Paulitinae Guinot & Van Bakel

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 : 115-116

Subfamily Paulitinae Guinot & Van Bakel , subfam. nov.

Type genus. Paulita Guinot, 2012 (type species by monotypy: Dasygyius tuberculatus Lemos de Castro, 1949 ).

Description. Body moderately flat. Carapace urn-shaped, with moderate anterior narrowing, resting on setting gutter ( Lemos de Castro 1949: figs. 8, 9, as Dasygyius tuberculatus ; Drach & Guinot 1982: pl. 1, fig. 1, as Paradasygyius tuberculatus ; Santana 2008: figs. 50C, 51B, C, as Paradasygyius tuberculatus ; Guinot 2012: figs. 1, 2A; Guinot et al. 2019: fig. 16A). Dorsal surface ( Guinot 2012: figs. 1, 2A, B) divided into convex regions delineated by several parallel, deep, broad grooves: cervical groove well marked, bearing median gastric pits; branchial groove delimiting main part of branchial region; branchiocardiac groove marked. Dorsal surface uniformly covered with prominent tubercles. Lateral margins rounded, unarmed. Pleurites 5–8 ( Guinot 2012: fig. 2A, B) exposed on same level as carapace, calcified, ornamented as carapace; first pleonal somite in prolongation of cephalothorax, dorsally visible, calcified, ornamented; insertion of carapace into setting gutter ( Drach & Guinot 1982: pl. 1, fig. 3, as Paradasygyius tuberculatus ); branchiostegite mostly absent. Rostrum simple, broadly triangular, pentagonal ( Lemos de Castro 1949: fig. 4, as Dasygyius tuberculatus ), its ventral portion (proepistome) joining the epistomial process. Antennules vertically folded beneath rostrum. Eyestalk narrow. Antenna: urinary article adjacent to basal article (2+3) (thus not sunken in epistome); basal article large, fused to front, unarmed; articles 4, 5 free; flagellum short ( Lemos de Castro 1949: fig. 5, as Dasygyius tuberculatus ). Supraorbital margin with median tooth. Exorbital tooth blunt. Pterygostomial lobe well marked ( Guinot 2012: fig. 3B). Mxp3: ischium with inner margin coarsely dentate, produced into lobe at inner distal angle; merus cordiform, with outer angle slightly rounded laterally and inner angle produced; palp stocky, with carpus enlarged, three-fifths as thick as long ( Lemos de Castro 1949: fig. 3, as Dasygyius tuberculatus ; Guinot 2012: fig. 3B). Thoracic sternum markedly wide, inflated; anterior shield (sternites 1–3) inserted between mxp3, as a pentagonal shield; sternite 3 developed, much inflated; suture 3/4 laterally visible, continuing into depression ( Santana 2008: figs. 51D, 52B, as Paradasygyius tuberculatus ; Guinot 2012: figs. 2C, 3A; Guinot et al. 2019: fig. 16C). Sutures 4/5–7/8 all interrupted, with distant interruption points. Sternite 8 with basal median line, continuing by depression. Sternum/pterygostome junction complete thanks to curved extension of sternite 4. Milne-Edwards openings separated from chelipeds, large, entirely filled by mxp3 coxa ( Guinot 2012: fig. 3B). Wide sternal extensions joining exposed pleurites (sternum/pleurites connections) between P1/P2, P2/P3, P3/P4, P4/P5 ( Guinot 2012: figs. 2C, 3A). Sternal device for pleonal-locking system represented by 2 or several granules disposed between sutures 4/5, 5/6; pleonal edge of somites 4–6 markedly thickened, ending in deep socket. Male, female pleons with first somite developed, entirely dorsally visible, ornamented like carapace, not produced into spine. Male pleon ( Lemos de Castro 1949: fig. 6, as Dasygyius tuberculatus ; Guinot 2012: figs. 2C, 3A) with all somites free, except for somite 6 fused to telson (pleotelson); somite 1 narrow but high; somites 2, 3 widened; somites 4, 5, pleotelson narrow; pleotelson base laterally inflated at location of sockets. Female pleon ( Lemos de Castro 1949: fig. 7, as Dasygyius tuberculatus ; Guinot 2012: fig. 2D) with somites 1–4 free, not high; somites 5, 6 fused to pleotelson, forming large, flat or convex disc, inserted in sterno-pleonal cavity; brood cavity closed like a box, limited by elevated sternal arch formed by raised sternites all around. Male chelipeds ( Lemos de Castro 1949: fig. 2, as Dasygyius tuberculatus ; Guinot 2012: fig. 1) equal, unarmed, with minute granules; propodus narrow, elongated, slightly inflated in larger males; fingers long, tapering, gaping in proximal half, distally joined; prehensile border finely denticulated in proximal half, distinctly toothed distally. Female chelipeds ( Lemos de Castro 1949: fig. 1, as Dasygyius tuberculatus ; Guinot 2012: fig. 2D) narrow, fingers joined. Pereopods long, thin, cylindrical throughout length, unarmed; P2 densely fringed with hairs in males; P2-P5 with additional setae in females ( Lemos de Castro 1949: figs. 8–11 as Dasygyius tuberculatus ; Guinot 2012: fig. 1). Coxal male gonopore large, located far from suture 7/8, thus in posteriormost location; opening on anterior border of coxo-sternal condyle, thus partially condylar, partially coxal ( Guinot et al. 2013: 127); penis short, emerging on lateral side of coxo-sternal condyle. G1 gently curved, with elongated, twisted lobe ( Guinot-Dumortier 1960: fig. 22a–c, as Paradasygyius tuberculatus ; Santana 2008: figs. 50C, 51D, as Paradasygyius tuberculatus ). G2 conspicuously short. Vulvae much protruded, located on sternite 6 displaced anteriorly to suture 4/5; sternal vulvar cover developed. Axial skeleton with lateral compartment together with dorsoventral partition (developed junction plate), pleurites being almost horizontal ( Guinot 2012: fig. 2B); in anterior region, dorsal edges of pleurites connected to internal surface of carapace by vertical pillars ( Drach & Guinot 1982: pl. 1, fig. 6, as Paradasygyius tuberculatus ). A bridge with median line (with posteriorly and anteriorly a depression) in middle of sternite 7 (corresponding to raised median plate). Presence of thick sella turcica ( Guinot et al. 2013: fig. 47G, H).

Remarks. Paulitinae subfam. nov. may be differentiated from the Dasygyiinae by a number of characters mainly related to the carapace, thoracic sternum, links between sternum and pterygostome, Milne-Edwards openings, and first gonopod.

Other included genera. None.