Placerias (Reptilia, Dicynodontia) from the Upper Triassic of the Newark Supergroup, North Carolina, USA, and its biochronological significance

1998 ◽  
Vol 1998 (7) ◽  
pp. 432-448 ◽  
Author(s):  
Spencer G. Lucas
2012 ◽  
Vol 86 (2) ◽  
pp. 368-390 ◽  
Author(s):  
Andrew B. Heckert ◽  
Jonathan S. Mitchell ◽  
Vincent P. Schneider ◽  
Paul E. Olsen

The Moncure microvertebrate locality in the Cumnock Formation, Sanford sub-basin, North Carolina, dramatically increases the known Late Triassic age vertebrate assemblage from the Deep River Basin. The ∼50,000 recovered microvertebrate fossils include osteichthyans, amphibians, and numerous lepidosauromorph, archosauriform, and synapsid amniotes. Actinopterygian fossils consist of thousands of scales, teeth, skull, and lower jaw fragments, principally of redfieldiids and semionotids. Non-tetrapod sarcopterygians include the dipnoan Arganodus sp., the first record of lungfish in the Newark Supergroup. Temnospondyls are comparatively rare but the preserved centra, teeth, and skull fragments probably represent small (juvenile) metoposaurids. Two fragmentary teeth are assigned to the unusual reptile Colognathus obscurus (Case). Poorly preserved but intriguing records include acrodont and pleurodont jaw fragments tentatively assigned to lepidosaurs. Among the archosauriform teeth is a taxon distinct from R. callenderi that we assign to Revueltosaurus olseni new combination, a morphotype best assigned to cf. Galtonia, the first Newark Supergroup record of Crosbysaurus sp., and several other archosauriform tooth morphotypes, as well as grooved teeth assigned to the recently named species Uatchitodon schneideri. Synapsids represented by molariform teeth include both “traversodontids” assigned to aff. Boreogomphodon and the “dromatheriid” Microconodon. These records are biogeographically important, with many new records for the Cumnock Formation and/or the Newark Supergroup. In particular, Colognathus, Crosbysaurus, and Uatchitodon are known from basins of Adamanian age in the southwestern U.S.A. These new records include microvertebrate taxa more typical of non-Newark basins (abundant archosauriforms, temnospondyls, lungfish) as well as more typical Newark osteichthyans and synapsid-rich faunal elements.


1999 ◽  
Vol 19 (2) ◽  
pp. 351-354 ◽  
Author(s):  
Hans-Dieter Sues ◽  
Paul E. Olsen ◽  
Joseph G. Carter

2001 ◽  
Vol 88 (9) ◽  
pp. 1558-1567 ◽  
Author(s):  
Brian J. Axsmith ◽  
Michael Krings ◽  
Thomas N. Taylor

1986 ◽  
Vol 60 (5) ◽  
pp. 1086-1096 ◽  
Author(s):  
Pamela J. W. Gore ◽  
Alfred Traverse

Fossilized notostracan carapaces and abdominal fragments are present in the Upper Triassic (Rhaetian) Bull Run Formation in the Culpeper Basin near Manassas, Virginia. Over 250 notostracan carapaces and carapace fragments and three abdominal fragments with attached caudal rami were collected from light olive-gray, grayish-red, and brownish-gray shales in three on-strike localities. Carapace and abdomen are attached in one specimen. The Culpeper Basin notostracans have a rudimentary supra-anal plate and are identified as Triops cf. cancriformis. Their carapaces are indistinguishable from those of modern forms.Relatively few notostracan fossils are known and none have been reported previously from the Triassic of North America. Triassic notostracans, however, have been reported from Europe and Africa. Fossil notostracans have been reported from North America only once previously, from the Permian of Oklahoma.The notostracans are associated with conchostracans (Cyzicus sp.), ostracodes (Darwinula sp.), fish scales, insects, plant fragments, and stromatolites.The notostracan-bearing beds are present at the top of a transgressive-regressive sequence, indicating that the notostracans inhabited shallow water near the edge of a perennial lake. Palynology indicates that these beds are most likely mid- to late-Rhaetian in age.


2003 ◽  
Vol 23 (2) ◽  
pp. 329-343 ◽  
Author(s):  
Hans-Dieter Sues ◽  
Paul E. Olsen ◽  
Joseph G. Carter ◽  
Diane M. Scott

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