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Arundelemys dardeni is an Early Cretaceous paracryptodire known from a single, incomplete, but generally well-preserved skull. Phylogenetic hypotheses of paracryptodires often find Arundelemys dardeni as an early branching baenid. As such, it has a central role in understanding the early evolution of the successful clade Baenidae, which survived the Cretaceous–Paleogene mass extinction, as well as the diversification of Paracryptodira into its subclades, which recent research suggests to perhaps include helochelydrids, compsemydids, pleurosternids, and baenids. Computer tomography scans of the holotype material that were produced for the initial description of Arundelemeys dardeni reveal several errors in the initial anatomical description of the species, which we correct based on element-by-element segmentation. In addition, we provide entirely novel anatomical information, including descriptions of several previously undescribed cranial bones, the endosseous labyrinth, and the cranial scutes, the latter of which are unknown for most paracryptodires. We provide an interpretation of cranial scutes which homologizes the scutes of Arundelemys dardeni with those of other stem turtles.
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The Tiny Skull of the Peruvian Gecko Pseudogonatodes barbouri (Gekkota: Sphaerodactylidae) Obtained via a Divide-And-Conquer Approach to Morphological Data Acquisition
The Peruvian sphaerodactyl gecko, Pseudogonatodes barbouri, is among the smallest reptile species in South America. Morphological information about this species, or even the genus, is limited. In this study, we produced a bone-by-bone description from the skull and atlantoaxial complex to contribute new phenotypic information about this poorly known lizard. To achieve this objective, we employed a divide-and-conquer approach in which each author digitally isolated one or two bones from the skull and produced a written description of these elements, thereby reducing 3D imaging processing and description to a fraction of time. In addition to a reduced phalanx in the fourth toe of both the hand and foot, the genus is characterized by having nasal bones with a broad lateral wing, an ectopterygoid that clasps the pterygoid, and an anterior shifting of the paroccipital process and as consequence the position of the quadrate, and squamosal not participating in the quadrate suspension. There are also modifications in fenestration and foramina and a trend towards synostosis of the jaw bones (e.g., coronoid + splenial, compound bone + surangular). Pseudogonatodes bears four long processes on the intercentrum of the axis; which is a character of New World sphaerodactyls.
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- Award ID(s):
- 1657656
- PAR ID:
- 10092192
- Date Published:
- Journal Name:
- South American Journal of Herpetology
- Volume:
- 13
- Issue:
- 2
- ISSN:
- 1808-9798
- Page Range / eLocation ID:
- 102
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.2994/SAJH-D-17-00113.1
