Some Birds of Prey from the Upper Pliocene of Kansas
Some birds of prey from the Upper Pliocene of Kansas.---Although many arian fossils from the local faunas of the Rexroad formation (Upper Pliocene), Meade County, Kansas, have now been reported, several species of birds of prey remain. These fossils, which Dr. C. W. Hibbard of The University of Michigan Museum of Paleontology a.nd his field parties collected, come from the Rexroad and Fox Canyon local faunas of the Rexroad formation. These two localities arc described by Hibbard (1950). The two local faunas have been treated as one in the past, but Hibbard's (1967) latest view is that they arc distinct. The Fox Canyon local fauna is now considered to be older than the Rexroad and is distinct on the basis of its small mammals (Hibbard, 1967). Birds have bccn reported previously from these local faunas by Wetmore (1944), Tordoff (1951, 1959), Brodkorb (1964, 1967), Collins (1964), Ford (1966), Murray (1967), a.nd Fcduccia (1967, 1968). The birds of prey represented arc as follows: Accipiter sp.---Two distal ends of tibiotarsi represent an accipitcr approximately the size of the Recent A. cooperi, but the clements arc not sufficiently diagnostic to warrant the naming of a new species or the definite assignment of the fossils to the Recent form. One bone, a 42-mm piece of the distal end of a left tibiotarsus (UMMP No. V57506, from the Rexroad local fau.na, loc. no. 3) measures 10.8 mm in width through condyles. The same measurement for eight specimens of Recent A. cooperi females gives a mcan of 10.1 mm, with a range of 9.2-10.9 mm. The smaller fossil, a 17.1-mm piece of the distal end of a left tibiotarsus (UMMP No. V45422, from the Rexroad local fauna, loc. UM-K3-53) measures 9.0 mm in width through condyles. The same measurement for five males of Recent A. cooperi gives a mean of 8.5 mm, with a range of 8.3-8.8 mm. Whether or not both fossils represent females or one a female and the other a male cannot bc dctcrmi.ned, but it is probably best to assume that only one species is represented. Buteo sp.--A fragment of a right coracold (UMMP No. V24767, from the Fox Canyon local fauna, loc. UM-K1-47) represents a large species of Buteo close in size and morphology to B. jamaicensis, but it is too fragmentary to permit allocation. No useful measurements could be taken.
Fossil Owls from the Rexroad Fauna of the Upper Pliocene of Kansas
Since 1936 field parties led by Claude W. Hibbard of The University of Michigan Museum of Paleontology have made extensive fossil collections from Upper Pliocene deposits in Meade County, Kansas, with the result that the Rexroad fauna from the Rexroad Formation, Early Blancan Age, is at present the largest known nonmarine Pliocene fauna in North America. Previous reports on some of the numerous bird remains found in this fauna have been made by Wetmore (1944), Tordoff (1951, 1959), and Collins (1964). Among the bird material yet to be described are 13 fossils which represent owls and which are the subject of this paper. The general paleoecology of the Rexroad fauna has been described by Hibbard (1941). The specimens herein described were collected at three localities: K.U. Locality no. 3, Fox Canyon Locality (UM-K1-47), and K.U. Locality 2a (Hibbard, 1950). The nomenclature of the bones used is that of Howard (1929), except where noted. Modern skeletons used for comparative material included representatives of all genera of owls occurring in the New World except Pseudoscops and Gymnoglaux and are mostly from the collections of The University of Michigan Museum of Zoology (UMMZ). Supplemental specimens were borrowed from the United States National Museum and the Museum of Vertebrate Zoology, Berkeley, California. The fossils are deposited in the collection of The University of Michigan Museum of Paleontology (UMMP).
A New Testudo from the Upper Pliocene of Kansas with Additional Notes on Associated Rexroad Mammals
From the beginning of his explorations of the Rexroad formation for vertebrate fossils, Dr. Claude W. Hibbard noted the presence of a very large tortoise in the fauna. For some years only fragments of the shell were found, chiefly from Rexroad localities (Nos, 2, 2a, 3, UM-K1-47), in Meade County (Hibbard 1950). In the summer of 1940 the plastron and fragments of the carapace of a large tortoise were collected by the field party of the University of Kansas Museum of Natural History at the type locality of the Rexroad formation south of locality No. 3. This specimen, No. 9399, remained unstudied at the University of Kansas Museum of Natural History until further material could be obtained.