Atheta (Hydrosmectomorpha) vincenti Webster and Klimaszewski, new species

(Fig. 24–31)

Holotype (male). Canada, New Brunswick, Saint John Co., Fundy Trail Parkway, 45.4226°N, 65.4055°W, 16.VIII.2009, R.P. Webster, coll. // Big Salmon River, river margin among algae-covered gravel and cobblestones, sun-exposed area, (CNC) . Paratypes. Canada, New Brunswick, Saint John Co., Fundy Trail Parkway, 45.4226°N, 65.4055°W, 16.VIII.2009, R.P. Webster, coll. // Big Salmon River, river margin among algae covered gravel and cobblestones, sun-exposed area (LFC) 1 female, (RWC) 3 males, 5 females ; New Brunswick, Carleton Co., Belleville, Meduxnekeag Valley Nature Preserve, 46.1897°N, 67.6781°W, 31.VII.2009, R.P. Webster, coll. // Rich Appalachian hardwood forest, margin of shaded spring-fed brook among gravel on firm sand/clay/gravel mix (RWC) 1 male ; New Brunswick, Madawaska Co., Baker Brook, 47.29719°N, 68.51226°W, 26.VII.2006, R. Capozi & R. Webster, coll. // Saint John River island, among cobblestones near water (RWC) 1 male, 1 female .

Etymology. This species is named in honor of Vincent Webster who collected many aleocharine specimens in New Brunswick representing new taxa and new provincial records as well as many other new records from other families.

Diagnosis. Body subparallel, flattened, length 3.2–3.8 mm; colour dark brown to almost black, with legs and elytra, except for scutellar region, paler, yellowish-brown (Fig. 24); integument moderately glossy, forebody with fine, moderately dense punctation and faint meshed microsculpture; head slightly narrower than pronotum, eyes large and slightly protruding; antennae moderately robust, all antennomeres distinctly elongate (Fig. 24); pronotum widest at apical third (0.59 mm), (Fig. 24); elytra flat- tened, distinctly elongate, at suture about as long as pronotum, broader than pronotum (0.73 mm at shoulders); abdomen subparallel, widest at apical third. Male. Apical margin of tergite VIII obliquely produced laterally, with two lobe-like processes forming a variable, obtuse angular emargination medially (Fig. 26); sternite VIII moderately deeply emarginate, apical margin broadly truncate, rounded laterally (Fig. 27); tubus of median lobe of aedeagus in lateral view moderately wide, ventral margin straight to apical third, then moderately curved ventrad to narrow apex (Fig. 25). Female. Apical margin of tergite VIII obtusely produced laterally, truncate medially (Fig. 28); apical margin of sternite VIII obliquely produced, broadly rounded apically (Fig. 29); spermatheca short, capsule club-shaped with shallow apical invagination, stem narrow and straight or slightly sinuate (Fig. 30, 31).

Distribution. Origin: Nearctic. CANADA: NB.

Habitat and collection data. Habitat. Most specimens are from a cobblestone river margin (clear, fast flowing medium-sized river). Adults were found among algae-covered gravel and cobblestones in a sun-exposed area near flowing water. A few were collected from among cobblestones along a large river; one individual was collected from the margin of a shaded spring-fed brook among gravel on firm sand/ clay/gravel mix flowing into the Meduxnekeag River. Collecting period. VII–VIII. Collecting method. Hand collecting from among cobblestones near rivers and streams.