Mesostenus

Santos, Bernardo F. & Brady, Seán G., 2024, Leveraging museum specimens, genomics and legacy datasets to unravel the phylogeny and biogeography of cryptin wasps (Hymenoptera, Ichneumonidae, Cryptini), Zoologica Scripta 53 (3), pp. 338-357 : 352

4.3.6 | Clade E: Mesostenus group

This was the largest individual genus group recovered in S17, mostly comprised of Old World taxa but also including some widespread genera (e.g. Mesostenus ) and a few speciose Neotropical genera (e.g. Polycyrtus , Cryptanura ). Herein, representatives of seven genera were added to the dataset. Some relationships for the newly included genera were particularly congruent with biogeography. The Malagasy genus Afretha was recovered as sister to the sympatric Mesophragis . Buysmania oxymora , which is widespread in the Oriental region, was nested within Euchalinus , an Oriental genus for which the studied specimens came from Indonesia and the Philippines. The two small Neotropical genera Mecistum and Hercana were recovered as sister groups, both belonging to Townes' former subtribe Mesostenina . Tanepomidos assamensis , from India, was recovered nested in a clade that includes other Oriental genera such as Goryphus , Skeatia , Perjiva , Euchalinus and Buysmania . Given the paraphyletic nature of Goryphus , the generic limits within this clade need to be revised to identify monophyletic and diagnosable supra-specific units.

Conversely, the Oriental genus Lipoprion was recovered as sister to the Neotropical Cryptanura . In this case, both genera share distinctive morphological traits such as the transversely elongated areolet and S1 ending at spiracle level, as well as general similarity in the shape of the head and mesosoma.

Contrary to the results of S17, we found Mesostenus as a polyphyletic group. This is not entirely surprising, as in the early taxonomic history of Ichneumonidae this genus used to be a general repository for all species of Cryptini with a small areolet (the species with large areolet being housed in Cryptus ). While Townes' extensive taxonomic revisions (e.g. Townes, 1970; Townes & Townes, 1962, 1966) have greatly contributed to improve the delimitation of these traditional ‘wastebasket genera’, these older and larger groups are often the ones that have been recovered as para- or polyphyletic in large-scale phylogenies.