Taxonomic revision records Feuerborniella from Tanzania

A taxonomic revision of the psychodid fly genus Feuerborniella has documented the genus in the Afrotropical Region for the first time, describing a new species from Tanzania’s West Usambara Mountains. Based on preserved museum specimens and detailed examination of wing, antenna and male genitalia, the study also revises the genus diagnosis and transfers three previously named species into Feuerborniella. The researchers conclude that several older placements still require case-by-case evaluation because the boundaries of related genera remain uncertain.

Feuerborniella was established by Vaillant in 1971 with the European species Psychoda obscura, now known as F. obscura, as its type species. The original definition also included two species from Brazil and one from the Malay Archipelago, but the boundaries of the group remained unclear for many years because of its close relationship with Quatiella and differing interpretations of generic limits within Psychodini and Trichopsychodina. The revision follows diagnoses published by Ježek in 1985 and Ibáñez-Bernal in 2004, supplementing them with a redescription of the type species based on European material.

The revised diagnosis identifies a combination of features intended to distinguish Feuerborniella from related psychodid genera. Its eyes are separated, while antennal flagellomeres 11–14 are reduced in size and may be fused or separate. The labellum is fleshy in both sexes and carries spines and hairs but lacks blunt teeth.

The wing membrane is not hairy, the fifth radial vein reaches the wing apex, and the male genitalia include widely separated gonocoxites, a symmetrical aedeagus and symmetrical parameres. A surstylus longer than the epandrium and bearing one terminal tenaculum provides another diagnostic feature. The revision adds the criteria of an unpilose wing membrane and symmetrical male genitalia to earlier definitions.

Several traits proposed in a 2015 redescription were found to be unsuitable as generic criteria. Some were polymorphic within Feuerborniella, and the fusion of antennal flagellomeres 11 and 12 also occurs in other members of Psychodini. Moreover, the type species itself did not conform to that diagnosis: its flagellomeres 11 and 12 are separated, and the female cerci are equal to or slightly shorter than the width of the genital plate.

The authors therefore did not recognize that diagnosis as consistent with the type species and assessed the many subsequent combinations made under it individually rather than treating them as automatically valid. The redescription of F. obscura was based principally on a male specimen from Schlitz in the Vogelsberg district of Hesse, Germany, while other European specimens were examined to confirm the generic characters. In the measured male, the wing was 1.63 mm long and 0.65 mm wide, and the head measured 0.30 mm in length and 0.32 mm in width.

The species has complete wing forks, a narrow ejaculatory apodeme, dorsally connected parameres extending to the apical fifth of the aedeagus, and no subapical constriction in the aedeagus. Its male terminalia include a plate-like hypandrium, cylindrical gonocoxites and gonostyli, and conical surstyli with a single spatulate tenaculum. Vaillant described them as Y-shaped on the first ten flagellomeres and either Y-shaped or V-shaped on subsequent segments, whereas Ježek illustrated a two-branched condition and Krek depicted three branches without noting the V-shaped variant.

The revision treats the number of branches as variable, consistent with Vaillant’s later account. The redescription also records separated eyes, an inverted Y-shaped interocular suture, a bulbous and setose labellum without teeth, a hyaline wing with an infuscated costal cell, and a ratio of 2.8 between wing length and width. The newly described species, Feuerborniella sinefurcata, is based on a single male holotype collected by Malaise trap at Loc G and F in the Mazumbai Forest Reserve, Tanga Region, in Tanzania’s West Usambara Mountains.

It is the 19th psychodid species described from those mountains and the second Afrotropical member of Feuerborniella. The name combines the Latin words for “without” and “fork,” referring to reduced radial and medial wing forks. Its wings measured 1.50 mm long and 0.63 mm wide, and its head measured 0.28 mm long and 0.29 mm wide.

The incomplete forks, narrow ejaculatory apodeme, separated parameres and unconstricted aedeagus distinguish it from the other recognized species. The transfer of F. morogorica was supported by its bulbous labellum, symmetrical aedeagus and parameres, widely separated gonocoxites, and surstylus bearing a single tenaculum. This species can be distinguished by complete wing forks, a narrow ejaculatory apodeme, parameres that do not extend beyond the gonocoxites, and an aedeagus without a subapical constriction.

Those exclusions remain provisional rather than representing formal transfers. The revision notes that the three excluded species may belong to Nielseniella, but the generic limits of that genus must first be reassessed through examination of its type species. The placement of Psychoda nigripennis, transferred to Feuerborniella by Ježek in 1985, is also uncertain because its original description was inadequate and the available female type material was damaged when it was revised by Quate.

Of the 14 species the authors considered members of Feuerborniella, 11 are Neotropical, one is Palearctic and two are Afrotropical. Numerous undescribed specimens encountered in the Zurquí project suggest that the genus may be especially diverse in the Neotropical Region. The Tanzanian record makes existing identification keys for Afrotropical Psychodini incomplete.

In keys published by Kvifte in 2015 and by Kvifte and Wagner in 2017, Feuerborniella leads to a couplet based on the number of surstyli tenacula, even though the genus has only one tenaculum and therefore fits neither option in the key. Among Afrotropical Psychodini, the authors instead identify it by the combination of a bulbous rather than flat labellum and a surstylus carrying a single tenaculum. The paper therefore provides a revised regional distinction while showing that the placement of several species remains contingent on further examination of type material and the boundaries of Nielseniella.

Subject of Research: Taxonomic revision of the psychodid fly genus Feuerborniella using preserved museum specimens

Article Title: Revisionary notes on Feuerborniella Vaillant, 1971, with the first record of the genus from the Afrotropical region ( Diptera , Psychodidae )

Article References: Kvifte, G. M., & Jaume-Schinkel, S. (2023). Revisionary notes on Feuerborniella Vaillant, 1971, with the first record of the genus from the Afrotropical region (Diptera, Psychodidae). Deutsche Entomologische Zeitschrift, 70(1), 121-127. https://doi.org/10.3897/dez.70.97465

Image Credits: AI Generated

DOI: 10.3897/dez.70.97465

Keywords: Feuerborniella, taxonomic revision, new species, Tanzania, Afrotropical Region, Psychodidae, West Usambara Mountains, Diptera, morphology, species classification, Revisionary, notes