Sphex corporosus, Doerfel, Thorleif H. & Ohl, Michael, 2015

Doerfel, Thorleif H. & Ohl, Michael, 2015, A revision of the Australian digger wasps in the genus Sphex (Hymenoptera, Sphecidae), ZooKeys 521, pp. 1-104 : 52-54

Taxon classification Animalia Hymenoptera Sphecidae

Sphex corporosus sp. n.

Material examined.

Holotype. ♂, AUSTRALIA:NSW: Pooncarie, 26.11.1992, N. W. Rodd (AMS). Paratypes. AUSTRALIA:NSW: "20 SW" of Bourke, 2♀, 1♂, 28.10.1949, E. F. Riek (ANIC); Broken Hill, 1♀, 27.02.1941, C. E. Chadwick (AMS), 1♂, 26.12.1942, C. E. Chadwick (AMS), 1♂, 31.10.1943, C. E. Chadwick (AMS), 1♂, 03.12.1947, C. E. Chadwick (AMS), 1♂, 11.11.1985, N. W. Rodd (AMS), Hay, 1♂, 27.11.1992, N. W. Rodd (AMS); 30 km N of Euston, 1♂, 28.11.1988, N. W. Rodd (AMS); 20 km N of Menindee, 1♀, 1♂, 10.11.1985, N. W. Rodd (AMS); Narromine, 1♀ (AMS); Pooncarie, 3♀, 1♂, 28.11.1992, N. W. Rodd (AMS); Round Hill Nature Reserve, 1♀, 27.12.1976, G. Daniels (AMS), 1♀, 25.10.1977, G. Daniels (AMS); 75 km W of Wilcannia, 4♂, 09.11.1985, N. W. Rodd (AMS); QLD: 20 S of Tickalara, 1♂, 14.09.1949, E. F. Riek (ANIC); SA: Adelaide, 1♀ (ZMB); Lake Gilles Conservation Park, 1♀, 01.02.1995, L. Packer, M. Schwarz, P. Hurst, Y. Pamula (ZMB); 60 km W of Nullarbor, 31°34'S, 130°15'E, 1♀, 14.12.1995, M. S. & B. J. Moulds & K. A. Kopestonsky (AMS); Wilpena Pound Resort, 1♀, 18.01.1976, M. S. & B. J. Moulds (AMS); VIC: [no specific locality], 1♀, 1909, C. French (ANIC); Swan Island, 1♂ (BMNH); WA: Champion Bay Beach, 1♂ (BMNH); Hamelin Telegraph Station, 26°23.9'S, 114°09.9'E, 1♀, 1♂, 08.11.2008, V. Ahrens & W. J. Pulawski (CAS), 3♂, 10.11.2008, V. Ahrens & W. J. Pulawski (CAS); Kalbarri National Park: Ross Graham Lookout, 27°48.6'S, 114°28.3'E, 1♂, 06.11.2008, V. Ahrens & W. J. Pulawski (CAS); Marloo Station, 1♀, 01.01.1936, A. Goerling (ZMB), 1♀, Feb–Mar 35, A. Goerling (ZMB), 1♀, Oct–Nov 34, Gebr. Goerling (ZMB); Shire of Northampton, Kalbarri National Park, 27°39'13"S, 114°27'24"E, 1♀, 10.01.2010, L. Breitkreuz (ZMB); Tuckanarra Hill, 2♂, 16.11.1961, A. Snell (AMS); Urawa Nature Reserve ca 5 km N Mullewa, 28°29.6'S, 115°29.5'E, 1♂, 11.11.2008, V. Ahrens & W. J. Pulawski (CAS); Wydgee Station near Mount Magnet, 2♂, 16.11.1961, A. Snell (AMS). INDONESIA:Bali Island: Dedari, 1♀, 01.01.1948 (BMNH).

Diagnosis.

Sphex corporosus can be distinguished from most other members of the Sphex subtruncatus group through a combination of the following characters: petiole shorter than flagellomere II and pubescence on propodeal enclosure not concealing sculpture. Presence of these traits is sufficient to identify males, while females of Sphex corporosus resemble those of Sphex brevipetiolus . The former, however, has a flat scutellum (Fig. 32B) as well as dark erect setae on the clypeus, whereas in the latter the scutellum is convex and only silvery-white erect setae are present on the clypeus.

Description.

Body black, mandible medially with ferruginous stripe, legs and metasoma dark maroon to black. Wing membrane hyaline, forewing with fuscous spot beyond marginal cell. Wing veins dark orange to dark brown. Appressed pubescence on clypeus and frons as well as erect setae on frons silvery. Pubescence on mesosoma silvery-white. Propodeal enclosure covered with long, erect, silvery-white pubescence, not concealing sculpture. Pubescence denser on posterior end of propodeum.

Female: Body length 27.5-31.8 mm. Apical margin of forewing fuscous beyond submarginal cell III, medial cell II and cubital cell II. Forebasitarsal rake with 10-11 long spines. Free clypeal margin slightly scoop-shaped, clypeus elevated medially above margin. Erect setae on clypeus black. Most of central clypeal area glabrous. Distance between hind- ocelli 0.9 × their shortest distance to compound eyes. Scutum glabrous except for area between admedian lines and lateral and posterior margins. Scutellum flat, sometimes with shallow medial impression. Length of petiole 0.7 × length of flagellomere II. Tomentum moderately dense medially on metasomal tergum I, metasomal tergum II glabrous. Metasomal terga V and VI with few bristles.

Male: Body length 20.3-27.4 mm. Apical margin of forewing nearly hayaline beyond submarginal cell III, medial cell II and cubital cell II. Free clypeal margin truncate, slightly concave towards center. Erect setae on clypeus silvery. Clypeus with narrow medial glabrous stripe which broadens towards free clypeal margin. Distance between hind- ocelli 1.3 × their shortest distance to compound eyes. Pubescence on scutum much denser laterally. Scutellum convex, with medial impression. Length of petiole 0.8 × length of flagellomere II. Metasomal tergum I and anterior half of metasomal tergum II very densely covered with silvery-white tomentum. Metasomal sternum VII with small fringe of dark bristles posterolaterally. Metasomal sternum VIII notched apically, its lateral margin concave.

Variation.

In most of the examined specimens, the metanotum is moderately raised, and in a few with an inconspicuous median impression. A raised metanotum with an impression is usually distinctive for species of the Sphex argentatus group, but since the raising of the metanotum and the depth of the impression in the most extreme known cases of this species are only comparable to the least extreme cases of examined specimens of the Sphex argentatus group, Sphex corporosus is tentatively placed in the Sphex subtruncatus group.

Discussion.

Save for two other species besides Sphex corporosus , all members of the Sphex subtruncatus group have a petiole longer than flagellomere II. One of them, Sphex ermineus , is set apart by having exceptionally long and dense pubescence on the propodeal dorsum. Of the other one, Sphex brevipetiolus , only a single female is known. This specimen differs in a few features from the specimens that have been designated the females of Sphex corporosus , and partially surpasses them in resemblance to the males of Sphex corporosus . Arguments in favor of pairing males and females of Sphex corporosus are addressed in the subsequent paragraph.

The following attributes are shared by Sphex brevipetiolus and males of Sphex corporosus , but not between males and females of the latter: erect setae on clypeus uniformly silvery-white, and scutellum convex and medially impressed. However, the scutellar structure is usually not constant among sexes in the Australian Sphex . On the other hand, Sphex brevipetiolus has several features that differentiate it from both males and females of Sphex corporosus : considerably shorter tomentum on metasomal tergum I, brassy setae on metasomal sterna, and wing veins that are bright orange in the basal half of the wing. For these reasons, males and females of Sphex corporosus are considered to be one species, and Sphex brevipetiolus is treated as a separate one.

Lastly, the geographic range of both sexes is also indicative of the status as a single species, particularly since the number of examined individuals was rather large. Males and females were often found in close proximity to each other, or even in the same areas (Fig. 32C).

Etymology.

Corporosus is a Latin adjective, meaning “corpulent”. A few members of this species from the ANIC were already labeled with this name, although it is unclear by whom. There are no related publications, but the species will be named Sphex corporosus to minimize the risk of confusion in case there are more specimens already so labeled. It undoubtedly refers to the large size of the species.