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.

Key to species of "euryglossiform" Scrapter

Due to their small size, the similarity of many species and the subtle, often gradual differences between some of them, identification can be very difficult, particularly in females. For males it is generally recommended to dissect genitalia and hidden sterna S7 and S8.

Females

The females of S. glareus and S. minutissimus sp. nov. are unknown.

1 Stigma bright yellow (Fig. 11A) …………………………………………… S. luteistigma sp. nov.

– Stigma light to dark brown …………………………………………………………………………2

2 Apical tergal margins broadly brownish to yellowish translucent (Figs 1B, 28B, 32E); larger species ...……………………………………………………………………………………………3

– Apical tergal margins black or very narrowly brownish translucent; smaller species ……………5

3 Punctation on basal part of clypeus much finer than apically (Fig. 28 C–D); foretibia entirely or predominantly yellowish to reddish brown (Fig. 28A) ………………………… S. sittybon Davies

– Punctation on clypeus more evenly sized (Figs 1 C–D, 32B); foretibia dominantly dark blackishbrown (Figs 1A, 32A) ………………………………………………………………………………4

4 Metasomal terga between punctures smooth and shiny (Fig. 1B); clypeus distinctly convex (Fig. 1 C–D) …………………………………………………………………… S. acanthophorus Davies

– Metasomal terga between punctures finely sculptured, slightly matt (Fig. 32E); clypeus more flat (Fig. 32B) ………………………………………………………………………… S. ulrikae sp. nov.

5 Scutum sparsely and finely punctured, looking almost impunctate and shiny (Figs 6 E–F, 8E–F) ……6

– Scutum more densely and coarsely punctured ……………………………………………………8

6 Supraclypeal area, clypeus (Fig. 6 C–D) and mesepisternum only partially and superficially reticulate, more shiny …………………………………………………………… S. exiguus sp. nov.

– Supraclypeal area apically, clypeus basally (Fig. 8 C–D) and mesepisternum extensively and strongly reticulate, matt ………………………………………………………………………………7

7 Facial fovea slightly shorter than in S. gessorum sp. nov. (Fig. 4 A–B); a variable species with respect to surface sculture and punctation (Figs 3 C–F, 4A–D) ………… S. albitarsis (Friese)

– Facial fovea slightly longer than in S. albitarsis (Fig. 8D) ……………… S. gessorum sp. nov.

8 Clypeus and supraclypeal area matt, strongly reticulate, very sparsely, finely and shallowly punctate (Fig. 10 C–D) ……………………………………………………… S. inexpectatus sp. nov.

– Clypeus and supraclypeal area more shiny, only partly or superficially sculptured, punctation usually stronger and denser …………………………………………………………………………9

9 Metasomal terga finely and densely punctate, between punctures completely smooth and shiny (Fig. 18B) …………………………………………………………………… S. nigerrimus sp. nov.

– Metasomal terga either impunctate or with more dispersed/coarser punctation; if punctation is similar (some specimens of S. punctatus sp. nov.) then terga at least basally with superficial sculpture and slightly matt ………………………………………………………………………………………10

10 Metasomal terga impunctate (Figs 19E, 25E); scutum distinctly reticulate and shallowly punctate (Figs 19B, 25 C–D) ………………………………………………………………………………11

– Metasomal terga punctate, sometimes punctures minute (Fig. 26E); scutum either without reticulation or only very weakly reticulate ………………………………………………………12

11 Basal area of propodeum distinctly and largely carinate (Fig. 19B) …… S. nigritarsis sp. nov.

– Basal area of propodeum along anterior margin indistinctly carinate (Fig. 25 C–D) ……………… ………………………………………………………………………………… S. pygmaeus sp. nov.

12 Scutum covered with large punctures (Figs 23 C–D, 30C–D) …………………………………13

– Scutum covered with smaller punctures (Figs 14 E–F, 15C–D, 16E–F, 21C–F, 26C–D) ………14

13 Basal area of propodeum shorter, medially only slightly longer than metanotum; few, short and indistinct carinae (Fig. 23 C–D) ……………………………………………… S. punctatus sp. nov.

– Basal area of propodeum longer, medially about 1.5 times as long as metanotum; carinae longer and more distinct than in S. punctatus (Fig. 30 C–D) ……………………………… S. spinipes sp. nov.

14 Punctation of metasomal terga minute, almost invisible (Fig. 26E) ……… S. roggeveldi sp. nov.

– Punctation of metasomal terga much coarser and clearly visible (Figs 14B, 15E, 16B, 21 G–H) …15

15 Head distinctly broader than long (Figs 14 C–D, 16C–D) ………………………………………16

– Head about as long as broad (Figs 15B, 21B) …………………………………………………17

16 Clypeus, supraclypeal area and T1 mostly polished and shiny, only partially very finely and superficially sculptured, slightly matt (Fig. 14 B–D) ……………………… S. minutuloides sp. nov.

– Clypeus, supraclypeal area and T1 (particularly anteriorly) mostly finely sculptured and matt (Fig. 16 B–D) …………………………………………………………………… S. nanus sp. nov.

17 Metanotum apically more evenly rounded, without distinct carinate depression (Fig. 15D); fore tibia anteriorly largely yellowish-brown …………………………… S. minutus sp. nov.

– Metanotum apically with a carinate depression (Fig. 21D, F); fore tibia anteriorly blackish, only at the base with a small yellowish spot ……………………………… S. papkuilsi sp. nov.

Males

The males of S. gessorum sp. nov., S. inexpectatus sp. nov., S. minutuloides sp. nov., S. minutus sp. nov., S. nigerrimus sp. nov. and S. pygmaeus sp. nov. are unknown.

1 Antennal flagellum medially broadened, entirely orange (Fig. 12B); stigma bright yellow (Fig. 12A); S7 and S8 as in Fig. 12D, F …………………………………………… S. luteistigma sp. nov.

– Antennal flagellum not broadened, only partly yellowish; stigma darker …………………………2

2 Antenna long, last flagellar segment about twice as long as wide (Fig. 24E); S7 and S8 as in Fig. 24D, F ………………………………………………………………………… S. punctatus sp. nov.

– Antenna shorter, last flagellar segment at most 1.5 times as long as wide ……………………………3

3 Hind tibia inside apically broadened, pointed (Fig. 22E) or forming either a spine (Figs 2E, 31E) or a ± right angle (Fig. 27G) ………………………………………………………………………4 – Hind tibia unmodified, if apically broadened then without spine or ± sharp edge ……………7

4 Hind tibia inside apically forming a ± right angle (Fig. 27G); S4–S5 with conspicuously long apical hair fringes (Fig. 27E); S7 and S8 as in Fig. 27D, F ……… S. roggeveldi sp. nov.

– Hind tibia inside apically pointed (Fig. 22E) or forming a spine (Figs 2E, 31E) …………………5

5 Hind tibia inside apically pointed (Fig. 22E); scutum and metasomal terga finely punctate (Fig. 22C); S7 and S8 as in Fig. 22D, F ……………………………………………… S. papkuilsi sp. nov.

– Hind tibia inside apically with spine (Figs 2E, 31E); scutum and metasomal terga coarsely punctate (Figs 2C, 31C) ……………………………………………………………………………6

6 Hind tibia apically with longer spine (Fig. 31E); metasomal terga densely punctate (Fig. 31C); S7 and S8 as in Fig. 31D, F …………………………………………………… S. spinipes sp. nov.

– Hind tibia apically with shorter spine (Fig. 2E); metasomal terga sparsely punctate (Fig. 2C); S7 and S8 as in Fig. 2D, F ………………………………………………… S. acanthophorus Davies

7 Hind basitarsus brown to blackish …………………………………………………………………8 – Hind basitarsus yellowish …………………………………………………………………………11

8 Hind tibia apically slightly swollen and curved (Fig. 29E); scutum between punctures smooth and shiny; S7 and S8 as in Fig. 29D, F ………………………………………… S. sittybon Davies

– Hind tibia unmodified; scutum between punctures sculptured and matt ……………………………9

9 Basal half of T2–T4 densely covered with short, erect, silverish hair (Fig 33C); S7 and S8 as in Fig. 33 D–E …………………………………………………………………………… S. ulrikae sp. nov.

– Basal half of T2–T4 almost hairless (Figs 17C, E, 20C) …………………………………………10

10 Discs of metasomal terga impunctate, very finely and regularly sculptured (Fig. 20C); S7 and S8 as in Fig. 20 D–E ………………………………………………………… S. nigritarsis sp. nov.

– Discs of metasomal terga partly punctate, strongly to heavily and irregularly sculptured (Fig. 17C, E); S7 and S8 as in Fig. 17D, F …………………………………………… S. nanus sp. nov.

11 Hind tibia yellow with a brown spot on the back side (Fig. 9A, C); S7 and S8 as in Fig. 9 D–E …………………………………………………………………………………… S. glareus Davies

– Hind tibia mostly black (Figs 5A, 7A, 13A) ………………………………………………………12

The males of the following three species are very similar and can be best separated by S7 and S8.

12 S7 without membraneous apicolateral lobes (Fig. 13D); S8 as in Fig. 13E … S. minutissimus sp. nov. – S7 with membraneous apicolateral lobes (Figs 5D, 7D) ………………………………………13

13 S7 apically with emargination slightly broader and shallower (Fig. 5D) …… S. albitarsis (Friese) – S7 apically with emargination slightly narrower and deeper (Fig. 7D) ……… S. exiguus sp. nov.