Scrapter acanthophorus Davies, 2005

Davies, G. B. P., Eardley, C. D. & Brothers, D. J., 2005, Eight new species of Scrapter (Hymenoptera: Apoidea: Colletidae), with descriptions of S. albifumus and S. amplispinatus females and a major range extension of the genus, African Invertebrates 46, pp. 141-141 : 153-155

Scrapter acanthophorus Davies , sp. n.

Figs 4–8

Etymology: Gr. akantha (thorn); Gr. phero (bearer, carrier). In allusion to the distinctive spurred metatibia ( Fig. 4 ).

Holotype ơ: SOUTH AFRICA: Western Cape: 30 km north of Vanrhynsdorp (31°22'23"S: 18°42'37"E), Knersvlakte , 146 m, 6.ix.2003, K. Timmermann ( SANC) . Paratypes: 17 ơ collected from the same locality, between 5–11.ix.2003 ( MKPC) .

Description:

Male.

Measurements (n = 3): head length 1.3 mm, head width 1.7 mm, lower interocular distance 0.9 mm, upper interocular distance 1.1 mm, interantennal distance 0.3 mm, antennocular distance 0.2 mm, length of clypeus 0.4 mm, length of eye 1 mm, width of eye (lateral view) 0.5 mm, width of gena (lateral view) 0.2 mm, length of facial fovea 0.2 mm, maximum width of facial fovea 0.03 mm, mesoscutum length 1 mm, mesosoma length 1.6 mm, forewing length 4.2 mm, length of pterostigma 0.7 mm, maximum width of pterostigma 0.2 mm, length of marginal cell beyond pterostigma 0.9 mm, length of marginal cell 1.1 mm, length of free-part of marginal cell 0.8 mm.

Vestiture: Clypeus and lower paraocular area with thick, decumbent, bristly, white, hairs (underlying integument obscured). Remainder of paraocular area, frons, scape and vertex with erect, sparse, greyish, plumose hairs. Gena with sparse, white, plumose hairs. Mesoscutum, scutellum and metanotum covered in sparse, erect, shortish, whitish, plumose hairs (integument easily visible). Mes- and metepisterna with long, sparse, white, plumose hairs. T2–T5 with bands of white tomentum along graduli. Sterna largely hairless, S4 and S5 with very weak posterior hair bands, S6 with weak posterior brush of yellowish hairs on apical point of sternum.

Integumental colour: Mainly black. Anterior part of protibia and extreme apical end of profemur yellow. Extreme apical end of mesofemur yellow. Antenna ventrally yellow.

Head: Clypeus smooth (except dorsally where finely reticulate) with dense punctation (interspace <0.5 × puncture diameter), no clypeal sulcus. Supraclypeal area weakly raised, anterior face of supraclypeal area with weakly reticulated surface and rather sparse punctation (interspace approximately 1.5 × puncture diameter). Frontal line carinate. Frons and paraocular area with dense punctation. Facial fovea sulcoid. Ocellar triangle raised in anterior profile. Gena narrower than eye (0.4:1), with heavy punctation and reticulate sculpture. Inner eye orbits diverging dorsally, proportion of lower to upper interocular distance 0.8:1. F1 not elongate.Antenna short, barely reaching tegula.

Mesosoma: Mesoscutum, scutellum and metanotum with fairly dense to dense punctation (interspace 0.5–1 × puncture diameter), interspaces shiny and very finely reticulate, median line fairly broad but not deeply impressed, notaulus very weak. Mes- and metepisterna with dense punctation and reticulate interspaces. Propodeum strongly angulate, with dense punctation and rough, reticulate sculpture, propodeal triangle with uniform, rugose sculpture and weak anterior carinae on basal area, margins of triangle pitted.

Metasoma: Tergal discs with finely reticulate sculpture and evenly punctate (interspace 0.5–1 × puncture diameter). T2 fovea elongate ovoid.

Terminalia: Gonobase large, gonoforceps rather narrow, laterally concave, hairy (>30 golden hairs), ventrally with transparent membrane, penis valves large, prominent and outer margin ridged ( Fig. 5 ). S6 broadly rounded and hairy posteriorly, anteriorly weakly concave ( Fig. 6 ). S7 weakly concave posteriorly, inconspicuous pointed lateral processes bearing tiny tuft of hair ( Fig. 7 ). S8 posteriorly rounded, posterior region short, very weakly hairy ( Fig. 8 ).

Legs: Metabasitibial plate entire.Claws deeply cleft. Metatibia with pronounced posterior spur ( Fig. 4 ).

Female. Unknown.

Diagnosis: S. acanthophorus runs to S. albitarsis (Friese) in Eardley’s (1996) key, but is substantially larger with much denser scutal punctation and different terminalia (see Eardley 1996, figs 24–26), e.g. S. acanthophorus lacks the posterolateral prominences of the S7 found in S. albitarsis ( Eardley 1996, fig. 24). Further, S. albitarsis lacks the black spur on the metatibia characteristic of S. acanthophorus ( Fig. 4 ). Several other Scrapter species have males with armed hind legs, but they differ substantially from S. acanthophorus in general facies. S. heterodoxus (Cockerell) is a large, extremely hairy bee, easily distinguished by its strongly swollen metafemur and different terminalia (see Eardley 1996, figs 46–49). S. armatipes (Friese) and S. amplitarsus (Friese) both differ from S. acanthophorus in having swollen metabasitarsi, and in terminalia structure (see Eardley 1996, figs 100–107). S. aureiferus Cockerell is a tiny bee (body length 5–6 mm) with bright yellow legs, quite different from S. acanthophorus . Finally, S. acanthophorus has features suggestive of the S. nitidus complex (e.g. raised ocellar triangle, slit-like facial fovea, entire metabasitibial plate and basal pubescence along graduli on T2–T4), but the reticulate mesoscutum, lack of a clypeal sulcus, propodeal triangle largely devoid of carinae and spurred metatibiae easily distinguishes S. acanthophorus .

Distribution: Only known from the Knersvlakte, near Vanrhynsdorp, Western Cape. The Knersvlakte is a remarkable region framed in the east by the Bokkeveld Mountains and in the west by the coastal Strandveld. The landscape is one of low rounded hills and lightly undulating flats, covered in many areas with white quartz gravel and pebble fields, that give the area a distinctive appearance.The vegetation is sparse, low, dominated by succulents and rich in endemics ( Van Wyk & Smith 2001: 52–57). Little is known about the general insect fauna of the Knersvlakte, but endemic flies include the uncommon vermileonid Leptynoma namaquaensis (Stuckenberg) and empidid Edenophorus simplex Sinclair ( Stuckenberg 1996; Sinclair 2002). Furthermore, no less than four Scrapter species appear endemic to this region, viz. S. acanthophorus sp. n., S. calx Eardley , S. glarea sp. n. and S. sittybon sp. n. This apparent locus of Scrapter endemism may be an artifact of collection, and further collecting may show that these Scrapter species have a wider distribution.

Biology:All specimens have been collected in early September. Several of the paratypes were collected in yellow pan traps. No data on the flower preferences of this species is available.

Figures

Fig. 4. Scrapter acanthophorus sp. n., distinctive spurred metatibia (arrowed).

Figs 5–8. Scrapter acanthophorus sp. n., terminalia: (5) genitalia (dorsal and ventral views), (6–8) S6–S8. Scale bar = 0.4 mm.