Cloeodes opacus Nieto & Richard, 2008, n. sp

Cloeodes opacus n. sp. (Figs. 43���51) Nymph (Fig. 43). Length: body, 5.3���5.5 mm; cerci, 2.2���2.3; terminal filament, 1.9 ���2.0 mm. Antennae, 1.8��� 1.9 mm. Head dark brown, longer than wide; compound eyes in the male brown. Antennae: scape and pedicel dark brown, flagellum pale yellow, 2 times the head capsule; pedicel 1.5 times the length of the scape. Mouthparts: labrum (Fig. 44) with one subapical seta centrally and two setae near lateral margin, anterior margin with basally bifid setae near midline and apically bifid setae near lateral margin (Fig. 45). Left mandible (similar to Fig. 57), without setae between prostheca and mola, thumb of molar area transverse to anterior margin. Right mandible (similar to Fig. 58) without setae between prostheca and mola, prostheca bifid. Hypopharynx (similar to Fig. 9): lingua blunt apically. Maxillae (similar to Fig. 60), palpi as long as galea-lacinia, two segmented, segment II with a constriction. Labium (Fig. 46), segment III of palpi subquadrangular. Thorax dark brown, with spots as in Fig. 43. Fore wings yellowish brown, sterna pale yellow. Legs (Fig. 47) dark brown. Femora dorsally with a row of blunt spines, apically with a quadrangular projection with two blunt spines (Fig. 48). Tarsi with a row of spines. Tarsal claws 0.3 times the length of tarsi. Hind wing pads absent. Abdomen dark brown, color pattern with segments I���IX with medial yellow markings as in Fig. 43, segment X brown. Posterior margin of terga with spines as in Fig. 49. Sterna pale yellow, segments II���VI with a small tuft of long fine setae laterally on each side. Gills (Fig. 50) translucent white and rounded, 2 times the length of each tergum, main branch of trachea and a few secondary branches pigmented. Paraprocts, with spines apically as in Fig. 51. Cerci pale yellow, apical third yellowish brown with flattened setae basally sclerotized (similar to Fig. 30). Cerci with long spines toward external margin every two segments, terminal filament with long spines toward midline ventrally and dorsally every two segments (similar to Fig. 14). Etymology. Opacus: from Latin, dark. For the general coloration of this species. Diagnosis. Cloeodes opacus n. sp. can be distinguished from the other species of the genus by the following combination of characters: 1) dorsal edge of femora with a row of blunt spines, apically with a subquadrangular projection (Fig. 48); 2) abdominal color pattern dark brown with segments I���IX with medial yellow markings as in Fig. 43, segment X brown; 3) hind wing pads absent; 4) segment III of labial palpi subquadrangular (Fig. 46); 5) caudal filaments with flattened setae basally sclerotized (similar to Fig. 30), cerci with long spines toward external margin every two segments, terminal filament with long spines toward midline dorsally and ventrally every two segments (similar to Fig. 14). Material. Holotype: female nymph: ARGENTINA, Misiones, Pque. Prov. Urugua-i, Paraje Ma. Soledad, arroyo afluente R��o Tateto, S 25 �� 51 ' 39 '', W 53 �� 58 ' 55 '', 410 m, 30 / XI/ 2001, Dom��nguez, Orce & Nieto colls. Paratypes: 7 nymphs, same data as holotype. Material housed in IFML.
Published as part of Nieto, Carolina & Richard, Barton, 2008, The genus Cloeodes (Ephemeroptera: Baetidae) in Argentina with new generic synonymy and new species, pp. 1-21 in Zootaxa 1727 on page 13, DOI: 10.5281/zenodo.181238