Andrena Fabricius, 1775

Wood, Thomas J., Ghisbain, Guillaume, Michez, Denis & Praz, Christophe J., 2021, Revisions to the faunas of Andrena of the Iberian Peninsula and Morocco with the descriptions of four new species (Hymenoptera: Andrenidae), European Journal of Taxonomy 758, pp. 147-193 : 151

Genus Andrena Fabricius, 1775

Molecular analyses

In the phylogenetic relationships among species of Taeniandrena ( Fig. 1 ), all species represented by more than one individual formed well-supported monophyletic groups, with the exception of A. wilkella (Kirby, 1802) , for which support was low (posterior probability, hereafter PP, of 0.74). These analyses confirm the distinctiveness of A. beaumonti Benoist, 1961 stat. rev. and A. wilkella , which form two separate clades with A. benoisti Wood & Praz sp. nov. sister to A. wilkella and A. beaumonti sister to A. benoisti + A. wilkella . The distinctiveness of A. gelriae s. tr. and A. gredana stat. nov. is also supported; these taxa do not form a monophyletic group. The sampled specimens of A. ovatula (Kirby, 1802) were similar to specimens of A. ovatula s. str. from northern Europe, a taxon that we consider distinct from most populations of ‘ A. ovatula auct.’ from central and southern Europe (Praz & Wood, in prep.). Lastly, A. levante Wood & Praz sp. nov. was the sister species to A. gelriae s. str. (PP less than 0.5).

Average within-species, uncorrected genetic distances were low for A. ovatula , A. gredana , A. levante sp. nov. and A. benoisti sp. nov. (0.022%, 0.66%, 0.0% and 0.43%, respectively) and considerably higher for A. wilkella (1.18%) and A. similis Smith, 1849 (1.17%). Uncorrected genetic distances between A. benoisti sp. nov. and A. wilkella were on average 3.30% (range 2.86–3.86%), those between A. benoisti sp. nov. and A. beaumonti stat. rev. 7.31% (range 7.13–7.61); Andrena beaumonti was on average 6.89% divergent from A. wilkella (range 6.62–7.26%). Distances between A. gredana and A. gelriae were on average 3.02% (range 2.98–3.07), those between A. levante sp. nov. and A. gelriae 1.67% (range 1.51–1.75).

The analyses of the Ptilandrena-Euandrena ( Fig. 2 ) clade strongly support the recognition of A. impressa stat. nov. as a distinct species and not as a subspecies of A. angustior ; these taxa were not closely related in our trees ( Fig. 2 ). The placement of A. impressa (sister to a clade composed of A. fulvata Stoeckhert, 1930 , A. angustior , A. allosa Warncke, 1975 and A. amieti Praz, Müller & Genoud, 2019 ) was surprising given that A. impressa shares numerous morphological features with A. fulvata and A. angustior , in particular the broadened gena and long male mandible, this character being absent in A. allosa and A. amieti , displaying the ‘typical’ unbroadened gena found in Euandrena . Support for this arrangement was however very weak. Average genetic distances within A. angustior and A. fulvata were 0.20% and 0.38%; distances between these two taxa were on average 3.56% (range 3.10–4.15). The distances between the single specimen of A. impressa and these two taxa were considerably higher: on average 8.22% for distances with A. fulvata (range 8.08–8.40) and 8.61% with A. angustior (range 8.39–9.22). With the exception of the difference between A. gelriae and A. levante sp. nov., these between species genetic distances are well above the 2% divergence metric that typically indicates species-level differences ( Schmidt et al. 2015).

Figures

Fig. 1. Molecular phylogeny of the subgenus Taeniandrena Hedicke, 1933 with a focus on West Mediterranean species. Maximum clade credibility tree found in Bayesian analyses of sequence data of the mitochondrial gene COI; numbers above branches indicate posterior probabilities; values below 0.5 are omitted.

Fig. 2. Molecular phylogeny of the Andrena angustior (Kirby, 1802) group within the broader Ptilandrena-Euandrena group. Maximum clade credibility tree found in Bayesian analyses of sequence data of the mitochondrial gene COI; numbers above branches indicate posterior probabilities; values below 0.5 are omitted.