Reassessment of the Saicini phylogeny and evolution of hairy attachment structures on tarsi (Heteroptera: Reduviidae: Emesinae)

Abstract

Saicini comprise 24 genera and 147 species worldwide. Here, we include additional taxa and characters to the morphological dataset of CastroHuertas and Melo (2023) into a new one composed of 181 characters, which was analysed cladistically with 63 terminals, comprising 18genera (75% of the generic diversity), 49 species of Saicini, and 12 outgroups. Saicini was recovered as monophyletic, with Carayonia orientalis (Visayanocorini) as its sister-species. Our hypotheses recovered two main clades within Saicini that we recognized as two new subtribes: Saicina subtrib. nov. and Tagalina subtrib. nov.; and the new tribe, Saiciretini trib. nov. of uncertain affinities within Emesinae. Additionally, the morphology and evolution of the scopula is explored. The scopula is a hairy attachment structure on the third tarsomere composed of a set of spatulatesetae present on all legs of Saicini and on the meso- and metalegs of a few species of the tribes Emesini and Leistarchini (Emesinae). Scopula presence on all legs had been recovered as synapomorphy of the tribe Saicini. The reconstruction of the ancestral state of the hairy setae shows an emergence of this structure on the ventral region of the third tarsal segment of the protarsus in Saicini and its ancestor without scopula. The arrangement of the scopula is consistent with the recovered clades.