Mammals Of The Rio Juruá And The Evolutionary And Ecological Diversification Of Amazonia Author PATTON, JAMES L. Author DA SILVA, MARIA NAZARETH F. Author MALCOLM, JAY R. text Bulletin of the American Museum of Natural History 2000 2000-01-25 2000 244 1 306 http://www.bioone.org/perlserv/?request=get-abstract&doi=10.1206%2F0003-0090(2000)244%3C0001%3AMOTRJA%3E2.0.CO%3B2 journal article 10.1206/0003-0090(2000)244<0001:MOTRJA>2.0.CO;2 0003-0090 5347311 Marmosops parvidens (Tate, 1931) TYPE LOCALITY: ‘‘Hyde Park, 30 miles up the Demarara River, British Guiana , alt. 20 feet ,’’ East Demerara–West Coast Berbice Guyana . DESCRIPTION: This is the smallest species in the Amazon region, with a total length of 218 mm , condyloincisive length of the skull not exceeding 25.9 mm, and adult weight less than 25 g . The molar teeth are small (mean maxillary toothrow length = 10.8 mm; M1–M4 length = 5.6 mm; table 8), the interorbital region is smooth and rounded in transverse section, with virtually no hint of supraorbital beading even in the oldest individuals. The palate lacks posterior vacuities, and the anterior pair are greatly reduced in size in comparison to the condition in the other three species. The coloration above is dark grayish­brown (Mummy Brown; Ridgway, 1912) as in M . neblina ; below the venter is white along the midline with wide marginal bands of gray­based and silver­tipped hairs constricting the medial white, especially in the abdominal and inguinal region. COMPARISONS: This species is readily distinguishable by its overall small size, lack of supraorbital beading even in old adult individuals, and lack of posterior palatal vacuities. It is similar in general coloration above and below with M . neblina , and indeed it looks like a miniature version of this species such that live specimens could be readily confused. DISTRIBUTION AND HABITAT: We collected this species only at localities in our Lower Central and Mouth sampling regions along the Rio Juruá (fig. 1), where it was always found in terra firme forest, two individuals on the ground and four at heights of 1.5 to 2 m . REPRODUCTION: We caught this species only in the months of October, April, May, and June. The three juveniles were collected at the end of the wet season in May and June; no adult females were found with attached young. COMMENTS: The molecular data summarized in fig. 43 and evidence for sympatry in French Guiana of recognizable morphological entities (Robert S. Voss, personal commun.) underscore the composite nature of M . parvidens sensu Pine (1981) . Since the type locality for M . parvidens is on the coast in Guyana , it is likely that another species name should be applied to our specimens from the Rio Jurua´. We defer from making such a decision here, however, as we have not had the opportunity to examine specimens of appropriate candidate taxa. SPECIMENS EXAMINED (n = 7): ( 12 ) 1m — JLP 15826; ( 13 ) 1m — JUR 476; ( 14 ) 1f, 2m — JUR 435–437; ( 15 ) 1f — JUR 381; ( 16 ) 1f — MNFS 1757. METACHIRUS BURMEISTER, 1854