University of Kansas Publications
Museum of Natural History
Volume 5, No. 24, pp. 313-317
November 21, 1952
University of Kansas
LAWRENCE
1952
University of Kansas Publications, Museum of Natural History
Editors: E. Raymond Hall, Chairman, A. Byron Leonard,
Edward H. Taylor, Robert W. Wilson
Volume 5, No. 24, pp. 313-317
November 21, 1952
University of Kansas
Lawrence, Kansas
PRINTED BY
FERD VOILAND, JR., STATE PRINTER
TOPEKA, KANSAS
1952
25-4545
New name combinations for two kinds of Central American sloths thatheretofore have stood in the literature as nominal species are givenbelow, along with the evidence supporting their relegation tosubspecific rank. Research assistance has been provided from a contract(NR 161-791) between the Office of Naval Research, Department of theNavy, and the University of Kansas.
Bradypus griseus ignavus Goldman
Goldman (Smiths. Misc. Coll., 60(22):1, February 28, 1913) named thethree-toed sloth from extreme eastern Panamá (Marraganti: 1 specimen,the type) and northwestern Colombia (Atrato River: 2 specimens) asBradypus ignavus. He characterized the newly-named species asdiffering from Bradypus griseus (type locality Cordillera de Chucu,Veragua, Panamá) and Bradypus castaneiceps (type locality, Chontales,Nicaragua) in "nasals shorter, with anterior border concave oremarginate, the emargination deepest at median suture; squamosal arm ofzygoma broader, more rounded, less acutely pointed anteriorly; palateless deeply grooved posteriorly; symphysis of mandible less producedanteriorly beyond plane of first molars." Later, Goldman (Smiths. Misc.Coll., 69(5):57-58, April 24, 1920) arranged Bradypus castaneiceps asa subspecies of B. griseus, reaffirmed the full specific identity ofBradypus ignavus, and identified specimens from Tapalisa, Cituro, andReal de Santa Maria, all in eastern Panamá, as belonging to B.ignavus.
In order to satisfy ourselves about the taxonomic relationship of B.ignavus to B. griseus, we have examined the following materials inthe American Museum of Natural History: ignavus: Panamá: Cituro (No.38191), Tapalisa (No. 38102), Real de Santa Maria (Nos. 37619-37621);griseus: Panamá: La Chorrera (No. 31427); Costa Rica: Juan Viñas (No.2824), Palmar (No. 139313), Vijagual, San Carlos (No. 139833);castaneiceps: Nicaragua: Chontales (Nos. 28477 and 28478).[Pg 316]
The specimens from Real de Santa Maria, Tapalisa, and Cituro, averagedarker than all others, but this darkness is approached in certainspecimens of griseus (for example, No. 139833, from Vijagual, SanCarlos). The broader, more rounded and less acutely pointed squamosalarm of the zygoma supposedly characteristic of ignavus is matched incertain specimens of griseus (for example, in No. 2824 from JuanViñas, Costa Rica) and the character is variable among specimensreferred to ignavus; the shape of the squamosal arm is of doubtfultaxonomic worth in the present connection. The depth of the grooving onthe palate seems to vary with age and is of questionable valuetaxonomically. The emarginate nasals of ignavus are matched ingriseus (No. 139833) from Vi