Revision of the family Chasmocarcinidae Serène, 1964 (Crustacea, Brachyura, Goneplacoidea) Ng, Peter K. L. Castro, Peter Zootaxa 2016 4209 1 1 182 666GC [151,421,1842,1868] Malacostraca Chasmocarcinidae Alainthesius Animalia Decapoda 113 114 Arthropoda species bertrandi sp. nov.     Typematerial. Holotypemale (3.3 × 4.1 mm) (MNHN-IU-2013-9073), New Caledonia, MUSORSTOM 4, stn CC174, 19°0.3’S, 163°18.5’E,  365 m,  17.09.1985.   FIGURE 41.Chelae of species of  Angustopelta  n. gen.A, B,  A. aurita, Philippines: male 9.2 × 10.6 mm (ZRC 2015.250); C, D,  A. cribrorum, Japan: holotype male 13.6 × 14.9 mm (USNM 46388); E, F,  A. cribrorum, Taiwan: male 9.9 × 11.6 mm (ZRC 2015.214); G, H,  A. robusta  n. sp., Vanuatu: holotype male 9.3 × 10.7 mm (MNHN-IU-2010-5616); I, J,  A. modesta  n. sp., Solomon Islands: holotype male 13.3 × 15.1 mm (MNHU-IU-2013-9038).   FIGURE 42.P4, P5, 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), minorcheliped; I,  Tenagopelta pacifica  n. sp., Indonesia: male 11.0 × 12.4 mm (MNHU-IU-2013-9053), minorcheliped; J,  Chinommatia cavimanus, Philippines: male 9.7 × 11.5 mm (ZRC 2015.234), minorcheliped; K,  Chinommatia cavimanus, Philippines: male 7.6 × 9.3 mm (ZRC 2015.231), minorcheliped; 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), minorcheliped; N,  Statommatia malagasy  n. sp., Madagascar: male 8.8 × 11.0 mm (MNHN-IU-2010-4370b), minorcheliped.   FIGURE 43.Chelae of species of  Chinommatia  n. gen.A, B,  C. cavimanus, Philippines: male 10.1 × 12.2 mm (ZRC 2015.228); C, D,  C. bruuni, Indonesia: 1 male 3.4 × 4.0 mm (ZMUC CRU-1524); E, F,  C. bicuspida  n. sp., Fiji: male 12.7 × 10.6 mm (MNHN-IU-2013-9056); G,  C. bicuspida  n. sp., Papua New Guinea: holotype male 10.7 × 12.9 mm (MNHN-IU- 2011-0954); H,  C. littoralis, Indonesia: holotype female 3.5 × 4.9 mm (NNM-ZMA); I, J,  C. turpis  n. sp., Vanuatu: holotype male 3.1 × 4.3 mm (MNHU-IU-2013-9044).   FIGURE 44.Chela and ambulatory leg of species of  Chinommatia  n. gen.A, F,  C. cavimanus, Philippines: male 10.4 × 12.3 mm (ZRC 2015.227); B, E,  C. cavimanus, Philippines: male 10.1 × 12.2 mm (ZRC 2015.228); C, D, G,  C. bicuspida  n. sp., Fiji: male 10.6 × 12.7 mm (MNHN-IU-2013-9056); H,  C. bicuspida  n. sp., Papua New Guinea: paratype female 16.7 × 20.4 mm (MNHN-IU-2011-3461). A‒D, ventral view of minorchela; E‒H, dorsal view of left P3.  Other material examined. Papua New Guinea.  PAPUA  NIUIGINI2012: 1 female(5.6 × 6.9 mm) (MNHN- IU-2013-9012), west KranketI., stn CP3949, 05°12’S, 145°51’E,  380‒407 m,  28.11.2012.    New Caledonia. MUSORSTOM 6: 1 female, carapace partially broken (MNHN-IU-2013-9452), Loyalty Is., stn DW439, 20°46.4’S, 167°17.4’E,  288 m,  19.02.1989; 1 male (carapace partially broken, 3.4 mmcarapace width) (MNHN-IU-2013-9074), Loyalty Is., stn DW442, 20°53.7’S, 167°17.10’E, 200 m, 19.02.1989.— EXBODI: 1 female(3.4 × 4.0 mm) (MNHN-IU-2013-9007), Ounia Pass, stn CP3826, 21°52’S, 166°51’E,  354‒509 m, 0 7.09.2011.     Fiji. BORDAU 1: 2 females(4.1 × 4.5 mm, 3.5 × 4.1 mm) (MNHN-IU-2013-9070), Yangasa Cluster, stn DW1496, 18°43.0’S, 178°23.0’E,  392‒407 m,  12.03.1999.   Diagnosis. Carapace ( Fig. 20E‒H) subquadrate, 1.1‒1.2 wider than long; front bilobed, with median cleft; dorsal surface smooth. Lateral margins straight, armed with small teeth arranged in 3 or 4 lobes. Long orbits, eye peduncle conspicuously long ( Fig. 27E, F), immobile, cornea reduced, non-pigmented. Epistome ( Figs. 19U, V; 27F) compressed, posterior margin with broad median lobe with fissure, straight lateral margins without fissures. Antennule ( Fig. 27E, F) greatly enlarged, particularly in males. Third maxillipeds ( Fig. 34F) nearly fill buccal cavern when closed; merus subtriangular, outer margin smooth; ischium subquadrate, outer margin smooth, longer than merus. Chelipeds ( Figs. 20G; 48G, H) subequal in length, nearly similar in both sexes; cutting margins of both chelae with broad, shallow teeth in both sexes ( Fig. 48G, H). Inner margin of cheliped carpus ( Fig. 20H) with one or more small, sharp tubercles or teeth. Proportionally long ambulatory legs ( Fig. 20E, G), P5 merus not reaching front when folded, minute teeth on anterior or posterior or both margins of most articles. Fused thoracic sternites 1, 2 ( Fig. 55F) broadly triangular, proportionally wide, short. Male pleon ( Fig. 62D) with lateral margins of fused somites 3–5, somite 6, slightly convex; telson proportionally long. Male thoracic sternite 8 ( Figs. 19Y; 62D) proportionally long, rectangular; “supplementary plate” narrow, short, slightly longer at rounded   FIGURE 49.Anterior thoracic sternum and male pleon of species of  Chasmocarcinus. A,  C. typicus, Trinidad: holotype male 7.8 × 8.7 mm (USNM 6901); B,  C. typicus, Brazil: male 4.0 × 5.1 mm (MCZ CRU-10993, holotype of  Chasmocarcinus rathbuni); C,  C. arcuatus, Brazil: male 5.7 × 7.7 mm (ZRC 2015.221); D,  C. arcuatus, Brazil: male 3.7 × 5.1 mm (ZRC 2015.220); E,  C. chacei, Gulf of Mexico: male 6.6 × 8.0 mm (USNM 61489); F,  C. cylindricus, Jamaica: male 3.6 × 4.9 mm (USNM 42942); G,  C. gemmatus  n. sp., Costa Rica: male 7.7 × 11.6 mm (SIO C 1205); H,  C. hirsutipes, Brazil: holotype male 6.6 × 7.0 mm (after Coelho & Coelho 1998: fig. 7c).   FIGURE 50.Anterior thoracic sternum and male pleon of species of  Chasmocarcinus, Amboplax  n. gen.and  Deltopelta  n. gen.A, C,  Chasmocarcinus latipes, Ecuador: male 10.5 × 14.5 mm (AMNH 1941-10668); B,  Chasmocarcinus longipes, Colombia: paratype male 5.5 × 6.4 mm (USNM 78785); D,  Chasmocarcinus latipes, D, Mexico: male 8.3 × 11.0 mm (SIO C 319); E,  Chasmocarcinus meloi, Brazil: holotype male 5.3 × 6.2 mm (after Coelho & Coelho 1998: fig. 9d); F,  Chasmocarcinus mississippiensis, Gulf of Mexico: male 7.2 × 8.8 mm (USNM 101082); G,  Amboplax peresi, Brazil: male 5.1 × 6.4 mm (ZRC 2015. 217); H,  Deltopelta obliquus, Bahamas: holotype male 5.2 × 5.1 mm (USNM 20509).   FIGURE 51.Anterior thoracic sternum and male pleon of species of  Camatopsisand  Chasmocarcinops. A,  Camatopsis rubida, Australia: male 8.3 × 8.5 mm (NMV J54591); B,  Camatopsis africana  n. sp., Madagascar: holotype male 5.7 × 6.9 mm (MNHN-IU-2010-1574); C,  Camatopsis leptomerus  n. sp., Philippines: holotype male 10.5 × 11.3 mm (NMCR); D,  Camatopsis thula  n. sp., Taiwan: holotype male 8.9 × 9.3 mm (ZRC 1999.0662); E,  Camatopsis valida  n. sp., Fiji: holotype male 3.6 × 4.9 mm (MNHN-IU-2013-9067); F,  Chasmocarcinops gelasimoides, Singapore: male 9.5 × 10.3 mm (ZRC 2000.1341). outer margin. Outer (ventral) surface of penis calcified, resembling plate between “supplementary plate”, sternite 8 ( Fig. 19Y). G1( Fig. 83D–G) slender, distal segment, straight, with spinules. G2 ( Fig. 83H) about 1/2 as long as G1, stout, distal segment long, wide, almost as long as basal segment, directed inwards. Somites of female pleon ( Fig. 88H) with slightly convex lateral margins; telson proportionally long. Sterno-pleonal cavity of female ( Fig. 92D) deep, vulvae far apart from each other on outer margins of cavity close to suture 5/6.   Etymology. The species is named after Bertrand Richer de Forges, whose collections in New Caledoniaand the western Pacific have substantially advanced our knowledge of brachyuran diversity.   Remarks. The species is superficially similar to  Megaesthesius migmus  n. sp.and share a similar anterolateral armature.  Alainthesius bertrandi  n. sp.can nevertheless be immediately separated by its more transversely rectangular carapace ( Fig. 20E‒H) (more quadrate in  M. migmus  n. sp., Fig. 20A, B), and the dorsal margin of the carpus of ambulatory legs 2‒5 is lined with spinules ( Fig. 20E) (unarmed in  M. migmus  n. sp., Fig. 20A, B). The most significant difference is with the G2 structure, which in  A. bertrandi  n. sp.is short ( Fig. 83H) but is markedly long in  M. migmus  n. sp.( Fig. 82F). For this reason,  A. bertrandi  n. sp.is placed in  Alainthesius  n. gen.   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-2010-4370a); 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 J61680); H,  Tenagopelta potens, Papua New Guinea: male 11.8 × 13.8 mm (MNHN-IU-2011-1504).   FIGURE 55.Anterior thoracic sternum and male pleon of species of  Statommatia  n. gen.,  Microtopsisand  Megaesthesius. A,  Statommatia granulosa  n. sp., New Caledonia: holotype male 4.1 × 4.7 mm (MNHN-IU-2013-9454); B,  Microtopsis takedai, Japan: paratype male, carapace damaged (ZRC 2012.0146); C,  Megaesthesius sagedae, Singapore: male 2.5 × 3.0 mm (ZRC 1995.885); D,  Megaesthesius migmus  n. sp., Philippines: holotype male 4.4 × 4.9 mm (NMCR); E,  Alainthesius signatus  n. sp., Madagascar: holotype male 2.5 × 3.3 mm (MNHN-IU-2013-9472); F,  Alainthesius bertrandi  n. sp., New Caledonia: holotype male 3.3 × 4.1 mm (MNHN-IU-2013-9073). A female from  PapuaNew Guinea, unusually large for a megaesthesiine (5.6 × 6.9 mm, MNHN-IU-2013- 9012) ( Fig. 20G) shows a pereiopod spinulation of that is somewhat different from that of the other specimens of the species that were examined, most especially a row of small teeth on the inner margin of the cheliped carpus (one tooth in other specimens). This difference is perhaps size related.   Alainthesius bertrandi  n. sp.can easily be distinguished from its only known congener,  A. signatus  n. sp., by its more granular carapace surface ( Figs. 20E–H, 27E, F) (smoother in  A. signatus  n. sp., Figs. 20C, D, 27D) and differently structured G1 ( Fig. 83D–G versus Fig. 83A, B in  A. signatus).  Alainthesius bertrandi  n. sp.is also found at greater depths ( 200–509 m) than its congener ( 72 m).   Distribution. WesternPacific Ocean (  PapuaNew Guinea, New Caledonia, and Fiji). Depth: 200– 509 m. 1424726083 1985-09-17 New Caledonia 365 -19.005 New Caledonia 127 163.30833 113 114 2 holotype 1424726086 2012-11-28 NIUIGINI Kranket I. 394 -5.2 west Kranket 1305 145.85 117 118 NIUIGINI 2012 1 1 PAPUA 1424726081 1989-02-19 New Caledonia 288 -20.773333 New Caledonia 126 167.29 117 118 1 1 1424726103 New Caledonia 431 -21.866667 Ounia Pass 1262 166.85 117 118 1 1 1424726108 1999-12-03 Fiji 400 -18.716667 Yangasa Cluster 127 178.38333 121 122 2 2