PHYLOGENETIC RELATIONSHIPS OF SCOTUSSA AND LEIOTETTIX (ORTHOPTERA: ACRIDIDAE).

Abstract- A cladistic analysis of the South American grasshopper generaScotussaandLeiotettixwas performed in order to test the monophyly of these genera.Eurotettix, Chlorusand theDichroplus bergispecies group were included as terminal taxa. The genusAtrachelacriswas used to root the tree. Twenty-nine characters from external morphology, male genitalia and female ovipositor were used in the analysis. In order to test for association between the structural change that occurred in the ovipositor valves ofScotussaand the functional change of the oviposition habits, the data matrix was partitioned and two analyses were performed. Characters from the female ovipositor were excluded from the data set used in the first analysis and another analysis was performed where all the characters were included in the analysis. Information on oviposition habits was then mapped on the cladogram, to determine the transformation for performance. Both analyses yielded only one most parsimonious tree and produced congruent results, confirming the monophyly ofLeiotettixandScotussaand corroborating their close relationship. Characters from the female ovipositor valves were informative not only at the species level but also at higher levels in the cladogram. The results also support the hypothesis of association between the structural change that occurred in the ovipositor valves ofScotussawith the functional change in the oviposition habits. However, this association did not seem to be correlated with the adaptive radiation in the genus.