Trichorhina lenkoi, 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 : 247

Trichorhina lenkoi sp. nov.

( Figs 3 , 44–57 )

Type material. Holotype ♂, BRAZIL, São Paulo: São Roque, Araçariguama , in the leaf mold, 11.IV.1970, K. Lenko col. ( MNRJ 4115 ). Paratypes: 4♂, 2♀, same data as holotype ( MNRJ 4116 ).

Diagnosis. Pigmentation of body brown. Eyes with five ommatidia light brown. Exite of maxillulae with six undivided teeth plus one bifid tooth.

Measurements. Male, length: 3.03 mm, width: 1.10 mm; female, length: 2.34 mm, width: 0.96 mm.

Description. Pigmentation of body brown, with small dark brown spots in head. Eyes light brown with five ommatidia, not contiguous. Pereonite Iwith anterior margins reaching the eyes. Cephalic lateral lobes small, shorter than median lobe which has apex rounded and straight sides ( Fig. 44 ). Pleon outline continuous with pereon; telson subtriangular with sides slightly convex. Surface with hexagonal plates. Pereon, pleon and telson covered with fan-shaped scale-setae ( Fig. 46 ), with four axial rods. Nodulilaterales ( Fig. 45 ) with featureless base. Pereonite VII with only one nodulus lateralis on each side. Position of noduli laterales as illustrated ( Fig. 3 ). Antennula withdistaljointwithabout five aesthetascs. Antenna ( Fig. 47 ) stretched reaches posterior margin of pereonite II. Second joint of antennal peduncle without crest in outer border and without dorsal keel. Second joint of antennal flagellum without groove. Left mandible ( Fig. 48 ) without rods between molar and incisory processes. Number of penicils in molar process of left mandibles one ( Fig. 48 ), right one ( Fig. 49 ). Outer group of exite of maxillulae with three teeth. Inner group of exite of maxillulae with four teeth: one bifid ( Fig. 50 ). Maxilla with inner lobe narrower than outer lobe. Sensilla on the inner lobe. ( Fig. 51 ). Endite of maxilliped with two small teeth in distal outer border, and with inner distal border smooth ( Fig. 52 ). Pleopods without respiratory areas.

Male. Pereopods I ( Fig. 53 ) and VII ( Fig. 54 ) without apparent sexual dimorphism. Endopod of pleopod Iwith distal half slightly turned to the outside, apex simple ( Fig. 55 ). Pleopod II with exopod triangular ( Fig. 57 ); endopod with distal half slender ( Fig. 56 ).

Remarks. Trichorhina lenkoi sp. nov. is distinguished from other species with four to six ommatidia as follows: from T. acuta by 1) molar process of mandibles with one penicil (six in T. acuta ); 2) exite of maxillulae with six undivided teeth and one bifid (two of inner group bifid in T. acuta ). From T. argentina by 1) antenna shorter; 2) eyes light brown (black in T. argentina ); 3) coxal plates without glandular pores. From T. australiensis by 1) exite of maxillulae with six undivided teeth and one bifid (in T. australiensis nine, inner group with all bifid); 2) presence of frontal lobe. From T. barbouri by second joint of antennal flagellum without groove and tegument smooth. From T. biumbonata sp. nov. by 1) second joint of antennal peduncle without crest in outer border; 2) molar process of mandibles with one penicil (five to seven in T. biumbonata ). From T. hospes by 1) exiteof maxillulae with six undivided teeth and one bifid (in T. hospes nine, two bifid); 2) endite of maxilliped with two teeth in outer distal border (without teeth in T. hospes ). From T. pallida by 1) molar process of mandibles with one penicil (two in T. pallida ); 2) exite of maxillulae with six undivided teeth and one bifid (two of inner group bifid in T. pallida ). From T. papillosa by 1) molar process of mandibles with one penicil (three in T. papillosa ); 2) exite of maxillulae with six undivided teeth and one bifid (two bifid in T. papillosa ); 3) endite of maxilliped with two teeth in outer distal border and one in inner distal border. From T. paraensis by 1) exite of maxillulae with six undivided teeth and one bifid (in T. paraensis eight, two bifid); 2) endite of maxilliped with two teeth in distal outer border (with one tooth in distal outer border and one tooth in inner border in T. paraensis ). From T. silvestrii by 1) molar process of both mandibles with one penicil (with three penicils in T. silvestrii ); 2) exite of maxillulae with six undivided teeth and one bifid (in T. silvestrii eight, two bifid). From T. vandeli by 1) antennula with distal joint with about five aesthetascs (with seven to eight aesthetascs in T. vandeli ); 2) exite of maxillulae with six undivided teeth and one bifid (in T. vandeli eight, two bifid).

Etymology. Species named after Karol Lenko, who collected the type series, and many other Brazilian Oniscidea.

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. 44–57. Trichorhina lenkoi sp. nov., male: 44, cephalothorax, frontal view; 45, nodulus lateralis; 46, fan-shaped scale-seta of pereonite; 47, antenna; 48, left mandible; 49, right mandible; 50, exite of maxillula; 51, maxilla; 52, maxilliped. Scale bars: Fig. 44, 0.5 mm; Figs 45–46, 0.01 mm; Figs 47–52, 0.1 mm; 53, pereopod I; 54, pereopod VII; 55, endopod of pleopod I, detail; 56, endopod of pleopod II; 57, exopod of pleopod II. Scale bars: 0.1 mm.