Anthrax nigriventris

Marston, 1970

Anthrax nigriventris is a of ( ) described by Marston in 1970. The species is characterized by its dark coloration, as indicated by the specific epithet 'nigriventris' (meaning 'black-bellied'). Like other members of the Anthrax, it is presumed to be a of ground-nesting , though specific records for this species have not been documented. The species occurs in arid and semi-arid regions of the southwestern United States, Mexico, and Cuba.

Pronunciation

How to pronounce Anthrax nigriventris: /ˈæn.θræks nɪˈɡrɪ.vɛn.trɪs/

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Identification

Distinguished from congeneric by the dark abdominal coloration referenced in its specific epithet. Within the Anthrax, identification to species level requires examination of abdominal color patterns and details. Distinguished from the similar genus Bombylius by wing venation characters, particularly the position of the r-m crossvein. Distinguished from Systoechus by seasonal activity patterns and wing venation; Anthrax species tend to be active in spring rather than fall.

Appearance

possess the typical : a single pair of membranous with the reduced to small knobbed structures called . The body is covered in , giving a fuzzy appearance that contributes to its -like . The specific epithet 'nigriventris' refers to dark or black coloration on the surface of the . includes the characteristic r-m crossvein used to distinguish within the tribe Bombyliini.

Habitat

Found in arid and semi-arid environments including desert scrub, grasslands, and open sandy areas. Associated with suitable for ground-nesting .

Distribution

Southwestern United States, Mexico, and Cuba. The disjunct distribution including Cuba suggests possible broader occurrence in Caribbean regions or historical biogeographic connections between southwestern North America and the Greater Antilles.

Behavior

are presumed to be flower visitors, obtaining nectar with an elongated . Females are presumed to locate burrows and near entrances, as is characteristic of the . are presumed to be of ground-nesting , attaching externally to host larvae and feeding on host tissues.

Ecological Role

As a presumed , likely contributes to of ground-nesting . flower-visiting may contribute to of flowering plants in arid .

Similar Taxa

Anthrax georgicusAlso a of ; distinguished by different abdominal coloration and distribution (eastern United States)
Anthrax analisClosely related with documented of ; distinguished by morphological details of abdominal patterning
Bombylius speciesSimilar -like appearance and flower-visiting ; distinguished by , particularly position of r-m crossvein, and often by seasonal activity (Bombylius more spring-active)

More Details

Taxonomic note

The specific epithet 'nigriventris' is a Latin compound meaning 'black-bellied,' directly describing the diagnostic dark coloration of the .

Data deficiency

This is notably data-deficient compared to better-studied such as A. georgicus and A. analis. No records, larval descriptions, or detailed behavioral observations have been published. The absence of iNaturalist observations suggests either genuine rarity, identification difficulty, or under-sampling of its .