Deltochilum (Deltochilum) Eschscholtz, 1822

Génier, François, 2012, A new species and notes on the subgenus Deltochilum (Deltochilum) Eschscholtz, 1822 (Coleoptera: Scarabaeidae: Scarabaeinae: Deltochilini), Zootaxa 3357, pp. 25-36 : 26

Deltochilum (Deltochilum) Eschscholtz, 1822

Eschscholtz 1822: 37 original description

Synonym: Telhyboma Kolbe, 1893 , new synonymy Kolbe 1893: 192 original description

Remarks. While examining species belonging to the subgenus Deltochilum , it became apparent that the status of the single species ( D. orbiculare van Lansberge) included in the subgenus Telhyboma Kolbe should be reconsidered. After a careful examination, it appears that the only apomorphic character separating D. orbiculare from all other species included in the subgenus Deltochilum is the development of the 7th interstrial carina. In D. orbiculare this carina is present on most of the length of the 7th interstria and overlaps the elytral edge and the 9th interstrial carina on most of the elytral length. The development of this carina is clearly linked to gender. Hyperthelic males always exhibit a much more developed structure than females, suggesting that the development of this carina in D. orbiculare is an additional secondary sexual character. In their study of the subgenera Calhyboma , Hybomidium and Telhyboma for Colombia, González et al. (2009) also noted the asymmetrical parameres and the additional internal sac sclerites, which conform to other species in the subgenus Deltochilum .

The following apomorphies define the subgenus Deltochilum in its current sense: overall body shape in dorsal view with widest portion at mid-distance or slightly past mid-distance to elytral apex; elytral surface with a distinct network of irregular glossy bulges (not glossy in D. enceladus Kolbe ) sharply contrasting from remaining surface; protibia lacking tarsus in both sexes; male protibia with a modification on internal edge basal third; male profemur with a teeth past mid-distance on internal edge; male mesofemur with a denticle on basal half; male metafemur with posterior surface completely matte, with punctures weakly impressed, more widely separated than remaining surface or absent; male sternite 3 with a strong bulging structure medially (note: this structure is absent in both Central American species, D. scabriusculum Bates and D. tumidum Howden. However , in some specimens of D. scabriusculum and D. tumidum the surface shows wrinkles that would correspond to the lateral edges of the bulge, suggesting that in these species there is a reversal to the primitive state); parameres with strong ventral projections, slightly asymmetrical.