DISCOVERY OF A SKULL OF A SMALL THEROPOD 
DINOSAUR (CF. COELOPHYSIS) FROM THE LOWER 
NEW 
HAVEN FORMATION OF THE HARTFORD BASIN, 
CONNECTICUT, USA (LATE TRIASSIC, NEWARK 
SUPERGROUP)

	OLSEN, P. E., Lamont-Doherty Earth Observatory of 	
		Columbia University,  Palisades, New York, 10964
	NORELL, M. A., Department of Vertebrate Paleontology, 	
		American Museum of Natural History, Central Park 
		West at 79th Street, New York, NY 10024-5192
	SUES, H.-D., Department of Vertebrate Paleontology, Royal 
		Ontario Museum, 100 Queen's Park, Toronto, Ontario  
		M5S 2C6, Canada
	McDONALD, N. G., Department of Earth and Environmental 
		Sciences, Wesleyan University, Middletown, CT 	
		06459

Dinosaur skeletal remains are regarded as particularly rare in the 
Triassic age portion of the Newark Supergroup, despite the extreme 
abundance of dinosaur footprints in some basins. In March, 1995, 
however, most of a skull of a small theropod dinosaur was found in 
the lower New Haven Formation, in Cheshire, CT. The skull, still 
under preparation at the time of writing, is long and pointed, with a 
very large antorbital fenestra, and recurved teeth that are thickly oval 
in cross section. In its overall form, it is comparable to small 
specimens of the Ghost Ranch Coelophysis from 
the Rock Point Formation of the Chinle Group at Ghost Ranch, NM 
(see Hunt and Lucas, 1991). Further preparation should allow a more 
definitive identification. This is the first skull of a Triassic theropod 
dinosaur from eastern North America, and the first dinosaur skull of 
any sort from the Newark Supergroup found since the 19th century. 
Intriguingly, the matrix containing the skull also contains what seems 
to be an isolated sphenodontian premaxilla.
	The source of the material is an exposure in Cheshire 
consisting of gray, buff, and brown meandering river deposits 
alternating with red overbank deposits (McInerney (1993) and Horne 
et al., 1993). The skull was found in situ in an upright position in red 
sandy mudstone. The mudstone is intensely bioturbated by Scoyenia 
burrows and roots, and it passes upward into caliche-bearing red 
sandy mudstone comprising a typical New Haven Formation caliche 
paleosol profile. A pollen and spore assemblage from the basal part of 
the New Haven Formation (Cornet, 1977) constrains the age of the 
new skull to the Late Triassic, almost certainly to the Norian. 
	Previously described reptile taxa from the New Haven Formation include the type of Stegomus arcuatus (Marsh, 1896) , an isolated, fragmentary scapula of a phytosaur ("Belodon validus": Marsh, 1893), a small sphenodonian skull (Sues and Baird, 1993), and an excellent skull and partial skeleton of Hypsognathus fenneri (Ostrom, 1967). The relative age relations of these taxa, apart from being Norian or Rhaetian, are unknown.
	The bone-bearing fluvial facies at Cheshire is one of the most 
common types of fluvial facies in the Newark Supergroup, and it is 
noteworthy that a similar suite of lithologies in the Durham subbasin 
of the Deep River basin in North Carolina recently produced several 
partial skeletons of suchian archosaurs (Olsen et. al, 1996). Because 
this facies is almost never prospected for fossils in the Newark 
Supergroup, the dearth of skeletal remains in Newark Supergroup 
Triassic age strata may be more apparent than real.

Cornet, W. B., 1977, The Palynostratigraphy and Age of the Newark 
Supergroup. [Ph.D., thesis], Department of Geosciences, Pennsylvania 
State University, State College, Pennsylvania, 505 p.
Horne, G. S., McDonald, N. G., LeTourneau, P. M. and de Boer, J. Z., 
1993, Paleoenvironmental traverse across the early Mesozoic Hartford 
rift basin, Connecticut, In Cheney, J. T., Hepburn, J. C., Field trip 
guidebook for the northeastern United States, Boston GSA, 
Contribution - Geology Department, University of Massachusetts, 
v.67, Vol. 2, p. P.1-P.26.
Hunt, A. and Lucas, S., 1991, Rioarribasaurus a new name for a Late 
Triassic dinosaur from New Mexico (USA). Palaeontologische 
Zeitschrift, v. 65, 191-198.
Marsh, O. C., 1893, Restoration of Anchisaurus. American Journal of 
Science, 3rd ser., v. 45, p. 169-170.
Marsh, O. C., 1896, A new belodont reptile (Stegomus) from the 
Connecticut River sandstone. American Journal of Science,  4th ser., 
v. 2, p. 59-62.
McInerney, D. P., 1993, Fluvial architecture and contrasting fluvial 
styles of the lower New Haven Arkose and mid-upper Portland 
Formation, early Mesozoic Hartford Basin, central Connecticut. M.S., 
thesis, Department of Geology an Geography, University of 
Massachusetts; Amherst, 271 p.
Olsen, P. E., 1980, Comparison of the vertebrate assemblages from 
the Newark and Hartford basins (Early Mesozoic, Newark 
Supergroup) of eastern North America: In Jacobs, L. L. (ed.), Aspects 
of Vertebrate History. Flagstaff, Museum of Northern Arizona Press, 
p. 35-53.
Ostrom, J. H., 1967, [on the discovery of Hypsognathus in 
Connecticut]. Discovery, v. 3, p. 59.
Sues, H.-D. and Baird, D.,  1993, A skull of a Sphenodontian 
lepidosaur from the New Haven Arkose  (Upper Triassic Norian) of 
Connecticut. Journal of Vertebrate Paleontology, v.13, n.3, p.370-372.


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