Acnephalomyia Londt, 2010

Blee, Tayler, Cabrero, Allan & Dikow, Torsten, 2025, Namib Desert Asiloidea (Diptera) 1. A review of the assassin-fly genus Acnephalomyia Londt, 2010 (Asilidae) with the description of a new species, African Invertebrates 66 (2), pp. 251-271 : 251-271

Acnephalomyia Londt, 2010

Acnephalomyia Londt, 2010: 438. Type-species: Dasypogon andrenoides Wiedemann, 1828, by original designation.

Links.

ZooBank https://zoobank.org/ 03F3BD7D-4AE2-4E9B-968E-00B35E635075.

GBIF https://www.gbif.org/species/8748144

Plazi TreatmentBank https://treatment.plazi.org/id/ FA455017-FFE3-AD73-FE05-760F4E09FEC4.

iNaturalist https://www.inaturalist.org/taxa/1125677-Acnephalomyia.

Diagnosis.

The genus can be delineated by the greatly reduced, but still discernible pulvilli, the presence of an empodium, open cells r 1, r 5 and m 3, vein C terminating at point where CuA + CuP reach wing margin, the abdomen (somewhat to obviously) dorso-ventrally flattened with female and male terminalia retracted and not easily visible, females with acanthophorite spines and a humpbacked appearance of the majority of species.

Distribution, biodiversity hotspots, endemism, seasonal imago flight activity and biology.

Known from the western parts of southern Africa in Namibia and South Africa (see Londt (2010): fig. 64). A relatively commonly observed and collected genus with 27 observations at iNaturalist (Table 2 ). Species of Acnephalomyia are known to occur in the Cape Floristic Region, Succulent Karoo and Maputaland-Pondoland-Albany biodiversity hotspots (see Londt (2010): fig. 64), but also occur outside of these hotspots. The genus is not endemic to a particular hotspot, environment or country. Adult flies are active from winter (July) to summer (February) (see Londt (2010), Table 3 ). Very little is known of the biology. Prey records cited by Londt (2010) include Coleoptera , Diptera, Heteroptera, Isoptera and Orthoptera .

Within the southern Namib Desert, species of Acnephalomyia are somewhat rarely collected from either the northern or southern parts (Figs 2 B , 11 ). Four species are known to occur in the southern Namib Desert, of which two are endemic. Adult flies are active in late winter (August) and throughout spring (September – October) with one record in November (Table 3 ).

Remarks.

Londt (2010) described Acnephalomyia iota and mentioned: “ A tiny black species not to be confused with any other [species] ”. Identification of this small species to the genus Acnephalomyia is not straightforward given the most recent key in Londt and Dikow (2017 a) as the stump vein R 3 (supernumerary cross-vein) at the base of R 4 is not present, which is a feature that the majority of Afrotropical Willistonininae genera with reduced pulvilli possess, i. e. Acnephalomyia , Sisyrnodytes Loew, 1856 and Sporadothrix Hermann, 1908 and which is absent in Ammodaimon Londt, 1985 and Astiptomyia Londt, 2010 ( Londt and Dikow 2016). The same is true for A. metallicoindica sp. nov., which initially was not recognised and identified by the authors as belonging to Acnephalomyia . In part, also because the abdomen is not ‘ obviously dorso-ventrally flattened’ and expanded laterally as in other, more ‘ regular’ Acnephalomyia species (a character used by Londt (2010) and Londt and Dikow (2017 a)). Therefore, an updated identification key to the genera of Afrotropical Asilidae ( Londt and Dikow 2017 a) has been developed and is available electronically with photographs and links to further resources at keys. lucidcentral. org / keys / v 4 / afrotropical-asilidae-dichotomous. A new set of couplets 34–37 of the Londt and Dikow (2017 a) key that help identify the Willistonininae genera with reduced pulvilli is provided below.

Figures

Figure 2. Maps of west-central Namibia with satellite imagery, major road network, major towns and watercourses (blue stippled to indicate non-permanent water flow). A. Study area southern Namib Desert highlighted in green (see text for details, blue circle = Gobabeb Namib Research Institute, K = Kuiseb Pass, So = Solitaire, Se = Sesriem, H = Helmeringhausen, A = Aus); B. Distribution of all Acnephalomyia specimens within the southern Namib Desert. White outline = type localities.

Figure 11. Distribution of Acnephalomyia species in the southern Namib Desert. A. Acnephalomyia andrenoides, red circles, A. metallicoindica sp. nov., purple circles; B. A. eremia, red circles, A. platygaster, purple circles. White outline = type locality. Occurrence data available at GBIF (dataset https://www.gbif.org/dataset/aef90774-efd0-4629-80ce-85bc4cbe24e8, DOI 10.15468/2bbawn).