<p><strong>Phylogenetic methods applied to extinct beetles — the case of †<em>Tunguskagyrus</em> (Gyrinidae or †Triaplidae)</strong></p>

Abstract

†Tunguskagyrus, a Late Permian beetle fossil, was assigned to the adephagan family Gyrinidae in the original description. This placement was challenged in a recent study, where the genus was considered as part of a broad new concept of the extinct family †Triaplidae and transferred from Adephaga to Archostemata. Even though some structural features deviate from the typical pattern found in extant Gyrinidae, we maintain the placement of †Tunguskagyrus in the stemgroup of this family as the most plausibe interpretation. The suggested taxonomic changes concerning †Triaplidae (and †Schizophoroidea) are invalidated by an insufficient phylogenetic approach and several misinterpretations of the fossil imprints. The arguments are based on 1) general habitual similarity, 2) ubiquitous characters, 3) plesiomorphies, or 4) apomorphic conditions (compared to the Coleopteran groundplan) occurring in many beetle groups, strongly affected by homoplasy. The taxonomic shift of †Tunguskagyrus and the new concept of †Schizophoroidea and †Triaplidae are discarded due to the lack of a defined phylogenetic methodology and synapomorphies.