Seiitaoides kabuto, Forges & Lee & Ng, 2021

Forges, Bertrand Richer De, Lee, Bee Yan & Ng, Peter K. L., 2021, The taxonomy of spider crabs of the genera Eurynome, Choniognathus, Seiitaiodes and Kasagia (Crustacea: Brachyura: Majidae) from southwest Indian Ocean, Zootaxa 5048 (3), pp. 301-333 : 317-319

publication ID	https://doi.org/ 10.11646/zootaxa.5048.3.1
publication LSID	lsid:zoobank.org:pub:951BE302-C0BF-4AA3-AE12-BBAC4EDEBAFB
DOI	https://doi.org/10.5281/zenodo.5569410
persistent identifier	https://treatment.plazi.org/id/03B187B7-FF8C-FFA1-89B3-A453FEBE5A2F
treatment provided by	Plazi
scientific name	Seiitaoides kabuto
status	sp. nov.

Treatment

Seiitaoides kabuto View in CoL n. sp.

( Figures 10A–D View FIGURE 10 ; 11A–E View FIGURE 11 )

Material examined. Holotype: ovigerous female (cl 10.0 mm, pcl 8.6 m, cw 5.3 mm, bcw 4.5 mm) (MNHN-IU-2016-7089), stn DW4836, Comoros Islands , 1225’S 4356’E, 82–88 m, coll. BIOMAGLO, 28 January 2017 . Paratype: 1 female (cl 11.2 mm, pcl 9.3 mm, cw 5.7 mm, bcw 5.1 mm) (MNHN-IU-2016-7090), 1 ovigerous female (cl 10.1 mm, pcl 8.6 mm, cw 5.3 mm, bcw 4.6 mm) ( ZRC 2020.377 View Materials , ex MNHN-IU-2016-7088), same locality and collection data as holotype .

Diagnosis. Pseudorostral spines short, subcylindrical, gently diverging; outer margin with 2 accessory spines ( Fig. 10B, D View FIGURE 10 ). Supraocular eave wide, margin entire, proximal part with low, blunt preocular tooth; partially overlaps long sharp flattened postocular spine; intercalated spine short, tightly appressed against eave and postocular spine; no obvious gaps between spines ( Fig. 10B, C View FIGURE 10 ). Hepatic spine well developed, lobiform, sharp, directed outwards, with distinct boletiform tubercle dorsal to it, separated from postocular spine by wide gap ( Fig. 10B, C View FIGURE 10 ). Gastric region well defined bearing several plates and granules; median part with 2 large circular plates arranged longitudinally, appressed against each other; protogastric region with 2 small round plates, laterally appressed; cardiac region raised, with 2 large lateral plates fused medially; branchial region with 3 closely arranged plates ( Fig. 10B, D View FIGURE 10 ; Fig. 11A View FIGURE 11 ). Intestinal region, posterior carapace margin and posterolateral margin forming 1 broad brace-like granuliform plate, vaguely divided into 3 parts ( Fig. 10B, D View FIGURE 10 ). Epistome quadrate ( Fig. 11B View FIGURE 11 ). Third maxilliped with ischium distinctly tuberculated ( Fig. 11C View FIGURE 11 ). Female cheliped short; merus, carpus and chela spiny ( Fig. 11D View FIGURE 11 ). Ambulatory legs short, with merus and propodus spiny ( Figs. 10A, C View FIGURE 10 , 11E View FIGURE 11 ). Female pleonal somite 1 with large rounded tubercle covered with small granules ( Fig. 10B, D View FIGURE 10 ).

Type locality. Comoros Islands .

Etymology. The name alludes to the general appearance of the carapace, superficially resembling a kabuto, the Japanese name for a samurai helmet. The name is used as a Latin noun in apposition.

Remarks. Seiitaioides kabuto n. sp. is morphologically most similar to S. stimpsoni ( Miers, 1884, but differs in the pseudorostral spines being slender, with two accessory spinules on the outer margin ( Fig. 10C, D View FIGURE 10 ) (versus prominently dorsoventrally flattened with margins unarmed in S. stimpsoni ; Fig. 12A View FIGURE 12 ; Miers 1884: pl. 47 fig. A); having both median gastric plates subequal in size ( Fig. 10B, D View FIGURE 10 ) (versus posterior plate distinctly smaller in S. stimpsoni ; Fig. 12A View FIGURE 12 ; Miers 1884: pl. 47 fig. A); the supraorbital eave is long and slopes anteriorly towards the front ( Fig. 10B, D View FIGURE 10 ) (versus short and subparallel in S. stimpsoni ; Fig. 12A View FIGURE 12 ; Miers 1884: pl. 47 fig. A); the hepatic region has a small dorsal boletiform tubercle and a large lobiform spine ventral to it ( Fig. 10B, D View FIGURE 10 ) (versus with only large dorsal boletiform tubercle in S. stimpsoni ; Fig. 12A View FIGURE 12 ; Miers 1884: pl. 47 fig. A); and the lateral branchial plates are proportionately much larger ( Fig. 10B, D View FIGURE 10 ) (versus small in S. stimpsoni ; Fig. 12A View FIGURE 12 ; Miers 1884: pl. 47 fig. A).

The description and figure of S. stimpsoni by Miers (1884: 523, pl. 47 fig. A) does not show an intercalated spine but it is probably present. In S. kabuto n. sp., the intercalated spine is small and tightly appressed against the supraocular eave and postocular spine with no gaps between them ( Fig. 10B, C View FIGURE 10 ), so much so that the structures appear almost completely fused. It could thus have been easily missed by Miers.

Seiitaioides kabuto n. sp. also resembles S. mirabilis n. sp., with both having large boletiform plates covered by granules. In S. kabuto n. sp., however, the hepatic tooth is long flattened and sharp ( Fig. 10B, D View FIGURE 10 ) (versus short and thinner in S. mirabilis n. sp.; Fig. 8B View FIGURE 8 ); the preocular tooth is overlapping the wide postocular tooth, closing the gap and leaving only a very reduced intercalated spine ( Fig. 10B, D View FIGURE 10 ) (versus a long blunt postocular tooth not touching the preocular tooth in S. mirabilis n. sp.; Fig. 8B View FIGURE 8 ); there is two partially fused plates ( Fig. 10B, D View FIGURE 10 ) (versus only one large cardiac plate in S. mirabilis n. sp.; Fig. 7B View FIGURE 7 ); there are two large gastric plates ( Fig. 10B, D View FIGURE 10 ) (versus only one cardiform plate in S. mirabilis n. sp.; Fig. 7B View FIGURE 7 ); the epistome is squarish ( Fig. 11B View FIGURE 11 ) (versus longer than wide in S. mirabilis n. sp.; Fig. 9A, B View FIGURE 9 ); and the ambulatory legs are spiny ( Fig. 10A View FIGURE 10 , 11E View FIGURE 11 ) (versus smooth in S. mirabilis n. sp.; Fig. 8A View FIGURE 8 , 9D View FIGURE 9 ).