Apobaetis trivellae, 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 : 96-100

Apobaetis trivellae sp. nov.

( Figures 4–6 )

Material examined. Holotype. Male nymph (on slide), BRAZIL, Amapá, Oiapoque , BR 156 , 51º49′55.7″ W, 03º50′38.4″ N, 10.viii.2011, colls. Pes, A., Cruz, P., Fernandes, A. and Hamada, N., INPA.

Description. Mature male nymph. Body: 2.2 mm (4A–C). Head. Coloration: cream. Antennas broken. Labrum ( Figs. 5A– B ). Length 0.5× maximum width; distal medial margin straight; dorsal surface with 3–4 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. 5C ). Outer and inner set of incisors with 4 and 3 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 3 prominent denticles; lateral margin convex. Right mandible ( Fig. 5D ). Outer and inner set of incisors with 3 and 2 denticles respectively; prostheca slender, bifid at apex, pectinated on outer margins; margin between prostheca and mola concave; tuft of setae at base of mola absent; denticles of mola not constricted; lateral margin convex. Hypopharynx ( Fig. 5E ). 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. 5F ). Maxillary palp long, 2.2× length of galea-lacinia, narrow from base to apex; segment I 0.8× length of galea-lacinia; segment II with thin and simple setae over surface, apex without constriction. Labium ( Fig. 5G– H ). Glossa robust from apex to base, subquadrangular at apex, longer than paraglossa, inner margin without setae; dorsal surface with 1 minute spine-like setae near inner margin, 2 short spine-like setae and 2 thin and simple setae on apex ( Fig. 5H ); one longitudinal row of 6 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 11 long spine-like setae on apical half on outer margin and one longitudinal row of 6 robust and long spine-like setae on apical half near inner margin; ventral surface with one longitudinal row of 7 long and robust spine-like setae on apical half at middle. Labial palp with segment I robust, 0.8× 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, laterally directed; ventral surface of distomedial projection with tuft of thin, long and simple setae; segment III rectangular, with distal margin concave, length 0.4× width, covered by thin, long and simple setae on outer margin, dorsally with one row of 11 robust spine-like setae in different sizes near distal margin, ventrally with one row of 8 robust spine-like setae in different sizes near distal margin. Thorax. Pigmentation ( Figs. 4A–C ). Cream, with light brown sublateral spot on pronotum and mesonotum, light brown spot on base of forewing pads; legs with brown spot at base 1/3 apical on anterior margin of femur. Foreleg ( Figs. 6A–B ). Femur. Dorsal surface with one row of 8 short, concave and blunt setae; apex with 2 short, concave and blunt setae; anterior surface with one row of 5 short and concave setae on basal third; ventral margin with one row of 9 spine-like setae in different sizes; posterior surface with one row of 9 spine-like setae in different sizes near ventral margin. Tibia. Dorsal margin bare; ventral margin with one row of 13 spine-like setae. Patella-tibial suture present, restricted to ventral margin. Tarsus. Dorsal margin bare; ventral margin with one row of 14 spine-like setae. Tarsal Claw. 0.8× length of tarsus, row of denticles absent. Middle and hind legs similar to foreleg. Abdomen. Pigmentation ( Figs. 4A–C ). Cream, tergum II with medial brown mark; tergum V with lateral brown mark; sterna I–VIII with anterolateral brown mark; sternum IX with brown mark on anterior margin. Terga ( Fig. 6C ). Sculpting of abdominal terga in form of shallow triangular scale-like; tergal surface covered by micropores. Tergum IV ( Fig. 6C ). Posterior margin with triangular pointed spines longer than wide. Gills ( Fig. 6D ). Triangular apex, conspicuous trachea; long, extending to beginning of third subsequent tergum. Paraproct ( Fig. 6E ). Eleven marginal spines; posterolateral extension without spines. Cerci ( Fig. 6F ). Lateral short spines on all segments. Paracercus ( Fig. 6G ). Lateral short spines on alternate segments.

Imago: Unknown.

Etymology. The specific name is a tribute to Dr Daniela Trivella, a scientific coordinator of the Laboratório Nacional de Biociências do Centro Nacional de Pesquisa em Energia e Materiais (LNBio-CNPEM) from São Paulo. During the pandemic, she coordinated the COVID-19 task force, which included studies of SARS-CoV-2 of proteins. Noun in the genitive case

Diagnosis. Mature nymph. 1) Distal medial margin of labrum straight ( Fig. 5A ); 2) dorsal surface of labrum with 3–4 short and blunt medial setae near distal margin ( Figs. 5A–B ); 3) lingua subquadrangular, apical tuft of setae present, length subequal to superlingua ( Fig. 5E ); 4) maxillary palp long, 2.2× length of galea-lacinia; segment II slender from base to apex, without apical constriction ( Fig. 5F ); 5) segment II of labial palp with triangular and elongated distomedial projection; segment III subretangular, with distal margin concave ( Fig. 5G ); 6) glossa robust, from apex to base, subquadrangular at apex, longer than paraglossa ( Fig. 5G ); 7) dorsal margin of foreleg with one row of 8 short, concave and blunt setae of femur; 8) claw 0.8× length of tarsus, without row of denticles ( Figs. 6A–B ); 9) posterior margin of tergum IV with triangular pointed spines, longer than wider ( Fig. 6C ); 10) paraproct with several marginal spines, posterolateral extension without spines ( Fig. 6E ).

Figures

FIGURE 4. Apobaetis trivellae sp. nov., habitus of nymph. A. male nymph (d.v.). B. male nymph (l.v.). C. male nymph (v.v.).

FIGURE 5. Apobaetis trivellae 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 6. Apobaetis trivellae sp. nov. Holotype, thorax and abdomen of nymph. A. foreleg (femur on anterior surface). B. detail of setae on anterior surface of forefemur, setae on posterior surface dotted. C. posterior margin of tergum IV. D. gill. E. paraproct. cercus. F. cercus. G. paracercus.