Bryelmis siskiyou Barr, 2011

Barr, Cheryl B., 2011, BryelmisBarr (Coleoptera: Elmidae: Elminae), a New Genus of Riffle Beetle with Three New Species from the Pacific Northwest, U. S. A., The Coleopterists Bulletin 65 (3), pp. 197-212 : 197-212

Bryelmis siskiyou Barr , new species ( Figs. 6 , 9 , 10 , 12 )

Description. Length 1.8–2.3 mm, width 0.92– 1.14 mm. Body color dark brown to black; appearing smooth, with elytral carinae, striae, and punctures not prominent. Antenna: Testaceous, often darker at tip. Head: Black. Eyes weakly protuberant. Frons with scattered small punctures bearing fine setae. Clypeus with fine, evenly spaced punctures more than 2X their diameters apart, integument between punctures smooth. Labrum faintly emarginate, smooth, with fine, evenly spaced punctures bearing setae; apico-lateral, and occasionally mediolateral, margins with dense clusters of setae. Pronotum: Dark brown to black, shiny. Slightly wider than long, widest about 1/3 distance from base; length 0.58–0.70 mm, width at widest point 0.7–0.9 mm. Basolateral angles nearly forming right angles, lateral margin often slightly sinuate near base. Disc shiny, with small, widely spaced punctures accompanied by fine setae; narrow, often indistinct median longitudinal carina extending from near apical margin to near base where it becomes faint or absent. Sublateral carinae usually narrow but not sharply carinate; each bordered medially by a shallow, broad basal and an indistinct apical fossa. Elytron: Convex; shiny with short, sparse setae, medium brown to black. Length 1.3– 1.6 mm, width 0.44–0.56 mm. Disk lateral to suture usually slightly depressed at basal 1/3. A low, sublateral carina present at interval 7, most developed at apical 1/3, abruptly ending at about 1/5 of the distance from the elytral apex; a slightly shorter carina present at interval 8; both carinae often indistinct. Shallow longitudinal sulcus with deeper fovea containing enlarged punctures adjacent to metasternum. Nine striae with shallow to moderately deep punctures separated by 1X their diameters. Leg: Shiny red-brown, except for distal 1/4–1/3 of femur which is dark brown, or entirely dark brown; visible portion of femur dark in dorsal habitus view. Femur with closely spaced, minute punctures and sparse setae. Venter: Shiny, red-brown to dark brown medially, prosternum darkest; dense silver to golden plastron present laterally. Apex of prosternum narrowly to broadly rounded. Mesosternal disc shallowly concave between mesocoxae. Metasternal disc slightly convex. Male genitalia: In dorsal view ( Fig. 6 ), parameres with outer margins constricted medially, tips narrowly rounded. Penis slightly longer than parameres, slender, and nearly parallel-sided in basal two-thirds, then gradually narrowed to a tip which is not as wide as that of a paramere.

Variation. In B. siskiyou , the development of the longitudinal median pronotal carina and the sublateral elytral carinae varies from fairly visible to low and indistinct. An elytral depression at the basal 1/3, normally present in Bryelmis , may not be evident in some individuals. Metathoracic wings may be present or absent. Females (n = 3) were slightly longer than males (n = 3) in a comparison of the length measurements of the longest and shortest specimens, with the longest specimen a female and the shortest a male.

Comparative and Diagnostic Comments. Externally, B. siskiyou ( Fig. 9 ) most closely resembles B. rivularis , but differs in that the median pronotal carina is reduced, the sublateral elytral carinae are usually not as prominent, and the elytra are not deeply striate and punctate, giving the body a smooth appearance. Conversely, in B. rivularis ( Fig. 8 ) the median pronotal carina is distinct, the sublateral elytral carinae are prominent, and the elytra are deeply striate with large punctures. In addition, the male genitalia of B. siskiyou ( Fig. 6 ) have parameres which are straight at the tips, whereas B. rivularis ( Fig. 7 ) has the paramere tips angled outward. Bryelmis idahoensis ( Figs. 3, 4 ) is more rugose and sculptured with prominent carinae, sulci, striae, and punctures; unlike B. siskiyou and B. rivularis , the median pronotal carina is produced and ridgelike, the pronotal disc is smooth with few punctures and setae, and the lateral elytral sulcus is deep and trench-like.

Material Examined. 59 specimens. HOLO- TYPE ♂ in EMEC, labeled: “CA: Shasta Co., Shasta NF, trib. Castle Cr., spring run at FS Rd. 25 5.4 rd. mi. W jct. I-5, 17-IX-1994, C. B. Barr // HOLOTYPE Bryelmis siskiyou Barr ” [red label]. Forty-two paratypes (P) [yellow labels] and 16 non-paratypes ( NP) were examined from the following localities: Same data as holotype (2 P, BNHM; 1 P, CASC; 7 P, 1 NP, EMEC; 1 P, OSAC; 2 P, USNM); CALIFORNIA: Del Norte Co.: Six Rivers NF, trib. N. Fk. Smith R. at Cooper Flat , Hwy. 199 4 mi. W Gasquet, 10-VI-2008, coll. C. B. Barr (2 P, EMEC) . Humboldt Co.: Six Rivers Natl. Forest, Dragsaw Spring at FS Rd. 13N01, VII-29-2007, coll. J. J. Lee (2 NP, JJLC) ; Six Rivers Natl. Forest, Dragsaw Spring at F.S. Rd. 13N01, 14-VI-2008, C. B. Barr // 41.24789° N, 123.69340° W, elevation 784m (7 P, EMEC) ; data same, except W. D. Shepard (1 NP, WDSC) ; Six Rivers Natl. Forest, Red Mountain Creek at FS Rd. 10N12, V-30-02, coll. J. J. Lee (1 NP, JJLC) ; data same, except VI-6-03 (2 NP, JJLC); data same, except VIII-27-06 (1 NP, JJLC); data same, except 23-VIII-2007 (1 NP, JJLC) ; Six Rivers Natl. Forest, Red Mountain Creek at F.S. Rd. 10N12, 14 - VI- 2008, C. B. Barr // 41.24697 ° N, 123.68943° W, elevation 722m (2 P, EMEC) ; data same, except W. D. Shepard (2 NP, WDSC) ; Redwood Creek trib. 10.6 km E Maple Creek, 7- VIII-2001 // 40°45′17″N, 123°44′23″W, elev. ∼ 1050 m // California Dept. of Fish & Game, ML #7063 E-Map (1 P, EMEC) . Shasta Co.: Shasta NF, Castle Creek at FS Rd. 25, 7.7 rd. mi. W jct. I-5, 17-IX-1994, C. B. Barr // collected from seep at creek margin (1 P, EMEC) ; Shasta NF, trib. Damnation Creek at Dog Cr. Rd. // FS 8G012 1 rd. mi. E Clear Cr. Cgd. , 30-V-1994, coll. C.B. Barr (3 P, 2 NP, EMEC) ; Shasta NF, tributary Dog Creek at Dog Cr. Rd. // FS 8G012 6 rd. mi. W of I-5/ Vollmers , 30-V-1994, coll. C. B. Barr (1 P, 1 NP, EMEC) . Siskiyou Co.: Buckhorn Creek ∼ 16 mi. SE Happy Camp, 2-X-2001 // 41°39′48″N, 123°16′36″W, elev. ∼ 430 m // California Dept. of Fish & Game, ML #7304 E-Map (1 P, EMEC) ; Head of W. Branch Indian creek at Poker Flat 5040′, 14.VIII.1966 // collector Hugh B. Leech (1 P, CASC) ; 3 mi SE Cecilville, 21-VII-1990, S Fk Salmon River // William D. Shepard, leg. (2 P, WDSC) . Trinity Co.: 12 mi N Trinity Ctr, 20- VII-1990, Eagle Creek // William D. Shepard, leg. (1 P, WDSC) ; 10 mi N Weaverville , 18-VII-1990, Stuart Fork // William D. Shepard, leg. (1 P, WDSC) ; 5.8 mi SW Trinity Center , 18-VII-1990, E Fk Stuart Fork // William D. Shepard, leg. (1 P, WDSC) . OREGON: Douglas Co.: mouth W. Fk. Bobby Cr. 16 mi. WNW Glendale, elev. 1924 ft., 12-X-1993, R.W. Wisseman // 42°48′03.99″N, 123°43′38.13″W, BLM Medford Dist. monitoring site (1 P, EMEC) . Jackson Co.: Lake Creek at mouth, 14 mi. NE of Medford nr. Hwy. 140, X-1994, R.W. Wisseman collr. // 42°25′16.58″N, 122°37′14.63″W, elev.1620′, BLM Medford District monitoring site (1 P, EMEC) . Josephine Co.: Siskiyou NF, Phillips Cr. 24 mi. W Grants Pass, elev. 3479 ft., 24-IX-1992, A. Haspiel // off FS Rd. 2512-663, 42°26′13.93″N, 123°48′15.46″W (4 P, EMEC; 1 NP, ABAC) .

Distribution, Habitat, and Biology. Bryelmis siskiyou occurs in the coastal mountain ranges of northwestern California and in extreme southwestern Oregon. It has been collected as far east as the western Cascades ( Fig. 10 ).

The type locality, an unnamed tributary of Castle Creek west of Castle Crags State Park, CA, is a small, less than 0.5 m wide, incised spring run with clear, cold water in a heavily forested area. I collected a series of 15 adult specimens from C. polyanthos rivularis , which was growing in abundance a short distance downstream from the spring source. The additional six localities where I have collected the species were likewise forested, with habitats ranging from tiny spring runs ( Fig. 12 ) to small streams, all with clear, cold water. At none of these sites, except for the type locality, was the species abundant. Adults and larvae of B. siskiyou were found inhabiting aquatic bryophytes in these waters as well, and at Red Mountain Creek (Humboldt Co., CA), C. polyanthos rivularis was verified as the microhabitat. I have recorded the following elmid species co-occurring with B. siskiyou at one or more of the collecting localities: Ampumixis dispar (Fall) , A. wawona , C. addenda , H. koebeli , L. avara , N. concolor , O. quadrimaculatus , Ordobrevia nubifera (Fall) , Rhizelmis nigra Chandler , and Z. parvula .

Etymology. The specific epithet, siskiyou , refers to the mountain range, national forest, and county of the same name, all within the geographic range of the species. The origin of the word is unknown, but has been speculated to have been derived in the mid-1800s from Chinook or French names.

Figures

Figs. 5–7. Male genitalia of Bryelmis spp. 5) B. idahoensis, dorsal view; 6) B. siskiyou, dorsal view; 7) B. rivularis, a) Dorsal view, b) Lateral view.

Figs. 8–9. Habitus of Bryelmis spp. 8) B. rivularis, a) Dorsal, b) Lateral; 9) B. siskiyou, a) Dorsal, b) Lateral. Scale bars = 0.5 mm.

Fig. 10. Known distribution of Bryelmis spp. in North America: B. idahoensis (circles), B. rivularis (squares), and B. siskiyou (triangles).

Figs. 11–13. 11) Fern Creek, Clearwater Co., ID, type locality of Bryelmis idahoensis; 12) Dragsaw Spring, Humboldt Co., CA, habitat of Bryelmis siskiyou; 13) Hell Roaring Creek, Jefferson Co., WA, type locality of Bryelmis rivularis.

Figs. 3–4. Habitus of Bryelmis idahoensis. a) Dorsal, b) Lateral. Scale bars = 0.5 mm.