Samadinia livermorii (Wood-Mason in Wood-Mason & Alcock, 1891)

Ahyong, Shane T., Lee, Bee Yan & Ng, Peter K. L., 2023, Spider Crabs of the Samadinia pulchra complex (Crustacea: Decapoda: Epialtidae), Records of the Australian Museum (Rec. Aust. Mus.) 75 (4), pp. 343-356 : 351-355

Samadinia livermorii (Wood-Mason in Wood-Mason & Alcock, 1891)

Figs 1 , 5C, D , 6 , 7I, J

Anamathia Livermorii Wood-Mason in Wood-Mason & Alcock, 1891: 260 (type locality: Investigator Station 56, between North and South Sentinel Island, Andaman Islands).—Alcock, 1894: 401.

Anamathia livermorei [sic].—Anonymous, 1891: 56.— Huys et al., 2014: 26.

Scyramathia livermorii . —Alcock & Anderson, 1895: pl. 14 fig. 3.

Scyramathia pulchra . —Alcock, 1895: 202–203.—Alcock, 1899: 1 (list), 4 (list), 5 (list), 52.— Doflein, 1904: 84, pl. 27 fig. 12.— Rathbun, 1911: 194 (list), 250 [not Amathia (Amathia) pulchra Miers in Tizard, Moseley, Buchanan & Murray, 1885].

Rochinia pulchra . — Richer de Forges & Ng, 2013: 468, figs 1A, B, 2B (in part).— Muñoz et al., 2021: 33, figs 9D, 12 [not Amathia (Amathia) pulchra Miers in Tizard, Moseley, Buchanan & Murray, 1885].

Samadinia livermorii . — Lee et al., 2023: 328.

Material examined. Andaman Sea: NHM 1896.5.14.7, 1 ovigerous female (cl 18.1 mm, pcl 12.3 mm, cw 8.0 mm), 13°47'30"N 92°36'00"E, 561 fm (1027 m), RIMSS Investigator stn 112, 7 November 1890. Indonesia: ZRC 2020.0032 , 2 ovigerous females (cl 17.5 mm, pcl 12.5 mm, cw 8.5 mm; cl 18.8 mm, pcl 12.7 mm, cw 8.6 mm), Sunda Strait between Tabuan Island and Sumatra , 5°45.126–45.225'S 104°51.080–51.710'E, 425–442 m, SJADES 2018 stn CP08, 25 March 2018; ZRC 2020.0033 , 1 spent female (cl 23.1 mm, pcl 13.6 mm, cw 9.2 mm), 1 ovigerous female (cl 24.1 mm, pcl 14.4 mm, cw 10.2 mm), S of Panaitan Island, Sunda Strait , 6°46.739–45.924'S 105°09.239–08.360'E, 559–571 m, SJADES 2018 stn CP23, 27 March 2018; ZRC 2020.0034 , 1 male (cl 19.3 mm, pcl 11.5 mm, cw 7.4 mm; with rhizocephalan), S of Panaitan Island, Sunda Strait , 6°50.185–50.923'S 105°10.353–10.776'E, 876–937 m, SJADES 2018 stn CP25, 27 March 2018; MZB, 2 males (cl 24.2 mm, pcl 14.1 mm, cw 10.1 mm; cl 21.3 mm, pcl 14.0 mm, 9.7 mm), 1 juvenile female (pcl 6.9 mm, cw 4.5 mm), S of Pameungpeuk, Indian Ocean , 7°47.972–48.257'S 107°45.298–45.706'E, 476–530 m, SJADES 2018 stn CP47, 1April 2018; ZRC 2020.0035 , 1 male (cl 28.0 mm, pcl 16.4 mm, cw 14.4 mm; with epicaridean), Pelabuhanratu Bay, Indian Ocean , 7°04.874–05.348′S 106°25.396–25.044′E, 569–657 m, coll. SJADES 2018, stn CP51, 2 April 2018; MZB, 1 male (cl 28.7 mm, pcl 15.7 mm, cw 11.0 mm), same; MZB, 2 males (cl 24.3 mm, pcl 15.1 mm, cw 10.5 mm; cl 19.4 mm, pcl 13.2 mm, cw 8.5 mm), 1 ovigerous female (cl 20.8 mm, pcl 13.3 mm, cw 9.3 mm), S of Tanjong Boyongkareuceng, Indian Ocean ,7°42.912–43.255'S 107°36.559–37.234' E, 312–525 m, SJADES 2018 stn CP33, 29 March 2018; ZRC 2020.0036 , 1 female (cl 26.4 mm, pcl 14.7 mm, cw 10.3 mm; with rhizocephalan), E of Tinjil Island, Indian Ocean , 6°57.221–56.664'S 105°54.754–55.315'E, 517–727 m, SJADES 2018 stn CP26, 28 March 2018; ZRC 2020.0037 , 1 male (cl 21.1 mm, pcl 12.0 mm, cw 10.4 mm; with epicaridean), 1 female (pcl 11.2 mm,cw 7.2 mm), S of Tanjong Gedeh, Java, Indian Ocean, 7°51.120–51.718'S 107°46.245–46.375'E, 637–689 m, SJADES 2018 stn CP48, 1April 2018; ZRC 2020.0038 , 5 males (cl 34.7, pcl 20.3 mm, cw 14.6 mm; cl 27.2 mm, pcl 17.0 mm, cw 11.6 mm; cl 25.6 mm, pcl 15.2 mm, cw 10.6 mm; cl 25.1 mm, pcl 15.8 mm, cw 10.8 mm; cl 22.6 mm, pcl 14.5 mm, cw 10.3 mm), 1 damaged male, 9 females (cl 26.7 mm, pcl 17.3 mm, cw 12.3 mm; cl 25.3 mm, pcl 17.4 mm, cw 12.2 mm; cl 22.5 mm, pcl 14.4 mm, cw 10.3 mm; cl 14.5 mm, pcl 9.0 mm, cw 6.5 mm; pcl 8.9 mm, cw 5.4 mm), 3 females (cl 21.7 mm, pcl 15.0 mm, cw 13.3 mm; cl 23.2 mm, pcl 14.1 mm, cw 12.4 mm; cl 17.4 mm, pcl 11.4 mm, cw 9.7 mm; with epicaridean), 2 ovigerous females (cl 24.0 mm, pcl 16.5 mm, cw 11.6 mm; pcl 14.6 mm, cw 10.2 mm), S of Cilacap, Indian Ocean , 8°15.885–16.060'S 109°10.163–10.944'E, 528–637 m, SJADES 2018 stn CP39, 30 March 2018. Seychelles: USNM 41400 , 1 male (pcl 18.1 mm, pcl 12.6 mm, cw 8.0 mm), 4°35'S 55°40'E, 62 m, Sealark expedition stn F7, RV Sealark, 20 October 1905. Saya de Mahla Bank: USNM 41399 , 1 female (cl 27.5 mm, pcl 18.2 mm, cw 12.9 mm), 10°30'S 61°30'E, 229 m, Sealark expedition stn C5, RV Sealark, 4 September 1905. Madagascar: MNHN-IU-2016-6897 , 1 juvenile female (cl 9.4 mm, pcl 6.8 mm, cw 4.4 mm), 12°22'S 46°25'E, 346–349 m, BIOMAGLO stn DW4788, 22 January 2017; ZRC 2011.1048 , 1 male (pcl 13.5 mm, cw 9.2 mm), 1 ovigerous female (cl 23.3 mm, pcl 15.3 mm, cw 10.7 mm), 12°46'S 48°12'E, 355–380 m, MIRIKY 2009 stn CP3224, 2 July 2009; MNHN-IU-2016-9321 , 1 juvenile male (cl 5.6 mm, pcl 4.0 mm, cw 2.4 mm), 12°58'S 45°15'E, 687–712 m, BIOMAGLO stn DW4866, 7 February 2017; MNHN IU-2011-5997 , 1 ovigerous female (cl 23.9 mm, pcl 15.8 mm, cw 10.5 mm), 12°59'21.588''S 48°06'05.4''E, 495–509 m, MIRIKY 2009 stn DW3176, 25 June 2009. Comores: MNHN, 1 female (cl 26.5 mm, pcl 15.9 mm, cw 10.9 mm),W of Great Western Pass, Mayotte , 12°46'S 44°58'E, 475–510 m, BENTHEDI BENT-61F, 29 Mar 1977. Mozambique Channel: MNHN-IU-2011-5989 , 3 males (pcl 15.1 mm, cw 10.2 mm to pcl 24.3 mm, cw 15.7 mm), 2 ovigerous females (pcl 14.9 mm, cw 10.7 mm; pcl 28.3 mm, cw 16.2 mm), 19°34.98'S 36°47.71'E, 636 m, MAINBAZA stn CC3154, 13 April 2009; ZRC 2011.1050 , 2 males (cl +22.0 mm, pcl 14.8 mm, cw 10.0 mm, cl 19.8 mm, pcl 13.4 mm, cw 8.9 mm), 2 ovigerous females (pcl 18.1 mm, cw 12.1 mm; pcl 15.4 mm, cw 10.3 mm), 19°36'S 36°47'E, 636 m, MAINBAZA 2009 stn CC3154, 13April 2009; MNHN-IU-2017-8772 , 1 juvenile female (cl 9.2 mm, pcl 6.5 mm, cw 4.3 mm), 23°59'S 35°39'E, 206–210 m, MAINBAZA stn CC3160, 15April 2009.

Diagnosis. Carapace with at least 20 slender, sharp, upright dorsal spines (paired preorbital; paired hepatic; 6 gastric; 1 median cardiac; 1 median intestinal; on each side, 4 pairs branchial); hepatic spine ovate to circular in cross-section, lateral surface rounded. G1 distal margin oblique, straight to irregularly gently sinuous.

Description (specimens> 10 mm pcl). Carapace pyriform, pcl 1.4–1.6× width, regions weakly defined, entire surface with tomentum of short lobular setae. Pseudorostral spines usually strongly divergent for entire length (occasionally weakly divergent), straight to outwardly curved (in dorsal view), straight to curved but slightly upcurved in lateral view; length 0.4–0.8 × pcl; margins lined with short, soft, lobular setae and scattered simple setae. Dorsal orbital eave weakly expanded, produced as a long, slender upright spine, inclined anteriorly and usually slightly incurved; postorbital lobe short, anteriorly cupped; hiatus wide, U-shaped. Dorsal surface with long, slender, upright spines in following pattern: straight, near vertical hepatic spine, ovate to circular in cross-section, with lateral surface rounded; gastric region with 6 slender upright spines (2 in midline; paired epigastric and protogastric spines) and usually with two shorter spines or tubercles in transverse row between anterior and posterior median spines; cardiac and intestinal regions each with straight, upright spine; branchial regions each with 4 straight, upright, spines, 2 near lateral carapace margin and directed laterodorsally, 2 on upper surface, almost vertical. Pterygostomian region with 3 or 4 tubercles in longitudinal row below moult suture, followed by tubercle on anterior branchial submargin slightly below moult suture.

Eyestalks short, sparsely setose anteriorly, cornea terminal. Basal antennal article length about twice width; surface shallowly sulcate longitudinally; anterolateral angle blunt, weakly produced to small spine, visible in dorsal view; lateral margin lateral margin concave, not expanded under eyestalk; prominent tubercle situated between antennal gland and margin of ventral orbital hiatus.

Maxilliped 3 unarmed, merus subtriangular, anterolateral angle weakly produced, apex rounded, slightly wider than ischium; ischium subquadrate, outer surface with shallow longitudinal depression.

Cheliped (pereopod 1) length 1.1–2.0 (usually> 1.4) × pcl (male), 0.7–1.3 × pcl (female); merus slightly shorter than propodus, extensor margin with proximal tubercle and small distal spine, flexor margin with 2 or 3 low, widely spaced tubercles; carpus shorter than dactylus, unarmed, although large adult males with dorsal and mesial ridge; propodus smooth, laterally compressed, dorsally cristate and more robust in adult males, palm length 2.0–3.1 (usually> 2.4)× height (male), 2.2–3.3 (usually> 2.6)× height (female); dactylus and pollex equal, length 0.6–0.9× palm length (male), 0.7–0.9× palm length (female); occlusal margins crenulate, proximal gape slight in males, absent in females.

Ambulatory legs (P2–5) slender, subcylindrical in cross-section, sparsely covered with short simple setae and short, club-like setae; merus extensor margin with short distal spine, sometimes indistinct on P5; dactyli unarmed, covered with short setae, apex corneous. Pereopod 2 length 2.0–3.4 × pcl (usually> 2.6) (male), 1.9–2.6 (usually <2.4) × pcl (female); merus 0.8–1.3 (usually ≥ 1.0) (male), 0.7–1.0 (usually <0.9) (female). Pereopod 5 length 1.4–1.9 (usually> 1.6) × pcl (male), 0.9–1.6 (usually <1.5) × pcl (female); merus 0.5–0.7 (usually 0.6) × pcl (male), 0.4–0.6 (usually <0.5) × pcl (female).

Pleon with 6 free somites and telson, unarmed; widest at somites 2 and 3 in males, at somites 5 and 6 in females; surface covered with short bulbous setae. Male telson triangular, as long as wide, margins straight, apex rounded.

G1 straight, flattened; distally expanded, distolaterally produced to acute triangular point, distomesially bluntly approximately right-angled; distal margin oblique, straight to irregularly gently sinuous. G2 simple, about ¼ length of G1; endopod absent.

Colour in life. Carapace off-white to whitish-orange dorsally, anterior margins and rostral spines orange or pink; chelipeds and ambulatory legs pink. ( Fig. 5C, D ).

Remarks. Comparison of specimens from across the wide putative range of S. pulchra , including the Investigator specimen from the Andaman Sea, shows that specimens from the Western Indian Ocean to the Andaman Sea and southwestern Indonesia are not referable to S. pulchra sensu stricto, but to S. livermorii , according with recognition of both species as separate by Richer de Forges et al. (2021) in anticipation of present results. Other eastern Indian Ocean records attributed to S. pulchra (i.e., Australia and southeastern Indonesia) are based on S. jimlowryi sp. nov., described herein.

Samadinia livermorii was described based on a male and two females from the Andaman Sea between North Sentinel Island and South Sentinel Island (RIMSS Investigator stn 56, 220–240 fms) and has long been considered a synonym of S. pulchra . Unfortunately, the fate of the type material of S. livermorii is currently not known: the specimens ought to be in the Zoological Survey of India, Calcutta, but they could not be found despite extensive searches (S. Mitra, pers com.). Neither are they in the collections of the Natural History Museum (London), Smithsonian Institution (Washington DC) nor the Australian Museum (Sydney), where many specimens from the Investigator expeditions are now deposited. Thus, the type material of S. livermorii appears to be lost. Nevertheless, a non-type specimen of S. livermorii from the Andaman Sea collected by the Investigator (female, pcl 12.3 mm, NHM 1896.5.14.7) anchors our identification of the western Indonesian and western Indian Ocean specimens as S. livermorii .

Among the three species of the S. pulchra complex, S. livermorii morphologically resembles S. pulchra in the straight or slightly uneven distal margin of the adult G1 ( Fig. 7A, B, I, J ) (versus bilobate in S. jimlowryi ; Fig. 7C, H ) and in having typically straight, upright dorsal carapace spines ( Fig. 6C, F ) (versus anteriorly curved spines in S. jimlowryi ; Fig. 4A–C, F, H ). Samadinia livermorii differs from both S. jimlowryi and S. pulchra in having a rounded rather than flattened outer surface of the hepatic spine ( Fig. 6C, F versus Fig. 2D , 4C ). The length of the carapace spines is subject to allometry and individual variation, but the longest carapace spine in adult S. livermorii and S. pulchra is 0.2 × pcl, compared to 0.5 × pcl in S. jimlowryi .

Specimens of S. livermorii examined are similar throughout the range, although females from the eastern Indian Ocean might mature at a smaller size than those from the west. Eastern specimens are mature by pcl 12–13 mm, with the smallest ovigerous female at pcl 12.3 mm (NHM 1896.5.14.7) compared to pcl 14.9 mm (ZRC 2011.1050) for western Indian Ocean specimens. In other respects, the eastern and western Indian Ocean specimens agree well and so are considered conspecific. Despite the good collections of S. livermorii from the western and eastern Indian Ocean, none are yet known from intermediate localities, almost certainly an artefact of limited sampling at outer shelf and slope depths in the Indian region. Only in recent years have efforts to document the Indian deep-water crustacean fauna accelerated (e.g., Ahyong & Kumar, 2018; Devi et al., 2019; Ng et al., 2019; Macpherson et al., 2020; Padate et al., 2020, 2021, 2022), so it is likely that S. livermorii will eventually be found there. All known specimens of S. livermorii are from Indian Ocean localities.

Distribution. East Africa to the Andaman Sea and southwestern Indonesia ( Fig. 1 ); 62–1027 m (usually 400–500 m).

ACKNOWLEDGEMENTS. The authors would like to thank many colleagues and friends who have helped make important specimens available for this study: Joanne Taylor (NMV); Laure Corbari, Paula Martin-Lefèvre, and Sébastien Soubzmaigne (MNHN); Paul Clark (NHM); Jose Christopher Mendoza and Muhammad Dzaki Bin Safaruan (ZRC); Karen Reed, Courtney Wickel, and Rafael Lemaitre (USMN); Bianca Trautwein and the late Professor Michael Türkay (SMF); and Hironori Komatsu (NSMT). We also thank Rafael Lemaitre and Karen Reed, for their hospitality in Washington DC, and the late Alain Crosnier for his hospitality in Paris. Tin-Yam Chan and Karen Gowlett-Holmes are gratefully acknowledged for the use of colour images in Fig. 3 . Gary Poore and Bertrand Richer de Forges are thanked for their constructive reviews. The SJADES cruise (chief scientists: Dwi Listyo Rahayu and Peter K. L. Ng), aboard RV Baruna Jaya VIII , was a joint Indonesian-Singapore expedition to southern Java funded by the National University of Singapore and the Research Center for Oceanography, Indonesian Institute of Sciences (LIPI) in commemoration of 50 years of bilateral cooperation (RISING50) between the two countries. We also thank Tin-Yam Chan and his team for their invaluable help in the trawling work and other support, and to Chien-Hui Yang for tirelessly repairing the damaged nets during the SJADES cruise. We are also very grateful to the Indonesian crew of Baruna Jaya VIII and especially Captain Jefri Juliansyah, for their hard work and fortitude. We are most grateful to geologist Praditya Avianto (LIPI) for his invaluable help with the geography of the seabed.

Figures

Figure 1. Distribution of species of the Samadinia pulchra complex: S. pulchra (Miers in Tizard, Moseley, Buchanan & Murray, 1885) (▲), S. jimlowryi sp. nov. (●), S. livermorii (Wood-Mason in Wood-Mason & Alcock, 1891) (■).

Figure 3. Samadinia pulchra (Miers in Tizard, Moseley, Buchanan & Murray, 1885). (A) male (pcl 12.5 mm, cw 7.5 mm), Philippines, CP2659, ZRC 2011.1053; (B) male (pcl 19.5 mm, cw 12.9 mm), Philippines, CP2384, NMCR; (C) male (pcl 21.4 mm, cw 14.5 mm), Macclesfield Bank, CP4155, ZRC. Image credits: Tin-Yam Chan.

Figure 4. Samadinia jimlowryi sp. nov. A–E, male holotype (pcl 32.7 mm, cw 22.3 mm), northwestern Australia, NMV J75811; F–H, spent female paratype (pcl 23.7 mm, cw 15.4 mm), northwestern Australia, NMV J58220. (A, F) dorsal habitus; (B, H) carapace, dorsal view; (C) carapace, right lateral view; (D) right chela; (E, G) ventral cephalothorax and pleon.

Figure 5. Samadinia jimlowryi sp. nov., female paratype (pcl 23.7 mm, cw 15.4 mm), Western Australia, SS05/2007/107, NMV J55947: (A) dorsal habitus; (B) carapace, left lateral view.Samadinia livermorii (Wood-Mason in Wood-Mason &Alcock, 1891):(C) male (pcl 14.8 mm, cw 10.0 mm), Mozambique, CC3154, ZRC 2011.1050; (D) ovigerous female (pcl 15.8 mm, cw 10.5 mm), Madagascar, DW3176, MNHN IU-2011-5997. Image credits: Karen Gowlett-Holmes (A, B), Tin-Yam Chan (C, D).

Figure 6. Samadinia livermorii (Wood-Mason in Wood-Mason & Alcock, 1891): A–C, ovigerous female (cl 18.1 mm, pcl 12.3 mm, cw 8.0 mm), Andaman Sea, NHM 1896.5.14.7; D–F, male (pcl 13.5 mm, cw 9.2 mm), Madagascar, ZRC 2011.1048. (A) dorsal habitus; (B, E) ventral cephalothorax and pleon; (D) habitus; (C, F) carapace, right lateral view.

Figure 7. G1 (A–C, E–I) and G2 (D), left pleonal view. Samadinia pulchra (Miers in Tizard, Moseley, Buchanan & Murray, 1885): (A) holotype, pcl 19.3 mm, Philippines, NHM 1884.31; (B) male (pcl 17.3 mm, cw 11.6 mm), South China Sea, ZRC 1968.2.13.4. Samadinia jimlowryi sp. nov.: (C–D) male holotype (pcl 32.7 mm, cw 22.3 mm), NMV J58025; (E) male (pcl 15.9 mm, cw10.1 mm), Bali, AM P.34657; (F–H) male (pcl 12.3 mm, cw 7.9 mm), male (pcl 20.6 mm, cw 13.6 mm), male (pcl 38.5 mm, cw 26.3 mm), MNHN B29100. Samadinia livermorii(Wood-Mason in Wood-Mason &Alcock, 1891): (I) male (pcl 15.1 mm,cw 10.2 mm), Madagascar, MNHN IU-2011- 5989; (J) male (pcl 20.3 mm, cw 14.6 mm), Indonesia, ZRC 2020.0038. Scale bars:A, C, D, J = 2.0 mm; B, F–I = 1.0 mm, E = 0.5 mm.

Figure2.Samadinia pulchra(Miers in Tizard,Moseley, Buchanan& Murray,1885),holotype male (pcl 19.3mm,cw 13.0mm),Philippines, NHM 1884.31. (A) dorsal; habitus; (B) thoracic sternum and pleon; (C) ventral anterior cephalothorax; (D) carapace, right lateral view.