Rediagnosis of the squat lobster genus Gastroptychus Caullery, 1896, with a new genus Sternostylus and a new family Sternostylidae (Crustacea: Decapoda: Anomura: Chirostyloidea) Author Baba, Keiji Author Ahyong, Shane T. Author Schnabel, Kareen E. text Zootaxa 2018 2018-11-20 4524 1 77 86 journal article 27935 10.11646/zootaxa.4524.1.5 a42793f8-373b-4a16-8e42-c7571a931861 1175-5326 2610351 C25BE702-567D-4C6C-A8AC-91E66CC75F4C Gastroptychus Caullery, 1896 (Figs. 1B, 3A) Ptychogaster A. Milne Edwards, 1880 : 63 .— Henderson, 1888 : 170 (part).— Alcock, 1901 : 280 (part). Gastroptychus Caullery, 1896 : 390 (replacement name for Ptychogaster A. Milne Edwards, 1880 , preoccupied by Ptychogaster Pomel, 1847 (Reptilia: Chelonia, fossil)).— Miyake & Baba, 1968 : 379 (part).— Poore, 2004 : 221 (part).— Baba, 2005 : 19 (part).— Macpherson & Baba, 2011 : 49 (part). Chirostylus — Zariquiey Alvarez, 1968 : 261 (part).— Van Dam, 1933 : 12 (part). Type species . Ptychogaster spinifer A. Milne Edwards, 1880 . Diagnosis . Carapace with dorsal and lateral spines; dorsal surface lacking transverse striae; lateral orbital spine present or absent; posterior lateral margin weakly or barely excavated. Rostrum spiniform, basal part subtriangular. Anterior margin of sternal plastron (at sternite 3 immediately behind maxillipeds 3) feebly or strongly concave with 2 or more spines, preceded by excavated sternum; sternite 4 with strong lateral spine on each side. Sternal plastron concavely constricted between sternites 4–5 (often hourglass-shaped). Antennal peduncle slender, acicle present or absent. Mandible incisor margin serrated. Maxilliped 1 exopod with smooth, non-annulated flagellum. Pereopods 1–4 long and slender, with numerous spines usually arranged in longitudinal rows. Species included . Chirostylus affinis Chace, 1942 (western Atlantic); Gastroptychus brachyterus Baba, 2005 (western Pacific); Gastroptychus brevipropodus Baba, 1991 (western Pacific); Ptychogaster laevis Henderson, 1885 (western Pacific); Gastroptychus novaezelandiae Baba, 1974 (western Pacific); Gastroptychus paucispina Baba, 1991 (western Pacific); Ptychogaster spinifer A. Milne Edwards, 1880 (western Atlantic); Chirostylus Remarks . Nine species are now assigned to Gastroptychus sensu stricto . Baba (2005) mistakenly placed Ptychogaster spinifer in the other group of species of Gastroptychus , transferred herein to Sternostylus . Three species ( G. brachyterus , G. brevipropodus , G. novaezelandiae ) are unusual in the genus in having the pereopods 2–4 propodi extremely short relative to the carpi. Molecular data are available for G. novaezelandiae (see Schnabel et al . 2011 ; Bracken-Grissom et al . 2013 ) but a comparison of genetic differentiation from other members of this genus is yet to be undertaken.