Bombus dilectus, Zhang, 1994, species inquirenda

Dehon, Manuel, Engel, Michael S., Gerard, Maxence, Aytekin, A. Murat, Ghisbain, Guillaume, Williams, Paul H., Rasmont, Pierre & Michez, Denis, 2019, Morphometric analysis of fossil bumble bees (Hymenoptera, Apidae, Bombini) reveals their taxonomic affinities, ZooKeys 891, pp. 71-118 : 71

" Bombus " dilectus Zhang, 1994, species inquirenda

Holotype.

Female. Plate XXXIII-3, figs 168, 169 from Zhang et al. (1994). We were not able study the holotype (see comment under B. luianus , vide supra).

Type strata and locality.

Middle Miocene (i.e., 17.0-15.2 Ma), deposit of the Shanwang Formation, large lacustrine and lithified deposit, with diatomaceous and tuffaceous mudstone. Located in Linqu County, Shanwang Province, China.

Description.

Taken from Zhang et al. (1994): Forewing and hind wing membrane papillate distally; forewing membrane dark brown; forewing length more than 15.0 mm, maximum width more than 6.0 mm as preserved; basal vein slightly curved, basad cu-a; cu-a very slightly curved apically; marginal cell length approximately 5.0 mm; 1st abscissa of Rs slightly curved apically near midpoint; 2nd abscissa of Rs curved apically near midpoint; r-rs straight; Rs+M straight and longer than r-rs; 3Rs straight and smaller than r-rs; 4Rs almost as long as Rs+M; three submarginal cells; 1rs-m straight; 2rs-m curved apically in its posterior half; 1m-cu straight, reaching M near midpoint between 2nd abscissa of Rs and 1rs-m; 2rs-m curved and reaching M basad to 2rs-m; total body length approximately less than 20.0 mm as preserved. The original description and figure do not display a transector vein. See Zhang et al. (1994) for original description.

Comments.

The specimen was first described as B. dilectus by Zhang et al. (1994) and was stated to be similar to B. anacolus in that the wing color of both fossil species is rather dark and not transparent, or at most semi-transparent at the wing margins, a character differing from that of living species. However, some extant species display fairly dark wings (e.g., B. (Melanobombus) simillimus Smith, 1852). The authors also stated that the wings and body color of B. dilectus are darker than B. anacolus. As observed for B. luianus , results based on geometric morphometric analyses for this species (i.e., similarity to subgenus Bombus ) could be wrong, since it was based on Zhang’s drawings. Given this, we consider this fossil as species inquirenda.