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 Ibises from the Rexroad Fauna of the Upper Pliocene of Kansas
T HE extensive fossil collections made by Claude W. Hibbard and his field assistants since 1936 from the Upper Pliocene deposits of Meade County, Kansas have made the Rexroad fauna, Rexroad Formation, Blancan age, perhaps the most completely known fauna from the High Plains. In this fossil material of both invertebrates and vertebrates there has been a wealth of bird material, some of which has been previously identified by Wetmore (1944) and Tordoff (1951, 1959). Among the elements described by Wetmore (lot. cit.) was part of a coracoid of a small ibis which could not be definitely identified. Miller and Bowman (1956) described an extinct species of small ibis, Plegadis gracilis, from deposits of slightly later age in Cita Canyon, Randall County, Texas. They felt that gracilis perhaps represented the same species previously encountered by Wetmore. Since that time additional ibis remains have been recovered from the Rexroad fauna and form the basis of this paper.
Die Populationsdynamik Von Canthocampt Us Staphylinus (Jurine) (Copepoda, Harpacticoida) Im Litoral Des Bodensees
The population dynamics of Canthocamptus staphylinus in the littoral zone of Lake Constance are described (fig. 2). Adult animals aestivate as cysts. The main part of the population emerges from the cysts in autumn. During the resting stage and the first spell after emerging, mortality is very low (fig. 3). Reproduction, expressed as numbers of ovigerous females, begins in November and reaches its maximum in January. The new generation becomes adult in May/June and encysts without previous reproduction. According to Sarvala (1979) it may be possible, that in littoral populations dormancy is induced by long day periods and temperatures of over 12° C (figs. 1, 2). In the profundal zone C. staphylinus also forms cysts, however, both light and temperature are not likely to induce this stage in depths of over 60 m.