Browsing by Author "Van Valen, Leigh M."
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Item Deltatheridia, a new order of mammals. Bulletin of the AMNH ; v. 132, article 1(New York : [American Museum of Natural History], 1966) Van Valen, Leigh M."A reconsideration of the phylogeny of some early placental mammals, especially the creodonts, has resulted in the removal of all creodonts except the Miacidae from the Carnivora. The Arctocyonidae and their descendants, the Mesonychidae, are placed in the Condylarthra, and a new order, the Deltatheridia, is created for the Oxyaenoidea, the Palaeoryctidae, the Didymoconidae, and Micropternodus. The zalambdodont insectivores may or may not also be referable to the Deltatheridia. A survey of taxonomically significant characters indicates that the Miacidae are apparently closer to the Arctocyonidae than to the Pantolestinae or to the Deltatheridia. The whales were probably derived from mesonychids in the Paleocene. A detailed consideration of the morphology, systematics, and evolution of the Didelphodontinae is presented, and observations are made on many other mammalian genera, mainly, but not exclusively, of the Deltatheridia. Greatest emphasis is placed on the evolution of dental structure and occlusion, and cranial circulation. A detailed terminology is proposed for the structures of primitive therian teeth. Teeth of possible Tiffanian and Puercan oxyaenoid ancestors are described. Apterodon is tentatively referred to the Mesonychidae; Micropternodus, Nyssodon, and Sarcodon are referred to the Palaeoryctidae; Kochictis and Kopidodon, to the Mioclaeninae; Argillotherium is referred to the Oxyaeninae; and Praolestes, Opisthopsalis, Hyracolestes, and Xenacodon are referred to the Erinaceoidea. New genera are Avunculus in the Didelphodontinae, Pararyctes in the Palaeoryctinae, Mongoloryctes in the Didymoconidae, and Epapheliscus in the Apheliscinae. A new species of Palaeoryctes is described from the late Paleocene, one of Oxyaena, from the early Eocene; and one of Oxyaenodon, from the late Eocene. A possible case of geographic speciation in Didelphodus is presented, and comments are made on determining the relative adaptiveness of different characters, conditions of competitive exclusion, criteria of taxonomic definitions, and other theoretical matters"--P. 112.Item The first discovery of a Cretaceous mammal. American Museum novitates ; no. 2285(New York, N.Y. : American Museum of Natural History, 1967) Van Valen, Leigh M.; Wortman, Jacob Lawson.; Hill, R. S. (Russell S.)"The first discovery (recognition) of a Cretaceous mammal was that of Meniscoessus conquistus by Wortman in 1882. Its type locality can be restricted to part of Harding County, South Dakota, from newly uncovered correspondence. Mammals of the late Cretaceous Bug Creek facies occur in Wyoming as well as in eastern Montana, and were first collected in 1892"--P. [1].Item New Paleocene insectivores and insectivore classification. Bulletin of the AMNH ; v. 135, article 5(New York : [American Museum of Natural History], 1967) Van Valen, Leigh M."New genera and species are Pantinomia ambigua and Pantomimus leari, both possible pantolestids from the middle Paleocene; Leptonysson basiliscus, a middle Paleocene leptictid; and the apheliscines Parapheliscus bjorni and P. wapitiensis, the former from the late Paleocene and the latter from the early Eocene. Palaeosinopa senior is made the type of a new genus, Paleotomus, of the Palaeoryctidae, and the formerly referred specimens of this species are made a new species, Palaeosinopa simpsoni, of the Pantolestidae. These new taxa and other evidence indicate that the interrelationships of early Cenozoic insectivores are even more poorly understood than is commonly believed. The Pentacodontinae are removed from the Pantolestidae, provisionally as a separate family, and a number of generic synonymies and transfers of genera are made. These changes, together with a generic revision of the Leptictidae and other suggestions, do not greatly clarify which similarities among the families are convergent and which are indicative of relationship. A classification of the insectivores and deltatheridians is given that differs in a number of respects from the others available. New suprageneric taxa are the following: Erinaceota and Hyaenodonta, new suborders; Adapisoriculinae, Unuchiniinae Van Valen and McKenna, Thylacaelurinae, and Gypsonictopinae, new subfamilies; and Scaptonychini, new tribe. Primitive erinaceoids are more or less arbitrarily grouped into four subfamilies of the Adapisoricidae. The interrelations of moles are discussed. A family Plesiosoricidae is included in the Soricoidea. All zalambdodonts are tentatively removed from the Insectivora to the Deltatheridia, and recent work on the Hyaenodonta is critically reviewed. The Dermoptera and Macrocroscelidea are treated as suborders of the Insectivora"--P. 278.