Geometric morphometrics as a tool to understand biogeographical and evolutionary patterns in crane fly genus Ischnotoma Skuse (Diptera, Tipulidae)

Abstract

Background. The geometric morphometric analysis is applied for the first time for the family Tipulidae to distinguish evolutionary and biogeographical patterns on Ischnotoma species from Neotropical and Australian regions. We included 45 recognized species of the genus, representing its three subgenera I. (Icriomastax), I. (Ischnotoma), and I. (Neotipula). This paper aims to test if the three subgenera are recoverable using this set of morphometric data. Methods. Twenty-two landmarks were selected on the wing, mostly located on the radial and medial veins. A Regression Analysis, Principal Components Analysis (PCA), a Shape Coordinates PCA and a Canonical Variate Analysis (CVA) were used to test the variations among individuals, wing shape and groups. Results. For all analyses, the species of Ischnotoma (Neotipula) has a strong dissociation from the remaining species and the CVA shows a complete separation of the three subgenera. This study represents the first insight for a new assessment of Ischnotoma and the first step to giving a possible new status for I. (Neotipula).