scholarly journals A Tyrannosauroid Metatarsus from the Merchantville Formation of New Jersey increases the diversity of non-Tyrannosaurid Tyrannosauroids on Appalachia

Author(s):  
Chase D Brownstein

For almost the entirely of the latter half of the Cretaceous, the continent of North America was divided into two sections, Laramidia in the west and Appalachia in the east. Unfortunately, this latter landmass recorded only a sparse fossil record of dinosaurs, obscuring those forms which must have occupied the eastern portion of North America during this time. Appalachian dinosaur faunas, though obscure, do seem to be different in composition from Laramidian ones. One particular element of Appalachian faunas that has attracted significant attention are the non-tyrannosaurid tyrannosauroids of the continent. Tyrannosauroids on Appalachia, though represented by at least two taxa (Appalachiosaurus montgomeriensis and Dryptosaurus aquilunguis), as well as many partial and fragmentary skeletons and elements, are nevertheless poorly know when compared to their western contemporaries. Here, one specimen, the partial metatarsus of a tyrannosauroid from the Campanian Merchantville Formation of New Jersey, is described in detail. The specimen may be differentiated from Appalachiosaurus montgomeriensis, Dryptosaurus aquilunguis, and an unnamed specimen from the Maastrichtian of New Jersey by several notable morphological features outside the spectrum of individual variation, as well as by factoring in biogeographical considerations. The new specimen thus has significance for representing a new morphotype of tyrannosauroid from Appalachia, suggesting greater diversity of the clade on the landmass. Because of this, tyrannosaur diversity in the Campanian of Appalachia was compared to the diversity of tyrannosaurs in Laramidia during the same period to analyze the similarities and differences between the biogeography of tyrannosaurs on each landmass. The results suggest that Appalachian non-tyrannosaurid tyrannosauroids experienced a similar amount of diversity to tyrannosaurids in Laramidia during the Campanian.

2017 ◽  
Author(s):  
Chase D Brownstein

For almost the entirely of the latter half of the Cretaceous, the continent of North America was divided into two sections, Laramidia in the west and Appalachia in the east. Unfortunately, this latter landmass recorded only a sparse fossil record of dinosaurs, obscuring those forms which must have occupied the eastern portion of North America during this time. Appalachian dinosaur faunas, though obscure, do seem to be different in composition from Laramidian ones. One particular element of Appalachian faunas that has attracted significant attention are the non-tyrannosaurid tyrannosauroids of the continent. Tyrannosauroids on Appalachia, though represented by at least two taxa (Appalachiosaurus montgomeriensis and Dryptosaurus aquilunguis), as well as many partial and fragmentary skeletons and elements, are nevertheless poorly know when compared to their western contemporaries. Here, one specimen, the partial metatarsus of a tyrannosauroid from the Campanian Merchantville Formation of New Jersey, is described in detail. The specimen may be differentiated from Appalachiosaurus montgomeriensis, Dryptosaurus aquilunguis, and an unnamed specimen from the Maastrichtian of New Jersey by several notable morphological features outside the spectrum of individual variation, as well as by factoring in biogeographical considerations. The new specimen thus has significance for representing a new morphotype of tyrannosauroid from Appalachia, suggesting greater diversity of the clade on the landmass. Because of this, tyrannosaur diversity in the Campanian of Appalachia was compared to the diversity of tyrannosaurs in Laramidia during the same period to analyze the similarities and differences between the biogeography of tyrannosaurs on each landmass. The results suggest that Appalachian non-tyrannosaurid tyrannosauroids experienced a similar amount of diversity to tyrannosaurids in Laramidia during the Campanian.


2017 ◽  
Author(s):  
Chase D Brownstein

For almost the entirely of the latter half of the Cretaceous, the continent of North America was divided into two sections, Laramidia in the west and Appalachia in the east. Unfortunately, this latter landmass recorded only a sparse fossil record of dinosaurs, obscuring those forms which must have occupied the eastern portion of North America during this time. Appalachian dinosaur faunas, though obscure, do seem to be different in composition from Laramidian ones. One particular element of Appalachian faunas that has attracted significant attention are the non-tyrannosaurid tyrannosauroids of the continent. Tyrannosauroids on Appalachia, though represented by at least two taxa (Appalachiosaurus montgomeriensis and Dryptosaurus aquilunguis), as well as many partial and fragmentary skeletons and elements, are nevertheless poorly know when compared to their western contemporaries. Here, one specimen, the partial metatarsus of a tyrannosauroid from the Campanian Merchantville Formation of New Jersey, is described in detail. The specimen may be differentiated from Appalachiosaurus montgomeriensis, Dryptosaurus aquilunguis, and an unnamed specimen from the Maastrichtian of New Jersey by several notable morphological features outside the spectrum of individual variation, as well as by factoring in biogeographical considerations. The new specimen thus has significance for representing a new morphotype of tyrannosauroid from Appalachia, suggesting greater diversity of the clade on the landmass. Because of this, tyrannosaur diversity in the Campanian of Appalachia was compared to the diversity of tyrannosaurs in Laramidia during the same period to analyze the similarities and differences between the biogeography of tyrannosaurs on each landmass. The results suggest that Appalachian non-tyrannosaurid tyrannosauroids experienced a similar amount of diversity to tyrannosaurids in Laramidia during the Campanian.


2017 ◽  
Author(s):  
Chase D Brownstein

For almost the entirely of the latter half of the Cretaceous, the continent of North America was divided into two sections, Laramidia in the west and Appalachia in the east. Unfortunately, this latter landmass recorded only a sparse fossil record of dinosaurs, obscuring those forms which must have occupied the eastern portion of North America during this time. Appalachian dinosaur faunas, though obscure, do seem to be different in composition from Laramidian ones. One particular element of Appalachian faunas that has attracted significant attention are the non-tyrannosaurid tyrannosauroids of the continent. Tyrannosauroids on Appalachia, though represented by at least two taxa (Appalachiosaurus montgomeriensis and Dryptosaurus aquilunguis), as well as many partial and fragmentary skeletons and elements, are nevertheless poorly know when compared to their western contemporaries. Here, one specimen, the partial metatarsus of a tyrannosauroid from the Campanian Merchantville Formation of New Jersey, is described in detail. The specimen may be differentiated from Appalachiosaurus montgomeriensis, Dryptosaurus aquilunguis, and an unnamed specimen from the Maastrichtian of New Jersey by several notable morphological features outside the spectrum of individual variation, as well as by factoring in biogeographical considerations. The new specimen thus has significance for representing a new morphotype of tyrannosauroid from Appalachia, suggesting greater diversity of the clade on the landmass. Because of this, tyrannosaur diversity in the Campanian of Appalachia was compared to the diversity of tyrannosaurs in Laramidia during the same period to analyze the similarities and differences between the biogeography of tyrannosaurs on each landmass. The results suggest that Appalachian non-tyrannosaurid tyrannosauroids experienced a similar amount of diversity to tyrannosaurids in Laramidia during the Campanian.


PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e4123 ◽  
Author(s):  
Chase D. Brownstein

During the Late Cretaceous, the continent of North America was divided into two sections: Laramidia in the west and Appalachia in the east. Although the sediments of Appalachia recorded only a sparse fossil record of dinosaurs, the dinosaur faunas of this landmass were different in composition from those of Laramidia. Represented by at least two taxa (Appalachiosaurus montgomeriensis and Dryptosaurus aquilunguis), partial and fragmentary skeletons, and isolated bones, the non-tyrannosaurid tyrannosauroids of the landmass have attracted some attention. Unfortunately, these eastern tyrants are poorly known compared to their western contemporaries. Here, one specimen, the partial metatarsus of a tyrannosauroid from the Campanian Merchantville Formation of Delaware, is described in detail. The specimen can be distinguished from A. montgomeriensis and D. aquilunguis by several morphological features. As such, the specimen represents a potentially previously unrecognized taxon of tyrannosauroid from Appalachia, increasing the diversity of the clade on the landmass. Phylogenetic analysis and the morphology of the bones suggest the Merchantville specimen is a tyrannosauroid of “intermediate” grade, thus supporting the notion that Appalachia was a refugium for relict dinosaur clades.


2020 ◽  
Vol 7 (8) ◽  
pp. 200317 ◽  
Author(s):  
Simon G. Scarpetta

Teiid lizards are well represented in the fossil record and are common components of modern ecosystems in North and South America. Many fossils were referred to the cnemidophorine teiid group (whiptails, racerunners and relatives), particularly from North America. However, systematic interpretations of morphological features in cnemidophorines were hampered by the historically problematic taxonomy of the clade, and the biogeography and chronology of cnemidophorine evolution in North America is poorly understood from the fossil record. Few fossil cnemidophorines were identified with an apomorphy-based diagnosis, and there are almost no fossil cnemidophorines that could be used to anchor node calibrations. Here, I describe a cnemidophorine from the Miocene Ogallala Group of Nebraska and diagnose the fossil using apomorphies. In that process, I clarify the systematic utility of several morphological features of cnemidophorine lizards. I refer the fossil to the least inclusive clade containing Aspidoscelis , Holcosus and Pholidoscelis . The most conservative minimum age of the locality of the fossil is a fission-track date of 6.3 Ma, but mammal biochronology provides a more refined age of 9.4 Ma, which can be used as a minimum age for the crown cnemidophorine clade in divergence time analyses. The fossil indicates that a cnemidophorine lineage that does not live in Nebraska today inhabited the area during the Miocene. I refrain from naming a new taxon pending discovery of additional fossil material of the lineage to which the fossil belonged.


2019 ◽  
Vol 6 (11) ◽  
pp. 191206 ◽  
Author(s):  
Chase Doran Brownstein

The faunal changes that occurred in the few million years before the Cretaceous–Palaeogene extinction are of much interest to vertebrate palaeontologists. Western North America preserves arguably the best fossil record from this time, whereas terrestrial vertebrate fossils from the eastern portion of the continent are usually limited to isolated, eroded postcranial remains. Examination of fragmentary specimens from the American east, which was isolated for the majority of the Cretaceous as the landmass Appalachia, is nonetheless important for better understanding dinosaur diversity at the end of the Mesozoic. Here, I report on two theropod teeth from the Mount Laurel Formation, a lower-middle Maastrichtian unit from northeastern North America. One of these preserves in detail the structure of the outer enamel and resembles the dentition of the tyrannosauroid Dryptosaurus aquilunguis among latest Cretaceous forms in being heavily mediolaterally compressed and showing many moderately developed enamel crenulations. Along with previously reported tyrannosauroid material from the Mt Laurel and overlying Cretaceous units, this fossil supports the presence of non-tyrannosaurid tyrannosauroids in the Campanian–Maastrichtian of eastern North America and provides evidence for the hypothesis that the area was still home to relictual vertebrates through the end of the Mesozoic. The other tooth is assignable to a dromaeosaurid and represents both the youngest occurrence of a non-avian maniraptoran in eastern North America and the first from the Maastrichtian reported east of the Mississippi. This tooth, which belonged to a 3–4 m dromaeosaurid based on size comparisons with the teeth of taxa for which skeletons are known, increases the diversity of the Maastrichtian dinosaur fauna of Appalachia. Along with previously reported dromaeosaurid teeth, the Mt Laurel specimen supports the presence of mid-sized to large dromaeosaurids in eastern North America throughout the Cretaceous.


Phytotaxa ◽  
2016 ◽  
Vol 273 (3) ◽  
pp. 215
Author(s):  
PEDRO PABLO FERRER-GALLEGO ◽  
INMACULADA FERRANDO ◽  
EMILIO LAGUNA

The genus Corema D. Don (1826: 63) (Ericaceae Jussieu 1789: 159) comprises two species. Corema album (Linnaeus 1753: 1022) D. Don (1830: 460) (incl. C. febrifugum Boissier ex Willkomm & Lange 1877: 512) occurs on the west coast of the Iberian Peninsula (subsp. album) from Gibraltar to Finisterre (Willkomm & Lange 1877, Webb 1972, Cabezudo 1987, Villar 1993, Boratyński & Vera de la Puente 1994, López González 2001, Ruiz de la Torre 2006, Gil-López 2011), the Azores (subsp. azoricum Pinto da Silva 1966: 86), and the Mediterranean Basin (Spain, Alicante province, one population) (Solanas 1996, Solanas & Crespo 2001, Serra 2007, Aguilella et al. 2009). Corema conradii (Torrey 1837: 83) Torrey (1842: 1092) occurs on the eastern coast of North America from Newfoundland to New Jersey (Redfield 1884, McEwen 1894, Elisens 2009), and can be distinguished from C. album by its very small fruits which are devoid of fleshiness and covered with elaiosomes (oily appendages associated with ant dispersal) (Redfield 1884, McEwen 1894, Martine et al. 2005). Corema album subsp. azoricum exists on six of the nine islands of the Azores, and below 200 m (Franco 1984) this taxon has been recognized by some authors at the species level as C. azoricum [“azorica”] (Pinto da Silva 1966) Rivas Martínez, Lousã, Fernández Prieto, E. Días, J.C. Costa & C. Aguiar (in Rivas-Martínez, Fernández-González, Loidi, Lousã & Penas 2002: 700).


1996 ◽  
Vol 70 (5) ◽  
pp. 866-871 ◽  
Author(s):  
Stephen K. Donovan ◽  
Clare V. Milsom ◽  
Cornelis J. Veltkamp

Jamaica has the best-known fauna of fossil crinoids of the Antillean islands. Two Cretaceous species have been reexamined on the basis of new material. Lower Cretaceous Apiocrinites sp., previously referred to Austinocrinus n. sp. and first documented from a short pluricolumnal, is now known from brachials and further fragments of column. This is the first millericrinid, and only the second non-isocrinid stalked crinoid, to be identified from the Jamaican and Antillean fossil record. Other ossicles may be derived from the cirri of a comatulid. Applinocrinus cretacea (Bather) is well known from the upper Senonian of England, North America and the West Indies, although Caribbean specimens have not been figured previously. Functional interpretations of the mode of life of Applinocrinus suggest that it was a benthic crinoid, presumably with arms. It lived embedded in the sediment.


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