Aspistomella, Hendel, 1909

Aspistomella View in CoL group of genera

Within the tribe, the genera Aspistomella , Polyteloptera , and Ulivellia form a group here called the Aspistomella group, which differs from other genera of Lipsanini by the combination of a head with a moderately or very large epistome (lower part of the face), strongly anteroventrally produced and conspicuously (usually 2×) higher than the low clypeus (synapomorphy) almost hidden in the peristomal cavity (synapomorphy).

The Aspistomella group of genera belongs to a broader monophyletic lineage (here called the Amethysa lineage) together with the taxa sharing frontal setulae modified to form long and strong frontal and interfrontal setae (synapomorphy); row of fine and short parafrontal setulae 3–5× shorter than frontal setae (synapomorphy); very long ocellar seta (usually 2× or more as long as the postpedicel); very long inner vertical seta (slightly longer than the ocellar seta); short outer vertical seta (at most half as long as inner vertical seta or vestigial) (apomorphies), often setulose vein R 1 (plesiomorphy; secondarily bare in some species); unmodified, relatively short aculeus with tergosternite 8 moderately wide and oval in section (plesiomorphy) and cercal unit oval, not flattened and bearing long setulae (plesiomorphy) (Kameneva & Korneyev, in press).

Other taxa of the Amethysa lineage are distinguished by the low, less produced epistome combined with a high clypeus almost as high as the epistome (except those either without epistome of a receding face ( Eumetopiella , Stenomyia ) or, if the epistome is antero-ventrally produced ( Steneretma , Zacompsia ), then with a high clypeus (Kameneva & Korneyev, in press).

The genera of Lipsanini , except those of the Amethysa lineage, are easily distinguished by the uniformly short, undifferentiated (plesiomorphy), subequal inner and outer vertical setae (plesiomorphy).Among them, many species assigned to Acrosticta , Acrostictomyia , Axiologina , Euxesta , and Pareuxesta share a very narrow and long aculeus, 1.5× longer than the oviscape (synapomorphy), and apparently form another monophyletic lineage (Kameneva & Korneyev, in press).

The species assigned here to the genera of the Aspistomella group often have dorsoapically setulose vein R 1 (possible plesiomorphy, occurring occasionally in different lineages of Lipsanini and Pterocallini, but very common in the Otitini and Myennidini , black halteres (possible apomorphy, not found in most other Ulidiidae ), and sinuate tremae of the larval posterior spiracle (possible apomorphy of the few Aspistomella and Ulivellia whose larvae are known, but not found in the other Ulidiidae ), further supporting the inclusion of the genera Aspistomella and Ulivellia in a monophyletic lineage.

The species assigned here to the genera of the Aspistomella group have male genital structures so diverse that they would merit numerous separate genera, but we prefer to include most of them in the genera Aspistomella and Ulivellia . Morphology-based phylogenetic analysis does not provide a reliable resolution of their relationships, and the subdivision of this group into genera is tentative.

Many of the species discussed below are known from single specimens or only a few female specimens, so their descriptions lack male genitalia and can only be provisionally assigned to genera. Further study of additional material is required.