Untangling the evolution of soldier beetles (Coleoptera: Cantharidae) and the evaluation of the morphological phylogenetic signal in a soft‐bodied elateroid lineage

Abstract

This study addresses the long‐standing uncertainty about the internal classification of soldier beetles (Elateroidea: Cantharidae). Four datasets were compiled and analysed: 66 genes for 14 terminals, 15 mtDNA genes for 79 terminals, one mtDNA and two rRNA genes for 217 terminals, and barcodes for 576 terminals. Based on congruent topologies, Chauliognathinae is proposed as a sister to the remaining Cantharidae, followed by the redefined Malthininae (including Tytthonyxini), the paraphyletic “dysmorphocerine” lineages (Dysmorphocerinae sensu stricto and Heteromastiginae subfam. nov.), and Silinae + Cantharinae as a terminal clade. The present phylogeny supersedes earlier morphology and short‐fragment molecular hypotheses that have not converged on a consensus. Few morphological characters corroborate the DNA‐based relationships (see the adults and larval keys). However, morphology‐based hypotheses have relied on a few informative characters, and no evidence strongly rejects the preferred molecular topology. The interpretation of morphological characters and uncertain polarity resulting from the high phenotypic disparity of Elateroidea are discussed in detail. The dated phylogeny hypothesizes the earliest split within the Cantharidae in the Berriasian stage (Early Cretaceous, ~141 Myr) and the diversification of most extant subfamilies and tribes already in the Late Cretaceous. The most diverse subfamily, Cantharinae, represents a delayed radiation that started during the Eocene climatic optimum, 55.5 Myr. The late origin of Cantharinae questions the classification of Cretaceous Cantharidae as members of Cantharinae. Instead, the results suggest their deeper rooting after separating from dysmorphocerine lineages and before the node between Cantharinae and Silinae.

On the nomenclatural status of type genera in Coleoptera (Insecta)

“…Family-group name: HETEROMASTIGINAE Motyka, Biffi & Bocák in Motyka et al, 2023b : 559. Stem: Heteromastig -.…”

New species of Malthodes Kiesenwetter, 1852 (Coleoptera: Cantharidae) from the Greater Caucasus, with notes on distribution of the genus in the area

“…The drawback of the act, however, is that at least some old synonyms of Malthodes apparently had not been taken into consideration, so there is a chance that the suggested new subgenera may fall into synonymy after a revision of the genus is carried out on a larger scale, on the material from all parts of its distribution areas, and with inclusion of at least type species of the synonymised subgenera/genera in the analysis. Besides, as the Malthininae, where the tribe Malthodini with the genus Malthodes belongs, appeared to be one of the basic cantharid lineages, molecular dating placing the node back at ca 100-90 Myr [Motyka et al, 2023], a reference to the accessible molecular data to defi ne the relationships between its variable members might also be helpful.…”

Rediscovery of <i>Malthesis ater</i> Motschulsky, 1853 and a catalog of the genus <i>Malthesis</i> Motschulsky, 1853 (Coleoptera, Cantharidae)

“…In the current classification (Magis and Wittmer 1974, Brancucci 1980, Motyka et al 2023, two lineages of genera are recognized in Chauliognathini. In the first, the elytra are extremely reduced, covering up to two abdominal tergites and exposing most of the hind wings, e.g., Maronius Gorham, 1881, Paramaronius Wittmer, 1963, Lobetus Kiesenwetter, 1852, Macromalthinus Pic, 1919, etc.…”