Enneboeus marmoratus Champion, 1893

Gimmel, Matthew L., Johnston, M. Andrew & Merkl, Ottó, 2018, Enneboeus marmoratus Champion New to the USA, with a World Catalog of the Family Archeocrypticidae (Coleoptera: Tenebrionoidea), The Coleopterists Bulletin 72 (2), pp. 269-278 : 271

Enneboeus marmoratus Champion, 1893 ( Figs. 1–6 )

Material Examined. USA [new country record]: CALIFORNIA: San Francisco Co.: San Francisco, Noe Valley , 37.74522°, -122.43047°, at lights at night, 26 Sep 2017, leg. K. R . Schneider (2 males, SBMNH); same data except 15 Oct 2017 (1 male, HNHM) .

Diagnosis. This species can be recognized among the members of Enneboeus Waterhouse by its large size (ca. 3.5–4.0 mm, one of the largest known members of the family), distinctive undulating setal pattern on the elytra, and elytra lacking distinct striae (rows of punctures extremely faint) ( Figs. 1, 3 ). Additionally, males possess a sex patch (small, round pit containing setae) medially on the prosternum near the anterior margin (visible in Fig. 2 ). The aedeagus ( Figs. 4, 5 ) has a distinctive shape, particularly the parameres, which have a medially directed tooth subapically and a compact tuft of setae ventrally.

Notes. The original posts on BugGuide from Ken R. Schneider may be found at <bugguide.net/node/ view/1433463> and <bugguide.net/node/view/ 1446701>. The first post shows a specimen ( Fig. 6 ) from 31 August 2017, which is unvouchered. The second post shows one of the specimens from 26 September 2017, now vouchered at SBMNH. A third post, on iNaturalist (<inaturalist.org/observations/ 7873839>) shows a specimen active on 10 September 2017, while a fourth post (<inaturalist.org/ observations/8423488>) shows the specimen from 15 October 2017, now vouchered at HNHM. All were observed on the lighted balcony of a single urban residence, noted above in the Material Examined section.

This species was originally described from “Jalapa and Misantla” in Veracruz, Mexico, though it was only based on a single female specimen (Champion 1893). Subsequently, Merkl (1988) reported 17 additional specimens from various localities in Mexico, including the states of Hidalgo, México, Oaxaca, Puebla, Querétaro, and San Luis Potos´ı. As such, its presence in central San Francisco , California is quite surprising .

Almost nothing is known about the biology of this species. Most of the specimens reported by Merkl (1988) were collected at fairly high elevation (1,200 –2,500 m) through Berlese extraction of leaf litter, although one was collected “on gilled mushroom”. The male sex patch presumably produces an attractant pheromone ( Faustini and Halstead 1982) and is very similar in size, position, and shape to the sex patch of Pseudotriphyllus Reitter (Mycetophagidae) ( Carlton and Leschen 2009). Whether saprophagous or mycophagous, the beetles have an apparent predilection for moist organic debris, a habit shared with the eastern Enneboeus caseyi Kaszab ( Triplehorn and Wheeler 1979) , which indicates that they could potentially have been transported in potted plants, possibly as larvae or pupae. The beetles were collected on unusually warm days for the region, with the reported highs in San Francisco on the collection dates being 30° C, 32° C, 31° C, and 27° C, respectively (NOAA Climate Data Online, <ncdc.noaa.gov/cdo-web>). The fact that a number of specimens were observed over the span of about a month and a half suggests establishment in the area. Since winters in the area are quite mild, almost never reaching 0° C, the possibility of the species’ persistence in the area is not unlikely.

Figures

Figs. 1–5. Enneboeus marmoratus, specimen from San Francisco, California, USA (SBMNH). 1) Dorsal habitus;

Fig. 6. Enneboeus marmoratus, photograph of first observed live specimen in San Francisco, California, USA, on 31 August 2017 (specimen unvouchered). Photograph by Ken R. Schneider.