Trichorhina tropidocerata, Souza & Araújo & Campos-Filho, 2011

Souza, L. A., Araújo, J. P. & Campos-Filho, I. S., 2011, The genus Trichorhina Budde-Lund in Brazil, with description of seven new species (Isopoda, Oniscidea, Platyarthridae), Iheringia, Série Zoologia 101 (32), pp. 239-261 : 255

Trichorhina tropidocerata sp. nov.

( Figs 7 , 108–124 )

Type material. Holotype ♂, BRAZIL, São Paulo: Santos ( Ponta da Praia ), under bricks and stones 100 m from fishing station, 27.XI.1963, P. S. Moreira col. ( MNRJ 4125 ). Paratypes: 23♂, 38♀, same data as holotype ( MNRJ 4126 ).

Diagnosis. Body pale yellow, with small brown spots in head. Eyes with 15 black ommatidia. Molar process of mandibles with seven penicils. Exite of maxillulae with eight simple teeth.

Measurements. Male, length: 3.58 mm, width: 1.33 mm; female, length: 5.04 mm, width: 1.99 mm. Description. Pigmentation of body faint, pale yellow, with small brown spots in head. Eyes black with 15 ommatidia. Pereonite Iwith anterior margins reaching the line of the eyes, and lateral lobes slightly ahead of median lobe which has apex rounded and straight sides ( Figs 109, 110 ). Pleon narrower than pereon ( Fig. 108 ), pleonites III–V with well developed epimera; telson triangular and depressed in the middle. Body surface with semi-circular scales. Pereon, pleon and telson covered with fan-shaped scale-setae and two axial rods ( Fig. 114 ). In posterior margins of pereonites they are large and wide, intercalate with small and narrow ones, and in lateral margins they are small. Nodulus lateralis with featureless base ( Fig. 115 ). Pereonite VII with only one nodulus lateralis on each side. Position of noduli laterales as illustrated ( Fig. 7 ). Projected tubercles apically in merus and carpus of pereopods II–VII ( Fig. 118 ). Antenna ( Fig. 111 ) stretched reaches half of pereonite III. Second joint of antennal peduncle with dorsal keel, projecting over third join. Second joint of antennal flagellum with distal groove. Left mandible ( Fig. 112 ) without rods between molar and incisory processes. Number of penicils in molar process of left mandibles seven ( Fig. 112 ), right seven ( Fig. 113 ). Outer group of exite of maxillulae with four teeth, one smaller. Inner group of exite of maxillulae with four simple teeth ( Fig. 116 ). Endite of maxilliped without small teeth in distal outer border; distal border irregular ( Fig. 117 ). Pleopods without respiratory areas.

Male. Pereopods I ( Fig. 119 ) and VII ( Fig. 118 ) without sexual dimorphism. Pleopod Iwith subtriangular exopod ( Fig. 120 ); endopod with distal half slightly turned to the outside, apex simple ( Fig. 121 ). Pleopod II with exopod subtriangular with rounded apex ( Fig. 123 ); endopod narrowed in second half ( Fig. 122 ). Pleopod V with subtriangular exopod ( Fig. 124 ).

Remarks. Trichorhina tropidocerata sp. nov. is distinguished from Trichorhina lobata Verhoeff, 1946 which has a similar number of ommatidia (13 to 14) by 1) second joint of antennal peduncle with a keel; 2) endite of maxilliped without teeth (with three stout teeth in T. lobata ); 3) ischium of pereopod VII of male without keel; 4) scales in pereopods II–VII. Distinguished from all other species of the genus by the eyes composed by 15 ommatidia.

Etymology. Species name comes from Greek tropis = keel and ceras = feeler, due to the strong keel in antennalpeduncle.

Figures

Figs 1–7. Ratio b/c and d/c of noduli laterales on pereonites I–VII: 1, Trichorhina biumbonata sp. nov.; 2, Trichorhina crassisetae sp. nov.; 3, Trichorhina lenkoi sp. nov.; 4, Trichorhina myrmecophila sp. nov.; 5, Trichorhina orensis sp. nov.; 6, Trichorhina sexdens sp. nov.; 7, Trichorhina tropidocerata sp. nov.

Figs. 108–117. Trichorhina tropidocerata sp. nov. Female, habitus: 108, dorsal; 109, cephalothorax and first pereonite, lateral view; 110, cephalo- thorax, frontal view. Male: 111, antenna; 112, left mandible; 113, right mandible; 114, fan-shaped scale-seta of pereonite; 115, nodulus lateralis; 116, exite of maxillula; 117, maxilliped. Scale bars: Figs 108–109, 1 mm; Fig. 110, 0.5 mm; Figs 114–115, 0.01 mm; Figs 111–113, 116–117, 0.1 mm.

Figs. 118–124. Trichorhina tropidocerata sp. nov., male: 118, pereopod VII; 119, pereopod I; 120, exopod of pleopod I; 121, endopod of pleopod I; 122, endopod of pleopod II; 123, exopod of pleopod II; 124, exopod of pleopod V. Scale bars: 0.1 mm