Phlaeopterus castaneus ( Casey, 1893 )

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 : 10-16

2. Phlaeopterus castaneus ( Casey, 1893)

( Figs. 1B , 6B , 16B, 21F, 22A)

Tilea castanea Casey 1893: 403 [original description].

Phlaeopterus castaneus ( Casey, 1893) . Moore and Legner 1975: 208; Campbell and Davies 1991: 5; Bousquet et al. 2013: 89.

(UAMObs:Ento bars = 1 mm.

:234040), C) P. cavicollis , male (UAMObs:Ento:235795), D) P. czerskyi , female. Scale (UAMObs:Ento:232406), C) P

235496). Scale bars = 1 mm.

UAMObs:Ento:. frosti , male (UAMObs:Ento:235798), D) P. fusconiger , female (Ento:234115),

Scale bars =:Ento:234056). C) P. kavanaughi , female (UAMObs:Ento:232423), D) P. lagrandeuri , female (UAMObs 1 mm.

(UAMObs:Ento:235802), C) P.

233445). Scale bars = 1 mm.

UAMObs:Ento: (UAMObs:Ento:233301). Scale bars = 1 mm.

Phlaeopterus cascadiensis Hatch 1957: 59 [original description]. Campbell and Davies 1991: 5. New status as subspecies and synonymy.

Type Locality. Colorado, USA .

Redescription. Habitus: Length 5.6–7.7 mm. Dark brown to reddish brown; lateral margins of pronotum often lighter ( Fig. 1B ); head, elytra, palpi, and antennae sometimes lighter. Head: Moderately broad, ratio of width across eyes to length of head = 1.0–1.3. Interantennal groove broadly and deeply impressed. Anteocellar foveae large, deeply impressed. Eyes glabrous or with less than 10 scattered setae near ventral margin. 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 broad (Fig. 16B), length to width ratio = 0.63–0.73; ratio of pronotal width to head width 1.5–1.61; maximum width subequal to elytral width at humeral angles; punctures on dorsal surface separated by average distance equal to twice diameter of a puncture; lateral margins explanate posterad lateral foveae, narrowly explanate ( P. castaneus castaneus ) to not explanate ( P. castaneus cascadiensis ) anterad lateral foveae; lateral foveae deeply impressed. Elytra with humeral angles convex; epipleural carina not projecting; 2.2–2.5 times longer than pronotum; apical margins broadly convex, uniformly dark reddish brown ( P. castaneus castaneus ) or with sutural area lighter reddish brown than remainder of elytral surface ( P. castaneus cascadiensis ). Wings fully developed in most individuals, brachypterous in very few. Mesosternum with projecting tooth; longitudinal carina along midline of mesosternum complete but not strongly carinate. Legs: All tibiae with dense pubescence from base to apex. Metatrochanter without tooth on apical margin. Abdomen: Wing-folding spicules on tergites IV and V broad, transverse, narrowly separated; tergite VI lacking wing-folding patches. Aedeagus: Length 1.20–1.36 mm for P. castaneus cascadiensis (Fig. 21F), 1.32–1.48 mm for P. castaneus castaneus ( Fig. 22A ). Median lobe narrowed abruptly just before apex, with longitudinal carina at apex. Parameres narrow. Internal sac variable; 2/3 to half length of median lobe; covered in microspinules; with or without subapical transverse fold.

Type Specimens. Tilea castanea : Lectotype male (here designated, UAMObs:Ento:235783) labeled as follows: Col./³/CASEY bequest 1925/ TYPE USNM 48100/[ Tilea ] Castanea [sic]/ LECTOTYPE ³ Phlaeopterus castanea (Casey) des. 1984, J.M. Campbell. Paralectotype male (here designated) labeled as follows: CASEY bequest 1925/castanea PARATYPE USNM 48110. We designated these specimens as lectotype and paralectotype to clarify the application of this name to this taxon and because a holotype was not designated in the series examined by Casey (1893), which comprised two specimens.

Phlaeopterus cascadiensis : Holotype male (UAMObs:Ento:235219) and allotype female (UAMObs:Ento:235777) labeled as follows: Mt. Rainier, WASH., Tipsoo Lake, Aug. 2, 1938, M.H. Hatch/TYPE ³ (or ALLOTYPE ♀) Phlaeopterus cascadiensis 1951 – M.H. Hatch.

All four specimens are in the USNM.

Distribution. Phlaeopterus castaneus castaneus is known from the Rocky Mountains of Alberta south to Colorado and west to eastern Oregon, eastern Washington, and Garibaldi Provincial Park, British Columbia ( Fig. 6B ). Phlaeopterus castaneus cascadiensis is known from the Aleutian Islands and southeastern Alaska, and the Pacific Coast and Cascade Ranges of British Columbia south to Oregon ( Fig. 6B ). We confirm the surprising occurrence of this species on Unalaska Island from a single specimen (UAMObs:Ento:233345).

Bionomics. This species has been collected at elevations of 500–2,500 m at the edges of cold, fast streams and sometimes at the edges of snowfields and lakes fed by melting snow.

Remarks. Phlaeopterus castaneus can be distinguished from all other Phlaeopterus species by the shape of the pronotum, tibiae evenly pubescent to apex, mesosternum weakly but completely carinate, and the form of the aedeagus. We chose to classify P. cascadiensis as a subspecies of P. castaneus primarily because of the abundance of intermediate forms at the zone of overlap of the two taxa. The two subspecies can be distinguished throughout most of their range by the length and microspinules of the internal sac of the aedeagus, the explanate lateral margins of the pronotum, and, to some extent, the coloration of the elytra. However, in Garibaldi and Manning Provincial Parks, intermediate states of microspinules of the internal sac and the explanate lateral margins of the pronotum can be found. The two subspecies are diagnosable throughout their range except in the zone of overlap in Garibaldi and Manning Provincial Parks, British Columbia.

Figures

Fig. 1. Phlaeopterus species, habitus. A) P. bakerensis, female (UAMObs:Ento:233271), B) P. castaneus, female

Fig. 6. Distributions of Phlaeopterus species based on all georeferenced specimen records. A) P. bakerensis, B) P. castaneus. Grey dots represent localities where at least one Phlaeopterus species, but not the species of interest, was collected. Red dots represent localities where the species of interest was collected. In B, red triangles represent localities of P. castaneus castaneus, red squares represent localities of P. castaneus cascadiensis, and green stars represent areas of overlap of the two subspecies.

Fig. 22. Phlaeopterus species, aedeagi (left = ventral view; right = dorsal view of median lobe). A) P. castaneus castaneus, B–D) variation in P. cavicollis.