Insights into the evolutionary history of the neotropical Romaleinae (Acridoidea, Orthoptera)

SONG, H.; POCCO, M.E.; CONFALONIERI, V.A.; CIGLIANO M.M.; GUZMÁN, N.V.

Denver

Congreso; Entomology 2017, ESA's 65th Annual Meeting; 2017

Entomological Society of America (ESA)

The subfamiliy Romaleinae (Romaleidae), with more than 250 valid species in 69 genera, occurs in the Americas, mainly in the Neotropical Region. Its distributional range covers a wide variety of habitats, extending from Argentina and diminishing the diversity to the South of the Nearctic region. One of the hypotheses on the diversification of the group suggests a tropical South American origin, and considers that the colonization of the temperate zones of South America might have occurred earlier than the extension to the temperate zones of North America (Carbonell, 1986). Here we test this hypothesis for the tribe Romaleini sensu lato based on a phylogeny established on morphological and molecular evidences. The total evidence data set included 35 species (47 specimens) representing 19 genera of Romaleini sensu lato, and six outgroup species (6 specimens) of Romaleinae (Phaeopariini, Hisychiini), Ommexechidae and Tristiridae. The morphological set was constituted by 92 characters from external morphology and male genitalia, and the molecular set included fragments of COI, COII and H3 markers. We performed a Bayesian Analysis (BEAST v1.8.3), and the tree obtained was analyzed using the package ?BioGeoBEARS? (Matzke, 2013) in R to estimate the ancestral geographic range of the group. We defined six areas following the regionalization of the Neotropical region by Morrone (2014). The results of the phylogenetic analysis (Fig. 1) recovered with low support all the genera of Romaleini sensu lato considered in this study, except for the genus Antandrus, endemic to Chile, and the South American genus Diponthus. Besides, the representatives of Hisychiini were included in this major clade, grouped with the North American members of the Romaleini. The BAYAREALIKE + J resulted to be the most probable model in BioGeoBEARS, inferring that the ancestral area for the clade of Romaleini, including the members of Hisychiini, was set in the Chacoan and Brazilian subregions (Fig. 1), and the major diversification of the group might have occurred in this area too. Our results suggest a colonization route from South America to North America for this group of grasshoppers. However, this is a preliminary study and we have uncertainty regarding some relationships, e.g., the position of the Hisychiini within the Romaleini clade. Further studies including a wider taxon and character sampling will be conducted in order to obtain a more robust phylogenetic hypothesis for the Romaleinae and to test the biogeographic hypothesis for the whole subfamily.