Platyceroides (Platyceroides) pacificus (Casey), revised status

Platycerus pacificus Casey, 1889: 165, original combination.

Type series. Lectotype male of P. pacificus (USNM), here designated, labeled: a) handwritten “ pacificus / Csy.”; b) “CASEY / bequest / 1925”; c) on orange paper, “TYPE USNM / [36210]”; d) “ Platyceroides pacificus / (Casey, 1889) / det. M.J. Paulsen 2016”; e) on red paper, “ Platycerus / pacificus Casey / Lectotype / det. MJ Paulsen”.

Taxonomy. Casey (1889) reported examining three specimens, but only one is present in the USNM collection, and I designate it as the lectotype. It has male genitalia that are barely discernible from those of P. agassii . However, it has a much larger antennal club, is darker in coloration and has more robust metatibiae (Fig.

4A). Additional specimens matching the holotype appear to be allopatric with P. agassii and are distributed at much higher elevations (most specimens examined are from ~ 2000 m) and farther inland, north of the Eel River in California (Fig. 25). I considered treating P. pacificus a subspecies of P. agassii, because there is far less variation between the male genitalia of the two taxa than is usually present between Platyceroides species. However, there are slight differences in the simple flagellum, with the enlarged portion of the apex smaller and with a shorter median process (Fig. 4 B). In combination with the allopatry, distinctly larger antennal club, and other the morphological differences it seems more straightforward to treat the taxon as distinct.

Distribution (Fig. 25). CALIFORNIA: COLUSA: No locality. GLENN: Telephone Camp. HUMBOLDT: Dinsmore; Iaqua; Mountains near Korbel; Larabee Valley. LAKE: Hullville. MENDOCINO: Covelo; Leech Lake. SISKIYOU: Copper Creek; El Capitan. TRINITY: no locality.

Remarks. Specimens of P. pacificus typically have elytra with a shiny appearance but vary from glossy to weakly micropunctate under high magnification. However, the two P. pacificus specimens seen from Trinity County, California, have distinct microsculpture and appear slightly opaque. Among coastal species such sculpturing is otherwise confined to the P. pampinatus species group. Because of this, genitalic dissection is the best method of verifying and identification.