Asydates irwini ( Howell, 1979 ) Mayor, Adriean J. & Gimmel, Matthew L., 2019

Mayor, Adriean J. & Gimmel, Matthew L., 2019, Revision of the Soft-Winged Flower Beetles of the Genus Asydates Casey, 1895 (Coleoptera: Melyridae: Dasytinae: Listrini), The Coleopterists Bulletin (mo 17) 73, pp. 1-71 : 18-20

publication ID 10.1649/0010-065X-73.mo17.1

publication LSID

persistent identifier

treatment provided by


scientific name

Asydates irwini ( Howell, 1979 )

comb. nov.

6. Asydates irwini ( Howell, 1979) , new combination

( Figs. 3C–D View Fig , 8C–D View Fig , 11E–F, 15E–F, 18A, 22A, 23C, 24E, 28F, 34B, 35C, 37B, 39, 43)

Pristocelis [sic] irwini Howell 1979: 41–43 , 45, fig. 1. Neotype, male, from “Deep Canyon”, CAS type #17130, herein designated. Howell 1997: 13; Mawdsley 2003: 155.

Scelopristis irwini: Mayor 2004: 86 .

Type Material. Neotype ♂ ( Fig. 43 View Fig ), deposited in CAS, labeled, “ Deep Canyon \ Riv. Co. Cal \ x-13 1963 [white printed and hand written label] // M. E. Irwin \Collector [white printed label] //Collected on\ Stephanomeria \pauciflora [white printed and hand written label] //Pogonomyrmex californicus \with captured \ Pristoscelis [white hand written label] // Neotype \irwini \Det. by C. D. Howell [red hand written label] // California Academy \of Sciences \Type No. 17130 [white printed and hand written label] // NEOTYPE \ Pristoscelis \ irwini Howell \des. Mayor & Gimmel 2019 [red printed label]”.

The original holotype of P. irwini was apparently lost, and Howell designated an unpublished “ neotype ”. The following note was found in the A. irwini unit tray in the UCRC collection: “1980: Original Holotype was lost at UCR. A substitute Holotype was sent to Cal. Acad. 1993” [white printed label]; on the reverse, “This note was typed by C. D. Howell” [handwritten by Saul Frommer]. In the CAS collection, there is a male specimen with the label “ Neotype, irwini, Det. by C. D. Howell” [red handwritten label]. However, this neotype designation was never published. In this study, we accept this specimen as neotype with the following added label: “ NEOTYPE Pristoscelis irwini Howell , des. Mayor & Gimmel 2019 ” [red printed label] and consider the neotype, a male, herein designated. This designation is being made to avoid confusion with the closely related A. shoshone , with which it might be confused.

Diagnosis. The robust body, frons with an arched ridge behind epistomal suture, and dense comb of stout black spines along the margin of the pro- and mesotibiae of both sexes distinguish A. irwini from all other species of Asydates .

Redescription. Body broad, robust, shiny ( Figs. 3C–D View Fig , 8C–D View Fig ); microsculpture sparse, inconspicuous on head, pronotum, and elytra. Length 2.7 mm (2.1–3.0 mm, n = 20); width 1.2 mm (0.9–1.4 mm, n = 20). Head, pronotum, and venter black; elytra orange to orange brown with a V-shaped, black macula variable in extent; legs in both sexes and female ventrites 2–5 more or less orange, antennomeres darker, reddish brown. Pubescence dense, reclining, pale, whitish, occasionally golden; pronotal and elytral fringe short, dense. Punctation with punctures fine, indistinct on head and pronotum, slightly larger, more distinct on elytra. Head: Large, narrower than pronotum in both sexes, eyes bulging (Fig. 11E–F); male head 1.37 (1.28–1.47, n = 10), female head 1.49 (1.44–1.53, n = 10) times wider than interocular distance; male head with occipitotemporal region behind eye elongate; male frons with a distinct arched ridge behind epistomal suture. Antennomeres 5–10 weakly serrate; male antennae short, reaching to near middle of pronotum posteriorly, female antennae shorter. Thorax: Pronotum short, wide, 0.69 (0.67–0.73, n = 20) times as long as wide; widest at middle; lateral edges converging to anterior margin, slightly constricted before anterior margin; anterior and posterior angles obsolete, broadly rounded ( Fig. 15E–F View Fig ). Elytra elongate, broadly oval, elytron 3.41 (2.91–4.00, n = 20) times as long as wide, at humeri slightly wider than pronotum; elytral epipleuron distinct at base, becoming obsolete near apex of abdominal ventrite 4 in both sexes; apical margin broadly rounded to sutural angle, inconspicuously serrulate in both sexes. All tibiae with fine, white setae along external margin; pro- and mesotibiae with dense comb of short, stout, black spines arranged along external margin in both sexes ( Fig. 18A View Fig ). Abdomen: Male ventrite 1 with indistinct median patch of whitish setae. Pygidium unmodified, apex broadly rounded in both sexes ( Fig. 22A View Fig ); spiculum gastrale as in Fig. 23C View Fig . Median lobe of aedeagus a bowed tube with apex bent slightly ventrally ( Fig. 24E View Fig ); tegmen very short and wide, without constriction at base of ring ( Fig. 28F View Fig ).

Host Plant Associations. Adults of A. irwini have been collected from flowers of plants in the families Asteraceae [ Isocoma acradenia (1), Palafoxia linearis (3), Stephanomeria pauciflora (203) ( Figs. 34B View Fig , 35C View Fig ), and Stephanomeria sp. (1)], Polygonaceae [ Eriogonum sp. (2)], and Zygophyllaceae [ Larrea tridentata (4)].

Seasonal Distribution. 25 August to 7 December ( Fig. 39 View Fig ).

Geographic Distribution. Deserts and desert margins of Kern County south to Imperial County , California, east to northwestern Arizona and southwestern Utah ( Fig. 37B View Fig ) .

Material Examined. Records reported here are based on the examination of 255 specimens. USA: ARIZONA: Mohave County: Virgin River Canyon Recreation Area, 23 September, 1986, Baumann & Nelson (1♂, 2♀♀, BYU, 1♂, 1♀, UCRC). CALIFORNIA: Imperial County : 12 miles So. of Ocotillo, on Stephanomeria pauciflora / Timberlake Coll., Nov. 12 ‘39 (1♀, UCRC) ; Kern County: 7.5 mi. S. Inyokern on Co. Rd. , 5- x-1985, G. H. Nelson, on yellow composite (1♀, UCRC) ; Oak Creek Rd., W. of Mojave , elev. 1,170 m, N35°03’05.9”, W118°19’47.2”, 1 Sept. 2016, A. J. Mayor, collected beating flowers of Stephanomeria pauciflora (15♂♂, 9♀♀, UCRC, 1♂, 1♀, SBMNH) GoogleMaps ; Los Angeles County: Bob’ s Gap Rd. , W. of Bob’ s Gap ; elev. 1182 m, N34°26’57.2”, W117°49’52.3”, 7 Sept. 2016, A. J. Mayor, collected beating flowers of Stephanomeria pauciflora (10♂♂, 16♀♀, UCRC, 1♂, 1♀, SBMNH) GoogleMaps ; 4 mi. N. Lancaster, ix-9-1962, John T. Doyen (3♂♂, 1♀, EMEC) ; Pallett Creek Rd. W. of Big Rock Creek , elev. 1,087 m, N34°27’33.9”, W117°52’12.6”, 7 Sept. 2016, A. J. Mayor, collected beating flowers of Stephanomeria pauciflora (20♂♂, 19♀♀, UCRC) GoogleMaps . Riverside County: Coyote Creek , x-15-1963, M. E. Irwin Collector (7♂♂, 9♀♀, UCRC) ; same except Stephanomeria (1♀, UCRC) ; same except Palafoxia linearis (1♂, UCRC) ; Coyote Creek Basin, x-15-1963, M. E. Irwin collector, collected on Palafoxia linearis (1♂, 1♀, UCRC) ; Deep Canyon , x-13-1963, M. E. Irwin collector, on Hiptus [sic] twig, +/- 60 ft. from host plant (1♂, UCRC) ; same except xi-12- 1963, M. E. Irwin collector, on Stephanomeria pauciflora (3♂♂, 2♀♀, UCRC) ; same except x-15-1963 (3♀♀, UCRC) ; Deep Cyn. , ix-10-64, E. I. Schlinger (1♂, 1♀, UCRC) ; 4 miles west Desert Center, Sp. 16, ’61, on Stephanomeria pauciflora, Timberlake Coll. (1♀, UCRC) , Pleasant Valley , x- 29-1963, E. I. Schlinger collector, on Stephanomeria sp. (1♀, UCRC) ; P. L. Boyd Desert Research Center, 3.5 mi. S. Palm Desert, 9 Oct. 1963, Schlinger, Irwin (4♂♂, 2♀♀, UCRC) ; same except 17-xii-63, M. E. Irwin (1♂, UCRC) ; same except x-13-1969, no collector (1♂, UCRC) ; same except 30-xi-63, M. E. Irwin, on Stephanomeria pauciflora (3♂♂, 1♀, UCRC) ; same except Coyote Creek , 15-x-63, E. I. Schlinger, on Eriogonum (2♀♀, UCRC) ; same except S. Palm Desert, Coyote Creek , 15 x-1963, M. Irwin (1♂, 1♀, UCRC) ; same except S. Palm Desert , 9-x-63, coll. Schlinger, Irwin, on Stephanomeria pauciflora (1♂, 1♀, UCRC) ; Whitewater Canyon, S. of Whitewater Preserve , elev. 561 m, N33°57’35.5”, W116°38’56.4”, 28 August 2016, A. J. Mayor, collected beating flowers of Stephanomeria pauciflora (12♂♂, 16♀♀, UCRC, 1♂, 1♀, SBMNH) GoogleMaps ; San Bernardino County: Kelbaker Rd nr Granite Mts overlook, 34.80521° -115.61078°, 1,210 m, 5 October 2018, ex Stephanomeria pauciflora , M. & L. Gimmel, ML308 (1♂, 1♀, SBMNH) ; Oro Grande, Sp. 14 ’35, on Isocoma acradenia, Timberlake Coll. (1♂, UCRC) ; San Bernardino Natl. Forest, Hwy. 18, S. of Lucerne Valley , elev. 1,430 m, N34°20’56.4”, W116°50’44.9”, 25 August 2016, A. J. Mayor, collected beating flowers of Stephanomeria pauciflora (16♂♂, 16♀♀, UCRC, 1♂, 1♀, SBMNH) GoogleMaps ; S. of Lucerne Valley on Hwy. 18, elev. 1,392 m, N34°20’58.9”, W116°50’45.1”, 24 August 2018, A. J. Mayor, collected beating flowers of Stephanomeria pauciflora (22♂♂, 6♀♀, UCRC) GoogleMaps . UTAH: Washington County: Beaver Dam Well , 28 September 1985, on Larrea , Nelson & Mower (3♂♂, 1♀, BYU) ; 3 miles southwest of Shivwits Indian Reservation , 9 September 1959, Andrew H. Barnum (2♂♂, 1♀, BYU) ; 3 miles south of Welcome Spring , 37°03.6’N, 113°55.2’W, 23 September 2011, S.M. Clark (1♂, 2♀♀, BYU, 1♂, 1♀, UCRC) .

Remarks. The elytral color is variable in A. irwini . The dark, V-shaped marking on the elytra varies from restricted to the basal quarter or less, leaving most of the elytra orange, to so extensive as to leave only the margins and apex of the elytra orange. This color variation does not appear to be sex linked or to have a geographic component.

The arched ridge on the frons behind the epistomal suture is the “frontal cord” of Howell (1979, fig. 1C). This unique structure of the frons is also found in males of A. shoshone in which it is less well developed.


California Academy of Sciences


University of California, Riverside


Monte L. Bean Life Science Museum


Santa Barbara Museum of Natural History


Essig Museum of Entomology














Asydates irwini ( Howell, 1979 )

Mayor, Adriean J. & Gimmel, Matthew L. 2019

[sic] irwini

Mawdsley 2003: 155
Howell 1997: 13
Howell 1979: 43
Darwin Core Archive (for parent article) View in SIBiLS Plain XML RDF