Taxonomy and morphological characterization of Allotettix simoni (Bolívar, 1890) and implications for the systematics of Metrodorinae (Orthoptera: Tetrigidae)

Abstract

Characters used to diagnose the subfamily Metrodorinae (Bolívar, 1887) (Orthoptera: Tetrigidae) are largely variable or homoplastic. Relevant traits used to distinguish amongst subfamilies of Tetrigidae, including sensorial structures, mouth parts, and genitalia are not present in any description of representatives of the subfamily Metrodorinae. The identity of Metrodorinae remains thus at stake. Aiming to fill the current lack of knowledge, a complete anatomical description of adult and last instar nymphs of Allotettix simoni (Bolívar, 1890) is provided. Allotettix simoni is a controverted taxon, originally described in the genus Paratettix and subsequently synonymized with Allotettix peruvianus. The revision of type specimens revealed that A. simoni and A. peruvianus are different species. As neither keys nor descriptions of nymphs of Neotropical Tetrigidae exist, A. simoni nymphs were identified comparing mitochondrial sequences of the cytochrome c oxidase subunit I (COI) gene with adult specimens. The anatomical description of A. simoni expanded by comparisons with material of Metrodora sp. nov., revealed that the subfamilies Metrodorinae and Tetriginae are morphologically very similar, whereas molecular analyses of the COI data set do not support the monophyly of the subfamily Metrodorinae with respect to Tetriginae. Consequently Metrodorinae might not represent an independent entity with respect to Tetriginae.