The taxonomy of spider crabs of the genera Eurynome, Choniognathus, Seiitaiodes and Kasagia (Crustacea: Brachyura: Majidae) from southwest Indian Ocean Author Forges, Bertrand Richer De 0000-0002-4554-7953 b.richerdeforges@gmail.com Author Lee, Bee Yan Author Ng, Peter K. L. 0000-0002-4554-7953 b.richerdeforges@gmail.com text Zootaxa 2021 2021-10-07 5048 3 301 333 journal article 4058 10.11646/zootaxa.5048.3.1 6cf7dece-9a31-4cba-9497-664a0ffac9d8 1175-5326 5556341 951BE302-C0BF-4AA3-AE12-BBAC4EDEBAFB Kasagia sudhakari Padate, Manjebrayakath & Ng, 2019 ( Figures 1E , 15D, E , 16D, E , 17C, D , 19 , 20D, E ) Kasagia sudhakari Padate, Manjebrayakath & Ng, 2019: 291–295 , figs. 2A–G, 3A–D, 4. Material examined. 1 male (cl 8.7 mm , pcl 7.0 mm, cw 5.6 mm , bcw 5.1 mm ), 1 ovigerous female (cl 8.1 mm , pcl 6.5 mm , cw 5.2 mm , bcw 4.9 mm ) (MNHN-IU-2017-8791), stn CP3131, Mozambique Channel , 2554’S 3359’E, 193–194 m , coll. MAINBAZA, 9 April 2009 . FIGURE 19. Kasagia sudhakari Padate, Manjebrayakath & Ng, 2019 , male (cl 8.7 mm, cw 5.6 mm) (MNHN-IU-2017-8791). A, dorsal view of anterior half of carapace; B, ventral view showing antennules, antennae, epistome and buccal cavity; C, right third maxilliped; D, right fourth ambulatory leg (partially denuded); E, pleon. Diagnosis. Postfrontal region relatively short ( Fig. 16D, E ); granules on posterior dorsal half of carapace closely packed ( Fig. 16D, E ). Base of pseudorostral spines separated from supraorbital eave by distinct gap ( Fig. 16D, E ). Supraocular eave eave relatively less raised, less strongly carinate, separated from pseudorostral spine by a distinct cleft ( Fig. 16D, E ). Hepatic spine triangular, distinctly dentiform, slightly larger than postocular spine, directed outwards ( Fig. 16D, E ); branchial margin of carapace with 4 short acuminate spines, even in adults ( Fig. 16D, E ). Basal antennal article enlarged proximally, forming broad triangular tooth basally, with deep median longitudinal groove, margins carinate but not strongly raised ( Figs. 17D , 19B ). Epistome forming 3 lobes. Buccal cavity wider anteriorly; ischium of third maxilliped with longitudinal row of small granules ( Figs. 17D , 19C ). Anterior part of the male thoracic sternum wide, smooth. Male pleon narrow, with long triangular telson. Chelipeds long, spiny; merus longer than carapace with large spines on each margin; carpus long with distal spine, distal part wider; chela long with up to 5 spines on outer border ( Fig. 15D ); fingers long slender. Ambulatory legs short, with dorsal margin of merus carinate, with small spinules in smaller specimens. G1 gently curved to almost straight ( Fig. 20D, E ). Type locality. Arabian Sea , off Cape Comorin , India . FIGURE 20. A–C, I, Kasagia elegans ( Stebbing, 1921 ) comb. nov. , neotype male (cl 11.8 mm, cw 7.9 mm) (MNHN-IU-2008- 10340); D, E, J, K. sudhakari Padate, Manjebrayakath & Ng, 2019 , male (cl 8.7 mm, cw 5.6 mm) (MNHN-IU-2017-8791); F–H, K. arbastoi Richer de Forges & Ng, 2007 , male (cl 13.4 mm, cw 8.0 mm) (ZRC 2014.364), Philippines. A, D, F, left G1 (ventral view); B, E, G, left G1 (dorsal view); C, H, left G2; I, J, right P5 propodus and dactylus (denuded). Scale bars = 0.5 mm. Remarks. Kasagia sudhakari , from the western Indian Ocean, can be distinguished from K. elegans comb. nov. in having the supraorbital eave relatively less raised and carinate ( Fig. 16D, E ) (versus distinctly more swollen and carinate in K. elegans comb. nov. , Fig. 16A–C ); the hepatic spine being distinctly dentiform ( Fig. 16D, E ) (versus auriculiform and lobiform in K. elegans , Fig. 16A–C ); the lateral branchial spines are acuminate even in adults ( Fig. 16D, E ; Padate et al . 2019 : fig. 2B) (versus fungiform in adult K. elegans comb. nov. , Fig. 16D, E ); and the G1 is gently curved to almost straight ( Fig. 20D, E ; Padate et al . 2019 : fig. 3A, B) (versus more sinuous in K. elegans comb. nov. , Fig. 20A, B ). In the above characters, K. elegans comb. nov. is actually morphologically closer to K. arbastoi from the Philippines , but in the latter species, the supraorbital eave is even more prominently raised, with the distal part appressed against the base of the pseudorostral spine ( Fig. 16F ; Padate et al . 2019 : fig. 5A, B) (versus less raised, separated from pseudorostral spine by a distinct gap in K. elegans comb. nov. , Fig. 16A–C ), the postfrontal region is relatively longer ( Fig. 16F ; Padate et al . 2019 : fig. 5A, B) (versus relatively shorter in K. elegans comb. nov. , Fig. 16A–C ), and the granules on the posterior dorsal half of the carapace are more widely spaced ( Fig. 16F ; Padate et al . 2019 : fig. 5A, B) (versus granules closely packed in K. elegans comb. nov. , Fig. 16A–C ).