Carcinoplax, H. MILNE EDWARDS, 1852

Ng, Peter K. L. & Castro, Peter, 2020, A revision of Carcinoplax abyssicola (Miers, 1885) and seven related species of Carcinoplax H. Milne Edwards, 1852, with the description of two new species and an updated key to the genus (Crustacea, Decapoda, Brachyura, Goneplacidae), Zoosystema 42 (17), pp. 239-284 : 281-282

publication ID	https://doi.org/10.5252/zoosystema2020v42a17
publication LSID	urn:lsid:zoobank.org:pub:52C73176-6867-4415-A6FA-BAD328E9781D
DOI	https://doi.org/10.5281/zenodo.4525521
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treatment provided by	Felipe (2020-06-15 16:47:03, last updated 2024-11-27 05:40:10)
scientific name	Carcinoplax
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KEY TO SPECIES OF CARCINOPLAX H. MILNE EDWARDS, 1852 View in CoL

1. One well-developed, anteriorly curved anterolateral tooth posterior to outer orbital tooth on each side of carapace ( Guinot 1989: pl. 13, fig. F, as C. eurysternum Guinot & Richer de Forges, 1981 View in CoL ) ................................. ..................................................................................................................... C. ischurodous (Stebbing, 1923) View in CoL .

— Two anterolateral teeth posterior to outer orbital angle (1 or 2 anterolateral teeth may be greatly reduced or even obsolete in some large individuals) .............................................................................................................. 2

2. Adults attain large size (cl more than 30-40 mm), with reduced outer orbital and anterolateral teeth (obsolete in largest individuals), rounded anterolateral borders (carapace becoming almost spherical), and much enlarged chelipeds (P1) with conspicuously elongated meri, propodi ......................................................................... 3

— Adults do not attain large size (cl less than 30-40 mm), do not show progressive reduction in outer orbital (if present) and anterolateral teeth with corresponding rounded anterolateral borders and chelipeds (P1) with conspicuously elongated meri, propodi ............................................................................................................. 8

3. Low, conspicuous granules on carapace; small individuals with triangular, acute, curved, acute first and second anterolateral teeth ( Guinot 1989: pl. 1, fig. D); uniformly red to dark red-brown carapace in life, bright redbrown markings on chelipeds (P1) ............................................................... C. longimana (De Haan, 1833) View in CoL .

— No conspicuous granules on carapace; small individuals with narrow, acute anterolateral teeth, or small, blunt first anterolateral teeth; in life, carapace not uniformly red or dark-red brown ............................................. 4

4. Small- to medium-size individuals with 2 narrow, acute, spine-like anterolateral teeth below acute, conspicuous outer orbital tooth on each side of carapace ( Guinot 1989: pl. 1, figs G, H; Hsueh & Huang 2002: fig. 6A); carapace nearly quadrate, with red, round spot on dorsal surface in most individuals when fresh ( Hsueh & Huang 2002: fig. 8B) ............................................................................................... C. indica Doflein, 1904 View in CoL .

— Small- to medium-size individuals with blunt first anterolateral tooth, second tooth curved, acute; carapace globose; never with red spot on carapace in life ........................................................................................... 5

5. Outer orbital angle with low tooth or absent; second anterolateral tooth short, low (more conspicuous in small individuals), not hook-like .......................................................................................................................... 6

— Outer orbital angle with distinct tooth; second anterolateral tooth usually distinct, elongated, hook-like .... 7

6. P2-P5 relatively short; anterolateral teeth may be low in larger individuals but always visible ( Ng & Mitra 2019: fig. 6C, D); purple-red vertical band across carapace from front to posterior border in life ( Hsueh & Huang 2002: fig. 8C); western Pacific ............................................................................ C. purpurea Rathbun, 1914 View in CoL .

— P2-P5 relatively longer; anterolateral tooth short, absent in large individuals ( Guinot 1989: fig. 9A-C; pl. 3, figs A, C, E); carapace uniformly colored in life; Red Sea and Persian Gulf ............. C. monodi Guinot, 1989 View in CoL .

7. G1 with rounded, truncated tip ( Ng & Mitra 2019: fig. 8K, L, N); western Pacific ..... C. sinica Chen, 1984 View in CoL . — G1 with pointed tip ( Ng & Mitra 2019: fig. 8E, F); Indian Ocean ................... C. mistio Ng & Mitra, 2019 View in CoL .

8. Carapace, chelipeds (P1), and P2-P5 covered with conspicuous short setae ................................................. 9

— Carapace, chelipeds (P1), and/or P2-P5 may have sparse setae, short tomentum, or mostly or completely devoid of conspicuous setae, or tomentum ........................................................................................................... 10

9. Conspicuous, acute tubercles on proximal portion of P1 propodi (may be absent in large individuals) ( Hsueh & Huang 2002: fig. 5E); distal quarter of fingers darkly pigmented; acute tooth on distal portion of P2-P5 meri ( Chen 1998: fig. 4-2; Hsueh & Huang 2002: fig. 5C); no conspicuous color pattern in life …....................... ...................................................................................................................... C. spinosissima Rathbun, 1914 View in CoL .

— Conspicuous, low, blunt tubercles on proximal portion of cheliped (P1) propodi ( Guinot 1989: pl. 6, fig. H); distal half of fingers darkly pigmented; distal portion of P2-P5 meri smooth; in life with orange reticulated lines on P1 and carapace (obvious when denuded) ............................................................. C. nana Guinot, 1989 View in CoL .

10. Carapace, chelipeds (P1), and P2-P5 covered with short tomentum (large individuals only on ambulatory legs) ( Hsueh & Huang 2002: fig. 7A) ............................................................................ C. tomentosa Sakai, 1969 View in CoL .

— Carapace, chelipeds (P1), and P2-P5 not covered with conspicuous short tomentum ................................ 11

11. Outer orbital angle without tooth or eminence; with 2 thin, spine-like anterolateral teeth ( Castro 2007: figs 4A, 5) ..................................................................................................................... C. tenuidentata Castro, 2007 View in CoL .

— Outer orbital angle ends in lobe or tooth; anterolateral teeth not thin, spine-like ...................................... 12

12. Front with slight median notch ( Guinot 1989: fig. 17) .................................... C. confragosa Rathbun, 1914 View in CoL . — Front straight, without distinct median notch. ........................................................................................... 13 13. Conspicuous, well-developed anterolateral teeth, with acute, anteriorly-oriented or hook-like tips ............ 18 — Relatively small, blunt, non-spinous anterolateral teeth ( Castro 2007: figs 7, 10) ...................................... 24

14. P2-P5 long, relatively slender, distal end of folded P5 merus extending beyond tip of second anterolateral tooth ......................................................................................................................................................... 15

— P2-P5 short, distal end of folded P5 merus only reaching or barely reaching tip of second anterolateral tooth .................................................................................................................................................................. 16

15. Two conspicuous, wide transverse ridges on dorsal surface of carapace ( Castro 2007: fig. 3); western Pacific .. ................................................................................................................................. C. cracens Castro, 2007 View in CoL .

— Dorsal surface of carapace evenly convex, without transverse ridges; eastern Indian Ocean ............................. .................................................................................................................. C. longipes (Wood-Mason, 1891) View in CoL .

16. Two conspicuous, wide transverse ridges on dorsal surface of carapace ............. C. inaequalis (Yokoya, 1933) View in CoL . — Dorsal surface of carapace evenly convex, without conspicuous ridges. ...................................................... 17

17. All anterolateral teeth anteriorly curved; narrow, J-shaped gap between outer orbital tooth and first anterolateral tooth ( Castro 2009: fig. 1A View FIG ); southwestern and central Pacific .............................. C. uncinata Castro, 2009 View in CoL .

— Anterolateral teeth sharp but not curved (only first one in rare cases); outer orbital angle often prominent, rounded. ................................................................................................................................................... 18

18. Posterior margin of epistome with median part pronounced, triangular, lateral margins conspicuously concave ( Fig. 21D View FIG ) ................................................................................................................................................. 19

— Posterior margin of epistome with truncated or nearly straight median part; lateral margins nearly straight or slightly sinuous ( Fig. 3D View FIG ) .......................................................................................................................... 20

19. Two transverse elevations across cardiac, gastric regions of carapace ( Figs 21C, D View FIG ; 22C, D View FIG ); western Pacific ... ............................................................................................................................................... C. jugum View in CoL n. sp.

— Dorsal surface of carapace evenly smooth, without transverse elevations; western Indian Ocean ..................... ...................................................................................................................... C. fasciata Ng & Kumar, 2009 View in CoL .

20. Outer, proximal margin of cheliped carpus with sharp tooth; western Pacific and eastern Indian Ocean ......... .................................................................................................................................. C. polita Guinot, 1989 View in CoL .

— Outer, proximal margin of cheliped carpus smooth, without tooth ........................................................... 21

21. P2-P5 proportionally short, stout, with distal end of folded P5 merus not reaching tip of second anterolateral tooth (e.g. Figs 10A View FIG ; 11A View FIG ; 19A View FIG ; 20A View FIG ) ........................................................................................................ 22

— P2-P5 proportionally long, slender, with distal end of folded P5 merus reaching tip of second anterolateral tooth (e.g. Figs 2A View FIG ; 3A View FIG ; 13A View FIG ; 14A View FIG ) ..................................................................................................................... 23

22. Posterior margin of epistome with median part not protruding ( Figs 19D View FIG ; 20D View FIG ); G1 elongated, distal half distinctly slender ( Fig. 25F View FIG ); southwestern Pacific .................................................................... C. adelphia View in CoL n. sp.

— Posterior margin of epistome with median part pronounced, protruding ( Figs 10D View FIG ; 11D View FIG ; 12D View FIG ); G1 relatively short, stout ( Fig. 25A, B View FIG ); northwestern Pacific ................................................. C. specularis Rathbun, 1914 View in CoL .

23. Fingers dark brown or black almost along their entire lengths ( Figs 2H View FIG ; 3I View FIG ; 4H View FIG ; 5H View FIG ); inner distal angle of carpus of cheliped dentiform ( Figs 2E, F View FIG ; 3F View FIG , 4F View FIG , 5E View FIG ); Indian Ocean and southwestern Pacific .................................. ............................................................................................................................ C. abyssicola ( Miers, 1885) View in CoL .

— Fingers dark brown or black along the distal two-thirds to half portions ( Figs 13I, J View FIG ; 14H View FIG ); inner distal angle of carpus of cheliped usually spiniform with tip narrow ( Figs 13F View FIG ; 14F View FIG ; 15E View FIG ); western Pacific ............................ ........................................................................................................................... C. verdensis Rathbun, 1914 View in CoL .

24. Outer, dorsal surface of cheliped (P1) propodi and carpi with conspicuous granular tubercles ( Castro 2007: fig. 8); P2-P5 relatively short ( Fig. 7 View FIG ), distal end of folded P5 merus only reaching tip of second anterolateral tooth; western Pacific ............................................................................................. C. tuberosa Castro, 2007 View in CoL .

— Outer, dorsal surface of chelipeds (P1) smooth; P2-P5 proportionally long ( Castro 2007: fig. 10), distal end of folded P5 merus extending beyond tip of second anterolateral tooth; central and southwestern Pacific ........... ................................................................................................................................ C. velutina Castro, 2007 View in CoL .

References

CASTRO P. 2007. - A reappraisal of the family Goneplacidae MacLeay, 1838 (Crustacea, Decapoda, Brachyura) and revision of the subfamily Goneplacinae, with the description of 10 new genera and 18 new species. Zoosystema 29 (4): 609 - 774.

CASTRO P. 2009. - Two new species of Carcinoplax H. Milne Edwards, 1852, and Pycnoplax Castro, 2007, from the western Pacific, and a description of the female of Thyraplax truncata Castro, 2007 (Crustacea, Decapoda, Brachyura, Goneplacidae). Zoosystema 31 (4): 949 - 957. https: // doi. org / 10.5252 / z 2009 n 4 a 9

CHEN H. 1984. - A study of the genus Carcinoplax (Crustacea, Decapoda: Goneplacidae) of Chinese waters. Oceanologia et Limnologia Sinica 15: 188 - 201, pl. 1 (in Chinese with English abstract).

CHEN H. 1998. - The Goneplacidae (Crustacea: Brachyura) from Nansha Islands and adjacent waters, in Studies on Marine Fauna and Flora and Biogeography of the Nansha Islands and Neighbouring Waters 3. Academia Sinica, Beijing: 265 - 316 (in Chinese with English abstract).

DOFLEIN F. 1904. - Brachyura. Wissenschaftliche Ergebnisse des Deutschen Tiefsee-Expedition auf dem Dempfer Valdivia 1898 - 1899, vol. 6: xiv + 314 p; Atlas: pls 1 - 58.

GUINOT D. 1989. - Le genre Carcinoplax H. Milne Edwards, 1852 (Crustacea, Brachyura: Goneplacidae), in FOREST J. (ed.), Resultats des campagnes MUSORSTOM volume 5. Museum national d'Histoire naturelle, Paris, 385 p. (Memoires du Museum national d'Histoire naturelle, Serie A - Zoologie (1950 - 1992); 144): 265 - 345.

HSUEH P. - W. & HUANG J. - F. 2002. - Crabs of the family Goneplacidae (Decapoda, Brachyura) from Taiwan. Crustaceana 75: 111 - 136. https: // doi. org / 10.1163 / 15685400252902344

MIERS E. J. 1885. - The Brachyura, in TIZARD T. H., MOSELEY H. N., BUCHANANJ. Y. & MURRAY J. (eds), Narrative of the cruise of H. M. S. Challenger with a general account of the scientific results of the expedition. Report on the Scientific Results of the Voyage of H. M. S. Challenger during the years 1873 - 1876 under the command of Captain George S. Nares, R. N., F. R. S. and the late Captain Frank Tourle Thomson, R. N. prepared under the Superintendence of the late Sir C. Wyville Thomson, Knt., F. R. S. & c. Regius Professor of Natural History in the University of Edinburgh Director of the civilian scientific staff on board and now of John Murray, one of the naturalists of the Expedition. Published by Order of Her Majesty's Government. London, Edinburgh and Dublin, Her Majesty Stationery Office. Narrative. 1 (2): 585 - 592. https: // doi. org / 10.5962 / bhl. title. 6513

MILNE EDWARDS H. 1852. - Observations sur les affinites zoologiques et la classification naturelle des Crustaces. Annales des Sciences naturelles, Zoologie, Serie 3, 18: 109 - 166, pls 3, 4. (second part in Annales des Sciences naturelles, Zoologie, Serie 3, 20: 163 - 228, pls 6 - 11 [1853]).

NG P. K. L. & MITRA S. 2019. - Carcinoplax mistio, a new species of goneplacid crab from the Indian Ocean (Decapoda: Brachyura: Goneplacoidea). Nauplius 27: 1 - 15. https: // doi. org / 10.1590 / 2358 - 2936 e 2019004

RATHBUN M. J. 1914. - A new genus and some new species of crabs of the family Goneplacidae. Scientific Results of the Philippine cruise of the Fisheries Streamer Albatross, 1907 - 1910 - No. 32. Proceedings of the United States National Museum 48 (2067): 137 - 154. https: // doi. org / 10.5479 / si. 00963801.2067.137

SAKAI T. 1969. - Two new genera and twenty-two new species of crabs from Japan. Proceedings of the Biological Society ofWashington 82: 243 - 280. https: // www. biodiversitylibrary. org / page / 34595262

Figures

FIG. 1. — Carcinoplax abyssicola (Miers,1885),holotype ♂ (8.2 × 10.0 mm) (NHM 84.31),Fiji:A, overall habitus;B, dorsal view of carapace;C, frontal view of cepha- lothorax; D, left third maxilliped; E, thoracic sternum and third maxillipeds; F, dorsal view of left cheliped; G, outer view of right chela; H, outer view of left chela.

FIG. 21. — Carcinoplax jugum n. sp., holotype ♂ (33.6 × 45.5 mm) (ZRC 2004.0777), Philippines: A, overall habitus; B, dorsal view of carapace; C, frontal view of cephalothorax; D, posterior margin of epistome; E, left third maxilliped; F, dorsal view of carpus of left cheliped; G, dorsal view of carpus of right cheliped; H, thoracic sternum and pleon; I, outer view of right chela; J, outer view of left chela.

FIG. 3. — Carcinoplax abyssicola (Miers, 1885), ♂ (11.0 × 15.5 mm) (MNHN-IU-2014-11529), Fiji: A, overall habitus; B, dorsal view of carapace; C, frontal view of cephalothorax; D, posterior margin of epistome; E, left third maxilliped; F, dorsal view of left cheliped; G, dorsal view of right cheliped; H, thoracic sternum and pleon; I, outer view of chelae.

FIG. 22. — Carcinoplax jugum n. sp.: A-C, F-J, paratype ♀ (25.1 × 32.5 mm) (ZRC 2006.0217), Philippines; D, E, paratype ♀ (26.9 × 35.4 mm) (ZRC 2018.1431), Philippines: A, overall habitus; B, E, dorsal view of carapace; C, frontal view of cephalothorax; D, posterior margin of epistome; F, dorsal view of carpus of right cheliped; G, thoracic sternum and pleon; H, sternopleonal cavity and vulvae; I, outer view of right chela; J, outer view of left chela.

FIG. 10. — Carcinoplax specularis Rathbun, 1914, holotype ♂ (16.7 × 23.0 mm) (USNM 46164), Philippines:A, overall habitus; B, dorsal view of carapace; C, frontal view of cephalothorax; D, posterior margin of epistome; E, left third maxilliped; F, right cheliped; G, thoracic sternum and pleon; H, outer view of chelae.

FIG. 11. — Carcinoplax specularis Rathbun, 1914, ♂ (18.4 × 25.8 mm) (ZRC 2001.0134), Taiwan: A, overall habitus; B, dorsal view of carapace; C, frontal view of cephalothorax; D, posterior margin of epistome; E, left third maxilliped; F, dorsal view of carpus of right cheliped; G, dorsal view of right chela; H, thoracic sternum and pleon; I, outer view of chelae.

FIG. 19. — Carcinoplax adelphia n. sp.,holotype ♂ (19.4 × 25.4 mm) (MNHN-IU-2016-8002), Vanuatu:A, overall habitus;B, dorsal view of carapace;C, frontal view of cephalothorax; D, posterior margin of epistome; E, left third maxilliped; F, dorsal view of right cheliped;G, thoracic sternum and pleon; H, outer view of chelae.

FIG. 20. — Carcinoplax adelphia n. sp., paratype ♀ (16.9 × 22.4 mm) (ZRC 2009.0992), Vanuatu: A, overall habitus; B, dorsal view of carapace; C, frontal view of cephalothorax; D, posterior margin of epistome; E, left third maxilliped; F, dorsal view of carpus of right cheliped; G, thoracic sternum and pleon; H, sternopleonal cavity and vulvae; I, outer view of chelae.

FIG. 2. — Carcinoplax abyssicola (Miers, 1885): A-H, ♂ (8.0 × 10.4 mm) (MNHN-IU-2014-11535), Fiji; I, ♂ (10.5 × 15.3 mm) (MNHN-IU-2014-11531), Fiji; A, overall habitus; B, I, dorsal view of carapace; C, frontal view of cephalothorax; D, left third maxilliped; E, dorsal view of left cheliped; F, dorsal view of right cheliped; G, thoracic sternum and pleon; H, outer view of chelae.

FIG. 13. — Carcinoplax verdensis Rathbun, 1914, holotype ovigerous ♀ (10.5 × 13.0 mm) (USNM 46167), Philippines: A, overall habitus; B, dorsal view of carapace; C, frontal view of cephalothorax; D, posterior margin of epistome; E, left third maxilliped; F, dorsal view of carpus of right cheliped; G, thoracic sternum and pleon; H, sternopleonal cavity and vulvae; I, outer view of right chela; J, outer view of left chela.

FIG. 14. — Carcinoplax verdensis Rathbun, 1914, ♂ (15.7 × 21.4 mm) (ZRC 2019.0549), Philippines: A, overall habitus; B, dorsal view of carapace; C, frontal view of cephalothorax; D, posterior margin of epistome; E, left third maxilliped; F, dorsal view of carpus of right cheliped; G, thoracic sternum and pleon; H, outer view of chelae.

FIG. 25. — Gonopods: A-E, Carcinoplax specularis Rathbun, 1914, holotype ♂ (16.7 × 23.0 mm) (USNM 46164), Philippines; F-I, C. adelphia n. sp., holotype ♂ (19.4 × 25.4 mm) (MNHN-IU-2016-8002), Vanuatu; J-P, C. fasciata Ng & Kumar, 2016, holotype ♂ (25.8 × 19.3 mm) (DABFUK), India; Q-T, C. jugum n. sp., holotype ♂ (33.6 × 45.5 mm) (ZRC 2004.0777), Philippines. A, right G1 (dorsal view), B, right g1 (ventral view); C, distal part of right G1 (ventral view); D, distal part of right G1 (dorsal view); E, right G2; F, J, Q, left G1 (ventral view); G, K, R, distal part of left G1 (ventral view); H, L, S, distal part of left G1 (dorsal view); I, M, D, Q, left G2; N, right G2; O, P, distal part of right G2. A, after Guinot (1989: fig. 34A). Scale bars: A, B, E, F, I, J, M, N, Q, T, 1.0 mm; C, D, G, H, K, L, R, S, 0.5 mm; O, P, 0.25 mm.

FIG. 12. — Carcinoplax specularis Rathbun, 1914, ♀ (12.4 × 16.7 mm) (MNHN-IU-2016-125), Taiwan: A, overall habitus;B, dorsal view of carapace;C, frontal view of cephalothorax; D, posterior margin of epistome; E, right third maxilliped; F, dorsal view of carpus of right cheliped; G, thoracic sternum and pleon; H, sternopleonal cavity and vulvae; I, outer view of chelae.

FIG. 4. — Carcinoplax abyssicola (Miers, 1885), ♂ (13.6 × 18.4 mm) (ZRC 2018.1415), Indonesia: A, overall habitus; B, dorsal view of carapace; C, frontal view of cephalothorax; D, posterior margin of epistome; E, left third maxilliped; F, dorsal view of carpus of right cheliped; G, thoracic sternum and pleon; H, outer view of chelae.

FIG. 5. — Carcinoplax abyssicola (Miers, 1885), ♀ (14.8 × 20.0 mm) (ZRC 2018.1415), Indonesia: A, overall habitus; B, dorsal view of carapace; C, frontal view of cephalothorax; D, left third maxilliped; E, dorsal view of carpus of right cheliped; F, thoracic sternum and pleon; G, sternopleonal cavity and vulvae; H, outer view of chelae.

FIG. 15. — Carcinoplax verdensis Rathbun, 1914, ♀ (16.3 × 21.9 mm) (ZRC 2019.0546),Philippines: A, overall habitus; B, dorsal view of carapace; C, frontal view of cephalothorax; D, left third maxilliped; E, dorsal view of carpus of right cheliped; F, thoracic sternum and pleon; G, sternopleonal cavity and vulvae.

FIG. 7. — Carcinoplax longipes (Wood-Mason, 1891), ♀ (11.9 × 15.1 mm) (USNM 46291), India: A, overall habitus; B, dorsal view of carapace; C, frontal view of cephalothorax; D, posterior margin of epistome; E, left third maxilliped;F, dorsal view of carpus of right cheliped;G, thoracic sternum and pleon;H, sternopleonal cavity and vulvae; I, outer view of chelae.