Paracloeodes yuto, Nieto, Carolina & Salles, Frederico Falcaõ, 2006

Nieto, Carolina & Salles, Frederico Falcaõ, 2006, Revision of the Genus Paracloeodes (Ephemeroptera: Baetidae) in South America, Zootaxa 1303, pp. 1-33 : 15

Paracloeodes yuto sp. n. ( Figs. 96–107 )

Mature nymph. Length: body, 3.2–3.3 mm; cerci, 1.1–1.2 mm, terminal filament, 1.2 mm. Antennae, 1.0– 1.1 mm, 2 times the head capsule. Head pale yellow. Frontal keel present, ocelli yellowish­brown. Antennae pale yellow. Mouthparts: labrum ( Fig. 96 ), dorsally with a pair of subapical setae near middle. Mandibles ( Figs. 97–98 ): external margins straight. Prostheca of left mandible ( Fig. 97 ) with 2–3 denticles. Lingua ( Fig. 99 ) slightly shorter than superlingua and rounded apically. Maxillae with palpi 1.5 times the length of galea­lacinia ( Fig. 100 ). Labium ( Figs. 101 a–b) with segment II of palpi with a strong rounded distomedial projection, 2.8 times width of segment III, segment III conical. Thorax yellowish­brown. Pronotum with a pale yellow median band. Anterior margin of mesonotum brownish. Forewing pads yellowish­brown. Pleura and sterna pale yellow. Legs ( Fig. 102 ) yellowish, tarsal claws yellowish brown, 0.75 times the length of tarsi, with 2 rows of minute denticles basally ( Fig. 103 ). Hind wing pads absent.

Abdomen yellowish, anterior margins of terga brownish, tergum IX yellowish­brown. Posterior margin of terga with spines 1.8 times longer than wide ( Fig. 104 ). Sterna pale yellow. Gills ( Fig. 105 ) blackish. Paraprocts with 9 spines ( Fig. 106 ). Caudal filaments yellowish with crown of spines on each segment ( Fig. 107 ).

Adults. Unknown.

Etymology. Yuto is the name of the river where this species was collected.

Discussion. This species can be distinguished from the other species of the genus by the following combination of characters, 1) frontal keel present; 2) antennae 2 times the head capsule; 3) labrum with a pair of subapical setae near middle ( Fig. 96 ); 4) lingua ( Fig. 99 ) slightly shorter than superlingua and rounded apically; 5) maxillary palpi 1.5 times the length of galea­lacinia; 6) segment II of labial palpi with strong distomedial projection 2.8 times width of segment III ( Fig. 101 b); 7) hind wing pads absent; 8) tarsal claws long, 0.75 times the length of tarsi, with two rows of minute denticles ( Figs. 102–103 ); 9) posterior margin of abdominal terga with spines 1.8 times longer than wide ( Fig. 104 ); 10) caudal filaments with crown of spines on each segment ( Fig. 107 ).

Material. Holotype: nymph, ARGENTINA: Jujuy, Depto. Ledesma, A° Yuto . S 23°38´36´´, W 64°32´25´´, 500 m; Ph: 6.5; T: 33°C; 4–5/ IV/ 2004, Nieto & Mesa col. Paratypes: 28 nymphs same data. The holotype and 20 paratypes are deposited at IFML. Other paratypes are housed at IBRJ.

Figures

FIGURE 96 – 107. Paracloeodes yuto sp. n. Nymph. Mouthparts (Figs. 96 – 101): 96, labrum, left d. v., right v. v.; 97, left mandible v. v.; 98, right mandible v. v.; 99, hypopharynx v. v.; 100, maxilla v. v.; 101 a, labium, left d. v., right v. v.; 101 b, palpi, left d. v., right v. v. 102, leg I; 103, tarsal claw I. 104, posterior margin of tergum IV. 105, gill IV. 106, paraproct. 107, detail of cercus.