O / "7". L^ ^ / ZJ Vol. 68, pp. 83-86 August 3, 1955 PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON TWO NEW RICE RATS (GENUS 0RYZ0MY8) FROM ||^ ^ Si FLORIDA By W. J. Hamilton, Jr., Cornell University Among a series of small mammals collected in Lee County, Florida during the late winter and early spring of 1954, 26 Oryzomys were taken on Pine and Sanibel Island. The speci-mens from both of these islands are markedly distinct, both in color, in size and skull characters, from Oryzomys palustris natator and Oryzomys palustris coloratus and may be con-sidered subspeeifically distinct. Oryzomys palustris planirostris, new subspecies Type. — Adult female, skin and skull, number 8090, Cornell University Mammal Collection, collected one mile west of third bridge that spans Matachla Pass, Pine Island, Lee County, Florida, by W. J. Hamilton, Jr., March 11, 1954; original number 4344. The type has the following measurements: Total length, 240; tail vertebrae, 122; hind foot, 32; weight 50.5 grams. Skull: condylobasal length, 30.0; zygomatic breadth, 15.5; cranial breadth, 13.7; nasals, 12.0; interorbital breadth, 5.8; anterior palatine foramen, 6.7; palatal bridge, 6.0; upper molar series, 4.7. Bange. — Known only from Pine Island and an area two miles north of Fort Myers, Florida. Diagnosis. — Size small (Table 1). Winter pelage, upperparts brownish gray, top of head and mid-dorsum darker with slightly buffy suffusion on sides and flanks, the buff color scarcely marked in some individuals ; underparts dull white; feet white, tail dark gray above, whitish below. Color similar to Georgia and Virginia specimens of 0. p. palustris, but with a browner caste. Skull small and weak, the supraorbital and tem-poral ridges much less pronounced than in natator or coloratus; ros-trum relatively short and broad; anterior dorsal profile of skull straight, the nasals and frontals aligned, contrasting to the convex profile of natator and coloratus. Comparisons. — Oryzomys palustris planirostris most nearly approxi-mates in color and size Oryzomys p. palustris. It differs from botli natator and coloratus in smaller size, lack of tawny coloration and the smaller and weaker skull characters. Remarlcs. — Twelve specimens were collected in a garbage dump and adjoining wet land (about five feet above tide level, at the type locality). In company with Sigmodon hispidus insullicola, these animals were utilizing the cover formed by tin cans, cardboard cartons and other detritus. Traps placed in well marked runways took both species, as did those set in dense stands of Spartina patens well removed from the 13— Proc. Rioi,. Soc. Wash., Vol. 68, 1955 (83)
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