Phylogeny of the Rove Beetle Genus Bledius (Coleoptera: Staphylinidae)

The genus Bledius is a diverse group belonging to the subfamily Oxytelinae in the family Staphylinidae with over 439 species found globally apart from many oceanic islands and Antarctica. Bledius is known using their mandibles known for the construction of burrows that serve as their habitat. Species within this genus exhibit considerable variability in habitat preference. They inhabit banks of different water bodies with some species found in both freshwater and saline environments and can be found in many different vegetation including lightly or densely vegetated soil and clay beds. Despite the differences in habitat preference, all species need algae and moist conditions to survive. Over the years, the classification of Bledius was disorganized. Based on previous classifications by LeConte and Schiödte, Herman (1986) divided the genus into 34 species groups. In this study, 58 Bledius and 5 outgroup species are analyzed with 14 species groups identified. Only 10 species groups are tested for monophyly as 4 of the species groups (kosempoensis, angustus, emarginatus and furcatus) are represented by a single species. Fourteen nuclear protein-coding genes were targeted and amplified with multiplex PCR. Sequencing was carried out with the Oxford Nanopore Technologies (ONT) MinION platform and subsequently inferred using Maximum Likelihood. Due to compatibility error and likely expired library kit, the dataset was heavily reduced. The ML tree showed high support for most of the nodes, with only few showing moderate to low support. Only four species groups: verres, basalis, mandibularis and armatus were identified as monophyletic while punctatissimus, gigantulus, kochi, semiferrugineus, annularis and albonotatus species groups were recovered as non-monophyletic. The relationship within gigantulus and kochi species groups were inconsistent with Herman’s (1986) hypothesis, while those in annularis and albonotatus species groups were partially in agreement. The evolutionary relationship between and within species groups are not fully consistent with previous morphology-based hypotheses. Mapping morphological characters onto the ML tree revealed numerous homoplasious characters with only a few characters state showing unique patterns within the species groups. While some of the characters supported the grouping of certain species groups, the tarsal formula and features of the male genitalia suggest alternative groupings. Many of the characters (and homoplasious characters), requires further investigation.