Integrative taxonomy solves taxonomic impasses: a case study from Epyrinae (Hymenoptera, Bethylidae)

Abstract

We apply integrative taxonomy to solve a historical taxonomic impasse in a flat wasp group (Hymenoptera, Bethylidae). The phylogeny of Epyrinae is inferred with parsimony analyses under equal and implied weights, maximum likelihood and Bayesian inference using the nuclear markers 18S and 28S, the mitochondrial genes 16S, cytochrome oxidase subunit I and cytochrome B and 232 morphological characters. This is the first phylogenetic study to examine all 42 epyrine genera, including junior synonyms and extinct taxa, applying a combined molecular and morphological approach. This study considered 186 terminal taxa with 166 representing the ingroup taxa and 20 outgroup taxa. All resulting trees of the combined analyses recovered Anisepyris Kieffer, Aspidepyris Evans, Bakeriella Kieffer, Disepyris Kieffer, Laelius Ashmead and Trachepyris Kieffer as monophyletic; Chlorepyris Kieffer, Epyris Westwood, Formosiepyris Terayama and Holepyris Kieffer are nonmonophyletic. Calyozina Enderlein is recovered as an independent lineage in implied weights, Bayesian and maximum likelihood topologies. Here, we describe three new genera and revalidate six genera, five of them junior synonyms of Epyris and one of Holepyris. In addition, we analysed the presence/absence of a sulcus between the mesoscuto-scutellar foveae and the shape of mesoscuto-scutellar foveae as the most important taxonomic characters for Epyrinae using ancestral state reconstruction. Finally, we provide a checklist of all species of Epyrinae, compiled via direct observation of the type, illustrations, or literature and an updated and illustrated taxonomic key for all epyrine genera.

Diversity and phylogeny of the extinct wasp subfamily Lancepyrinae (Hymenoptera, Bethylidae) revealed by mid-Cretaceous Burmese amber

“…Indeed, these morphology-based hypotheses do not fully align with molecular-based hypotheses (Carr et al 2010;de Brito et al 2022;Colombo et al 2022) and many deep relationships remain undeciphered. While a sister-group relationship of Mesitiinae and Scleroderminae has been repeatedly found (Carr et al 2010: using 'Cephalonomiini' in place of Scleroderminae;de Brito et al 2022;Colombo et al 2022), morphological analyses including extinct lineages retrieve the Mesitiinae in different positions [sister-group to all extant Bethylidae but Bethylinae in Colombo et al (2020); sister-group to all extant subfamilies here].…”

“…Indeed, these morphology-based hypotheses do not fully align with molecular-based hypotheses (Carr et al 2010;de Brito et al 2022;Colombo et al 2022) and many deep relationships remain undeciphered. While a sister-group relationship of Mesitiinae and Scleroderminae has been repeatedly found (Carr et al 2010: using 'Cephalonomiini' in place of Scleroderminae;de Brito et al 2022;Colombo et al 2022), morphological analyses including extinct lineages retrieve the Mesitiinae in different positions [sister-group to all extant Bethylidae but Bethylinae in Colombo et al (2020); sister-group to all extant subfamilies here]. Similarly, the Pristocerinae has been found to be sister of the Epyrinae (Carr et al 2010: using 'Epyrini' instead of Epyrinae) or [Epyrinae + Protopristocerinae] (Colombo et al, 2020; this study), but other molecular analyses found it as sister to all extant subfamilies but the Bethylinae (de Brito et al 2022;Colombo et al 2022).…”

“…While a sister-group relationship of Mesitiinae and Scleroderminae has been repeatedly found (Carr et al 2010: using 'Cephalonomiini' in place of Scleroderminae;de Brito et al 2022;Colombo et al 2022), morphological analyses including extinct lineages retrieve the Mesitiinae in different positions [sister-group to all extant Bethylidae but Bethylinae in Colombo et al (2020); sister-group to all extant subfamilies here]. Similarly, the Pristocerinae has been found to be sister of the Epyrinae (Carr et al 2010: using 'Epyrini' instead of Epyrinae) or [Epyrinae + Protopristocerinae] (Colombo et al, 2020; this study), but other molecular analyses found it as sister to all extant subfamilies but the Bethylinae (de Brito et al 2022;Colombo et al 2022). Finally, one major change between our cladogram and those found in the above-mentioned works is the position of the Bethylinae, as the first extant subfamily to diverge in all the contributions while it is here deeply nested within the tree.…”

Revision of the Gondwanan genus Chilepyris Evans, 1964 (Hymenoptera: Bethylidae)

“…Among the five extant subfamilies, the Pristocerinae are the one with the most evident sexual dimorphism, in which the females are apterous, with extremely reduced eyes and without ocelli, while the males are macropterous, with developed eyes and ocelli (Azevedo et al 2016, 2018). On the contrary, in the Epyrinae, the Mesitiinae and the most of Bethylinae, the sexual dimorphism is minimal (see Azevedo et al 2018; Colombo et al 2022), with few cases of evident morphological characteristics, as in epyrine genus Calyoza Hope, in which males have a pectinate antenna and the flagellomere I is extremely reduced, like as a ring‐shaped, whereas females have a filiform antenna and the flagellomere I is the same size as the latter ones (for more details, see Colombo et al 2022), and Bethylus Latreille, which females of several species are polymorphic with apterous, brachypterous and macropterous forms (Richards 1939).…”

The first flat wasps (Hymenoptera: Bethylidae) from Miocene Mexican amber

“…Following the key to the subfamilies of Bethylidae of Azevedo et al (2018), this specimen keys in the Epyrinae for the fully-developed wings, without Rs+M, the metanotum short, the metapectal-propodeal complex without posterior spines, the metasomal segment 2 regularly long, the mesopleuron with transepisternal line, the fore wing with anterior margin straight and C present. Following the key to the genera of Epyrinae of Colombo et al (2022b), it keys between Epyris Kieffer, 1914 and Bakeriella Kieffer, 1910 for the mesoscuto-mesoscutellar foveae not connected by sulcus, the posterior ocelli broadly separated, the dorsal pronotal area without elevation anteriorly and the anterior margin not incurved, the anterior area of sternite 2 without flap and the antennae not pectinate, the mesoscuto-mesoscutellar foveae separated by less than half their own length, the metapectalpropodeal disc with distinct metapostnotal-propodeal carina. However, some features merely indicate Bakeriella for the present fossil: the body with metallic reflections, as is visible in some Bakeriella but not in Epyris (Azevedo et al, 2018); the mesoscuto-mesoscutellar foveae subelliptical rather than rectangular, a pattern of Bakeriella (e.g., Azevedo, 2014: figs.…”