Phlaeopterus frosti Hatch, 1957

Mullen, Logan J., Campbell, J. M. & Sikes, Derek S., 2018, Taxonomic Revision of the Rove Beetle Genus Phlaeopterus Motschulsky, 1853 (Coleoptera: Staphylinidae: Omaliinae: Anthophagini), The Coleopterists Bulletin 72, pp. 1-54 : 31-32

7. Phlaeopterus frosti Hatch, 1957

( Figs. 2C , 9A, 17B , 18A , 20D , 25A , 36D )

Phlaeopterus frosti Hatch 1957: 59 [original description]. Campbell and Davies 1991: 5; Bousquet et al. 2013: 89.

Type Locality. Mt. Rainier , Washington, USA .

Redescription. Habitus: Length 5.8–7.2 mm. Reddish brown to black; legs, elytral epipleura, tarsi, and apices of tibiae lighter reddish brown to yellowish brown ( Fig. 2C ). Head: Slightly broader than long, ratio of width across eyes to head length = 4:3. Interantennal groove broadly and deeply impressed. Anteocellar foveae large, deeply impressed. Eyes glabrous or with less than 10 scattered hairs near ventral margin ( Fig. 36D ). Antennomeres 5–10 at least 2 times longer than wide; antennomeres 4–11 each with many sensory pits with papilliform projections. Ocelli present. Nuchal constriction vague. Mandibular molar area with L-shaped row of setae. Labrum with sensory pores along entire surface. Labial palpi with 3 rd palpomere 1.6–1.8 times longer than palpomere 2. Thorax: Pronotum moderately wide ( Fig. 17B ), length to width ratio = 0.68–0.72; ratio of pronotal width to head width = 1.54–1.67; maximum width subequal to elytral width at humeral angles; punctures separated by distance equal to slightly greater than diameter of a puncture; lateral margins explanate posterad but not anterad lateral foveae; lateral foveae deeply impressed. Elytra with humeral angles convex; epipleural carina not projecting; 2.1–2.2 times longer than pronotum; apical margins convex or subtruncate. Wings fully developed in most indivuals, brachypterous in very few. Mesosternum with projecting tooth; longitudinal carina along midline of mesosternum distinct on anterior half, distinct or reduced on posterior half ( Fig. 20D ). Legs: Apices of all tibiae glabrous, subglabrous apex of mesotibia subequal to length of basal 4 mesotarsomeres ( Fig. 18A ), length of subglabrous apical region of metatibia as ratio to metatibial length in males = 4.9–8.4, in females = 4.2–5.5. Metatrochanter without tooth on apical margin. Abdomen: Wing-folding spicules on tergites IV and V; shape of wing-folding patches on tergite V broadly oval and narrowly separate. Aedeagus: Length 1.23–1.40 mm. Median lobe somewhat triangular with sides narrowing from base to apex; apex not carinate ( Fig. 25A ). Parameres extending slightly beyond apex of median lobe. Internal sac rectangular and elongate; heavily sclerotized, uniformly covered with microspinules; lacking subapical transverse fold.

Type Specimens. Holotype male (UAMObs: Ento:235778) and allotype female (UAMObs:Ento: 235779) labeled as follows: Mt. Rainier , WASH., below Sluskin Falls, Aug. 23, 1930 M.H. Hatch TYPE ³ (or ALLOTYPE ♀), Phlaeopterus frosti, 1951 – M.H. Hatch. Both specimens are in the USNM.

Distribution. Phlaeopterus frosti is found in the Cascade Range from Oregon north to Manning Provincial Park, British Columbia, the Olympic Mountains of Washington, the Pacific Coast Range, Selkirk Mountains, and southern Rocky Mountains of British Columbia, and the Kenai Mountains of Alaska ( Fig. 9A).

Bionomics. Adults have been collected at 50–2,050 m elevation during June–August. This species has been collected on the surface of permanent or long-lasting snowfields at night in Washington and Oregon, where they forage immediately after dusk, and during the day in British Columbia. They have also been collected under rocks at the edges of snowfields and cold, fast-flowing streams, in moss growing in the splash-zones of waterfalls, and occasionally in the gravelly, marshy edges of high elevation lakes. On the surface of snowfields, they have been observed feeding on small insects (mostly Diptera) stranded on the surface of the snow.

Remarks. Phlaeopterus frosti can be distinguished from all other Phlaeopterus species by the shape of the pronotum (length:width ratio, lateral margins, and lateral foveae), the glabrous region at the apex of the tibiae, and the form of the aedeagus. This species is very similar to P. fusconiger but can be distinguished by the characters discussed in the Remarks section of the latter species. These two species are sympatric in the Pacific Coast Range from the Olympic Mountains of Washington north to the Kenai Mountains of Alaska.

Figures

Fig. 2. Phlaeopterus species, habitus. A) P. elongatus, male (UAMObs:Ento:232543), B) P. filicornis, female

Fig. 17. Phlaeopterus species. Pronota, dorsal view, of A) P. fusconiger, B) P. frosti, C) P. filicornis, D) P. hatchi, E) P. elongatus. Abdominal segments 4–6, dorsal view, of F) P. houkae, G) P. obsoletus, H) P. elongatus.

Fig. 18. Mesotibiae, dorsal view, of A) Phlaeopterus frosti (UAMObs:Ento:235497), and B) Phlaeopterus fusconiger (UAMObs:Ento:235751). Red highlights are added to emphasize the difference in the length of the subglabrous region (lacking dense pubescence but with longer spine-like setae) at the apex of the tibia.

Fig. 20. Phlaeopterus species, mesosterna, ventral oblique view. A) P. longipennis, B) P. obsoletus, C) P. olympicus, D) P. frosti, E) P. occidentalis, F) P. elongatus.

Fig. 25. Phlaeopterus species, aedeagi (left = ventral view; right = dorsal view of median lobe). A) Phlaeopterus frosti, B) P. hatchi, C) P. filicornis, D) P. elongatus.

Fig. 36. Phlaeopterus species, eyes, dorsal view. A) P. lagrandeuri, B) P. houkae, C) P. longipennis, D) P. frosti, E) P. bakerensis, F) P. olympicus.