Hylurgops reticulatus Wood, 1971

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 : 331-333

Hylurgops reticulatus Wood, 1971

( Figures 6 b, 7h, 15h, 17h, 22a, 23)

Hylurgops reticulatus Wood, 1971b:71 (Summit Lake, Shasta County, California, USA)

Diagnosis. Hylurgops reticulatus is distinguished from the sympatric H. porosus at high (> 50×) magnification by the completely reticulate elytral surfaces ( Fig. 22 a), also by the ventral lobe of the aedeagus ( Fig. 7 h). It is distinguished from H. knausi by a greater size difference between the large and small pronotal punctures, by the long, hair-like setae on the ventral surfaces and from dark brown specimens of H. pinifex occurring in Colorado by the longer than wide pronotum ( Fig. 17 h), which tapers smoothly anteriorly.

Description. Size. Length 3.9–5.3 (avg. 4.5 ± 0.4) mm long, 2.8× longer than wide. Color. Mature adult black to dark brownish-red, if bicolored (rarely) it presents a black pronotum and a reddish-brown to brown elytra, ventral sclerites dark brownish-red to black with dark femur and tibiae and lighter tarsi. Frons. Middle impression moderately deep; carina elevated, extends from middle impression to epistoma, surface smooth to reticulate; vestiture hair-like setae, longer below middle, 2–7× the size of a puncture diameter. Pronotum. Elongate 1.0–1.1 (1.1 ± 0), base narrower than elytral anterior margin; smoothly tapering anteriorly ( Fig. 17 h), widest near middle; median line present lengthwise, slightly raised, its surface reticulate; discal punctures of two sizes, the smaller more abundant (2:1), the larger 3× diameter of the smaller, inner surface shiny or dull, inter-puncture area reticulate, some with scattered smooth areas; discal setae sparse to absent, short, recumbent, whitish, hair-like, averaging length of small punctures at disc, 2× longer at marginal areas; basal ⅔ of lateral margin narrowly rounded, becoming broadly rounded anteriorly to a slight apical constriction. Elytra. Anterior margin almost straight; striae straight, shallowly concave, punctures round, shiny, separated by half their diameter on disc; interstriae slightly wider than striae, evenly reticulate (visible at> 50×, Fig. 22 a), punctures minute, confused, a middle row of erect, whitish hair-like setae arising from behind each granule, setae as long as a discal strial puncture width, becoming longer posteriorly, separated by 1.5× strial puncture width. Declivity. Striae slightly impressed, as wide as most interstriae except the third ( Fig. 15 h), punctures round and deep, smaller than at disc, separated by half their diameter’s length, second interstriae slightly impressed, all with pointed granules separated by 1.5× a puncture diameter, with ground vestiture of small, round, scale-like setae, 3–4 rows across interstriae, uniseriate midline of erect, whitish hair-like setae as long or slightly longer than interstrial width. Ventral sclerites. Surface punctured, reticulate; vestiture distinctly long, hair-like; precoxal ridge acutely elevated. 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. Of typical Hylurgops type, with a distinct ventral lobe in the aedeagus ( Fig. 7 h).

Gallery: As in H. porosus ( Wood 1982) : uniramous, longitudinal, with broods mining perpendicular to the brood gallery.

Material examined. 110 specimens. CANADA. Alberta: Lake Louise ( CNCI). British Columbia: Creston ( CNCI), Enderby ( CNCI), Indian Meadows, Manning Provincial Park ( CNCI), Midday Creek ( CNCI), Midday Valley, Merritt ( CNCI), Midday Valley, Merritt Paratypes No. 12578 ( CNCI), Lake Cowichan ( CNCI), Oliver ( CNCI), Robson ( CNCI), Spious Creek ( CNCI), Summerland ( CNCI), Trinity Valley ( CNCI), Vancouver, Mesachie Lake ( CNCI), Voght Valley ( CNCI). MEXICO. Durango: 10 mi. SW El Salto ( CNCI). USA. Arizona: Coconino Co.: Flagstaff ( DEBC). California: Lassen Co.: Black Mountain ( DEBC); Lassen NF ( CNCI); Los Angeles Co.: Big Pines ( CNCI, DEBC); Mendocino Co.: Mendocino ( DEBC); Plumas Co.: Jackson Ck. ( DEBC), Meadow Valley ( CNCI); San Bernandino Co.: Baldwin Lake ( CNCI), Big Bear Lake ( CNCI); Shasta Co.: Old Station ( DEBC). Colorado: El Paso Co.: 15 mi. S. Colorado Springs ( CNCI); Montezuma Co. ( CSUC). New Mexico: Otero Co.: Cloudcroft ( CNCI). Oregon: Josephine Co. ( DEBC); Klamath Co.: 7 mi. SW Fort Klamath ( CNCI); Utah: Juab Co.: Eureka ( CNCI), The Mammoth ( CNCI).

Hosts: Picea engelmannii , P. sitchensis , Pinus arizonica var. cooperi (new host, El Salto, Durango, MX, Coll. J.B. Thomas 1964), P. attenuata , P. contorta , P. jeffreyi , P. monticola , P. muricata , P. ponderosa , P. radiata , Pseudotsuga menziesii , Tsuga heterophylla .

Distribution ( Fig. 23 ). NORTH AMERICA: From southern Alaska to Durango, Mexico.

Discussion. Wood (1971b) described H. reticulatus from specimens he collected in 1946 at Summit in Shasta County, California. He mentioned that H. reticulatus was previously confused with H. porosus and Hylastes macer LeConte , the latter also having a reticulate elytral surface.

The third tarsal segments of H. reticulatus are not as broad as in other Hylurgops ; however, they are not narrow as in Hylastes . The pronotal punctures are of two distinct sizes that are intermixed ( Fig. 17 h). The species resembles H. porosus and occurs in sympatry with it throughout most of its distribution.

Figures

FIGURE 6. Aedeagus and spiculum gastrale: a) Pachysquamus subcostulatus, b) Hylurgops reticulatus, c) Hylastes ater (modified from Grocholski et al. 1976), d) Hylurgops rugipennis.

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 15. Elytral declivities of 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 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).