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Observations on the Systematics, Behavior, and Vocalizations of "Thamnomanes" occidentalis (Formicariidae)

1992; Oxford University Press; Volume: 109; Issue: 2 Linguagem: Inglês

10.2307/4088198

1938-4254

Bret M. Whitney,

Ecology and Vegetation Dynamics Studies

-In January 1991 I rediscovered Thamnomanes occidentalis in eastern Ecuador, following a period of more than 50 years without a record. I review its controversial taxonomic history and, based upon observations of its behavior and vocalizations, suggest that occidentalis be reinstated in the genus Dysithamnus. Received 1 April 1991, accepted 10 January 1992. THAMNOMANES OCCIDENTALIS, the Western Antshrike, has a confused taxonomic history at both the specific and generic levels. It is known from only two small areas on opposite sides of the northern Andes. These two populations currently are regarded as conspecific, but generic affinities remain obscure. Known from but nine specimens, T. occidentalis has not been recorded for more than 50 years, and there is no account of it in life. In part due to taxonomic confusion that stems from the earliest descriptions of its two subspecies, the literature summarizing the distribution and elevational range of T. occidentalis (Hilty and Brown 1986, Ortiz et al. 1990) is inaccurate with regard to the Ecuadorian subspecies punctitectus. I provide the first information on the behavior and vocalizations of T. occidentalis, which allows a reassessment of the generic alignment of this elusive antbird of the subtropical forests of the northern Andes. SUMMARY OF RECORDS AND DISTRIBUTION Nominate occidentalis is known only from the Department of Cauca, Colombia, on the west slope of the Western Andes in the vicinity of Munchique. There are four specimens: one male from the type locality Cocal, 4000 feet in the American Museum of Natural History (AMNH; R. Sloss, pers. comm.); one female from Rio Munchique, El Tambo, 3000 feet in the Academy of Natural Sciences (M. Robbins, pers. comm.); and one male and one specimen with sex unknown from La Costa, 1100-1200 m in the Swedish Museum of Natural History (Gyldenstolpe 1941). The subspecies punctitectus is known from five specimens taken within a small area of Napo Province, Ecuador: two males and one female from the type locality Oyacachi, abajo, Chaco (Ecuador) in the AMNH (R. Sloss, pers. comm.); one male from Abajo (Ecuador) in the AMNH (Chapman 1926; R. Sloss, pers. comm.); and one male reportedly from Baeza in the British Museum (T. Schulenberg, pers. comm.). The localities San Jose, Sarayacu, Zamora listed for punctitectus by Hilty and Brown (1986) apparently are in error, as I am not able to find any specimens or reference in the literature to substantiate them. Hilty and Brown (1986) stated the elevational range of punctitectus as 500-1,000 m, but based upon my field experience and the published elevational data for all known localities of collection (Chapman 1926, Paynter and Traylor 1977), I believe that all records are from above at least 1,500 m. Most of the type locality and much of the suitable habitat within the small known range of this subspecies, with the notable exceptions of Mt. Sumaco and portions of Huacamayo Ridge, have been deforested (pers. observ.).