Morphology of the nasal capsule of <i>Heloderma suspectum</i> with comments on the systematic position of helodermatids (Squamata: Helodermatidae)

Bernstein, Peter S.

doi:10.1046/j.1463-6395.1999.00020.x

Cited by 18 publications

(29 citation statements)

References 16 publications

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“…These are 58 (0) Varanidae is typically considered to include extant Varanus, Lanthanotus, and all descendants of their last common ancestor (Pregill et al, 1986;Estes et al, 1988;Pianka, 1995;Lee, 1998;Bernstein, 1999;Conrad, 2004Conrad, , 2008. The current analysis recovers five unambiguous synapomorphies for Varanidae including Aiolosaurus.…”

Section: Systematic Resultsmentioning

confidence: 53%

Re-assessment of varanid evolution based on new data from Saniwa ensidens Leidy, 1870 (Squamata, Reptilia)

Conrad¹,

Rieppel²,

Grande³

2008

Am Museum Novitates

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Saniwa ensidens is a pivotal taxon for understanding varanid evolution. A complete specimen of Saniwa ensidens was recently described, offering important new insights into the morphology of this taxon. We apply these new data to a broader-scale study of squamate relationships in order to understand the phylogenetic position of Saniwa ensidens and of varanids more generally. Among the other fossils included in our analysis were the Eocene taxon ''Saniwa'' feisti, the Miocene Varanus rusingensis, and the giant Pleistocene varanid Megalania prisca. We compare the phylogenetic hypothesis from our analysis of morphology with a recent molecular-based hypothesis and find numerous differences in the phylogenetic relationships within Varanus. We constrained our morphological data set to the phylogenetic pattern presented by the molecular data to further analyze the possible phylogenetic relationships of the fossil taxa. Our analyses show that Saniwa ensidens is the sister taxon to crown-group Varanus and that ''Saniwa'' feisti is a basal member of the varanid lineage, not closely related to Saniwa ensidens. Both Varanus rusingensis and Megalania prisca are members of the crown radiations of Varanus.

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Section: Systematic Resultsmentioning

confidence: 53%

Re-assessment of varanid evolution based on new data from Saniwa ensidens Leidy, 1870 (Squamata, Reptilia)

Conrad¹,

Rieppel²,

Grande³

2008

Am Museum Novitates

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“…The septomaxilla is a paired bone that covers the vomeronasal apparatus dorsally (syn. organ of Jacobson) as in most squamates (Bernstein, 1999). In lateral view, the space occupied by the vomeronasal apparatus (syn.…”

Section: Description Of Isolated Bones Dermatocraniummentioning

confidence: 99%

“…A dorsally expanded, convex septomaxilla reflects an enlarged Jacobson's organ and is a synapomophy of the Scleroglossa . In iguanids, agamids, and chamaeleonids the vomeronasal apparatus is often reduced apparently due to the diminished importance of olfactory stimuli in the arboreal habitat (Pratt, 1948;Hallermann, 1994;Bernstein, 1999). For example in the iguanian Pristidactylus the vomeronasal apparatus is poorly developed and the septomaxillae are small and flat (Montero et al, 2004).…”

Section: Skull Bonesmentioning

confidence: 99%

Skull anatomy of the miniaturized gecko Sphaerodactylus roosevelti (Squamata: Gekkota)

Daza

Abdala

Thomas

et al. 2008

Journal of Morphology

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A detailed description of the skull and jaw of the gecko Sphaerodactylus roosevelti is presented. The bones are described articulated and isolated with special consideration given to the type of suture among joining elements. S. roosevelti was compared with 109 gekkotan species to evaluate the osteological variation and to find characters for cladistic analysis. Changes in the skull associated with the miniaturization process are discussed within the sphaerodactylid geckos. A noticeable increase of overlapping sutures was observed in the snout of the smallest sphaerodactylids compared to other gekkotans. This pattern is convergent with that in miniaturized pygopodids and may be attributed to adaptations for decreasing mechanical resistance of the cranium during feeding or burrowing. New cranial characters support Sphaerodactylinae as a monophyletic group and should be useful for resolving questions such as their relationship with other gekkotans.

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“…5C). Medially, the crista transversalis would have met the sheet‐like cartilaginous lamina transversalis anterior (Oelrich, 1956; Bernstein, 1999). It would have been continuous dorsally with the membranous tissue surrounding the portion of the cupula that is folded under the main body of the nasal capsule (B.S.…”

Section: Resultsmentioning

confidence: 99%

Cranial osteology of Exostinus serratus (Squamata: Anguimorpha), fossil sister taxon to the enigmatic clade Xenosaurus

Bhullar¹

2010

Zoological Journal of the Linnean Society

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Within the squamate clade Anguimorpha, Xenosaurus is an enigmatic taxon combining several apparently primitive features with a highly specialized set of autapomorphies. This combination makes the fossil record along the Xenosaurus stem particularly important for resolving the relationships of Xenosaurus with other anguimorphs, and between species of Xenosaurus. Exostinus serratus Cope, 1873 from the Oligocene of the western United States is currently hypothesized to be the immediate sister taxon to Xenosaurus. The cranial osteology of this pivotal taxon is described here for the first time from all known material, using high-resolution X-ray computerized tomography (CT) scanning to visualize individual elements. Exostinus serratus displays a mosaic of ancestral anguimorph features that are transformed in Xenosaurus, as well as unique synapomorphies shared with Xenosaurus. The region of the external nares is less transformed than in Xenosaurus, as are the general proportions of the bones surrounding the cartilaginous nasal capsule. However, the forms of the teeth and of the osteodermal sculpture, as well as several details of maxillary and mandibular morphology, are distinctly Xenosaurus-like. Several autapomorphies are also present, including an abbreviated tooth row and an unusually wide palatal shelf of the maxilla. An understanding of the ways in which the non-ossified tissues of the head influenced the development of the bones is crucial to interpreting their morphology. Furthermore, subtle anatomical features often provide important comparative information, and are emphasized herein.

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Morphology of the nasal capsule of Heloderma suspectum with comments on the systematic position of helodermatids (Squamata: Helodermatidae)

Cited by 18 publications

References 16 publications

Re-assessment of varanid evolution based on new data from Saniwa ensidens Leidy, 1870 (Squamata, Reptilia)

Re-assessment of varanid evolution based on new data from Saniwa ensidens Leidy, 1870 (Squamata, Reptilia)

Skull anatomy of the miniaturized gecko Sphaerodactylus roosevelti (Squamata: Gekkota)

Cranial osteology of Exostinus serratus (Squamata: Anguimorpha), fossil sister taxon to the enigmatic clade Xenosaurus

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