Portal de Periódicos da CAPES

Behavior, Vocalizations, and Relationships of Some Myrmotherula antwrens (Thamnophilidae) in Eastern Brazil, with Comments on the "Plain-Winged" Group

1997; Issue: 48 Linguagem: Inglês

10.2307/40157569

1941-2282

Bret M. Whitney, José Fernando Pacheco,

Animal Behavior and Reproduction

unicolor (Unicolored Antwren), snowi (Alagoas Antwren), and urosticta (Band-tailed An- twren). Application of these data in intrageneric comparisons suggests that minor is most closely related to M. schisticolor (Sla W Antwren) and M. sunensis (Rio Suno Antwren) and that unicolor is a member of the plain-winged group, which we suggest is mono- phyletic, including M. behni (Plain-winged Antwren), M. grisea (Ashy Antwren), and M. snowi. Based on significant heterogynism and external morphological distinctions and, to a lesser extent (owing to inadequate and ambiguous samples of songs), vocal differences, we recommend that snowi, originally described as a subspecies of unicolor, be elevated to species rank. M. urosticta is the Atlantic Forest representative of the widespread urostictaJ longipennis (Long-winged Antwren) complex. We discuss the concept that foraging data sets must be quantified to be comparable or applicable in systematic revision. Rv_sumo.---Descrevemos os hfibitos de forrageamento e vocalizaq6es de quatro esp6cies do ggnero Myrmotherula endgmicas ao bioma brasileiro da Mata Atlfintica: minor, unicolor, snowi e urosticta. A aplicaqo desses dados em comparaq6es intragen6ricas sugere que M. minor 6 mais proximamente relacionada a M. schisticolor e M. sunensis e que M. unicolor 6 membro do grupo de esp6cies de asas-lisas - o qual sugerimos considerar monofi16tico - incluindo M. behni, M. grisea e M. snowi. Baseado na significante heteroginia e diferenqas morfo16gicas externas e, em menor extenso (considerando que a amostra existente 6 inadequada e ambfgua), diferenqas no repert6rio vocal, recomendamos que M. snowi, or- iginalmente descrita como subesp6cie de M. unicolor, seja elevada ao nfvel de esp6cie. M. urosticta 6 o representante na Mata Atlfintica do - bern espalhado - complexo urostictaJ longipennis. Discutimos o conceito que dados de forrageamento devem ser quantificados para ser comparfiveis ou aplicfiveis em revises sistenuiticas. As currently treated (e.g., Sibley and Monroe 1990), the thamnophilid genus Myrmotherula is represented in the Atlantic Forest of Brazil by six species: gularis (Star-throated Antwren), axillaris (White-flanked Antwren), fiuminensis (Rio de Janeiro Antwren, known only from the unique type), minor (Salvadori's Antwren), unicolor (Unicolored Antwren), and urosticta (Band- tailed Antwren). All but axillaris and minor are considered to be endemic to the region. However, clear distinctions in the morphology and vocalizations of the disjunct, endemic subspecies luc- tuosa of M. axillaris indicate that it is best regarded as a separate species (Isler et al. 1997), and Whitney and Pacheco (1995) restricted M. minor to the Atlantic Forest as well. Additionally, the isolated subspecies snowi of M. unicolor appears to merit recognition as a distinct species (see below). In this paper, we present the first substantive descriptions of the foraging behavior and vocalizations of four of these endemic Myrmotherula (minor, unicolor, snowi, and urosticta), and apply these data to suggest species relationships. We provide evidence to suggest that the plain-winged antwrens (as defined below) form a monophyletic group. The distribution, habitat, and conservation status of these species were reported by Whitney and Pacheco (1995). Myrmotherula minor, M. unicolor, and M. urosn'cta are lowland species, with distributions centered in undisturbed forest between sea level and about 500 m elevation.