Macrohydnobius matthewsii Peck & Cook 2009, new combination
Creators: name: Peck, Stewart B.
name: Cook, Joyce
Publisher: name: Zenodo
Year: 2009
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Leiodidae
Macrohydnobius
Macrohydnobius matthewsii

description: Macrohydnobius matthewsii (Crotch, 1874), new combination   
(Figs. 101–106, 107)  
 Hydnobius matthewsii Crotch, 1874: 74; Horn 1880: 280; Hatch 1957: 24.   
 Hydnobius stacesmithi Hatch 1957: 34, new synonymy.   
 Type material. Lectotype of H. matthewsii here designated to ensure the name’s proper and consistent application, male, in MCZC, bearing white label “Van.”; red and white label “Type / 3200”; white handwritten label “ Hydnobius / matthewsii / Crotch”; and our red lectotype label; seen and dissected. Type locality: Gold Stream, Vancouver Island.   
 Hydnobius stacesmithi, holotype, male, in SMDV, bearing white label “Copper Mtn. / B.C. 30.X.1929 / G. Stace Smith ”; white handwritten label “on snow”; red handwritten label “TYPE [male symbol] / Hydnobius / stace-smithi / 1954 – M. Hatch ”; and white label “ Ex. G. Stace-Smith / collection / purchased 1960”; seen and dissected. Type locality: Copper Mtn., British Columbia.   
 Additional material examined. We examined 261 specimens (See Appendix).   
 Diagnosis. Body yellowish to reddish brown, moderately shining. Length of pronotum + elytra = 3.9–5.7 mm (males), 3.8–6.0 mm (females). Head finely punctate, with a median longitudinal depression between eyes and extending onto clypeus. Pronotum narrow, widest at basal one-third, sides rounded, basal angles obtuse; with a pair of small basal impressions joined by an irregular row of punctures, marked by a transverse line of dark pigmentation; ratio length:width = 1:1.4; finely punctate, with no microsculpture. Elytra wider than pronotum, elongate, ratio length:width = 1:0.7; with 9 closely punctate, weakly impressed striae; striae 6 and 7 do not reach apex; intervals with 2–3 rows of fine punctures, uneven intervals with scattered larger punctures and transversely striolate. Antennal club (Fig. 101) moderately slender, ratio club width:length = 1:3.1; width ratio of antennomeres 7:8:9 = 1.3:1:1.6. Mandibles (Fig. 102) elongate, broad at base, narrow apically; lacking teeth on outer margins; left mandible with acute tooth on apical one-half of inner margin; right mandible irregularly dentate at middle of inner margin. Metatrochanter lacking a tooth before apex. All femora unarmed in both sexes. Male protibia (Fig. 103) broad at apex, spinose on outer margin, with large sinuate spur at apex; female protibia similar in shape but apical spur unmodified; mesotibia and metatibia of both sexes narrow, slightly widened apically, spinose. Male. Aedeagus (Fig. 104) with median lobe elongate, narrower in apical two-fifths, triangular at apex. Parameres narrow and short, inserted at apical two-fifths of median lobe and not reaching apex; short setae apically. Internal sac with scale-like setae with tapered apices, visible as a pair of elongate rows when inverted. Female. Coxites (Fig. 106) elongate, cylindrical, with subapical setae; styli moderately elongate, inserted at apices of coxites. Sternite 8 (Fig. 105) truncate apically, anterior apophysis broadly triangular.   
 Nomenclatural notes. Agathidium pallidum was described by Thomas Say (1824: 91). The specimen was subsequently lost or destroyed (Ord 1859, Mawdsley 1993). The name has been associated with Hydnobius matthewsii Crotch. Horn (1880: 281) states that it “may be this species” under his account of H. matthewsii. The name was associated with H. matthewsii by Hatch (1929: 11) as “? pallidum Say ”. Based on Say’s sufficiently clear description we can determine that the specimen was not Macrohydnobius matthewsii (Crotch) and we are unable to place it within the Sogdini and assume it is in the Agathidiini. The type locality was stated as “Engineer Cantonment” which was the winter encampment of the 1819–20 expedition, led by Major Stephen H. Long, to explore the southern Rocky Mountains (Beidleman 1986). Archaeological investigation by the Nebraska State Historical Society has established the site of the encampment on the bank of the Missouri River, a few miles north of present-day Omaha (Carlson et al. 2004).   
 Distribution. The species occurs in forested northwestern North America and to the east to Wyoming (Fig. 107). We have seen specimens from Canada: the province of British Columbia; USA: the states of California, Idaho, Montana, Oregon, Washington, and Wyoming.   
 Field notes and habitats. Adults have been collected most frequently on snow, with a few in flight intercept and pitfall traps, with eight in pitfall traps in sand dunes, five on hypogeous Gautieria fungi and five on Rhizopogon fungi.   
 Seasonality. Adults have been collected from August to January, with the exception of one in June. The greatest numbers are for October (32), November (113), and December (21).
description: Published as part of Peck, Stewart B. & Cook, Joyce, 2009, Review of the Sogdini of North and Central America (Coleoptera: Leiodidae: Leiodinae) with descriptions of fourteen new species and three new genera, pp. 1-74 in Zootaxa 2102 (1) on pages 38-40, DOI: 10.11646/zootaxa.2102.1.1, http://zenodo.org/record/5310884