Camelobaetidius maranhensis Salles and Serrão, 2005

Boldrini, R., Salles, F. F. & Pes, A. M. O., 2012, Review of the genus Camelobaetidius Demoulin (Ephemeroptera: Baetidae) with reduced terminal filament, Journal of Natural History 46 (33 - 34), pp. 2033-2073 : 2062-2066

Camelobaetidius maranhensis Salles and Serrão, 2005

( Figures 5E ; 6D ; 7D; 10B; 15; 16)

Salles and Serrão 2005: 276; Domínguez et al. 2006: 645; Boldrini and Salles 2009: 10.

Diagnosis

Camelobaetidius maranhensis differs from the other described species of the genus with the terminal filament reduced based on the following combination of characteristics of nymphs: (1) segment II of labial palp with distomedial projection slightly produced ( Figure 15F ); (2) pronotum with submedial pair of tubercles ( Figure 10B ); (3) small thoracic gill present at the base of forecoxa; (4) tarsal claws with 29–34 denticles; (5) paraprocts with two fine and simple setae near inner margin ( Figure 16C ).

Redescription

Nymph. Length of body: 2.9 mm; antennae: 1.6 mm; cerci: 3.2 mm; terminal filament: 0.1 mm; tibia I: 0.8 mm; tibia II and III: 1.8 mm.

Head ( Figure 6D ). Brown, vertex with irregular light brown marks. Turbinate portion of male compound eyes light reddish brown. Antennae with scape and pedicel subcylindrical, with short, fine, simple setae on apex of each segment. Lateral branch of epicranial suture sinuous. Labrum ( Figure 15A ). Rectangular, broader than long; dorsal surface flat. Length about 0.5 × maximum width; distal margin with shallow U-shaped medial emargination; lateral margin with long, fine, simple setae; anterolateral margin with long, fine, pectinate setae; medially with short, robust, pectinate setae. Dorsally with few short, fine, simple setae scattered over basal area; dorsolateral arc of setae with a row of 15 long, fine, apically pointed setae. Ventrally with short, spine-like setae on lateral and anterolateral margin. Left mandible ( Figure 15B ). Inner and outer incisors fused, worn; prostheca robust, apically denticulate; margin between prostheca and mola straight, with a row of spine-like setae; subtriangular process narrow; tuft of setae at apex of mola absent; basal half with short, fine, simple setae scattered over dorsal area. Right mandible ( Figure 15C ). Inner and outer incisors fused, worn; prostheca slender, apically denticulate; margin between prostheca and mola straight, with a row of spine-like setae; tuft of spine-like setae at base of mola present; tuft of setae at apex of mola present; basal half with short, fine, simple setae scattered over dorsal area. Hypopharynx ( Figure 15D ). Lingua subequal in length to 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 ( Figure 15E ). Crown of galea-lacinia with inner dorsal row of setae with three pectinate denti-setae. Medial protuberance of galea with 1 + 3 long, fine, simple setae. Maxillary palp subequal in length of galea-lacinia. Palp segment II subequal in length of segment I; maxillary palp with fine, simple setae scattered over surface. Labium ( Figure 15F ). Glossa narrow and subequal in length to paraglossa; inner margin with seven spine-like setae increasing in length distally; apex with three long, spine-like setae; outer margin with two long, spine-like setae; ventral surface with one short, fine, simple seta on anteromedian area and one short, fine, simple seta near apex; dorsal surface bare. Paraglossa 1.2 × length of glossa, sub-rectangular, curved inward; apex with two rows of long, fine, pectinate setae; ventral surface with one fine, simple seta near base; dorsal surface with two robust, simple setae near apex. Labial palp with segment I 0.9 × length of segments II and III combined; segment I scattered with micropores, inner and outer margins with short, simple setae; segment II with distomedial protuberance slightly produced, with long, simple setae; dorsally with a row of five fine, spine-like setae; segment III rounded, length 0.6 × width, scattered with simple setae, and fine, simple, spine-like setae.

Thorax ( Figure 5E ). Light brown. Hind wing pad present. Pronotum with medial pair of tubercles ( Figure 10B ). Small thoracic gill present at the base of forecoxa. Foreleg ( Figure 16A ) light brown. Tibia I 1.0 × length of femur I; tarsi I 0.4 × length of femur I. Forefemur. Length about 2.9 × maximum width; dorsally with row of c.40 long, spine-like setae; length of setae 0.3 × maximum width of femur; ventrally with short, spine-like setae scattered over surface, anterior surface with short, spine-like setae near inner margin and median region. Tibia. Dorsally with a row of short, fine, simple setae; ventrally with scattered 18 short, spine-like setae; anterior surface with long, fine, simple setae; posterior surface with short, spine-like setae near apex, increasing in length toward apex; tibiopatellar suture more than half length of tibia, 0.7 × length of tibia. Tarsus. Dorsally with short, fine, simple setae; ventrally with eight spine-like setae, increasing in length toward apex, and one long, fine, simple seta near apex. Tarsal claws with 29–34 denticles. Tibia II and III 1.0 × in length of femur II and III, respectively; tarsi II and III 0.3 × in length of femur II and III, respectively.

Abdomen ( Figure 5E ). Light brown, segments II and II brown, segment V with brown marks. Terga IV with surface creased ( Figure 2B ); posterior margin with truncate spines. Gills ( Figure 16B ) light brown; margins with narrow spine-like setae intercalating short, fine, simple setae; tracheae pigmented, extended from main trunk. Gills oval. Gill I 1.5 × length of segment II; gill IV 1.6 × length of segment V; gill VII 1.5 × length of segment VIII. Paraproct ( Figure 16C ) with two fine, simple setae near to inner margin; surface shagreened with fine and simple setae. Terminal filament 0.03 × length of cerci. Cerci light brown; outer margin with tufts of long and simple setae.

Comments

This species was described based on nymphs from Brazil, from the state of Maranhão (Salles and Serrão 2005). Recently one of us (RB) was able to collect more material in the type locality (until now the only place where this species has been found). The nymphs are found more often in areas with moderate currents. Camelobaetidius maranhensis is possibly closely related to C. billi and C. rufiventris , once they present the unique combination of characteristics: terminal filament reduced, and projection on the inner margin of the forefemora absent. It is easily distinguished from the other species of the genus with terminal filament reduced by the presence of tubercles on pronotum.

Distribution

BRAZIL: Maranhão.

Material examined

Paratype. Two nymphs, one mounted on slide; one slide of legs of the type species, BRAZIL, Maranhão, Riachão, Riacho Cocal , Cachoeira Santa Bárbara , 07 ◦ 13 ′ 462 ′′ S, 46 ◦ 27 ′ 246" W, 07 August 2001, Hamada, N. leg ( PPGBT) . Fourteen nymphs, BRAZIL, Maranhão, Riachão, Riacho Cocal , Cachoeira Santa Bárbara , 07 ◦ 13 ′ 462" S, 46 ◦ 27 ′ 246" W, 23 July 2010, Boldrini, R ., Cruz , P. V . and Hamada, N. leg ( PPGBT).

Figures

Figure 2. Camelobaetidius billi, nymph. (A) Foreleg; (B) posterior margin of terga IV; (C) gill IV; (D) paraproct.

Figure 5. Camelobaetidius spp., nymphs (d.v.). (A) C. billi; (B) C. francischettii; (C) C. ipaye; (D) C. leentvaari; (E) C. maranhensis; (F) C. rufiventris.

Figure 6. Camelobaetidius spp., nymphs. (A) C. billi (head, f.v.); (B) C. francischettii (head, f.v.); (C) C. ipaye (head, f.v.); (D) C. maranhensis (head, f.v.); (E) C. rufiventris (head, f.v.); (F) C. billi (v.v); (G) C. billi (detail of thoracic gill).

Figure 10. (A) Camelobaetidius francischettii (detail of prosternum, ventro-lateral v.); (B) Camelobaetidius maranhensis (detail of pronotum, dorso-lateral v.).

Figure 15. Camelobaetidius maranhensis, nymph. (A) Labrum (left v.v., right d.v.); (B) left mandible; (C) right mandible; (D) hypopharynx; (E) maxilla; (F) labium (left v.v., right d.v.).

Figure 16. Camelobaetidius maranhensis, nymph. (A) Foreleg; (B) gill IV; (C) paraproct.