Stratigraphy and Taphonomy of Grizzly Buttes, Bridger Formation, and the Middle Eocene of Wyoming

Alexander, John P.; Burger, Benjamin John

doi:10.1007/978-1-4615-1271-4_6

Cited by 21 publications

(17 citation statements)

References 23 publications

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“…These materials are the results of collecting efforts by J. Alexander from 1990–2000 in the Bridger Formation of Grizzly Buttes (Bridger B), Bridger Basin, Wyoming [42], [43]. Before further preparation, one partially prepared block of AMNH 143612 revealed what were clearly semi-articulated elements of an adapiform foot (Fig.…”

Section: Resultsmentioning

confidence: 99%

Evidence for a Grooming Claw in a North American Adapiform Primate: Implications for Anthropoid Origins

et al. 2012

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Among fossil primates, the Eocene adapiforms have been suggested as the closest relatives of living anthropoids (monkeys, apes, and humans). Central to this argument is the form of the second pedal digit. Extant strepsirrhines and tarsiers possess a grooming claw on this digit, while most anthropoids have a nail. While controversial, the possible presence of a nail in certain European adapiforms has been considered evidence for anthropoid affinities. Skeletons preserved well enough to test this idea have been lacking for North American adapiforms. Here, we document and quantitatively analyze, for the first time, a dentally associated skeleton of Notharctus tenebrosus from the early Eocene of Wyoming that preserves the complete bones of digit II in semi-articulation. Utilizing twelve shape variables, we compare the distal phalanges of Notharctus tenebrosus to those of extant primates that bear nails (n = 21), tegulae (n = 4), and grooming claws (n = 10), and those of non-primates that bear claws (n = 7). Quantitative analyses demonstrate that Notharctus tenebrosus possessed a grooming claw with a surprisingly well-developed apical tuft on its second pedal digit. The presence of a wide apical tuft on the pedal digit II of Notharctus tenebrosus may reflect intermediate morphology between a typical grooming claw and a nail, which is consistent with the recent hypothesis that loss of a grooming claw occurred in a clade containing adapiforms (e.g. Darwinius masillae) and anthropoids. However, a cladistic analysis including newly documented morphologies and thorough representation of characters acknowledged to have states constituting strepsirrhine, haplorhine, and anthropoid synapomorphies groups Notharctus tenebrosus and Darwinius masillae with extant strepsirrhines rather than haplorhines suggesting that the form of pedal digit II reflects substantial homoplasy during the course of early primate evolution.

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Section: Resultsmentioning

confidence: 99%

Evidence for a Grooming Claw in a North American Adapiform Primate: Implications for Anthropoid Origins

et al. 2012

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“…Mammalian fossils include apatotheres, artiodactyls, chiropterans, carnivores, condylarths, dermopterans, dinoceratans (uintatheres), edentates, insectivores, leptictids, marsupials, pantolestids, perissodactyls, primates, rodents, taeniodonts, and tillodonts unpublished paleontological data, University of Colorado Museum, compiled in 2002). Despite the relative ease with which diverse and statistically significant fossil samples can be collected, and the large historical collections of Bridger vertebrates available in many museums, taphonomic and paleoecologic studies of Bridger vertebrate faunas are relatively few (Alexander and Burger 2001;Brand et al 2000;Murphey et al 1999;Murphey and Townsend 2005;). …”

Section: Bridger Formationmentioning

confidence: 99%

Paleontological overview of oil shale and tar sands areas in Colorado, Utah, and Wyoming.

Murphey¹,

Daitch²

2009

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“…Type locality and horizon.`Forbidden City' locality, Grizzly Buttes area, Bridger Formation, Middle Eocene of Wyoming; Blacks Fork Member of the Bridger Formation (Wood 1934;Alexander and Burger 2001). This locality has also been referred to as The Woodburne Locality and East Grizzly Buttes (Alexander and Burger 2001;B.…”

Section: Derivation Of Name Latinisation Of the Locality Of Amnh 303mentioning

confidence: 99%

“…This locality has also been referred to as The Woodburne Locality and East Grizzly Buttes (Alexander and Burger 2001;B. J. Burger, pers.…”

Section: Derivation Of Name Latinisation Of the Locality Of Amnh 303mentioning

confidence: 99%

“…3A±F), specimen preserved in a number of slabs and consisting of ten fragmentary vertebrae, a portion of the synsacrum, a partial sternum, a fragmentary pelvis, the cranial end of the right coracoid, a fragment of the caudal end of the right coracoid, a cranial portion of the left coracoid, the cranial half of the right scapula (the caudal end embedded in matrix), the left scapula (missing only the caudal-most tip), the proximal end of a right humerus, medial fragment of the left humerus, right and left radius, right and left ulna, and 23 unidenti®able bone fragments. AMNH 30331 is preserved in a ®ne-grained, light grey sandstone.Type locality and horizon.`Forbidden City' locality, Grizzly Buttes area, Bridger Formation, Middle Eocene of Wyoming; Blacks Fork Member of the Bridger Formation (Wood 1934;Alexander and Burger 2001). This locality has also been referred to as The Woodburne Locality and East Grizzly Buttes (Alexander and Burger 2001; B. J. Burger, pers.…”

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A crown‐group galliform bird from the Middle Eocene Bridger Formation of Wyoming

Gulas-Wroblewski¹,

Wroblewski²

2003

Palaeontology

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ABSTRACT. Despite an extensive described fossil record of Galliformes (Aves:`landfowl'), very few specimens have been considered within a phylogenetic context. Here we present a cladistic analysis and description of a new, well-preserved and well-dated fossil specimen from the Middle Eocene Bridger Formation of Wyoming (c. 50 Ma). Amitabha urbsinterdictensis gen. et. sp. nov. is assigned to Galliformes on the basis of the presence of derived characters including double, and open, incisurae laterales on the sternum and an incisura capitis of the proximal humerus that is enclosed from the crus dorsale fossa by a distinct ridge. Amitabha is considered to be a member of the large and diverse`phasianoid' clade of Galliformes (including, for example, the pheasants, peafowl and turkeys) owing to a lack of extensive pneumaticity in the sternal plate. The age of this avian taxon and degree of preservation allow for a discussion of the use of fossil birds for the calibration of`molecular clock' hypotheses and dating divergences within Neornithes in general, and Galliformes in particular.KEY WORDS: Eocene,`landfowl', Galliformes, Wyoming, cladistics, phylogeny.T H E avian order Galliformes (`landfowl') includes such familiar taxa as junglefowl, peacocks and turkeys and generally has been considered to be one of the more basal clades of modern birds ( Neornithes sensu Cracraft 1988,`crown-clade' Aves of others; Gauthier 1986; Gauthier and de Queiroz 2001). Existing systematic treatments of these birds (e.g. Sibley and Monroe 1990;McGowan 1994) suggest that the order comprises at least ®ve distinct families, the Megapodiidae (megapodes and relatives), Numididae (guineafowl), Phasianidae (pheasants and relatives), Odontophoridae (New World quails), and Cracidae (curassows and relatives;Wetmore 1960;Cracraft 1981;Sibley and Ahlquist 1990). Recent cladistic analysis of over 100 morphological characters (Dyke and Gulas 2002;Dyke et al. 2003) found a basalmost, monophyletic Megapodiidae to be the sister-group to all other Galliformes, followed by Cracidae as the sister-group to the`phasianoids' (Text-®g. 1).Upon initial inspection, the described fossil record of this avian order appears extensive: reputed remains of galliform birds are described from deposits that range in age from the latest Cretaceous to the Recent (Brodkorb 1964;Unwin 1993; Hope in press). However, the fragmentary nature of supposed fossil galliform' records from the Cretaceous (Hope in press) as well as problems resulting from the polarization of the few phylogenetically informative characters preserved in these specimens (Clarke 1999) places the oldest certain record of the order (described to date) in the Lower Eocene Green River Formation of the United States (Grande 1984). This taxon, Gallinuloides wyomingensis Eastman, 1900, was placed within the family Gallinuloididae by Lucas (1900), now also considered to contain a number of somewhat younger and incompletely known specimens (Milne-Edwards 1867±71;Tordoff and Macdonald 1957;Crowe and Short 1992;. A num...

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Stratigraphy and Taphonomy of Grizzly Buttes, Bridger Formation, and the Middle Eocene of Wyoming

Cited by 21 publications

References 23 publications

Evidence for a Grooming Claw in a North American Adapiform Primate: Implications for Anthropoid Origins

Evidence for a Grooming Claw in a North American Adapiform Primate: Implications for Anthropoid Origins

Paleontological overview of oil shale and tar sands areas in Colorado, Utah, and Wyoming.

A crown‐group galliform bird from the Middle Eocene Bridger Formation of Wyoming

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