Paracloeodes assu, 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 : 7-8

Paracloeodes assu sp. n. ( Figs. 1–11 )

Mature nymph. Length: body, 6.6–6.8 mm; cerci and terminal filament broken. Antennae, 3.5 mm, more than 3 times the head capsule. Head yellowish­brown. Frontal keel absent, ocelli dark brown. Antennae yellowish­brown. Mouthparts: labrum ( Fig. 1 a), dorsally with a pair of subapical setae near middle, apical margin with two kinds of setae: basally bifid setae near the midline and simple and bipectinate setae near lateral margin ( Fig. 1 b). Mandibles ( Figs. 2 a­3): external margins straight. Prostheca of left mandible ( Fig. 2 a) with 2 denticles. Lingua subequal in length to superlingua and rounded apically ( Fig. 4 ). Maxillae with palpi 2.0 times the length of galea­lacinia ( Fig. 5 ). Labium ( Figs. 6 a–b) with segment II of palpi with rounded distomedial projection, 2.1 times width of segment III, segment III conical.

Thorax yellowish­brown, without color pattern. Pleura and sterna yellowish brown. Legs ( Fig. 7 ) yellowish­white, tarsal claws 0.3 times the length of tarsi, with 2 rows of denticles, small basally, increasing in size distally ( Fig. 8 ). Hind wing pads present.

Abdomen yellowish­brown, without distinct color pattern. Posterior margin of terga with spines as long as wide ( Fig. 9 ). Sterna yellowish­brown. Gills whitish, external margin sclerotized, main branch of trachea weakly pigmented ( Fig. 10 ). Paraprocts with 19 spines apically ( Fig. 11 ).

Adults. Unknown.

Etymology. From the Tupi­guarani language açu, meaning large. An allusion to the size of the species.

Discussion. This species can be distinguished from the other species of the genus by the following combination of characters, 1) frontal keel absent; 2) labrum with a pair of subapical setae near middle ( Fig. 1 a); 3) labium with segment II of palpi with rounded distomedial projection, 2.1 times the width of segment III ( Fig. 6 b); 4) tarsal claws 0.3 times the length of tarsi ( Fig. 7 ); 5) hind wing pads present; 6) posterior margin of abdominal terga with spines as long as wide ( Fig. 9 ); 7) gills with main branch of trachea poorly pigmented ( Fig. 10 ); 8) paraprocts with 19 spines apically ( Fig. 11 ).

Material. Holotype, female nymph: BRAZIL, Rio de Janeiro State, Itatiaia, córrego ao lado da estrada do Abrigo Rebouças km 10, 16/ X/ 1997, Salles col. Paratypes: 4 nymphs same data (mouthparts, legs and paraprocts of one nymph mounted on slides). The holotype and 2 paratypes are deposited at IBRJ. Other paratypes are deposited at IFML.

Figures

FIGURE 1 – 11. Paracloeodes assu sp. n. Nymph. Mouthparts (Figs. 1 – 6): 1 a, labrum d. v.; 1 b, labrum: apical setae; 2 a, left mandible v. v.; 2 b, detail of teeth of molars; 3, right mandible v. v.; 4, hypopharynx v. v.; 5, maxilla v. v.; 6 a, labium, left d. v., right v. v.; 6 b, palp: segments II – III. 7, leg I; 8, tarsal claw I. 9, posterior margin of tergum IV. 10, gill IV. 11, paraproct.