Americabaetis Kluge, 1992

Salles, F. F., Raimundi, E. A., Boldrini, R. & Souza-Franco, G. M., 2010, The genus Americabaetis Kluge (Ephemeroptera: Baetidae) in Brazil: new species, stage description, and key to nymphs, Zootaxa 2560 (1), pp. 16-28 : 17

Americabaetis Kluge, 1992

Baetis (Americabaetis) Kluge, 1992: 18 .

Genus 1 nr Pseudocloeon Roback, 1966: 134 .

Acerpenna Waltz & McCafferty , in part: Lugo-Ortiz & McCafferty, 1994: 66.

Americabaetis Lugo-Ortiz & McCafferty, 1996: 157 ; Lugo-Ortiz & McCafferty, 1999: 260; Domínguez et al., 2006: 66.

Diagnoses. The genus was adequately characterized by Lugo-Ortiz and McCafferty (1996) and later by Domínguez et al. (2006). Herein we add one important character regarding the nymphal stage which has been observed in all Brazilian species as well as in an unidentified species from Central America: the shape of the lateral branch of the epicranial suture. In most baetids they are straight or curved, while in Americabaetis they are sinuous, somewhat similar to those of the genus Baetodes Needham & Murphy , and can be very useful when identifying nymphs of the family (see Figs. 2 , 18 and 19 ). Other characteristic that can be emended to the nymphal diagnoses is the presence of scales and/or scale bases over body.

Nymphs (modified from Domínguez et al. 2006): 1) Lateral branch of epicranial suture sinuous; 2) mandibles with setae between prostheca and mola, incisors fused apically, and prostheca robust with denticles apically; 3) maxillary palp two-segmented; 4) glossa with a row of long spine-like setae, paraglossae rectangular with 3 rows of long spine-like setae, segment II of labial palp with a distomedial projection; 5) tarsal claws with a single row of denticles; 6) hind wing pads absent; 7) abdominal gills present on segment II–VII; 8) scales and/or scale bases over body.

Male imagos (modified from Domínguez et al. 2006): 1) Dorsal portion of turbinate eyes ellipsoidal; 2) forewings with paired (seldom single) marginal intercalary veins; 3) hind wings absent; 4) genitalia with forceps three-segmented, segment III elongate.

Figures

FIGURES 2–8. Americabaetis mecistognathus, sp. nov. Nymph. 2. Head (f.v.); 3. Labrum (left d.v., right v.v.); 4a. Left mandible (d.v.); 4b. Left mandible, detail of incisors and prostheca; 5a. Right mandible (d.v.); 5b. Right mandible, detail of incisors and prostheca. 6. Hypopharynx (d.v.); 7. Maxilla (v.v.); 8. Labium (left d.v, right v.v.).

FIGURES 18–26. Americabaetis spp. Nymph. 18. Head of A. labiosus (frontal view); 19. Head of A. longetron (f.v.); 20. Labial palp of A. alphus; 21. Labial palp of A. labiosus; 22. Abdomen in dorsal view of A. longetron; 23. Abdomen in dorsal view of A. alphus (male); 24. Abdomen in dorsal view of A. alphus (female); 25. Posterior margin of terga IV of A. labiosus; 26. Posterior margin of terga IV of A. longetron.