Jason P. Downs
Academy of Natural Sciences of Drexel University
19 Papers
21 Citations
Jason P. Downs is an academic researcher from Academy of Natural Sciences of Drexel University. The author has contributed to research in topics: Devonian & Sarcopterygii. The author has an hindex of 9, co-authored 17 publications. Previous affiliations of Jason P. Downs include Yale University & Swarthmore College.
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Papers
Early evolution of vertebrate skeletal tissues and cellular interactions, and the canalization of skeletal development
TL;DR: A synthesis of leading hypotheses for the emergence of the four skeletal tissue types that define the present state of skeletal tissue diversity in vertebrates finds that bone, dentine, enamel and cartilage do appear to be fundamentally distinct from their first inceptions, although why a higher diversity of tissue structural grades exists within these types early in vertebrate phylogeny is a question that remains to be addressed.
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Skeletal histology of Bothriolepis canadensis (Placodermi, Antiarchi) and evolution of the skeleton at the origin of jawed vertebrates.
TL;DR: The results of this work support the interpretation that the external skeleton of Bothriolepis canadensis is comprised exclusively of cellular dermal bone tissue, and highlight the importance of anatomical and ontogenetic context in the interpretation of fossil tissues.
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Mass Mortality of Juvenile Antiarchs (Bothriolepis sp.) from the Catskill Formation (Upper Devonian, Famennian Stage), Tioga County, Pennsylvania
Jason P. Downs,Jason P. Downs,Katharine E. Criswell,Katharine E. Criswell,Edward B. Daeschler +4 more
- 01 Oct 2011
TL;DR: In this paper, a sample of very small Bothriolepis from the Catskill Formation (Upper Devonian, Famennian Stage) in Tioga County, Pennsylvania, USA was analyzed.
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New description and diagnosis of Hyneria lindae (Sarcopterygii, Tristichopteridae) from the Upper Devonian Catskill Formation in Pennsylvania, U.S.A.
TL;DR: A near-complete cranial specimen collected near Red Hill that was originally diagnosed as Eusthenodon wängsjöi by Thomson (1976) is revised as Hyneria cf.
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Long-bone development and life-history traits of the Devonian tristichopterid Hyneria lindae
Viktoriia Kamska,Edward B. Daeschler,Jason P. Downs,Per Ahlberg,Paul Tafforeau,Sophie Sanchez +5 more
TL;DR: The bone histology of H. lindae would favour the hypothesis that a slow long-bone development could be a general character for stem tetrapods, and the lines-of-arrested-growth pattern and late ossification of specimen ANSP 21483 suggest that it probably had a long juvenile stage before reaching sexual maturity.
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