First record and a new species of Euphrosynoplax (Crustacea: Pseudorhombilidae) from the southwestern Atlantic

. A new species of deep-water brachyuran crab, Euphrosynoplax dincao, from southeastern Brazil is described and illustrated. The genus Euphrosynoplax currently consists of two species, E. clausa Guinot, 1969, and E. campechiensis Vázquez-Bader & Gracia, 1991, both only known from the Gulf of Mexico. The new species can be easily separated from its northern counterparts by a suite of carapace and appendage characters. Euphrosynoplax campechiensis is recorded for the first time from the Caribbenan Sea (Guadeloupe and between Saint Kitts and Nevis).


INTRODUCTION
Euphrosynoplax Guinot, 1969, was established as a monotypic genus for E. clausa Guinot, 1969, from Dry Tortugas, Gulf coast of Florida. More than two decades elapsed before a second species of the genus was described, namely E. campechiensis Vázquez-Bader & Gracia, 1991, also from the Gulf of Mexico. The genus currently consists of the above mentioned two species, both only known from the Gulf coasts (Vázquez-Bader & Gracia, 1991;Ng et al., 2008;Felder et al., 2009).
Euphrosynoplax is now expanded to encompass a new species from much farther south, off the coast of southeastern Brazil. The new species is the first record of Euphrosynoplax from the southwestern Atlantic Ocean.

MATERIAL AND METHODS
The studied specimens are deposited either in the collections of the MZUSP (Museu de Zoologia, Universidade de São Paulo, Brazil) or USNM (National Museum of Natural History, Smithsonian Institution, Washington D.C.). Abbreviations used include: carapace length (cl), taken from the front to the posterior margin of the carapace; carapace width (cw), taken at the level of the third anterolateral tooth of the carapace; P1 cheliped; P2-P5, pereiopods 2 to 5; G1, G2, first and second gono-pod, respectively; stn, station; coll., collected by; F/V, fishing vessel; R/V, research vessel; don., donated by. Dates are written in the format day.month. year, with months in lower-case Roman numerals.
Antennules prominent; basal article thickest laterally, with transverse row of coarse granules; second article smooth, elongate, subcylindrical, articulated to basal article at mesial end of antennular fossa; third article nearly equal in length to second, swollen distally, tapered to proximal articulation with second article, terminally with long stiff setae.
Chelipeds heterochelous (Fig. 1D, E), left P1 strongest. Merus of major P1 trigonal, dorsal margin with row of spiny tubercles; lateral and ventral surfaces evenly covered with minute granules, and few scattered larger tubercles. Carpus with strong, blunt spine on inner margin; surfaces coarsely tubercular, tubercles of different sizes, spiny. Propodus stout, surfaces minutely granular. Fingers massive, gently curved inward, closing terminally only; cutting edges bluntly dentate, teeth of different sizes. Minor cheliped similar to major cheliped except for its less sout propodus and slender fingers.
Female paratype resembling male, although much smaller. Pleon of 6 free, narrow pleonites and telson. Pleonites 1 to 5 of about same width and length; sixth pleonite almost twice as long previous pleonites. The paratype female carried numerous small eggs.

Etymology:
We take great pleasure in naming this new species after our esteemed colleague and friend Fernando D'Incao (1947-2016, carcinologist and oceanographer at Universidade Federal do Rio Grande, Brazil. The specific name is used as a name in apposition.
Euphrosynoplax campechiensis is herein recorded for the first time from the Caribbean Sea (Guadeloupe and between Saint Kitts and Nevis-see above under material examined).
Euphrosynoplax dincao sp. nov. (Fig. 1A-E; 2A, B; 3A, D, F) can be easily distinguished from the above two species in that the distal end of the male P5 merus falls short of the last (fourth) anterolateral carapace tooth or reaches to the base of the tooth at most, whereas in the northern counterparts the distal end of the male P5 merus extends almost to the tip of the last anterolateral carapace tooth ( Fig. 2A-F). The three species also differ in the shape of the mesial lobe and development of the apical lobe of the G1 (Fig. 3A-E).
The new species is morphologically closer to E. campechiensis (Fig. 2C, D; 3B, E; 4A-D) of which it further differs in having the anterolateral teeth and anterolateral, pterygostomial and branchiostegal regions much more densely and coarsely tuberculated; the carapace front prominently protruded in ventral view (vs front distinctly less protruded in ventral view in E. campechiensis); and the area behind the supraorbital margin distinctly granular, devoid of tiny pubescence (vs area behind the supraorbital margin devoid of granules and with tiny pubescence in E. campechiensis). Euphrosynoplax dincao sp. nov. additionally stands apart from E. clausa (Fig. 2E-F; 3C; 5A-D) in having the carapace and appendages unevenly tubercular with tubercles of different sizes (vs carapace and appendages more evenly and finely granular); carapace regions well marked (vs carapace regions faintly marked in E. clausa); last (fourth) anterolateral tooth large and more laterally directed (vs last carapace tooth much smaller and more forward directed in E. clausa); orbits, almost completely filled by the ocular peduncle, orbital cavity smooth (vs orbits distinctly larger than the ocular peduncle, upper region inside the orbital cavity granular in E. clausa); and the frontal margin, bilobed, V-shaped incised, each lobe with a lateral prominence (vs frontal margin much less prominent, U-shaped incised, each lobe only gently prominent laterally in E. clausa).
The north-south disjunct distribution pattern of Euphrosynoplax is highly comparable to those of other moderately deep-water decapods, such as Eumunida, Neopilumnoplax, Robertsella, Speocarcinus and Trichopeltarion (Brandão et al., 2010(Brandão et al., , 2012Tavares & Melo 2005Tavares & Gouvea, 2013;Tavares & Lima 2019). Such distribution gaps may well be only the result of poor distributional information and detectability, as exemplified by the deep-water genus Chaceon, whose fragmented distribution of some of its southwestern Atlantic representatives has been slowly filled as a result of the intensification of deep-water commercial fishing and detection facilitated by the species' large size (Manning & Holthuis, 1989;Tavares & Pinheiro, 2011).