David J. Varricchio
Montana State University
73Publications
26H-index
2,335Citations
Publications 73
Newest
Published on Apr 24, 2018in PALAIOS 1.70
Jason R. Moore (University of New Mexico), David J. Varricchio26
Estimated H-index: 26
(Montana State University)
ABSTRACT Fluvial transport is recognized as a common manner by which bone assemblages forming in or near moving water can be taphonomically modified. Here we study an assemblage of 38 cow carcasses, killed during a mass-mortality event and deposited in a fluvial system (the Yellowstone River of eastern Montana), over the course of three years. Seven of the 38 carcasses were observable throughout the study, allowing assessment of patterns of disarticulation and element loss with respect to time a...
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Published on Dec 1, 2018in Scientific Reports 4.12
David J. Varricchio26
Estimated H-index: 26
(Montana State University),
Martin Kundrát11
Estimated H-index: 11
(University of Pavol Jozef Šafárik),
Jason Hogan1
Estimated H-index: 1
(Montana State University)
Non-avian dinosaurs such as oviraptorosaurs and troodontids share several important reproductive characters with modern birds, including eggshell microstructure and iterative egg production. Nevertheless, debate exists concerning their incubation strategies. Here we estimate incubation period for the troodontid, Troodon formosus, by examining a near-term embryonic tooth. Synchrotron scanning and histologic thin sections allowed counting of daily (von Ebner) growth lines. The tooth preserves 31 i...
1 Citations Source Cite
Published on Nov 19, 2018in Historical Biology 1.25
Ashley L. Ferguson (Idaho State University), David J. Varricchio26
Estimated H-index: 26
(Montana State University),
Alex J. Ferguson (University of Idaho)
ABSTRACTNesting localities of extant birds and reptiles may provide taphonomic models for interpreting nesting sites of ancient archosaurs. Here we describe assemblages of nesting gulls (Larus delawarensis and L. californicus), American white pelicans (Pelecanus erythrorhynchos), and double-crested cormorants (Phalacrocorax auritus). Seventy nests yielded 2752 skeletal elements and 2308 eggshells. Most material was located inside the nest for gulls and consisted of osteologically mature gull bon...
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Published on May 1, 2017in PALAIOS 1.70
Ashley L. Ferguson2
Estimated H-index: 2
(Montana State University),
David J. Varricchio26
Estimated H-index: 26
(Montana State University)
+ 1 AuthorsFrankie D. Jackson19
Estimated H-index: 19
(Montana State University)
Abstract: Nesting behaviors of extant vertebrates can serve as taphonomic models for interpreting extinct archosaurian reproduction. Past studies have examined birds with open nests and nest-bound young and tortoises with buried nests and precocial young. Here we taphonomically describe nesting sites of two crocodylians, American crocodile (Crocodylus acutus) at Turkey Point, Florida and broad-snouted caiman (Caiman latirostris) from Santa Fe and Chaco provinces, Argentina. Surveys focused on eg...
2 Citations Source Cite
Published on Nov 1, 2017in Cretaceous Research 1.93
Frankie D. Jackson19
Estimated H-index: 19
(Montana State University),
David J. Varricchio26
Estimated H-index: 26
(Montana State University)
Abstract Two closely associated egg types occur at the same locality in the Upper Cretaceous (Maastrichtian) St. Mary River Formation in north central Montana. These specimens represent the first fossil eggs described from this formation. At least fifteen small ovoid eggs or egg portions are scattered through a 25 cm interval of rock. Five significantly larger, round eggs overlie these smaller eggs and are in close proximity to one another on a single bedding plane. The best preserved egg of the...
1 Citations Source Cite
Published on Feb 17, 2017in Historical Biology 1.25
L.J. Krumenacker1
Estimated H-index: 1
(Montana State University),
D. Jade Simon1
Estimated H-index: 1
(Boise State University)
+ 1 AuthorsDavid J. Varricchio26
Estimated H-index: 26
(Montana State University)
AbstractThe record of terrestrial vertebrates in the upper Albian to Cenomanian Wayan Formation of Idaho is sparse, with most fossils recovered belonging to the small orodromine neornithischian Oryctodromeus cubicularis and the maniraptoran ootaxon Macroelongatoolithus carlylei. Here we report on a diversity of theropod forms now recognised from various isolated teeth, vertebrae, eggs and eggshell. Theropods recognised from isolated teeth include a large possible tyrannosauroid, a small tyrannos...
7 Citations Source Cite
Published on Dec 1, 2017in Scientific Reports 4.12
Thomas D. Carr14
Estimated H-index: 14
,
David J. Varricchio26
Estimated H-index: 26
+ 2 AuthorsJason R. Moore3
Estimated H-index: 3
A new species of tyrannosaurid from the upper Two Medicine Formation of Montana supports the presence of a Laramidian anagenetic (ancestor-descendant) lineage of Late Cretaceous tyrannosaurids. In concert with other anagenetic lineages of dinosaurs from the same time and place, this suggests that anagenesis could have been a widespread mechanism generating species diversity amongst dinosaurs, and perhaps beyond. We studied the excellent fossil record of the tyrannosaurid to test that hypothesis....
12 Citations Source Cite
Published on Mar 3, 2016in Journal of Vertebrate Paleontology 2.19
Jamie L. Fearon2
Estimated H-index: 2
,
David J. Varricchio26
Estimated H-index: 26
ABSTRACTTaphonomic and morphological evidence suggests that Oryctodromeus cubicularis, a basal ornithopod dinosaur from the mid-Cretaceous of Montana, constructed burrows by digging with its forelimbs. Reconstruction of the forelimb musculature of Oryctodromeus was carried out using the extant phylogenetic bracket method, with crocodilians and ratites as the extant analogues, aided by the presence of osteological correlates in Oryctodromeus and other ornithopods. Although reconstructions directl...
2 Citations Source Cite
Published on Sep 2, 2016in Journal of Vertebrate Paleontology 2.19
Frankie D. Jackson19
Estimated H-index: 19
,
David J. Varricchio26
Estimated H-index: 26
ABSTRACTDespite over a hundred years of intense paleontological exploration, the terrestrial rocks of the Upper Cretaceous (Maastrichtian) Hell Creek Formation of eastern Montana are remarkable for the absence of fossil eggs. Here, we describe the first fossil egg and additional eggshell fragments from the formation. The two-layered structure of the smooth 1600-µm-thick eggshell of Belonoolithus garbani, oogen. et oosp. nov., permits assignment of the 6 cm × 8 cm egg to Theropoda. Additional the...
8 Citations Source Cite
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