Date of Award

2002

Degree Name

Biological Sciences

College

College of Science

Type of Degree

M.A.

Document Type

Thesis

First Advisor

Dan K. Evans

Second Advisor

Michael Little

Abstract

Central Mexico is home to numerous species of highly toxic Centruroides scorpions. Two species complexes C. infamatus, (C.L. Koch, 1844), and C. limpidus (Karsch, 1879) typify the complex relationships that exist between and within the complexes. Their existing taxonomic status is based on morphological features such as coloration and morphosculpture. A complete and modern study of these scorpions does not exist, and is needed. In an attempt to clarify the status and relationship between these complexes we initiated a molecular based approach applying mitochondrial gene markers (16S and CO1). This study confirms two divergent clades within C. infamatus; divergence rate estimates their common ancestor’s age as 2-4 Ma for HKY+G+I divergence rate (11.7 ± 0.9 %) and 3-5 Ma for uncorrected p (7.2 ± 0.4 %). Further study is necessary with sampling all over the range of both taxa, to confirm existence of two independent study also suggests that more than one ancient monophyletic lineage (possibly, more than one species) exist within currently accepted Centruroides limpidus limpidus. The type locality of Centruroides limpidus is Puebla, which lies in the same geographic area as Guerrero. Thus, we might assume that the Querétaro/Guerrero lineage corresponds to ‘true’ C. limpidus, and that the Balsas Depression populations could belong to another, ‘cryptic’, or ‘sibling’ species. Further, detailed investigations should be done to test these preliminary conclusions: the need for many more populations from the entire range of C. limpidus is needed. Several data sets (mitochondrial and nuclear genes, allozymes, morphology, toxin structure/activity, etc.) could be analyzed to establish the true taxonomic and genetic structure of the populations and species of Centruroides.

Subject

Scorpions - Central Mexico

Subject

Scorpions - Phylogeny

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