Systematics and biogeography of the new world scorpion genus Centruroides marx, 1890 (Scorpiones: Buthidae)
Item
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Title
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Systematics and biogeography of the new world scorpion genus Centruroides marx, 1890 (Scorpiones: Buthidae)
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Identifier
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d_2009_2013:48f743aebd30:11016
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identifier
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11278
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Creator
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Esposito, Lauren A.,
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Contributor
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Lorenzo Prendini
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Date
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2011
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Language
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English
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Publisher
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City University of New York.
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Subject
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Zoology | Systematic biology | Biogeography | Scorpions | Systematics
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Abstract
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Background: The New World scorpion genus Centruroides Marx, 1890 (family Buthidae Koch, 1837) is a morphologically diverse and highly venomous taxon. Centruroides is among the most complex scorpion genera in the New World, comprising 71 described species and 5 subspecies in addition to several undescribed species. These scorpions are sexually dimorphic, the males typically exhibiting elongation of the metasoma and telson and longer, more slender pedipalp chelae. The greatest diversity of Centruroides occurs in Mexico; however the genus is distributed from the southern United States into northern South America and the Galapagos, and throughout the Caribbean. The genus includes the only scorpions of medical importance in North America, with six species that are potentially lethal to humans.;Historical Taxonomic Problems: Centruroides species are problematic for systematists for several reasons. The morphological characters traditionally used (morphometrics and color) often overlap between closely related species or are vaguely defined, and many have been shown to vary within populations making the identification of species difficult. Many researchers have studied and revised small groups of species, but no comprehensive modern taxonomic treatment of the entire genus exists. The positions of Centruroides within the New World buthids, its relationship to its putative sister genus Rhopalurus Thorell, 1890, and its monophyly have never been tested. Few modern analytical methods have been applied to the genus, a problem that extends to both phylogenetic and biogeographical analysis.;Aims: The broader vision of this dissertation project was to investigate and evaluate the systematics and biogeographic patterns that have resulted in one of the largest, least understood and most medically important genera of New World buthid scorpions. This was accomplished through: (1) conducting fieldwork in regions of Centruroides diversity to gather fresh material for morphological and genetic studies; (2) conducting molecular and morphological phylogenetic analyses to test the monophyly of the genus and determine its relationship to other New World buthid genera, identify the major clades and test the validity of the currently hypothesized species groups; (3) testing biogeographic hypotheses to explain the present distributions and species diversity. Conclusions: The buthid subfamily Rhopalurusinae comprising Centruroides, Rhopalurus, Physoctonus and Troglorhopalurus is supported with molecular and morphological evidence. Rhopalurus is paraphyletic with respect to Centruroides, forming two clades: one endemic to South America and the other endemic to the Greater Antilles. Centruroides is monophyletic, sister to the Greater Antilles Rhopalurus . The genus Heteroctenus Pocock, 1893 is resurrected for the Greater Antilles Rhopalurus species. Centruroides contains four, geographically delimited clades: a Caribbean clade, a North American clade, a Mesoamerican clade, and a Yucatan/Chortis block clade. A fossil-calibrated phylogeny of New World buthids dates the separation of the Greater Antilles Rhopalurus + Centruroides at {lcub}29.0, 42.9{rcub} mya. Ancestral distribution reconstruction infers this node to be South America and the Greater Antilles. The ancestral distribution of Centruroides is inferred to be North America. Both the dating and the ancestral distribution reconstruction are congruent with the GAARlandia hypothesis, which has been proposed to explain similar disjunct distributions in large mammals. The Greater Antilles distributed sister taxon of Centruroides provides evidence for a Caribbean ancestor for the genus, which subsequently colonized North and Meso-America and re-colonized the Caribbean.
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Type
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dissertation
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Source
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2009_2013.csv
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degree
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Ph.D.
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Program
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Biology
