Apograpsus, Komai & Wada, 2008

Komai, Tomoyuki & Wada, Keiji, 2008, A Revision Of The Estuarine Crab Genus Ilyograpsus Barnard, 1955 (Crustacea: Decapoda: Brachyura: Macrophthalmidae), With Descriptions Of A New Genus And One New Species, Raffles Bulletin of Zoology 56 (2), pp. 357-384 : 380

Key to species of Ilyograpsus and Apograpsus , new genus

1. Carapace longer than broad, with 3 anterolateral teeth (including external orbital tooth) of which second tooth poorly developed; postfrontal ridges longitudinal, each with peculiar long setae anteriorly ................... Apograpsus paantu , new combination

– Carapace wider than long, with 4 conspicuous anterolateral teeth (including external orbital tooth); postfrontal ridges transverse or L-shaped, without long setae ..................... 2 ( Ilyograpsus )

2. Regions of carapace poorly defined, lacking epigastric ridges or tubercles ............................................................................ 3

– Regions of carapace markedly defined, bearing epigastric ridges or tubercles ............................................................................ 4

3. Second and third anterolateral teeth moderately large, anterolateral margin generally convex; male first gonopod with elongate terminal process ................ Ilyograpsus rhizophorae

– Second and third anterolateral teeth small, anterolateral margin nearly parallel; male unknown ................................ I. vannini

4. Merus of cheliped with conspicuous subdistal spine; proportional length of dactylus of fourth pereopod (length of dactylus / length of propodus) included in range of 0.60–0.90; terminal process of male first gonopod somewhat elongate ............................ 5 Remarks. – Like species of Ilyograpsus , Apograpsus paantu shows notable sexual dimorphism in some characters. For example, the external orbital teeth are more strongly projecting in males than in females (cf. Figs. 17A and 18A ); the ocular peduncles is relatively larger in males than in females (cf. Figs. 17A and 18A ); the front is more distinctly bilobed in males than in females (cf. Figs. 17A and 18A ); the ambulatory legs are shorter in females than in males (cf. Fig. 16A and 16B ). On the other hand, the structure of the lower orbital margin is similar between males and females.

Figures

Fig. 17. Apograpsus paantu (Naruse & Kishino, 2006), new combination. A–E, H, I, male (cl 3.9 mm), CBM-ZC 8834, Yagaji Port, Yagaji Island, Okinawa Islands, Japan. F, G, male (cl 3.4 mm), paratype, RUMF-ZC-238, Tima River estuary, Nago, Okinawa Island. A, carapace, ocular peduncles, and antennae, dorsal view (setae partially omitted); B, cephalothorax and cephalic appendages, frontal view; C, right lower orbital margin, ventral view; D, pleon, ventral view; E, left third maxilliped, ventral view; F, left fourth pereopod, dorsal view; G, left fifth pereopod, dorsal view; H, left first gonopod, ventral view; I, same, distal part, dorsal view. Scale bars: A, B, D = 1 mm; E–I = 0.5 mm.

Fig. 18. Apograpsus paantu (Naruse & Kishino, 2006), new combination. Female (cl 6.4 mm), paratype, CBM-ZC 8493, Yanma, Sumiyo, Amami-ohshima Island, Japan. A, carapace, ocular peduncles and antennae, dorsal view; B, merus of left cheliped, outer view; C, chela and carpus of left cheliped, dorsal view; D, left chela, outer view; E, left fourth pereopod, dorsal view; F, left fifth pereopod, dorsal view. Scale bars: A = 2 mm; B–F = 1 mm.

Fig. 16. Apograpsus paantu (Naruse & Kishino, 2006), new combination.A, male (cl 3.4 mm), RUMF-ZC-238, paratype, Tima River estuary, Nago, Okinawa Island, Japan; B, female (cl 6.4 mm), paratype, CBM-ZC 8493, Yanma, Sumiyo, Amami-ohshima Island, Japan.