2 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 139 



Genus HOPLOMYS J. A. Allen 



1908. Hoplomys J. A. Allen, Bull. Amer. Mus. Nat. Hist., vol. 24, p. 649. 



Genotype. — Hoplomys truei J. A. Allen. 



Distribution. — The genus has a limited distribution in Central 

 America and northwestern South America. It is monotypic. Published 

 records of collecting localities are mapped in figure 1. Hoplomys is 

 known to occur at medium elevations (800-3,100 ft.) on the Caribbean 

 slope of the highlands of Nicaragua and Costa Rica ; near sea level 

 on the Caribbean coast of Panama; at medium elevations (600-4,000 

 ft.) on the Pacific slope of eastern Panama, Colombia, and Ecuador; 

 and near sea level in extreme southwestern Colombia and north- 

 western Ecuador. The distribution of Hoplomys in South America 

 appears to be limited by the Western Andes. J. A. Allen's record for 

 Puerto Valdivia on the Rio Cauca (Bull. Amer. Mus. Nat. Hist., 

 vol. 35, p. 207, 1916) is erroneous (the specimen is a Proechimys). 

 Proechimys cayennensis hoplomyoides Tate (Bull. Amer. Mus. Nat. 

 Hist., vol. j6, p. 179, 1939) from Mt. Roraima, Venezuela, appears 

 not to be a Hoplomys, although a relationship has been suggested 

 (Moojen, Univ. Kansas Publ., Mus. Nat. Hist., vol. i, p. 324, 1948). 



In the Caribbean lowlands of Panama, where Proechimys is abun- 

 dant and Hoplomys seemingly rare, I have trapped individuals of 

 both genera under the same log on successive nights. At medium alti- 

 tudes in the mountains of Panama where Hoplomys is fairly common, 

 Proechimys apparently does not occur. 



All the Hoplomys that I have collected in Panama were caught in 

 banana-baited live traps under large decaying logs — in fairly open 

 mature rain forest, in grassy clearings and adjacent streamside 

 thickets, and in dense, hillside Heliconia thickets. Goldman (Smith- 

 sonian Misc. Coll., vol. 69, No. 5, p. 124, 1920) found Hoplomys 

 associated with fallen trees and rocks in Panamanian forests. 



Diagnosis. — Dorsum, flanks, and rump, in both adult and juvenile 

 pelages, with spines 26 to 33 mm. in maximum length and 1.5 to 2.0 

 mm. in maximum diameter, tending to obscure soft fur. Tail shorter 

 than head and body, scaly, and sparsely haired. Ears scantily haired. 

 Hind feet long and narrow ; fifth toe scarcely longer than first ; claws 

 relatively straight, but claw of second toe slightly expanded. Skull 

 prominently ridged, and supraorbital shelf beaded ; rostrum relatively 

 broad at tip ; auditory bullae relatively small ; and infraorbital foramen 

 without subsidiary canal on floor, and with external wall thin in 

 lateral view. Cheek teeth with oblique folds ; counterfold formula 

 normally 4/4-4/4-4/4-4/4, rarely 4/4-4/3-4/3-4/3. 



