New dinosauromorph specimens from Petrified Forest National Park and a global biostratigraphic review of Triassic dinosauromorph body fossils
Author
Marsh, Adam D.
Author
Parker, William G.
text
PaleoBios
2022
37
1
56
journal article
10.5070/P9371050859
0031-0298
DINOSAURIA OWEN, 1842
SENSU
PADIAN AND
MAY, 1993
FIG. 6A–H
Referred specimens and localities
—
PEFO
44475 (
Fig. 6A–D
), proximal ends of left and right femora,
PFV
376: Scour Sandstone,
PFM
;
PEFO
34583 (
Fig. 6E, F
), proximal end of left femur,
PFV
332: Chinde Valley Pin- nacle,
PFM
;
PEFO
34863 (
Fig. 6G, H
), proximal end of left femur,
PFV
215: Zuni Well Mound,
PFM
.
Description and rationale for assignment
—These proximal ends of femora are highly fragmentary and weathered; each of them is broken proximal to the fourth trochanter. Each preserves a mound-like anterior trochanter that remains attached to the shaft proximally (Nesbitt 2011:308-1) (
Fig. 6D
), which is a feature present in Dinosauriformes, e.g.,
Marasuchus lilloensis
(PVL
3871, Sereno and Arcucci 1994: fig. 8b),
Asilisaurus kongwe
(NMT RB159, Nesbitt et al. 2019: fig. 42d), and
Buriolestes schultzi
(ULBRA-PVT280, Cabreira et al. 2016: fig. 1n). Unlike the smooth transition between the ventromedial margin of the femoral head and the shaft (Nesbitt 2011:304-0) found in early dinosauromorphs, e.g.,
Lagerpeton chanarensis
Romer
(1971, PVL 4619) (Nesbitt et al. 2009b: fig. 3a), and
Dromomeron romeri
(GR 218, Nesbitt et al. 2009b: fig. 1a) and the ventral notch (Nesbitt 2011:304-1) present on silesaurid femora (see above), these femora exhibit a concave emargination ventral to the femoral head (Nesbitt 2011:304-2) (
Fig. 6H
), which is apomorphic for dinosaurs, e.g.,
Eocursor parvus
(SAM-PK-K8025, Butler 2009: fig. 15d),
Eodromaeus murphi
Martínez et al.
(2011, PVSJ 562: fig. 2k), and
Herrerasaurus ischigualastensis
(PVSJ 373, Novas 1993: fig. 7c). Thus, we assign these fragmentary proximal ends of femora to
Dinosauria
.