Pleocoma callisto Marshall, 2018

Marshall, Christopher J., 2018, Two new species of rain beetle (Coleoptera: Pleocomidae: Pleocoma Le Conte, 1856) in the Pacific Northwest of the United State of America, Zootaxa 4471 (2), pp. 387-395 : 392-393

Pleocoma callisto Marshall , new species

Figures 1–2 .

Type material. Holotype: OSAC _0000188049, pinned, adult male, labeled “ USA: Oregon, Hood River Co., ½ mile east of Oak Grove ; D. Pierson orchard, 7 November 1956, Ellertson & Kardos ”. With determination label as follows: P. crinita Linsley by F. E. Ellertson 1959. Deposited at the Oregon State Arthropod Collection, Corvallis, Oregon .

Type locality. United States of America, Oregon, Hood River County, Oak Grove in vicinity of 45.661°N, 121.578°W ( Fig. 5 )

Paratypes. Nine males and one female. “ USA: Oregon, Hood River Co., ½ mile east of Oak Grove; D. Pierson orchard , 7 November 1956, Ellertson & Kardos” // det. P. crinita Linsley by F. E. Ellertson 1959: (one female: OSAC _0000188079, five males: OSAC _0000188047, OSAC _0000188048, OSAC _0000188050, OSAC _0000188052, OSAC _0000188054); “ USA: Oregon, Hood River Co., ¾ mile east of Oak Grove ; B. Hukari Orchard , 7 November 1956, Ellertson & Kardos” // det. P. crinita Linsley by F. E. Ellertson 1959 (two males: OSAC _0000188053, OSAC _0000188055); “ USA: Oregon, Hood River Co. 1/ 8 mile west of Oak Grove ; McCurdy orchard . 26 November 1957. F. E. Ellerton ” //det. P. crinita Linsley by F. E. Ellertson 1959 (one male: Canadian Museum of Nature , Ottawa: CMNEN 00029539 ); “USA: Oregon, Hood River Co., Oak Grove, NW, NE Sec 17 T2N/R10E 10 December 1973, blacklight trap, leg. G. Fields, R. Penrose, R. Westcott & R. Zwick ” (one male: CMNEN 00029540 ). Paratypes deposited in Oregon State Arthropod Collection ( OSAC) and Canadian Museum of Nature , Ottawa, Ontario, Canada ( CMNEN) .

Other material. Over 150 specimens of P. callisto (including series of both males and females) were examined, all from the general vicinity of Hood River, Oregon. The precise locations and collecting dates can be obtained from the publications of Linsley (1956) and Ellertson (1958). Specimens of P. callisto (determined as P. crinita) are relatively common in research collections because the Hood River populations were sampled in large numbers and widely shared among collectors.

Diagnosis. This species may be separated from all other known Pleocoma by the following combination of characters: male scutellum densely setose, 7-antennomere antennal club, male pronotum covered in long golden setae, with denser setae along midline from anterior edge to posterior edge. Color of male generally caramel brown (lighter than in P. laker and P. minor); often subtly bicolored with prontum slightly lighter than elytra, unlike P. oregonensis, P. simi Davis, 1935, or P. dubitalis leachi Linsley, 1938, which are strikingly bicolored.

Description. Male: habitus rounded, oval, reddish caramel brown; length between 22–25 mm from frontoclypeal horns to median apex of elytra (holotype: 24 mm); covered (except for posterior dorsal areas of elytra) in long golden pubescence, particularly on ventral surface and scutellum. Head: similar to P. laker but with finer and denser punctation and setation.

Thorax: protonotum with dense fine setation over entire surface; medial longitudinal groove complete and with setation for entire length.

Female. larger than male (28–31 mm), evenly rufous-brown; with short, golden setae, shorter and less dense than in male. Pronotum heavily punctate, median longitudinal groove distinctly more densely setose.

Distribution. This species is known from the vicinity of Hood River, Oak Grove, and Odell Oregon. Occasional males have been collected at lights at lower elevations near the river (~ 50 m) but the vast majority of specimens, and all females, are known from higher sites around 200– 300 m. Today, planted fruit orchards occupied much of the range of this species; however, patches of mixed ponderosa pine and Garry oak can be found that likely reflect the original habitat.

Natural history. Mating flights of the males commence in the fall, typically in September or October and continue into November with scattered observations in December and early January. The natural history of this species, including development and seasonal phenology, has been substantially studied under the name P. crinita (Linsley 1956; Ellertson 1958).

Etymology. In keeping with the previous epithet, this species with distinctly long setae is named in honor of another faithful canine companion: Callisto, a long-coated briard ( Fig. 6B) that has spent a great many chilly mornings alongside the author in search of rain beetles. This name should be treated as a noun in apposition.

Figures

FIGURE 1. Habitus photographs of exemplar specimens (not type material). Males: A, Pleocoma laker Marshall, new species; B, P. callisto Marshall, new species. Females: C, P. laker Marshall new species; D, P. callisto Marshall new species.

FIGURE 2. Head and pronotum, male dorsal; A, P. laker Marshall new species; B, P. callisto Marshall, new species; C, P. crinita Linsley, 1938 paratype; D, P. crinita Linsley, 1938 paratype labels

FIGURE 5. Type localities for Plecooma species in the vicinity of the Columbia River. Green circle: Pleocoma dubitabilis dubitabilis (Oregon, Forest Grove/Dilley); black hexagon: Pleocoma dubitabilis leachi (Oregon, Colton); red star: Pleocoma callisto (Oregon, Hood River, vicinity Oak Grove); yellow circle: Pleocoma minor (Oregon, Hood River); white circle: Pleocoma crinita (Washington, Glenwood); white square: Pleocoma oregonensis (Oregon, The Dalles); yellow star: Pleocoma laker (Washington, NW of Goldendale).