Topic
Crocodilurus
About: Crocodilurus is a research topic. Over the lifetime, 17 publications have been published within this topic receiving 173 citations.
Papers
Journal Article•
TL;DR: The preliminary observations suggest that ontogenetic change is an important source of variation in S. crocodilurus and provide preliminary observations on morphological change of the braincase through ontogeny.
Abstract: We review the literature and provide a detailed description of the braincase, cephalic osteoderms, and the inner ear cavity of the rare Southeast Asian lizard Shinisaurus crocodilurus. In addition to standard dry skeletal preparations, we used X-ray computed tomography scans of an adult and juvenile specimen to provide novel illustrations and digital animations of its anatomical systems. We provide the first detailed description and illustration of the orbitosphenoids, cephalic osteoderms, and inner ear passages in S. crocodilurus, clarify the presence or absence of previously reported anatomical features of the braincase, and provide preliminary observations on morphological change of the braincase through ontogeny. Orbitosphenoids are present and ossified in S. crocodilurus at a relatively early stage of postnatal development. A fully developed and ossified parasphenoid rostrum is present in our youngest dried specimen, but appears to be reduced or broken in many adult specimens. The osteoderms of adult S. crocodilurus are robust and widely distributed across the dorsal surface of the head, but they do not co-ossify with underlying dermal bones. Osteoderms are absent in our juvenile specimens. Calcified endolymph is present in both adult and juvenile specimens, but is more extensive in the juvenile. Our preliminary observations suggest that ontogenetic change is an important source of variation in S. crocodilurus.
80 citations
TL;DR: The basal divergence between two clades of S. crocodilurus in China may have been caused by the formation of the Pearl River system, and a population expansion in one of these clades is found.
Abstract: The Chinese crocodile lizard Shinisaurus crocodilurus is a critically endangered species, listed in Appendix II of CITES. Its populations and habitat in China have undergone significant changes in recent years. Understanding the genetic variability and phylogeography of this species is very important for successful conservation. In this study, samples were taken from 11 wild ponds and two captive populations in China. We sequenced mitochondrial CYTB, partial ND6, and partial tRNA-Glu and genotyped 10 microsatellite loci. Our analyses of these data showed low genetic variability, no strong isolation caused by distance, and a lack of a phylogeographic structure in this species. Based on our results, the basal divergence between two clades of S. crocodilurus in China may have been caused by the formation of the Pearl River system. We found a population expansion in one of these clades. Microsatellite analysis indicated the presence of three clusters, separated by significant genetic differences. We found that most individuals in the two captive populations were from the Luokeng (Guangdong) and Guangxi wild source populations, respectively.
26 citations
Journal Article•
TL;DR: In this paper, the authors provided the first estimation of the population size of S. crocodilurus in Vietnam, which is essential baseline data for future conservation strategies, highlighting the urgent need to improve the conservation activities for this species in its natural habitats and suggesting means for a translocation program to restore (minimum viable sizes of) the wild populations in northern Vietnam.
Abstract: The Crocodile Lizard Shinisaurus crocodilurus Ahl, 1930 is a monotypic species, with a distribution range restricted to small and isolated areas in southern China and northern Vietnam. Habitat destruction and illegal poaching are the main causes of alarming population declines and even extinction of some wild populations in China. While the Chinese population was estimated to comprise only 950 individuals in 2004, the existing status of the Vietnamese population remains unknown, since its discovery in 2002. Our work provides the first estimation of the population size of S. crocodilurus in Vietnam, which is essential baseline data for future conservation strategies. Our field research revealed a dramatically small population size of less than 100 mature individuals. This value falls substantially below published threshold sizes of several thousand individuals, required for the long-term persistence of a species. Our research highlights the urgent need to improve the conservation activities for this species in its natural habitats and suggests means for a translocation program to restore (minimum viable sizes of) the wild populations in northern Vietnam.
18 citations
1 Jan 2008
TL;DR: Preliminary morphological comparisons between Chinese and Vietnamese Shinisaurus representatives showed no significant differences that would justify a separate taxonomic status of the single known Vietnamese population, and first mitochondrial DNA sequence comparisons showed very low differentiation therefore, being likely to represent the same taxon.
Abstract: Preliminary morphological comparisons between Chinese and Vietnamese Shinisaurus representatives showed no significant differences that would justify a separate taxonomic status of the single known Vietnamese population. Also first mitochondrial DNA sequence comparisons showed very low differentiation therefore, being likely to represent the same taxon. In addition, we provide further information about the habitat, and preliminary data concerning the reproduction and feeding ecology of Vietnamese S. crocodilurus. We further stress biogeographical and conservational aspects of the endangered species in Vietnam.
17 citations
TL;DR: High levels of inter-generic variability in sperm ultrastructure within Teiidae produce a data set useful in analyzing relationships between genera and families, which supports the recent splitting of these two lineages into different genera.
Abstract: Sperm ultrastructure of five teiid lizards (Callopistes flavipunctatus, Crocodilurus amazonicus, Dicrodon guttulatum, Dracaena guianensis, and Teius oculatus), and the gymnophthalmid Cercosaura ocellata is described for the first time. Comparisons of sperm ultrastructure among these species and with those of previously examined teiids and gymnophthalmids revealed that the two groups of Teiioidea (Gymnophthalmidae and Teiidae), and the two subfamilies of Teiidae (Teiinae and Tupinambinae) could be distinguished on the basis of sperm ultrastructure data. Significant differences in sperm dimensions between Cnemidophorus and Aspidoscelis support the recent splitting of these two lineages into different genera. Our results revealed high levels of inter-generic variability in sperm ultrastructure within Teiidae, which produces a data set useful in analyzing relationships between genera and families. In phylogenetic analyses, however, sampling multiple species within teiid genera is essential and recording sperm measurements may profitably complement qualitative ultrastructural characters, maximizing the information content of these structures.
16 citations
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2021 | 2 |
| 2017 | 1 |
| 2015 | 1 |
| 2014 | 2 |
| 2012 | 1 |
| 2011 | 1 |