Dispersal versus vicariance in the Aegean: combining molecular and morphological phylogenies of eastern MediterraneanDendarus(Coleoptera: Tenebrionidae) sheds new light on the phylogeography of the Aegean area

Abstract

The Aegean archipelago, as an ‘evolutionary laboratory of nature’, is an ideal model for research in phylogeography. In this area, the darkling beetles of the genus Dendarus (distributed from Morocco to the Caucasus) exhibit a high level of diversity with 36 species, 27 of which are island endemics. However, their taxonomy is complex and unstable, having undergone continuous revision to address extensive morphological and ecological plasticity. Here, we examine the phylogenetic relationships of 23 species from Greece and Turkey, using mitochondrial and nuclear DNA sequences and 61 morphological characters, to unveil their phylogeny in the Aegean. This helps to clarify phylogeographic scenarios and historical processes that shaped the observed patterns. The analyses reveal 13 distinct lineages with several para- and polyphyletic cases that correspond to three major phylogroups [south/south-east Aegean (D. foraminosus complex, D. rhodius, D. sporadicus, D. wettsteini); central to north Aegean, Turkey and mainland Greece (D. crenulatus, D. moesiacus group, D. sinuatus complex, D. stygius) and mainland Greece (D. messenius, D. paganettii)], indicating the need for further taxonomic re-evaluation. Lineage topology and phylogeography suggest a spatial and temporal sequence of geographic isolation, following either a vicariant or a dispersal model coincident with major palaeogeographic separations in the Aegean.

On the type species of the genus Dendarus Dejean, 1821 (Coleoptera: Tenebrionidae)

“…As Dejean (1821) did not fix the type species, the two available species-group names are originally included nominal species that can be selected for subsequent designation (see Arts 67.2.1, 69.1 of ICZN 1999). Mulsant (1854b) transferred Blaps emarginata to the genus Heliopates Dejean, 1834, where it remains to this day (Español & Viñolas 1983, 1987a, b, 1990, Trichas et al 2020. Therefore, taking into consideration the regulations of the ICZN (1999), and the widely accepted taxonomic distinctiveness of Dendarus and Heliopates (e.g., Español & Viñolas 1983, 1987, Kamiński et al 2019, at this point only Helops tristis Rossi can be considered as a potential type species of the genus Dendarus.…”

“…Dendarus Dejean, 1821 (Coleoptera: Tenebrionidae) is a well-known genus of flightless darkling beetles inhabiting the Western Palearctic Region (Trichas et al 2020). The genus is represented by 89 species and subspecies classified in six subgenera (Iwan et al 2020, Bouchard et al 2021, and is currently placed within the tribe Dendarini Mulsant & Rey, 1854 of the subfamily Blaptinae Leach, 1815 (Kamiński et al 2020).…”

Geology‐based and ecological processes of divergence between and within species of wingless darkling beetles

“…Biogeographical analyses favour the hypothesis invoking a dual role of vicariance and dispersal driving the biogeography of Misolampus since the early Miocene (Figure 4; Appendix S3, Figure S3.2). Interestingly, there is mixed evidence for each biogeographical scenario in previous works on beetle historical biogeography (Condamine et al, 2013; García‐Vázquez et al, 2017; Mas‐Peinado et al, 2018; Micó et al, 2009; Riccieri et al, 2017; Ruiz et al, 2012; Trichas et al, 2020; Trizzino et al, 2011). Our results reveal an ancient vicariance between the proto‐Iberian Peninsula and North Africa that has led to an old divergence within the Western Mediterranean region of two isolated lineages.…”

“…Palaeoclimatic projections display a general pattern of expansion of environmentally favourable areas during the LGM and suggest range contractions during the LIG and mid‐Holocene. This scenario implies a different temporal perspective in analyses of diversification in Tenebrionidae (Condamine et al, 2013; Mas‐Peinado et al, 2018; Trichas et al, 2020), which considers the possible role of glaciations in driving incipient speciation. Under this perspective, allopatric isolation may be followed by adaptation to new environmental conditions in relatively short periods of time, counteracting phylogenetic conservatism, which tends to counter ecological niche divergence (Pyron et al, 2015).…”

Spatial Phylogenetics, Biogeographical Patterns and Conservation Implications of the Endemic Flora of Crete (Aegean, Greece) under Climate Change Scenarios

“…SIE paleo-endemics, which are remnants of an older continental flora [ 105 , 112 , 113 ], likely persisted in mid- and higher-altitudes ( Figure 2 A and Figure 3 A; Table S1 ) and at least some of them became high-elevation specialists [ 105 ]. Thus, historical processes, such as mountain uplift and isolation due to sea-level oscillations, seem to have driven diversification and endemic species distribution in Crete (e.g., [ 114 ]), with this pattern being evident in Cretan endemic animals as well (e.g., [ 115 ]) and in other regions of the world [ 24 , 107 , 116 , 117 , 118 ].…”