Chasmocarcinus

Ng, Peter K. L. & Castro, Peter, 2016, Revision of the family Chasmocarcinidae Serène, 1964 (Crustacea, Brachyura, Goneplacoidea), Zootaxa 4209 (1), pp. 1-182 : 13-14

Key to species of Chasmocarcinus

1. Western Atlantic (Gulf of Mexico, Caribbean Sea to Brazil) in distribution....................................... 2

- Tropical Eastern Pacific (Lower California to Peru) in distribution............................................. 8

2. Anterolateral margins of carapace smooth, without conspicuous tubercles, convex (e.g., Fig. 21 A).................... 3

- Anterolateral margins of carapace elevated, with conspicuous tubercles, granules, or setose ridge (e.g., Fig. 21 C).........4

3. Anterior third portion of carapace proportionally narrow, anterior margin conspicuously narrower than median portion ( Fig. 2 A‒D). Fingers of major chela of large males elongated, dactylus clearly longer than propodus ( Fig. 35 A, C), curved in dorsal view ( Figs. 2 A, B). Third maxilliped ischium elongated ( Fig. 28 A‒C) [West Indies to Brazil]................. C. typicus

- Anterior third portion of carapace nearly as wide as median portion ( Fig. 3 A, B). Fingers of major chela of large males not elongated, dactylus only slightly longer than propodus ( Fig. 35 I), straight in dorsal view ( Fig. 3 A, B); third maxilliped ischium rectangular ( Fig. 28 F) [Gulf of Mexico]............................................................ C. chacei

4. Dorsal surface of chelipeds with conspicuous setae ( Fig. 3 G). Anterolateral margins of carapace with low, setose ridge ( Fig. 21 H) [ Brazil]............................................................................... C. hirsutipes

- Dorsal surface of chelipeds smooth or with sparse setae or smooth (e.g., Fig. 3 E). Anterolateral margin of carapace with conspicuously raised, granular ridge, row of setae absent (e.g., Fig. 21 C, D)......................................... 5

5. Fingers of major chela of large males arched, leaving wide, circular gap ( Fig. 35 E), curved in dorsal view (Coelho & Coelho 1998: figs. 1a, 2c). Dorsal surface of cheliped propodus of large males eroded ( Fig. 35 E) [ Brazil]............. C. arcuatus

- Fingers of major chela of large males straight or slightly curved, not leaving wide, circular gap (e.g., Fig. 35 K). Dorsal surface of cheliped propodus of large males smooth............................................................... 6

6. Carapace proportionally wide along anterior third, almost as wide as posterior portion ( Fig. 3 C‒E) [Florida and West Indies to Brazil]................................................................................... C. cylindricus

- Carapace conspicuously narrower along anterior third than posterior portion (e.g., Fig. 4 G).......................... 7

7. Orbits, eye peduncles proportionally short ( Fig. 22 D). Male telson proportionally short, broad ( Fig. 50 E) [ Brazil]........................................................................................................ C. meloi

- Orbits, eye peduncles proportionally long ( Fig. 22 E). Male telson proportionally long, narrow ( Fig. 50 F) [Gulf of Mexico].......................................................................................... C. mississipiensis

8. Ambulatory legs proportionally short, merus wide, stout (e.g., Fig. 4 A). Fingers of major chela of large males almost straight ( Fig. 36 E, G) [Gulf of California to Peru]............................................................ C. latipes

- Ambulatory legs proportionally long, merus slender ( Fig. 4 F). Fingers of major chela of large males gently or prominently curved (e.g., Fig. 36 A)................................................................................. 9

9. Pterygostomial region prominent, bulging, clearly visible from dorsal view ( Fig. 5 C). Fingers of major chela of large males prominently curved, slender, long ( Fig. 36 A) [Pacific coast of Costa Rica]......................... C. gemmatus n. sp.

- Pterygostomial region not prominent, not visible from dorsal view ( Fig. 4 F). Fingers of major chela of large males relatively short, slightly curved ( Fig. 36 I) [Pacific coast of Costa Rica to Ecuador]................................. C. longipes

Figures

FIGURE 2. Overall dorsal view of species of Chasmocarcinus. A, C. typicus, Trinidad: holotype male 7.8 × 8.7 mm (USNM 6901); B, C. typicus, Trinidad: paratype male 4.1 × 4.7 mm (USNM 6901); C, C. typicus, Brazil: male 4.0 × 5.1 mm (MCZ CRU- 10993, holotype of C. rathbuni); D, C. typicus, Brazil: female 8.6 × 10.5 mm (ZRC 2015.211); E, C. arcuatus, Brazil: male 5.7 × 7.7 mm (ZRC 2015.221); F, C. arcuatus, Brazil: female 4.4 × 6.2 mm (ZRC 2015.222); G, C. arcuatus, Brazil: male 3.7 × 5.1 mm (ZRC 2015.220); H, C. arcuatus, Brazil: ovigerous female 4.6 × 6.1 mm (ZRC 2015.220).

FIGURE 3. Overall dorsal view of species of Chasmocarcinus. A, C. chacei, Gulf of Mexico: male 6.6 × 8.0 mm (USNM 61489); B, C. chacei, Gulf of Mexico: female 7.8 × 9.5 mm (USNM 61489); C, C. cylindricus, Jamaica: male 3.6 × 4.9 mm (USNM 42942); D, C. cylindricus, Puerto Rico: neotype female 4.6 × 6.1 mm (USNM 23765); E, C. cylindricus, Puerto Rico: female 6.9 × 9.2 mm (USNM 24551); F, 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. 5 a).

FIGURE 4. Overall dorsal view of species of Chasmocarcinus. A, C. latipes, Mexico: holotype female 12.4 × 14.4 mm (USNM 21592); B, C. latipes, Ecuador: male 10.5 × 14.5 mm (AMNH 1941 - 10668); C, C. latipes, Ecuador: male 10.5 × 14.3 mm (AMNH 1941 - 10668); D, C. latipes, Mexico: female 9.2 × 13.0 mm (AMNH 16262, holotype female of Chasmocarcinus ferrugineus Glassell, 1936); E, C. latipes, Mexico: female 7.5 × 10.5 mm (AMNH 16262, paratype female of Chasmocarcinus ferrugineus Glassell, 1936); F, C. longipes, Colombia: paratype male 5.5 × 6.4 mm (USNM 78785); G, C. meloi, Brazil: holotype male 5.3 × 6.2 mm (after Coelho & Coelho 1998: fig. 8 a); H, C. mississippiensis, Gulf of Mexico: holotype male 8.3 × 10.4 mm (USNM 64074).

FIGURE 5. Overall dorsal view of species of Chasmocarcinus, Amboplax n. gen. and Deltopelta n. gen. A, Amboplax peresi, Brazil: male 5.1 × 6.4 mm (ZRC 2015.217); B, Amboplax peresi, Brazil: ovigerous female 4.9 × 6.2 mm (ZRC 2015.217); C, Chasmocarcinus gemmatus n. sp., Costa Rica: male 7.7 × 11.6 mm (SIO C 1205); D, Chasmocarcinus latipes, Ecuador: male 10.5 × 14.5 mm (AMNH 1941 - 10668); E, Deltopelta obliquus, A, Bahamas: holotype male 5.2 × 5.1 mm (USNM 20509); F, Deltopelta obliquus, Belize: female 10.7 × 13.0 mm (PMNH, holotype of Hephthopelta superba); G, Deltopelta obliquus, Belize: female 10.7 × 13.0 mm (PMNH, holotype of Hephthopelta superba, after Boone 1927: fig. 5).

FIGURE 21. Frontal view of cephalothorax of species of Chasmocarcinus. A, C. typicus, Trinidad: holotype male 7.8 × 8.7 mm (USNM 6901); B C. arcuatus, Brazil: male 5.7 × 7.7 mm (ZRC 2015.221); C, 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, Puerto Rico: neotype female 4.6 × 6.1 mm (USNM 23765); G, C. gemmatus n. sp., Costa Rica: male 7.7 × 11.6 mm (SIO C 1205); H, C. hirsutipes, Brazil: holotype female 6.6 × 7.0 mm (after Coelho & Coelho 1998: fig. 5 c).

FIGURE 22. Frontal view of cephalothorax of species of Chasmocarcinus, Amboplax n. gen. and Deltopelta n. gen. A, Chasmocarcinus latipes, Mexico: holotype female 12.4 × 14.4 mm (USNM 21592); B, Chasmocarcinus latipes, Mexico: female 9.2 × 13.0 mm (AMNH 16262, holotype female of Chasmocarcinus ferrugineus Glassell, 1936); C, Chasmocarcinus longipes, Colombia: paratype male 5.5 × 6.4 mm (USNM 78785); D, Chasmocarcinus meloi, Brazil: holotype female 5.3 × 6.2 mm (after Coelho & Coelho 1998: fig. 8 b); E, Chasmocarcinus mississippiensis, Gulf of Mexico: holotype male 8.3 × 10.4 mm (USNM 64074); F, 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 28. Third maxilliped of species of Chasmocarcinus and Amboplax n. gen. A, Chasmocarcinus typicus, Trinidad: holotype male 7.8 × 8.7 mm (USNM 6901); B, Chasmocarcinus typicus, Brazil: male 4.0 × 5.1 mm (MCZ CRU- 10993, holotype of Chasmocarcinus rathbuni); C, Chasmocarcinus typicus, Brazil: male 9.4 × 12.1 mm (ZRC 2015.211); D, Chasmocarcinus arcuatus, Brazil: male 5.7 × 7.7 mm (ZRC 2015.221); E, Chasmocarcinus arcuatus, Brazil: male 3.7 × 5.1 mm (ZRC 2015.220); F, Chasmocarcinus chacei, Gulf of Mexico: female 7.8 × 9.5 mm (USNM 61489); G, Chasmocarcinus cylindricus, Puerto Rico: female 6.9 × 9.2 mm (USNM 24551); H, Amboplax peresi, Brazil: male 5.1 × 6.4 mm (ZRC 2015.217).

FIGURE 35. Chelae 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, D, C. typicus, Trinidad: paratype male 7.1 × 9.4 mm (USNM 6901); E, F, C. arcuatus, Brazil: holotype male 5.5 × 6.8 mm (after Coelho & Coelho 1998: figs. 2 d, 3 e); G, H, C. arcuatus, Brazil: male 3.7 × 5.1 mm (ZRC 2015.220); I, J, C. chacei, Gulf of Mexico: male 6.6 × 8.0 mm (USNM 61489); K, L, C. cylindricus, Jamaica: male 3.6 × 4.9 mm (USNM 42942).

FIGURE 36. Chelae of species of Chasmocarcinus. A, B, C. gemmatus n. sp., Costa Rica: male 7.7 × 11.6 mm (SIO C 1205); C, D, C. hirsutipes, Brazil: holotype male 6.6 × 7.0 mm (after Coelho & Coelho 1998: fig. 6 e, f); E, C. latipes, Mexico: holotype female 12.4 × 14.4 mm (USNM 21592); F, C. latipes, Mexico: female 9.2 × 13.0 mm (AMNH 16262, holotype female of Chasmocarcinus ferrugineus Glassell, 1936); G, H, C. latipes, Ecuador: male 10.5 × 14.5 mm (AMNH 1941 - 10668); I, J, C. longipes, Colombia: paratype male 5.5 × 6.4 mm (USNM 78785).

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. 9 d); 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).