Arthrosolaenomeris iara n. sp.

Figures 9, 10G–H, 11

urn:lsid:zoobank.org:act: AEBF860A-7309-4E68-BE80-F2A27710CDD0

Type material. Male holotype from Usina Hidrelétrica Guaporé, Vale São Domingos and Pontes de Lacerda (15°11’60”S, 59°22’00”W), Mato Grosso, Brazil, 03.X.2002, G. Marçal coll., deposited in IBSP 1577 . Paratypes: one male and one female from Chapada dos Parecis, Diamantino (14°09’43”S, 57°08’01”W), Mato Grosso, Brazil, XI.1993, D. Novais and R . Pardini coll., deposited in IBSP 7537 .

Additional material. BRAZIL: Mato Grosso: Vila Bela da Santíssima Trindade (15°00’00”S, 59°57’00”W), Fazenda Barranco Alto, 4♂, 2♀ and one juvenile, 14.XI.2015, A. Chagas-Jr and A.B. Kury coll. (CZUFMT 841); Porto Esperidião (15°51’11”S, 58°27’36”W), 1♂, 18–22.XII.1976, P.E. Vanzolini coll. (MZSP 1081) .

Diagnosis. Adult males differ from all other species of the genus by the absence of the secondary process in the prefemoral process (Fig. 9D).

Description. Male (Holotype, IBSP 1577). Coloration (long-preserved in 70% ethanol): Head and antennae ochre with the seventh antennomere darker. Body ocher and paranota tip with the same color as the body (Figs 9A– C). Legs ocher whitish. Telson ocher. Total length: 68.40. Total width: 10.13mm. Collum 2.93 length, 9.89 width. Antennomere lengths (1>7): 0.77; 2.12; 1.93; 1.62; 1.70; 1.49; 0.44. Podomeres lengths (1>7): 1.24; 1.70; 2.64; 1.51; 1.96; 2.00; 0.56. Gonopod aperture 2.13 length, 3.83 width. Telson 1.43 length. Gonopod: 2.92 length, 2.90 width. Gonocoxae: 1.18 length, 1.50 width. Telopodite: 2.92 length, 1.48 width. Prefemoral region 1/3 the size of telopodite. Prefemoral process long and acute, starting from an angle of 180°, ascending parallel to the solenomere and partially covering it in mesal view (Fig. 9D). Solenomere long, wide in the middle zone due to the presence of the cingulum and narrowing at the apex (Fig. 9F). Cingulum in medial position (Fig. 9F). Apex of the solenomere abruptly descending (Fig. 9D).

Female (paratype, IBSP 7537). Body as in male, except for sternites with triangular projections, legs showing dorsal projections not conspicuous and without granules. Total length: 69.42. Total width: 9.49. Collum 3.15 length, 8.82 width. Antennomere lengths (1>7): 0.73; 1.95; 1,45; 1.30; 1.35; 1.22; 0.35. Podomeres lengths (1>7): 0.83; 1.06; 2.06; 1.04; 1.44; 1.50; 0.46. Telson 1.46 length. Epigyne rounded with irregular edges. Vulvae (Figs 10G–H): 1.42 length, 0.67 width. External valve: 1.01 length, 0.30 width. Internal valve: 0.99 length, 0.28 width. Operculum: 0.44 length, 0.54 width.

Distribution. Mato Grosso, Brazil (Fig. 11).

Etymology. The species epithet is a reference of the Brazilian folkloric character “Iara”. According to the indigenous legend, Iara is a beautiful mermaid that inhabits the rivers of the north of the country. Noun in apposition.