Topic
Hydrosaurus
About: Hydrosaurus is a research topic. Over the lifetime, 3 publications have been published within this topic receiving 287 citations.
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TL;DR: Three historical events may be responsible for the sharp faunal barrier between Southeast Asia and Australia-New Guinea, known as Wallace's line: primary vicariance caused by plate separations, secondary contact of Southeast Asian plates with Eurasia, leading to dispersal from Eurasia into Southeast Asia, and introduction of different biotic elements to Asia by way of separate Gondwanan plates.
Abstract: A phylogenetic tree for acrodont lizards (Chamaeleonidae and Agamidae) is established based on 1434 bases (1041 informative) of aligned DNA positions from a 1685-1778 base pair region of the mitochondrial genome. Sequences from three protein-coding genes (ND1, ND2, and COI) are combined with sequences from eight intervening tRNA genes for samples of 70 acrodont taxa and two outgroups. Parsimony analysis of nucleotide sequences identifies eight major clades in the Acrodonta. Most agamid lizards are placed into three distinct clades. One clade is composed of all taxa occurring in Australia and New Guinea; Physignathus cocincinus from Southeast Asia is the sister taxon to the Australia-New Guinea clade. A second clade is composed of taxa occurring from Tibet and the Indian Subcontinent east through South and East Asia. A third clade is composed of taxa occurring from Africa east through Arabia and West Asia to Tibet and the Indian Subcontinent. These three clades contain all agamid lizards except Uromastyx, Leiolepis, and Hydrosaurus, which represent three additional clades of the Agamidae. The Chamaeleonidae forms another clade weakly supported as the sister taxon to the Agamidae. All eight clades of the Acrodonta contain members occurring on land masses derived from Gondwanaland. A hypothesis of agamid lizards rafting with Gondwanan plates is examined statistically. This hypothesis suggests that the African/West Asian clade is of African or Indian origin, and the South Asian clade is either of Indian or Southeast Asian origin. The shortest tree suggests a possible African origin for the former and an Indian origin for the latter, but this result is not statistically robust. The Australia-New Guinea clade rafted with the Australia-New Guinea plate and forms the sister group to a Southeast Asian taxon that occurs on plates that broke from northern Australia-New Guinea. Other acrodont taxa are inferred to be associated with the plates of Afro-Arabia and Madagascar (Chameleonidae), India (Uromastyx), or southeast Asia (Hydrosaurus and Leiolepis). Introduction of different biotic elements to Asia by way of separate Gondwanan plates may be a major theme of Asian biogeography. Three historical events may be responsible for the sharp faunal barrier between Southeast Asia and Australia-New Guinea, known as Wallace's line: (1) primary vicariance caused by plate separations; (2) secondary contact of Southeast Asian plates with Eurasia, leading to dispersal from Eurasia into Southeast Asia, and (3) dispersal of the Indian fauna (after collision of that subcontinent) to Southeast Asia. Acrodont lizards show the first and third of these biogeographic patterns and anguid lizards exhibit the second pattern. Modern faunal diversity may be influenced primarily by historical events such as tectonic collisions and land bridge connections, which are expected to promote episodic turnover of continental faunas by introducing new faunal elements into an area. Repeated tectonic collisions may be one of the most important phenomena promoting continental biodiversity. Phylogenetics is a powerful method for investigating these processes.
277 citations
TL;DR: This integrative study characterizes a conservation urgency of particular significance: the genetically distinct sailfin lizards of the Bicol faunal region, with suitable habitat virtually unprotected, and clear evidence of heavy exploitation for illegal trade.
16 citations
TL;DR: A systematic investigation brings the number of recognized species within the genus Hydrosaurus to five and resurrects the taxa celebensis Peters, 1872 and microlophus Bleeker, 1860 from the synonymy of H. amboinensis, which in turn is restricted to the central Moluccas and New Guinea.
Abstract: Currently three different species are recognized within the Southeast Asian agamid genus Hydrosaurus: H. amboinensis (Schlosser, 1768) from Ambon, Seram, Sulawesi and New Guinea, H. pustulatus (Eschscholtz, 1829) from the Philippines and H. weberi Barbour, 1911 from Halmahera and adjacent islands. Historically, two additional species were described from the island of Sulawesi, but were synonymized with H. amboinensis more than a century ago and have been treated as such in most subsequent publications. In order to revise the taxonomy and diversity of these enigmatic agamid lizards, we examined the corresponding type specimens and additional material originating from Sulawesi and compared them to photographs of live specimens from field trips. Due to differences in colour pattern and scalation characters, we resurrect the taxa celebensis Peters, 1872 and microlophus Bleeker, 1860 from the synonymy of H. amboinensis, which in turn is restricted to the central Moluccas and New Guinea. Hence, Sulawesi is currently the only known island within the genus' range to be inhabited by two different species of sailfin lizards. Our systematic investigation brings the number of recognized species within the genus Hydrosaurus to five.
7 citations