Trichorhina orensis, 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 : 249-252

Trichorhina orensis sp. nov.

( Figs 5 , 79–94 )

Type material. Holotype ♂, BRAZIL, Rio de Janeiro: Ilha de Itacuruçá, Praia dos Mocambos (supra tidal line, in garbage), 15.XII.1973, A. L. Castro & B. Prazeres col. ( MNRJ 4119 ). Paratypes: 12♂, 41♀, same data as holotype ( MNRJ 4120 ).

Diagnosis. Body unpigmented. Eyes with five brown ommatidia. Molar process of mandible with one penicil. Exite of maxillulae with seven teeth, two bifid. Measurements. Male, length: 2.48 mm, width: 0.83 mm; female, length: 2.89 mm, width: 0.99 mm.

Description. Body unpigmented. Eyes brown with five ommatidia. Pleon outline continuous with pereon ( Fig. 79 ); telson subtriangular with rounded apex of sides slightly concave. Pereon, pleon and telson covered with fan-shaped scale-setae. In the posterior margins of pereonites they are large and wide, alternating with small and narrow ones, and in the lateral margins they are small. Both median axes of fan-shaped scale-setae evident, as well as the secondary supporting axioles ( Fig. 83 ). Nodulilaterales with simple base ( Fig. 84 ). Pereonite VII with one nodulus lateralis on each side. Position of noduli laterales as illustrated ( Fig. 5 ). Uropods with a tuft of bristles in apex of exopod. Distal joint of antennula with about eight aesthetascs ( Fig. 85 ). Second joint of antennal peduncle without crest in outer border and without dorsal keel. Second joint of antennal flagellum without groove ( Fig. 82 ). Left mandible without rods between molar and incisory processes. Number of penicils in molar process of left mandibles one, right one ( Fig. 86 ). Outer group of exite of maxillulae with three teeth. Inner group of exite of maxillulae with four teeth: two bifid ( Fig. 87 ). Maxilla with inner lobe narrower than outer lobe. Sensilla on the inner lobe, with a sinuous median margin ( Fig. 88 ). Endite of maxilliped with two small teeth in distal outer border, and with inner distal border smooth ( Fig. 89 ). Pleopods without respiratory areas.

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Male. Carpus of pereopod Iof male ( Fig. 90 ) with bristle field. Pereopod VII ( Fig. 91 ) without sexual dimorphism. Pleopod Iwith endopod with distal half turned to the outside and apex slightly crenulate ( Fig. 92 ). Pleopod II ( Fig. 93 ) with triangular exopod; endopod with distal half strongly narrowed. Pleopod V with subtriangular exopod ( Fig. 94 ).

Remarks. Trichorhina orensis sp. nov. is distinguished from other species with four to six ommatidia, as follows: from T. acuta by molar process of mandibles with one penicil (six in T. acuta ). From T. argentina by 1) body unpigmented (purplish uniform pigmentation in T. argentina ); 2) brown ommatidia (black in T. argentina ); 3) coxal plates without glandular pores. From T. australiensis by exite of maxillulae with seven teeth, of which two bifid (in T. australiensis nine, five bifid), and endite of maxilliped without tooth in distal inner border. 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 (with about seven in T. biumbonata ); 3) endite of maxilliped with two teeth in distal outer border (one in T. biumbonata ). From T. hospes by exite of maxillulae with seven teeth, of which two bifid (in T. hospes nine, two bifid). From T. lenkoi sp. nov. by endite of maxilliped without teeth in inner distal border, and dactylus of pereopod Iof male with inner seta larger. From T. myrmecophila sp. nov. by theinner group of exiteof maxillulaewith two bifid teeth (four undivided teeth in T. myrmecophila ), and endopod of pleopod II of male without row of scale-setae. From T. pallida by the molar process of mandibles with one penicil (two in T. pallida ), and endopod of pleopod Iof male with distal half turned to the outside (straight in T. pallida ). From T. papillosa by the molar process of mandibles with one penicil (three in T. papillosa ), and endite of maxilliped with two teeth in outer distal border. From T. paraensis byexiteof maxillulaewithseven teeth, of which two bifid (in T. paraensis eight, two bifid), and endite of maxilliped without teeth in inner distal border (with one tooth in inner distal border in T. paraensis ). From T. silvestrii by distal joint of antennula with about eight aesthetascs (four in T. silvestrii ), and molar process of mandibles with one penicil (three in T. silvestrii ). From T. vandeli by molar process of mandibles with one penicil (with a group of many penicils in T. vandeli ), and exite of maxillulae with seven teeth, of which two bifid (in T. vandeli eight, two bifid).

Etymology. From Latin ora = beach, referring to microhabitat where the individuals were collected.

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. 79–89. Trichorhina orensis sp. nov. Female, habitus: 79, dorsal; 80, cephalothorax and two first pereonites, lateral view; 81, cephalothorax, frontal view. Male: 82, antenna; 83, fan-shaped scale-seta of pereonite; 84, nodulus lateralis; 85, antennula; 86, right mandible; 87, exite of ma- xillula; 88, maxilla; 89, maxilliped. Scale bars: Fig. 79, 1 mm; Figs 80–81, 0.5 mm; Figs 83–84, 0.01 mm; Figs 82, 85–89, 0.1 mm.

Figs. 90–94. Trichorhina orensis sp. nov., male: 90, pereopod I; 91, pereopod VII; 92, endopod of pleopod I; 93, pleopod II; 94, exopod of pleopod V. Scale bars: Figs 90–94, 0.1 mm; arrowed details, 0.01 mm.