Bembidion breve, (MOTSCHULSKY)

Sproul, John S. & Maddison, David R., 2018, Cryptic species in the mountaintops: species delimitation and taxonomy of the Bembidion breve species group (Coleoptera: Carabidae) aided by genomic architecture of a century-old type specimen, Zoological Journal of the Linnean Society 183, pp. 556-583 : 576

BEMBIDION BREVE (MOTSCHULSKY)

( FIGS 1C, 8E, F, 10C, 11C, 13A, 14B)

Peryphus brevis Motschulsky, 1845: 28 . Lectotype male, designated by Bousquet & Larochelle (1993: 16), in ZMMU, labelled ‘ Plataphus brevis Motsch [illegible]’ [green paper, handwritten], ‘ B. breve Mtsch spec. interto proxima cfr. et. tetraglyptum dt. Netolitzky’ [white paper, handwritten; ‘interto’ is likely a mispelling of ‘incerto’], [red rectangle], ‘ LECTOTYPE Peryphus brevis Motschulsky Des. by Y. Bousquet’ [red paper, partly handwritten]. Type locality: Sitka, Alaska. Examined, including genitalia.

Notaphus incertus Motschulsky, 1845: 350 . Lectotype male, designated herein, in ZMMU, labelled ‘Sitka’ [green paper, handwritten], ‘ Plataphus incertus Motsc Am. b. [illegible] Sitka’ [green paper, handwritten], ‘ B. incertum Mts spec. [illegible] det Netolitsky’ [white paper, handwritten], ‘ LECTOTYPE Notaphus incertus Mtsch. designated Sproul & Maddison 2014 ’ [red and white paper, partly handwritten]. Type locality: Sitka, Alaska. Examined, including genitalia.

Peryphus tetraglyptus Mannerheim, 1853: 151 . Lectotype male, designated by Lindroth (1963: 273), in ZMH.

Bembidion blanditum Casey, 1918: 23 . Lectotype female, designated by Lindroth (1975: 116), in USNM, labelled ‘Metlakatla B. Col. Keen’ [white paper], ‘CASEY bequest 1925’ [white paper], ‘blandita Csy.’ [white paper, handwritten], ‘TYPE USNM 36829’ [red paper], ‘ LECTOTYPE blanditum Csy. By C.H. Lindroth’ [white paper, partly handwritten]. Type locality: Metlakatla, British Columbia. Examined.

Nomenclatural notes: Lindroth’s concept of ‘ Bembidion incertum ’, as a widespread species distributed from the Pacific states to Colorado, included this species, B. ampliatum , B. lividulum and B. saturatum .

Diagnosis: A small-bodied, convex species with strongly foveate dorsal punctures. Forebody dark brown, hindbody dark brown or reddish brown, often lighter than forebody; forebody and hindbody commonly with a metallic hue. Pronotum with fairly rounded lateral margin, widest at middle or just anterior to middle; laterobasal carina strong but often short (not proceeding far anteriorly) due to convexity of pronotum; basal fovea deep; hind angles slightly obtuse ( Fig. 11C). Elytral striae generally pronounced and dorsal punctures strongly foveate; elytra fairly short relative to length of pronotum ( Fig. 1C). Microsculpture with meshes moderately etched in both sexes ( Fig. 13A) (but note geographic variation below). Male genitalia with medium-length flagellum; sclerite ‘St’ more or less diamond-shaped ( Figs 8E, F, 10C).

Comparison with similar species: Most easily confused with B. lividulum , B. saturatum and B. vulcanix . Distinguished from B. lividulum by having more convex pronotum and elytra with somewhat rounded lateral margin of elytra, pronotum widest closer to middle, and male genitalia with a longer, more sinuate flagellum and broader sclerite ‘St’. Distinguished from B. saturatum and B. vulcanix by having a slightly smaller body size, more rounded lateral margin of elytra that narrows at the shoulder and more strongly foveate dorsal punctures, with pronotum larger relative to elytra and with a short laterobasal carina, and male genitalia with a shorter flagellum.

Geographic distribution: The northernmost species, ranging from the Aleutian Islands south along the coastal mountains of British Columbia , and in the Cascades of Oregon and Washington , south throughout California in the Sierra Nevada ( Fig. 14B) . Also known from one locality in Yoho National Park in eastern British Columbia .

Habitat: Most common on small, subalpine creeks in the southern part of its range. In the north, it occurs along creeks, rivers or open slopes at high elevation.

Geographic variation: Some specimens are larger-bodied in the Sierra Nevada with broader pronota relative to northern localities. Notable intraspecific variation (in body size, pronotum shape, forebody and elytral coloration) is present in northern populations (e.g. southeast Alaska). Microsculpture shape and intensity is variable; in particular, some specimens may have notably transverse meshes (e.g. Queen Charlotte Islands, British Columbia), or less deeply etched meshes such that portions of cells are partially disappeared in males (e.g. Snoqualmie Pass, Washington). Some individuals from Yoho National Park are notably small in size .