Americabaetis longetron Lugo-Ortiz & McCafferty, 1996

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 : 25-26

Americabaetis longetron Lugo-Ortiz & McCafferty, 1996

( Figs. 1d , 19, 22, 26 , 28 )

Americabaetis longetron Lugo-Ortiz & McCafferty, 1996: 165 ; Francischetti et al., 2003: 69; Domínguez et al., 2006: 70; Salles & Boldrini, 2008: 565; Salles et al., 2010: 302 .

Diagnoses. Nymphs: 1) frontal keel present; 2) lingua rounded apically; 3) glossa 0.8x length of paraglossa; 4) apex of paraglossa with rows of simple setae; 5) segment II of labial palp with a strong distomedial projection; 6) posterior margin of abdominal terga with pointed spines; 7) abdomen elongate.

Male imago: 1) turbinate eyes uniformly separated from each other, upper surface ellipsoidal; 2) terga with a light yellowish brown band along midline; 3) forceps with first segment distinctly constricted medioapically; 4) posterior margin of subgenital plate without a small rounded projection; 5) length of body relatively long (6.3 mm).

Distribution. PARAGUAY, URUGUAY, BRAZIL: Rio Grande do Sul, Paraná, Santa Catarina; Rio de Janeiro, Espírito Santo, Minas Gerais, São Paulo ( Fig. 1c ).

Comments. Nymphs of A. longetron are present almost exclusively in banks with marginal vegetation in areas with slow to moderate current; they resemble A. alphus in several aspects, as mouthpart morphology and somewhat similar habitat ( Fig. 28 ). However, the distribution of A. longetron is far restricted when compared to that of A. alphus . The altitudinal range of this species varies from 371 to 1063 m.a.s.l.

Material examined. ESPÍRITO SANTO, Santa Teresa, Nova Lombardia, Sítio Capitel de Santo Antônio , Pinguela , S 19°52’16.0” / W 40°31’43.3”, 718 m. a.s.l., 18/ii/2009, pedra em remanso, FFS col. ( CEUNES) ; ESPÍRITO SANTO, Caparaó, Sítio Sonho Meu , S 20°28’08,8’’ / W 41°43’32,5’’, 1063 m.a.s.l., 21/iv/2008, vegetação marginal, FFS col. ( CEUNES) .

Figures

FIGURE 1. Distribution of the species of Americabaetis in Brazil. Fig. 1b, map of Brazil; Figs. 1a, c–e, partial map of Brazil. a) A. mecistognathus, sp. nov.; b) A. alphus; c) A. labiosus; d) A. longetron; e) A. titthion. (Question mark indicates that a species is reported to a state, but the exact location is unknown; grey mark indicates record based on literature, white mark indicates new record. AL, Alagoas; BA, Bahia; ES, Espírito Santo; GO, Goiás; MG, Minas Gerais; MT, Mato Grosso; PR, Paraná; RJ, Rio de Janeiro; RS, Rio Grande do Sul; SC, Santa Catarina; SE, Sergipe; SP, São Paulo).

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.

FIGURES 27–30. General aspect of Americabaetis nymphs’ habitat. 27. A. mecistognathus, sp. nov.; 28. A. alphus and A. longetron; 29. A. labiosus; 30. A. titthion.