Stethophotopsis maculata Pitts

Stethophotopsis maculata Pitts in Pitts & McHugh, 2000, ♂ ♀

( Figs 270–282 View FIGURES 270–278 View FIGURES 279–283 )

Stethophotopsis maculata Pitts in Pitts & McHugh, 2000: 31. Holotype male: USA, Arizona, Brown Canyon, Baboquivari Mountains, 6.IX.1958, Stange and Menke (LACM), examined.

Stethophotopsis maculata : Pitts & Manley 2002: 674. Female description.

Diagnosis. FEMALE. As for genus. Body length 6.5–9 mm. MALE. As for genus. Body length 7–10 mm.

Material examined. MEXICO, Sinaloa, Los Mochis , VI.1922 ( 1 ♀ CASC) ; USA, Arizona, Cochise Co. : Mescal Road , 2.8 mi N I-10, 32.002 -110.433, 15–24.VIII.2023, LED pitfall trap, K. Williams and A. Nguyen ( 1♂ 1♀, CSCA) GoogleMaps ; San Pedro River , near Highway 90, 7 mi. E Sierra Vista, 6.VIII.2024, Yunfan Zhang ( 3♀ 1♂, YZPC) .

Distribution. Mexico: Sinaloa and Sonora; USA: Arizona.

Remarks. Until recently, the preferred habitat and distribution of St. maculata was poorly understood. The two specimens from Arizona are from imprecise localities that span numerous microhabitats ( Pitts & McHugh 2000). Brown Canyon Road in Santa Cruz County , Arizona spans over 10 km and rises from roughly 1000 m in elevation to 1450 m. Madera Canyon spans an elevational range of 1200 m to 1700 m in about 5 km. Both sites feature numerous differences in soil type, plant assemblages, vegetative density, and microhabitat. In August 2023, KAW collected one male and one female specimen in a pitfall trap from near Mescal, Arizona. These are the first recorded specimens from a precise georeferenced locality and the northernmost records for this genus and species. They came from an open habitat dominated by sparse short mesquite trees and bunch grasses with predominantly decomposed granite soil ( Fig. 283 View FIGURES 279–283 ); the elevation at the site was 1240 m. Future efforts to collect Stethophotopsis in Madera Canyon or Brown Canyon would likely bear more results in sparsely vegetated habitats at lower elevations.

Although this genus belongs to the nocturnal velvet ant tribe, it has been presumed to be diurnal because of the bright coloration. Until now, the only known specimens either did not mention a collecting method or were collected with passive methods. The pitfall traps used to collect the aforementioned recent specimens ( Fig. 283 View FIGURES 279–283 ) were equipped with a solar LED light, so they collect both diurnal and nocturnal mutillids. In another recent collecting event in 2024, YZ observed and collected a series of St. maculata near the San Pedro River , east of Sierra Vista, Arizona. Multiple females were observed during daylight in the afternoon along with other diurnal species, including Dasymutilla foxi (Cockerell) , D. eminenti a Mickel, D. gloriosa (Saussure) , and Pseudomethoca praeclara (Blake) . A single male was also collected around the base of a bush at the same time window. The locality of this series was separate from the riparian habitat of San Pedro River , in open shrubland at approximately 1235 m of elevation. The discovery of these specimens actively walking in daylight along with other diurnal species reveals that the species is diurnal, rather than its nocturnal relatives.