Hylurgops knausi Swaine, 1917

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 : 330-331

Hylurgops knausi Swaine, 1917

( Figures 7 g, 14b, 15g, 17g, 18)

Hylurgops knausi Swaine, 1917:17 (Cloudcroft, New Mexico, USA) = Hylurgops planirostris Wood, 1971c:146

Diagnosis. This species is distinguished from the similar and sympatric H. reticulatus by the short, recumbent, hair-like ventral setae and by the overall smaller sized (thus more numerous) pronotal punctures ( Fig. 17 g–i). The presence of short pronotal setae distinguishes it from H. longipennis and H. incomptus in northern Mexico. The absence of a distinct anterior pronotal constriction, the straighter anterior margin of the elytra, the more elongated habitus, reduced elytral disc vestiture, more regularly sized small and large pronotal disc punctures, and the aedeagus with a moderate ventral lobe separate it from H. planirostris of southern Mexico to Honduras. Description. Size. Length 4.2–5.6 (avg. 4.7 ± 0.3) mm long, 2.7× longer than wide. Color. Mature adult dark brown to black, ventral sclerites dark brown to black with tarsi dark reddish. Frons. Transverse impression moderately strong; median carina extends from above epistomal margin to middle of convex area below frontal impression; vestiture short, recumbent, hair-like, 2× as long as the diameter of a one frontal puncture, 3× as long immediately above epistoma. Pronotum. As long as wide 1.0–1.1 (1.0 ±0.0) narrower than elytral margin at base, evenly or slowly widening to or slightly anterior to middle, where appears wider than elytral margin, then smoothly tapering anteriorly ( Fig. 14 b); basal ¼–⅓ of lateral margin narrowly constricted, slightly rounded at middle; middle line low, sometimes indicated only by a lack of punctures; discal punctures small, numerous, appearing regularly sized at low magnification, small ⅔ the size of large at magnifications> 100×, discal interpuncture surface shiny, with scattered reticulation; vestiture short, nearly indistinct, recumbent, hair-like setae the length of a puncture’s diameter on pronotal sides. Elytra. Interstriae glossy, 1.5× wider than striae on disc, surface rugose, with two to three rows of confused punctures, each with a short, recumbent, whitish hair-like seta, becoming semiplumose towards discal end; strial punctures small, keyhole-shaped ( Figs. 12 b–c), moderately impressed. Declivity. 3rd interstriae widest ( Fig. 15 g), slightly impressed, all with a single row of granules as tall as half as half size of a puncture; vestiture semi-erect, whitish hair-like setae as long as one (females) to four times (males) a discal puncture’s diameter, ground vestiture of four to five rows of short, recumbent, scale-like setae. Ventral sclerites. Finely reticulate; vestiture short, recumbent hair-like setae. Legs. Third tarsal segment slightly broader than second, bilobed. Aedeagus. Presenting a moderate ventral lobe ( Fig. 7 g).

Male. Declivital hair-like setae longer than in female.

Gallery: On stem collar and roots ( Livingstone 1980).

Material examined. 235 specimens. MEXICO. Chihuahua: Arroyo Mesteno, Sierra del Nido ( DEBC). Durango: 3 mi. E El Salto ( CNCI), 7 mi. W El Salto ( CNCI), 9 mi E El Palmito ( CNCI), 10 mi. SW El Salto ( CNCI), 10 mi. W El Salto ( CNCI, DEBC), 11 mi. SW El Salto ( CNCI), Buenos Aires 10 mi. W La Ciudad ( CNCI), Buenos Aires 10 mi. W El Salto ( CNCI, DEBC), Buenos Aires 37 mi. W La Ciudad ( CNCI), 24 mi. E El Salto ( CNCI), 24 mi. W La Ciudad ( CNCI), Ciudad ( CNCI). Nuevo Leon: Cerro Potosi ( CNCI, DEBC), NE slope Cerro Potosi, Mpio. Galeana ( CNCI). USA. Arizona: (no county) S. Arizona ( CNCI); Apache Co.: Alpine ( CNCI), Big Bonito Creek, White Mts. ( UAIC); Cochise Co.: Carr Canyon ( CNCI), Onion Saddle, Chiricagua Mountains ( CNCI), Paradise ( CNCI), Rustler “Park” Camp., Chiricagua Mountains ( CNCI); Graham Co.: Pinaleño Mountains ( CNCI, UAIC), Pinaleño Mountains, Soldier Creek ( UAIC); Gila Co.: Globe ( CNCI); Greenlee Co.: Buffalo Crossing, East Fork Black R., White Mts. ( UAIC), Hannagan Camp. ( CNCI); Pima Co.: Bear Wallow, Santa Catalina Mountains ( CNCI, DEBC), Carr Canyon, Huachuca Mountains ( CNCI), Florida Cny. Sta. Rita Range Res. ( UAIC), Green Spg., Mt. Lemmon ( UAIC), Mt. Bigalow ( UAIC), Santa Rita Mountains ( CNCI), Sierra Vista, Huachuca Mountains ( CNCI), Sta. Catalina Mts. ( DEBC), Sta. Catalina Mts. near Summerhaven ( UAIC); Santa Catalina Mountains ( CNCI), Santa Cruz Co.: Carr Canyon, Huachuca Mountains ( CNCI), Santa Rita Mountains ( CNCI). New Mexico: Grant Co.: McMillan Camp. 13 mi. N Silver City ( CNCI), McMillan Camp., 14 mi. N Silver City ( CNCI); Otero Co.: Cloudcroft ( CNCI, DEBC), Cloudcroft, Lectoparatypes 9243 ( CNCI), Lincoln NF 1 mi. SE Cloudcroft ( CNCI), Pine Camp., 2 mi. NE Cloudcroft ( CNCI); San Miguel Co.: near hot springs, Las Vegas ( CNCI); Socorro Co.: Bear Trap Camp., 28 mi. SW Magdalena ( CNCI).

Hosts. Picea engelmannii , Pinus arizonica , P. arizonica var. cooperi , P. duranguensis , P. hartwegii (new host, Cerro Potosi, Nuevo Leon, MX, Seybold 1993), P. leiophylla , P. ponderosa , P. pseudostrobus , P. strobiformis .

Distribution ( Fig. 18 ). NORTH AMERICA: MEXICO and USA. Arizona and New Mexico to Durango and Nuevo Leon, Mexico.

Discussion. Swaine (1917) described H. knausi from specimens collected in Cloudcroft, Otero County in New Mexico, and in 1918 placed the species under Hylurgops based on tarsal characters. Wood (1971c) compared Chapuis’ syntypes of H. planirostris with his homotypes of H. knausi and found them to be identical, and so treated them as synonymous. In his monograph’s key to Hylurgops, Wood (1982) placed the synonymized species under those lacking a distinct anterior constriction of the pronotum. Wood (1982) suggested that a slight intergrade of “characters” of this species with H. porosus occurred north of central Arizona and central New Mexico where the northern distribution limit of H. knausi and the southern of H. porosus (as suggested by Wood) meet. Although, no specimens of H. porosus from central AZ and none from any part of NM were examined, and Wood does not mention which were these characters, we can only speculate that confusion may have arisen when he examined males of H. knausi with long declivital setae or that he might have confused specimens of the sympatric H. reticulatus . Nevertheless, the two specimens upon which he based his comments may represent aberrant specimens. The full species designation given by Swaine (1917) is considered valid by the characters discussed in the specific key, diagnosis, and description.

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 14. Hylurgops, prothorax proportion and shape: a) wider than long and constricted anteriorly (H. planirostris), b) longer than wide and smoothly tapering anteriorly (H. knausi).

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 18. Species distribution of Hylurgops knausi (squares), including the main hosts: Pinus ponderosae, P. arizonica, and P. durangeuensis (dark grey); and the distribution of H. planirostris (circles), with its main hosts: P. hartwegii and P. montezumae (light gray). Insert shows detail of H. planirostris ’ distribution. Host polygons adapted from Little (1991).