Hypoborini
Nüsslin, 1912
Genus Guides
1Hypoborini is a tribe of small bark beetles (Curculionidae: Scolytinae) established by Nüsslin in 1912. Recent molecular and morphological revision of the Afrotropical fauna revealed substantial undescribed diversity, including three new and seven new . The tribe comprises two subtribes in the Afrotropical region: Xerasiborina (Xerasiborus, Nisiborus, tentatively Glochiphorus) and Hypoborina (Dacryostactus, Styracoptinus, Afrotrypetus, Corditarsus). Related Palearctic genera Hypoborus and Liparthrum occur in Mediterranean and Macaronesian regions. Phylogenetic analyses indicate an early Palaeocene origin with ancestral area split between Asia/Africa and Madagascar, followed by single of Madagascar and subsequent recolonization of the African mainland.
Pronunciation
How to pronounce Hypoborini: /haɪˌpɒbəˈraɪnaɪ/
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Identification
Hypoborini are distinguished from other Scolytinae tribes by a combination of morphological characters detailed in the 2021 revision. Members of subtribe Xerasiborina differ from Hypoborina in characters associated with the new -level Xerasiborus and Nisiborus. Identification to genus requires examination of subtle morphological differences in tarsal structure and body form; Corditarsus is characterized by distinctive tarsal modifications. Molecular data (COI and CAD sequences) support the tribal and subtribal groupings.
Habitat
Dead twigs and branches, mainly in dry forest.
Distribution
Afrotropical Region: Madagascar (multiple Xerasiborus , Nisiborus schaufussi), Tanzania (Xerasiborus zambesianus), South Africa (Afrotrypetus capensis). Related in warm Palearctic: Mediterranean, Macaronesia, and Atlantic islands (Hypoborus, Liparthrum).
Host Associations
- Euphorbia shrubs - Documented for related Macaronesian Liparthrum per Jordal 2006; not directly confirmed for Afrotropical Hypoborini in this source. epithet 'euphorbiae' suggests possible association.
Similar Taxa
- Other Scolytinae tribesHypoborini is distinguished by its combination of morphological characters and molecular phylogenetic placement; the 2021 revision established its monophyly relative to other bark beetle tribes.
More Details
Taxonomic revision
The 2021 molecular and morphological revision by Kusy et al. described three new (Xerasiborus, Nisiborus, Corditarsus), seven new , and established new subtribe Xerasiborina. This revealed that Afrotropical Hypoborini diversity was previously underestimated, with many having narrow geographical distributions.
Biogeographic history
Phylogenetic dating places the origin of Hypoborini in the early Palaeocene. The ancestral area was split between Asia/Africa and Madagascar. Madagascar was colonized once, followed by a single recolonization event of the African mainland. The Mediterranean and Macaronesian Liparthrum radiation occurred later, in the Oligocene.