Larrisson tibialis Pulawski, 2012

Pulawski, Wojciech J., 2012, A review of the genus Larrisson Menke, 1967, and description of the new genus Larrissa (Hymenoptera, Crabronidae), Journal of Hymenoptera Research 25, pp. 35-82 : 65-66

Larrisson tibialis Pulawski sp. n. Figs 18 21

Name-derivation.

Tibialis is a Latin adjective derived from tibia; with reference to the unusual male hindtibia of this species.

Recognition.

The male of tibialis (the female is unknown) has uniquely modified hindtibia, thickened on the outer side at about one third length (the thickening is best seen in dorsal view, Fig. 21a ), and the lateral surface has three unevenly spaced spines: two at the thickening and one near the apex ( Fig. 21a, b ). In the other Larrisson , the hindtibia is not thickened, and the spines on the lateral surface are evenly spaced. Subsidiary recognition characters of tibialis are: propodeal dorsum with spine behind spiracle and sternum II with arcuate swelling.

Description (based on holotype only).

Male. Width of face across clypeus and vertex = 60:58, least interocular distance 35. Orbital fovea well defined, narrower than half ocellocular distance. Clypeal lobe only slightly prominent, its free margin arcuate, not angulate laterally. Scapal basin impunctate except punctate along inner margin. Length of scape (excluding radicle) 2.8 × width, length equal to flagellomeres I-V combined. Flagellomeres cylindrical. Mesopleuron with convexity in front of midcoxa; mesothoracic venter sparsely punctate on each side of median zone (punctures several diameters apart). Metanotum with small median tooth. Propodeal side ridged; posterior surface ridged both mesodorsally and medioventrally. Outer surface of hindtibia sparsely punctate and setose between spines. Tergum I concave basally.

Setae all silvery, appressed on head, thorax, propodeum, and legs, nearly completely concealing integument on clypeus (except glabrous ventral portion of median lobe) and on ventral half of frons laterally (scapal basin glabrous), largely concealing integument on mesopleuron and mesothoracic venter, not forming apical fasciae on terga. Hindfemoral venter asetose, inner (= posterior) surface setose except asetose along ventral margin in basal half.

Head, thorax, and propodeum black except the following are pale yellow: scape ventrally, pedicel apically, mandible (except apically), and pronotal lobe, whereas flagellum is black dorsally and brown ventrally. Forefemur black, pale yellow in apical third; foretibia and foretarsus pale yellow; midfemur reddish brow, black basoventrally, pale yellow apically; midtibia reddish brown, pale yellow basally and apically; midtarsus pale yellow, apical tarsomere brown; hindfemur reddish brown, black basally; hindtibia reddish brown; hindtarsus yellow, apical tarsomere brown. Gaster black except tergum I and preapical zone on terga II and III reddish brown.

Posterior mandibular margin not expanded between base and notch, inner margin with small tooth near midlength. Flagellum cylindrical; dorsal length of flagellomere I about equal apical width. Propodeal dorsum with spine behind spiracle. Legs unmodified except midtibia slightly curved near basis, hindfemur with small emargination near apex of externoventral (= anteroventral) margin, carinate between ventral and posterior (= inner) surfaces, venter concave; hindtibia thickened on the outer side at about one third length (thickening best seen in dorsal view, Fig. 21a ), with densely punctate area on lateral surface between thickening and apex that is gradually enlarging toward apex, and lateral surface with three unevenly spaced spines: two at thickening and one near apex ( Fig. 21a, b ); forebasitarsus with four rake spines; apical spine of forebasitarsus III as long as apical basitarsal width. Sternum II with arcuate swelling, anterad of swelling with dense, erect setae that are shorter than midocellus width; sterna III-VII with long, erect setae at bases of apical depressions, sterna VI and VII also with numerous erect setae that are about as long as midocellar width. Sternum VIII punctate and setose along margin, rounded apically. Genitalia similar to those of quintus except volsella ending shortly before apex of penis valve. Length 9.5 mm.

Female. Unknown.

Geographic distribution

( Fig. 18 ). Known from one locality in South Australia.

Specimen examined.

Holotype: ♂, AUSTRALIA: South Australia: Calperum Station 31 km NW Renmark at 33°59'S, 140°30'E, 7 Nov - 13 Dec 1995, K.R. Pullen (ANIC).

Figures

Figure 18. Collecting localities of Larrisson sulcatus, tibialis, and variegatus.

Figure 21. Larrisson tibialis ♂: a hindtibia in dorsal view b hindtibia in lateral view.