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Enrichment and stability in the Pliocene mammalian fauna of North China
- Lawrence J. Flynn, Richard H. Tedford, Qiu Zhanxiang
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- Journal:
- Paleobiology / Volume 17 / Issue 3 / Summer 1991
- Published online by Cambridge University Press:
- 14 July 2015, pp. 246-265
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The Late Neogene vertebrate fossil record from Yushe Basin presents multiple, superposed assemblages from a single area, spanning roughly the interval of 6–2 Ma. Both large and small mammals show peak species richness in the middle Pliocene but indicate relative faunal stability throughout the Pliocene. Large mammals show turnover, especially extinction, around 5 and 2.5 Ma. Small mammals indicate change (over half of the species and several genera), as well as turnover at the species level, between 4 and 3.4 Ma. The loosely controlled dating of these events does not disprove hypothetical correlation with events in North America and with global climatic shifts. Elements that lack Yushe antecedents, some being long-distance dispersers, appear throughout the section, but with little effect on the resident assemblage. First records of well-documented immigrants (from North America, Europe, Africa, southern Asia, or high latitudes) generally do not coincide with ecomorph extinctions. Early Pliocene exchange between Asia and North America appears to have been balanced in both directions and involved a small proportion of the fauna. Immigration probably was opportunistic and contributed to faunal enrichment. We interpret the Yushe Pliocene mammalian assemblages as representing a fauna that was stable from ca. 5 to 2.5 Ma and changed mainly by additions and congeneric species substitutions.
24 - Small Arctoid and Feliform Camivorans
- Edited by Donald R. Prothero, Occidental College, Los Angeles, Robert J. Emry, Smithsonian Institution, Washington DC
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- Book:
- The Terrestrial Eocene-Oligocene Transition in North America
- Published online:
- 06 July 2010
- Print publication:
- 13 June 1996, pp 486-497
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Summary
ABSTRACT
The Subparictidae (new family) are an endemic North American radiation of Chadronian (Subparictis) to Arikareean ursoids. The Amphicynodontinae are the earliest known members of the Family Ursidae and first occur in the latest Eocene (middle and late Chadronian) of North America, where they are represented by the middle Chadronian Campylocynodon personi and the late Chadronian? Amphicynodon major. Drassonax harpagops is an Orellan member of this subfamily. The Musteloidea (Mustelavus priscus) and the feliform carnivoran Palaeogale also have their earliest records in North America.
INTRODUCTION
This chapter examines a variety of rare, small, mainly Chadronian and Orellan carnivorans, which occur in rocks of the White River Group or equivalents in North and South Dakota, Wyoming, Nebraska, Colorado, Montana, and Saskatchewan. These include the genera Subparictis, Campy locynodon, Drassonax,? Amphicynodon, Mustelavus, and Palaeogale. The first four are assigned to the Ursoidea, the superfamily containing the extant Ursidae and Pinnipedia. Subparictis is a member of the Subparictidae, a new family which also includes Nothocyon and probably Parictis. Campylocynodon, Drassonax, and? Amphicynodon major are amphicyno-dontines, a subfamily that is much better represented in the Oligocene of Eurasia (Teilhard, 1915; Cirot and de Bonis, 1992). Mustelavus is a very primitive North American member of the Musteloidea, the superfamily which includes the Procyonidae and Mustelidae. The affinities of Palaeogale have not been resolved, but it is probably a primitive feliform. Amphicynodontines, musteloids, and Palaeogale all have a Holarctic distribution in the Oligocene, but their earliest records are in the late Eocene of North America.
15 - The Whitneyan-Arikareean transition in the High Plains
- Edited by Donald R. Prothero, Occidental College, Los Angeles, Robert J. Emry, Smithsonian Institution, Washington DC
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- Book:
- The Terrestrial Eocene-Oligocene Transition in North America
- Published online:
- 06 July 2010
- Print publication:
- 13 June 1996, pp 312-334
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Summary
ABSTRACT
We bring together lithostratigraphic, biostratigraphic, and magnetostratigraphic data from Nebraska and South Dakota to detail faunal change between 28-30 Ma in medial Oligocene time. This span records the transition from the White River chronofauna to the new assemblages that characterize the younger part of the Arikareean “age.” Although a regional disconformity of approximately a half-million year duration breaks the biostratigraphic sequence, the fossil record is reasonably continuous and mostly confined to the eolian facies. Between 28-30 Ma the White River chronofauna experienced significant enrichment in autochthonous clades especially hesperocyonine canids, oreodonts, camels, hypertragulids, and burrowing castoid and geomyoid rodents. Few allochthonous taxa are encountered so that the chronofauna was enriched without marked immigration or extinction. At approximately 28 Ma most of the White River genera leave the record, thus terminating the chronofauna. The fauna that emerges contains representatives of autochthonous lineages, some of which appeared during the enrichment phase of the White River chronofauna. In addition there are allochthonous genera that represent taxa new to midcontinental North America. The better resolved and calibrated fossil record allows re-examination of the definition and characterization of the beginning of the Arikareean mammal “age.” We propose that the initiation of the Arikareean Mammal “age” is signaled by the first appearance of taxa that enrich the White River chronofauna in latest Chron C11r and earliest Chron C11n (about 30 Ma).
21 - Canidae
- Edited by Donald R. Prothero, Occidental College, Los Angeles, Robert J. Emry, Smithsonian Institution, Washington DC
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- Book:
- The Terrestrial Eocene-Oligocene Transition in North America
- Published online:
- 06 July 2010
- Print publication:
- 13 June 1996, pp 433-452
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Summary
ABSTRACT
The White River Group of the late Eocene and Oligocene age contains some of the earliest and most primitive canids in North America. These archaic canids, mainly Hesperocyon and its close relatives, gave rise to several clades that contain ancestral forms for all three subfamilies of the Canidae: the paraphyletic Hesperocyoninae which became the dominate canids during the Arikareean, the monophyletic Borophaginae which flourished during the Miocene, and the monophyletic Caninae which did not diversify until Pliocene through Recent time. The middlelate Eocene (Duchesnean to Chadronian) saw the emergence of the first canids with a fully ossified entotympanic bulla and canid dentition (3 1 4 2/3 1 4 3), as represented by Prohesperocyon wilsoni and H. gregarius, which probably evolved from primitive cynoids such as Procynodictis. The White River canids began an initial diversification in the beginning of Oligocene (Orellan), giving rise to the earliest members of the borophagine (Cormocyon) and canine (Leptocyon) clades. At least six species can be recognized at this time: H. gregarius, “H.” coloradensis, “Mesocyon” temnodon, Osbornodon renjiei, Cormocyon pavidus, and Leptocyon sp. In Whitneyan time, the majority of the hesperocyonine clades began to be readily distinguishable, and the borophagines began to develop small, hypocarnivorous taxa. The number of species in the Whitneyan had increased to nine: H. gregarius, Paraenhydrocyon josephi, “M.” temnodon, Cynodesmus thooides, Osbornodon renjiei, O. Sesnoni, Ectopocynus antiquus, Cormocyon pavidus, and Oxetocyon cuspidatus.