Wainia (Caposmia) gessorum Kuhlmann, 2011

Kuhlmann, M., Gess, F. G., Koch, F. & Gess, S. K., 2011, Southern African osmiine bees: taxonomic notes, two new species, a key to Wainia, and biological observations (Hymenoptera: Anthophila: Megachilidae), Zootaxa 3108, pp. 1-24 : 18

Wainia (Caposmia) gessorum Kuhlmann spec. nov.

( Figs 4a–f, 6e–h)

Wainia (Caposmia) sp. C.: Gess and Gess 2008: 101, 102, 104 (nesting in snail shells).

Diagnosis. The species is the smallest in the subgenus Caposmia in southern Africa. The diagnosis is given in the form of a key for species identification including all southern African Wainia species.

Description

Female. Bl = 7.0– 7.5 mm. Head. Head about as long as broad. Integument black except mandibles medially dark reddish-brown. Face medially with long, erect reddish-brown setae. Mandibles tridentate ( Fig. 6e). Clypeus sparsely covered with reddish-brown setae, vertex with sparse long, erect reddish-brown pilosity. Clypeus slightly convex, densely and finely punctate, surface between punctures shiny, apical margin impunctate and truncate ( Fig. 6e). Paraocular area moderately finely and densely punctate (i <0.5d); surface between punctures smooth and shiny. Antennae black, ventrally apical segments orangish-brown. Mesosoma. Integument black. Scutum densely and finely punctate (i = 0.5d) between punctures smooth and shiny ( Fig. 6f); posterior lateral angle obtuse and with distinct lamella ( Fig. 6f). Scutellum as illustrated in Fig. 6f. Propodeum medially smooth and shiny ( Fig. 6g). Scutum, scutellum, metanotum, mesepisternum and propodeum with similar long reddish-brown, erect setae as on head. Wings. Slightly brownish transparent, veins and stigma dark brown. Legs. Integument black. Vestiture reddish-brown. Metasoma. Integument black except very narrow margins of terga brownish to reddish translucent, densely punctate ( Fig. 6h). Terga covered with erect reddish-brown hairs, but without apical tergal hair band ( Fig. 6h). Scopa bright orangish-brown.

Male. Bl = 6.5–7.5 mm. Head. Head about as long as broad. Integument black. Face densely covered with long, erect yellowish-brown setae, vertex with long, sparse yellowish-brown pilosity. Mandibles bidentate and clypeus with impunctate apical margin as in Fig. 4a. Paraocular area as in female. Antennae black. Mesosoma. Integument and pilosity as in female ( Fig. 4b). Wings. As in female. Legs. Integument black. Vestiture yellowishbrown. Metasoma. Integument and pilosity of terga as in female ( Fig. 4c). T7 with curved transverse preapical carina that is medially shallowly emarginate ( Fig. 4e). Metasomal sterna S3-S6 as illustrated ( Fig. 4d). Genitalia. Genitalia as illustrated ( Fig. 4f).

Type material (5 specimens). Holotype, female. 03/04/30, ex nest in Trigonephrus shell / NAMIBIA, W Obib Mountains, 28°07.83S 16°41.88E, 15.ix.2003, F.W. and S.K. Gess / Wainia (Caposmia) sp. C, det. F.W. Gess (handwritten) ( AMGS).

Paratypes. 1 ♀, 3 ♂ (1 ♂ in gelatine capsule pinned with ♂). Same dates as holotype, (2 ♂ AMGS; 1 ♂, 1 ♀ RCMK) .

Additional material (2 ♂ in gelatine capsules). 1 ♂, 05/06/29 / ex nest in Trigonephrus shells / NAMIBIA, Klinghardt Mountains, 27.19S 15.46E, 11.ix.2005, F.W. and S.K. Gess / Wainia (Caposmia) sp. C, det. F.W. Gess 2006 (handwritten) ( AMGS); 1 ♂, 05/06/24 ex [nest in] Trigonephrus shell / NAMIBIA, Klinghardt Mountains, 27.19S 15.46E, 10.ix.2005, F.W. and S.K. Gess / Wainia (Caposmia) sp. C, det. F.W. Gess 2006 (handwritten) ( AMGS).

Etymology. Named after Friedrich and Sarah Gess who collected this species.

Distribution. Only known from SW Namibia.

Flower visiting. Unknown.

Nesting. This bee was found nesting only in desertic areas north of the Orange River. Nests were in shells of Trigonephrus Pilsbry (Dorcasiidae) ( Gess and Gess 2008). Like Wainia (C.) atrorufa it constructs linearly arranged cells separated with a thin partition constructed from petal pieces arranged at right angles to the outer wall of the shell (voucher specimens AMGS). The pollen provision fills the entire cell and adheres to the shell wall. At the outer end of the nest there is a succession of thick partitions constructed from several layers of petal pieces followed by a layer of cemented sand. The final seal is very robust and is constructed similarly but with the sand layer much thicker and more heavily cemented. The nature of the bonding agent was not established.