Adelothyreus Chevrolat, 1867, 1868

Otto, Robert L., Muona, Jyrki & Córdoba-Alfaro, Jim, 2023, A new genus and sixteen new species of false click beetles (Coleoptera: Eucnemidae) described from the Heredia Province of Costa Rica with several additional records from the Osa Peninsula and Panama, Insecta Mundi 2023 (991), pp. 1-36 : 5-7

Genus Adelothyreus Chevrolat, 1867

Diversity and distribution. The small group consists of 17 species distributed worldwide, that are present in four ecoregions. Three species are known in the Nearctic region. A single species is present in the Southeast Asian region. One species is known from the African continent. One species is present in Madagascar. In the Neotropical region, including the Antilles, 11 species are known. This study adds three more species to that region. In Costa Rica, in addition to the three newly described species, there are several other species present: Adelothyreus comes Horn ( Figures 1–3 ), A. flavosignatus Bonvouloir ( Figures 4–6 ) and A. horni (Fleutiaux) ( Figures 7–9 ). Adelothyreus flavosignatus has not been observed in Heredia province, but is present elsewhere in Costa Rica and included in the identification key.

Diagnosis. Apical margin of frontoclypeal region evenly rounded and more than twice as wide as the distance between antennal sockets; apically wide notosternal antennal grooves present; male prothoracic tarsomere I simple, without sex combs; metacoxal plate parallel-sided; last visible ventrite produced, forming a beak; simple tarsal claws; lateral surfaces of meso- and metatibiae with setae only; male aedeagus dorsoventrally compressed, with basally attached secondary lateral lobes; median lobe simple, deeply and widely bifurcate apically; lateral lobes simple, longitudinally bilobed; aedeagal flagellum complex; tubular ( Muona 1993, 2011).

Adelothyreus are very similar to Quirsfeldia Cobos. The group can be distinguished from Quirsfeldia by the apical margin of the frontoclypeal region being more than twice as wide as the base. Quirsfeldia have apical margin of the frontoclypeal region less than twice as wide as the base.

Figures

Figures 1–6. Costa Rican Adelothyreus species. 1) Adelothyreus comes, dorsal habitus. 2) Adelothyreus comes, antenna. 3) Adelothyreus comes, pronotal lateral habitus. 4) Adelothyreus flavosignatus, dorsal habitus. 5) Adelothyreus flavosignatus, antenna. 6) Adelothyreus flavosignatus, pronotal lateral habitus. (Scale: 1–6 = 1.0 mm).

Figures 7–9. Adelothyreus horni. 7) Dorsal habitus.8) Antenna.9) Pronotal lateral habitus. (Scale: 7–9 = 1.0 mm).