Sphaeropthalma triangularis (Blake)

Pitts, James P., Wilson, Joseph S., Williams, Kevin A. & Boehme, Nicole F., 2009, Velvet ants (Hymenoptera: Mutillidae) of the Algodones sand dunes of California, USA, Zootaxa 2131, pp. 1-53 : 45-46

Sphaeropthalma triangularis (Blake)

Agama triangularis Blake, 1871 . Amer. Ent. Soc., Trans. 3: 262. Male. Holotype data: Nevada (ANSP).

Diagnosis of male. The male of this species is easily recognized by the lobe-like projections on the hind coxae. Other useful characters include the triangular shaped posterior margin of the head (Fig. 94), the weakly excised mandible, the lack of mesosternal processes, and the unique triangulate posterior projection of the apex of the hind tibia (Fig. 96). The genitalia are illustrated in Fig. 26 .

Diagnosis of female. The female of this species has the following combination characters: the dorsum of the body is covered with sparse erect brachyplumose setae (Figs. 85–87), but the integument is not obscured; the ventral margin of the mandible has a slight excision ( Fig. 40 ); the head below eyes is parallel (Fig. 85); the head evenly rounded in lateral view (Fig. 85); the first metasomal segment is sessile with the second segment (Fig. 86); and the pygidium is longitudinally striate.

Description of female: Coloration and Setal Pattern. Body testaceous (Figs. 85–87). Legs and flagellum lighter. Sparse white brachyplumose setae throughout. Metasomal segments with sparse to moderate fringe of white plumose setae. Legs with white brachyplumose setae.

Head. Head rounded posteriorly (Fig. 85), not as wide as mesosoma, moderately punctate. Eye ovate (Fig. 86), distance from posterior mandibular articulation ~ 2X visible length of pedicel. Clypeus protruding anteriorly, posteromedially produced into low triangular tubercle. Antennal scrobe with dorsal carina. Antennal tubercle glabrous. Flagellomere I ~1.75X length of pedicel. Flagellomeres II–III ~1.2–1.4X length of pedicel. Mandible bidentate apically ( Fig. 40 ). Ventral mandibular margin with slight excision subtended by angulate basal tooth ( Fig. 40 ). Genal carina absent.

Mesosoma. Mesosoma slightly wider anteriorly than posteriorly, longer than broad (Fig. 87). Mesosoma densely punctate on dorsum. Propleuron anteriorly, mesopleuron medially running vertically, and lateral margin of propodeum with extreme ventral region punctate. Humeral angle dentate. Scutellar scale absent. Mesosternum with low transverse tubercle present medially just anterior to mesocoxa. Metasternum tridentate. Propodeum with distinct dorsal and vertical faces.

Metasoma. Segment 1 distinctly sessile with segment 2 (Fig. 86). T1 with small sparse punctures. T2 with dense shallow punctures anteriorly. T2 with felt line, 0.25X length of tergite. T3–5 shagreened. T6 with distinct pygidial area defined by weak carinae; surface strongly densely longitudinally striate; apex rounded. S2–5 with punctation similar to tergites.

Length. ~ 11–13 mm.

Material examined. California, Imperial Co. : Algodones dunes, 7 mi. SE Glamis, 32°55’20”N 114°59’14”W, 1 female, 19.Mar.1979 – 24.Mar.1979 ( CDFA); Algodones Dunes, Coachella Canal Road, 6.4 km NW Hwy 78, 14.4 km NW Glamis, 1 male, 24–28.Mar.2008, Museum Survey Team ( UCDC).

DNA voucher specimen data. Arizona, Cochise Co. : San Pedro Riparian Natl. Cons. Area, 2 males, JP108, JP111 ( EMUS); Willcox playa, 1 male, 21.Jun.2005, Williams, Pilgrim and Pitts, JP299 ( EMUS). Utah, Garfield Co., Alvey Wash, 5 km S Escalante, 2 females, 24–25.May.2002, M.E. Irwin and F.D. Parker, JP185, JP343 ( EMUS).

Distribution. Southwestern USA.

Remarks. While the genetic distance for ITS2 is higher for this species than the majority of the other species treated in this paper (Table 1), the intersexual distance for ITS2 is much less than the interspecific genetic distance ( Table 5). This species is widespread and seems to be rare on the Algodones Sand Dunes.

This species was placed in its own species-group by Schuster (1958). Sphaeropthalma triangularis , however, belongs in Schuster’s S. rustica species-group based on male morphology and is closely related to S. unicolor and S. angulifera Schuster. They share similarities in mandibular morphology (a weak ventral excision along with an oblique apex), distinct ventral felt lines, and similarities in genitalic morphology.

Figures

FIGURES 23 – 30. 23 – 26 Genitalia, dorsal view left, ventral right. 23. Sphaeropthalma blakeii; 24. S. ecarinata; 25. S. militaris; 26. S. triangularis; 27. Dorsal view of Odontophotopsis villosa, female; 28. Anterior view of head of O. villosa, female; 29. Anterior view of head of O. biramosa, male; and 28. Anterior view of head of O. sonora, male.

FIGURES 31 – 46. Lateral view of mandible, 31 – 40 female and 41 – 46 male. 31. O. arcuata; 32. O. inconspicua; 33. O. melicausa; 34. O. obscura; 35. O. parva; 36. O. villosa; 37. Sphaeropthalma blakeii; 38. S. difficilis; 39. S. militaris; 40. S. triangularis; 41. O. ambigua; 42. O. arcuata; 43. O. aufidia; 44. O. melicausa; 45. O. becki; and 46. O. django.