Lepanomini, Wanat, 2021

Wanat, Marek, 2021, New basal taxa of South African Apioninae (Coleoptera: Curculionoidea: Brentidae), Zootaxa 5035 (1), pp. 1-60 : 57

Lepanomini trib. n.

Type genus: Lepanomus Balfour-Browne, 1945

Genus included: Lepanomidius n. gen.

Diagnosis. Body with simple erect setae ( Lepanomidius ) or vestiture dual: truncate erect setae + appressed setae ( Lepanomus ). Temples and genae punctate, not transversely wrinkled. Antennal scrobes sulciform, latero-ventral. Antennae inserted on rostrum in its basal third, distinctly longer than half length of elytra; scape shorter than 2 proximal segments of funicle combined; three most distal funicular segments barely elongate or transverse; antennal club long and loose. Pronotal disc punctate. Subhumeral portion of elytral stria 10 absent, apically striae joining in a formula (1+10)+(2+9). Front legs not enlarged. Procoxal cavities contiguous. Procoxae prominent, anteriorly without transverse subapical rim. Mesocoxae narrowly separated (less than 0.15 width of coxa). Dentiform process of pro- and mesocoxae low and obtuse. Trochanters shortly elongate (less than 1.5 × as long as wide). Femora unarmed. Tibiae lacking sharp edges, with long erect setae on outer side. Tarsi unmodified; protarsomere 1 subtruncate or emarginate.

Male: mucrones present on mid and hind tibiae; membrane of tergite VII without median pocket-like invagination; pygidium lacking tongue-like internal process, with long anterior apodemes; sternite VIII carinate, with welldeveloped lobes; membrane between sternites VIII and IX without additional sclerites; typical endophallic frena absent, additional sclerites present.

All the above tribes represent an ancient fauna of Apioninae , currently restricted in its distribution to the southern hemisphere. Poorly diverse taxonomically, the tribes often comprise single genera that are markedly divergent morphologically. They well conform to the overall idea of the Apionidae phylogeny presented by Wanat (2001), although with a limited taxon sampling. In the phylogenetic trees obtained for Brentidae sensu lato, all the subgroups of derived apionines were resolved in the clade Apionitae + Aspidapiitae, later merged by Bouchard et al. (2011) and Alonso-Zarazaga & Wanat (2014). The latter decision was subsequently corroborated in molecular phylogenetic analyses performed by Winter et al. (2017). Contrary to the morphologically well-defined supertribe Apionitae in the current sense, supported by non-homoplastic synapomorphies like the pocket-like lock of the elytral suture at the apex or the wrinkled and thin-walled spermatheca, all the remaining apionid lineages studied by Wanat (2001) are much weaker and more ambiguously supported by homoplasies. They largely form a grade on the phylogenetic tree, particularly in its basal region. Therefore, they were given the same taxonomic rank as the current Apionitae , to comply with the rules of cladistic classification. This resulted in a division of Apioninae of the current rank into 6 more supertribes (subfamilies in Wanat, 2001). That major division of the Apioninae was clearly considered temporary in 2001, knowing that some relevant basal genera could not be sufficiently studied, and others remained then undescribed.

The three new genera described herein together with Lepanomus Balf. -Br., require tribes of their own, based on remarkable morphological differences. This decision increases the problem of imbalance in the Apioninae supertribal classification. Considering the mosaic distribution of many relevant characters between newly added ‘primitive tribes’, as well as the previously unstudied genera Afrotibicina and Setapion , it becomes evident that newly described genera and tribes cannot be simply incorporated into the existing supertribes. It concerns both the African basal taxa, and some other genera from remaining Austral Gondwanan refuges, like the New Zealand Zelapterus Kuschel , Strobilobius Kuschel and Cecidophyus Kuschel , and South American Noterapion Kissinger and Chilapion Kissinger. They represent relict apionine clades and cannot be simply assigned either to Rhadinocybitae or Apionitae , because of remarkable sets of plesiotypic morphological characters, and lack of autapomorphies of these two supertribes. One more such problematic relictual genus yet to be described occurs in Madagascar, and another one in Tasmania (Wanat, unpublished obs.). In the current stage of knowledge, the most reasonable solution concerning the higher classification of the Apioninae seems to abandon the provisional supertribal division proposed by Wanat (2001), at least until a comprehensive combined morphological and molecular phylogeny of the Apioninae has been carried out. An example of a similar approach was recently given by Alonso-Zarazaga et al (2017) in the catalogue of the Palaearctic Curculionoidea , and I follow this approach in the present study.