Chasmocarcinus

Abstract

Key to species of <i>Chasmocarcinus</i> <p>1. Western Atlantic (Gulf of Mexico, Caribbean Sea to Brazil) in distribution....................................... 2</p> <p>- Tropical Eastern Pacific (Lower California to Peru) in distribution............................................. 8</p> <p>2. Anterolateral margins of carapace smooth, without conspicuous tubercles, convex (e.g., Fig. 21 A).................... 3</p> <p>- Anterolateral margins of carapace elevated, with conspicuous tubercles, granules, or setose ridge (e.g., Fig. 21 C).........4</p> <p> 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]................. <i>C. typicus</i></p> <p> - 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]............................................................ <i>C. chacei</i></p> <p> 4. Dorsal surface of chelipeds with conspicuous setae (Fig. 3 G). Anterolateral margins of carapace with low, setose ridge (Fig. 21 H) [Brazil]............................................................................... <i>C. hirsutipes</i></p> <p>- 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</p> <p> 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]............. <i>C. arcuatus</i></p> <p>- 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</p> <p> 6. Carapace proportionally wide along anterior third, almost as wide as posterior portion (Fig. 3 C‒E) [Florida and West Indies to Brazil]................................................................................... <i>C. cylindricus</i></p> <p>- Carapace conspicuously narrower along anterior third than posterior portion (e.g., Fig. 4 G).......................... 7</p> <p> 7. Orbits, eye peduncles proportionally short (Fig. 22 D). Male telson proportionally short, broad (Fig. 50 E) [Brazil]........................................................................................................ <i>C. meloi</i></p> <p> - Orbits, eye peduncles proportionally long (Fig. 22 E). Male telson proportionally long, narrow (Fig. 50 F) [Gulf of Mexico].......................................................................................... <i>C. mississipiensis</i></p> <p> 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]............................................................ <i>C. latipes</i></p> <p>- 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</p> <p> 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]......................... <i>C. gemmatus</i> <b>n. sp.</b></p> <p> - 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]................................. <i>C. longipes</i></p>Published as part of <i>Ng, Peter K. L. & Castro, Peter, 2016, Revision of the family Chasmocarcinidae Serène, 1964 (Crustacea, Brachyura, Goneplacoidea), pp. 1-182 in Zootaxa 4209 (1)</i> on pages 13-14, DOI: 10.11646/zootaxa.4209.1.1, <a href="http://zenodo.org/record/272646">http://zenodo.org/record/272646</a&gt