Camelobaetidius carolinae Boldrini & Pes, 2014, sp. nov.

Camelobaetidius carolinae sp. nov. Boldrini

(Figs. 2; 18–27)

Diagnose. Nymphs: 1) Labrum narrowly rounded anteriorly (Fig. 18); 2) segment II of labial palp with a short rounded distomedial projection (Fig. 23); 3) thoracic gill absent at the base of coxae; 4) tarsal claws with six denticles, first denticle distinctly longer than others (Fig. 24 a); 5) posterior margin of terga with rounded spines (Fig. 25).

Description. Nymph. Length of body: 5.0 mm; length of antennae: 1.3 mm; length of cerci: 1.8 mm; length of terminal filament: 1.6; tibia I: 0.8 mm; tibia II: 0.6 mm; tibia III: 0.5 mm.

Head (Fig. 2). Light brown. Antennae light brown. Lateral branch of epicranial suture straight.

Labrum (Fig. 18). Narrowly rounded anteriorly, broader than long. Length about 0.7× maximum width; anterolateral margin with long, fine, bifid and pectinate setae; medially with fine, bifid and pectinate setae. Dorsally with three short, fine, simple setae scattered over basal area; dorsolateral arc of setae with one long, fine, apically pointed seta on lateral region.

Left mandible (Fig. 19). Incisors with seven denticles. Prostheca robust, apically denticulate. Margin between prostheca and mola with three spine-like setae; subtriangular process wide; setae at apex of mola absent. Basal half with six short, fine, simple setae.

Right mandible (Fig. 20). Incisors with eleven denticles. Prostheca slender, apically denticulate; margin between prostheca and mola with four spine-like setae; setae at apex of mola present. Basal half with three short, fine, simple setae.

Hypopharynx (Fig. 21). Lingua shorter than superlingua, apex rounded, with tuft of short, fine, simple setae. Superlingua not expanded, with fine, simple setae scattered over lateral and distal margin, external margin cleft subapically.

Maxilla (Fig. 22). Inner dorsal row of setae with two denti-setae, one simple denti-seta and one pectinate dentiseta, apical denti-seta at the same orientation of canines. Medial protuberance of galea with 1 + 3 long, fine and simple setae. Maxillary palp 1.1× length of galea-lacinia. Palp segment II 0.8× length of segment I. Fine and simple setae scattered over segment II of maxillary palp.

Labium (Fig. 23). Glossa shorter than paraglossa; inner margin with six spine-like setae increasing in length distally; apex with two long, spine-like setae; outer margin with three long, spine-like setae; ventral and dorsal surface bare. Paraglossa sub-rectangular, curved inward; apex with two rows of long, fine, simple setae; ventral surface with a row of four long, fine, simple setae; dorsal surface with two fine, spine-like setae near to apex. Labial palp segment II with distomedial projection short and rounded; dorsally with a row of four long, spine-like setae; segment III oblong, length 1.2× width, scattered with simple setae, and spine-like setae.

Thorax (Fig. 2). Light brown; metanotum with anterior region brown. Hind wing pad present. Thoracic gill absent at the base of coxae. Femur, tibia and tarsi light brown. Tibia I subequal in length to femur I, tibia II 0.8× length of femur II, tibia III 0.7× length of femur III; tarsi I and II 0.4× length of the respective femur, tarsi III 0.3× length of femur III.

Forefemur (Fig. 24). Length about 3.7× maximum width; dorsally with a row of c.a. 18 long, spine-like setae; ventrally with five short, fine spine-like setae. Foretibia. Dorsally with few fine, simple setae; anterior surface with four short, spine-like setae; patella-tibial suture present, 0.4× length of tibia. Tarsal claws with six denticles, first denticle distinctly longer than others (Fig. 24 a). Mid femur. Length about 3.4× maximum width; dorsally with row of c.a. 13 long, spine-like setae. Hind femur. Length about 2.9× maximum width; dorsally with row of c.a. 8 long, spine-like setae.

Abdomen (Fig. 2). Light brown, posterolateral corners of segments II–III and V–VI brown. Terga with creased surface, posterior margin of tergum IV with rounded spines (Fig. 25). Gills oval. Gills IV (Fig. 26) light brown; margins with narrow spines intercalating short, fine, simple setae; tracheae pigmented. Gill I 1.2× length of segment II; gill IV 1.9× length of segment V; gill VII 1.2× length of segment VIII. Paraproct (Fig. 27). With three spines near inner margin; without shagreened area; postero-lateral extension with marginal spines. Cerci light brown, with a brown band at mid length; outer and inner margin of terminal filament and inner margin of cerci with tufts of long, simple setae; outer margin of the cerci with spines at apex on each segment.

Etymology: The name of the species is in honor of Dr. Carolina Nieto, for her significant contributions to the knowledge of Ephemeroptera, especially Baetidae.

Distribution. BRAZIL: Rondônia.

Comments. The general shape of the labial palp of C. carolinae sp. nov. is similar to that found in C. cruzi sp. nov. and C. matilei Thomas & Péru, 2003. Camelobaetidius carolinae sp. nov., however, can be distinguished from these two species by the size of the denticles on the tarsal claws [first denticle distinctly longer than others (Fig. 24 a)], and by a more complex abdominal color pattern (Fig. 2).

Material examined. Holotype: Nymph (mounted on slides, medium Euparal), BRAZIL, Rondônia, Colorado do Oeste, Eixo Zero, Rio Hermes, 13°12'07.6''S / 60°23'25.1''W, 06.ix.2012, Boldrini, R., Nascimentos, J.M.C., Fernandes, A.S., Hamada, N. leg (INPA). Paratypes: Two immature nymphs (mounted on slides, medium Euparal), BRAZIL, Rondônia, Colorado do Oeste, Rio Cabixi, below the bridge, 13°15'31.8''S / 60°20'04.8''W, 06.ix.2012, Boldrini, R., Nascimento, J.M.C., Fernandes, A.S., Hamada, N. leg (one in CZNC and one in UFRR).