Review of Hypothyce mixta Howden 1968 (Coleoptera: Scarabaeidae: Melolonthinae)



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Hypothyce mixta is a species of scarab beetle endemic to sandy soils in east Texas. Female H. mixta are not known to fly raising the question of possible cryptic speciation due to lack of gene flow among geographically separated populations. The hypothesis presented in this thesis is that H. mixta is a taxonomically unrecognized, cryptic species complex in which highly endemic populations have undergone sufficient genetic divergence over time to justify their recognition as separate species. The basis for this hypothesis was rooted in unpublished work on the mitochondrial CO1 gene that showed reciprocal monophyly among geographically distinct populations. To test this hypothesis I used mitochondrial and nuclear gene sequences in phylogenetic analysis. A phylogenetic analysis of the nuclear gene 28S showed there is enough gene flow occurring between populations to maintain the singular species representation of Hypothyce mixta but a phylogenetic analysis of the CO1 gene could not be replicated.. However, there are distinct minor morphological differences between populations suggesting that this gene flow may be limited and that populations are diverging.



Biology, Ecology