Salaciinae 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 : 117-118

Subfamily Salaciinae Dana, 1851

Salacinae [sic] Dana, 1851: 430; 1852: 75–78, 81.— Brito Capello 1871: 264.

Salacini [sic] Števčić 2005: 99.

Salaciinae Guinot 1984: 381 .— Guinot & Cleva 2002b: 508.— Guinot 2012: 30.

Salaciini Števčić 2013: 185.

Type genus. Leurocyclus Rathbun, 1897 , Salacia H. Milne Edwards & Lucas, 1842 being preoccupied by Salacia Lamouroux, 1816 , a hydrozoan, and replaced by Leurocyclus ( Rathbun 1897) [(type species: L. tuberculosus (H. Milne Edwards & Lucas, 1842) ]. See also Miers (1879). Although Salacia is not a valid nomen, the subfamily Salaciinae Dana, 1851 ( Salacinae is an incorrect spelling of the nomen) is an available nomen that was used by Dana (1851: 430), with Leurocyclus as type genus (see Drach & Guinot 1983: figs. 6–9; Guinot 1984: fig. 1; Guinot & Richer de Forges 1997: fig. 12B; Guinot & Cleva 2002a: 40; 2002b: 508; Santana 2008: figs. 45C, D, 47B, C, 48A; Guinot et al. 2013: fig. 47I). An unfortunate typographical mistake in (2012) Guinot’s abstract attributed the authorhip of the family to H. Milne Edwards & Lucas, 1842, instead of Dana, 1851.

Description. Carapace much broader than long, suborbicular, depressed, dilated posterolaterally (H. Milne Edwards & Lucas 1842: pl. 2, fig. 1, as Salacia ; Rathbun 1925: pl. 233, fig. 1; Drach & Guinot 1983: pl. 1, fig. 6; Guinot 1984: fig. 1; Melo 1996: fig. p. 207; Guinot & Richer de Forges 1997: fig. 12B). Carapace resting on setting gutter. Dorsal surface with longitudinal carina marked by granules; regions well marked by deep grooves and ornamented ( Santana 2008: figs. 45C, D, 47C). Rostrum small, narrow, subtriangular. Proepistome laterally compressed, reduced to recessed, concealed portion, not joining anterior process (a narrow septum) of rudimentary epistome ( Rathbun 1925: pl. 232, fig. 6). Antennulae: both vertically folded in two fossae, without visible separation, the latter being deeply recessed. Antenna: urinary article and basal article adjacent, seemingly fused; basal article (2+3) very wide, concave, without longitudinal carina, with lateroexternal lobe (H. Milne Edwards & Lucas 1842: pl. 2, fig. 2, as Salacia ; Rathbun 1925: pl. 232, fig. 11; Guinot 1984: fig. 2; Santana 2008: fig. 48A); following articles (antennal movable portion) entirely visible in dorsal view at side of rostrum. Orbits rather large, directed forward, close to each other; preorbital tooth absent; postorbital tooth large forming postocular cup (supraocular eave) accommodating eyestalk in resting position ( Santana 2008: fig. 48A). Mxp3: ischium broad, with developed crista dentata formed by strong spines; merus cordiform (H. Milne Edwards & Lucas 1842: pl. 2, fig. 5, as Salacia ; Rathbun 1925: pl. 232, figs. 8, 10). Pleurites regularly connecting medially and fused to carapace by pillars ( Drach & Guinot 1983: pl. 1, figs. 7, 8). Thoracic sternum: lateral suture 3/4 short, ending as perforation of the sternal surface ( Rathbun 1925: pl. 233, fig. 2); sutures 4/5–7/8 interrupted; a bridge at base of sternite 8, then median line extending on sternite 8. Sternite 3 forming a narrow, short extension; no sternum/pterygostome junction at level of sternite 4 (H. Milne Edwards & Lucas 1842: pl. 2, fig. 8, as Salacia ; Guinot 1979: pl. 16, figs. 5, 6; Santana 2008: fig. 47D). Milne-Edwards openings not separated from chelipeds. Sternal extensions joining exposed pleurites (sternum/pleurites connections) between pereiopods. Pleurites 5–8 exposed but proportionally small and narrow, each pointed at each end (thus collar with festooned appearance), ornamented ( Drach & Guinot 1983: pl. 1, fig. 6; Guinot 1984: fig. 1; Santana 2008: fig. 47B, C). Male chelipeds very short; palm swollen; fingers long, slightly curved, inner margins denticulate ( Rathbun 1925: pl. 232, fig. 9; Santana 2008: fig. 47A, B). Ambulatory legs very long, spinulous; merus subcylindrical; propodus compressed; dactylus long, slender, compressed, slightly curved ( Rathbun 1925: pls. 82, 83, pl. 233, fig. 1; Guinot 1984: figs. 3, 4; Santana 2008: fig. 47B). Pleon: only first somite dorsal, well developed. Male pleon with somites 1–5 free, somite 6 being fused to telson (pleotelson); female pleon with somites 1–4 free, somites 5, 6 being fused to telson (pleotelson). Male gonopore partially condylar, partially coxal ( Guinot et al. 2013: 127, fig. 31C). G1 as straight, simple plate, with apical aperture (Garth 1968: pl. T, fig. 9). Vulvae located on anteriorly displaced on sternite 6, not projecting on sternite 5. Penis emerging from coxo-sternal condyle’s extremity.

Other included genera. None.

Remarks. H. Milne Edwards & Lucas (1842: pl. 2, figs. 1–8; 1843: 12, as Salacia tuberculosa ) based the species on three specimens collected by A. d’Orbigny (see Guinot & Cleva 2002a, 2002b) and diagnosed it by a practically circular carapace and a short, narrow rostrum. Both nomina Salacia and Salacinae were used by Brito Capello (1871: 263, 264, pl. 3, fig. 3, 3a), then not used for a long time.

An unconstrained analysis of larval characters of Leurocyclus tuberculosus suggested that it was the most basal taxon of Inachidae + Inachoididae ( Marques & Pohle 2003: 76, figs. 1A, 2). The larval morphology of L. tuberculosus conforms to the general pattern found in Majoidea , but the two zoeal stages and the megalopa differs from those of all known inachoidids by a series of characters ( Marques & Pohle 2003; Santana & Marques 2009). All this supports the separation of the genus in its own subfamily. Leurocyclus tuberculosus , as other inachoidids, is a determinate growth crab, but growth patterns differ beween the sexes ( MacLay 2015).

The biology of Leurocyclus granulosus is well studied ( Barón et al. 2009; Stauffer et al. 2011; González-Pisani et al. 2011, 2017). According to González-Pisani et al. (2017), the integrated analysis of size at maturity and size frequency distributions showed that in both sexes molt to gonadal, morphological, morphometric, and functional sexual maturity occurred in advance of the terminal molt, in contrast with patterns observed in other Majoidea .