The genus Trichorhina Budde-Lund, 1908 (Crustacea, Isopoda, Platyarthridae) in the Ibero-Balearic region, with descriptions of three new species

The genus Trichorhina, belonging to the family Platyarthridae, has mostly a tropical distribution. Nonetheless, the Ibero-Balearic region currently hosts seven species, including four previously known species (T. anophthalma, T. buchnerorum, T. hispana and T. silvestrii) and three species described in this study (T. cascaisensis sp. nov., T. ornata sp. nov. and T. solorzanoi sp. nov.). Trichorhina cascaisensis sp. nov. is characterized by a dorsal integument with granulations arranged in several longitudinal lines and with large scale-setae, noduli laterales successively closer to the lateral and posterior edges of the pereonites, cephalon not inserted in the pereon, pereonites posterior corners convex, pleon not retracted in relation to pereon, and a triangular telson with an obtuse tip.

Trichorhina ornata sp. nov. is characterized by a smooth dorsal integument with large scale-setae arranged in longitudinal lines, high values of the noduli laterales d/c coordinates, pereonites posterior corner weakly sinuous, pleon not retracted in relation to pereon, and a sub-triangular telson with a widely rounded posterior edge. Trichorhina solorzanoi sp. nov. is characterized by a smooth dorsal integument, pleon not retracted in relation to pereon, large and falciform neopleura, a triangular telson with a rounded tip, pleopod exopod I subtrapezoidal in males, and has a large distal part in females.

To facilitate identification, new descriptions of T. anophthalma and T. silvestrii are provided, accompanied by new figures of these species, as well as a dichotomous key for the Trichorhina species in the Ibero-Balearic region.