Date of Award


Degree Name

Biological Sciences


College of Science

Type of Degree


Document Type


First Advisor

Victor Fet


Morphological characters used in scorpion systematics are limited to a few reliable structures. The most recent high-level, comprehensive revision of scorpion phylogeny, 38 of the 105 morphological characters were based on trichobothria – socketed mechanosensory seta (Soleglad & Fet, 2003). Other microstructures such as granules, setae, spines, etc. have been found in scorpions but their use for taxonomy was limited. In an effort to better understand the complex relationships among these ancient but similar looking animals, we attempted to first locate new microstructures and then assess their reliability and variability thus determining the levels at which they are diagnostic. The initial surveys were conducted on representatives of each of the twelve extant families using scanning electron microscopy (SEM). After identifying a new structure, comparisons between the families were made, and statistics were applied when warranted. The constellation array, found on the distal end of the fixed chelal finger in all scorpions, can be examined by counting the number of sensilla present and morphometric analysis. The laterobasal aculear serrations (LAS) were found to be a synapomorphy of the family Vaejovidae and exhibited too much intraspecific variability to be diagnostic at lower levels. In a number of families, including Vaejovidae, serrula was found in groups that were documented as lacking the structure. The limited resolution of dissecting microscopes and three-dimensional nature of these structures make the use of a SEM essential to the advancement of scorpion, as well as other arthropod, systematics and to our overall understanding of biodiversity.


Scorpions - Morphology.

Scorpions - Taxonomy.

Scorpions - Phylogeny.