Camelobaetidius metae Salinas-Jimenez & Boldrini, 2019

Salinas-Jimenez, Luis Gonzalo, Boldrini, R., Osorio-Ramirez, Diana Paola, Caro, Clara Ines & Rojas-Peña, Jose Ismael, 2019, A new species of Camelobaetidius Demoulin, 1966 (Ephemeroptera: Baetidae), from the Colombian Orinoco River basin, Zootaxa 4656 (2), pp. 367-374 : 368-373

Camelobaetidius metae Salinas-Jimenez & Boldrini , sp. nov.

( Figs. 1–11 )

Diagnosis. Nymphs: 1) labrum narrowly rounded anteriorly ( Fig. 2 ); 2) incisors of right mandible with eleven denticles ( Fig. 5a ); 3) segment II of labial palp with a short rounded distomedial projection ( Fig. 7 ); 4) gills absent at the bases of coxae; 5) outer margin of forefemur with a row of about 23 long, spine-like setae ( Fig. 8 ); 6) tarsal claws with ten denticles ( Fig. 8a ); 7) posterior margin of tergum IV with truncate spines ( Fig. 9 ); 8) terminal filament almost as long as cerci.

Description. Nymph. Length of body: 3.5–4.0 mm; length of antennae: 1.0– 1.2 mm; length of cerci: 1.0 mm; length of terminal filament: 0.8 mm.

Head ( Fig. 1 ). Light brown. Antennae light brown. Lateral branch of epicranial suture sinuous.

Labrum ( Fig. 2 ). Narrowly rounded anteriorly, broader than long. Length about 0.6× maximum width; lateral and anterolateral margins 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 two long, fine, apically pointed setae in lateral region.

Hypopharynx ( Fig. 3 ). 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 margins.

Left mandible ( Fig. 4 ). Incisors with seven denticles ( Fig. 4a ). Prostheca robust, apically denticulate. Margin between prostheca and mola without setae; subtriangular process wide; setae absent from apex of mola.

Right mandible ( Fig. 5 ). Incisors with eleven denticles ( Fig. 5a ). Prostheca slender, apically denticulate; margin between prostheca and mola with two fine simple setae; setae present at apex of mola.

Maxilla ( Fig. 6 ). Inner dorsal row of setae with three denti-setae; two pectinate denti-setae and one apical dentiseta at same orientation of canines. Medial protuberance of galea with 2 long, fine and simple setae. Maxillary palp 1.1× length of galea-lacinia. Palp segment II length subequal to length of segment I. Fine and simple setae scattered over segment II of maxillary palp.

Labium ( Fig. 7 ). Glossa shorter than paraglossa; inner margin with nine spine-like setae increasing in length distally; apex with two long, spine-like setae; outer margin with three long, spine-like setae; ventral surface with three short, fine, simple setae. Paraglossa sub-rectangular, curved inward; apex with two rows of long, fine, simple setae; ventral surface with row of four long, fine, spine-like setae; dorsal surface with two fine, spine-like setae near apex. Palp segment II with distomedial projection short and rounded; dorsally with row of three long, spine-like setae; ventrally with three simple spine-like setae. Palp segment III oblong, length 1.3× width, with scattered simple setae and spine-like setae.

Thorax ( Fig. 1 ). Light brown; metanotum with anterior region brown. Hind wing pad present. Gills absent from bases of coxae. Femur, tibia and tarsi light brown. Tibia I 0.9× length of femur I; tibia II 0.8× length of femur II; tibia III 0.8× length of femur III. Tarsi I and II each 0.5× length of respective femur; tarsi III 0.4× length of femur III. Forefemur ( Fig. 8 ) length about 3.4× maximum width; outer margin with row of about 23 long, spine-like setae; inner margin with three short, fine, spine-like setae. Foretibia outer margin with few fine, simple setae; inner margin with three short, spine-like setae; anterior apex with two spine-like setae; patella-tibial suture present. Tarsal claws with 10 denticles each ( Fig. 8a ). Mid femur length about 2.6× maximum width; outer margin with row of about 9 long, spine-like setae. Hind femur length about 3× maximum width; outer margin with row of about 14 long, spinelike setae.

Abdomen ( Fig. 1 ). Coloration light brown, but segment VIII lighter. Segment X with cross-like color pattern. Posterior margin of tergum IV with truncate spines ( Fig. 9 ). Gills oval. Gills IV ( Fig. 10 ) light brown; margins with narrow spines intercalating short, fine, simple setae; tracheae pigmented. Gill I 1.4× length of segment II; gill IV 1.8× length of segment V; gill VII 1.4× length of segment VIII. Paraproct ( Fig. 11 ) with two spines near inner margin; without shagreened area. Cerci light brown with brown band at mid length; outer and inner margins of terminal filament and inner margins of cerci with tufts of long, simple setae; outer margins of cerci with spines at apex of each segment.

Etymology. The specific epithet is an arbitrary combination of letters referring to Meta, the Colombian state where this species was found.

Distribution. Thusfar, the species has been found only in the Río Orotoy, in the Orinoco River basin of Meta, Colombia ( Fig. 12 ).

Comments. The general shape of the labial palp of Camelobaetidius metae is similar to that found in C. carolinae Boldrini & Pes, 2014 , C. cruzi Boldrini & Pes, 2014 and C. matilei Thomas & Péru, 2003 . Camelobaetidius metae , however, can be distinguished from C. carolinae by the size of the denticles on the tarsal claws, with the latter species having the first denticle distinctly longer than others, while the denticles in C. metae are all similar in length. Camelobaetidius metae is distinguished from C. cruzi by the shape of labial palp segment II, which is subquandrangular in C. cruzi versus oblong in C. metae . Camelobaetidius metae is distinguished from C. matilei by the hind wing, which is present in C. metae but absent in C. matilei . Furthermore, C. metae presents an outer margin of the forefemur with a row of 23 clavate setae and a posterior margin of tergum IV with truncate spines, while C. carolinae presents an outer margin of the forefemur with a row of 18 long, spine-like setae and a posterior margin of tergum IV with rounded spines; C. cruzi presents an outer margin of the forefemur with a row of nine long, spinelike setae and the posterior margin of tergum IV with rounded spines, and C. matilei presents an outer margin of the forefemur with a row of three long, spine-like setae and a posterior margin of tergum IV with truncate spines.

Material examined. Holotype: Male mature nymph (mounted on slides, medium Euparal), Colombia, Meta, Castilla La Nueva, Vereda Cacayal , Río Orotoy , 3°52’9.0” N, 73°38’18.6” W, 419m, 02/vi/2011, Osorio D, Caro C, cols ( CEBUC) . Paratypes: fourteen mature nymphs (four specimens mounted on slides, medium: Euparal), same data as holotype (seven specimens deposited in CEBUC and seven specimens deposited in MIUQ) .

Additional material: 35 nymphs, same data as holotype deposited in MIUQ .

Habitat ( Fig. 13 ). The nymphs were collected from the Río Orotoy, which is in the Orinoco River basin. The stream is meandering and open, with clear water. It is 20 m wide, has an average depth of 0.68 m and discharge of 2.7 m 3 /s for the sampling season (high water). The stream bed is composed of boulders and sandy clay substrate. The riverbank presents secondary vegetation, typical of a foothill forest. The water temperature was 25°C; pH was 6.4 units; dissolved oxygen content was high (9.0 mg/l), conductivity was low (16 μS/cm).

Figures

FIGURE 1. Camelobaetidius metae sp. nov., nymph.

FIGURES 2–6. Camelobaetidius metae sp. nov., nymph. 2, labrum (left v.v., right d.v.). 3, hypopharynx. 4, left mandible. 4a, incisors and prostheca of left mandible. 5, right mandible. 5a, incisors and prostheca of right mandible. 6, maxilla.

FIGURES 7–11. Camelobaetidius metae sp. nov., nymph.7, labium (left v.v., right d.v.). 8, foreleg. 8a, detail of tarsal claw. 9, posterior margin of terga IV. 10, gill IV. 11, paraproct.

FIGURE 12. Geographic distribution of Camelobaetidius metae sp. nov. in Colombia.

FIGURE 13. General aspect of Camelobaetidius metae sp. nov. habitat.