Apobaetis dalcolmoae, De Lima & Cruz & Hamada, 2024

De Lima, Claudia R. T., Cruz, Paulo Vilela & Hamada, Neusa, 2024, Five new species of Apobaetis Day (Ephemeroptera: Baetidae) and updated key to nymphs, Zootaxa 5397 (1), pp. 91-115 : 100-104

Apobaetis dalcolmoae sp. nov.

( Figures 7–9 )

Material examined. Holotype. Famale nymph (on slide), BRAZIL, Roraima, Pacaraima, Rio Ereu , 04º02′02.9″ N, 61º23′09.5″ W, 26.iii.2012, Colls. Hamada, N., Cruz, P., Dantas, G. and Boldrini, R., INPA . Paratype: Nymph (on slide), same data as holotype, INPA .

Description. Mature female nymph. Body: 2.8–3.1 mm (7A–C). Head. Coloration: cream. Antenna. Flagellum with minute spines on apex of each flagellomere. Labrum ( Figs. 8A–B ). Length 0.6× maximum width; distal medial margin slightly concave; dorsal surface with 2 short and blunt medial setae near distal margin, one row of long, thin, and simple setae arranged parallel to the distal margin and long, thin and simple setae scattered over all surface; ventral surface with one row of robust spine-like setae on distolateral and distal margins. Left mandible ( Fig. 8C ). Outer and inner set of incisors with 4 and 2 denticles, respectively; prostheca robust, bifid at apex, outer lobe robust, inner lobe slender with a medial tuft of setae; margin between prostheca and mola concave, wide subtriangular process, with short protuberance on distal margin; tuft of setae at base of subtriangular process; denticles of mola not constricted, with 4 prominent denticles; lateral margin convex. Right mandible ( Fig. 8D ). Outer and inner set of incisors with 3 and 2 denticles, respectively; prostheca slender, bifid at apex; margin between prostheca and mola concave; tuft of setae at base of mola absent; denticles of mola not constricted; lateral margin convex. Hypopharynx ( Fig. 8E ). Lingua subquadrangular, apex covered by tuft of short setae, length subequal to superlingua; superlingua oval not expanded, with short and thin setae on distolateral and distal margin. Maxilla ( Fig. 8F ). Maxillary palp long, 2.0× length of galea-lacinia; segment I robust, subequal to galea-lacinia; segment II robust from base to apex, with thin and simple setae over surface, apex without constriction. Labium ( Fig. 8G–H ). Glossa slender, apically round, progressively narrowing towards the base, longer than paraglossa; dorsal surface with one longitudinal row of 3 short spine-like setae on apical third, near inner margin, and 1 thin and simple setae on apex ( Fig. 8H ); one longitudinal row of 8 robust spine-like setae on apical half, near outer margin; ventral surface covered by long, thin, and simple setae. Paraglossa curved inward; dorsal surface with one longitudinal row of 10 long spine-like setae on apical half on outer margin and one longitudinal row of 5 long and robust spine-like setae on apical half near inner margin; ventral surface with one longitudinal row of 5 long and robust spine-like setae on apical half at middle. Labial palp with segment I robust, 0.6× length of segments II and III combined, covered by micropores (not illustrated); segment II with outer margin covered by thin, long and simple setae, inner margin bare; distomedial projection of segment II triangular and elongated, 1.2× longer than segment III, apically directed; ventral surface of distomedial projection covered by long, thin, and simple setae; segment III rectangular, with straight distal margin, length subequal wide, covered by thin, long and simple setae on outer margin, dorsally with one row of 11 to 14 spine-like setae in different sizes near distal margin, ventrally with one row of 10 to 12 spine-like setae in different sizes near distal margin. Thorax. Pigmentation ( Figs. 7A–C ). Cream, with light brown sublateral spot on pronotum; light brown spot over mesonotum; light brown forewing pads; legs with brown spot at base 1/3 apical on anterior margin of femur. Foreleg ( Figs. 9A–B ). Femur. Posterior surface with one row of 6 to 8 minute and blunt setae near dorsal margin; ventral margin with one row of 6 to 8 spine-like setae in different sizes. Tibia. Dorsal margin bare; ventral margin with one row of 7 to 8 spine-like setae. Patella-tibial suture present, from dorsal to ventral margin. Tarsus. Dorsal margin bare; ventral margin with one row of 8 to 9 spine-like setae. Tarsal claw. 0.6–0.8× length of tarsus, row of denticles absent. Middle and posterior leg similar to foreleg. Abdomen. Pigmentation ( Figs. 7A–C ). Cream, terga II and III with medial brown mark; tergum V with sublateral brown mark; tergum IX almost completely covered by light brown spot; lateral mark view dorsoventrally on terga II from terga VIII; sterna VI and VIII with antero-sublateral brown mark; sternum IX with brown mark on anterior margin. Terga ( Fig. 9C ). Sculpting of abdominal terga in form of triangular scale-like; tergal surface covered by micropores. Tergum IV ( Fig. 9C ). Posterior margin with triangular spines in irregular apex and sizes. Gill ( Fig. 9D ). Triangular apex, conspicuous trachea; long, extending to beginning of third subsequent tergum. Paraproct lost. Cerci ( Fig. 9E ). Lateral short spines on all segments; light brown mark in three consecutive segments, alternating on all extension. Paracercus ( Fig. 9F ). Lateral short spines on all segments.

Imago: Unknown.

Etymology. The specific name is a tribute to the researcher Dr. Margareth Dalcolmo. Winner of the Jabuti Award (the most traditional literature award in Brazil) in the Science category with the book: ‘ Um tempo para não esquecer: a visão da ciência no enfrentamento da pandemia do coronavírus e o futuro da saúde. ’ Noun in the genitive case.

Diagnosis. Mature nymph. 1) Distal medial margin of labrum slightly concave ( Figs. 8A ); 2) dorsal surface of labrum with 2 short and blunt medial setae near distal margin ( Figs. 8A–B ); 3) lingua subquadrangular, apical tuft of setae present, length subequal to superlingua ( Fig. 8E ); 4) maxillary palp long, 2.0× length of galea-lacinia; segment II without apical constriction ( Fig. 8F ); 5) segment II of labial palp with triangular and elongated distomedial projection, 1.2× longer than segment III; segment III retangular, with straight distal margin ( Fig. 8G ); 6) glossa slender, apically round, progressively narrowing towards the base, longer than paraglossa ( Fig. 8G ); 7) posterior surface of foreleg with one row of 6 to 8 minute and rounded setae near dorsal margin of femur ( Fig. 9A–B ); 8) claw 0.6–0.8× length of tarsus, without row of denticles ( Figs. 9A ); 9) posterior margin of tergum IV with triangular spines in irregular apex and sizes ( Fig. 9C ).

Figures

FIGURE 7. Apobaetis dalcolmoae sp. nov., habitus of nymph. A. female nymph (d.v.). B. female nymph (l.v.). C. female nymph (v.v.).

FIGURE 8. Apobaetis dalcolmoae sp. nov. Holotype, mouthparts of nymph. A. labrum (left d.v., right v.v). B. detail of blunt medial setae near to distal margin on dorsal surface of labrum. C. left mandible. D. right mandible. E. hypopharynx. F. maxilla. G. labium (left d.v., right v.v.). H. detail of setae on apex of glossa (d.v.).

FIGURE 9. Apobaetis dalcolmoae sp. nov. Holotype, thorax and abdomen of nymph. A. foreleg (femur on anterior surface), setae on posterior surface dotted. B. detail of setae on posterior surface of forefemur. C. posterior margin of tergum IV. D. gill. E. cercus. F. paracercus.