Inachoidinae Dana, 1851

Guinot, Danièle & Bakel, Barry Van, 2020, Extraordinary majoid crabs: the genus Esopus A. Milne-Edwards, 1875 in the new subfamily Esopinae subfam. nov., and erection of Paulitinae subfam. nov. (Crustacea, Decapoda, Brachyura, Majoidea, Inachoididae Dana, 1851), Zootaxa 4766 (1), pp. 101-127 : 115

Subfamily Inachoidinae Dana, 1851

Inachoidini Števčić, 2005: 99; 2013: 185.

Type genus. Inachoides H. Milne Edwards & Lucas, 1842 (type species by monotypy: I. microrhynchus H. Milne Edwards & Lucas, 1842 ; junior synonym: Inachoides lambriformis De Haan, 1839 , see Holthuis 1993 ( Drach & Guinot 1983: fig. 4, as Inachoides microrhynchus ; Guinot & Cleva 2002b: 507; Santana 2008: figs. 45B, 46A; Santana & Tavares 2009: figs. 1E, F, 2D). Other spcies: Inachoides laevis Stimpson, 1860 ( Hendrickx 1999: figs. 38, 39; Santana 2008: figs. 44A, 45A); Inachoides forceps A. Milne-Edwards, 1879 (junior synonym: Podochela meloi Sankarankutty, Ferreira & Cunha, 2001) ( Williams 1984: figs. 234, 240; Melo 1996: fig. p. 206; Coelho 2006: 678; Santana & Tavares 2009: 62–68, figs. 1A–D, 2A–C).

Description. Carapace longer than wide, triangular, broad and swollen behind, anteriorly narrowing, with marked depression between orbits. Carapace resting on setting gutter. Dorsal surface with tubercles and granules, or nearly smooth except for cardiac tubercle; some inflated regions ( Rathbun 1925: pl. 22, fig. 1, as Inachoides microrhynchus ; Drach & Guinot 1983: pl. 1, fig. 1, as Inachoides microrhynchus ; Garth 1958: pl. 6, fig. 3, as Inachoides microrhynchus ; Santana 2008: figs. 44A, 45A, B, 46A; Santana & Tavares 2009: fig. 2: I. forceps and I. lambriformis ). Rostrum simple, short, ending in spine. Preorbital tooth absent ( Hendrickx 1999: fig. 38B: I. laevis ). Postorbital tooth minute or strong. Orbits entire. Antenna: articles 1, 2+3 fused to epistome, urinary orifice sunken in epistome; basal article narrow, with low carina or only granular rows; anteroexternal tooth exposed in dorsal view; flagellum exposed from its insertion. Proepistome long, laterally compressed, not joining (small gap) advanced process of epistome. Epistome large, nearly quadrilateral. Mxp3: merus as wide as ischium, rounded at anteroexternal angle ( Rathbun 1925: fig. 16); crista dentata indistinct. Thoracic sternum flat, except first three inflated sternites ( Santana 2008: fig. 46B). Sternum/pterygostome junction apparently complete, sternite 4 extending by thin terminal process; lateral suture 3/4 short, ending by deep depression; Milne-Edwards openings separated from chelipeds. Exposed pleurites 5–8 forming rather narrow collar, especially first two; pleurites regularly connecting medially and fused to carapace by pillars ( Drach & Guinot 1983: pl. 1, fig. 4, as Inachoides microrhynchus ). Male chelipeds strong; palm swollen; fingers narrowly gaping at base ( Rathbun 1925: pl. 22, figs. 1–6 as Inachoides microrhynchus and I. laevis ; Hendrickx 1999: fig. 38B: I. laevis ; Santana & Tavares 2009: fig. 1A, B: I. forceps ). Female chelipeds weaker than legs, palm not swollen ( Santana & Tavares 2009: fig. 1C, D: I. forceps ). Ambulatory legs of moderate length, slender, with curved dactyli ( Santana & Tavares 2009: fig. 3: I. forceps ). Pleon: first somite dorsal, produced into small spine or not. Male pleon with somites 1-5 free, somites 6 being fused to telson (pleotelson); female pleon ( Rathbun 1925: pl. 23, figs. 3, 4) with somites 1–4 free, somites 5, 6 being fused to telson (pleotelson). G1 straight; long subapical lobe with aperture; tip sharply or broadly triangular ( Garth 1958: pl. E, figs. 6, 9; Williams 1984: fig. 241i). Pleonal-locking mechanism: button on sternite 5; socket on pleotelson.

Other included genera. There may be perhaps more to be added in the future (see below, Status of other inachoidid genera).