Review of competing hypotheses of phylogenetic relationships of Paussinae (Coleoptera: Carabidae) based on larval characters

Larval structural characters are an important component in phylogenetic reconstruction of the subfamily Paussinae. Based on larval characters, two main cladistic hypotheses have been proposed concerning basal relationships within Paussinae: (1) Metriini as sister-group of Ozaenini + Paussini, with Ozaenini as a paraphyletic group and the genus Physea as sister-group of Paussini; and (2) Metriini as sister-group only of the monophyletic Ozaenini, with the Paussini as sister-group of Metriini + Ozaenini. We present here a review of these hypotheses and a new cladistic analysis based on larvae, emphasizing the phylogeny of Ozaenini. The analysis includes the following taxa: Metrius (Metriini), Itamus, Pachyteles, Sphaerostylus, Physea (Ozaenini), Platyrhopalopsis and Paussus (Paussini). For both Physea and Platyropalopsis larvae we provide new detailed descriptions, because previous descriptions are inadequate to allow an advanced phylogenetic discussion. A total of fifty-six characters are analysed. Most characters show alternative states organized into sequences of character states, each of which is logically derivable from its neighbour in the sequence, resulting in an almost completely pectinate cladogram. Metrius is the sister-group of all other Paussinae, and Paussini are a highly derived offshoot within the ozaenine grade. According to the present analysis, Physea, regarded traditionally as a typical ozaenine, represents the ozeanine sister to Paussini, showing that Ozaenini are paraphyletic. As our analysis is based on the few paussine genera sufficiently known at the larval stage, which represent a low number of the extant paussine genera, the results are merely illustrative of the evolution of the major clades within the subfamily. More detailed information about the phylogeny of ozaenines could arise from a more comprehensive analysis, mainly including adult morphological characters.