Samadinia jimlowryi, Ahyong & Lee & Ng, 2023

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 : 348-351

Samadinia jimlowryi sp. nov.

urn:lsid:zoobank.org:act:65D5DC08-D391-41A7-A573-ADC243151498

Figs 1 , 4 , 5A, B , 7C–H

Rochinia pulchra .— Griffin & Tranter, 1986a: 185, 186.— Griffin & Tranter, 1986b: 363.— Richer de Forges & Poore, 2008: 68 , 69, fig. 2b [not Amathia (Amathia) pulchra Miers in Tizard, Moseley, Buchanan & Murray, 1885].

Holotype: NMV J58025 , male (cl 65.6 mm, pcl 32.7 mm, cw 22.3 mm), Kulumburu L29 transect, NW Australia, 13°15.90–16.35'S 123°22.45–21.40'E, 394– 390 m, beam trawl, SS05/2007/180, RV Southern Surveyor, coll. D. Bray, 7 July 2007. Paratypes: NMV J75811 , 1 female (cl 55.1 mm, pcl 28.7 mm, cw 20.2 mm), collected with holotype; NMV J58172 , 1 juvenile female (cl 29.9 mm, pcl 16.8 mm, cw 10.8 mm), Ashmore L30 transect, NW Australia, 12°31.766–30.833'S 123°25.633–25.367'E, 401–404 m, beam trawl, SS05/2007/192, RV Southern Surveyor , coll. D. Bray, 7–8 July 2007; NMV J55681 , 1 immature male (pcl 11.8 mm, cw 8.0 mm), Lacepede L26 transect, NW Australia, 15°47.72–48.50'S 121°03.50–02.88'E, 119– 111 m, beam trawl, SS05/2007/129, RV Southern Surveyor, coll. D. Bray, 1 July 2007; NMV J55947 , 1 immature female (cl 43.9 mm, pcl 23.7 mm, cw 15.4 mm), Leveque L27 transect, NW Australia, 14°49.03–48.53'S 121°27.55–29.57'E, 407– 392 m, beam trawl, SS05/2007/107, RV Southern Surveyor, coll. D. Bray, 27 June 2007; NMV J558220 , 1 spent female (cl 43.9 mm, pcl 23.7 mm, cw 15.4 mm), Leveque L27 transect, NW Australia, 14°51.20–50.72'S 121°25.88–27.02'E, 403– 396 m, beam trawl, SS05/2007/144, RV Southern Surveyor, coll. D. Bray, 3 July 2007; AM P.35501 , 1 ovigerous female (cl 41.9 mm, pcl 24.3 mm, cw 16.4 mm), North West Shelf, 240 km NW of Port Hedland, 18°06'S 117°45'E, 500 m, trawl, S02/82/31, RV Soela, coll. J. Paxton, 7 April 1982.

Other material examined. Indonesia: MNHN B29063 , 5 males (cl 16.1 mm, pcl 10.3 mm, cw 6.6 mm to cl 46.6 mm, pcl 27.5 mm, cw 18.4 mm), 3 females (cl 37.8 mm, pcl 22.1 mm, cw 15.0 mm to cl 49.3 mm, pcl 29.1 mm, cw 21.0 mm), Kai, 5°17'S 132°50'E, 315–349 m,KARUBAR stn CP16, 24 October 1991; MNHN B29064 , 4 females (cl 35.3 mm, pcl 22.4 mm, cw 14.7 mm to cl 59.6 mm, pcl 32.1 mm, cw 23.0 mm), Kai , 5°21'S 132°30'E, 329–389 m, KARUBAR stn CC10, 23 October 1991; MNHN B29100 , 4 males (cl 19.8 mm, pcl 12.3 mm, cw 7.9 mm to cl 71.6 mm, pcl 38.5 mm, cw 26.3 mm), 1 female (cl 59.0 mm, pcl 32.2 mm, cw 21.7 mm), 1 juvenile female (cl 38.9 mm, pcl 22.7 mm, cw 14.6 mm), Kai , 5°23'S 132°29'E, 368–389 m, KARUBAR stn CP09, 23 October 1991; MNHN B29099 , 2 females (cl 19.2 mm, pcl 13.4 mm, cw 8.1 mm; cl 23.5 mm, pcl 13.8 mm, cw 8.9 mm), Kai , 5°23'S 132°37'E, 413–436 m, KARUBAR stn CP12, 23 October 1991; MNHN B29096 , 1 female (cl 19.7 mm, pcl 11.5 mm, cw 7.5 mm), Kai , 5°30'S 132°52'E, 336–346 m, KARUBAR stn CP25, 26 October 1991; MNHN B29093 , 1 male (cl 31.3 mm, pcl 19.4 mm, cw 12.4 mm), 2 juvenile females (pcl 12.8 mm, cw 8.3 mm; pcl 18.7 mm, cw 11.4 mm), Kai , 5°49'S 132°18'E, 296–299 m, KARUBAR stn CP05, 22 October 1991; MNHN B29095, 1 male (pcl 13.0 mm, cw 8.5 mm), Kai, 6°07'S 132°42'E, 241–363 m, KARUBAR stn CP37, 27 October 1991; MNHN B29061 , 2 males (cl 23.7 mm, pcl 15.0 mm, cw 9.5 mm; pcl 17.2, cw 10.6 mm), 1 spent female (cl 58.0 mm, pcl 29.7 mm, cw 20.6 mm), 4 juvenile females (cl 15.4 mm, pcl 9.7 mm, cw 6.1 mm to cl 26.2 mm, pcl 16.1 mm, cw 10.5 mm), Kai , 6°08'S 132°45'E, 390–502 m, KARUBAR stn CP35, 27 October 1991; AM P.34657 , 1 male (cl 25.3 mm, pcl 15.9 mm, cw 10.1 mm), off Boeleleng, Bali, 7°29'S 114°49'E, ca. 240 m, trawl, Th. Mortensen Java–South Africa Expedition stn 15n, 10 April 1929; MNHN B29098 , 1 female (cl 26.7 mm, pcl 15.5 mm, cw 9.7 mm), Tanimbar, 7°54'S 132°47'E, 302–305 m, KARUBAR stn CP45, 29 October 1991; MNHN B29092 , 2 males (cl 20.9 mm, pcl 12.9 mm, cw 7.7 mm; cl 19.3 mm, pcl 12.6 mm, cw 7.7 mm), 1 female (cl 29.1 mm, pcl 17.1 mm,cw 10.8 mm), Tanimbar , 8°20'S 132°11'E, 399–405 m, KARUBAR stn CP59, 31 October 1991; MNHN B29097 , 2 females (cl 17.3 mm, pcl 10.6 mm, cw 6.8 mm; cl 27.4 mm, pcl 16.1 mm, cw 10.4 mm), Tanimbar , 8°38'S 131°44'E, 477–480 m, KARUBAR stn CP71, 2 November 1991; MNHN B29094 , 3 females (cl 18.1 mm, pcl 10.8 mm, cw 6.7 mm to cl 30.5 mm, pcl 17.3 mm, cw 11.1 mm), Tanimbar , 8°41'S 131°47'E, 410–413 m, KARUBAR stn CP70, 2 November 1991; MNHN B29119 , 2 males (cl 57.0 mm, pcl 33.7 mm, cw 24.3 mm; cl 71.2 mm, pcl 36.8 mm, cw 25.6 mm), 7 ovigerous females (cl 46.0 mm, pcl 26.8 mm, cw 18.2 mm to cl 64.0 mm, pcl 33.5 mm, cw 24.0 mm), 1 juvenile female (cl 30.4 mm, pcl 17.5 mm, cw 12.1 mm), Tanimbar , 8°42'S 131°53'E, 356–368 m, KARUBAR stn CP69, 2 November 1991; MNHN B29062 , 1 male (cl 50.9 mm, pcl 27.5 mm, cw 18.8 mm), Tanimbar , 8°57'S 131°27'E, 352– 346 m, KARUBAR stn CP77, 3 November 1991.

Diagnosis. Carapace with at least 20 sharp, slender, anteriorly curved dorsal spines (paired preorbital; paired hepatic; 6 gastric; 1 median cardiac; 1 median intestinal; on each side, 4 pairs branchial); hepatic spine with lateral surface flattened or weakly sulcate. G1 distal margin oblique, with short rounded projection adjacent to distomesial projection.

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 to subparallel), straight to outwardly curved (in dorsal view), straight but slightly upcurved in lateral view; length 0.6–1.0 × 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 with lateral surface flattened or weakly sulcate; gastric region with 6 slender upright spines: 2 in midline (anteriormost longest, 0.5 × pcl in holotype), paired epigastric and protogastric spines, and usually with 2 shorter spines or tubercles in transverse row between anterior and posterior median spines; cardiac and intestinal regions each with spine, usually slightly curved anteriorly; branchial regions each with 4 spines, apices slightly curved anteriorly, 2 near lateral carapace margin and directed laterodorsally, 2 on upper surface, almost vertical. Pterygostomial 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, not 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 1.2–1.9 × pcl (usually> 1.4) (male), 1.2–1.4 × pcl (usually <1.4) (female); merus slightly shorter than propodus, extensor margin with 1 or 2 small proximal spines or acute tubercles and small but distinct distal spine; 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 2.4–3.2× height (male), 3.1–3.5× height (female); dactylus and pollex equal, length 0.7–0.8× palm length (male), 0.8× 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 2.6–3.1 × pcl (male), 2.5–2.7 × pcl (female); merus 1.0–1.2 × pcl (male), 1.0–1.1 (usually 1.0) (female). Pereopod 5 length 1.5–1.8 (usually> 1.7) × pcl (male), 1.6–1.8 × pcl (usually 1.6) (female); merus 0.5–0.6 in both sexes.

Pleon with 6 free somites and telson; widest at somites 2 and 3 in males, at somites 5 and 6 in females; surface covered with short bulbous setae; somites 1 and 2 with short stout median spine; somite 3 with median tubercle. Male telson triangular, slightly longer than wide, margins straight, apex rounded.

G1 straight, flattened; distally expanded, distolaterally produced to acute triangular point, distomesially a short, rounded to bluntly angular projection; distal margin oblique, with short rounded projection adjacent to distomesial projection. G2 simple, about ¼ length of G1; endopod absent.

Colour in life. Carapace and pereopods overall creamy-white. Rostral spines and anterior carapace spines dull orange; dorsal carapace spines with dull orange subdistal band. Cheliped fingers pinkish. ( Fig. 5A, B ).

Etymology. Named in honour of our late colleague and friend, Jim Lowry, for his substantial contributions to carcinology.

Remarks. Samadinia jimlowryi sp. nov. is separable from both S. pulchra and S. livermorii by the form of the G1. In S. jimlowryi , the G1 apex has a narrow and blunt but prominent lobe on the anteromesial angle resulting in a prominently uneven distal margin ( Fig. 7C, E–H ), compared to the essentially straight or more evenly irregular margin in S. pulchra and S. livermorii ( Fig. 7A, B, I, J ). The new species further differs from both S. pulchra and S. livermorii in the curvature of the dorsal and lateral carapace spines. In S. jimlowryi the carapace spines tend to be anteriorly curved ( Fig. 4A–C, F, H ) (versus directed essentially vertically; Figs 1A, D , 2 , 5C, D , 6A, C, D, F ) being most evident in specimens above about 20 mm pcl and becoming more pronounced with increasing body size. Samadinia jimlowryi is similar to S. pulchra and further differs from S. livermorii in the flattened (versus rounded) lateral surface of the hepatic spine.

The length of the dorsal carapace spines in S. jimlowryi varies allometrically, with smallest specimens having proportionally shorter spines. The rostral spines distinctly diverge, are occasionally subparallel, and vary in length from two-thirds to as long as postrostral carapace length ( Fig. 4A, B, F, H ). The rostral spines in dorsal view are straight or curved outwards, and in lateral view, generally appear straight and slightly inclined dorsally. Several specimens are encrusted with sponge and barnacles.

Samadinia jimlowryi apparently matures at a larger size than either S. pulchra or S. livermorii , which are ovigerous by pcl 15 mm or less. Females of S. jimlowryi show a rather abrupt change in pleonal size and shape at 23–24 mm pcl, at which size they are mature. The male gonopods reach full length by ca. 12 mm pcl, although the final form of the oblique margin of the tip (with the acutely angular tip and two blunt lobes) is not evident until about 16–20 mm pcl ( Fig. 7C, E–H ). Marked inflation of the chelipeds is not evident until ca. 25 mm pcl. A pair of processes in transverse row (rarely on one side only) is usually present between the anterior two median gastric spines. These processes range from a low blunt tubercle in the smallest specimens (usually concealed by the surface tomentum), to a sharp spine two-thirds the height of the median gastric spines in some of the largest specimens.

Previous records of S. pulchra from southern Indonesia and northwestern Australia ( Griffin & Tranter, 1986a, b; Richer de Forges & Poore, 2008) have been re-assessed and are referrable to S. jimlowryi . Samadinia pulchra sensu stricto is not known from Australian or Indonesian waters.

Distribution. Timor and Arafura seas, from southeastern Indonesia to northwestern Australia ( Fig. 1 ); 240– 502 m.

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 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.