Trichorhina myrmecophila, 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 : 247-249

Trichorhina myrmecophila sp. nov.

( Figs 4 , 58–78 )

Type material. Holotype ♂, BRAZIL, São Paulo: Barueri, in nest of Camponotus rufipes (Fabricius, 1775) ( Hymenoptera , Formicidae ), 14.X.1967, K. Lenko col. ( MNRJ 4117 ). Paratypes: 3♂, 18♀, same data as holotype ( MNRJ 4118 ).

Diagnosis. Pigmentation of body pale yellow. Eyes with five black ommatidia. Pleopod Iof male with exopod slightly rounded; endopod with apex with row of micro-setae.

Measurements. Male, length: 3.00 mm, width: 1.00 mm; female, length: 2.30 mm, width: 0.92 mm.

Description. Pigmentation of body faint, pale yellow, with small brown spots in head. Eyes black with five ommatidia. Head partly sunken in pereonite I, anterior margins of pereonite Ireaching the eyes. Cephalic lateral lobes slightly ahead of median lobe which has apex rounded and straight sides ( Figs 59, 60 ). Pleon slightly narrower than pereon, pleonites III–V with well developed points ( Fig. 58 ). Body surface with hexagonal plates. Pereon, pleon and telson covered with fan-shaped scale-setae bearing two axial rods ( Fig. 63 ). Nodulilaterales withfeaturelessbase ( Fig. 62 ). Pereonite VII with only one nodulus lateralis on each side. Position of noduli laterales as illustrated ( Fig. 4 ). Antennula with middle joint much smaller than others, distal joint with five aesthetascs ( Fig. 61 ). Antenna ( Fig. 64 ) 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 with a slightly transversal groove. Left mandible ( Fig. 65 ) without rods between molar and incisory processes. Number of penicils in molar process of left mandibles one ( Fig. 65 ), right one ( Fig. 66 ). Outer group of exite of maxillulae with three teeth. Inner group of exite of maxillulae with four simple teeth ( Fig. 67 ). Maxilla with inner lobe narrower than outer lobe wich is apically truncate. Sensilla on the inner lobe ( Fig. 68 ). Endite of maxilliped with two small teeth in outer distal border, and irregular inner distal border ( Fig. 69 ). Pleopods without respiratory areas.

Male. Pereopods I ( Fig. 70 ) and VII ( Fig. 71 ) without apparent sexual dimorphism (see pereopods I and VII of female in figures 73 and 72, respectively). Carpus of pereopod Iof male without bristle field. Pleopod Iwith exopod rounded ( Fig. 74 ); endopod ( Fig. 75 ) with distal half slightly turned to the outside and apex armed with a short row of micro-setae parallel to the inner border. Pleopod II with triangular exopod ( Fig. 77 ); endopod with distal half gradually tapered ( Fig. 76 ). Pleopod V with sub-rectangular exopod ( Fig. 78 ).

Remarks. Trichorhina myrmecophila sp. nov. is distinguished fromother species with eye 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 seven undivided teeth (two of inner group bifid in T. acuta ). From T. argentina by 1) exopod of pleopod Iof male rounded (ovoid in T. argentina ); 2) endopods of uropods relatively longer. From T. australiensis by 1) antennula with joints of different proportions; 2) exite of maxillulae with seven undivided teeth (in T. australiensis nine, five of which bifid); 3) exopod of pleopod Iof male rounded (narrowed in inner side in T. australiensis ). From T. barbouri by 1) 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 upper outer margin (one in T. biumbonata ); 4) pereopod Iof male with setae undivided (with up to four points in T. biumbonata ). From T. hospes by 1) antennula with distal joint with five aesthetascs (six in T. hospes ); 2) exiteof maxillulaewithsevenundividedteeth (in T. hospes nine, two bifid). From T. lenkoi sp. nov. by 1) pigmentation of body pale yellow (light brown in T. lenkoi ); 2) eyes black (light brown in T. lenkoi ); 3) pleon slightly narrower than pleon (continuous with pereon in T. lenkoi ); 4) endopod of pleopod Iof male with row of micro-setae in apex. From T. pallida by 1) molar process of mandibles with one penicil (two in T. pallida ); 2) exite of maxillulae with seven undivided teeth (in T. pallida seven, two bifid); 3) exopod of pleopod Iof male rounded (elliptic in T. pallida ). From T. papillosa by 1) molar process of mandibles with one penicil (three in T. papillosa ); 2) exite of maxillulae with seven undivided teeth (in T. papillosa seven, two bifid); 3) endite of maxilliped with two teeth in distal outer border. From T. paraensis by 1) pereon, pleon and telson with fan-shaped scale-setae (with ovoid scale-setae in T. paraensis ); 2) endite of maxilliped with two teeth in outer distal border (with one tooth in T. paraensis ). From T. silvestrii by 1) distal joint of antennula with five aesthetascs (four in T. silvestrii ); 2) exite of maxillulae with seven undivided teeth (in T. silvestrii eight, two bifid). From T. vandeli by 1) distal joint of antennula with five aesthetascs (seven to eight in T. vandeli ); 2) molar process of mandibles with one penicil (with a group of many penicils in T. vandeli ).

Etymology. Species name stems from Greek and refers to the collecting of the type series in nest of ants.

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. 58–69. Trichorhina myrmecophila sp. nov. Female, habitus: 58, dorsal; 59, cephalothorax and two first pereonites, lateral view; 60, cepha- lothorax, frontal view. Male: 61, antennula; 62, nodulus lateralis; 63, fan-shaped scale-seta of pereonite; 64, antenna; 65, left mandible; 66, right mandible; 67, exite of maxillula; 68, maxilla; 69, maxilliped. Scale bars: Fig. 58, 1 mm; Figs 59–60, 0.5 mm; Figs 62–63, 0.01 mm; Figs 61, 64–69, 0.1 mm

Figures 70–78. Trichorhina myrmecophila sp. nov. Male: 70, pereopod I; 71, pereopod VII. Female: 72, pereopod VII; 73, pereopod I. Male: 74, exopod of pleopod I; 75, endopod of pleopod I; 76, endopod of pleopod II; 77, exopod of pleopod II; 78, exopod of pleopod V. Scale bars: Figs 70–78, 0.1 mm; arrowed details, 0.01 mm