Scrapter Lepeletier & Serville, 1828

Kuhlmann, Michael, 2014, Revision of the euryglossiform species of the Afrotropical bee genus Scrapter Lepeletier & Serville, 1828 (Hymenoptera: Apoidea: Colletidae), European Journal of Taxonomy 95, pp. 1-69 : 3-4

Genus Scrapter Lepeletier & Serville, 1828

Scrapter Lepeletier & Serville, 1828: 403 (not Scrapter Lepeletier, 1841: 260 ). Type species: Scrapter bicolor Lepeletier and Serville, 1828 , by subsequent designation in Vachal (1897: 63). (For later type designations and confusion with Scrapter Lepeletier , see Michener 1997.)

Polyglossa Friese, 1909: 123 . Type species: Polyglossa capensis Friese, 1909 , by subsequent designation in Cockerell (1921: 203). (For a later type designation by Sandhouse, see Michener 1997.)

Strandiella Friese, 1912: 181 . Type species: Strandiella longula Friese, 1912 = Scrapter niger Lepeletier & Serville, 1828 , by subsequent designation in Cockerell (1916: 430).

Polyglossa (Parapolyglossa) Brauns, 1929: 134 . Type species: Polyglossa heterodoxa Cockerell, 1921 , by subsequent designation in Sandhouse (1943: 584) (see Michener 1997).

Detailed diagnoses and descriptions of Scrapter were provided by Eardley (1996), Engel (2005), Davies & Brothers (2006) and Michener (2007), so they are not repeated here. Regarding the availability of Scrapterini versus Scraptrinae see Ascher & Engel (2006). Scrapter shows an unusual level of intrageneric diversity, described in detail by Davies & Brothers (2006), so various authors suggested that after revision the genus could be split up into several (sub)genera ( Engel 2005; Melo & Gonçalves 2005; Michener 2007). The current system of species-groups suggested by Eardley (1996) does not convincingly reflect this diversity, as it partly contains morphologically heterogenous and presumably paraphyletic species-groups. The S. flavostictus -group is an example of such an inhomogeneous assemblage and includes the first described "euryglossiform" Scrapter , S. albitarsis . This species and its relatives are here transferred to a new species-group.

The group of "euryglossiform" Scrapter

The term "euryglossiform" Scrapter is introduced here for a group of morphologically monotonous species, including the smallest bees of the genus (3.5–7.0 mm), that are predominantly black, often with yellow markings on the legs. This species-group can also be referred to as the S. albitarsis -group, named after the first described species. In their body shape, sparse pilosity, surface sculpture and narrow groove-like facial fovea they superficially resemble andreniform Euryglossinae . These similarities might be convergent ( Michener 2007: 171) but potentially reflect the presumed sister-group relationship of the Australian Euryglossinae and Scraptrinae ( Almeida & Danforth 2009) .

The species of the "euryglossiform" Scrapter are characterized by a) a sulcus-like facial fovea with an invisible bottom as in Hylaeus (e.g., Fig. 1D ), b) basitibial plate of female with simple marginal carinae, c) body small, without metasomal hair bands in females and most males, and d) membraneous apicolateral lobes on male S7 (e.g., Fig. 5D ), sometimes reduced to small structures, in nine of the 14 species where the males are known. In other Scrapter species these lobes, that are a common feature in many colletid genera, are only known in a much more reduced form from some species of the S. nitidus -group. This group also shares the narrow facial fovea and the shape of male genitalia with the "euryglossiform" Scrapter and might be their closest relatives as Davies et al. (2005) already suggested in their description of S. acanthophorus .

As relationships of species within the "euryglossiform" Scrapter are not clear, they are listed in alphabetical order.

Species of "euryglossiform" Scrapter

Figures

Fig. 1. Scrapter acanthophorus Davies, 2005, ♀. A. Lateral view. B. Metasoma (dorsal view). C. Head. D. Head (SEM). E. Thorax (dorsal view). F. Thorax (dorsal view, SEM). Scale bars: photos: 1 mm, SEM: 0.1 mm.

Fig. 5. Scrapter albitarsis (Friese, 1909), ♂. A. Lateral view. B. Genitalia (dorsal view, SEM). C. Metasoma (dorsal view). D. S7 (dorsal view, SEM). E. S8, apical end (SEM). F. S8, apical end (SEM). Scale bars: photos: 1 mm, SEM: 0.1 mm.