A new species of Americabaetis (Ephemeroptera: Baetidae) from Itatiaia National Park, Brazil

ABSTRACT

A new species of Americabaetis Kluge, 1992 is described based on nymphs and subimagos from Itatiaia National Park, close to the border of Minas Gerais and Rio de Janeiro, Brazil. The new species can be differentiated from the remaining species of the genus based on the following combination of characteristics: (1) frontal keel present, (2) right mandible with angle between incisors and mola obtuse, (3) paraglossa nearly twice longer than wide, (4) fore femur with 40-42 long, apically acute, simple setae in outer margin, (5) gills grayish with pigmented tracheation, (6) distinctive abdominal color pattern (two white posterolateral spots on abdominal terga IV and VII, white medial band running along abdominal terga, and lateral margins washed with brown), (7) posterior margin of abdominal terga with triangular spines, and (8) paraproct marginally with 12-14 spines. Given the development of the labial palp segment III, shape of the apex of the lingua, and robustness of the body, the new species is somewhat similar to A. labiosus and A. titthion. It can be readily distinguished from A. titthion by the absence of meso and metasternal projections and by the shape of spines on the posterior margin of abdominal terga (triangular on the new species, blunt on A. titthion). The main differences between the new species and A. labiosus are the paraglossa length/width ratio (2.3x in the new species, 2.5x in A. labiosus), the relative length of the maxillary palp (longer than galea-lacinia in the new species versus subequal in A. labiosus), as well as pigmentation of tracheae on gills (which is absent in A. labiosus). The abdominal color pattern of A. itatiaia sp. nov. is also very distinctive in relation to A. labiosus and A. titthion.

KEY WORDS:
Baetinae; Insecta; Neotropic; taxonomy