A preliminary assessment of the utility of elongation factor-1alpha in elucidating relationships among basal Mesostigmata.

Phylogenetic relationships in the Mesostigmata are assessed using DNA sequence data for a segment of the elongation factor-1alpha gene. This is the first application of this nuclear protein coding gene to problems of higher relationships in Parasitiformes. Initial testing revealed extensive variability in nucleotide and corresponding amino acid sequences, both among and within mesostigmatid infraorders. However, accuracy, as assessed by the ability of these data to recover well-supported taxa, was inconsistent for all analyses using unweighted data. None of these analyses consistently recovered Mesostigmata, although less inclusive taxa, such as Uropodina and Trigynaspida, were often recovered. Accuracy was highest for an analysis using applied weighting on the nucleotide sequence data. The overall results provide support for monophyly of Uropodina, Trigynaspida, and a grouping of Zerconina, Parasitina, and Dermanyssina, and suggest close relationships between Heterozerconina and Sejina.