Dromaeolus Kiesenwetter, 1858

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 : 22-23

Genus Dromaeolus Kiesenwetter, 1858

(= Melanus Broun, 1881 )

(= Megathambus Reitter, 1911 )

Diversity and distribution. More than 200 species are presently assigned to Dromaeolus . Many species are distributed largely in the tropical and subtropical regions around the globe. The greatest diversity of the group is concentrated in the African, Neotropical and Indo-Malaysian regions. Eight species are known in the Nearctic region. Nine species are distributed in the Palearctic region. In Costa Rica, in addition to four newly described species, there are 13 other species present: Dromaeolus ambiguus Bonvouloir ( Figure 41 ), D. cinerescens Bonvouloir ( Figure 42 ), D. dilutipes Bonvouloir ( Figure 43 ), D. fastidiosus Bonvouloir ( Figure 44 ), D. morens Horn ( Figure 45 ), D. ornatulus Horn ( Figure 46 ), D. panamensis Fisher ( Figure 47 ), D. pusio Horn ( Figure 48 ), D. sallei Bonvouloir ( Figure 49 ), D. tetricus Horn ( Figure 50 ), D. tripartitus Horn ( Figure 51 ), D. vanus Horn ( Figure 52 ) and D. variegatus Bonvouloir ( Figure 53 ). Five other described Central American species may be present but haven’t been collected in Costa Rica yet.

Diagnosis. Apical margin of frontoclypeal region feebly trilobed and more than twice as wide as the distance between antennal sockets; well-developed basally open or basally closed lateral antennal grooves present; male protarsomere I simple with basal sex combs; metacoxal plates medially 1.2–2.5 times wider than laterally; frons simple or with median carina present; last visible ventrite either rounded or truncated; tarsal claws simple; lateral surfaces of meso- and metatibiae either with setae and transverse rows of spine combs or setae and irregularly placed spines; male aedeagus dorsoventrally compressed, with laterally attached secondary lateral lobes; median lobe simple, with moderately and narrowly bifurcate apices; lateral lobes simple, entire; aedeagal flagellum simple ( Muona 1993, 2011; Otto 2016).

Note. Dromaeolus is paraphyletic, based on plesiomorphic traits ( Otto 2017b). Many species presently assigned in the group are misplaced. A revision of the group on a global scale is necessary to stabilize the group, in which the number of true Dromaeolus will be much fewer than the current numbers presently assigned to the group once the group is revised.

Figures

Figures 40–43. Costa Rican macraulacine eucnemids. 40) Absensiugum brunneum sp. nov., female allotype, dorsal habitus. 41) Dromaeolus ambiguus, dorsal habitus. 42) Dromaeolus cinerescens, dorsal habitus. 43) Dromaeolus dilutipes, dorsal habitus. (Scale: 40–43 = 1.0 mm)

Figures 44–49. Costa Rican Dromaeolus species. 44) Dromaeolus fastidiosus, dorsal habitus. 45) Dromaeolus morens, dorsal habitus. 46) Dromaeolus ornatulus, dorsal habitus. 47) Dromaeolus panamensis, dorsal habitus. 48) Dromaeolus pusio, dorsal habitus. 49) Dromaeolus sallei, dorsal habitus. (Scale: 44, 46–49 = 1.0 mm; 45 = 5.0 mm)

Figures 50–53. Costa Rican Dromaeolus species. 50) Dromaeolus tetricus, dorsal habitus. 51) Dromaeolus tripartitus, dorsal habitus. 52) Dromaeolus vanus, dorsal habitus. 53) Dromaeolus variegatus, dorsal habitus. (Scale: 50–53 = 1.0 mm)