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Reduction in body size of organisms following mass extinctions is well‐known and often ascribed to the Lilliput effect. This phenomenon is expressed as a temporary body size reduction within surviving species. Despite its wide usage the term is often loosely applied to any small post‐extinction taxa. Here we assess the size of bivalves of the family Limidae (Rafineque) prior to, and in the aftermath of, the end‐Triassic mass extinction event. Of the species studied only one occurs prior to the extinction event, though is too scarce to test for the Lilliput effect. Instead, newly evolved species originate at small body sizes and undergo a within‐species size increase, most dramatically demonstrated by Plagiostoma giganteum (Sowerby) which, over two million years, increases in size by 179%. This trend is seen in both field and museum collections. We term this within‐species size increase of newly originated species in the aftermath of mass extinction, the Brobdingnag effect, after the giants that were contemporary with the Lilliputians in Swift's Gulliver's Travels. The size increase results from greater longevity and faster growth rates. The cause of the effect is unclear, although it probably relates to improved environmental conditions. Oxygen‐poor conditions in the Early Jurassic are associated with populations of smaller body size caused by elevated juvenile mortality but these are local/regional effects that do not alter the long‐term, size increase. Although temperature‐size relationships exist for many organisms (Temperature‐Size Rule and Bergmann's Rule), the importance of this is unclear here because of a poorly known Early Jurassic temperature record.

Two new bivalve genera and three new species of the family Limidae from the Upper Eocene of Ukraine are described.

Genus Limatula S. V. Wood, 1839 TYPE SPECIES. — Pecten subauriculatus Montagu, 1808, by subsequent designation.

Limatula gwyni (Sykes, 1903) (Fig. 26 F) MATERIAL EXAMINED. ��� 6 v., DW130. REMARK Originally described from British waters, new record for the Canaries., Published as part of Ortega, Jos�� Rafael & Gofas, Serge, 2019, The unknown bathyal of the Canaries: new species and new records of deep-sea Mollusca, pp. 513-551 in Zoosystema 41 (26) on page 546, DOI: 10.5252/zoosystema2019v41a26, http://zenodo.org/record/3726028

Lima marioni P. Fischer, 1882 (Fig. 26 E) MATERIAL EXAMINED. — 7 v., DW130. REMARK An amphiatlantic species, reported from Brazil and the Azores (Mikkelsen & Bieler 2005), and from the Bay of Biscay to the Ibero-Moroccan Gulf. Consistently associated with white corals. New record for the Canaries.

Limatula laminifera (E. A. Smith, 1885) (Fig. 26 G) MATERIAL EXAMINED. ��� 2 v., DW130. REMARK Originally described from the Caribbean in 390-450 fathoms (713-823 m) and known to us from the seamounts of the central North Atlantic. New record for the Canaries., Published as part of Ortega, Jos�� Rafael & Gofas, Serge, 2019, The unknown bathyal of the Canaries: new species and new records of deep-sea Mollusca, pp. 513-551 in Zoosystema 41 (26) on page 546, DOI: 10.5252/zoosystema2019v41a26, http://zenodo.org/record/3726028, {"references":["SMITH E. A. 1885. - Report on the Lamellibranchiata collected by HMS Challenger during the years 1873 - 1876. Reports of the scientific results of the voyage of HMS \" Challenger \", Zoology 13 (part 35): 1 - 341, pl. 1 - 25. https: // www. biodiversitylibrary. org / item / 16315"]}

Lima marioni P. Fischer, 1882 (Fig. 26 E) MATERIAL EXAMINED. ��� 7 v., DW130. REMARK An amphiatlantic species, reported from Brazil and the Azores (Mikkelsen & Bieler 2005), and from the Bay of Biscay to the Ibero-Moroccan Gulf. Consistently associated with white corals. New record for the Canaries., Published as part of Ortega, Jos�� Rafael & Gofas, Serge, 2019, The unknown bathyal of the Canaries: new species and new records of deep-sea Mollusca, pp. 513-551 in Zoosystema 41 (26) on page 546, DOI: 10.5252/zoosystema2019v41a26, http://zenodo.org/record/3726028

Genus Limatula S. V. Wood, 1839 TYPE SPECIES. ��� Pecten subauriculatus Montagu, 1808, by subsequent designation., Published as part of Ortega, Jos�� Rafael & Gofas, Serge, 2019, The unknown bathyal of the Canaries: new species and new records of deep-sea Mollusca, pp. 513-551 in Zoosystema 41 (26) on page 546, DOI: 10.5252/zoosystema2019v41a26, http://zenodo.org/record/3726028

Genus Lima Brugui��re, 1797 TYPE SPECIES. ��� Lima alba Cuvier, 1797, by subsequent monotypy., Published as part of Ortega, Jos�� Rafael & Gofas, Serge, 2019, The unknown bathyal of the Canaries: new species and new records of deep-sea Mollusca, pp. 513-551 in Zoosystema 41 (26) on page 545, DOI: 10.5252/zoosystema2019v41a26, http://zenodo.org/record/3726028

Limatula laminifera (E. A. Smith, 1885) (Fig. 26 G) MATERIAL EXAMINED. — 2 v., DW130. REMARK Originally described from the Caribbean in 390-450 fathoms (713-823 m) and known to us from the seamounts of the central North Atlantic. New record for the Canaries.

Limatula gwyni (Sykes, 1903) (Fig. 26 F) MATERIAL EXAMINED. — 6 v., DW130. REMARK Originally described from British waters, new record for the Canaries.

Ortega, José Rafael, Gofas, Serge (2019): The unknown bathyal of the Canaries: new species and new records of deep-sea Mollusca. Zoosystema 41 (26): 513-551, DOI: 10.5252/zoosystema2019v41a26

One of the most well-known species in the bivalve family Limidae (d’Orbigny, 1846) is the brightly coloredCtenoides scaber(Born, 1778), commonly known as the rough file clam or flame scallop. Distinguishing this bivalve from its close relative,C. mitis(Lamarck, 1807), can be difficult using only morphological features and has led to much taxonomic confusion throughout the literature. In this study, morphological characters were compared to a molecular phylogeny constructed using three genes (COI, 28S, and H3) in order to differentiateC. scaberandC. mitis.The phylogeny recovered two well-supported clades that differ significantly in shell rib numbers, but not tentacle colors. The two species were then placed in a larger phylogenetic context of the Limidae family, which revealed the need for further systematic revision across genera. As these bivalves are popular in aquaria, cannot be tank-raised, and have been overcollected in the past, proper species identification is important for assessing sustainable collection practices.

We have compiled a complete list of new marine molluscan taxa introduced by Tommaso Allery Di Maria, Marquis of Monterosato (1841–1927). The dates of publication of every single work have been checked against available evidence, and an updated bibliography is also presented. Finally, the type material of all marine taxa expected to be in the collection Monterosato (presently preserved in the Museo Civico di Zoologia in Rome) has been searched in the main collection, and all retrieved specimens have been catalogued. A large majority of the material has been found, representative specimens of each taxon have been illustrated, and remarks on nomenclature and taxonomy have been provided yielding 42 new synonymies, 46 nominal taxa rediscovered, and 6 new combinations.

Family LIMIDAE subovata, Lima [Limatula subovata (Monterosato, 1875 ex Jeffreys ms.)] (Figures 35I, J) 1875b: 9 [XIII: 235]—available name Type material. MCZR–M–13127 — 5 v “Palermo 200—300 m ” “ Lima subovata, Jeffr. Varie località, anche Atlantica” Type locality. Described from Palermo (Sicily) and Azores (Atlantic). Remarks. There is a further lot (MCZR, unnumbered box) of 1 valve identified as L. subovata by Jeffreys, from Palermo, labelled by Brugnone (“ Lima subovata Jeffr. from Jeffr.”), and by Jeffreys (“1443 fms. P.”). Monterosato bought Brugnone’s collection after his death (1884), therefore there is no proof that this shell was part of the type material (but Monterosato has likely studied Brugnone’s collection before acquiring it). However, the morphology of the single valve fits very well the shell features of the type material, showing that both Monterosato and Jeffreys shared the same view on the species identity (Lima subovata Jeffreys, 1876, is separately available and has its own types in USNM). Recorded by MolluscaBase (2018) as Limatula subovata (Monterosato, 1875)., Published as part of Appolloni, Massimo, Smriglio, Carlo, Amati, Bruno, Lugliè, Lorenzo, Nofroni, Italo, Tringali, Lionello P., Mariottini, Paolo & Oliverio, Marco, 2018, Catalogue of the primary types of marine molluscan taxa described by Tommaso Allery Di Maria, Marquis of Monterosato, deposited in the Museo Civico di Zoologia, Roma, pp. 1-138 in Zootaxa 4477 (1) on page 79, DOI: 10.11646/zootaxa.4477.1.1, http://zenodo.org/record/1454652

In order to enhance the understanding of Pacific Colombia’s deep-water marine fauna, a benthic research cruise (2012 TUM Offshore 6 and 7) was conducted off the coast of the Department of Nariño, in southern Colombia. Biological, oceanographic and sediment samples from the continental shelf and slope were collected at depths between 350 and 941 m. A new species of Malletia obtained on that cruise is described and compared with other species from the eastern Pacific. Sixteen species of bivalve mollusks (belonging to 12 families and 15 genera) were identified. Five of them were the first records for Pacific Colombia (Jupiterialobula, Limatulasaturna, Lucinomaheroica, Cuspidariapanamensis, and Dallicordiaalaskana). Four of them had geographic distributions that now extend to Tumaco at the southern end of Nariño.

Mantellina translucens n. sp. inhabits the deep reefs (215-310 m) off southeastern Curacao, occurring singly or in pairs, attached to vertical rock walls and boulders by thin byssal threads. This species differs from all living Limidae in having an exceptionally thin, comarginally corrugated shell that is longer than tall and lacks radial sculpture. This new species possesses a unique suite of characters associated with adaptations to an epibyssate mode of life in bathyal habitats, including simplification of the digest- ive tract, possibly indicating omnivory. It is assigned to the genus Mantellina Sacco, 1904, previously known only from fossil deposits of Burdigalian to Serravallian Miocene age of the Central Paratethys, on the basis of similar shell morphology. Anatomical characters and ribosomal DNA sequence data (18S and 16S genes) confirm placement of this taxon within the family Limidae, yet its shell superficial- ly resembles those of several genera of the extinct family Inoceramidae, while differing in hinge morph- ology and shell ultrastructure. A preliminary molecular phylogeny recovered Limidae as a monophyletic clade within Pteriomorphia, with Mantellina derived relative to Limaria, and sister group to a clade containing the remaining representatives of Limidae. Ctenoides was not monophyletic. The phylogenetic tree based on molecular data does not support previously proposed suprageneric relation- ships based on morphological data.

The structure of the spermatozoon of Acesta oophaga (Bivalvia) is described by transmission electron microscopy. This cold-seep species produces ect-aquasperm, confirming that it is a broadcast spawner. The head of the sperm consists of a small, rounded, electron-dense nucleus, capped by a short conical acrosome, the contents of which are differentiated. The mid-piece contains a pair of orthogonally arranged centrioles surrounded by five spherical mitochondria. The gonad of one individual contained eggs and sperm, which supports the hypothesis that A. oophaga is a sequential hermaphrodite.

The recent Compendium of bivalves by Huber [(2010) Compendium of bivalves. ConchBooks, Hackenheim] introduces a large number of taxonomic and nomenclatural changes across the Bivalvia, worldwide. In this paper, we discuss a number of these changes that pertain to the New Zealand fauna. Although many of Huber's changes are justified, we find that there are a significant number with which we disagree, noting that many of them have been made in poorly understood groups with what seems to us rather weak evidence for the change. We have been guided by the belief that, in such cases, one should opt for taxonomic stability and await stronger data. We also argue that in a number of these difficult groups such data are likely to be molecular. We note also that in reviewing some of these cases, it has been convenient to make a small number of original changes. Recent records of Lima mestayerae Marwick, 1924 are based on mislocalised specimens of Lima nimbifer Iredale, 1924 from eastern Australia. Specimens from the...

Limaria loscombi (Sowerby, G.B. I, 1823) Fig. 6 h���j Lima loscombi Sowerby G.B. I, 1823 (part 17-unnumbered page, pl. 113, fig. 4). Lima loscombii G.B. Sowerby���Jeffreys 1879 (p. 564). Lima loscombii Sowerby���Hidalgo 1917 (p. 386). Lima loscombi Sowerby���Tebble 1966 (p. 66, pl. 11, figs. c, m). Limea (Limatulella) loscombei [sic] (Sowerby, 1820)��� Nordsieck 1969 (p. 59, pl. 10, fig. 36.30). Limea loscombii (Sowerby, 1823) ��� Barash & Danin 1992 (p. 257). Limaria loscombii (Sowerby, 1820) ��� Poppe & Goto 1993 (p. 76, pl. 12, fig. 11). Limea loscombi (G.B. Sowerby I, 1823) ��� Giannuzzi-Savelli et al. 2001 (p. 222, figs. 472���473). Limea loscombii (Sowerby G.B. I, 1823) ��� Repetto et al. 2005 (p. 305, top left fig.). Limaria loscombi (G B Sowerby I, 1823) ��� Oliver et al. 2016 (online resource). Diagnostic characters. Suboval, oblique shell; rounded anterior side; nearly straight posterior side; large ligamental pit occupying most of the hinge line; weak radial riblets vanishing towards the anterior side and almost absent over the umbonal area. Prodissoconch: shell type ST-2A; P-2 length about 240 ��m; equilateral triangular outline; convex profile; P-1 surface rough; P-1/P-2 boundary ill-defined; P-2 with commarginal threads on the later stages; transition to the nepioconch marked by a narrow, flattened lip. Occurrence. Box-corer sample BC72 (1 specimen). Height: 6 mm. Distribution and habitat. Limaria loscombi ranges from Norway and Iceland to West Africa, the Azores, Cape Verde and into the Mediterranean, dwelling on various soft substrates from infralittoral to bathyal depths, often associated with sponges (Nordsieck 1969; Barash & Danin 1992; Poppe & Goto 1993; Oliver et al. 2016). P��r��s & Picard (1964) regarded the species as an exclusive characteristic element of DC (coastal detritic bottom) biocoenosis. Fossil record. Pliocene of Sicily (Monterosato 1872)., Published as part of Negri, Mauro Pietro & Corselli, Cesare, 2016, Bathyal Mollusca from the cold-water coral biotope of Santa Maria di Leuca (Apulian margin, southern Italy), pp. 1-97 in Zootaxa 4186 (1) on pages 31-32, DOI: 10.11646/zootaxa.4186.1.1, http://zenodo.org/record/165288, {"references":["Nordsieck, F. (1969) Die europaischen Meeresmuscheln (Bivalvia) vom Eismeer bis Kapverden, Mittelmeer und Schwarzes Meer. Gustav Fischer Verlag, Stuttgart, XIII + 256 pp.","Barash, A. & Danin, Z. (1992) Annotated list of mediterranean molluscs of Israel and Sinai. In: Fauna Palaestina, Mollusca I. Keterpress Enterprises, Jerusalem, pp. 1 - 405.","Poppe, G. T. & Goto, Y. (1993) European Seashells. Volume II. (Scaphopoda, Bivalvia, Cephalopoda). Verlag Christa Hemmen, Wiesbaden, 221 pp.","Giannuzzi-Savelli, R., Pusateri, F., Palmeri, A., Ebreo, C. †, Coppini, M., Margelli, A., Bogi, C. (2001) Atlante delle conchiglie marine del Mediterraneo. Vol. 7 (Bivalvia: Protobranchia-Pteriomorphia). Evolver, Roma, 246 pp.","Repetto, G., Orlando, F. & Arduino, G. (2005) Conchiglie del Mediterraneo: 1770 specie illustrate con distribuzione e frequenza. Amici del Museo \" Federico Eusebio \", Alba, 392 pp.","Oliver, P. G., Holmes, A. M., Killeen, I. J. & Turner, J. A. (2016) Marine Bivalve Shells of the British Isles (Mollusca: Bivalvia). Amgueddfa Cymru-National Museum Wales. Available from: http: // naturalhistory. museumwales. ac. uk / britishbivalves. (Accessed 25 August 2016)","Peres, J. - M. & Picard, J. (1964) Nouveau manuel de bionomie bentique de la Mer Mediterranee. Recueil des Travaux de la Station Marine d'Endoume, 31, 1 - 137.","Monterosato, T. A. di (1872) Notizie intorno alle conchiglie fossili di Monte Pellegrino e Ficarazzi. Ufficio Tipografico Michele Amenta, Palermo, 44 pp. http: // dx. doi. org / 10.5962 / bhl. title. 50743"]}

Limea crassa (Forbes, 1844) Fig. 6 n���p Lima (Limatula) crassa Forbes, 1844 (p. 193). Limea sarsii Lov��n, 1846 (p. 186). Notolimea crassa crassa (Forbes, 1843) ��� Nordsieck 1969 (p. 56). Notolimea crassa sarsi (Loven, 1846) ��� Nordsieck 1969 (p. 56, pl. 9, fig. 36.01). Lima (Notolimea) crassa (Forbes) ��� Di Geronimo & Panetta 1973 (p. 101, pl. 2, fig. 10). Limea (Notolimea) crassa (Forbes) ��� Di Geronimo 1974 (p. 154, pl. 3, fig. 6). Limea crassa (Forbes) ��� Di Geronimo & Bellagamba 1985 (pl. 3, fig. 10). Notolimea crassa (Forbes, 1844) ��� Cossignani et al. 1992 (fig. 300); Poppe & Goto 1993 (p. 77, pl. 12, fig. 13); Salas 1996 (p. 58); Giannuzzi-Savelli et al. 2001 (p. 222, fig. 471); Repetto et al. 2005 (p. 305, mid left fig.); Beck et al. 2006 (p. 103, top fig.). Notolimea crassa (Forbes) ���Rosso et al. 2010 (fig. 11 F). Limea crassa (Forbes, 1844) ��� Oliver et al. 2016 (online resource). Diagnostic characters. Oval, nearly equilateral shell; hinge line with small denticles on both sides of the ligamental pit; commarginal lamellar folds passing over radial ribs; raised, fluted to spatulate projections at the intersections. Prodissoconch: shell type ST-2D; length about 110 ��m; roundish D-shaped outline; convex profile; surface with fine granulations; P-2 absent; transition to the nepioconch marked by narrow metamorphic shell lip. Occurrence. Box-corer samples BC04 (46), BC05 (57), BC11 (3), BC22 (1), BC66 (32), BC67 (6), BC68 (1), BC71 (1), BC72 (187); cores BC04 (33), BC05 (111), BC21 (85), BC51 (67), BC52 (3), BC67 (1), BC72 (89). Maximum height: 3.5 mm. Distribution and habitat. Limea crassa is distributed from Norway and Iceland to West Africa, the Azores, St. Helena and the Mediterranean, dwelling on muddy bottoms from about 30 to 2700 m depth (Nordsieck 1969; Poppe & Goto 1993; Pons-Moy�� & Pons 1999, Oliver et al. 2016). It was regarded as an accompanying element of both VP (bathyal mud) and CB (deep-sea white corals) biocoenoses (Di Geronimo & Bellagamba 1985), also occurring in the Abra-Nucula biocoenosis in the bathyal of Taranto (Di Geronimo & Panetta 1973). In the Santa Maria di Leuca CWC biotope, it was found on the muddy bottoms around the coral colonies (Mastrototaro et al. 2010), being common in mollusk mud thanatofacies (Rosso et al. 2010). Fossil record. Pliocene and Pleistocene of Italy (Di Geronimo & Bellagamba 1985; Barrier et al. 1987; Di Geronimo & La Perna 1997; Monegatti & Raffi 2001; Tabanelli 2008)., Published as part of Negri, Mauro Pietro & Corselli, Cesare, 2016, Bathyal Mollusca from the cold-water coral biotope of Santa Maria di Leuca (Apulian margin, southern Italy), pp. 1-97 in Zootaxa 4186 (1) on pages 32-33, DOI: 10.11646/zootaxa.4186.1.1, http://zenodo.org/record/165288, {"references":["Forbes, E. (1844) Report on the Mollusca and Radiata of the Aegean Sea, and on their distribution, considered as bearing on Geology. Reports of the Thirteenth Meeting of the British Association for the Advancement of Science; held at Cork in August 1843, 130 - 193.","Loven, S. (1846) Nordens Hafs-Mollusker. Index Molluscorum litora Scandinaviae occidentalia habitantium. Ofversigt af Kongl. Vetenskaps-Akademiens Forhandlingar, 3 (5), 134 - 160, 3 (6), 182 - 204.","Forbes, E. (1843) On the species of Neaera (Gray) inhabiting the Egean Sea. Proceedings of the Zoological Society of London, 11, 1 - 75.","Nordsieck, F. (1969) Die europaischen Meeresmuscheln (Bivalvia) vom Eismeer bis Kapverden, Mittelmeer und Schwarzes Meer. Gustav Fischer Verlag, Stuttgart, XIII + 256 pp.","Di Geronimo, I. & Panetta, P. (1973) La Malacofauna Batiale del Golfo di Taranto. Conchiglie, 9 (5 - 6), 69 - 121.","Di Geronimo, I. (1974) Molluschi bentonici in sedimenti recenti batiali e abissali dello Jonio. Conchiglie, 10 (7 - 8), 133 - 172.","Di Geronimo, I. & Bellagamba, M. (1985) Malacofaune dei dragaggi BS 77 - 1 e BS 77 - 2 (Sardegna nord orientale). Bollettino della Societa Paleontologica Italiana, 24 (2 - 3), 111 - 129.","Cossignani, T., Cossignani, V., Di Nisio, A. & Passamonti, M. (1992) Atlante delle conchiglie del medio Adriatico. L'Informatore Piceno Editore, Ancona, 120 pp.","Poppe, G. T. & Goto, Y. (1993) European Seashells. Volume II. (Scaphopoda, Bivalvia, Cephalopoda). Verlag Christa Hemmen, Wiesbaden, 221 pp.","Salas, C. (1996) Marine Bivalves from off the southern Iberian Peninsula collected by the Balgim and Fauna 1 expeditions. Haliotis, 25, 33 - 100.","Giannuzzi-Savelli, R., Pusateri, F., Palmeri, A., Ebreo, C. †, Coppini, M., Margelli, A., Bogi, C. (2001) Atlante delle conchiglie marine del Mediterraneo. Vol. 7 (Bivalvia: Protobranchia-Pteriomorphia). Evolver, Roma, 246 pp.","Repetto, G., Orlando, F. & Arduino, G. (2005) Conchiglie del Mediterraneo: 1770 specie illustrate con distribuzione e frequenza. Amici del Museo \" Federico Eusebio \", Alba, 392 pp.","Beck, T., Metzger, T. & Freiwald, A. (2006) BIAS-Biodiversity inventorial atlas of macrobenthic seamount animals. OASIS Deliverable 25, Final Report, 124 pp.","Oliver, P. G., Holmes, A. M., Killeen, I. J. & Turner, J. A. (2016) Marine Bivalve Shells of the British Isles (Mollusca: Bivalvia). Amgueddfa Cymru-National Museum Wales. Available from: http: // naturalhistory. museumwales. ac. uk / britishbivalves. (Accessed 25 August 2016)","Pons-Moya, J. & Pons, G. X. (1999) Noves dades sobre molluscs de profunditat del SW de Mallorca (Illes Balears, Mediterrania Occidental). Bolletin de la Societat d'Historia Natural de les Balears, 42, 39 - 46.","Barrier, P., Casale, V., Costa, B., Di Geronimo, I., Olivieri, O. & Rosso, A. (1987) La sezione Plio-Pleistocenica di Pavigliana (Reggio Calabria). Bollettino della Societa Paleontologica Italiana, 25 (2), 107 - 144.","Monegatti, P. & Raffi, S. (2001) Taxonomic diversity and stratigraphic distribution of Mediterranean Pliocene bivalves. Palaeogeography, Palaeoclimatology, Palaeoecology, 165, 171 - 193. http: // dx. doi. org / 10.1016 / s 0031 - 0182 (00) 00159 - 0","Tabanelli, C. (2008) Associazioni di paleocomunita batiali a molluschi bentonici nel Pliocene della Romagna. Quaderno di Studi e Notizie di Storia Naturale della Romagna, 26, 1 - 80."]}

Family Limidae Rafinesque, 1815 Remarks. There are few records of limids in the fossil seep record, with only three named species in three genera (two from Japan, Lima Cuvier, 1798 and Limatula Wood, 1839, and one from Svalbard, Pseudolimea Arkell in Douglas & Arkell, 1932). Lima zushiensis Yokoyama, 1920, was reported by Hirayama (1973) from a tentative seep-related fauna in the middle Miocene Hiranita Formation, and Amano & Kanno (1991) reported Limatula cf. (Limatula) vladivostokensis (Scarlato, 1955) and another indeterminate species of Limatula from the Pliocene Nadachi Formation. Hryniewicz et al. (2014) recently reported Pseudolimea arctica (Zakharov, 1966) from the Berriasian (local Ryazanian) Slottsm��ya Member. No limid bivalve has been reported from modern New Zealand seep environments, although several genera are known from New Zealand waters inhabiting other marine environments in the present day (Spencer et al. 2009)., Published as part of Saether, Kristian P., Jingeng, Sha, Little, Crispin T. S. & Campbell, Kathleen A., 2016, New records and a new species of bivalve (Mollusca: Bivalvia) from Miocene hydrocarbon seep deposits, North Island, New Zealand, pp. 1-26 in Zootaxa 4154 (1) on page 8, DOI: 10.11646/zootaxa.4154.1.1, http://zenodo.org/record/272151, {"references":["Rafinesque, C. S. (1815) Analyse de la nature ou tableau de l'univers et des corps organises. Jean Barravecchia, Palermo, 224 pp. http: // dx. doi. org / 10.5962 / bhl. title. 106607","Wood, S. V. (1839) Descriptions of the species of the genus Lima, from the coralline Crag, in the cabinet of Searles Valentine Wood, Esq., late curator of the Geological Society of London. The Magazine of Natural History, New Series, 3, 233 - 236.","Yokoyama, M. (1920) Fossils from the Miura Peninsula and its immediate north. Journal of the College of Science, Imperial University of Tokyo, 39, 1 - 198.","Hirayama, K. (1973) Molluscan fauna from the Miocene Hiranita Formation, Chichibu Basin, Saitama Prefecture, Japan. Science Reports of the Tokohu University, Series 2 (Geology), Hatai Memorial Volume 6, 163 - 177.","Amano, K. & Kanno, S. (1991) Composition and structure of Pliocene molluscan associations in the western part of Joetsu City, Niigata Prefecture. Fossils, 51, 1 - 14.","Scarlato, O. A. (1955) Class bivalve molluscs - Bivalvia. In: Uschakov, P. V. (Ed.), Atlas of invertebrates from Far East seas of the USSR. Academy of Sciences of the USSR, Moscow, pp. 185 - 198. [in Russian]","Hryniewicz, K., Little, C. T. S. & Nakrem, H. A. (2014) Bivalves from the latest Jurassic - earliest Cretaceous hydrocarbon seep carbonates from central Spitsbergen, Svalbard. Zootaxa, 3859 (1), 1 - 66. http: // dx. doi. org / 10.11646 / zootaxa. 3859.1.1","Zakharov, V. A. (1966) Late Jurassic and Early Cretaceous bivalves of northern Siberia and their paleoecology. Order Anisomyaria. Nauka, Moscow, 189 pp. [in Russian]","Spencer, H. G., Marshall, B. A., Maxwell, P. A., Grant-Mackie, J. A., Stilwell, J. D., Willan, R. C., Campbell, H. J., Crampton, J. S., Henderson, R. A., Bradshaw, M. A., Waterhouse, J. B. & Pojeta, J. Jr. (2009) Phylum Mollusca: Chitons, clams, tusk shells, snails, squids, and kin. In: Gordon, D. P. (Ed.), New Zealand Inventory of Biodiversity. Vol. 1. Kingdom Animalia. Radiata, Lophotrochozoa, Deuterostomia. Canterbury University Press, Canterbury, pp. 161 - 254."]}

Fourteen bivalve taxa belonging to 11 families are present in at least 13 early to middle Miocene hydrocarbon seep deposits in the East Coast Basin, North Island, New Zealand. Among these are at least three new species, one of which, Semeloidea (s. l.) bexhavenensis sp. nov. (Lasaeidae), is described here. New distribution data are recorded for bivalve species in the families Limidae, Propeamussiidae, Malleidae and Solemyidae. Additional morphological details of Gigantidas coseli (Mytilidae) and Pratulum quinarium (Cardiidae) are provided based upon previously unrecorded internal shell features. Palaeoecological analysis indicates that bivalves utilized a broad range of modes of life and niches within the New Zealand Miocene seep environment, and no more than ca. 30% of these bivalve species were likely to have been obligate to seeps.

Acesta cf. saginata Marshall, 2001 (Fig. 5 D) Material. One specimen from Rocky Knob (Y16/f0642), medium sized, L4652, UOA. Description. Shell small for genus (H ��� 70.0 mm, I ��� 20 mm; L ��� 55.0 mm; see remarks below), shell length ca. 80% of shell height, single valve inflation ca. 20% of shell length (see remarks below); dorsal margin straight (running for short distance behind umbo before being eroded), nature of passage to posterior margin unknown; anterodorsal margin running at ca. 45�� from umbo, gently convex, evenly rounded; other margins unknown; external sculpture unknown; finely spaced, subtly wavy, radial striae on shell interior, especially strong in anterior half of medial region, mostly obsolete elsewhere, a few very faint striae visible in posterior half. Remarks. The single specimen is an internal mould of a left valve, with the ventral portion and auricle only partially preserved, leaving any attempt at specific identification tenuous. The fossil seep species is morphologically closest to Acesta saginata Marshall, 2001, based upon the broadness of the beak in comparison with the other modern New Zealand species, Acesta maui Marshall, 2001, and the four New Zealand fossil species (all narrower except Acesta regia, in which it is broader). Also, of the two modern species, A. saginata has the most strongly internally reflected radial striae, which closely resemble the narrowly spaced striae on Acesta cf. saginata. The nature and extent of internal reflections on the other New Zealand fossil species are unknown. Estimations of the size of our specimen from the curvature of the antero- and posterodorsal flanks (either side of the narrow beak) and from the position of a faint muscle scar suggest that it was considerably smaller than the other New Zealand species, fossil and modern. The specimen also appears to be considerably less inflated than A. saginata notwithstanding their similar height vs. length ratios. Nonetheless, owing to a lack of complete specimens, these dimensions can only be regarded as approximate, especially inflation vs. length. The fine radial striae in the medial portion probably reflect a moderate to strong external radial sculpture, and their subtle waviness may indicate where weaker concentric elements cross the radials. All four New Zealand fossil species are older than those from the Rocky Knob deposit, the youngest records being from the Waitakian period (late Oligocene���early Miocene), but the two Recent species suggest that the genus has been present in New Zealand throughout this time., Published as part of Saether, Kristian P., Jingeng, Sha, Little, Crispin T. S. & Campbell, Kathleen A., 2016, New records and a new species of bivalve (Mollusca: Bivalvia) from Miocene hydrocarbon seep deposits, North Island, New Zealand, pp. 1-26 in Zootaxa 4154 (1) on page 9, DOI: 10.11646/zootaxa.4154.1.1, http://zenodo.org/record/272151, {"references":["Marshall, B. A. (2001) The genus Acesta H. & A. Adams, 1858 in the south-west Pacific (Bivalvia: Limidae). In: Bouchet, P. & Marshall, B. A. (Eds.), Tropical deep-sea benthos. Vol. 22. Memoires du Museum National d'Histoire Naturelle, 185, pp. 97 - 109."]}

Limatula subauriculata Montagu, 1808 Fig. 6 k���m Pecten subauriculata [sic] Montagu, 1808 (p. 63, pl. 29, fig. 2). Lima subauriculata Montagu���Jeffreys 1879 (p. 564); Hidalgo 1917 (p. 387). Lima (Limatula) subauriculata (Montagu) ��� Tebble 1966 (p. 68, text-figs. 28a���b); Di Geronimo & Panetta 1973 (p. 101, pl. 3, fig. 9). Limatula subauriculata subauriculata (Montagu, 1808) ��� Nordsieck 1969 (p. 57, pl. 9, figs. 36.10���36.11). Limatula subauriculata (Montagu, 1808) ��� Barash & Danin 1992 (p. 258, fig. 275); Cossignani et al. 1992 (fig. 299); Poppe & Goto 1993 (p. 77, pl. 12, fig. 8); Giannuzzi-Savelli et al. 2001 (p. 222, fig. 466); Repetto et al. 2005 (p. 304, bottom left fig); Beck et al. 2006 (p. 102, mid fig); Oliver et al. 2016 (online resource). Diagnostic characters. High, oval, and almost equilateral shell; fan-shaped ligamental pit; even radial riblets; distinct median radial furrow on the right valve; strong median rib on the left valve. Prodissoconch: shell type ST- 2D; length about 120 ��m; roundish D-shaped outline; convex profile; surface almost smooth; P-2 replaced by narrow shell lip; transition to the nepioconch well marked. Occurrence. Box-corer samples BC05 (6 specimens), BC11 (1), BC66 (6), BC67 (4), BC71 (6), BC72 (71); cores BC04 (2), BC05 (6), BC21 (14), BC51 (6), BC67 (5), BC72 (20). Maximum height: 6 mm. Distribution and habitat. Limatula subauriculata is distributed from Greenland to the Gulf of Mexico, the Canaries and the Mediterranean; it thrives on muddy sand to sandy gravel bottoms in a wide bathymetric range, from shallow infralittoral to about 3200 m depth (Tebble 1966; Nordsieck 1969; Barash & Danin 1992; Poppe & Goto 1993; Pons-Moy�� & Pons 1999; Oliver et al. 2016). Mastrototaro et al. (2010) recorded the species already in the Santa Maria di Leuca CWC biotope. Fossil record. Miocene to Recent (Monegatti & Raffi 2001); Pliocene of Italy (Monterosato 1872; Tabanelli 2008); Pleistocene of Calabria (Barrier et al. 1987) and Sardinia (Di Geronimo & Bellagamba 1985)., Published as part of Negri, Mauro Pietro & Corselli, Cesare, 2016, Bathyal Mollusca from the cold-water coral biotope of Santa Maria di Leuca (Apulian margin, southern Italy), pp. 1-97 in Zootaxa 4186 (1) on page 32, DOI: 10.11646/zootaxa.4186.1.1, http://zenodo.org/record/165288, {"references":["Montagu, G. (1808) Supplement to Testacea Britannica with additional plates. Woolmer, Exeter, V + 183 pp.","Hidalgo, J. G. (1917) Fauna Malacologica de Espana, Portugal y las Baleares. Trabajos del Museo Nacional de Ciencias Naturales, Zoologia, 30, 1 - 752.","Tebble, N. (1966) British bivalve seashells. Her Majesty's Stationery Office, Edinburgh, 213 pp.","Di Geronimo, I. & Panetta, P. (1973) La Malacofauna Batiale del Golfo di Taranto. Conchiglie, 9 (5 - 6), 69 - 121.","Nordsieck, F. (1969) Die europaischen Meeresmuscheln (Bivalvia) vom Eismeer bis Kapverden, Mittelmeer und Schwarzes Meer. Gustav Fischer Verlag, Stuttgart, XIII + 256 pp.","Barash, A. & Danin, Z. (1992) Annotated list of mediterranean molluscs of Israel and Sinai. In: Fauna Palaestina, Mollusca I. Keterpress Enterprises, Jerusalem, pp. 1 - 405.","Cossignani, T., Cossignani, V., Di Nisio, A. & Passamonti, M. (1992) Atlante delle conchiglie del medio Adriatico. L'Informatore Piceno Editore, Ancona, 120 pp.","Poppe, G. T. & Goto, Y. (1993) European Seashells. Volume II. (Scaphopoda, Bivalvia, Cephalopoda). Verlag Christa Hemmen, Wiesbaden, 221 pp.","Giannuzzi-Savelli, R., Pusateri, F., Palmeri, A., Ebreo, C. †, Coppini, M., Margelli, A., Bogi, C. (2001) Atlante delle conchiglie marine del Mediterraneo. Vol. 7 (Bivalvia: Protobranchia-Pteriomorphia). Evolver, Roma, 246 pp.","Repetto, G., Orlando, F. & Arduino, G. (2005) Conchiglie del Mediterraneo: 1770 specie illustrate con distribuzione e frequenza. Amici del Museo \" Federico Eusebio \", Alba, 392 pp.","Beck, T., Metzger, T. & Freiwald, A. (2006) BIAS-Biodiversity inventorial atlas of macrobenthic seamount animals. OASIS Deliverable 25, Final Report, 124 pp.","Oliver, P. G., Holmes, A. M., Killeen, I. J. & Turner, J. A. (2016) Marine Bivalve Shells of the British Isles (Mollusca: Bivalvia). Amgueddfa Cymru-National Museum Wales. Available from: http: // naturalhistory. museumwales. ac. uk / britishbivalves. (Accessed 25 August 2016)","Pons-Moya, J. & Pons, G. X. (1999) Noves dades sobre molluscs de profunditat del SW de Mallorca (Illes Balears, Mediterrania Occidental). Bolletin de la Societat d'Historia Natural de les Balears, 42, 39 - 46.","Monegatti, P. & Raffi, S. (2001) Taxonomic diversity and stratigraphic distribution of Mediterranean Pliocene bivalves. Palaeogeography, Palaeoclimatology, Palaeoecology, 165, 171 - 193. http: // dx. doi. org / 10.1016 / s 0031 - 0182 (00) 00159 - 0","Monterosato, T. A. di (1872) Notizie intorno alle conchiglie fossili di Monte Pellegrino e Ficarazzi. Ufficio Tipografico Michele Amenta, Palermo, 44 pp. http: // dx. doi. org / 10.5962 / bhl. title. 50743","Tabanelli, C. (2008) Associazioni di paleocomunita batiali a molluschi bentonici nel Pliocene della Romagna. Quaderno di Studi e Notizie di Storia Naturale della Romagna, 26, 1 - 80.","Barrier, P., Casale, V., Costa, B., Di Geronimo, I., Olivieri, O. & Rosso, A. (1987) La sezione Plio-Pleistocenica di Pavigliana (Reggio Calabria). Bollettino della Societa Paleontologica Italiana, 25 (2), 107 - 144.","Di Geronimo, I. & Bellagamba, M. (1985) Malacofaune dei dragaggi BS 77 - 1 e BS 77 - 2 (Sardegna nord orientale). Bollettino della Societa Paleontologica Italiana, 24 (2 - 3), 111 - 129."]}

Based on newly collected material from the uppermost Smithian and lower to middle Spathian (Oleneki- an, Lower Triassic) of the Salt Range and Surghar Range (Pakistan), 15 bivalve species belonging to 11 genera are described, including two new genera, Eobuchia and Dimor- phoconcha , and one new species, Palaeoneilo ? fortistriata . Eo- buchia gen. nov. is placed in a new subfamily, the Eobuchiinae, which differs from the Buchiinae in having an almost planar and only moderately inclined or offset right anterior auricle. Inclination of the right anterior auricle is proposed as a synapomorphy of the revised suborder Monotidina, which includes the Buchiidae, Monotidae, Oxytomidae and, tentatively, the Dolponellidae. The Pseudo- monotidae, Chaenocardiidae and Claraiidae are discussed as candidate ancestors of the Monotidina. Dimorphoconcha gen. nov., provisionally placed in the Limidae, is a morphologically unusual genus characterized by a globose shell centre and a strongly plicate fringe. Permophorus costatus , which was pre- viously known exclusively from Permian strata, is reported from the Spathian of the Surghar Range. This record extends the range of P. costatus for at least 8 Myr and makes it the first reported Lazarus species , with an outage of more than 2 Myr after the end-Permian mass extinction. Ten of 15 species recognized in this study have not been reported from other regions, which may indicate increasing provincialism towards the end of the Early Triassic, or, alternatively, reflect the still insufficient knowledge of ben- thic faunas from the epoch that followed the greatest crisis in the history of life.

Limatula chilensis sp. nov. is described on the basis of shell morphology and soft tissue anatomy. Studied individuals were obtained periodically between June 2008 and January 2009 from sublittoral soft-sediments off Punta Coloso in northern Chile at depths of 22 to 33 m. Shell morphology of the new species differs from the 4 described species of Limatula from the Pacific coast of South America and Antarctic Peninsula (5°-65°S). Main characteristics of L. chilensis include an average height of 3.50 mm (range 2.36-4.42, SD ± 0.60, n = 34), number of radial ribs 16-21 (mode = 20, SD= 1.69, n = 8) and greater shell obliqueness. L. chilensis is the only known species of the genus found off northern Chile.

Genetic connectivity and habitat characteristics were examined in two species of Acesta clams (Bivalvia: Limidae) from submarine seamounts and continental slopes along the western North America margin. Two species were identified from dive videos obtained with submarine remotely operated vehicles that surveyed a 2200-km range between 27� and 46� N latitude. Acesta sphoni was only found at shallower habitats (545‐860 m depth) in the southern part of this range, whereas Acesta mori was more abundant and widely distributed in deeper habitats (1029‐1996 m). Both species occurred on seamounts and on the walls of submarine canyons and continental slopes. Segregation of these species by depth exposes them to correlated differences in water temperatures and dissolved oxygen concentrations. Ninety-eight individuals sampled from seven seamounts and one escarpment locality were characterized with DNA-barcodes based on 643 base pairs of mitochondrial cytochrome-c-oxidase subunit I (COI). Further analysis of these sequences revealed no significant geographical subdivision across the sampled range. This lack of differentiation suggests ongoing genetic exchange between the seamount populations and those possibly distributed along the continental margins. Examination of regional bathymetric profiles suggested that an abundance of suitable habitat might exist along these margins.

A novel bacterium was discovered in the gills of the large bivalve Acesta excavata (Limidae) from coral reefs on the northeast Atlantic margin near the shelf break of the fishing ground Haltenbanken of Norway, and confirmed present in A. excavata from a rock-wall in the Trondheimsfjord. Purified gill DNA contained one dominant bacterial rRNA operon as indicated from analysis of broad range bacterial PCR amplicons in denaturant gradient gels, in clone libraries and by direct sequencing. The sequences originated from an unknown member of the order Oceanospirillales and its 16S rRNA gene fell within a clade of strictly marine invertebrate-associated Gammaproteobacteria. Visual inspection by fluorescent in situ hybridization and transmission electron microscopy indicated a pleomorphic bacterium with no visible cell wall, located in aggregates inside vacuoles scattered within the gill cells cytoplasm. Intracellular Oceanospirillales exist in bathymodiolin mussels (parasites), Osedax worms and whiteflies (symbionts). This bacterium apparently lives in a specific association with the Acesta.

Bivalve molluscs are known for shadow responses involving closure or retraction of the siphon and valve adduction. In representative genera [Spisula solidissima (Dillwyn, 1918), Mercenaria mercenaria (Linnaeus, 1758), Lima scabra (Born, 1778)], the pallial nerves contain photosensitive fibers that exhibit physiological shadow responses. These photoreceptors are inhibited by light but trigger an excitatory burst of spikes to a shadow, the off-response. Equivalent responses are seen in bivalve eyes, e.g., in optic fibers from the siphon tentacle eyes of Cardium edule (Linnaeus, 1758) and the mantle eyes of scallops (Pectinidae) and file clams (Limidae). In scallops, they form a distal retinal layer of ciliary receptors, distinct from a proximal microvillar layer that is excited by light. In off-receptors (ciliary), light inhibition is the result of a hyperpolarizing receptor potential with spikes generated on the rebound depolarization at dimming. In contrast, the proximal on-receptors are excited...

Five species of the genus Limatula and one of Limea were found in a total of 83 samples taken from deep waters (700– 1950 m) off Brazil. Limatula laminifera (Smith, 1885) and Limea lirata Allen, 2004 were not previously reported from Brazil. Limatula confusa (Smith, 1885) and L. louiseae Clarke, 1974, although already reported for Brazilian waters, have their distribution extended southward. Limatula domaneschii n.sp. is described from the Campos Basin (˜22° S). It is diagnosed by concentric lamellae strengthening towards the ventral margin of the shell, and absence of axial ornamentation; an internal median groove is not present. A fifth Limatula species is present, and we strongly suspect that it is also new to science, but a formal description is delayed until additional specimens are collected.

This paper describes 97 molluskan species (45 Bivalvia, 3 Scaphopoda, 49 Gastropoda) recovered from bathyal bottoms off Santa Maria di Leuca (Puglia, Italy), in the northern Ionian Sea, and provides data about their taxonomy, geographical distribution, habitat, ecological requirements and fossil record. Only 6 species remain unidentified, and all are illustrated. The bivalve-dominated assemblages belong to the so-called "cold-water coral ecosystem". They appear to depend mainly on substrate characteristics, with faunas related to hard substrate around coral-colonized mound tops, and mud-related ones in inter-mound areas, respectively. Nuculanoida and Pectinoidea among bivalves, and Conoidea and Pyramidelloidea among gastropods are the most diverse suprafamilial groups. The present paper is the first comprehensive taxonomic overview of Mediterranean bathyal mollusks including larval shell characters.

Gagnon, Jean-Marc, Kenchington, Ellen, Port, Antony, Anstey, Lynne J., Murillo, Francisco Javier (2015): Morphological and genetic variation in North Atlantic giant file clams, Acesta spp. (Bivalvia: Limidae), with description of a new cryptic species in the northwest Atlantic. Zootaxa 4007 (2): 151-180, DOI: http://dx.doi.org/10.11646/zootaxa.4007.2.1

Acesta cryptadelphe sp. nov. Figs. 2, 3 C���D, 6, 14��� 16 Material examined. Collection data for each sample set is shown in Table 2. The holotype and three paratypes are from The Gully, off Nova Scotia; nine paratypes are from Beothuk Knoll, off northeast Newfoundland (southwest Flemish Cap), including the tissue from two specimens separated from their respective shell; and two paratypes are from the main basin of Bay d���Espoir, southern Newfoundland (Gagnon & Haedrich 2003). Table 3 summarizes the catalogue/accession information and basic morphological data for each specimen included in the type series. All specimens are deposited in the Mollusc Collection of the Canadian Museum of Nature; five of these were used to extract partial COI gene sequence datasets, which are available on GenBank. Description. Holotype (CMNML 097156): Complete specimen, left valve preserved dry (Fig. 14 A), right valve (posterior margin damaged) and tissue preserved in 70 % ethanol; nearly equivalved (see byssal notch below), thin, ovate with narrow hinge region (hinge length to shell width ratio = 0.43; Tab. 3), exterior light beige in colour, with whitish radial ribs in median portion of shell; anterior and posterior radial ribs most prominent, attenuating toward median region, becoming broader and flattened; at least 8���9 major growth lines irregularly interrupting radial ribs. Poorly developed anterior auricle, dorsally delineating lunule; posterior auricle extending from umbo and representing about 83 % of hinge length (Tab. 3). Lunule length 3.5 cm, representing 41 % of shell length, with weak inward curve. Byssal notch indistinct on left valve with lunule inner margin nearly straight, slightly gapping on right valve, particularly toward the dorsal region of the lunule. Shell moderately inflated with highest inflation point at first third of shell length. Shell interior translucent, glossy, whitish, with weak but demarcated muscle scars in the dorsoposterior region of the shell; pallial line weak. Hinge plate with deep, oblique, V-shape ligament pit extending from shell beak to mid-ventral edge of hinge plate. Hinge line delineating interior edge of hinge plate on either sides of ligament pit, nearly linear; ligament pit extending only slightly ventrally below hinge line; hinge length approx. 32 % of shell length; hinge plate approx. 0.5 cm high from beak to hinge line (about 5.2 % of shell length). Umbonal cavity present behind hinge plate. Soft tissue: mantle margin uniform and unfused, without siphon, bordered by short (contracted) tentacles. Foot small with broad, distal sole with deep byssal groove; three byssal threads attached anterodorsally to base of foot. Mouth bordered above and below by short palps, forming wide ���lips���; palps not connected to gills. In living animal, soft tissue bright orange in colour, with long tentacles extending from gaping mantle margin (Fig. 2). Character variations within type series: Tables 3 and 6 and Figure 7 present some of the morphometric variations between specimens. Shell thin, almost transparent in smallest specimen (CMNML 0 97162, Fig. 15), whitish to beige, translucent in some intermediate specimens (CMNML 0 97158, Fig. 3 D; CMNML 0 97157.1, Fig. 14 B) and thick, opaque with patchy whitish, beige to light brown exterior and white interior in oldest specimens (e.g., CMNML 0 92958, CMNML 097161.1); highest valve inflation point closer to middle of shell length in larger specimens (valve inflation to shell length ratio ranges from 0.15 to 0.26; Fig. 7 E), shell width to length ratio ranges from 0.74 to 0.84. Lunule of variable length relative to shell length with ratios ranging from 0.22 to 0.58 (Fig. 7 C). Byssal notch usually represented by slight gapping of right valve, occasionally on both valves (e.g., CMNML 097157.1). Hinge length to shell length ratio ranges from 0.24 to 0.32; hinge plate height to shell length ratio varies from 0.031 in smallest specimens (e.g., Figs. 14 B, 15 B) to 0.102 in older specimens (e.g., Fig. 16 B, D); hinge length to shell-width-ratio ranges from 0.30 to 0.43. Prominence of radial ribs on exterior of valves variable, faint in some specimens (e.g., CMNML 0 97160.2, CMNML 097161.1). The two specimens with well-preserved larval shell from The Gully and Beothuk Knoll (Tab. 5; Fig. 6) display a dome-shaped, subcircular prodissoconch (P 1), with a uniform glossy surface; shell type 2 D (or 2 C?) (Malchus & Sartori 2013). Their lengths vary between 241 and 261 ��m. A prodissoconch 2 region could not be clearly identified by light microscopy. Distribution. Only known from the material examined, off Nova Scotia, in The Gully, from 619 to 1241 m, and around Beothuk Knoll, southwest Flemish Cap, from 710 to 888 m, and from Newfoundland in Bay d���Espoir���s Main Basin, from approx. 400 to 785 m. See Figure 1 for map. Etymology. From the terms ���crypto���, meaning hidden or concealed, and ���adelphe���, meaning sister or sibling, referring to the very similar shell morphology between this northwest Atlantic species and Acesta excavata in the northeast Atlantic. Remarks. There is no DNA information available for the specimens collected by Gagnon & Haedrich (2003) in Bay d���Espoir, Newfoundland. However, according to our shell shape analysis, the specimens cluster with the Beothuk Knoll and The Gully specimens, which plot marginally outside the Acesta excavata cluster suggesting that they share close genetic affinities. The specimens from the Azores also cluster along with the Newfoundland and Nova Scotia specimens in the shell shape analysis, and may also represent A. cryptadelphe sp. nov. Further genetic work on Azorean specimens is required to test that hypothesis. The molecular data indicate that the Acesta species, including A. cryptadelphe sp. nov., each form a monophyletic clade (Figs. 12, 13). The specimens from Newfoundland (Beothuk Knoll) and Nova Scotia (The Gully) have a low genetic divergence (average 0.012) comparable to that of other Acesta species (range 0.003 to 0.012), and with divergence from other Acesta species an order of magnitude greater; ranging from 0.103 (A. mori) to 0.166 (A. sphoni). Habitat and species association. In the northwest Atlantic (Fig. 1), all specimens were found associated with rocky substrates below 400 m water depth, either on isolated outcrops, under overhangs or on rock walls. The first two specimens of giant file clams found in Bay d���Espoir, Newfoundland, were associated with a near-vertical underwater cliff and isolated outcrops at depths ranging from 400 to 800 m (Gagnon & Haedrich 2003). A manned diving excursion with a submersible along two vertical transects of this fjord���s rock walls (Goblin Head; Haedrich & Gagnon 1991) revealed large numbers of Acesta specimens but none of the typical cold-water coral association (i.e., Paragorgia arborea, Primnoa resedaeformis, Lophelia pertusa and Madrepora oculata (Linnaeus), Desmophyllum Ehrenberg. In The Gully, Acesta specimens occur on steep cliffs and other rock surfaces, in association with Desmophyllum dianthus (Esper) (Fig. 2 B), Paramuricea Koelliker, and occasionally in the vicinity of Primnoa resedaeformis (Gunnerus) (Kenchington et al. 2014). Around Beothuk Knoll, Murillo et al. (2011) reported Paragorgia arborea and Desmophyllum dianthus whereas Primnoa resedaeformis and Anthothela grandiflora (M. Sars) are present within Flemish Pass, just north of Beothuk Knoll., Published as part of Gagnon, Jean-Marc, Kenchington, Ellen, Port, Antony, Anstey, Lynne J. & Murillo, Francisco Javier, 2015, Morphological and genetic variation in North Atlantic giant file clams, Acesta spp. (Bivalvia: Limidae), with description of a new cryptic species in the northwest Atlantic, pp. 151-180 in Zootaxa 4007 (2) on pages 174-177, DOI: 10.11646/zootaxa.4007.2.1, http://zenodo.org/record/235013, {"references":["Gagnon, J. - M. & Haedrich, R. L. (2003) First record of the European giant file clam, Acesta excavata (Bivalvia: Pectinoidea: Limidae), in the northwest Atlantic. The Canadian Field-Naturalist, 117, 440 - 447. Available from: http: // canadianfieldnaturalist. ca / index. php / cfn / article / viewFile / 748 / 748 (accessed 10 August 2015)","Malchus, N. & Sartori, A. F. (2013) Part N, Revised, Volume 1, Chapter 4: The early shell: Ontology, features and evolution. Treatise Online, 61, 1 - 144.","Haedrich, R. L. & Gagnon, J. - M. (1991) Rock wall fauna of Newfoundland Fjords. Continental Shelf Research, 11, 1199 - 1208. http: // dx. doi. org / 10.1016 / 0278 - 4343 (91) 90097 - P","Kenchington, E., Cogswell, A., MacIsaac, K., Beazley, L., Law, B. & Kenchington, T. (2014) Limited depth zonation among bathyal epibenthic megafauna of the Gully submarine canyon, northwest Atlantic. Deep-Sea Research II, 104, 67 - 82. http: // dx. doi. org / 10.1016 / j. dsr 2.2013.08.016","Murillo, F. J., Duran Munoz, P., Altuna, A. & Serrano, A. (2011) Distribution of deep-water corals of the Flemish Cap, Flemish Pass and the Grand Banks of Newfoundland (northwest Atlantic Ocean): interaction with fishing activities. ICES Journal of Marine Science, 68, 319 - 332. http: // dx. doi. org / 10.1093 / icesjms / fsq 071"]}

Here we report the first study of clearance rate and respiration rate of a deep living bivalve, Acesta excavata (J.C. Fabricius, 1779) (Mollusca: Limidae). We found that A. excavata had extreme values both for clearance and respiration rates compared to other bivalves. It has the second largest clearance rate ever reported, 13.36 l h − 1 g − 1 , and the second lowest value of respiration rate, 0.12 ml O 2 h − 1 g − 1 . The gill area of 7063 mm 2 g − 1 is one of the largest found in bivalves so far. We suggest that these values indicate a physiological adaptation to the low and irregular food supply in the deep sea rather that a specific adaptation to depth.

Knowledge about the marine malacofauna in the Magellan Region has been gained from many scientific expeditions that were carried out during the 19th century. However, despite the information that exists about molluscs in the Magellan Region, there is a lack of studies about assemblages of molluscs co-occurring with macroalgae, especially commercially exploitable algae such as Gigartina skottsbergii, a species that currently represents the largest portion of carrageenans within the Chilean industry. The objective of this study is to inform about the richness, systematics, and distribution of the species of molluscs associated with natural beds in the Strait of Magellan. A total of 120 samples from quadrates of 0.25 m2 were obtained by SCUBA diving at two sites within the Strait of Magellan. Sampling occurred seasonally between autumn 2010 and summer 2011: 15 quadrates were collected at each site and season. A total of 852 individuals, corresponding to 42 species of molluscs belonging to Polyplacophora (9 species), Gastropoda (24), and Bivalvia (9), were identified. The species richness recorded represents a value above the average richness of those reported in studies carried out in the last 40 years in sublittoral bottoms of the Strait of Magellan. The biogeographic affinity indicates that the majority of those species (38%) present an endemic Magellanic distribution, while the rest have a wide distribution in the Magellanic-Pacific, Magellanic-Atlantic, and Magellanic-Southern Ocean. The molluscs from the Magellan Region serve as study models for biogeographic relationships that can explain long-reaching patterns and are meaningful in evaluating possible ecosystemic changes generated by natural causes or related to human activities.

The previously unclear taxonomic status of the high-Antarctic bivalve Limatula ovalis Thiele, 1912 and the sub-Antarctic L. pygmaea (Philippi, 1845) was investigated using molecular techniques (18S rDNA, 16S rDNA, ITS-1). L. ovalis and L. pygmaea were recovered as sister taxa, and L. hodgsoni (Smith, 1907) as their sister, supporting the subgenus Antarctolima Habe, 1977. Various different molecular clock calculations placed the timing of the L. ovalis/pygmaea divergence (1.36–8.03 MYA with 16S rDNA, 6.81–19.12 MYA with 18S rDNA, 0.24–2.87 MYA with ITS-1) well after the formation of the Antarctic Polar Front (23.5 MYA, APF), indicating a more recent speciation process. The vicariance hypothesis that the APF is a barrier for geneflow favouring speciation processes in the Southern Ocean has to be questioned.

Hryniewicz, Krzysztof, Little, Crispin T.S., Nakrem, Hans Arne (2014): Bivalves from the latest Jurassic-earliest Cretaceous hydrocarbon seep carbonates from central Spitsbergen, Svalbard. Zootaxa 3859 (1): 1-66, DOI: http://dx.doi.org/10.11646/zootaxa.3859.1.1

Pseudolimea arctica (Zakharov, 1966) (Figure 10 P���R) 1966 Lima (Pseudolimea) arctica sp.���Zakharov, p. 62, pl. 16, figs. 6���11. 1966 Pseudolimea aff. parallela Orbigny [sic]���Zakharov, p. 64, pl. 16, fig. 12. 1982 Pseudolimea cf. arctica (Zakharov) ���F��rsich, p. 61, fig. 25 A. 2011 Pseudolimea sp. ���Hammer et al., fig. 7k, tab. 2. Material examined. 18 specimens, all single valves; shells and internal moulds. See Appendix 1 for the list of specimens. Dimensions. 18.1���34 mm in length, 16���31.5 mm in height. See Figure 12 A���C and Appendix 2I for details. Diagnosis. A Pseudolimea with up to 35 radial, v-shaped primary ribs with weaker ribs on anterior and posterior parts of the shell. Inter-rib spaces with single smaller riblet. Description. Shell small to medium, up to 34 mm long and 31.5 mm high. Shell oval, inequilateral, posteroventrally elongated, triangular, with umbonal angle around 90��. Anterodorsal margin weakly convex, passing abruptly into broadly arcuate ventral margin. Posteroventral margin tightly arcuate, passing gently into straight and long posterodorsal margin. Posterodorsal margin about twice length of anterodorsal margin. Hinge line straight, around quarter shell length, with smaller anterior and larger posterior auricles not projecting beyond shell outline. Umbo small, weakly prosogyrate beak projecting beyond hinge line. Shell ornament of 24���35 v-shaped primary ribs with intercalated weaker secondary riblets in interspaces. Radial ornament dissected by weak, commarginal growth lines visible on outer shell surface only. Internal moulds show only rounded primary ribs. Ribs start on umbo, getting progressively stronger towards ventral margin; strongest on shell mid-flank, becoming weaker close to anterior and posterior shell margins. Ribs fade and then disappear on shell anterior where ventral curvature bends up towards anterodorsal margin; on posterior margin ribs disappear where posteroventral curvature passes into straight posterodorsal shell margin. Dorsal margins and auricles ornamented by concentric growth lines only. Dentition not observed. Remarks. We include this species in the Siberian Kimmeridgian���Volgian taxon Pseudolimea arctica (Zakharov, 1966), based on its external shell proportions and the number of ribs. Comparison of shell measurments (Fig. 12 A���C) shows that the Svalbard Pseudolimea specimens and P. arctica have an almost identical shell shape. The Svalbard specimens are more densely ribbed than P. arctica (Zakharov, 1966). However, more sparsely ribbed Svalbard specimens form a morphological continuity with the densely ribbed specimens of P. arctica, so there is no reason to separate them on rib number. Coarsely ribbed P. arctica specimens from Siberia overlap in rib number with P. multicostata F��rsich, 1982, from England, Greenland and Siberia (Tab. 10, Zakharov 1966; F��rsich 1982; Kelly 1984) and with Lima (Mantellum) parallela (J. Sowerby, 1812) from the Aptian���Albian of England (Woods 1904), which has no more than 23 ribs. However, both P. multicostata and P. parallela are more elongated than P. arctica from Siberia and Svalbard (Fig. 12 B, C). Interestingly, Lima (Pseudolimea) aff. parallela (J. Sowerby, 1812) non (d���Orbigny), from the upper Ryazanian of Siberia (Zakharov 1966) has 27 ribs and similar shell proportions to P. arctica , but not to P. parallela as shown by the data of Woods (1904), and should therefore also be included into P. arctica. Occurrence. Seep 9 (uppermost Ryazanian), Slottsm��ya Member, Svalbard (Tab. 1). It also occurs in the Kimmeridgian, Volgian and possibly also the Upper Ryazanian of Siberia (Zakharov 1966) and the Volgian of Greenland (F��rsich 1982). Palaeoecology. Pseudolimea arctica probably took advantage of hard substrates present in the seeps, such as exposed carbonate and other shells, for byssal attachment. Modern limids can be found both in shallow and deep marine environments (Allen 2004). They are suspension feeders, byssally attached to rocks, shells and marine plants. They can also form ���nests��� composed of mucus, byssal threads and various incorporated hard elements if the substrate proves unsuitable for byssal attachment (Merrill & Turner 1963). Some species possess the ability to swim by clapping their valves, and others are able to relocate using their foot and byssus (Mikkelsen & Bieler 2008). Unlike other monomyarian bivalve families, limids are not pleurothetic, i.e. they do not rest on one of the valves, but orient their commissure perpendicular to the substrate (Mikkelsen & Bieler 2008). The extinct genus Pseudolimea probably behaved in the same way. No association between limids and symbiotic bacteria has been recorded to date, but Acesta oophaga J��rnegren, Schander & Young, 2007 in J��rnegren et al. 2007, from hydrocarbon seep environments in the Gulf of Mexico has morphological adaptations for feeding on the eggs of the tubeworm Lamellibrachia luymesi van der Land & N��rrevang, 1975. It has a folded posterodorsal shell margin that surrounds the tubeworm plume, where eggs are being released from the tube (J��rnegren et al. 2005). No such adaptation has been recorded in any species of Pseudolimea., Published as part of Hryniewicz, Krzysztof, Little, Crispin T. S. & Nakrem, Hans Arne, 2014, Bivalves from the latest Jurassic-earliest Cretaceous hydrocarbon seep carbonates from central Spitsbergen, Svalbard, pp. 1-66 in Zootaxa 3859 (1) on pages 28-29, DOI: 10.11646/zootaxa.3859.1.1, http://zenodo.org/record/4930112, {"references":["Zakharov, V. A. (1966) Late Jurassic to early Cretaceous bivalve mollusks of northern Siberia. Nauka, Moscow, 189 pp, 38 pls. [in Russian]","Fursich, F. T. (1982) Upper Jurassic bivalves from Milne Land, East Greenland. GrOnlands Geologiske UndersOgelse, 144, 1 - 126.","Kelly, S. R. A. (1984) Bivalvia of the Spilsby Sandstone and the Sandringham Sands (Late Jurassic - Early Cretaceous) of Eastern England. Part 1. Palaeontographical Society Monographs, 137, 1 - 94, pls. 1 - 20.","Sowerby, J. (1812) The Mineral Conchology of Great Britain 1 (1), J. Sowerby, London, i - vii, 9 - 32, pls. 1 - 9. http: // dx. doi. org / 10.5962 / bhl. title. 14408","Woods, H. (1904) A monograph of the Cretaceous Lamellibranchia. Vol. II. Palaeontographical Society Monographs, 58, 1 - 56, pls. 1 - 7.","Allen, J. A. (2004) The Recent species of the genera Limatula and Limea (Bivalvia, Limacea) present in the Atlantic, with particular reference to those in deep water. Journal of Natural History, 38, 2591 - 2593. http: // dx. doi. org / 10.1080 / 00222930310001647442","Merrill, A. S. & Turner, R. D. (1963) Nest building in the bivalve genera Musculus and Lima. The Veliger, 6, 55 - 59.","Mikkelsen, P. M. & Bieler, R. (2008) Seashells of Southern Florida. Living marine mollusks of the Florida Keys and adjacent regions. Bivalves. Princeton University Press, Princeton & Oxford, 503 pp.","Jarnegren, J., Schander, C., Sneli, J. - A., Ronningen, V. & Young, C. M. (2007) Four genes, morphology and ecology: distinguishing a new species of Acesta (Mollusca; Bivalvia) from the Gulf of Mexico. Marine Biology, 152, 43 - 55. http: // dx. doi. org / 10.1007 / s 00227 - 007 - 0651 - y","Van der Land, J. & Norrevang, A. (1975) The systematic position of Lamellibranchia (Annelida, Vestimentifera). Zeitschrift fur Zoologische Systematik und Evolutionforschung, 1975, 86 - 101.","Jarnegren, J., Tobias, C. R., Macko, S. A. & Young, C. M. (2005) Egg predation fuels unique species association at deep-sea hydrocarbon seeps. Biological Bulletin, 209, 87 - 93. http: // dx. doi. org / 10.2307 / 3593126"]}

The cosmopolitan, Jurassic to Recent, bivalve Acesta (Limidae) is documented from Australian Cretaceous (upper Albian) rocks in the lowermost section of the Mackunda Formation of Queensland. These specimens from Landsborough Downs, Flinders Shire, represent an endemic new species, herein named Acesta (Acesta) backae n. sp. Acesta (A.) backae n. sp. was a shallow-water suspension feeder that inhabited the Cretaceous Australian epicontinental sea of the Great Artesian Basin. Although hinge details of Acesta (A.) backae n. sp. are wanting, this new taxon is most closely allied with Acesta? sp. of the Miria Formation of Western Australia and can clearly be discriminated from other Cretaceous Austral forms.