Hylurgops porosus ( LeConte, 1868 )

Mercado-Vélez, Javier E. & Negrón, José F., 2014, Revision of the new world species of Hylurgops LeConte, 1876 with the description of a new genus in the Hylastini (Coleoptera: Scolytinae) and comments on some Palearctic species, Zootaxa 3785 (3), pp. 301-342 : 333-335

Hylurgops porosus ( LeConte, 1868)

( Figures 7 i, 15i, 17i, 22b, 23, 24b)

Hylastes porosus LeConte, 1868:175 (Cayo de los Reyes, CA, USA) H. (Hylastes) porosus, Hagedorn, 1910:46

Hylurgops lecontei Swaine, 1917:16 (Colorado, USA) Synonymy: Wood, 1971c:147

Diagnosis. Hylurgops porosus is distinguished from the similar and sympatric H. reticulatus at high (> 50×) magnification by the incomplete reticulate surface of the elytra ( Fig. 22 b) and by lacking the ventral lobe of the aedeagus ( Fig. 7 i). It can be distinguished from H. knausi in the extreme southern limit of its distribution by the by the marked difference between the small and large pronotal punctures clearly distinct different-sized pronotal punctures ( Fig. 17 i) and the long ventral hair-like setae. It can be distinguished from dark specimens of H. pinifex by its narrower body and the indistinct pronotal constriction ( Fig. 17 i).

Description. Size. Length 3.5–4.5 (avg. 4.0 ± 0.3) mm long, 2.7× longer than wide. Color. Mature adult black or brownish red to bicolored with black pronotum or reddish-brown and reddish-brown or brownish elytra, ventral sclerites brown to black with tarsi dark reddish-brown. Frons. Transverse impression moderately impressed; a shiny carina extends from lower convex area on lower frons to epistoma; vestiture consisting of hair-like setae, longer below middle, 2–7× a frontal puncture diameter’s length. Pronotum. Slightly elongate 0.9–1.1 (1.0 ± 0) ( Fig. 17 i), its base narrower than elytra, smoothly tapering anteriorly, widest near middle; slightly raised middle line extends across the entire length, surface shiny to variably reticulate; discal punctures of two sizes, smaller more abundant, larger 3× diameter of smaller, inner surface shiny or reticulate, margin smooth to reticulate; vestiture sparse to absent on disc, short, recumbent hair-like setae, averaging the length of larger punctures on disc, 2× longer on marginal areas; basal ⅓ of lateral margin narrowly rounded becoming broadly rounded anteriorly to slight anterior constriction. Elytra. Anterior margin near straight; strial punctures vary from round to keyholeshaped ( Fig. 12 ), shallowly concave, surface smooth ( Fig. 22 b), separated by half their diameter at disc; interstriae smooth, slightly wider than discal striae, minutely punctured (>100× or more), each with a short, recumbent hairlike setae on anterior two thirds of disc, with a single row of erect hair-like setae from behind a punctate granule, as long as discal puncture width on last third, 1.5× strial puncture diameter apart. Declivity. Striae slightly impressed, half as wide as interstriae, punctures round, deep, smaller than on disc, 0.75× diameter apart, second interstriae slightly impressed, all with granules separated by 1.5× puncture length, each with an erect, yellowish hair-like seta as long to slightly longer than interstriae width. Ventral sclerites. Surface reticulate; ground vestiture of distinct long hair-like setae. Legs. Protibiae with two large socketed teeth before apical angle; meso- and metatibiae with one or two large socketed teeth before apical angle; third tarsal segment slightly broader than second. Aedeagus. Lacking a ventral lobe ( Fig. 7 i).

Male. Fifth ventrite with a small dense patch of setae medially on posterior margin.

Gallery: A uniramous, longitudinal gallery ( Hopkins 1902) in the lower bole and roots.

Material examined. 93 specimens. CANADA. Alberta: Banff ( CNCI), Cypress Hills ( CNCI), Laggan ( CNCI), Lake Louise ( CNCI). British Columbia: Atlin ( CNCI), Cawston ( CNCI), Chicoltin ( CNCI), Creston ( CNCI), Creston, Summit Creek ( CNCI), Enderby ( CNCI), Golden ( CNCI), Kingsvale ( CNCI), Kleena kleene, “Tatler lake” ( CNCI), Lorna ( CNCI), Manning Provincial Park ( CNCI), Merritt: Cranbrook ( CNCI), Midday Valley ( CNCI), Newgate ( CNCI), Peachland ( CNCI), Summerland ( CNCI), Trepanier Creek ( CNCI), Trinity Valley ( CNCI), Vermillion “Summit” Pass, Banff Rd. ( CNCI), Vernon ( CNCI). Saskatchewan: Cypress Hills ( CNCI). USA. Arizona: Apache Co.: Chuska Mountains ( CNCI). California: Alameda Co.: Berkely ( CNCI), Piedmont ( CSUC); Alpine Co.: Sand Flat ( CSUC); El Dorado Co.: Grass Lake, Tahoe ( CNCI); Lake Co.: Cobb ( DEBC); Lassen Co.: Lassen NF ( CNCI, DEBC); Madera Co.: Northfork ( CNCI); Mariposa Co.: Yosemite ( CSUC); Marin Co.: Inverness ( DEBC); Modoc Co.: Willow Ranch ( DEBC); Nevada Co.: Truckee ( CNCI); Plumas Co.: Chester ( CNCI); Tuolumne Co.: Avalanche Meadows at Sequoia NP ( CNCI). Colorado: Adams Co.: JCK Corp. Henderson ( CSUC); Archuleta Co.: Fairfield ( CSUC); Boulder Co.: Gold Hill ( CSUC), Meeker Park ( DEBC); Chaffee Co.: 17 km W Buena Vista ( CSUC), Custer Rd 306 2 mi. S Rd 307, Droney Gulch ( CSUC); Denver Co.: Denver ( CSUC); El Paso Co.: Black Forest ( CSUC); Fremont Co.: 5 mi. N Cotopaxi ( CSUC), US 285 W Aspen Park ( CSUC); Grand Co.: Fraser Exp. For. ( CSUC); Gunnison Co.: Agate Camp. 6 mi. W Monarch Pass. ( DEBC); Jackson Co.: Cameron Pass ( CSUC), CO St. Forest ( CSUC); Larimer Co.: Buckhorn Cny. ( DEBC); Estes Park ( CSUC), Estes Park, Timber Creek Camp. ( CNCI), Fort Collins ( CSUC), Glen Haven ( CSUC), Manhattan ( CSUC), Mt. Margaret trail near Parvin Lake ( CSUC), Rd. to Pingree Pk. ( CSUC), Red Feather Lakes ( CSUC), Round Mt. trail Big Thompson Canyon ( CSUC); Las Animas Co.: Sugarite Canyon at Dorothy Lake ( CSUC); Montezuma Co.: Montezuma ( CSUC), W shore McPhee Res. ( CSUC); Montrose Co.: Government Springs ( DEBC); Morgan Co.: Ft. Morgan ( CSUC); Pueblo Co.: 2 mi. S San Isabel ( CSUC), Beulah ( CSUC); Weld Co.: Meadow Springs ( CSUC). Idaho: Latah Co.: Moscow Mountain ( DEBC). Montana: Hill Co.: Rocky Boy Indian Reserve ( CNCI). Oregon: Curry Co.: Little redwood campground ( CSUC); Lane Co.: Devil’s Elbow ( DEBC); Wallowa Co.: Whitman NF ( CNCI). South Dakota: Custer Co.: Custer ( CNCI). Utah: Beaver Co. ( DEBC); Daggett Co.: Elk Park, Ashley NF ( DEBC); Ouray Co.: Long Hollow, Dixie NF ( DEBC); Wasatch Co.: Wolf Creek Pass. ( DEBC).

Hosts. Picea engelmannii , Pinus attenuata , P. banksiana , P. contorta , P. flexilis , P. jeffreyi , P. ponderosa , P. radiata .

Distribution ( Fig. 23 ). NORTH AMERICA: USA. Alaska to New Mexico west of South Dakota.

Discussion. LeConte (1868) described Hylastes porosus from two specimens collected in California. He placed the species under Erichson’s first division of Hylastes based on tarsal and the mesoventrite characters as those of the second division ( Hylurgops sensu LeConte 1876 ). LeConte (1876) placed H. porosus in the genus Hylastes even after he erected the genus Hylurgops .

After examining a specimen originally designated by LeConte from Colorado, Swaine (1917) moved H. porosus to the genus Hylurgops describing it as a different species, Hylurgops lecontei . He made his determination based on differences in the degree of impression of the elytral striae (a character not currently used) as well as by differences in the size of pronotal punctures of the specimens he studied. Examined material throughout the range indicates that H. porosus can vary in size, degrees of elytral striae impression, and coloration, among other characters. However, these characters vary in series from the same area.

Swaine (1918) placed Hylastes porosus in the genus Hylurgops under the species with broad and bilobed third tarsal segments and anteriorly protuberant mesoventrite. Wood (1971c) synonymized H. lecontei with H. porosus after he examined the types of both species and considered them to be identical. Based on the characters followed in this review, H. porosus is considered to fit the generic concept of Hylurgops . To address the suggested hybridization between H. porosus and H. knausi made by Wood (1982) see H. knausi discussion section.

Figures

FIGURE 7. Aedeagus of the New World Hylurgops and Pachysquamus: a) Pachysquamus subcostulatus, b) Hylurgops planirostris, c) H. rugipennis, d) H. pinifex, e) H. incomptus, f) H. longipennis, g) H. knausi, h) H. reticulatus, and i) H. porosus.

FIGURE 12. Shape of elytral disc strial punctures in Hylurgops: a) round (H. longipennis), b) keyhole-shaped (H. pinifex), and c) keyhole-shape variation (H. planirostris).

FIGURE 17. Prothoraces of the New World Hylurgops: a) H. palliatus, b) H. planirostris, c) H. rugipennis, d) H. pinifex, e) H. incomptus, f) H. longipennis, g) H. knausi, h) H. reticulatus, and i) H. porosus.

FIGURE 22. Elytral disc surfaces of New World Hylurgops: a) surface reticulate (Hylurgops reticulatus), b) surface smooth and glossy (Hylurgops porosus).

FIGURE 23. Species distribution with two shared and widespread conifer hosts of Hylurgops reticulatus (squares) and H. porosus (circles).