Tenagopelta pacifica, Ng, Peter K. L. & Castro, Peter, 2016

Ng, Peter K. L. & Castro, Peter, 2016, Revision of the family Chasmocarcinidae Serène, 1964 (Crustacea, Brachyura, Goneplacoidea), Zootaxa 4209 (1), pp. 1-182 : 79-82

Tenagopelta pacifica n. sp.

( Figs. 17 A, B; 26F; 33G; 42I; 47A, B; 54F; 61E; 79A‒E; 88C; 91G; 102)

Hephthopelta sp.— Serène & Vadon 1981: 118, 119, 120, 123 [ Philippines] Hephthopelta cf. lugubris — Komai et al. 2012: 149, fig. 7 [ Philippines].

Type material. Holotype male (11.0 × 12.8 mm) ( NMCR) [photographed], Philippines, Bohol Sea, Maribojoc Bay , 100‒300 m, P.K.L. Ng coll., 11.2003‒04.2004.

Paratypes: 1 male (10.7 × 11.2 mm) (USNM 46387), 1 female (10.7 × 11.7 mm) (USNM 46386); 1 female (7.6 × 8.0 mm) ( USNM 46385 ), Philippines, South China Sea , near Luzon, Albatross, stn 5278.—PANGLAO 2004 : 1 female (ZRC 2015.218), Philippines, Balicasag I., P.K.L. Ng coll., 29.05.2004; 1 male (10.2 × 11.4 mm) ( ZRC 2015.212 ) [G1 drawn], Maribojoc Bay , 100‒300 m, P.K.L. Ng coll., 11.2003‒04.2004 ; 2 males, 2 females ( ZRC 2015.213 ), Maribojoc Bay , 100‒300 m, P.K.L. Ng coll., 11.2003‒04.2004.—PANGLAO 2005 : 1 female ( ZRC 2015.202 ), Philippines, Bohol / Sulu Sea, stn CP2363, 09°06.0’N, 123°25.0’E, 437–439 m, 26.05.2005 ; 1 female ( ZRC 2015.201 ), Bohol Sea, off Balicasag I., stn CP2394, 09°29’N, 123°40'E, 470–566 m, 30.05.2005 ; 1 female (8.2 × 9.3 mm) ( ZRC 2015.197 ), Bohol Sea, Maribojoc Bay , stn CP2395, 09°36.2’N, 123°43.8’E, 382–434 m, 31.05.2005 ; 1 female (9.2 × 10.4 mm) ( ZRC 2015.187 ) [photographed], Bohol Sea, Maribojoc Bay , stn CP2397, 09°35’N, 123°42'E, 642–669 m, 31.05.2005 ; 2 juveniles, 6 males, 9 females ( ZRC 2015.190 ), Bohol Sea, Maribojoc Bay , stn CP2407, 09°41’N, 123°48'E, 256–268 m, 01.06.2005 ; 1 male, 1 ovigerous females, 2 females (QM, ex ZRC), Bohol Sea, Maribojoc Bay , stn CP2408, 09°43.5’N, 123°47.1’E, 121–137 m, 01.06.2005 ; 1 male ( ZRC 2015.199 ), Bohol Sea, Maribojoc Bay , stn CP2409, 09°44.8’N, 123°44.8’E, 220–257 m, 01.06.2005 ; 1 female (6.6 × 6.9 mm) ( ZRC 2015.200 ) [photographed], Bohol I., Cortes , stn T15, 09°41.2’N, 123°49.0’E, 180 m, 24.06.2004. — AURORA 2007: 1 female (6.3 × 6.8 mm) (MNHN-IU-2014-12808 ZRC 2015.208 ) [photographed], northwestern Philippines, stn CP2656, 16°02.01’N –16°01.7’N to 121°52.02’E–121°53.9’E, 262‒278 m, 20.05.2007; 1 juvenile (ZRC 2015.207), stn CP2666, 15°56.35’N–15°57.65’N to 121°43.67’E–121°45.31’E, 184‒199 m, 02.05.2007; 1 female (8.2 × 9.4 mm) (MNHN-IU-2014-12809, ex ZRC 2015.203), stn CP2667, 15°56.81’N–15°54.52’N, 121°46.97’E–121°46.44’E, 280‒292 m, 292 m, 21.05.2007; 1 male (10.5 × 11.8 mm), 1 female (8.4 × 9.3 mm) [photographed] (ZRC 2015.193), stn CP2717, 14°29.96’N–14°28.94’N to 121°41.67’E– 121°43.13’E, 311‒362 m, 29.05.2007; 9 males, 3 females, 3 ovigerous females (ZRC 2015.194), stn CP2717, 15°04.36’N–15°04.06’N to 121°42.75’E–121°41.06’E, 368‒484 m, 29.05.2007; 2 males (8.0 × 9.0 mm, 8.0 × 9.1 mm), 1 female (7.2 × 7.9 mm) (ZRC 2015.192), stn CP2715, 14°31.50’N–14°33.09’N to 121°42.14’E– 121°42.05’E, 244‒249 m, 29.05.2007; 2 males, 2 females (10.0 × 11.4 mm) [photographed] (ZRC 2015.219), stn CP2716, 14°32.14’N–14°30.41’N to 121°40.80’E–121°41.16’E, 298‒356 m, 29.05.2002; 2 females (ZRC 2015.204), stn CP2718, 14°29.93’N–16°28.63’N to 121°46.72’E–121°97.56’E, 200‒220 m, 29.05.2007; 3 males (MNHN-IU-2014-12810, ex ZRC 2015.206), stn CP2719, 14°27.84’N–14°26.47’N to 121°47.90’E–121°48.36’E, 155‒204 m, 29.05.2007; 6 males, 7 females (ZRC 2015.195), stn CP2720, 14°25.30’N–14°26.63’N to 121°47.70’E—121°46.68’E, 256‒301 m, 29.05.2007; 5 males, 9 females (ZRC 2015.191), stn CP2721, 14°24.03’N–14°26.26’N to 121°46.83’E—121°47.56’E, 340‒360 m, 29.05.2007; 3 males, 2 females, 2 ovigerous females (MNHN-IU-2014-12811, ex ZRC 2015.196), stn CP2722, 14°24.45’N–14°25.80’N to 121°47.90’E— 121°46.19’E, 291‒338 m, 29.05.2007; 1 female (ZRC 2015.205), stn CP2734, 15°56.41’N–15°56.98’N to 121°48.71’E–121°49.21’E, 453‒460 m, 01.06.2007; 1 male (ZRC 2015.188), stn CC2746, 15°58.78’N– 15°56.63’N to 121°46.44’E–121°44.85’E, 182‒220 m, 0 2.06.2007.

Other material examined. Philippines. Hakuho-maru : 1 female (CBM-ZC 8770), Sulu Sea, stn SA-2, 10°36.48’N, 121°31.56'E, 362‒372 m, S. Ohtsuka coll., 08.12.2002 .—MUSORSTOM 1: 4 males, 3 females (MNHN-IU-2013-15775, ex MNHN B-10501), stn CP25, 14°02’N, 120°18’E, 191‒200 m, 22.03.1976.— MUSORSTOM 2: 2 males (MNHN-IU-2013-9054), stn CP21, 14°02’N, 120°17’E, 191‒192 m, 22.11.1980; 1 male, 1 female (MNHN-IU-2013-9055), stn CP69, 14°07’N, 120°03’E, 1800‒1950 m, 30.11.1980.— MUSORSTOM 3: 2 males, 2 females (MNHN-IU-2013-9052), 1 ovigerous female, stn CP99, 14°01’N, 120°18’E, 196‒204 m, 01.06.1985.— PANGLAO 2005: 2 young females (smaller 6.9 × 7.7 mm) ( ZRC 2015.198 ) [photographed], Bohol Sea, Maribojoc Bay , stn CP2332, 09°39’N, 123°46'E, 396–418 m, 22.05.2005 ; 2 males, 1 female (all badly damaged) ( ZRC 2015.189 ) [photographed], Bohol Sea, off Pamilacan I., stn CP2348, 09°30’N, 123°52'E, 196–216 m, 24.05.2005 ;

Indonesia. 2 males (larger 12.2 × 14.3 mm), 3 females (largest 10.7 × 13.1 mm) (MNHN-IU-2013-9053), CORINDON 1, Makassar Strait, stn 273, 01°56.0’S, 119°16.0’E, 220‒ 180 m, 0 7.11.1980.

Diagnosis. Carapace ( Figs. 17 A, B; 102) subtrapezoidal, globose, 1.0–1.2 wider than long, margins with short setae; front bilobed, with shallow median cleft; anterolateral margins arcuate, without distinct lobes or teeth. Posterior margin of epistome ( Fig. 26 F) with broad semicircular median lobe with deep median fissure, semicircular lateral margins. Eye peduncle ( Fig. 26 F) filling orbit, short, mobile; cornea reduced, pigmented. Third maxilliped ( Fig. 33 G) merus quadrate, ischium rectangular, about same length as merus. Chelipeds ( Figs. 17 A, B; 47A, B; 102) subequal in length, slightly dissimilar in females, heteromorphic in males; fingers of minor chela ( Fig. 47 B) subcircular in cross-section, not distinctly laterally flattened, gently tapering to tip, scissor-like, cutting margins with distinct sharp teeth; major chela of males ( Fig. 47 A) with enlarged dactylar teeth. Ventral surface of cheliped merus with 3 large, conspicuous teeth (sometimes additional small teeth or large tubercles) on outer margin in both sexes ( Fig. 42 I). Outer surface of adult male major chela with prominent swelling on median surface adjacent to dactylus ( Fig. 102 B). Inner margin of cheliped carpus with long distal tooth ( Fig. 17 A, B). Inner margin of basis-ischium of adult major cheliped gently granuliform ( Fig. 17 A). Long setae along margins of fingers, distal portion of cheliped propodi, dactyli, propodi of ambulatory legs. Proportionally long ambulatory legs ( Fig. 17 A, B). Meri of ambulatory legs with microscopic granules. P5 dactylus slightly upcurved ( Figs. 17 B; 102A, C, D, F); merus 0.8 cl. Fused thoracic sternites 1, 2 ( Fig. 54 F) semicircular, broad, short; fused thoracic sternites 3, 4 broad ( Figs. 54 F; 88C; 91G). Male pleon ( Figs. 54 F; 61E) with proportionally short telson. Sterno-pleonal cavity deep, press-button for pleonal holding as small, short tubercle posterior to thoracic sternal suture 4/5 near edge of sterno-pleonal cavity. Male thoracic sternite 8 short, rectangular; “supplementary plate” long, subovate; structures separated by relatively wide gap with most of the penis exposed (e.g., Fig. 61 E). G1 ( Fig. 79 A‒D) with stout basal part; distal two-thirds long, tapering, with short spinules; tip subtruncate. G2 ( Fig. 79 E) longer than G1, straight, distal segment slender, directed inwards. Somites of female pleon ( Fig. 88 C) with convex lateral margins; telson proportionally short. Sterno-pleonal cavity of female ( Fig. 91 G) deep. Vulvae widely separated on outer margins of cavity close to suture 5/6.

Colour. The carapace of adult specimens is white to light brown with white pereiopods in life ( Fig. 102 A‒C). Younger specimens have carapaces that vary from light brown to bright pink ( Fig. 102 D‒F), with smallest specimens possessing pink pereiopods as well ( Fig. 102 F).

Etymology. The epithet pacifica denotes the distribution of the new species in the Pacific Ocean in contrast to the Indian Ocean distribution of its two congeners.

Remarks. Specimens reported as “ Hephthopelta sp.” by Serène & Vadon (1981: 123) from the western Philippines are almost certainly Tenagopelta pacifica n. sp. as we have material from MUSORSTOM 1 and 2 that were referred to this species. The specimens on hand (including USNM specimens from Philippines identified by M.J. Rathbun) are remarkably consistent in all the diagnostic characters, with all of them possessing three welldeveloped, sharp teeth or pointed tubercles on the ventral, outer margins of the cheliped merus. The swelling on the median outer surface of the major chela adjacent to dactylus is most prominent in large males (e.g., Fig. 102 B), being less distinct but still discernible in smaller ones.

Tenagopelta pacifica n. sp. is close to T. potens (Davie & Richer de Forges, 2013) from Papua New Guinea, northeastern Australia and New Caledonia in its carapace form and proportions of the ambulatory legs. The most effective way to separate them is by their G1 structures; in T. pacifica n. sp., the distal two-thirds is elongated and relatively slender ( Fig. 79 A), whereas the distal half of the G1 is distinctly shorter and stouter ( Fig. 79 K–N) in T. potens .

The specimens from the Makassar Straits in Indonesia (MNHN-IU-2013-9053) are referred to T. pacifica at present as they best agree with this species. The G1 is slightly shorter but essentially similar and can easily be explained by variation. The swelling on the outer surface of the male major chela is relatively lower and less pronounced compared to similar sized specimens from Philippines but this may also be due to variation.

Distribution. Western Pacific Ocean ( Philippines, Indonesia). Depth: 100– 669 m.

Figures

FIGURE 17. Overall dorsal view of species of Tenagopelta n. gen. A, T. pacifica n. sp., Philippines: holotype male 10.3 × 11.9 mm (NMCR); B, T. pacifica n. sp., Philippines: female 9.2 × 10.4 mm (ZRC 2015.187); C, T. brachyphallus n. sp., Australia: holotype male 6.1 × 6.9 mm (NMV J 61680); D, T. brachyphallus n. sp., Australia: female 6.9 × 7.6 mm (NMV J 61680); E, T. potens, Papua New Guinea: male 10.3 × 12.1 mm (ZRC 2015.241); F, T. potens, Papua New Guinea: female 11.3 × 13.1 mm (ZRC 2015.241); G, T. potens, New Caledonia: female 7.4 × 8.5 mm (MNHN-IU- 2013 - 9469).

FIGURE 26. Frontal view of species of Statommatia n. gen. and Tenagopelta n. gen. A, Statommatia apta, Philippines: holotype 7.8 × 9.4 mm (USNM 46389); B, Statommatia apta, Philippines: male 5.9 × 7.1 mm (ZRC 2015.239); C, Statommatia malagasy n. sp., Madagascar: holotype male 9.9 × 12.4 mm (MNHN-IU- 2010 - 4370 a); D, Statommatia knudseni, New Caledonia: holotype male 4.7 × 6.9 mm (ZMUC CRU- 6974); E, Statommatia granulosa n. sp., New Caledonia: holotype male 4.1 × 4.7 mm (MNHN-IU- 2013 - 9454); F, Tenagopelta pacifica n. sp., Philippines: holotype male 10.3 × 11.9 mm (NMCR); G, Tenagopelta brachyphallus n. sp., Australia: holotype male 6.1 × 6.9 mm (NMV J 61680); H, Tenagopelta potens, Papua New Guinea: male 11.8 × 13.8 mm (MNHN-IU- 2011 - 1504).

FIGURE 33. Third maxilliped of species of Statommatia n. gen. and Tenagopelta n. gen. A, Statommatia apta, Philippines: holotype male 7.8 × 9.4 mm (USNM 46389); B, Statommatia apta, Philippines: male 5.9 × 7.1 mm (ZRC 2015.239); C, Statommatia knudseni, New Caledonia: holotype male 4.7 × 6.9 mm (ZMUC CRU- 6974); D, Statommatia pubescens, South China Sea: holotype male 5.0 × 7.9 mm (after Chen 1998: fig. 23 - 5); E, Statommatia malagasy n. sp., Madagascar: holotype male 9.9 × 12.4 mm (MNHN-IU- 2010 - 4370 a); F, Statommatia granulosa n. sp., New Caledonia: holotype male 4.1 × 4.7 mm (MNHN-IU- 2013 - 9454); G, Tenagopelta pacifica n. sp., Philippines: holotype male 10.3 × 11.9 mm (NMCR); H, Tenagopelta brachyphallus n. sp., Australia: holotype male 6.1 × 6.9 mm (NMV J 61680); I, Tenagopelta potens, Papua New Guinea: male 11.8 × 13.8 mm (MNHN-IU- 2011 - 1504).

FIGURE 42. P 4, P 5, and merus of cheliped of species of Angustopelta n. gen. A, A. robusta n. sp., Vanuatu: paratype male 12.3 × 13.3 mm (ZRC 2015.255); B, A. robusta n. sp., Vanuatu: paratype female 13.4 × 15.1 mm (MNHN-IU- 2010 - 5616); C, A. robusta n. sp., Vanuatu: paratype male 12.5 × 14.8 mm (MNHN-IU- 2013 - 9041); D, A. modesta n. sp., Solomon Islands: holotype male 13.3 × 15.1 mm (MNHU-IU- 2013 - 9038); E, A. modesta n. sp., Solomon Islands: paratype female 13.1 × 15.3 mm (ZRC 2015.258); F, A. aff. modesta n. sp., Papua New Guinea: female 9.3 × 9.9 mm (MNHN-IU- 2011 - 3307); G, Hephthopelta lugubris, Papua New Guinea: female 9.8 × 10.9 mm (MNHN-IU- 2011 - 2657), major cheliped; H, Angustopelta aurita, Philippines: female 10.9 × 12.7 mm (ZRC 2015.248), minor cheliped; I, Tenagopelta pacifica n. sp., Indonesia: male 11.0 × 12.4 mm (MNHU-IU- 2013 - 9053), minor cheliped; J, Chinommatia cavimanus, Philippines: male 9.7 × 11.5 mm (ZRC 2015.234), minor cheliped; K, Chinommatia cavimanus, Philippines: male 7.6 × 9.3 mm (ZRC 2015.231), minor cheliped; L, Notopelta mortenseni, Indonesia: holotype male 5.0 × 6.9 mm (ZMUC CRU- 7397), major cheliped; M, Statommatia apta, Philippines: males 8.5 × 10.3 mm (ZRC 2015.237), minor cheliped; N, Statommatia malagasy n. sp., Madagascar: male 8.8 × 11.0 mm (MNHN-IU- 2010 - 4370 b), minor cheliped.

FIGURE 47. Chelae of species of Tenagopelta n. gen. A, B, T. pacifica n. sp., Philippines: holotype male 10.3 × 11.9 mm (NMCR); C, D, T. brachyphallus n. sp., Australia: paratype male 6.9 × 7.6 mm (NMV J 54594); E ‒ H, T. potens, Papua New Guinea: male 11.8 × 13.8 mm (MNHN-IU- 2011 - 1504); I, J, T. potens, Papua New Guinea: male 8.8 × 10.0 mm (ZRC 2015.242).

FIGURE 54. Anterior thoracic sternum and male pleon of species of Statommatia n. gen. and Tenagopelta n. gen. A, Statommatia apta, Philippines: holotype 7.8 × 9.4 mm (USNM 46389); B, Statommatia apta, Philippines: male 5.9 × 7.1 mm (ZRC 2015.239); C, Statommatia malagasy n. sp., Madagascar: holotype male 9.9 × 12.4 mm (MNHN-IU- 2010 - 4370 a); D, E, Statommatia knudseni, New Caledonia: holotype male 4.7 × 6.9 mm (ZMUC CRU- 6974); F, Tenagopelta pacifica n. sp., Philippines: holotype male 10.3 × 11.9 mm (NMCR); G, Tenagopelta brachyphallus n. sp., Australia: holotype male 6.1 × 6.9 mm (NMV J 61680); H, Tenagopelta potens, Papua New Guinea: male 11.8 × 13.8 mm (MNHN-IU- 2011 - 1504).

FIGURE 61. Thoracic sternites 7 and 8 and male pleon of species of Statommatia n. gen. and Tenagopelta n. gen. A, Statommatia apta, Philippines: male 5.9 × 7.1 mm (ZRC 2015.239); B, Statommatia knudseni, New Caledonia: holotype 4.7 × 6.9 mm (ZMUC CRU- 6974); C, Statommatia malagasy n. sp., Madagascar: holotype male 9.9 × 12.4 mm (MNHN-IU- 2010 - 4370 a); D, Statommatia granulosa n. sp., New Caledonia: holotype male 4.1 × 4.7 mm (MNHN-IU- 2013 - 9454); E, Tenagopelta pacifica n. sp., Philippines: holotype male 10.3 × 11.9 mm (NMCR); F, Tenagopelta brachyphallus n. sp., Australia: holotype male 6.1 × 6.9 mm (NMV J 61680); G, Tenagopelta potens, Papua New Guinea: male 11.8 × 13.8 mm (MNHN-IU- 2011 - 1504).

FIGURE 79. Gonopods of species of Tenagopelta n. gen. A ‒ E, T. pacifica n. sp., Philippines: paratype male 10.2 × 11.4 mm (ZRC 2015.212); F ‒ J, T. brachyphallus n. sp., Australia: holotype male 6.1 × 6.9 mm (NMV J 61680); K ‒ N, T. potens, Papua New Guinea: male 11.8 × 13.8 mm (MNHN-IU- 2011 - 1504). A, F, K, ventral view of left G 1; B, G, L, dorsal view of left G 1; C, H, M, ventral view of distal part of left G 1; D, I, N, dorsal view of distal part of left G 1; E, J, O, left G 2. Scales: A, B, E, F, G, J, K, L, O = 0.5 mm; C, D, H, I, M, N = 0.1 mm.

FIGURE 88. Female thoracic sternum and pleon of species of Statommatia n. gen., Tenagopelta n. gen., Microtopsis and Megaesthesius. A, Statommatia apta, Philippines: female 8.5 × 10.6 mm (ZRC 2015.238); B, Statommatia malagasy n. sp., Madagascar: paratype female 9.4 × 8.1 mm (ZRC 2015.215); C, Tenagopelta pacifica n. sp., Philippines: female 9.2 × 10.4 mm (ZRC 2015.187); D, Tenagopelta brachyphallus n. sp., Australia: female 6.9 × 7.6 mm (NMV J 61680); E, Microtopsis takedai, Japan: paratype female 3.6 × 2.7 mm (ZRC 2012.0146); F, Megaesthesius sagedae, Singapore: female 3.0 × 3.6 mm (ZRC 2013.1804); G, Megaesthesius migmus, Philippines: paratype female 3.9 × 4.5 mm (ZRC 2015.245); H, Alainthesius bertrandi n. sp., Papua New Guinea: female 5.6 × 6.9 mm (MNHN-IU- 2013 - 9012). Vulvae exposed in E.

FIGURE 91. Vulvae of species of Hephthopelta, Angustopelta n. gen., Chinommatia n. gen., Statommatia n. gen. and Tenagopelta n. gen. A, Hephthopelta lugubris, Australia: ovigerous female 6.3 × 6.6 mm (NMV J 61083); B, Angustopelta aurita, Philippines: female 8.7 × 10.0 mm (ZRC 2015.253); C, Angustopelta robusta n. sp., Vanuatu: paratype female 13.4 × 15.1 mm (MNHN-IU- 2010 - 5616); D, Chinommatia cavimanus, Philippines: female 7.6 × 9.0 mm (ZRC 2015.228); E, Statommatia apta, Philippines: female 8.5 × 10.6 mm (ZRC 2015.238); F, Statommatia malagasy n. sp., Madagascar: paratype female 9.4 × 8.1 mm (ZRC 2015.215); G, Tenagopelta pacifica n. sp., Philippines: female 9.2 × 10.4 mm (ZRC 2015.187); H, Tenagopelta brachyphallus n. sp., Australia: female 6.9 × 7.6 mm (NMV J 61680).

FIGURE 102. Tenagopelta pacifica n. sp., Philippines. A, B, male 11.8 × 13.7 mm (ZRC 2015.189) [P. K. L. Ng]; C, male 9.1 × 9.6 mm (ZRC 2015.190) [T. - Y. Chan]; D, paratype female 8.4 × 9.7 mm (ZRC 2015.201) [T. - Y. Chan]; E, young female 6.9 × 7.7 mm (ZRC 2015.198) [T. - Y. Chan]; F, paratype female 6.6 × 6.9 mm (ZRC 2015.200) [T. - Y. Chan].