Browsing by Author "Woodburne, Michael O."
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Item The first Tertiary monotreme from Australia. American Museum novitates ; no. 2588(New York, N.Y. : American Museum of Natural History, 1975) Woodburne, Michael O.; Tedford, Richard H."Remains of a new genus and species of fossil, ornithorhynchid monotreme are described. The specimens were recovered from Miocene deposits in South Australia and are part of the Ngapakaldi and equivalent aged faunas in this region. The fossil genus represents the oldest record of the group in Australia and begins to fill a large gap in our understanding of the evolution of the Monotremata"--P. [1].Item New early Eocene mammalian fauna from western Patagonia, Argentina. (American Museum novitates, no. 3638)(2009) Tejedor, Marcelo F.; Goin, Francisco.; Gelfo, Javier N.; López, Guillermo (Paleontologist); Bond, Mariano.; Carlini, Alfredo A.; Scillato-Yané, Gustavo J.; Woodburne, Michael O.; Chornogubsky, Laura.; Aragón, Eugenio.; Reguero, Marcelo.; Czaplewski, Nicholas J.; Vincon, Sergio.; Martin, Gabriel M.; Ciancio, Martín.Two new fossil mammal localities from the Paleogene of central-western Patagonia are preliminarily described as the basis for a new possible biochronological unit for the early Eocene of Patagonia, correlated as being between two conventional SALMAs, the Riochican (older) and the Vacan subage of the Casamayoran SALMA. The mammal-bearing strata belong to the Middle Chubut River Volcanic-Pyroclastic Complex (northwestern Chubut Province, Argentina), of Paleocene-Eocene age. This complex includes a variety of volcaniclastic, intrusive, pyroclastic, and extrusive rocks deposited after the K-T boundary. Geochronological data taken from nearby volcanic deposits that underlie and overlie the mammal-bearing levels indicate that both faunas are of late early Eocene age (Ypresian-Lutetian boundary). In addition to more than 50 species of mammals, including marsupials, ungulates, and xenarthrans, two lower molars are the oldest evidence of bats in South America. Paleobotanical and palynological evidence from inferred contemporary localities nearby indicate subtropical environments characterized by warm and probably moderately humid climate. Remarkably, this new fauna is tentatively correlated with Eocene mammals from the La Meseta Formation in the Antarctic Peninsula. We conclude that the two localities mentioned above are part of a possible new biochronological unit, but the formal proposal of a new SALMA awaits completion of taxonomic analysis of the materials reported upon here. If the La Meseta fauna is correlated biochronologically to western Patagonia, this also suggests a continental extension of the biogeographic Weddelian Province as far north as central-western Patagonia.Item Phyletic diversification of the Cormohipparion occidentale complex (Mammalia, Perissodactyla, Equidae), late Miocene, North America, and the origin of the Old World Hippotherium datum ; Bulletin of the American Museum of Natural History, no. 306(New York, NY : American Museum of Natural History, 2007) Woodburne, Michael O.Study of the materials in the American Museum of Natural History that pertain to the taxon Cormohipparion occidentale Skinner and MacFadden (1977) reveals that at least six species are represented. This is based on data from the cranium, upper dentition, lower dentition, and mandible. The taxa embrace a period of time from about 12.5 Ma to 10 Ma. Major sites or faunas include the Dove Spring Formation (medial Clarendonian, California; Burge Local Fauna (early Clarendonian, Nebraska); Minnechaduza Fauna, Nebraska; MacAdams Quarry, Texas (early medial Clarendonian); Gidley Horse Quarry (late medial Clarendonian, Texas); XMas-Kat, Hans Johnson, and Machaerodus quarries (late medial Clarendonian, Nebraska); and Ash Hollow Formation (late medial Clarendonian, South Dakota). The name Cormohipparion occidentale is restricted to the larger of two species that occur contemporaneously in medial Clarendonian sites in Nebraska and, alone, at the Ed Ross Ranch Quarry, South Dakota. The second species in the XMas-Kat and related quarries is assigned to Cormohipparion matthewi, n.sp. A taxon from the Burge Local Fauna is assigned to Cormohipparion merriami, n.sp. Another taxon from the Burge Local Fauna is assigned to Cormohipparion johnsoni, n.sp. Materials from the Texas sites are allocated as Cormohipparion fricki, n.sp., and Cormohipparion skinneri, n.sp., from the MacAdams Quarry and Gidley Horse Quarry, respectively. Cormohipparion fricki, n.sp., also is represented in the Minnechaduza Fauna, Nebraska. Cormohipparion is restricted geographically to North America. Based on this review, Cormohipparion johnsoni, n.sp., is the most plesiomorphic species of the C. occidentale group of taxa. Cormohipparion quinni is a plausible ancestor (sister-taxon) for the C. occidentale group, but also persisted with it until about 12 Ma. During their radiation, elements of the C. occidentale group demonstrate an increase in upper cheek tooth crown height and complexity of the enamel pattern, as well as an increase in overall cranial size, with each species showing its own mosaic of parameters. The interval of 12.5-10 m.y. witnessed the initiation of a period of climatic cooling and an eventual expansion of vegetation communities toward more open associations, in part showing an increase in grassy areas. Apparently, the C. occidentale group developed and maintained a mixed-feeding adaptation to these conditions, even though it had evolved very hypsodont cheek teeth by about 10 Ma (C. occidentale, s.s.; C. skinneri, n.sp.). Cormohipparion johnsoni, n.sp., and C. merriami, n.sp., are followed by C. fricki, n.sp., at about 12-11.5 Ma, which demonstrates an increased crown height and complexity of the upper cheek teeth along with the persistence of a functional dP1 into the adult condition. At least in C. fricki, n.sp., and likely also C. merriami, n.sp., the pre- and postfossettes of P2 commonly were confluent. All of these features are to be found in early Pannonian C members of Hippotherium of the Old World, and it is likely that a taxon such as C. fricki, n.sp., was associated with the Old World dispersal event that resulted in the presence of H. primigenium. A specimen of Cormohipparion sp. from deposits about 12 Ma old in California shows the proper morphology (enhanced by a significant increase in fossette complexity) to be a possible member of the dispersal population prior to its exit to the Old World at about 11 Ma. Subsequent North American species of the Cormohipparion occidentale group lived from about 11 Ma to 10 Ma and convergently approach (but do not equal) the enamel pattern complexity found in Hippotherium primigenium but surpass it in upper cheek tooth crown height, in the almost complete loss of dP1, and in a diminished frequency of confluence of the pre- and postfossetttes in P2. Two of these species, C. occidentale, s.s., and C. skinneri, n.sp., apparently populated a more northern (Great Plains) versus a southern (Texan) district, with C. occidentale, s.s., being sympatric with the (?secondarily) smaller C. matthewi, n.sp. The sample of C. occidentale, s.s., from the XMas-Kat quarries of Nebraska differs somewhat in a few cranial and dental parameters from samples from the Machaerodus and Hans Johnson quarries. Whereas the material from the XMas-Kat and Machaerodus quarries seems contemporaneous on geological grounds, the age of the sample from the Hans Johnson Quarry is not as securely dated. It is possible that the cranial differences (mainly the size of the preorbital fossa) and dental parameters (the persistence of a small and apparently functionally insignificant dP1 in adult female, but not male, crania) are variations in a contemporaneous but somewhat polymorphic population. Alternatively, it is possible that the Hans Johnson sample, at least, may be chronologically somewhat older than that from the Xmas-Kat quarries and that the morphological differences represent in part a more plesiomorphic condition for its specimens.Item Reappraisal of the Cormohipparion from the Valentine Formation, Nebraska. American Museum novitates ; no. 3163(New York, N.Y. : American Museum of Natural History, 1996) Woodburne, Michael O.Item Systematics, biogeography, and evolution of Cynorca and Dyseohyus (Tayassuidae). Bulletin of the AMNH ; v. 141, article 2(New York : [American Museum of Natural History], 1969) Woodburne, Michael O."The genus Cynorca Cope, 1867, is a small peccary of Miocene age which stands at the base of the second evolutionary radiation of the Tayassuidae. Although its ancestry has not been brought to light, the genus probably arose from Thinohyus or Perchoerus, primitive genera that range in age from early Oligocene to early Miocene. The oldest known species of Cynorca is C. sociale (Marsh, 1875), recorded from deposits of early Miocene age in Oregon, Texas, and possibly Nebraska. Cynorca sociale was probably adapted to a relatively moist, temperate climate. Three species of Cynorca are recognized as having been derived from C. sociale. Cynorca proterva Cope (1867), the genotypic species, is known from deposits of probably early late Miocene age in Maryland, South Carolina, Texas, and Nebraska. Although the evidence is imperfect, it is likely that C. proterva arose from a local, coastal population of C. sociale sometime in the early or middle Miocene. Inasmuch as C. proterva has been recorded from primarily Eastern and Gulf coastal localities, it almost certainly preferred moist, lowland habitats. This species apparently also ranged into areas such as western Nebraska along the courses of the major east-flowing tributaries of the proto-Mississippi River system. Cynorca occidentale, new species, is first found in middle Miocene deposits of the Montana-Wyoming-Nebraska area after having differentiated from a local population of C. sociale. Thereafter, in the late Miocene, C. occidentale was apparently restricted to areas of more xeric conditions in southern California. A third species, C. hesperia (Marsh, 1871), is of uncertain status. If a valid species, it lived in Oregon in late middle Miocene or early late Miocene time and was probably derived from a northwestern population of C. sociale. Dyseohyus Stock, 1937, is a larger and more advanced derivative of Cynorca. The more primitive of the two species, D. fricki Stock, 1937, is restricted to the late Miocene of California. Dyseohyus fricki is found in some of the same deposits as C. occidentale and probably was also adapted to relatively xeric conditions. Dyseohyus fricki may have been derived from a segment of the Oregon population of C. sociale that was invading drier habitats. The more advanced species of Dyseohyus, D. stirtoni, new species, is found in deposits of late Miocene age in Colorado, Nebraska, and Texas. Dyseohyus stirtoni was apparently adapted to somewhat drier conditions than the geologically and geographically proximal species, C. proterva. Specimens known as Dyseohyus or Cynorca from Texas range in age from early to late Miocene. If this group of specimens represents a single species, it may have given rise to D. stirtoni and was, in turn, derived from C. sociale. Inasmuch as both D. fricki and D. stirtoni were probably derived from the same species of Cynorca (C. sociale), they can be considered as pertaining to one genus. Dyseohyus, as currently constituted, might be polyphyletic at the subspecies level, but the evidence is not adequate for a definitive decision. Aside from C. sociale, which was ancestral to Dyseohyus, and D. stirtomi, which probably gave rise to some of the later peccary species such as Prosthennops niobrarensis, all other species of the two genera reviewed in this report are terminal lineages. A large form, ?Dyseohyus sp., from the late Miocene of Colorado and early Pliocene of Nevada, is aberrant and of uncertain ancestry. As far as can be determined, it, too, represents a terminal lineage"--P. 351.Item Vertebrate fossils and their context : contributions in honor of Richard H. Tedford. Bulletin of the AMNH ; no. 279(New York, NY : American Museum of Natural History, 2003) Flynn, Lawrence J. (Lawrence John), 1932-; Tedford, Richard H.; Novacek, Michael J.; Woodburne, Michael O.; Hunt, Robert M., Jr., 1941-; Gould, Gina C.; Gaffney, Eugene S.; Qiu, Zhanxiang.; Demere, Thomas A.; Berta, Annalisa.; Adam, Peter J.; Wang, Banyue.; Baskin, Jon A.; Van Valkenburgh, Blaire.; Sacco, Tyson.; Wang, Xiaoming, 1957-; Stevens, Margaret Skeels.; Stevens, James Bowie.; Lindsay, Everett H.; Whistler, David P.; Lander, E. Bruce.; Morgan, Gary S.; Lucas, Spencer G.; Ferrusquia-Villafranca, Ismael.; Webb, S. David (Sawney David), 1936-; Beatty, Brian Lee.; Poinar, George.; MacFadden, Bruce J.; Repenning, Charles A.; Turnbull, William D.; Lundelius, Ernest L.; Archer, Michael, 1945-; Pledge, Neville S.; Rich, Thomas H. V.; Darragh, Thomas A.; Rich, Pat Vickers.; Ye, Jie.; Meng, Jin (Paleontologist); Wu, Wenyu.; Qiu, Zhuding.; Li, Chuan-Kuei.; Winkler, Alisa J.; Downs, Will.; Holec, Peter.; Emry, Robert J.; McKenna, Malcolm C.; Lofgren, Donald L.; Tong, Haiyan.