Christopher Griffin

Christopher Griffin
Yale University | YU · Earth & Planetary Sciences

About

16
Publications
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308
Citations
Citations since 2017
13 Research Items
303 Citations
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2017201820192020202120222023020406080
Introduction
I'm interested in how growth and development influence vertebrate evolution, especially during evolutionary radiations and the origin of major clades. I work with both fossils and extant organisms to explore these questions, with a focus on intraspecific variation, convergent evolution, and homology.

Publications

Publications (16)
Article
Full-text available
Intraspecific variation in growth trajectories provides a fundamental source of variation upon which natural selection acts. Recent work hints that early dinosaurs possessed elevated levels of such variation compared to other archosaurs, but comprehensive data uniting body size, bone histology, and morphological variation from a stratigraphically c...
Article
Full-text available
Significant evolutionary shifts in locomotor behaviour often involve comparatively subtle anatomical transitions. For dinosaurian and avian evolution, medial overhang of the proximal femur has been central to discussions. However, there is an apparent conflict with regard to the evolutionary origin of the dinosaurian femoral head, with neontologica...
Article
Full-text available
The vertebrate lineages that would shape Mesozoic and Cenozoic terrestrial ecosystems originated across Triassic Pangaea1–11. By the Late Triassic (Carnian stage, ~235 million years ago), cosmopolitan ‘disaster faunas’ (refs. 12–14) had given way to highly endemic assemblages12,13 on the supercontinent. Testing the tempo and mode of the establishme...
Article
Full-text available
Living birds (Aves) have bodies substantially modified from the ancestral reptilian condition. The avian pelvis in particular experienced major changes during the transition from early archosaurs to living birds1,2. This stepwise transformation is well documented by an excellent fossil record2–4; however, the ontogenetic alterations that underly it...
Article
Full-text available
Morphology forms the most fundamental level of data in vertebrate palaeontology because it is through interpretations of morphology that taxa are identified, creating the basis for broad evolutionary and palaeobiological hypotheses. Assessing maturity is one of the most basic aspects of morphological interpretation and provides the means to study t...
Article
Full-text available
Large body sizes among nonavian theropod dinosaurs is a major feature in the evolution of this clade, with theropods reaching greater sizes than any other terrestrial carnivores. However, the early evolution of large body sizes among theropods is obscured by an incomplete fossil record, with the largest Triassic theropods represented by only a few...
Article
Full-text available
Understanding growth patterns is central to properly interpreting paleobiological signals in tetrapods, but assessing skeletal maturity in some extinct clades may be difficult when growth patterns are poorly constrained by a lack of ontogenetic series. To overcome this difficulty in assessing the maturity of extinct archosaurian reptiles—crocodylia...
Article
Full-text available
Constraint is a universal feature of morphological evolution. The vertebral column of synapsids (mammals and their close relatives) is a classic example of this phenotypic restriction, with greatly reduced variation in the number of vertebrae compared with the sauropsid lineage. Synapsids generally possess only three sacral vertebrae, which articul...
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Full-text available
A recently discovered tyrannosaurid metatarsal IV (SWAU HRS13997) from the uppermost Cretaceous (Maastrichtian) Lance Formation is heavily marked with several long grooves on its cortical surface, concentrated on the bone's distal end. At least 10 separate grooves of varying width are present, which we interpret to be scores made by theropod teeth....
Article
Full-text available
Understanding ontogenetic patterns is important in vertebrate paleontology because the assessed skeletal maturity of an individual often has implications for paleobiogeography, species synonymy, paleobiology, and body size evolution of major clades. Further, for many groups the only means of confidently determining ontogenetic status of an organism...
Article
Full-text available
Typical archosaurian bone tissues and the broad biological features they indicate (e.g., growth rate, basic metabolic strategy) are now well understood. However, definitions, diagnoses, and the paleobiological implications of uncommon osteohistological features, such as medullary bone (in-dicating female reproductive activity) or pathological tissu...
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Full-text available
The sacrum – consisting of those vertebrae that articulate with the ilia – is the exclusive skeletal connection between the hindlimbs and axial skeleton in tetrapods. Therefore, the morphology of this portion of the vertebral column plays a major role in the evolution of terrestrial locomotion. Whereas most extant reptiles only possess the two ples...
Article
Full-text available
Significance Birds—the fastest growing terrestrial vertebrates—develop unlike all other living reptiles. As part of this postnatal developmental mode, birds possess a low amount of intraspecific variation, and the timing of the origin of this low variation is poorly constrained. By studying well-sampled growth series of nonavian dinosaurs and their...
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Full-text available
Netrin-1 is a highly conserved, pleiotropic signaling molecule that can serve as a neuronal chemorepellent during vertebrate development. In vertebrates, chemorepellent signaling is mediated through the tyrosine kinase, src-1, and the tyrosine phosphatase, shp-2. Tetrahymena thermophila has been used as a model system for chemorepellent signaling b...
Article
Full-text available
The ontogeny of early-diverging dinosauromorphs is poorly understood because few ontogenetic series from the same species-level taxon are known and what is available has not been extensively documented. The large numbers of skeletal elements of the silesaurid Asilisaurus kongwe recently recovered from Tanzania provide an opportunity to examine the...

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Project (1)
Project
We are working to describe some recently discovered tooth marks on a dinosaur bone from the Lance Formation, WY.