Cylindrinotina, Espanol, 1956

Ntatsopoulos, Konstantinos, Nabozhenko, Maxim V, Jelinscaia Lagou, Loudmila, Chigray, Ivan A, Gagarina, Ludmila V, Alpagut Keskin, Nurşen, Keskin, Bekir & Papadopoulou, Anna, 2023, Beetles and lichens: tracing the origins and evolution of lichenophagy within the darkling beetle tribe Helopini (Coleoptera: Tenebrionidae), Zoological Journal of the Linnean Society 201 (3), pp. 1-8 : 1-8

Subtribe Cylindrinotina

In contrast to the well-supported clades recovered within Helopina , our phylogenetic reconstruction failed to provide enough resolution within Cylindrinotina , where many clades were poorly supported in both ML and BI analyses ( Fig. 1 ; Supporting Information, Figs S2 , S3). At the same time, our results seem to be inconsistent with data from morphological studies, failing to support the division of taxa of the subtribe into the ‘nalassoid’ and ‘cylindrinotoid’ groups, currently recognized based on larval morphology and on the structure of male and female terminalia ( Nabozhenko 2006a, Purchart and Nabozhenko 2012). In fact, the most species-rich genera of these groups, Nalassus and Odocnemis , respectively, were both recovered as highly polyphyletic in the present work, highlighting the need for a substantial taxonomic revision of Cylindrinotina , once the phylogenetic relationships within this clade are fully resolved.

Ŋe phylogenetic uncertainty regarding the basal relationships within Cylindrinotina recovered in the present study is puzzling, considering our dense taxon sampling and the inclusion of two mitochondrial markers and three separately evolving nuclear protein-coding markers in our dataset. Interestingly, both mitochondrial and nuclear gene fragments targeted in this study provided much stronger resolution within Helopina than within Cylindrinotina (Supporting Information, Figs S7, S8), despite similar levels of informative sites (Supporting Information, Table S4) and of third codon position saturation in both groups (Supporting Information, Fig. S1 ). One possible explanation, which is largely corroborated by our molecular dating analysis, is the relatively rapid diversification of many Cylindrinotina lineages during the beginning of the Palaeogene, which might have been mediated by a steep increase in macrolichen richness occurring during that period (Nelsen et al. 2020b). Multiple closely spaced speciation events can result in ubiquitous discordance between gene and species trees aưributable to incomplete lineage sorting ( Avise et al. 1983, Maddison 1997), in which case concatenation-based tree inference methods of unlinked loci could result in inaccurate estimation of phylogenetic relationships ( Kubatko and Degnan 2007, Roch and Steel 2015). Ŋus, the utilization of coalescence-based tree inference methods might be crucial in resolving the phylogenetic relationships within Cylindrinotina , suggesting that the use of a substantially higher number of unlinked loci (i.e. a genomic dataset) and a denser taxon sampling at both inter- and intraspecific levels should be the main focus of future studies.

Figures

Figure 1. Maximum likelihood phylogenetic tree reconstruction based on the concatenated dataset.Branch colours indicate subtribal groupings (yellow, Enoplopodina; red, Cylindrinotina; and blue, Helopina). Circles in nodes represent values of bootstrap support (BT), posterior probabilities (PP), gene concordance factors (gCF), and site concordance factors (sCF) as indicated in the key.Clades not recovered in the BI analysis are depicted with white PP. Beetle illustrations correspond to terminal taxa as indicated by the leưering in brackets.

Figure 2. Results of the ancestral state estimation analysis. Terminal taxa are colour-coded according to their state as illustrated in the key. Pie charts demonstrate the probability of the ancestral state at each node. In order to provide a time frame for the emergence of different ancestral modes, a time axis is also provided (based on the BEAST run calibrated by known substitution rates).A, evolution of feeding modes under the ER model. B, evolution of habitat preferences under the SYM model within the tribe Helopini.