Claude W. Hibbard

The Origin of the P3 Pattern of Sylvilagus, Caprolagus, Oryctolagus and Lepus

An Upper Pliocene population of Nekrolagus progressus (Hibbard) represented by 178 P3s from the Rexroad fauna has 11.8% of the individuals with a P3 enamel pattern that is like the Ps pattern of Sylvilagus, Caprolagus, Oryctolagus and Lepus . For the first time in the fossil record there is evidence for the time and place of the variation (mutation) within a population that produced a character of generic grade. It is proposed that this pattern developed in North America and gave rise to that now found in Sylvilagus, Caprolagus, Oryctolagus and Lepus . Cenozoic faunas of Eurasia that contain remains of Oryctolagus and Lepus are younger than the Rexroad fauna. Over 2,000 Recent Lepus, Oryctolagus and Sylvilagus dentitions were examined. Twelve Recent specimens of these three genera were found that contained the Nekrolagus pattern. The genera are quite recent in origin. These rabbits provide an excellent group for comparative study with the late Pliocene Nekrolagus to establish the rate of generic development. A phylogenetic summary is given to show the relationship of the Leporinae as based upon the development of P2 and P3.

New Mammals from the Rexroad Fauna, Upper Pliocene of Kansas

I am greatly indebted to Dr. Lee R. Dice and Dr. W. H. Burt of the University of Michigan; and Dr. H. H. Lane of the University of Kansas, for advice and criticism during the preparation of this paper. Acknowledgment is also made of the courtesy extended by C. D. Bunker of the University of Kansas; C. W. Gilmore, Dr. C. Lewis Gazin, G. S. Miller, Jr., and Dr. Remington Kellogg of the United States National Museum; A. H. Howell, and Dr. H. H. T. Jackson of the United States Biological Survey; E. Furlong of the California Institute of Technology; Dr. R. A. Stirton of the University of California; and Colin C. Sanborn of Field Museum of Natural History for permitting the study of the collections under their care or for the loan of comparative material and for advice. The drawings, unless otherwise credited, were made by Miss Frances Watson.

Stratigraphy and vertebrate paleontology of Pleistocene deposits of southwestern Kansas

The stratigraphy and vertebrate fossils of the Meade and Kingsdown silt formations of southwestern Kansas are discussed. Correlations are made with other deposits in Kansas and Oklahoma. Four local faunas are recognized in the Meade formation. The Cudahy, Tobin, and Wilson Valley faunas are considered as contemporaneous and occur in the Meade formation just below the Pearlette ash member. The Cudahy fauna, a glacial assemblage of invertebrates and vertebrates, is reported for the first time. The mammals recovered consist of 12 genera and 11 species. One genus and 8 species are described as new. The Kingsdown silt formation is divided into the lower and upper Kingsdown on the basis of lithology and associated vertebrate fossils. The characters of the deposits and the mammalian fossils taken from them are discussed.

UPPER PLIOCENE VERTEBRATES FROM KEEFE CANYON, MEADE COUNTY, KANSAS

A late Pliocene artesian spring basin in Meade County, Kansas, was a trap for animals that came to the spring for water. They were either trapped by quicksand or became mired in the bog area around the edge of the spring. Some of the larger mammals that inhabited the region at the time the Rexroad fauna lived were recovered from this deposit. The following forms new to the Rexroad fauna were recovered from the Keefe Canyon deposit: ?Megalonyx sp.; Dipoides rexroadensis sp. nov.; Martes foxi sp. nov.; Platygonus bicalcaratus Cope; Gigantocamelus spatulus (Cope); Pliauchenia cochrani sp. nov.; and Tanupolama blancoensis Meade.

An Upper Pliocene Fauna from Meade County, Kansas

A large vertebrate fauna from the Upper Pliocene of Kansas showing evidence of members of a boreal fauna associated with that of a more southern fauna. Indicating the climatic change which appeared in advance of the Pleistocene glaciation. Five classes of vertebrates are represented in the fauna. The paper treats only the Mammalia, which is represented by 7 orders, 14 families, 23 genera and 10 species of which the following are described as new: Sorex taylori sp. nov.; Eocastoroides lanei gen. et sp. nov.; Peromyscus eliasi sp. nov.; Sigmodon intermedius sp. nov.; Pliolemmus antiquus gen. et sp. nov.; Pliophenacomys subgen. nov.; Phenacomys primaevus sp. nov.; Kansasomys meadensis gen. et sp. nov.; Neondatra kansasensis gen. et sp. nov. With text figures.

Mammals of the Rexroad Fauna from the Upper Pliocene of Southwestern Kansas

INTRODUCTION The intensive collecting in the Upper Pliocene deposits in the summers of 1936 to 1940 inclusive by the Museums field party in Meade county, Kansas, has yielded one of the largest known mammalian faunas of Upper Pliocene age. The mammals show a close relationship with those from the Benson fauna of Arizona. The Rexroad fauna is considered to be approximately the same age as the Blanco, Benson and Hagerman faunas. I am greatly indebted to the members of our parties, especially Messers Harry Jacob, Ralph Taylor, George Rinker and Joe Tihen, who was in charge of the field party in the summer of 1940, for the careful work and untiring interest shown in collecting the small forms.

Two New Genera of Felidae from the Middle Pliocene of Kansas

Kansas has been noted for its rich fossil deposits for many years, though only within the past ten years has attention been paid to the Pliocene deposits, with the exception of the once famous Long Island quarry. During the past forty years a few scattered bones of Pliocene age have made their way into the Museum of Vertebrate Paleontology, some of which were picked up by our own expeditions. In the summer of 1924, Mr. H. T. Martin opened the first Pliocene quarry (known as the Edson Beds-North Quarry) with the purpose of collecting a Pliocene fauna for the Museum. He returned to this quarry in 1926, and also located and opened other quarries of this age. The summers of 1928, 1930 and 1931 were spent in collecting from Pliocene deposits of western Kansas.

Second Contribution to the Rexroad Fauna

A student of stratigraphy or paleontology who is unfamiliar with the Pliocene and Pleistocene deposits in southwestern Kansas, and with the exposures and fossil localities in this region is lost in trying to follow the recent literature pertaining to these deposits and their faunas. Many recent published papers have introduced new stratigraphic and faunal terms with no attempt to correlate these terms with previous work (see Fig. 1).

Four New Rabbits from the Upper Pliocene of Kansas

During the summer of 1937, the Kansas University Museum of Vertebrate Paleontology continued its Field Work on the Upper Pliocene Fauna of Kansas. With the cooperation of Messrs. Joe Tihen, Harry Jacob, Ben Bagrowski, Fred Holden, and Vernon Carter, students of the University, a large collection of vertebrates was obtained from the Upper Pliocene. Four apparently new rabbits were collected, which are described in the following paper. Since the work has not been completed in this area, the discussion of the fauna as a unit and its relationship to other faunas will appear at a later date.

Two New Cenozoic Microtine Rodents

Further washing of matrix from the Saw Rock Canyon local fauna locality in southwestern Kansas has produced numerous parts of a vole previously reported as Cosomys . Sufficient material has been found to show that the vole is distinct from Cosomys . It is here reported as a new species of the Pliocene genus Ogmodontomys . A lower jaw of a small vole from the early Pleistocene Sand Draw local fauna of Nebraska is described as a new genus and species. Cosomys primus Wilson, Hibbard, 1949. Contrib. Mus. Paleo., Univ. Mich., vol. 7, no. 5, p. 103, fig. 2C–E. Fig. 1 (A-F) Ogmodontomys sawrockensis sp. nov. (A and B) Occlusal view of RM1-M3, and lateral view of right ramus, paratype UMMP No. 29715