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Astrolirus patricki sp. nov. urn:lsid:zoobank.org:act: 0F238379-CD10-4E51-A74A-0FEF055D72A5 (Figs. 14) Diagnosis. Arms 7, robust. Intercostal integument densely covered by irregular, abutting plates. No syzygy between proximal arm plates. The first pair of adambulacral plates separated byapair of marginal plates. Alargeinterradial plateabove thefirst marginal plates, visible from the abactinal side, covered by scattered spinelets. Mouth spines and proximal adambulacral spines robust, densely distributed. Suboral spines 3 4; subambulacral spines 1 2, proximal ones truncate, capitate. One lateral spine to each adambulacral plate, starting from about the 8th. Apair of gonads to each arm. Etymology. The name is originatedfrom the character ‘‘Patrick Star’’ inthe famous cartoon ‘‘SpongeBob Squarepants’’, who always spends time with his best friend ‘‘SpongeBob’’, a benthic sponge. Since all specimens of the new species were observed in situ living on sponges (Fig. 1), it was name by Patrick to reflect this curious relationship. Material examined. Holotype, RSIOAS044 (Fig. 1A), 7 arms, of which 3 attached to the disk, others detached. r = 7.5 mm, the longest broken arm measures 153 mm without the missing tip. Length of genital area 35 mm, broadest part of arm measures 7 mm. Paratype RSIOAS028 (Fig. 1B), 7 arms, including 3 regenerating ones, all attaching to the disk; r = 7 mm, the longest arm measures 153 mm, R /r = 21.9; length of genital area 36 mm, broadest part of arm measures nine mm wide. Paratype RSIOAS003 (Fig. 1C), 7 arms, all arm detached from the disk; r = 10 mm, R = 190 200 mm, R /r = 19 20; length of genital area about 50 mm, broadest part of arm 9 10 mm, at 15 20 mm from the disk. Paratype RSIOAS052 (Fig. 1D), 7 arms, r = 7.5 mm, the longest arm measures 168 mm, R /r = 22.4. Paratype MBM 286625 (Fig. 1E), 7 arms, r = 7.5 mm, R = 171 mm, R /r = 22.8; length of genital area about 33 mm, broadest part of arm 7.5 mm. Description of the holotype. Arms 7. Disk thick, elevated from the plane of arms (Figs. 2A 2C). Abactinal surface of disk covered by small rounded plates (Fig. 2G) bearing multiple sharp, thin spinelets, with few scattered pedicellariae between and at the base of the spinelets (Figs. 2C, 2F). Madreporite body locates at the margin of the disk, elliptical with a curved rift in the center (Fig. 2C). Papulae absent. Abactinal surface of arm within genital area densely covered by abutting plates of irregular scale forms. Pedicellariae scattered in the proximal region connecting disk and the genital area, not forming costae (Fig. 2C). Costae present within the genital area, about 30 in number; costae thin, densely located (two to each adambulacral plate), composed of raised band of pedicellariae (Figs. 2D 2E). Beyond the genital area, pedicellariae forms bands wider than costae, two to each adambulacrals (Fig. 2H). Apair of gonads to each arm. Each gonad with 3 6 oval pedals (Fig. 3G). Adambulacral plate in proximal area subquadrate, elongated in middle and distal part of the arms (Fig. 4). Proximally the ambulacral groove almost completely concealed by adambulacral spines (Fig. 4). The first pair of adambulacral plates on adjacent arms entirely separated by a pair of marginal plates (Figs. 3C 3D). No syzygy between proximal plates. The first pair of marginal plates unit closely with an interradial plate (Fig. 3D). Interradial plate large, nearly naked, extending to the abactinal side of disk (Fig. 2C). Proximally 2 3 marginal plates well-developed, present on the lateral side of the arm (Fig. 2C). The following marginal plates degrade to a line of protuberances on the side and corresponding to each adambulacral plates, bearing long lateral spine. Lateral spine present from about the 8th adambulacral plate, one to each plate (Figs. 3F, 4). The longest measures 15 20 mm. Adambulacral plate armature includes: (1) 2 subambulacral spines and 1 aboral furrow spine, forming a diagonal row; the outer subambulacral spine usually the largest and most robust; (2) 1 adoral furrow spine, thinner than the aboral one (Fig. 4). The first pair of adambulacral plate bear a diagonal line of 4 5 spines, two on the surface of the plate, and 2 3 smaller ones on the distal furrow corner (Figs. 3B 3D). At middle and distal part of arm, the number of subambulacral spine on each adambulacral plate reduces to 1 (Fig. 4). Proximal subambulacral spinestruncate form, capitate (Fig. 3C). The furrow spines become shorter and thinner on distal plates. All adambulacral spines bear pedicellariae, leaving only the tip of the spines naked. Mouth plate large, bearing 3 4 robust suboral spines, forming a diagonal line, similar in form with the proximal subambulacral spines (Figs. 3A 3B); 2 small furrow spines present on the aboral corner of the plate, close to the first adambulacral plate; on the oral margin, the plate bears 2 very minute spines, one pointing to the actinostome and one pointing rather to the furrow, forming a sharp angle with the former. All oral spines bear pedicellariae. Variations in paratypes. In the paratypes, adambulacral plates at middle and distal part of arm bear equal number of spines as the proximal adambulacral plates (Fig. 3F), instead of having one less subambulacral spine as in the holotype. In several undeveloped arms in the paratypes, gonads were not spotted. The shape and size of the marginal and interradial plates vary slightly in paratype RSIOAS003 (Fig. 3E). Coloration. Color in life orange (Figs. 1, 2A 2B). Distribution. Known from the northwestern Pacific Ocean, on seamounts, 1458 2125 m depth. Molecular and phylogenetic results. COI K2P distances between specimens of A. patricki sp. nov. are less than 0.003, which are considered to be intraspecific distances. A. patricki sp. nov. is closest to Brisinga species, with distances between 0.123 0.159. The topology of the Bayes tree is shown in Fig. 5 and the nodes marked by black dots are support by both Bayes tree and ML tree. This tree is overall in line with results of the previous studies (Mah & Foltz, 2011; Zhang et al., 2019). Remarks for A. patricki sp. nov. Types of A. patricki sp. nov. from different seamounts show little intraspecific divergences other than size and adambulacral spine number. The difference between A. patricki sp. nov. and the type species of the genus, A. panamensis, are listed in Table 2. Although both species are characterized by the presence of abactinal plates, in A. panamensis the plates locate between the transverse costae, whereas in A. patricki sp. nov. a mosaic of abutting plates forms the abactinal arm skeleton. The two species further differ in arm number, adambulacral spine number and distribution, as well as the number of genital organs. It should be noticed that, in Ludwig’s original description of A. panamensis, ‘‘several, consecutive pairs of branched gonads on each arm (4 5 in one male specimen)’’ were recorded, each branch has their own gonopore (Ludwig, 1905), but later when Fisher established the new genus, he described Astrolirus as having 2 4 gonads to each arm (Fisher, 1917). Whether this new description resulted from a reexamination of the type specimens was not clearly indicated (Fisher, 1917). Therefore, in this study we choose to follow Ludwig’s original descriptions when evaluate the differences between the new species and A. panamensis. In addition, A. patricki sp. nov. ischaracterized bya largenumber of suboralspines (3 4), whereas in A. panamensis, only 1 suboral spine present on each oral plate. Interestingly, in A. panamensis, some large specimens (r = 13 or 10.5 mm) have the 2 suboral spines on a pair of oral plates covered in a same membrane (Ludwig, 1905). This characteristic has only been reported in Brisinga andamanica Wood-Mason & Alcock, 1891 and Brisinga bengalensis Wood-Mason & Alcock, 1891 (Alcock, 1893), whose biological function is not clear., Published as part of Zhang, Ruiyan, Zhou, Yadong, Xiao, Ning & Wang, Chunsheng, 2020, A new sponge-associated starfish, Astrolirus patricki sp. nov. (Asteroidea: Brisingida: Brisingidae), from the northwestern Pacific seamounts, pp. e 9071 in PeerJ 8 on pages 5-10, DOI: 10.7717/peerj.9071, http://zenodo.org/record/4621673, {"references":["Mah C, Foltz D. 2011. Molecular phylogeny of the Forcipulatacea (Asteroidea: Echinodermata): systematics and biogeography. Zoological Journal of the Linnean Society 162 (3): 646 660 DOI 10.1111 / j. 1096 - 3642.2010.00688. x.","Zhang R, Wang C, Zhou Y, Zhang H. 2019. Morphology and molecular phylogeny of two new species in genus Freyastera (Asteroidea: Brisingida: Freyellidae), with a revised key to close species and ecological remarks. Deep Sea Research Part I: Oceanographic Research Papers 154: 103163 DOI 10.1016 / j. dsr. 2019.103163.","Ludwig H. 1905. Asteroidea. Memoirs of the Museum of Comparative Zoology at Harvard 32: 97 100 [in Germany].","Fisher WK. 1917. LI. New genera and species of Brisingidae. Annals and Magazine of Natural History, Series 8, 20 120: 418 431.","Alcock A. 1893. XV Natural history notes from HM Indian marine survey Steamer ' Investigator, ' Commander CF Oldham, RN, commanding. Series II. (7) An account of the collection of deep-sea Asteroidea. Journal of Natural History 11 (62): 73 121 DOI 10.1080 / 00222939308677478."]}

Genus Astrolirus Fisher, 1917 Diagnosis to Genus. Intercostal integument covered by thin plates; the first pair of adambulacral plates do not touch by their interradial faces, but are separated by a pair of marginal plates; first pair of marginal plates unit closely with a large interradial plate in the interradial faces., Published as part of Zhang, Ruiyan, Zhou, Yadong, Xiao, Ning & Wang, Chunsheng, 2020, A new sponge-associated starfish, Astrolirus patricki sp. nov. (Asteroidea: Brisingida: Brisingidae), from the northwestern Pacific seamounts, pp. e 9071 in PeerJ 8 on page 4, DOI: 10.7717/peerj.9071, http://zenodo.org/record/4621673, {"references":["Fisher WK. 1917. LI. New genera and species of Brisingidae. Annals and Magazine of Natural History, Series 8, 20 120: 418 431."]}

Styracaster yapensis sp. nov. (Figs.1–6) Etymology. Name after the type locality Yap Trench. Description. Rays five, short, thin, rounded, and of uniform thickness throughout. R/r = 2–3, 35/ 17 mm in the holotype and 30/ 10 mm in the paratype. Disk conspicuously convex. Interbrachial arcs broad (Figs. 2A, 2B). Abactinal area uniformly covered with numerous, scattered granular plates, inclusive of the arm base, where they are obscured by a thin membrane (Figs. 2A, 2C). Plates spineless. Paxillae absent. In the holotype small projection present at disk center, surrounded by a small circle of enlarged or elongated granular plates which are almost pseudo-paxilliform (Fig. 2D). No projection in the paratype, there is a central pore at disk center (Fig. 2E). Madreporite large, sub-circular, located on the edge of the disk, in close proximity to the only fully developed cribriform organ and separated from it by a narrow groove. Madreporite of a diameter about the upper length of the adjoining cribriform organ (2.8 mm). The striae radiating from a proximal point (Figs. 6A, 6C). Superomarginal plates 15–16 in number, counted from the midpoint of interradius to the arm tip, joining at the arm midline from about the sixth opposite pair. Superomarginal plates longer than higher on the disk and subquadrate on the arms (Figs. 3A–D, 6A–D). On the arm midline, 3–4 thin, tapering abactinal spines placed on the proximal five to six joining superomarginals (Figs. 3A, 3C). Distally occasionally some protuberances on one or both of the paring superomarginals (Figs. 3B, 3D). The abactinal spines rather transparent and delicate; the innermost one the largest and the most robust, the longest reaching 2.5 mm. The number and location of abactinal spines and protuberances varying in different arms (Figs. 3A–D). Inferomarginal and superomarginal plates generally corresponding in number and length, only in one or two interradii where an additional inferomarginal or superomarginal plate appears in the middle of the arm interradius (Fig. 6B). The inferomarginals of the disk about as long and high as the accompanying superomarginals (Figs. 6A– D), but slightly lower than the superomarginals in the arm (Figs. 3A–B) (in the paratype the inferomarginals are almost twice or three times lower than the superomarginals) (Figs. 3C–D). All inferomarginal plates unarmed. Only one fully developed cribriform organ in the madreporite interradius, in close proximity to the madreporite and separated from it by a narrow groove (Fig. 6A, 6C). Cribriform organ subtrapezoid in form, extending from the upper margin of the superomarginal to the lower margin of the inferomarginal, covering the whole height of the interradial margin, not visible from the abactinal side (Figs. 6A, 6C). The paratype has two more rudimentary cribriform organs on each side of the fully developed one. The rudimentary cribriform organs are of a triangular form, which are much smaller than the fully developed one and not extending to the low margin of the inferomarginal (Fig. 6C). No cribriform organ visible in other interradii in the holotype (Figs. 6B); 1–3 lines of small papillae between the central 2–3 superomarginals exist in some interradii in the paratype (Fig. 6D). Terminal plate large, with 4–6 sharply pointed terminal spines. 2(–3) dorsal terminal ones placed on the end of the arm midline and 2(–3) distal ones placed on a lower level at the extremity of the furrow. The terminal spines are generally of varied size; the longest one almost as long as the first abactinal spine (Figs. 3E–G). Ventrolateral areas expansive, covered with a thin transparent membrane (Fig. 4E, 5B). Ventrolateral plates naked, elongate and very delicate, not uniformly arranged in tangential and radiating series, not extending to the arms. In most interradii, the plates are fairly indiscernible. Ambulacral furrows narrow and entirely closed in by the adambulacral spines (Figs. 2B, 4C, 5D). Tube feet in 2 rows, with no terminal suckers. Adambulacral plates 22–24 in number. The proximal ones bearing three pointed furrow spines, with the largest on the adoral side (Fig. 4D). The spines in the paratype slightly flattened (Figs. 5B– C). On arm each adambulacrals bearing 2–3 furrow spines (Figs. 4C, 5D). Only one subambulacral spine present on each adambulacral plate in the holotype; the paratype with 2–3 subambulacral spines on each proximal adambulacral plate and 1–2 on each distal plate (Figs. 4C–D, 5B–D). Mouth plates large and very conspicuous (Figs. 4A–B, 5A). Two proximal spines to each pair of mouth plates, pointing to the actinostome. Proximal spines relatively large, thicker than the furrow spines. Each mouth plate carrying four subequal spinelets on the margin and about six suboral spinelets or granules on the surface. The marginal spinelets conspicuously smaller than the furrow spines. Peristome wide and conspicuous. Coloration. Color in life grayish white. Distribution. Styracaster yapensis sp. nov. is known from two dives at the Yap Trench in the western Pacific. Both specimens are collected from fine-grained muddy sediments from a depth between 6377 and 6575 m. Remarks. Madsen classified Styracaster species into three groups, represented by S. horridus Sladen 1883, S. chuni Ludwig 1907 and S. armatus Sladen 1883 respectively (Madsen 1961). The former two groups are characterized by the paxillae-covered abactinal surface, and the latter two by relatively small R/ r ratio (usually 3). Styracaster yapensis sp. nov. falls in the third group, which includes S. armatus (Sladen, 1883), S. monacanthus (Ludwig, 1907) and S. clavipes (Wood-Mason & Alcock, 1891), sharing the characteristics of a non-paxillae covered abactinal surface and small R/ r ratio. Styracaster yapensis sp. nov. is distinguished from the latter species by the unique form of abactinal armature and rudimentary cribriform organs. In S. yapensis sp. nov., granular plates are scattered on the whole abactinal surface with spines or spinelets absent, whereas in S. armatus and S. clavipes, the abactinal surface is covered by small rounded plates each bearing 1–2 spines, and in S. monacanthus, granular plates each bear a blunt spinelet; S. yapensis sp. nov. has 0–3 rudimentary cribriform organs in each interradius, which consist of only a few lines of small papillae, and one well-developed cribriform organ only at the madreporite interradius, which is large and extending across the whole height of vertical suture, whereas S. armatus, S. clavipes and S. monacanthus have 3, 5 and 5* well-developed cribriform organ in each interradius respectively. Mironov et al. (2016) suggested a pronounced trend to simplification of the morphology in Porcellanasteridae, including the decreasing in number of respiratory organs, cribriform organs and body size, as an adaptation to deep-sea environments. S. yapensis sp. nov. has the fewest number and the most degraded form of cribriform organ within the genus, which might as well be an adaptive strategy for its life in each interradius respectively. (* S. monacanthus was described to …having 7 cribriform organs.) Mironov et al. (2016) suggested a pronounced trend to simplification. The type locality of S. armatus is close to the type locality of S. yapensis sp. nov., but much shallower (near the Caroline Islands at 3384 m depth). The similar adambulacral and mouth plate armature of the two species may suggest a close affinity. Styracaster yapensis sp. nov. is further distinguished from S. armatus by 1) abactinal surface that entirely covered by uniform granular plates, extending onto the arm bases (in S. armatus there are naked spaces at arm bases); 2) fairly conspicuous terminal plates with 4–6 spines (R=35 and 30 mm) (in S. armatus the terminal plates are inconspicuous, with 3 spines (R= 38–39 mm)); 3) the number and form of marginal plates. The number of superomarginal plates on each arm in S. armatus (RS. yapensis sp. nov. (R=35 and 30 mm, R/r =2 and 3) have 15–16 superomarginal plates on each arm, joining at the 6th opposite pair. This indicates much shorter superomarginals in the new species, at least interradially, which is not likely to be a variation related to growth stage. In addition, the form of superomarginals in S. yapensis sp. nov. changes from longer than higher on disk to subquadrate on arm, whereas in S. armatus, the superomarginals are subquadrate on disk and become lower and rectangular on arm. S. yapensis sp. nov. is the second porcellanasterid species from the Yap Trench. Previously Porcellanaster ivanovi was found from there at 8560–8720 m depth (Belyaev, 1985). S. yapensis sp. nov. is readily distinguished from S. monacanthus by 1) subambulacral and suboral spines (present in the former, absent in the latter); 2) number of abactinal spines on arm (3–4 to 1); 3) number of and terminal spines (4–6 to 3). Gene bank accession numbers: See Table 2.

Zhang, Ruiyan, Zhou, Yadong, Lu, Bo, Wang, Chunsheng (2017): A new species in the genus Styracaster (Echinodermata: Asteroidea: Porcellanasteridae) from hadal depth of the Yap Trench in the western Pacific. Zootaxa 4338 (1): 153-162, DOI: https://doi.org/10.11646/zootaxa.4338.1.8