0018, NHMW 2012/0137/0019 and NHMW 2012/0137/0020 (12 dissociated LAPs) from the late Sinemurian to early Pliensbachian of the Glasenbach Gorge, Austria. Description Relatively large, dissociated proximal to median, fragmentary LAPs; originally much higher than wide; dorsal edge not preserved; well-developed constriction; distal edge convex; proximal edge irregularly undulose; at least one large, moderately well-defined, prominent and slightly protruding, oval spur in the ventral half of the proximal edge, composed of more densely meshed stereom; outer surface with moderately finely meshed stereom, replaced by more finely meshed stereom in a relatively broad band paralleling proximal edge of LAP; trabecular intersections of outer surface stereom not thickened or developed into granules. At least six large, ear-shaped spine articulations freestanding on strongly elevated distal portion of LAP; dorsal and ventral lobes of spine articulations merged into continuous, conspicuously oblique volute; spine articulations proximally sharply bordered by well-defined but weakly prominent, near-straight ridge; very weak dorsalward increase in size of spine articulations and of gaps separating them; relatively narrow gap between spine articulations and distal edge of LAP; row of spine articulations originally most probably slightly protruding ventralwards. Inner side of LAPs with large, sharply defined and prominent ridge; ventral part long, relatively narrow, strongly bent, ventral tip slightly pointed, sharply separated from ventral portion of LAP; dorsal part of ridge fragmentary in all available LAPs, slightly widened, small, vertically elongate, exact outline not unambiguously determinable; inner side of distal edge of LAP with one to two small, moderately well to poorly defined, horizontally elongate and slightly prominent spurs; inner side of tentacle notch relatively large, well defined laterally. No perforations or furrow discernible. Remarks The limited amount of material available and its fragmentary condition make a sound systematic assessment difficult. While assignment to the Ophiacanthidae is unquestionable on account of the spine articulation structure and the morphology of the inner side, affinities within this family are more problematic. Greatest similarities are shared with the LAPs of Ophiogaleus gen. nov. on account of the number, position and shape of the spine articulations and the number and position of spurs on the outer proximal and inner distal edges. The shape of the ridge on the inner side, however, is rather atypical for Ophiogaleus gen. nov. with respect to the narrow dorsal part of the ridge. In the light of the similarly atypical ridge in Ophiogaleus dorecki (Hess, 1962) comb. nov. (see below), known from more complete material, assignment to Ophiogaleus gen. nov. seems justified after all, especially considering the possibility that the above-described specimens and the slightly younger O. dorecki are two stratigraphically closely spaced representatives of the same lineage. Within Ophiogaleus gen. nov., the LAPs described above are unique in displaying oblique spine articulations. The fragmentary nature of the record, however, precludes a formal description of this species in the present study., Published as part of Thuy, Ben, 2013, Temporary expansion to shelf depths rather than an onshore-offshore trend: the shallow-water rise and demise of the modern deep-sea brittle star family Ophiacanthidae (Echinodermata: Ophiuroidea), pp. 1-242 in European Journal of Taxonomy 48 on pages 109-110, DOI: 10.5852/ejt.2013.48, http://zenodo.org/record/3822836, {"references":["Hess H. 1962. Mikropalaontologische Untersuchungen an Ophiuren II: Die Ophiuren aus dem Lias (Pliensbachien-Toarcien) von Seewen (Kt. Solothurn). Eclogae geologicae Helvetiae 55: 609 - 656."]}

Genus Ophiacantha Müller & Troschel, 1842 Type species Ophiacantha spinulosa Müller & Troschel, 1842 [junior synonym of Ophiacantha bidentata (Bruzelius, 1805)], by original designation. Diagnosis LAPs with dorsal and ventral lobes of spine articulations fused into continuous volute; ventral part of LAPs not protruding ventro-proximalwards; generally no more than one spur on the outer proximal and inner distal edges; ridge on inner side composed of long, oblique, straight to slightly bent main part with a pointed dorsal tip and with ventrally pointing, vertical to slightly oblique or bent extension generally at least as long as half of the main part; in many cases, main part and ventrally pointing extension fused into large, irregularly triangular knob; tentacle notch small. Remarks Ophiacantha is one of the most speciose (Stöhr et al. 2012), but also one of the most heterogeneous genera among the extant ophiuroids (O’Hara & Stöhr 2006). This morphological heterogeneity is also reflected in LAP morphology, as already pointed out by Thuy & Stöhr (2011), with some species sharing greater similarities in LAP morphology to species of other ophiacanthid genera than with their congeners. Thus, working out a comprehensive and at the same time meaningful LAP morphological diagnosis of Ophiacantha is a major challenge. To make matters worse, most characters observed in the LAPs of Ophiacantha also occur in other genera. The most stringent approach is to focus on the LAP morphology of the type species, Ophiacantha bidentata, on the basis of which the LAP morphologies of the other species are assessed. The LAPs of O. bidentata were described in detail and illustrated by Thuy & Stöhr (2011). They are characterised by a ridge on their inner side, which consists of a main oblique, straight to slightly proximally bent part with a pointed dorsal tip and fused dorsally to a ventrally pointing, near-vertical to slightly oblique extension close to the proximal edge of the LAP longer than half of the main part of the ridge. In some cases, the main part of the ridge and its ventrally pointing dorsal extension are merged into a single, large, irregularly triangular knob. In combination with the large ear-shaped spine articulations on a strongly elevated distal portion of the LAP, with dorsal and ventral lobes merged into a continuous volute, and proximally sharply bordered by the distalmost lamella of a well-developed vertical striation on part of the outer surface, the shape of this ridge is distinctive. This is important to note since slightly modified versions of ridge shape are also found in other, not necessarily closely related ophiacanthids (e.g. Ophiomitrella Verrill, 1899; Ophioplinthaca Verrill, 1899, “ Ophiophthalmus ” Matsumoto, 1917). Many species of Ophiacantha share the above-mentioned combination of features, which can be thus considered as the Ophiacantha LAP morphology in its proper sense. Whether the species in question also share similar general skeletal morphologies, and thus potentially represent a true clade with the Ophiacanthidae, remains to be investigated. A number of extant species of Ophiacantha conflict with the type species in terms of LAP morphology. Particularly striking is the occurrence in a number of species of Ophiacantha of a ridge shape otherwise exclusively found in Ophiotreta and Ophiopristis. The species in question include Ophiacantha anomala G.O. Sars, 1872, O. rosea Lyman, 1878, O. spectabilis G.O. Sars, 1872 and O. vivipara Ljungman, 1872. Remarkably, these four species are known to have closely similar general skeletal morphologies in common (Paterson 1985; O’Hara & Stöhr 2006), thus most probably form a phylogenetically consistent group. A detailed reassessment of the species in question is likely to result in separation at the generic level, which would gain support from evidence of LAP morphology. Other species currently assigned to Ophiacantha differ from the type species in displaying generally lower LAPs (smaller height/width ratios), proximally separated dorsal and ventral lobes of the spine articulations which thus become slightly horizontally elongate rather than round, a single protruding spur in the middle of the outer proximal and inner distal edges, and a densely meshed or even granulated stereom covering the outer surface rather than a vertical striation. At the same time, they share the highly distinctive shape of the ridge on the inner side with Ophiacantha bidentata. Such taxa include Ophiacantha smitti Ljungman, 1872, O. pentagona Koehler, 1897, O. prionota H.L. Clark, 1911 and O. levispina Lyman, 1878. Whether this grouping is artificial or, indeed, reflects general skeletal morphological similarities is in need of further study. Remarkably, the species in question are closer to species of Ophiolebes Lyman, 1878 in terms of LAP morphology than to their congeners. According to the revised cladistic phylogeny presented here, Ophiacantha is sister taxon to the Ophiolebes - Ophialcaea clade. Unfortunately, LAPs of extant species of Ophialcaea Verrill, 1899 could not be examined using the standards set by Thuy & Stöhr (2011). Ophiolebes, however, is shown here to share largely similar LAP morphologies with Ophiacantha, in particular with the species mentioned above.Similar to those of the latter, the LAPs of Ophiolebes display a ridge that is superficially comparable to the one seen in Ophiacantha bidentata. The main distinction between the LAPs of Ophiolebes and those of O. bidentata and similar congeners are the proximally separated dorsal and ventral lobes of the spine articulations. To conclude, as currently understood, the genus Ophiacantha obviously unites a number of fundamentally different LAP morphologies, some of which definitely reflect differences at the generic level to be worked out in detail by future studies. It is very difficult to characterise the LAP morphology of the genus convincingly, even if restricted to the type species and species with morphologically similar LAPs. The ridge shape described above for Ophiacantha bidentata, along with spine articulations freestanding on the elevated distal edge of the LAP, with dorsal and ventral lobes fused into a continuous volute, and bordered proximally by a not exceedingly thickened distalmost lamella is a combination which probably comes closest to a diagnosis of the LAP morphology of Ophiacantha in its proper sense. For the purpose of the present, only fossil LAPs displaying this combination of characters are assigned to Ophiacantha., Published as part of Thuy, Ben, 2013, Temporary expansion to shelf depths rather than an onshore-offshore trend: the shallow-water rise and demise of the modern deep-sea brittle star family Ophiacanthidae (Echinodermata: Ophiuroidea), pp. 1-242 in European Journal of Taxonomy 48 on pages 98-99, DOI: 10.5852/ejt.2013.48, http://zenodo.org/record/3822836, {"references":["Stohr S., O'Hara T. D. & Thuy B. 2012. Global diversity of brittle stars (Echinodermata: Ophiuroidea). PLoS One 7 (3): e 31940. http: // dx. doi. org / 10.1371 / journal. pone. 0031940","O'Hara T. D. & Stohr S. 2006. Deep water Ophiuroidea (Echinodermata) of New Caledonia: Ophiacanthidae and Hemieuryalidae. In: Richer de Forges B. & Justine J. - L. (eds) Tropical Deep- Sea Benthos 24: 33 - 141. Memoires du Museum national d'Histoire naturelle 193, Museum national d'Histoire naturelle, Paris.","Thuy B. & Stohr S. 2011. Lateral arm plate morphology in brittle stars (Echinodermata: Ophiuroidea): new perspectives for ophiuroid micropalaeontology and classification. Zootaxa 3013: 1 - 47.","Matsumoto H. 1917. A monograph of Japanese Ophiuroidea, arranged according to a new classification. Journal of the College Science, Imperial University Tokyo 38: 1 - 408.","Paterson G. L. J. 1985. The deep-sea Ophiuroidea of the North Atlantic Ocean. Bulletin of the British Museum (Natural History), Zoology Series 49, British Museum, London.","Clark H. L. 1911. North Pacific ophiurans in the collection of the Unites States National Museum. United States National Museum Bulletin 75, Smithsonian Institution, Washington. http: // dx. doi. org / 10.5962 / bhl. title. 1324"]}

Alternacantha occulta Thuy & Meyer, 2013 Fig. 22: 7-8 Synonymy Reference is made to Thuy & Meyer (2013) for a complete synonymy of the species. Diagnosis [complementary to that provided by Thuy & Meyer (2013)] Species of Alternacantha with large LAPs displaying a pointed to tongue-shaped, relatively narrow dorsal edge; outer surface with a well-developed vertical striation; up to four moderately well-developed spurs on the outer proximal and inner distal edges; up to five spine articulations; distal edge of ventral arm plates evenly convex; distal edge of dorsal arm plates parabolic. Material studied GZG.INV.78648, GZG.INV.78649 and GZG.INV.78650 (48 dissociated LAPs) from the early Bajocian of Longwy, France; GZG.INV.78651 (23 dissociated LAPs) from the early Bajocian of Cirey-lès-Nolay, France. Description Large, dissociated LAPs; more than twice wider than high (proximal LAPs) to 1.5 times wider than high (distal LAPs); dorsal edge convex, pointed to round and tongue like in proximal LAPs, concave as a result of a well-developed constriction in median to distal LAPs; distal edge convex; ventral quarter to fifth of LAP strongly protruding ventro-proximalwards; ventro-distal tip of LAP slightly protruding ventralwards, tongue shaped; proximal edge concave with up to four, medium-sized to large, moderately well-developed, prominent, horizontally elongate, pointedly to bluntly protruding spurs of variable position; outer surface with well-developed, fine, regular vertical striation composed of narrow, slightly overlapping lamellae; striation replaced by finely meshed stereom in distal half of outer surface in all LAPs and additionally in dorsal fifth of proximal LAPs. Five (proximal LAPs) to three (distal LAPs) large to very large, ear-shaped spine articulations in moderately shallow notches of elevated distal portion of LAP; dorsal and ventral lobes of spine articulations merged into continuous lobe, with small, very shallow notch at proximal point of contact; spine articulations sharply bordered by edge of notches rather than a well-defined ridge of distalmost lamella; notches deeply incising outer surface striation; strong dorsalward increase in size of spine articulations and of gaps separating them in all LAPs; position of dorsalmost spine articulation varying in position between close to the remaining spine articulations to widely separated from the latter by a gap equalling up to twice the height of the dorsalmost spine articulation in proximal to median LAPs. Ventral edge of LAP with relatively small but deeply incised, concave tentacle notch in all LAPs. Inner side with large, relatively narrow (proximal and median LAPs) to moderately broad (distal LAPs), sharply defined, prominent ridge devoid of kink or thickened part; ventral tip of ridge pointing ventroproximally, not merged with ventral portion of LAP; dorsal half of ridge straight and oblique, not reaching dorsal edge of LAP; inner side of distal edge of LAP with up to four variably well-defined, oval to lenticular, slightly prominent spurs composed of more densely meshed stereom; inner side of tentacle notch relatively small, with coarsely meshed and slightly horizontally stretched stereom. Small, irregular perforations densely grouped in short vertical row dorsally bordering the tentacle notch in proximal to median LAPs; single small perforation dorsally bordering tentacle notch in distal ones. Remark The original description of Alternacantha occulta on the basis of several articulated specimens (Thuy & Meyer 2013) is here complemented by a detailed description of the LAP morphology of the species, including the inner side of the LAPs which is not exposed on the articulated type specimens. As noted above, species of Alternacantha share nearly indistinguishable LAP morphologies, which makes a distinction of A. occulta from species known exclusively from arm fragments and dissociated LAPs a major challenge. In terms of the shape of the ventral and dorsal arm plates, A. occulta is closest to A. dilionessa sp. nov. (see below). In the former, however, the proximal LAPs are smaller, the dorsal edge is pointed to tongue shaped, rather than broad and oblique, and the outer proximal and inner distal edges display up to four, rather than six, spurs. In A. schwermannorum sp. nov., the ventral arm plates have a truncated rather than evenly convex distal edge, and the LAPs are dorsally broad rather than tongue like and display very thin, horizontally elongate rather than oval spurs on the inner distal edge. Alternacantha arges sp. nov. is a much larger species with LAPs devoid of vertical striation, truncated rather than evenly convex distal edges of the ventral plates and distinctively Gauss-curve-shaped rather than parabolic distal edges of the dorsal arm plates., Published as part of Thuy, Ben, 2013, Temporary expansion to shelf depths rather than an onshore-offshore trend: the shallow-water rise and demise of the modern deep-sea brittle star family Ophiacanthidae (Echinodermata: Ophiuroidea), pp. 1-242 in European Journal of Taxonomy 48 on pages 127-128, DOI: 10.5852/ejt.2013.48, http://zenodo.org/record/3822836, {"references":["Thuy B. & Meyer C. A. 2013. The pitfalls of extrapolating present-day depth ranges to fossil communities: new insights from brittle stars (Echinodermata: Ophiuroidea) from the Middle Jurassic of Switzerland. Swiss Journal of Palaeontology 132 (1): 5 - 21. http: // dx. doi. org / 10.1007 / s 13358 - 012 - 0048 - 5"]}

Krohcoma sp. nov. innom. Fig. 15: 7-8 Material examined GZG.INV.78574, GZG.INV.78575 and GZG.INV.78576 (dissociated LAP) from the Patcham Formation, late Bathonian, of Jumara, India. Description of proximal LAP GZG.INV.78574 is a dissociated relatively small, proximal LAP; slightly higher than wide; dorsal edge strongly concave as a result of a well-developed constriction; distal edge obliquely convex; proximal edge irregularly concave, devoid of spurs or thickened parts; outer surface with moderately finely meshed stereom, no conspicuous ornament elements discernible; six very large, ear-shaped to horseshoeshaped spine articulations in continuous, dorso-proximalwards conspicuously receding row on strongly elevated distal portion of LAP; dorsal and ventral lobes of spine articulations thick, proximally merged by relatively thin connection into continuous, horizontally slightly elongate volute; dorsalward increase in size of spine articulations and of gaps separating them; row of spine articulations protruding ventrally. Ventral edge of LAP slightly concave, tentacle notch not visible in external view. Inner side of LAP largely obscured by sediment; ridge not clearly discernible; inner side of distal edge of LAP devoid of spurs; inner side of tentacle notch large, accounting for slightly less than one-third of the total ventral LAP edge width. No perforations dicernible. Description of median to distal LAP GZG.INV.78575 is a dissociated, small, median to distal LAP, with slightly fragmentary dorsoproximal tip; nearly as wide as high; proximal edge devoid of spurs or thickened parts; outer surface with moderately finely meshed stereom. Five very large spine articulations, similar to those observed of holotype but muscle opening not obscured by sediment, very large; spine articulations arranged in dorso-proximally strongly receding row on elevated distal portion of LAP; row of spine articulations very strongly protruding ventrally. Ventral edge of LAP strongly concave as a result of the strongly protruding row of spine articulations. Inner side of LAP with large, moderately well-defined, wide, bent, prominent ridge; dorsal tip of ridge pointing dorso-proximalwards; ventral tip of ridge merged with ventral LAP edge; inner side of distal edge of LAP devoid of spurs; inner side of tentacle notch very large, accounting for at least one-third of the total ventral LAP edge width. No perforations discernible. Remarks These LAPs unquestionably belong to Krohcoma gen. nov. on account of the position and morphology of the spine articulations. The combination of up to six large spine articulations with slight dorsalward increase in size, moderately large tentacle notches, the absence of spurs on the outer proximal and inner distal edges, and the strongly protruding ventral tip of the row of spine articulations distinguishes these two LAPs from the two other species here assigned to Krohcoma gen. nov. These two LAPs clearly represent a new species, the formal description of which, however, requires better-preserved material., Published as part of Thuy, Ben, 2013, Temporary expansion to shelf depths rather than an onshore-offshore trend: the shallow-water rise and demise of the modern deep-sea brittle star family Ophiacanthidae (Echinodermata: Ophiuroidea), pp. 1-242 in European Journal of Taxonomy 48 on pages 80-81, DOI: 10.5852/ejt.2013.48, http://zenodo.org/record/3822836

Eolaxoporus sp. nov. innom. Fig. 6: 5 Material examined GZG.INV.78500 (dissociated LAP) from the Cassian Formation, early Carnian of Milieres, Italy. Description GZG.INV.78500 is a dissociated, small, proximal to median LAP; slightly wider than high; dorsal and distal edges nearly straight; proximal edge gently concave except for very large, conspicuous, strongly protruding, moderately well-defined, prominent and slightly angular spur almost in the middle of the proximal edge and composed of slightly more densely meshed stereom; second much smaller and much less well defined, weakly prominent and non-protruding spur close to ventro-proximal edge of LAP; ventral fifth of LAP strongly protruding ventro-proximalwards; ventro-distal tip of LAP strongly protruding ventralwards, tongue-shaped; outer surface with moderately coarsely meshed stereom. Four moderately large, nearly equal-sized and equidistant spine articulations freestanding on slightly elevated distal portion of LAP; dorsal and ventral lobes of near-equal size, parallel, horizontal, widely separated proximally; gap between spine articulations and distal edge of LAP relatively narrow. Ventral edge of LAP with large, deeply incised, concave tentacle notch. Inner side of LAP with very small, conspicuously slender, sharply defined, prominent, dorsoproximalwards bent ridge; two rather poorly defined, weakly prominent, round spurs on inner side of distal edge of LAP; inner side of tentacle notch very large. No perforations and furrow discernible. Remarks This single LAP displays all diagnostic characters of Eolaxoporus gen. nov. Within this genus, it is unique in having a strongly protruding, slightly angular dorsal spur almost in the centre of the proximal edge, and a very small, slender ridge on the inner side. The LAP in question certainly belongs to a new species which, in the absence of more material, cannot be described formally for now., Published as part of Thuy, Ben, 2013, Temporary expansion to shelf depths rather than an onshore-offshore trend: the shallow-water rise and demise of the modern deep-sea brittle star family Ophiacanthidae (Echinodermata: Ophiuroidea), pp. 1-242 in European Journal of Taxonomy 48 on page 25, DOI: 10.5852/ejt.2013.48, http://zenodo.org/record/3822836

Reitneracantha dissidens sp. nov. urn:lsid:zoobank.org:act: E1A8998E-30EE-4921-B054-371C65DB6C9D Fig. 36: 1-3 Diagnosis As for genus. Etymology From dissidere, Latin for “intractable, dissenting with an established policy”, in reference to the fact that this species challenges established concepts of the role of the deep-sea in macroevolutionary patterns. Type material Holotype NHMW 2012/0137/0029. Paratypes NHMW 2012/0137/0030 and NHMW 2012/0137/0031. Type locality and horizon Glasenbach Gorge, Austria; Hauptknollenbrekzie, late Sinemurian to early Pliensbachian, Early Jurassic. Additional material NHMW 2012/0137/0032 (3 dissociated LAPs). Description Holotype NHMW 2012/0137/0029 is a dissociated, moderately large, proximal LAP; dorsal edge nearly straight, oblique; distal edge convex; proximal edge nearly straight, except for small, very poorly defined, almost indiscernible, weakly prominent and protruding spur; outer surface with finely meshed stereom, devoid of conspicuous ornament. Five large, ear-shaped spine articulations freestanding on strongly elevated distal half of LAP; dorsal edge of spine articulations vertically elongated, with conspicuous central notch, much larger than ventral lobe, merged with the latter into continuous volute; very strong dorsalward increase in size of spine articulations and of gaps separating them; dorsalmost spine articulation largest, well below dorsal edge of LAP, comspicuously dorsalwards pointing; proximal edge of spine articulations irregularly corrugated; spine articulations sharply bordered proximally by edge of elevated portion, except for dorsalmost one; gap between spine articulations and distal edge of LAP as wide as one spine articulation. Ventral edge of LAP nearly straight; tentacle notch invisible in external view. Inner side of LAP with small, sharply defined, prominent, gently bent ridge displaying a ventroproximally bent ventral part not merged with ventral portion of LAP, and a widened, angular dorsal tip; inner side of distal edge of LAP devoid of spurs; inner side of tentacle notch small, well defined laterally, semi circular. No perforations or furrow discernible. Paratype supplements and variation NHMW 2012/0137/0030 is a dissociated median LAP; as high as wide; of rectangular to trapezoid aspect; dorsal edge concave as a result of a constriction; distal edge nearly straight, oblique; proximal edge devoid of spurs. Four spine articulations similar to those observed on holotype; dorsalmost spine articulation much larger than remaining ones and widely separated from the latter, dorsalwards pointing, near dorsal edge of LAP. Ventral edge of LAP straight, no tentacle notch visible. Ridge on inner side of LAP similar to that of holotype but with less strongly widened dorsal tip. NHMW 2012/0137/0031 is a dissociated distal LAP; slightly wider than high; dorsal edge strongly concave as a result of a well-developed constriction; proximal edge gently concave, devoid of spurs. Four spine articulations similar to those of holotype, freestanding on slightly elevated distal third of LAP; dorsalmost spine articulation much larger than remaining ones and widely separated from the latter, pointing dorsalwards, at some distance from the dorsal edge of the LAP. Ventral edge of the LAP concave, no tentacle notch visible in external view. Ridge on inner side of LAP similar to that of holotype but with weakly widened dorsal tip; inner side of distal edge of LAP devoid of spurs; inner side of tentacle notch moderately small, well defined laterally, semi circular. Remarks The taxonomic affinities of these LAPs have been discussed above., Published as part of Thuy, Ben, 2013, Temporary expansion to shelf depths rather than an onshore-offshore trend: the shallow-water rise and demise of the modern deep-sea brittle star family Ophiacanthidae (Echinodermata: Ophiuroidea), pp. 1-242 in European Journal of Taxonomy 48 on pages 204-206, DOI: 10.5852/ejt.2013.48, http://zenodo.org/record/3822836, {"references":["O'Hara T. D. & Stohr S. 2006. Deep water Ophiuroidea (Echinodermata) of New Caledonia: Ophiacanthidae and Hemieuryalidae. In: Richer de Forges B. & Justine J. - L. (eds) Tropical Deep- Sea Benthos 24: 33 - 141. Memoires du Museum national d'Histoire naturelle 193, Museum national d'Histoire naturelle, Paris."]}

Genus Hanshessia Thuy & Meyer, 2013 Type species Hanshessia trochitophila Thuy & Meyer, 2013, by original designation. Diagnosis Ophiacanthid with relatively large LAPs, proximal ones generally at least twice higher than wide; dorsal edge of proximal LAPs round, tongue shaped; ventral part of LAPs protruding ventro-proximalwards; numerous very large, ear-shaped spine articulations on strongly elevated distal portion of LAP; ridge on inner side composed of strongly bent ventral part and straight, near-vertical dorsal part closely paralleling proximal edge of LAP; tip of dorsal ridge part widely separated from dorsal edge of LAP; kink between dorsal and ventral parts of ridge devoid of ventro-proximalwards protruding angle. Remarks Hanshessia is an extinct genus described on the basis of articulated specimens from the Bajocian of Switzerland (Thuy & Meyer 2013) and thus one of the very few fossil ophiacanthid genera for which detailed data on general skeletal morphology are available. The LAPs of the type specimens are well preserved and well known, at least as far as external structures are concerned. The morphology of the inner side, in contrast, could not be directly assessed on the basis of the type specimens. Upon careful re-examination of the latter, however, a few dissociated vertebrae exposing the vertical groove on the lateral side could be observed, allowing for conclusions on the shape of the ridge on the inner side of the LAPs. In fact, the lateral groove on the vertebrae and the ridge on the inner side of the LAPs serve as articulation interface between both skeletal components thus sharing complementary morphologies. Judging from observations on the type specimens, the ridge on the inner side of Hanshessia trochitophila is composed of an oblique, strongly bent ventral part and a slightly longer, straight, near-vertical part sharply interrupted well below the dorsal edge of the LAP and separated from the ventral part by an angular, but not ventro-proximalwards extended, kink. In combination with the numerous, very large spine articulations, the tongue-shaped dorsal edge of the LAPs, and the ventro-proximally protruding ventral portion of the LAPs, the above-described ridge shape is highly distinctive. Closest similarities in LAP morphology are shared with the Ophiotreta - Ophiopristis group. In the latter, however, the ridge on the inner side, although superficially almost identical, generally displays a straight ventral part, a kink with a conspicuous ventro-proximally pointing angle, and a dorsal part which almost reaches the dorsal edge of the LAP. In addition, the LAPs of species of Ophiotreta and Ophiopristis are characterised by a strongly prominent, conspicuous distalmost lamella proximally bordering the spine articulations and commonly displaying a connecting ridge with the ventral lobe of the latter., Published as part of Thuy, Ben, 2013, Temporary expansion to shelf depths rather than an onshore-offshore trend: the shallow-water rise and demise of the modern deep-sea brittle star family Ophiacanthidae (Echinodermata: Ophiuroidea), pp. 1-242 in European Journal of Taxonomy 48 on pages 120-121, DOI: 10.5852/ejt.2013.48, http://zenodo.org/record/3822836, {"references":["Thuy B. & Meyer C. A. 2013. The pitfalls of extrapolating present-day depth ranges to fossil communities: new insights from brittle stars (Echinodermata: Ophiuroidea) from the Middle Jurassic of Switzerland. Swiss Journal of Palaeontology 132 (1): 5 - 21. http: // dx. doi. org / 10.1007 / s 13358 - 012 - 0048 - 5"]}

Ophiomalleus stevenwilsoni sp. nov. urn:lsid:zoobank.org:act: 201BCFBC-5C34-4C2C-827A-30AF0F678279 Fig. 32: 7-9 Diagnosis Species of Ophiomalleus gen. nov. with large LAPs devoid of vertical striation on the outer surface and of spurs on the outer proximal and inner distal edges; up to four large, ear-shaped spine articulations not bordered proximally by a ridge; ridge on inner side of LAP very broad, with widened dorsal tip and shallow, poorly defined furrow in its centre. Etymology Species named in honour of British musician Steven Wilson, one of the contemporaneous masters of originality and creativity, whose music often taught me how to let ideas develop and materialise. Type material Holotype GZG.INV.78748. Paratypes GZG.INV.78749 and GZG.INV.78750. Type locality and horizon Claypit Gott in Sarstedt, Germany; latest Hauterivian, Early Cretaceous. Additional material GZG.INV.78751 (7 dissociated LAPs). Description Holotype GZG.INV.78748 is a dissociated, large, proximal LAP; slightly higher than wide; main portion of LAP nearly rectangular; dorsal and distal edges gently convex; proximal edge gently concave, devoid of spurs; ventral fifth of LAP large, strongly protruding ventro-proximalwards; outer surface with moderately finely meshed stereom, replaced by narrow and slightly sunken band of very finely meshed stereom along proximal edge. Four very large, ear-shaped spine articulations freestanding on elevated distal edge of LAP; spine articulations not bordered proximally by ridge; dorsal and ventral lobes merged into continuous volute; very strong dorsalward increase in size of spine articulations; gap between spine articulations and distal edge of LAP relatively narrow. Ventral edge of LAP with deeply incised but small tentacle notch. Inner side of LAP with large, well-defined, prominent, broad ridge; ventral tip ventro-proximalwards bent, not merged with ventral portion of LAP; dorsal tip widened, round, dorso-proximalwards pointing; shallow, poorly defined furrow in the middle of the ridge, following its course; inner side of distal edge of LAP devoid of spurs; inner side of tentacle notch small, semi circular. Two minute perforations loosely arranged in vertical row dorsally bordering tentacle notch. Paratype supplements and variation GZG.INV.78749 is a dissociated median LAP; slightly wider than high; very well in agreement with holotype; ventral sixth of LAP strongly protruding ventro-proximalwards. Four spine articulations similar to those observed on holotype. Inner side of LAP similar to that of holotype. Shallow, poorly defined, slightly oblique furrow dorsally bordering tentacle notch. GZG.INV.78750 is a dissociated distal LAP; slightly wider than high; dorsal edge concave as a result of a constriction. Three spine articulations similar to those observed on holotype. Tentacle less deeply incised, small. Ridge on inner side of LAP similar to that of holotype, slightly shorter and broader; furrow in the middle of the ridge slightly better defined. No perforations discernible. Remarks These LAPs are unequivocally assignable to Ophiomalleus gen. nov. on account of the massive, nearrectangular aspect of the main portion, the strongly protruding ventral portion, the shape and arrangement of the spine articulations and the shape of the ridge on the inner side. Within this genus, the LAPs described above are unique in entirely lacking vertical striation on the outer surface and spurs on the outer proximal and inner distal edges., Published as part of Thuy, Ben, 2013, Temporary expansion to shelf depths rather than an onshore-offshore trend: the shallow-water rise and demise of the modern deep-sea brittle star family Ophiacanthidae (Echinodermata: Ophiuroidea), pp. 1-242 in European Journal of Taxonomy 48 on pages 184-185, DOI: 10.5852/ejt.2013.48, http://zenodo.org/record/3822836

Ophiochondrus punctatus (Kutscher & Jagt, 2000) comb. nov. Fig. 37: 4-5 Ophiacantha ? punctata Kutscher & Jagt, 2000: 62-63, pl. 25 figs 3-5. Diagnosis Species of Ophiochondrus with small LAPs displaying a coarsely meshed stereom on the outer surface with trabecular intersections strongly thickened into slightly vertically elongate granules or knobs; small, very poorly defined, weakly prominent and protruding spur on the outer proximal edge, paralleled on the inner distal edge by a moderately well-defined, rounded area of densely meshed stereom; up to eight small, slightly oval, spine articulations, proximally bordered by thick, slightly knobby ridge; gap between spine articulations and distal edge of LAP with trabecular intersections thickened into small granules; ridge on inner side relatively small, short. Material examined GZG.INV.78775, GZG.INV.78776 and 260 dissociated LAPs in the Manfred Kutscher Collection in Sassnitz, Germany, the type material of Kutscher & Jagt (2000). Description Small, dissociated LAPs, proximal ones slightly higher than wide, distal ones approximately 1.5 times wider than high; proximal to median LAPs of massive, thick, rounded aspect; dorsal edge straight (proximal LAPs) to concave (median and distal LAPs) as a result of a well-developed constriction; distal edge convex; proximal edge nearly straight, with small, very poorly defined, weakly prominent and very slightly protruding spur ventrally bordered by small, poorly defined, non-depressed area of slightly more finely meshed stereom; outer surface with coarsely meshed stereom slightly fining towards proximal edge; trabecular intersections of coarsely meshed stereom thickened into large, very weakly vertically elongate granules or knobs. Eight (proximal LAPs) to six (distal LAPs) small, ear-shaped, slightly oval spine articulations freestanding on weakly to fairly elevated distal portion of LAP; spine articulations proximally bordered by thick, well-defined, knobby ridge composed of vertically merged thickened trabeculae of coarsely meshed outer surface stereom; ventral and dorsal lobes of spine articulations separated proximally by very small notch; spine articulations nearly of equal size or with very weak dorsalward decrease in size; gap between spine articulations and distal edge of LAP at most as wide as one spine articulation, with dorsalward increase in width, with trabecular intersections of moderately finely meshed stereom thickened into small granules. Ventral edge of LAP weakly concave; tentacle notch invisible in external view. Inner side of LAPs with relatively small, short, well-defined, prominent ridge with ventro-proximalwards bent ventral part not merged with ventral portion of LAP; dorsal tip of ridge slightly widened, with short ventro-proximalwards projecting extension; small, round knob distally bordering ridge in distal LAPs; inner side of distal edge of proximal to median LAPs with relatively small, moderately well-defined, round, very weakly protruding area of more densely meshed stereom; inner side of tentacle notch very small, shallow, moderately well defined laterally. No perforations or furrow discernible. Remarks Kutscher & Jagt (2000) described this LAP type from the early Maastrichtian of Germany and Denmark in detail and tentatively assigned it to Ophiacantha using open nomenclature. They stressed, however, that this assignment was highly doubtful when the fossil LAPs were compared with those of extant species of Ophiacantha. Thanks to a systematic SEM-supported assessment of LAP morphologies in Recent ophiacanthids performed in the course of the present study, it is now possible to constrain the generic placement of these LAPs even further. Strongest similarities are shared with the LAPs of Ophiochondrus, mainly on account of the massive, thick, rounded general aspect of the LAPs, the shape, size and position of the spine articulations, the outer surface ornament, and the shape of the ridge on the inner side. It is the first fossil record of Ophiochondrus or at least of a very closely related, extinct genus. The LAPs of Ophiochondrus punctatus comb. nov. cannot be confused with any other fossil type of LAP. Those of co-occurring Ophiochondrus ? semirotundus (Kutscher & Jagt, 2000) comb. nov. have fewer spine articulations not bordered proximally by a ridge, and large contact surfaces with the opposite LAP on the inner side. LAPs assigned to Inexpectacantha display strongly tilted spine articulations with a ventral lobe commonly merged with the outer surface stereom, and a ridge on the inner side lacking the ventro-proximalwards projecting extension. Occurrence Early Maastrichtian of Germany and Denmark., Published as part of Thuy, Ben, 2013, Temporary expansion to shelf depths rather than an onshore-offshore trend: the shallow-water rise and demise of the modern deep-sea brittle star family Ophiacanthidae (Echinodermata: Ophiuroidea), pp. 1-242 in European Journal of Taxonomy 48 on pages 209-211, DOI: 10.5852/ejt.2013.48, http://zenodo.org/record/3822836, {"references":["Kutscher M. & Jagt J. W. M. 2000. Early Maastrichtian ophiuroids from Rugen (northeast Germany) and Mon (Denmark). In: Jagt J. W. M. 2000. Late Cretaceous-Early Palaeogene echinoderms and the K / T boundary in the southeast Netherlands and the northeast Belgium - Part 3: Ophiuroids. Scripta Geologica 121: 45 - 107.","Hess H. 1966. Mikropalaontologische Untersuchungen an Ophiuren V: Die Ophiuren aus dem Argovien (unteres Ober-Oxford) vom Guldental (Kt. Solothurn) und von Savigna (Dept. Jura). Eclogae geologicae Helvetiae 59: 1025 - 1063."]}

Genus Ophiacantha Müller & Troschel, 1842 Type species Ophiacantha spinulosa Müller & Troschel, 1842 [junior synonym of Ophiacantha bidentata (Bruzelius, 1805)], by original designation. Diagnosis LAPs with dorsal and ventral lobes of spine articulations fused into continuous volute; ventral part of LAPs not protruding ventro-proximalwards; generally no more than one spur on the outer proximal and inner distal edges; ridge on inner side composed of long, oblique, straight to slightly bent main part with a pointed dorsal tip and with ventrally pointing, vertical to slightly oblique or bent extension generally at least as long as half of the main part; in many cases, main part and ventrally pointing extension fused into large, irregularly triangular knob; tentacle notch small. Remarks Ophiacantha is one of the most speciose (Stöhr et al. 2012), but also one of the most heterogeneous genera among the extant ophiuroids (O’Hara & Stöhr 2006). This morphological heterogeneity is also reflected in LAP morphology, as already pointed out by Thuy & Stöhr (2011), with some species sharing greater similarities in LAP morphology to species of other ophiacanthid genera than with their congeners. Thus, working out a comprehensive and at the same time meaningful LAP morphological diagnosis of Ophiacantha is a major challenge. To make matters worse, most characters observed in the LAPs of Ophiacantha also occur in other genera. The most stringent approach is to focus on the LAP morphology of the type species, Ophiacantha bidentata, on the basis of which the LAP morphologies of the other species are assessed. The LAPs of O. bidentata were described in detail and illustrated by Thuy & Stöhr (2011). They are characterised by a ridge on their inner side, which consists of a main oblique, straight to slightly proximally bent part with a pointed dorsal tip and fused dorsally to a ventrally pointing, near-vertical to slightly oblique extension close to the proximal edge of the LAP longer than half of the main part of the ridge. In some cases, the main part of the ridge and its ventrally pointing dorsal extension are merged into a single, large, irregularly triangular knob. In combination with the large ear-shaped spine articulations on a strongly elevated distal portion of the LAP, with dorsal and ventral lobes merged into a continuous volute, and proximally sharply bordered by the distalmost lamella of a well-developed vertical striation on part of the outer surface, the shape of this ridge is distinctive. This is important to note since slightly modified versions of ridge shape are also found in other, not necessarily closely related ophiacanthids (e.g. Ophiomitrella Verrill, 1899; Ophioplinthaca Verrill, 1899, “ Ophiophthalmus ” Matsumoto, 1917). Many species of Ophiacantha share the above-mentioned combination of features, which can be thus considered as the Ophiacantha LAP morphology in its proper sense. Whether the species in question also share similar general skeletal morphologies, and thus potentially represent a true clade with the Ophiacanthidae, remains to be investigated. A number of extant species of Ophiacantha conflict with the type species in terms of LAP morphology. Particularly striking is the occurrence in a number of species of Ophiacantha of a ridge shape otherwise exclusively found in Ophiotreta and Ophiopristis. The species in question include Ophiacantha anomala G.O. Sars, 1872, O. rosea Lyman, 1878, O. spectabilis G.O. Sars, 1872 and O. vivipara Ljungman, 1872. Remarkably, these four species are known to have closely similar general skeletal morphologies in common (Paterson 1985; O’Hara & Stöhr 2006), thus most probably form a phylogenetically consistent group. A detailed reassessment of the species in question is likely to result in separation at the generic level, which would gain support from evidence of LAP morphology. Other species currently assigned to Ophiacantha differ from the type species in displaying generally lower LAPs (smaller height/width ratios), proximally separated dorsal and ventral lobes of the spine articulations which thus become slightly horizontally elongate rather than round, a single protruding spur in the middle of the outer proximal and inner distal edges, and a densely meshed or even granulated stereom covering the outer surface rather than a vertical striation. At the same time, they share the highly distinctive shape of the ridge on the inner side with Ophiacantha bidentata. Such taxa include Ophiacantha smitti Ljungman, 1872, O. pentagona Koehler, 1897, O. prionota H.L. Clark, 1911 and O. levispina Lyman, 1878. Whether this grouping is artificial or, indeed, reflects general skeletal morphological similarities is in need of further study. Remarkably, the species in question are closer to species of Ophiolebes Lyman, 1878 in terms of LAP morphology than to their congeners. According to the revised cladistic phylogeny presented here, Ophiacantha is sister taxon to the Ophiolebes - Ophialcaea clade. Unfortunately, LAPs of extant species of Ophialcaea Verrill, 1899 could not be examined using the standards set by Thuy & Stöhr (2011). Ophiolebes, however, is shown here to share largely similar LAP morphologies with Ophiacantha, in particular with the species mentioned above.Similar to those of the latter, the LAPs of Ophiolebes display a ridge that is superficially comparable to the one seen in Ophiacantha bidentata. The main distinction between the LAPs of Ophiolebes and those of O. bidentata and similar congeners are the proximally separated dorsal and ventral lobes of the spine articulations. To conclude, as currently understood, the genus Ophiacantha obviously unites a number of fundamentally different LAP morphologies, some of which definitely reflect differences at the generic level to be worked out in detail by future studies. It is very difficult to characterise the LAP morphology of the genus convincingly, even if restricted to the type species and species with morphologically similar LAPs. The ridge shape described above for Ophiacantha bidentata, along with spine articulations freestanding on the elevated distal edge of the LAP, with dorsal and ventral lobes fused into a continuous volute, and bordered proximally by a not exceedingly thickened distalmost lamella is a combination which probably comes closest to a diagnosis of the LAP morphology of Ophiacantha in its proper sense. For the purpose of the present, only fossil LAPs displaying this combination of characters are assigned to Ophiacantha.

Dermacantha pattyana sp. nov. urn:lsid:zoobank.org:act: 4F9EF5AE-AF42-4815-B870-EF9964CEAEC8 Fig. 29: 2-5 Diagnosis Species of Dermacantha gen. nov. with small LAPs displaying a very finely meshed stereom on the outer surface; trabeculae of outer surface stereom merging into very poorly developed, irregular vertical striation close to spine articulations; two very weakly defined spurs on the outer proximal and inner distal edges; up to four relatively small spine articulations; ridge on inner side relatively short and wide. Etymology Species named in honour of my friend and near-sister Patty Muller. Type material Holotype MnhnL HE414. Paratypes MnhnL HE415, MnhnL HE416 and MnhnL HE417. Type locality and horizon Fontenoille, Belgium; level c of Delsate et al. (2002), Liasicus Zone, Hettangian, Early Jurassic. Additional material MnhnL HE418 (294 dissociated LAPs). Description Holotype MnhnL HE414 is a dissociated, small,proximal to median LAP; nearly as high as wide;dorsal edge straight; distal edge convex; proximal edge irregularly concave, with two large, poorly defined, horizontally elongate and weakly prominent spurs, ventral one slightly larger and more strongly protruding; ventral sixth of LAP slightly protruding ventro-proximalwards; outer surface with very finely meshed stereom; trabeculae of outer surface stereom merging into very faint, poorly developed, irregular vertical striation close to spine articulations. Four relatively small, ear-shaped spine articulations sunken individually into moderately deep notches of the non-elevated distal LAP edge; ventral and dorsal lobes thin, separated by small knob proximally; spine articulations equal-sized and equi-distant; gap between spine articulations and distal edge of LAP moderately wide, slightly narrower than the width of one spine articulation, decreasing in width ventralwards. Ventral edge of LAP with small, concave tentacle notch. Inner side of LAP with well-defined, prominent, relatively broad, short ridge; dorsal tip of ridge slightly widened, tongue shaped, pointing dorso-proximalwards; ventral part of ridge merged with thickened ventral LAP portion; inner side of distal edge with two medium-sized, poorly defined, oval, weakly prominent spurs; inner side of ventro-distal tip of LAP thickened; inner side of tentacle notch moderately large, sharply defined laterally. No perforations or furrow discernible. Paratype supplements and variation MnhnL HE415 is a dissociated proximal LAP; ventral portion missing; LAP originally higher than wide; generally well in agreement with holotype; dorsal edge oblique, slightly convex; two spurs on proximal edge very weakly defined; ventro-distal tip of LAP strongly protruding ventro-distalwards, tongue shaped; trabeculae of very finely meshed stereom on outer surface not merging into vertical striation. Four spine articulations similar to those observed on holotype. Ridge on inner side of LAP slightly narrower and longer than that of holotype, almost vertical dorsally. MnhnL HE416 is a dissociated median LAP; slightly higher than wide; spurs on outer proximal edge very poorly defined; ventro-distal tip of LAP very slightly protruding ventro-distalwards, rounded; trabeculae of outer surface stereom more commonly merging into vertical striation than in holotype; vertical striation better developed and more widespread rather than restricted to a very narrow band near the spine articulations. Four spine articulations similar to those observed in holotype; gap between spine articulations and distal edge of LAP narrower than in holotype; ventralmost spine articulation smaller than remaining three. Inner side of LAP similar to that of holotype. MnhnL HE417 is a dissociated distal LAP; approximately 1.5 times wider than high; poorly preserved; dorsal edge very slightly concave; spurs on proximal edge very poorly defined, almost indiscernible; only very few trabeculae of finely meshed outer surface stereom merged into poorly developed vertical striation. Two poorly preserved spine articulations apparently similar to those observed on holotype. Ventral edge of LAP nearly straight, with small, weakly concave tentacle notch. Inner side with small, well-defined, nearly triangular, oblique ridge, with dorso-proximally pointing dorsal tip; ventral part widest, not merged with ventral portion of LAP; spurs on inner side of distal edge of LAP almost indiscernible. Remarks These LAPs are unambiguously assignable to Dermacantha gen. nov. on account of the general Dermocoma -like morphology with smaller spine articulations displaying a discontinuous volute. Greatest similarities are shared with the LAPs of Dermacantha seeweni comb. nov., which, however, display a better-developed vertical striation on the outer surface, only one poorly defined spur, and up to five spine articulations with a conspicuously distalwards projecting ventral lobe. Occurrence Hettangian of Belgium., Published as part of Thuy, Ben, 2013, Temporary expansion to shelf depths rather than an onshore-offshore trend: the shallow-water rise and demise of the modern deep-sea brittle star family Ophiacanthidae (Echinodermata: Ophiuroidea), pp. 1-242 in European Journal of Taxonomy 48 on pages 162-164, DOI: 10.5852/ejt.2013.48, http://zenodo.org/record/3822836, {"references":["Delsate D., Duffin C. J. & Weis R. 2002. A new microvertebrate fauna from the Middle Hettangian (Early Jurassic) of Fontenoille (Province of Luxembourg, south Belgium). Memoirs of the Geological Survey of Belgium 48, Royal Belgian Institute of Natural Sciences, Brussels."]}

Ophiotreta striata (Kutscher & Jagt, 2000) comb. nov. Fig. 17: 1-2 Ophiacantha ? striata Kutscher & Jagt, 2000: 64, pl. 25 figs 8-10. non Ophiacantha? aff. striata – Štorc & Žítt 2008: 128, fig. 4L-M. Diagnosis Species of Ophiotreta with large LAPs, displaying up to ten nearly equal-sized spine articulations; very weak connecting ridge between ventral lobe of spine articulations and distalmost lamella of outer surface striation in all LAPs, including the median and distal ones; no spurs on outer proximal and inner distal LAPs. Material examined GZG.INV.78588, GZG.INV.78589 and 216 dissociated LAPs from the Manfred Kutscher Collection in Sassnitz, Germany, the type material of Kutscher & Jagt (2000); 2 dissociated LAPs from the early Maastrichtian of Lägerdorf-Kronsmoor, Germany. Description Dissociated moderately large LAPs, more than twice higher than wide (proximal ones) to slightly wider than high (distal LAPs); dorsal edge mostly straight to slightly concave as a result of a weak constriction; distal edge convex; proximal edge irregularly undulose, devoid of spurs; outer surface with vertical striation composed of broad, slightly overlapping lamellae restricted to the proximal edge of the strongly elevated distal portion of proximal LAPs, extending into middle of outer surface in median to distal LAPs; lamellae becoming finer proximally and replaced by moderately finely meshed stereom towards proximal edge of LAP. Ten (proximal LAPs) to five (distal LAPs) large, ear-shaped spine articulations on strongly elevated distal portion of LAPs; dorsal lobe of spine articulations very large, separated from smaller ventral lobe by small, moderately deep notch; spine articulations proximally sharply delimited by thin, slightly undulose distalmost lamella; very weakly defined, slightly prominent connecting ridge between ventral lobes of spine articulations and distalmost lamella; very weak dorsalward increase in size of spine articulations and of gaps separating them. Ventral edge of LAP straight to slightly convex; tentacle notch generally invisible in external view. Inner side of LAPs with large, conspicuous, sharply defined yet narrow ridge composed of very long, straight, near-vertical dorsal portion very close to the proximal edge of the lap; and shorter and slightly wider, straight, oblique ventral portion with slightly more prominent rounded ventral tip; ventral and dorsal portions of ridge separated by sharp kink with ventro-proximally pointing angle; small, round, sharply defined, prominent knob on ventral portion of inner side, widely separated from ridge; inner side of distal edge of LAP devoid of spurs; inner side of tentacle notch moderately large. Vertical row of very small, seemingly irregularly spaced perforations in very shallow, poorly defined furrow dorsally bordering inner side of tentacle notch. Remarks The dissociated LAPs from the early Maastrichtian of Germany and Denmark, on the basis of which Kutscher & Jagt (2000) described the new species, Ophiacantha ? striata, are unequivocally assignable to the Ophiotreta - Ophiopristis group mainly on account of the highly distinctive shape of the ridge on the inner side. The connecting ridges between the ventral lobe of the spine articulations and the distalmost lamella of the outer surface striation are weakly developed in this species, which makes assignment to Ophiopristis equally probable. It is of prime importance here to recall that the LAP morphologies of Ophiopristis and Ophiotreta are almost indistinguishable. In view of the fact that a species can only be assigned to a single genus, Ophiotreta is preferred here, for reasons outlined above in the discussion of the genus. This generic placement is likely to change as soon as more will be known of the general skeletal morphology of Ophiotreta striata comb. nov., but also following a systematic reappraisal of extant species of Ophiotreta and Ophiopristis. Among the fossil LAPs assigned to Ophiotreta, O. striata comb. nov. is unambiguously characterised by the lack of spurs on the outer proximal edge and the high number of spine articulations. The closest resemblance is with Ophiotreta dendrophyllicola sp. nov. in which, however, the median and distal LAPs display a small, protruding spur on the outer proximal edge, and better-developed connecting ridges between the spine articulations and the outer surface. The LAPs from the Turonian of the Czech Republic described as Ophiacantha ? aff. striata by Štorc & Žítt (2008) are most probably assignable to Ophiotreta. Their slightly better-developed connecting ridge suggests that they belong to an undescribed species close to O. striata comb. nov. Occurrence Early Maastrichtian of Germany and Denmark., Published as part of Thuy, Ben, 2013, Temporary expansion to shelf depths rather than an onshore-offshore trend: the shallow-water rise and demise of the modern deep-sea brittle star family Ophiacanthidae (Echinodermata: Ophiuroidea), pp. 1-242 in European Journal of Taxonomy 48 on pages 88-90, DOI: 10.5852/ejt.2013.48, http://zenodo.org/record/3822836, {"references":["Kutscher M. & Jagt J. W. M. 2000. Early Maastrichtian ophiuroids from Rugen (northeast Germany) and Mon (Denmark). In: Jagt J. W. M. 2000. Late Cretaceous-Early Palaeogene echinoderms and the K / T boundary in the southeast Netherlands and the northeast Belgium - Part 3: Ophiuroids. Scripta Geologica 121: 45 - 107.","Storc R. & Zitt J. 2008. Late Turonian ophiuroids (Echinodermata) from the Bohemian Cretaceous Basin, Czech Republic. Bulletin of Geosciences 83 (2): 123 - 140. http: // dx. doi. org / 10.3140 / bull. geosci. 2008.02.123"]}

Ophiochondrus ? semirotundus (Kutscher & Jagt, 2000) comb. nov. Fig. 37: 6-7 Ophiothela ? semirotunda Kutscher & Jagt, 2000: 74-75, pl. 29 figs 11-13. Diagnosis Species tentatively assigned to Ophiochondrus with small, massive, rounded and thick LAPs displaying a coarsely granular outer surface; proximal edge slightly thickened, separated from the remaining outer surface by a shallow, moderately well-defined furrow; no spurs discernible on outer proximal and inner distal edges; up to six small, oval, horizontally elongate spine articulations on bulging distal portion of LAP; inner side of LAP with small, rather poorly defined ridge displaying weakly widened dorsal tip; large dorsal and ventral contact surfaces with opposite LAP facing midline of arm. Material examined GZG.INV.78800, GZG.INV.78801 and 32 dissociated LAPs in the Manfred Kutscher Collection in Sassnitz, Germany, the type material of Kutscher & Jagt (2000). Description Small, dissociated LAPs, proximal ones slightly higher than wide, distal ones slightly wider than high; of rounded, massive, thick aspect; dorsal edge slightly concave as a result of a constriction; distal edge convex; proximal edge nearly straight to slightly convex, with proximally protruding ventro-proximal tip; proximal edge slightly thickened, separated from remaining outer surface by shallow, moderately well-defined furrow; no spurs on proximal edge; outer surface with moderately coarsely granular stereom even between spine articulations and on thickened part of proximal edge; granules on outer surface with weak tendency to merge into short, knobby, irregular vertical ridges. Six (proximal LAPs) to five (distal LAPs) small, equal-sized and nearly equi-distant, ear-shaped, oval, horizontally elongate spine articulations freestanding on bulging distal portion of LAP; not bordered proximally by a ridge; dorsal and ventral lobes nearly horizontal, separated proximally; gap between spine articulations and distal edge of LAP as wide as half a spine articulation; row of spine articulations slightly oblique, dorsoproximalwards receding. Ventral edge of LAPs convex; tentacle notch invisible in external view. Inner side of LAPs with small, short, poorly defined, prominent, inconspicuous ridge, with ventroproximalwards bent, slightly widened ventral part not merged with ventral portion of LAP; dorsal tip of ridge slightly widened, no extension discernible; inner side of distal edge of LAP devoid of spurs; inner side of tentacle notch very small, moderately well defined laterally, shallow; dorsal, ventral and ventro-proximal edges facing midline of arm with large, vertical contact surfaces. No perforations or furrow discernible. Occurrence Early Maastrichtian of Germany and Denmark. Remarks This LAP type from the Early Maastrichtian of Germany and Denmark was first described by Kutscher & Jagt (2000) as Ophiothela ? semirotunda. Assignment to the ophiotrichid genus Ophiothela Verrill, 1867 is untenable considering the fundamental differences in spine articulation morphology (Martynov 2010). Interestingly, Kutscher & Jagt (2000) mentioned that their new species showed a certain resemblance to small-sized ophiacanthids, and later primarily compared it to LAP types originally assigned to hemieuryalids (here reinterpreted as species of the ophiacanthid Inexpectacantha; see above). Indeed, the presence of a sigmoidal fold in the spine articulations unambiguously places the LAPs in question in the Ophiacanthidae. A comparison with the LAPs of Recent ophiacanthids reveals that closest similarities are shared with the LAPs of Ophiochondrus, in particular on account of the generally round, massive and stout aspect, the size, shape and position of the spine articulations, and the outer surface ornament. Significant differences, however, can be found in the structure of the inner side. In fact, these fossil LAPs display large contact surfaces with the opposite LAP, facing the midline of the arm. Such contact surfaces are commonly found in species of the ophiolepidid genus Ophiomusium Lyman, 1869 (e.g. Kutscher & Jagt 2000), but are atypical of Ophiochondrus. This difference is very likely to warrant separation at the generic level. However, as long as the inner side of the LAPs of Ophiomoeris remains unknown, assignment to this genus cannot be ruled out. At the present state of knowledge, it thus seems best to tentatively assign the present LAPs to Ophiochondrus, stressing, however, that there are significant differences in LAP morphology between the fossil LAPs and those of Recent Ophiochondrus, in particular the type species of the genus., Published as part of Thuy, Ben, 2013, Temporary expansion to shelf depths rather than an onshore-offshore trend: the shallow-water rise and demise of the modern deep-sea brittle star family Ophiacanthidae (Echinodermata: Ophiuroidea), pp. 1-242 in European Journal of Taxonomy 48 on pages 211-212, DOI: 10.5852/ejt.2013.48, http://zenodo.org/record/3822836, {"references":["Kutscher M. & Jagt J. W. M. 2000. Early Maastrichtian ophiuroids from Rugen (northeast Germany) and Mon (Denmark). In: Jagt J. W. M. 2000. Late Cretaceous-Early Palaeogene echinoderms and the K / T boundary in the southeast Netherlands and the northeast Belgium - Part 3: Ophiuroids. Scripta Geologica 121: 45 - 107.","Martynov A. 2010. Reassessment of the classification of the Ophiuroidea (Echinodermata), based on morphological characters. I. General character evaluation and delineation of the families Ophiomyxidae and Ophiacanthidae. Zootaxa 2697: 1 - 154."]}

Genus Dermacantha gen. nov. urn:lsid:zoobank.org:act: D73D5436-6A0A-43C1-8298-C5C4BE5D5CA3 Type species Dermacantha leonorae sp. nov., by present designation. Other species included Dermacantha pattyana sp. nov., Ophiocten ? seeweni Kutscher & Hary, 1991 and Dermacantha carli sp. nov. Diagnosis Ophiacanthid with small to moderately large LAPs; small height/width ratio, even in proximal LAPs; relatively few (up to five) small spine articulations in notches of slightly elevated distal portion of LAP; ventral and dorsal lobes of spine articulations proximally separated by small knob; ventral portion of LAP generally strongly protruding ventro-proximalwards; up to two poorly to well-defined spurs on outer proximal and inner distal edges; inner side of LAPs with simple, slender ridge devoid of sharp kinks or strongly thickened parts; tentacle notch small. Etymology Name composed of derma, Greek for “skin”, and Acantha, a nymph in Greek mythology whose name literally translates as “thorny”, in reference to the striking similarities in LAP morphology shared with Dermocoma. Remarks The ophiacanthid fossil record includes a number of dissociated LAP types which, at first sight, seem compatible with the LAP morphological diagnosis of Dermocoma, in particular with respect to the strongly protruding ventral portion of the LAPs, the position of the spine articulations, the presence of spurs on the outer proximal and inner distal edges and the shape of the ridge on the inner side. The spine articulation morphology, however, differs markedly. In fact, while the LAPs of Dermocoma display spine articulations with a continuous volute, those of the LAP type in question have the ventral and dorsal lobes proximally separated by one or several small knobs. This significant difference is generally combined with a smaller height/width ratio, even in proximal LAPs, and with smaller spine articulations than in Dermocoma. Since these differences co-occur consistently, Dermacantha gen. nov. is introduced here to accommodate the Dermocoma -like LAP types with small spine articulations displaying a discontinuous volute. The striking similarities in LAP morphology, however, strongly suggest that Dermocoma and Dermacantha gen. nov. share close phylogenetic ties, as suggested by the name of the new genus. Superficial similarities are shared with the LAPs of Lapidaster gen. nov. with respect to the weakly elevated distal portion of the LAPs and the spurs on the outer proximal and inner distal edges. In Lapidaster gen. nov., however, the spine articulations are never sunken into notches of the distal LAP portion, and the tentacle notch generally is much larger., Published as part of Thuy, Ben, 2013, Temporary expansion to shelf depths rather than an onshore-offshore trend: the shallow-water rise and demise of the modern deep-sea brittle star family Ophiacanthidae (Echinodermata: Ophiuroidea), pp. 1-242 in European Journal of Taxonomy 48 on pages 160-162, DOI: 10.5852/ejt.2013.48, http://zenodo.org/record/3822836, {"references":["Kutscher M. & Hary A. 1991. Echinodermen im Unteren Lias (Bucklandi- und Semicostatum-Zone) zwischen Ellange und Elvange (SE-Luxemburg). Neues Jahrbuch fur Geologie und Palaontologie, Abhandlungen 182: 37 - 72."]}

Ophiogaleus dorecki (Hess, 1962) comb. nov. Fig. 20: 1-2 p.p. Ophiacantha? dorecki Hess, 1962: 622 , figs 17, 19 (fig. 18 is a different species, probably not even an ophiacanthid). non Ophiacantha? cf. dorecki – Kutscher 1996: 18, pl. 4, fig. 5 (probably an ophiomycetid close to extant Ophiohelus Lyman, 1880). Diagnosis Species of Ophiogaleus gen. nov. with relatively large LAPs displaying up to eleven spine articulations on the strongly elevated, yet proximally not sharply bordered, distal portion; no spurs discernible on outer proximal edge; up to three small, well-defined, strongly prominent spurs on inner distal edge of the LAP; ridge on the inner side with relatively narrow but vertically extremely elongate dorsal part. Material examined NHMB M1214, NHMB M 1215 and 35 dissociated LAPs from the late Pliensbachian of Seewen, Switzerland, the type material of Hess (1962). Description Large LAPs; proximal ones more than twice higher than wide; distal ones nearly as high as wide; dorsal edge slightly concave as a result of a moderately well-developed constriction; distal edge convex; proximal edge irregularly undulose, no spurs discernible; outer surface with moderately finely meshed stereom, replaced by more finely meshed stereom in very narrow band paralleling proximal edge of LAP. Eleven (proximal LAPs) to seven (distal LAPs) large, ear-shaped spine articulations freestanding on strongly elevated distal portion of LAP; dorsal and ventral lobes of spine articulations merged into continuous volute; spine articulations not sharply bordered proximally; relatively narrow gap between spine articulations and distal edge of LAP; moderate (proximal LAPs) to weak (median and distal LAPs) dorsalward increase in size of spine articulations and of gaps separating them; row of spine articulations strongly (proximal LAPs) to weakly (distal ones) protruding ventralwards. Tentacle notch invisible in external view. Inner side of LAPs with large, conspicuous, sharply defined, prominent ridge; short oblique central part of ridge; dorsal part widened, strongly vertically elongate, nearly triangular, with pointed (in proximal LAPs extremely elongate) dorsal tip, ventro-proximal tip slightly pointed; ventral portion of central part of ridge very short, ventro-proximally pointing, sharply separated from ventral part of LAP; inner side of distal edge of LAP with two to three small, well-defined, strongly prominent spurs composed of slightly more densely meshed stereom; inner side of tentacle notch relatively small, poorly defined laterally; moderately shallow, dorsally well-defined vertical furrow with small, irregular perforations dorsally bordering tentacle notch. Remarks Hess (1962) described the new species Ophiacantha ? dorecki on the basis of dissociated lateral arm plates from the Pliensbachian of Switzerland. A re-examination of the type material, however, has revealed that it actually includes two different LAP types, one similar to the holotype (see Hess 1962, fig. 17), the other resembling Hess’s (1962) fig. 18, characterised by a slightly oblique row of closely spaced spine articulations widely separated from the distal edge of the LAP. The higher-level taxonomic affinities of the latter type are unclear. Some features point to the Ophiacanthidae but the sigmoidal fold, one of the key diagnostic features of the family, could not be unambiguously observed in the specimens at hand. In contrast, the LAP type, including the holotype, unquestionably belongs to the Ophiacanthidae. Within this family, strongest affinities are shared with the LAPs of Ophiogaleus constrictus comb. nov. and O. danicus comb. nov., on account of the number, shape and position of the spine articulations and the number of spurs on the inner distal edge of the LAP. The shape of the ridge on the inner side of the type specimens of Hess (1962) is admittedly rather unusual for Ophiogaleus gen. nov., but nevertheless compatible with the LAP morphological diagnosis of the genus. Within this genus, the LAPs are unique in displaying up to eleven spine articulations, lacking a ridge sharply bordering the spine articulations proximally and in having a relatively narrow but vertically extremely elongate dorsal part of the ridge on the inner side. The LAPs described and illustrated by Kutscher (1996) as Ophiacantha ? cf. dorecki from the Toarcian/ Aalenian of Germany fundamentally differ from the type material of Hess (1962), in particular with respect to spine articulation morphology. The LAPs in question share greatest similarities with those of the extant ophiomycetid Ophiohelus. Occurrence Late Pliensbachian of Switzerland., Published as part of Thuy, Ben, 2013, Temporary expansion to shelf depths rather than an onshore-offshore trend: the shallow-water rise and demise of the modern deep-sea brittle star family Ophiacanthidae (Echinodermata: Ophiuroidea), pp. 1-242 in European Journal of Taxonomy 48 on pages 110-112, DOI: 10.5852/ejt.2013.48, http://zenodo.org/record/3822836, {"references":["Hess H. 1962. Mikropalaontologische Untersuchungen an Ophiuren II: Die Ophiuren aus dem Lias (Pliensbachien-Toarcien) von Seewen (Kt. Solothurn). Eclogae geologicae Helvetiae 55: 609 - 656.","Kutscher M. 1996. Echinodermata aus dem Ober-Toarcium und Aalenium Deutschlands II. Ophiuroidea. Stuttgarter Beitrage zur Naturkunde Serie B 242: 1 - 33.","Hess H. 1966. Mikropalaontologische Untersuchungen an Ophiuren V: Die Ophiuren aus dem Argovien (unteres Ober-Oxford) vom Guldental (Kt. Solothurn) und von Savigna (Dept. Jura). Eclogae geologicae Helvetiae 59: 1025 - 1063."]}

Dermacantha leonorae sp. nov. urn:lsid:zoobank.org:act: 95EF2CA2-C31C-415F-A639-417842B0EEC6 Fig. 29: 9-11 Diagnosis Species of Dermacantha gen. nov. with small LAPs; proximal to median ones devoid of vertical striation on outer surface; five small spine articulations; single moderately well-defined spur near outer ventroproximal and inner ventro-distal tips of LAP; ridge on inner side very narrow but with strongly widened dorsal tip. Etymology Species named in hoinour of my friend and colleague Leonora Martín-Medrano, for her extraordinary hospitality and as an encouragement to her to pursue research in ophiuroid palaeontology. Type material Holotype GZG.INV.78710. Paratypes GZG.INV.78711 and GZG.INV.78712. Type locality and horizon Blockley, near Cheltenham, Great Britain; shell lenses in clay matrix, Davoei Zone, early Pliensbachian, Early Jurassic. Additional material GZG.INV.78713 (7 dissociated LAPs). Description Holotype GZG.INV.78710 is a dissociated, small, proximal LAP; slightly higher than wide; dorsal edge gently convex; distal edge convex; proximal edge concave, with single, moderately well-defined, prominent, horizontally elongate spur close to ventro-proximal tip of LAP; ventral sixth of LAP protruding ventroproximalwards; outer surface with very finely meshed stereom; no vertical striation; narrow band of very finely horizontally striated stereom along proximal edge. Five small, ear-shaped spine articulations in notches of non-elevated distal edge; dorsal and ventral lobes separated by small, thin knob; spine articulations proximally directly encompassed by outer surface stereom; spine articulations nearly of equal size; dorsalward increase in size of gaps separating spine articulations; gap between spine articulations and distal edge of LAP very narrow. Ventral edge of LAP with moderately large, very gently concave tentacle notch. Inner side of LAP with moderately large, conspicuous, sharply defined, prominent, very narrow ridge; dorsal tip strongly enlarged, nearly triangular; ventral part of ridge pointing ventro-proximalwards, not merged with slightly thickened ventral portion of LAP, separated from dorsal part of ridge by gentle, rounded kink; well-defined, oval, slightly prominent knob on ventro-distal tip of LAP; inner side of tentacle notch relatively large, with coarsely meshed, horizontally elongate stereom, well defined laterally. Very short and narrow, rather deep and well-defined furrow dorsally bordering tentacle notch. Paratype supplements and variation GZG.INV.78711 is a dissociated median LAP; slightly wider than high; very well in agreement with holotype; dorsal edge very slightly concave; spur near ventro-proximal tip of LAP sharply defined, lenticular, strongly prominent, composed of more densely meshed stereom. Five spine articulations similar to those observed on holotype; dorsalward increase in size of gaps separating spine articulations slightly weaker; ventral and dorsal lobes of spine articulations separated by one to three very small knobs. Inner side of LAP well in agreement with that of holotype; dorsal tip of ridge slightly less strongly widened. No furrow discernible. GZG.INV.78712 is a dissociated distal LAP; slightly wider than high; ventro-distal tip of LAP strongly protruding ventralwards, rounded; trabeculae of outer surface stereom merging into short, poorly developed, irregular vertical striation close to spine articulations. Four spine articulations similar to those observed on holotype; dorsalmost spine articulation smallest; gap between spine articulations and distal edge of LAP moderately large, widening ventralwards. Ventral edge of LAP with large, deeply concave tentacle notch. Inner side of LAP in agreement with that of holotype; dorsal tip of ridge slightly less strongly widened; spur on inner side of ventro-distal tip of LAP oblique. No furrow discernible. Remarks These LAPs are unambiguously assignable to Dermacantha gen. nov. on account of their spine articulation structure combined with the general Dermocoma -like morphology. They represent the sole LAP type within this genus which completely lacks a vertical striation on the outer surface. Closest similarities are shared with the LAPs of Dermacantha pattyana sp. nov., in particular those with reduced vertical striation on the outer surface. In the latter species, however, the ridge on the inner side is shorter and broader. Occurrence Early Pliensbachian of Great Britain., Published as part of Thuy, Ben, 2013, Temporary expansion to shelf depths rather than an onshore-offshore trend: the shallow-water rise and demise of the modern deep-sea brittle star family Ophiacanthidae (Echinodermata: Ophiuroidea), pp. 1-242 in European Journal of Taxonomy 48 on pages 165-166, DOI: 10.5852/ejt.2013.48, http://zenodo.org/record/3822836

Dermacantha sp. nov. innom. Fig. 30: 1-3 Material examined GZG.INV.78714, GZG.INV.78715, GZG.INV.78716 and GZG.INV.78717 (12 dissociated LAPs) from the Bajocian-Bathonian boundary of Touert near Chaudon, France. Description GZG.INV.78714 is a dissociated, moderately large, proximal LAP; nearly as high as wide; dorsal edge slightly concave as a result of a weak constriction; distal edge almost straight; ventral sixth of LAP ventroproximalwards protruding; proximal edge slightly undulose, with large, swollen, slightly protruding central part dorsally and ventrally bordered by small, well-defined, horizontally elongate, prominent spurs; outer surface with very fine, regular, vertical striation composed of fine, very weakly overlapping lamellae replaced by finely meshed stereom on proximal third of outer surface. Four relatively small, ear-shaped spine articulations in shallow notches of slightly elevated distal portion of LAP; ventral and dorsal lobes proximally separated by small knob; very weak connection between ventral lobe of spine articulations and distalwards projecting tips of outer surface stereom separating notches; spine articulations of nearly equal size, except for slightly smaller ventralmost one; very weak distalward increase in size of spine articulations; gap between spine articulations and distal edge of LAP narrow. Ventral edge of LAP with small, weakly concave tentacle notch. Inner side of LAP with relatively small, sharply defined, prominent, slender ridge; ventral half of ridge bent, pointing ventro-proximalwards, not merged with thickened ventral portion of LAP; dorsal half of ridge straight, oblique, with very weakly thickened dorsal tip; inner side of distal edge of LAP with two small, well-defined, prominent, oval, horizontally elongate spurs; inner side of tentacle notch small, laterally well defined. No perforations or furrow discernible. GZG.INV.78715 is a dissociated median LAP; 1.5 times wider than high; well in agreement with holotype; vertical striation restricted to a smaller area of the outer surface. Four equal-sized spine articulations similar to those observed on holotype; gap separating spine articulations and distal edge of LAP as wide as one spine articulation. Inner side similar to previous LAP described. GZG.INV.78716 is a dissociated distal LAP; almost twice wider than high; vertical striation on outer surface slightly less well developed than in holotype. Three equal-sized spine articulations similar to those of holotype; distal edge of LAP slightly fragmentary, width of gap between spine articulations and distal edge of LAP not determinable. Inner side of LAP with small, sharply defined, prominent, oblique, straight ridge; ventral tip of ridge widened. Remarks These LAPs, unambiguously assignable to Dermacantha gen. nov. on account of the general Dermocoma - like morphology combined with a discontinuous volute of the relatively small spine articulations, bear a striking similarity to the LAPs described below as Dermacantha carli sp. nov., to such an extent that both LAP types are almost indistinguishable. Minor differences pertain to the slightly thicker ventral portion and the slightly wider ridge in proximal LAPs of the present form. In addition, the vertical striation in the proximal LAPs of D. carli sp. nov. is composed of slightly larger, more strongly overlapping lamellae. Yet, these differences are so small that a formal description of the present specimens as a new species appears unjustified. To make matters worse, the amount of currently available material is too limited to appreciate fully the variability of the characters on which species separation would be based on. It seems unlikely that the present material is conspecific with D. carli sp. nov., in particular taking into account the long stratigraphic gap (Bajocian-Kimmerdigian) and the fundamentally different depositional settings (mud bottom slope versus deep shelf sponge reef) of both occurrences. In the absence of more diagnostic material, the present specimens are here treated as a probably new, still undescribed species of Dermacantha gen. nov., Published as part of Thuy, Ben, 2013, Temporary expansion to shelf depths rather than an onshore-offshore trend: the shallow-water rise and demise of the modern deep-sea brittle star family Ophiacanthidae (Echinodermata: Ophiuroidea), pp. 1-242 in European Journal of Taxonomy 48 on pages 166-167, DOI: 10.5852/ejt.2013.48, http://zenodo.org/record/3822836

Genus Ophiocamax Lyman, 1878 Type species Ophiocamax vitrea Lyman, 1878, by monotypy. Diagnosis Ophiacanthid with large to very large LAPs commonly devoid of any conspicuous outer surface ornament; single variably well-defined, protruding spur on outer proximal and inner distal edges; large to very large ear-shaped spine articulations freestanding on strongly elevated distal third or even half of the proximal and median LAPs, with especially the dorsal spine articulations commonly widely separated from distal edge of LAP; elevated portion of LAP commonly beset with scattered thorns or granules; dorsalmost spine articulation at some distance from dorsal edge of LAP, commonly pointing dorsalwards; dorsalmost and second dorsal spine articulations often much smaller than remaining ones; dorsal lobe of spine articulations with conspicuous central notch; ridge on inner side with strongly widened, generally short, triangular dorsal tip and evenly ventro-proximally bent ventral part; tentacle notch very small, deeply incised, well defined and generally at least semi circular. Remarks Ophiocamax is one of the most distinctive and homogeneous genera in the Ophiacanthidae, consistently displaying a number of characters not found in any other ophiacanthid. The same holds true for the LAPs of Ophiocamax (Fig. 35: 1-6), at least for the species examined herein with respect to their LAP morphologies, namely O. austera Verrill, 1899, O. fasciculata Lyman, 1883, O. hystrix Lyman, 1878 and the type species, O. vitrea. In fact, the LAPs of Ophiocamax display several highly distinctive features, including spine articulations freestanding in the middle of the strongly elevated distal third or even half of the LAPs and thus commonly widely separated from the distal edge of the LAP, dorsalwards pointing dorsalmost spine articulations well below the dorsal edge of the LAP, dorsalmost and second dorsal spine articulations which are often much smaller than the remaining ones, and a very small, welldefined and at least semi-circular tentacle notch. In addition, the dorsal lobe of the spine articulations of Ophiocamax displays a conspicuous central notch, which results in spine articulations that are seemingly composed of proximal and distal rather than dorsal and ventral lobes. The LAPs of extant Ophiomitra Lyman, 1869 (Fig. 34: 8-9), sister to Ophiocamax, share some important characters with the LAPs of the latter, in particular the spine articulations freestanding on the strongly elevated distal third or half of the LAP, the lack of a conspicuous outer surface ornament, and the strongly widened dorsal tip of the ridge on the inner side. In contrast to the LAP of Ophiocamax, however, those of Ophiomitra display nearly equal-sized spine articulations the dorsalmost of which commonly being very close to the dorsal edge of the LAP. In addition, the dorsal lobe of the spine articulation in Ophiomitra lacks the central notch. Thanks to the numerous highly distinctive characters, the LAPs of Ophiocamax are expected to be easily recognised in the form of dissociated fossil LAPs. Yet, only very few occurrences of dissociated LAPs and articulated arm fragments assignable to Ophiocamax are currently known from shallowwater settings, and all are from the Oxfordian. Another record from deep-sea deposits is noticeably fundamentally similar to the LAPs of extant Ophiocamax but differs in a few minor respects and is thus assigned to a new, most probably very closely related, genus, Reitneracantha gen. nov. (see below)., Published as part of Thuy, Ben, 2013, Temporary expansion to shelf depths rather than an onshore-offshore trend: the shallow-water rise and demise of the modern deep-sea brittle star family Ophiacanthidae (Echinodermata: Ophiuroidea), pp. 1-242 in European Journal of Taxonomy 48 on pages 198-199, DOI: 10.5852/ejt.2013.48, http://zenodo.org/record/3822836

Ophiacanthidae gen. et sp. nov. innom. Fig. 37: 8-9 Material examined GZG.INV.78802, GZG.INV.78803 and GZG.INV.78804 (dissociated LAPs) from the Bimammatum Zone, late Oxfordian, Late Jurassic of the Plettenberg, Germany. Description GZG.INV.78802 is a dissociated, tiny, proximal LAP; very fragile, dorso- and ventro-proximal tips missing; originally at least twice higher than wide; distal edge convex; outer surface with finely and moderately densely meshed stereom. At least six very large, densely spaced spine articulations freestanding on elevated distal portion of LAP; shape of spine articulations very unusual, complex; dorsal lobe very large, distally encompassing several openings of variable size; sigmoidal fold well developed but very short, proximally bordering very small nerve opening; ventral lobe very slender, proximally merged with dorsal lobe; spine articulations slightly oval, horizontally elongate; middle spine articulations largest, with dorsalward and ventralward decrease in size; spine articulations proximally sharply bordered by straight, well-defined but weakly prominent edge of elevated distal portion of LAP; gap between spine articulations and distal edge of LAP generally narrow, widest near middle spine articulations. No tentacle notch discernible in external view. Inner side of LAP with very slender, moderately well-defined, weakly prominent, oblique and nearstraight ridge with widened, vertically elongate dorsal tip composed of more finely meshed stereom; ventral tip of ridge indiscernible or poorly preserved; single, well-defined, prominent, oval spur composed of densely meshed stereom in ventral half of inner side of distal LAP edge; inner side of tentacle notch not preserved or indiscernible. No perforations or furrow discernible. GZG.INV.78803 is a dissociated median or distal LAP, strongly broken; outer surface with very densely meshed stereom. At least four very closely spaced spine articulations similar to those observed on the proximal specimen described above, displaying dorsalward increase in size; row of spine articulations ventrally bordered by very large, oblique, lenticular, round, strongly prominent ridge-like structure composed of dense stereom. Inner side of LAP with very slender, moderately well-defined, prominent ridge similar to the main part of the ridge observed on the previous specimen; ventral tip of ridge merged with large, well-defined, strongly prominent, oblique, elongate knob composed of densely meshed stereom; spur on inner side of distal edge of LAP much larger than in previous specimen; very large, round, lenticular, strongly prominent structure ventrally bordering row of spine articulations almost completely exposed in internal view. Remarks These specimens probably are among the most unusual ophiuroid LAPs ever recorded. The very weird, complex spine articulations display a sigmoidal fold, which suggests that the LAPs in question are assignable to the Ophiacanthidae. Affinities within this family, however, are purely speculative. These LAPs appear so highly derived that it is difficult, if not impossible, to deduce any phylogenetic relationships with other ophiacanthids on the basis of LAP morphology. It is even unfeasible to determine with certainty if this LAP type belongs to a large-pored or a small-pored ophiacanthid. To make matters worse, the material available is very limited and fragmentary, which hampers a proper systematic assessment of this highly intriguing LAP type. Striking similarities in the structure of the spine articulations are shared with the LAPs of the ophiocomid Ophiopteris papillosa Lyman, 1875. It cannot be ruled out that these similarities reflect close phylogenetic ties, which would place the present LAP type in the Ophiocomidae Ljungman, 1867. However, most of the other characters, in particular the size and fragility of the LAPs, the shape of the ridge on the inner side, the enigmatic structure ventrally bordering the row of spine articulations and the absence of perforations on the inner side, differ fundamentally. It thus seems more probable that the similarly shaped spine articulations were acquired independently. In the absence of more material, this LAP type cannot be formally described. It is clear, however, that it represents a new genus and species most probably assignable to the Ophiacanthidae. It is hoped that more material of this intriguing LAP type will be discovered in order to investigate its phylogenetic position and speculate on the function of the unusual spine articulation morphology and the enigmatic structure ventrally bordering the row of spine articulations., Published as part of Thuy, Ben, 2013, Temporary expansion to shelf depths rather than an onshore-offshore trend: the shallow-water rise and demise of the modern deep-sea brittle star family Ophiacanthidae (Echinodermata: Ophiuroidea), pp. 1-242 in European Journal of Taxonomy 48 on pages 213-214, DOI: 10.5852/ejt.2013.48, http://zenodo.org/record/3822836

Dermocoma simonschneideri sp. nov. urn:lsid:zoobank.org:act: D3449C2A-A9F1-42F1-87B0-CB8E0210232A Fig. 28: 5-8 Diagnosis Species of Dermocoma with large LAPs displaying a very well-developed vertical striation on at least half of the outer surface; large, oval and conspicuously oblique spur on proximal edge; four spine articulations sunken in deep notches of a poorly elevated distal LAP portion; ridge on inner side very slender, with ventral tip merged with ventral portion of LAP, and dorsal tip slightly widened and merged with proximal edge of LAP. Etymology Species named in honour of Simon Schneider, who kindly provided the samples yielding the type material of the species. Type material Holotype GZG.INV.78700. Paratypes GZG.INV.78701, GZG.INV.78702 and GZG.INV.78703 from the late Kimmeridgian (Late Jurassic) of Trancoso, Portugal. Type locality and horizon Pointe du Chay near La Rochelle, France; Achilles Subzone, Cymodoce Zone, early Kimmeridgian, Late Jurassic. Additional material GZG.INV.78704 (14 dissociated LAPs) from the Amaral Formation, late Kimmeridgian of Trancoso, Portugal. Description Holotype GZG.INV.78700 is a dissociated, large, proximal to median LAP; slightly higher than wide; dorsal and distal edges convex; proximal edge irregularly concave, with large, moderately well-defined, slightly prominent, non-protruding, oval and conspicuously oblique spur; ventral quarter of LAP strongly protruding ventro-proximalwards; distal half of outer surface with very well-developed, fine, regular vertical striation composed of overlapping lamellae, replaced by finely meshed stereom on proximal half of outer surface. Four relatively large, ear-shaped, nearly equal-sized spine articulations in deep notches of slightly elevated distal portion of LAP; ventral lobe merged with dorsal one into continuous volute but only weakly connected with distally projecting tip of outer surface between notches; spine articulations proximally sharply separated by edge of notches; weak dorsalward increase in size of gaps separating spine articulations; gap between spine articulations and distal edge of LAP very narrow. Ventral edge of LAP with small, weakly concave tentacle notch. Inner side of LAP with moderately large, very slender, gently bent ridge; ventral tip pointing ventralwards, merged with ventral portion of LAP; dorsal tip pointing dorso-proximally, slightly widened and merged with proximal edge of LAP; inner side of distal edge of LAP with small, well-defined, prominent, oval and oblique spur composed of densely meshed stereom; inner side of tentacle notch relatively large, with coarsely meshed, horizontally elongate stereom; well defined laterally. Short, shallow, rather broad, irregular and slightly oblique furrow with highly variable perforations dorsally bordering tentacle notch. Paratypes GZG.INV.78701 is a dissociated proximal LAP; approximately 1.5 times higher than wide; very well in agreement with holotype; outer surface less well defined, vertical striation not discernible. Four spine articulations similar to those of holotype. Inner side of LAP with ridge similar to that of holotype but slightly longer; spur on inner side of distal edge poorly defined. Short, slightly oblique furrow as in holotype but distally bordered by broad, poorly defined and weakly prominent ridge. GZG.INV.78702 is a dissociated median LAP; slightly wider than high; very well in agreement with holotype; vertical striation slightly finer and on distal two-thirds rather distal half of outer surface. Four spine articulations slightly smaller than those observed on holotype, otherwise similar. Ridge on inner side of LAP with more strongly widened dorsal tip; spur on inner side of distal LAP edge very poorly defined, almost indiscernible. No perforations or furrow discernible. GZG.INV.78703 is a dissociated distal LAP; more than 1.5 times wider than high; dorsal edge slightly concave as a result of a very weak constriction; proximal edge with two moderately well-defined spurs, dorsal one of which largest; vertical striation on three-quarters of outer surface. Four spine articulations smaller than those of holotype and poorly preserved, otherwise similar. Tentacle notch invisible in external view. Inner side of LAP with small, sharply defined ridge, with pointed, proximalwards bent dorsal tip, and widened ventral tip, not merged with ventral portion of LAP; inner side of distal edge of LAP with two poorly defined, large, oval, weakly prominent spurs; inner side of tentacle notch small, oblique, laterally well defined. Single, relatively large perforation dorsally bordering tentacle notch. Remarks In spite of the limited amount of material available, these LAPs are unambiguously assignable to the genus Dermocoma on account of the highly characteristic combination of the strongly protruding ventral portion of the LAP, the nearly equal-sized spine articulations in regularly spaced notches of the weakly elevated distal portion of the LAP, and the simple ridge on the inner side devoid of sharp kinks or conspicuously widened parts. The single large, conspicuously oblique spur on the outer proximal and inner distal edges of the proximal and median LAPs is a highly distinctive feature not found in any other species assigned to Dermocoma. Occurrence Early Kimmeridgian of France and late Kimmeridgian of Portugal., Published as part of Thuy, Ben, 2013, Temporary expansion to shelf depths rather than an onshore-offshore trend: the shallow-water rise and demise of the modern deep-sea brittle star family Ophiacanthidae (Echinodermata: Ophiuroidea), pp. 1-242 in European Journal of Taxonomy 48 on pages 156-158, DOI: 10.5852/ejt.2013.48, http://zenodo.org/record/3822836

Ophiacantha reginae sp. nov. urn:lsid:zoobank.org:act: 283B7CEB-644F-4997-A2FE-EFAED468A3BD Fig. 19: 3-5 Diagnosis Species of Ophiacantha with moderately large LAPs; outer surface stereom rather finely meshed, devoid of vertical striation; no spur on outer proximal and inner distal edges; up to seven spine articulations on strongly elevated distal portion of LAP; row of spine articulations strongly protruding dorsalwards. Etymology Species named in honour of Regina Fischer, who generously provided the sample yielding the type material of the species. Type material Holotype GZG.INV.78605. Paratypes GZG.INV.78606 and GZG.INV.78607. Type locality and horizon Alsen quarry, Lägerdorf, Germany; Galerites vulgaris Zone, late Campanian, Late Cretaceous. Additional material GZG.INV.78608 (one dissociated LAP). Description Holotype GZG.INV.78605 is a dissociated, moderately large, proximal LAP; slightly higher than wide; dorsal edge strongly concave as a result of a well-developed constriction; distal edge weakly convex; proximal edge concave, devoid of spurs; outer surface with moderately finely meshed stereom. Seven large, earshaped, round spine articulations on strongly elevated distal portion of LAP; very weak dorsalward increase in size of spine articulations and of gaps separating them; dorsal and ventral lobes of spine articulations merged into continuous, round volute; spine articulations proximally bordered by sharply defined, straight edge of strongly elevated distal portion of LAP; gap between spine articulations and distal edge of LAP from slightly narrower to clearly wider than one spine articulation, with dorsalward increase in width; row of spine articulations conspicuously protruding dorsalwards. Ventral edge of LAP convex, slightly pointed; tentacle notch invisible in external view. Inner side of LAP with large, well-defined, prominent ridge; main part of ridge straight, oblique, dorsal tip widened and merged with rather short ventrally projecting extension; ventral part of ridge slightly shorter than main part, gently bent, ventro-proximally bent, not merged with ventral portion of LAP; kink between ventral and main part of ridge rounded, slightly thickened; inner side of distal edge of LAP devoid of spurs; inner side of tentacle notch small, poorly defined, shallow. No perforations or furrow discernible. Paratype supplements and variation GZG.INV.78606 is a dissociated median LAP; nearly as high as wide; dorso-proximal tip slightly fragmentary; very well in agreement with holotype. Six spine articulations similar to those observed on holotype; edge of strongly elevated distal portion of LAP proximally bordering spine articulations slightly undulose. Ventral edge of LAP nearly straight. Ridge on inner side of LAP similar to that of holotype but with slightly bent main part; very shallow, poorly defined vertical furrow dorsally bordering tentacle notch, with single, small perforation at dorsal end of furrow. GZG.INV.78607 is a dissociated distal LAP; nearly 1.5 times wider than high; ventro-proximal tip of LAP fragmentary. Five spine articulations similar to those of holotype; edge of strongly elevated distal portion of LAP proximally bordering spine articulations slightly undulose; row of spine articulations less strongly protruding dorsalwards than in holotype. Ridge on inner side of LAP similar to that of holotype but with smaller, less well-defined ventralward projecting extension of dorsal tip. Irregular perforations loosely arranged in vertical row dorsally bordering tentacle notch. Remarks The structure and position of the spine articulations, the shape of the ridge and the absence of spurs on the outer proximal and inner distal edges strongly suggest that these LAPs are assignable to Ophiacantha. The conspicuously dorsally protruding row of spine articulations clearly differentiates this LAP type from other types assigned to that genus. While, at first sight, this character might seem unusual for Ophiacantha, it is not uncommon among Recent species of the genus such as O. duplex Koehler, 1897 and O. serrata Lyman, 1878, which otherwise perfectly match the LAP morphology of Ophiacantha in its proper sense. Occurrence Late Campanian of Germany., Published as part of Thuy, Ben, 2013, Temporary expansion to shelf depths rather than an onshore-offshore trend: the shallow-water rise and demise of the modern deep-sea brittle star family Ophiacanthidae (Echinodermata: Ophiuroidea), pp. 1-242 in European Journal of Taxonomy 48 on pages 105-106, DOI: 10.5852/ejt.2013.48, http://zenodo.org/record/3822836

Ophiojagtus sp. indet. Fig. 38: 8 Material examined GZG.INV.78818 (1 dissociated LAP) from the early Cenomanian, Late Cretaceous of Waco, Texas, USA. Description GZG.INV.78818 is a dissociated, moderately large, proximal LAP; ventral portion and dorso-proximal edge missing; distal edge convex; proximal edge with very large, conspicuous, well-developed protrusion; outer surface with finely meshed stereom. Five large, ear-shaped spine articulations freestanding on strongly bulging distal portion of LAP and composed of a thick, continuous volute; dorsalward increase in the size of the spine articulations and of the gaps separating them; gap between the spine articulations and the distal edge of the LAP narrow. Inner side of the LAP with moderately well-defined, weakly prominent, broad ridge with conspicuous, strongly widened dorsal tip extending ventro-proximalwards on inner side of protrusion of proximal LAP edge; presence of a ventral part of the ridge not determinable. Single small perforation at the ventral tip of a shallow, poorly defined vertical furrow distally bordering the ventralmost preserved part of the ridge. Remarks Although the single LAP described above is unambiguously assignable to Ophiojagtus gen. nov., its fragmentary nature precludes any species-level identification. The presence of five spine articulations places this LAP closest to O. acklesi sp. nov. or to the LAPs described by Štorc & Žítt (2008) and probably erroneously assigned to O. alternatus comb. nov. (see below). However, since the ventral portion is missing, the shape of the ridge on the inner side cannot be assessed, which precludes any further conclusions on the placement of the specimen at the species level., Published as part of Thuy, Ben, 2013, Temporary expansion to shelf depths rather than an onshore-offshore trend: the shallow-water rise and demise of the modern deep-sea brittle star family Ophiacanthidae (Echinodermata: Ophiuroidea), pp. 1-242 in European Journal of Taxonomy 48 on pages 220-221, DOI: 10.5852/ejt.2013.48, http://zenodo.org/record/3822836, {"references":["Storc R. & Zitt J. 2008. Late Turonian ophiuroids (Echinodermata) from the Bohemian Cretaceous Basin, Czech Republic. Bulletin of Geosciences 83 (2): 123 - 140. http: // dx. doi. org / 10.3140 / bull. geosci. 2008.02.123"]}

Ophiacantha fraterna, based on proximal, median and distal LAPs of seven specimens of different growth stages (disk diameters ranging from 2.46 mm to 7.6 mm) (Fig. 5): Overall shape of LAPs: LAPs in smaller and thus assumedly younger specimens smaller than in larger ones; height:width ratio in proximal LAPs varies from 1 in smallest specimen to 1.4 in largest one; distal LAPs clearly elongate and proximal LAPs of rounded aspect in all examined growth stages; constriction slightly better developed in smaller specimens, in particular in distal LAPs. Ornamentation: vertical striation developed in all LAPs of all examined growth stages; remarkably similar in development and areal extent, except in distal LAPs of the smallest specimen. Diffuse oblique area of dense stereom on the ventral portion of the outer surface clearly developed in all LAPs of smallest specimen; progressively fading in larger specimens. Spurs on outer proximal edge and corresponding area of dense stereom on inner distal edge in proximal LAPs developed in all studied growth stages. Spine articulations: shape, position, arrangement and size pattern of spine articulations constant in all examined growth stages; absolute size of spine articulations increasing according to growth stage; number of spine articulations increasing from five to six in proximal LAPs and from four to five in distal ones from the smallest to the largest examined growth stages. Inner side of LAPs: development of perforations, ridges and knobs on inner side of proximal LAPs remarkably constant in all examined growth stages; distal LAPs in smaller specimens with undifferentiated horizontal ridge on inner side. Tentacle notch constantly developed in all LAPs independent of growth stage., Published as part of Thuy, Ben & St��h, Sabine, 2011, Lateral arm plate morphology in brittle stars (Echinodermata: Ophiuroidea): new perspectives for ophiuroid micropalaeontology and classification, pp. 1-47 in Zootaxa 3013 on page 12, DOI: 10.5281/zenodo.278589