Basal ornithopod (Dinosauria: Ornithischia) teeth from the Prince Creek Formation (early Maastrichtian) of Alaska

2011 ◽  
Vol 48 (9) ◽  
pp. 1342-1354 ◽  
Author(s):  
Caleb Marshall Brown ◽  
Patrick Druckenmiller
Keyword(s):  
Upper Cretaceous ◽  
Cheek Tooth ◽  
North Slope ◽  
Sister Taxon ◽  
Hell Creek Formation ◽  
New Material ◽  
Previous Assignment ◽  
Stratigraphic Range

A diverse and prolific record of polar dinosaurs comes from the Upper Cretaceous (Campanian–Maastrichtian) sediments of the Prince Creek Formation exposed on Alaska’s North Slope. Previous assignment of basal ornithopod material from this formation has been based solely on teeth, which have either been referred to “hypsilophodontid” indet. or Thescelosaurus sp. Here, we re-examine this material and describe several new specimens, including five isolated premaxillary teeth and three cheek teeth. The premaxillary teeth are most similar to those of Thescelosaurus , whereas the cheek teeth are more similar to its sister taxon Parksosaurus , for which premaxillary teeth are unknown. Referral of this new material to Thescelosaurus would represent the oldest occurrence of this taxon and considerably extend its stratigraphic range. A more likely possibility is that the premaxillary teeth are referable to Parksosaurus, an interpretation that is more parsimonious from a stratigraphic perspective. Intriguingly, one cheek tooth previously referred to as “hypsilophodontid” cannot be referred to either Thescelosaurus or Parksosaurus. Previously, faunal comparisons of the Prince Creek Formation have largely been made with non-contemporaneous formations, including the Campanian-aged Judith River and Aguja formations, or to the latest Maastrichtian Hell Creek Formation. On the basis of age and faunal similarities, a more appropriate comparison should be made with coeval rocks of the Horseshoe Canyon. This study expands our knowledge of Cretaceous ornithischian diversity at polar paleolatitudes and underscores the importance of small, rare, or easily misidentified fossils in paleoecological studies.

NEW MATERIAL OF SMALL DINOSAURS FROM THE UPPER CRETACEOUS ALLISON MEMBER, MENEFEE FORMATION, NEW MEXICO

2019 ◽  
Author(s):  
Kara A. Kelley ◽  
◽  
Charlotte J.H. Hohman ◽  
Andrew T. McDonald ◽  
Douglas G. Wolfe
Keyword(s):  
New Mexico ◽  
Upper Cretaceous ◽  
New Material

New and little-known bryozoans from Monte León Formation (early Miocene, Argentina) and their paleobiogeographic relationships

2015 ◽  
Vol 89 (6) ◽  
pp. 956-965 ◽  
Author(s):  
Leandro M. Pérez ◽  
Juan López-Gappa ◽  
Miguel Griffin
Keyword(s):  
New Species ◽  
New Zealand ◽  
Close Relationships ◽  
Early Miocene ◽  
South American ◽  
The South ◽  
New Material ◽  
Recent Species ◽  
Stratigraphic Range

AbstractThe bryozoan fauna from the South American Cenozoic is poorly known. The study of new material collected in the Monte León Formation (early Miocene), gave us the opportunity to describe four new species: Valdemunitella canui n. sp., Foveolaria praecursor n. sp., Neothoa reptans n. sp., and Calyptotheca santacruzana n. sp. Two of them (V. canui and C. santacruzana) were first recorded by F. Canu and interpreted as recent species from the Australian bryozoan fauna, but are herein described as new species. The stratigraphic range of Otionella parvula (Canu, 1904) is extended to the early Miocene. The present study emphasizes the close relationships between the South American Neogene bryozoan faunas and those of other Gondwanan sub-continents such as New Zealand and Australia.

Revision of the status of Saurolophus (Hadrosauridae) from California, USA

2010 ◽  
Vol 47 (11) ◽  
pp. 1417-1426 ◽  
Author(s):  
Phil R. Bell ◽  
David C. Evans
Keyword(s):  
Phylogenetic Analysis ◽  
Sierra Nevada ◽  
Sister Taxon ◽  
Morphological Evidence ◽  
Magmatic Arc ◽  
The Status ◽  
Previous Assignment ◽  
Geographic Setting

The occurrence of Saurolophus from the Moreno Formation (late Maastrichtian) of California is investigated and an incomplete, poorly preserved, skull (LACM/CIT 2852) is described. The skull lacks the braincase (including the frontals) and much of the nasals, and the preserved portions are crushed or plastically deformed, which makes anatomical interpretations difficult. A preserved midline fragment of the conjoined nasals suggests that it lacked a gryposaur-like “Roman nose”, but the nature of the crest, if present, is impossible to determine with certainty. A phylogenetic analysis places this specimen as either the sister taxon of Saurolophus or as the sister taxon to a clade comprising Edmontosaurus and Anatotitan . There is no compelling morphological evidence to support the previous assignment of LACM/CIT 2852 to Saurolophus rather than to Edmontosaurus, and its poor preservation prevents positive assignment to any taxon below Hadrosaurinae indet. Given its geographic setting and morphological uncertainties, it is also possible that this specimen represents a separate taxon, but more material is needed to clarify the identity of the Moreno hadrosaurine. LACM/CIT 2852 does, however, provide evidence that Maastrichtian hadrosaurines ranged west of the Sierra Nevada magmatic arc, in an area where dinosaur diversity is poorly known.

Decapod crustaceans from the Semilla Sandstone Member, Mancos Shale (Upper Cretaceous), north-central New Mexico

1996 ◽  
Vol 70 (1) ◽  
pp. 111-116 ◽  
Author(s):  
Elizabeth K. Toolson ◽  
Barry S. Kues
Keyword(s):  
New Mexico ◽  
Upper Cretaceous ◽  
Decapod Crustaceans ◽  
North Central ◽  
Mancos Shale ◽  
First Time ◽  
Stratigraphic Range

The decapods Linuparus grimmeri Stenzel, Protocallianassa mortoni (Pilsbry) and Necrocarcinus (Cenomanocarcinus) vanstraeleni (Stenzel)? are described from the middle Turonian Semilla Sandstone Member, Mancos Shale, of north-central New Mexico. The main specimen of P. mortoni is unusually complete, consisting of a complete left first cheliped, parts of other pereiopods, and most of the abdomen. Both L. grimmeri and P. mortoni are reported for the first time from the southern Western Interior. The stratigraphic range of L. grimmeri is extended upward from the upper Cenomanian, and the range of P. mortoni downward from the Campanian.

scholarly journals A new dromaeosaurid (Dinosauria: Theropoda) from the Upper Cretaceous Wulansuhai Formation of Inner Mongolia, China

Zootaxa ◽  
2010 ◽  
Vol 2403 (1) ◽  
pp. 1 ◽  
Author(s):  
XING XU ◽  
JONAH N. CHOINIERE ◽  
MICHAEL PITTMAN ◽  
QINGWEI TAN ◽  
DONG XIAO ◽  
...  
Keyword(s):  
Late Cretaceous ◽  
Inner Mongolia ◽  
Upper Cretaceous ◽  
Systematic Position ◽  
Sister Taxon ◽  
New Taxon ◽  
Salient Features

We describe a new dromaeosaurid theropod from the Upper Cretaceous Wulansuhai Formation of Bayan Mandahu, Inner Mongolia. The new taxon, Linheraptor exquisitus gen. et sp. nov., is based on an exceptionally well-preserved, nearly complete skeleton. This specimen represents the fifth dromaeosaurid taxon recovered from the Upper Cretaceous Djadokhta Formation and its laterally equivalent strata, which include the Wulansuhai Formation, and adds to the known diversity of Late Cretaceous dromaeosaurids. Linheraptor exquisitus closely resembles the recently reported Tsaagan mangas. Uniquely among dromaeosaurids, the two taxa share a large, anteriorly located maxillary fenestra and a contact between the jugal and the squamosal that excludes the postorbital from the infratemporal fenestra. These features suggest a sister-taxon relationship between L. exquisitus and T. mangas, which indicates the presence of a unique dromaeosaurid lineage in the Late Cretaceous of Asia. A number of cranial and dental features seen in L. exquisitus and T. mangas, and particularly some postcranial features of L. exquisitus, suggest that these two taxa are probably intermediate in systematic position between known basal and derived dromaeosaurids. The discovery of Linheraptor exquisitus is thus important for understanding the evolution of some salient features seen in the derived dromaeosaurids.

Sign in / Sign up

Export Citation Format

Share Document