Acanthonevrini (Phytalmiinae)

Korneyev, Severyn V., Hancock, David L., Hauser, Martin, Korneyev, Valery A. & Gaimari, Stephen D., 2021, A new species of the genus Themarictera Hendel (Diptera: Tephritidae: Phytalmiinae: Acanthonevrini) from Madagascar, Zootaxa 4996 (2), pp. 383-391 : 384-385

Tribe Acanthonevrini (Phytalmiinae)

Formally established and diagnosed by Hering (1941; 1947), this tribe was defined by V. Korneyev (1994) as a monophyletic lineage supported by a single, but unique synapomorphy: the medioapical lobes of the oviscape (sclerotized “capes” dorsally and ventrally between the bases of the taeniae) having a W-shaped appearance and being medially desclerotized.

Acanthonevrini are restricted to the Old World, occurring mostly in the Oriental and Australasian Regions, and to a lesser degree in the Afrotropical Region and the southeastern part of the Palaearctic Region (Far East Russia, China, Korea, and Japan). Australasian species largely were revised by Hardy (1986) and Permkam & Hancock (1995), while numerous authors have discussed the Oriental fauna on a regional basis.

Relationships among the genera of Acanthonevrini were provisionally considered by V. Korneyev (1999) and, in comprehensive keys to genera and species included in the Acanthonevra , Sophira , Rioxa , Dacopsis , Aethiothemara , Diarrhegma , Dirioxa and Themaroides complexes by Hancock (2011, 2012, 2014a, 2014b, 2015).

The Acanthonevrini are thought to be one of the most basal lineages of the family Tephritidae , comprising primarily species with saprophagous larvae ( Korneyev, 1994). Such a mode of larval feeding is known in most Phytalmiinae and some Gastrozonini (Dacinae) ( Dohm et al. 2014, Copeland 2007). Many species from the Oriental Region (e.g., Ptilona Wulp and the Sophira complex of genera) are associated with bamboos but the larvae of most (including Acanthonevra Macquart , Themara Walker , Erectovena Ito and Lenitovena Ito ) live under the bark of trees or in decaying logs, similar to those of many Ulidiidae , Pallopteridae and Lonchaeidae , which apparently represents the initial mode of feeding of the Tephritoidea as a whole.

The Afrotropical acanthonevrines are represented by about three dozen species belonging to six genera of unclear relationships, all included by Hancock (2015) in the Aethiothemara group: Afrocneros Bezzi, 1924 (3 species), Labeschatia Munro, 1967 (1 species), Ocnerioxa Speiser, 1915 (11 species), Ptiloniola Hendel, 1914 (3 species), Aethiothemara Hendel, 1914 (6 species) and Themarictera Hendel, 1914 (1 previously known species). Keys to Afrotropical genera and species were provided by Munro (1967) and Hancock (1986, 2015).

Hancock (2015) defined this group by the presence of 1 long and several shorter mid-tibial apical spines, lack of anepimeral setae, and the r-m crossvein being located at the apical third of cell dm, with all of these characters being homoplasious within the tribe, leaving a possibility that the Afrotropical species can be either a monophyletic or polyphyletic group of two monophyletic lineages:

1) Afrocneros , Labeschatia , Ocnerioxa and Ptiloniola have 2 pairs of scutellar setae (synapomorphy), vein R 1 ending at r-m level and pterostigma less than 1.5× as long as the costal cell (symplesiomorphy);

2) Aethiothemara and Themarictera have 3 pairs of scutellar setae (symplesiomorphy), vein R 1 ending at dm-m level and pterostigma very long and wide, more than 1.5× as long as the costal cell (synapomorphy).