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

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

( Figs. 3C–D , 8C–D , 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 ), 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The original holotype of P. irwini was apparently lost, and Howell designated an unpublished “ neotype ”.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 , 8C–D ); 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 ). 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 ). Abdomen: Male ventrite 1 with indistinct median patch of whitish setae. Pygidium unmodified, apex broadly rounded in both sexes ( Fig. 22A ); spiculum gastrale as in Fig. 23C . Median lobe of aedeagus a bowed tube with apex bent slightly ventrally ( Fig. 24E ); tegmen very short and wide, without constriction at base of ring ( Fig. 28F ).

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 , 35C ), and Stephanomeria sp. (1)], Polygonaceae [ Eriogonum sp. (2)], and Zygophyllaceae [ Larrea tridentata (4)].

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

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

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) ; 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) ; 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) . 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) ; 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) ; 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) . 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.

Figures

Fig. 3. Asydates species, dorsal habitus. A. tongva: A) Male, B) Female. A. irwini: C) Male, D) Female. Scale

Fig. 8. Asydates species, lateral habitus. A. tongva: A) Male, B) Female. A. irwini: C) Male, D) Female. A. shoshone: E) Male, F) Female; A. ruficauda: G) Male, H) Female. Scale bars = 1.0 mm.

Fig. 43. Pristocelis [sic] irwini (= Asydates irwini), neotype male, dorsal, left lateral, and frontal habitus, head

Fig. 15. Asydates species, pronota. A. chumash: A) Male, B) Female. A. tongva: C) Male, D) Female. A. irwini:

Fig. 18. Asydates species, dorsal view of male protibia. A) A. irwini, B) A. shoshone, C) A. washoe.

Fig. 22. Asydates species, male pygidium and attached abdominal sternite VIII, ventral view. A) A. irwini, B) A. ruficauda, C) A. vandykei (spiculum gastrale is still attached), D) A. inexpectatus. Scale bars = 0.5 mm.

Fig. 23. Asydates species, spiculum gastrale. A) A. grandiceps, B) A. rufiventris, C) A. irwini. Scale bars = 0.5 mm.

Fig. 24. Asydates species, median lobe of aedeagus, right lateral view. A) A. grandiceps, CA: Los Angeles Co.: Franklin Canyon, B) A. grandiceps, CA: San Bernardino Co.: Lone Pine Canyon, C) A. kumeyaay, Mexico: Baja California: Agua Caliente, D) A. kumeyaay, CA: San Diego Co.: Otay Lakes Road, E) A. irwini, CA: San Bernardino Co.: south of Lucerne Valley on Highway 18, F) A. shoshone, NV: Elko County: 43.5 km south of Wells. Scale bars = 0.5 mm.

Fig. 28. Asydates species, tegmen of aedeagus (apex directed upward). A) A. grandiceps, CA: San Bernardino Co.: Lone Pine Canyon, B) A. kumeyaay, Mexico: Baja California: Agua Caliente, C) A. rufiventris, CA: Los Angeles Co.: Mount Baldy Road, D) A. chumash, CA: Kern Co.: Mount Pinos, E) A. tongva, CA: San Bernardino Co.: Middle Fork Lytle Creek, F) A. irwini, CA: San Bernardino Co.: south of Lucerne Valley on Highway 18. Scale bars = 0.5 mm.

Fig. 34. Stephanomeria pauciflora, flower host for Asydates species. A) Specimen growing in CA: San Bernardino County: Middle Fork Lytle Creek, from which A. tongva was collected. Photograph taken 25 July 2017 by Adriean J. Mayor. B) Specimen growing in CA: San Bernardino Co.: Kelbaker Road near Granite Mountains Overlook, from which A. irwini was collected. Photograph taken 5 October 2018 by Matthew L. Gimmel.

Fig. 35. Live Asydates species on flower hosts. A) A. rufiventris pair on flower head of Stephanomeria pauciflora, CA: Los Angeles County: Bob’s Gap. Photograph taken 28 July 2016 by Adriean J. Mayor. B) A. cf. rufiventris congregating on flower head of Stephanomeria cichoriacea, CA: Kern County: Tejon Ranch. Photograph© taken 8 September 2014 by Neal Kramer. C) A. irwini male on flower head of S. pauciflora, CA: San Bernardino County: Afton Canyon. Photograph taken 7 October 2014 by John Doyen.

Fig. 39. Seasonalities of adult Asydates species, by month, based on collection records in the Material Examined sections.

Fig. 37. Distribution of Asydates species. A) Localities of examined specimens of A. rufiventris (black dots), A. chumash (green squares), and A. tongva (yellow stars), B) Localities of examined specimens of A. irwini (black dots), A. washoe (yellow stars), A. shoshone (red triangles), and A. phantasma (blue squares).