Osmia Melanosmia aquilonaria Rightmyer, Griswold, & Arduser

Rightmyer, Molly G., Griswold, Terry & Arduser, Michael S., 2010, A review of the non-metallic Osmia (Melanosmia) found in North America, with additional notes on palearctic Melanosmia (Hymenoptera, Megachilidae), ZooKeys 60, pp. 37-77 : 38-45

Osmia Melanosmia aquilonaria Rightmyer, Griswold, & Arduser sp. n. Figs 1, 21332

Diagnosis.

Males of Osmia aquilonaria are most similar to the palearctic species Osmia svenssoni and Osmia steinmanni , but can be differentiated from them by the shape and pilosity of S4 and gonoforceps (See Table 2). Osmia aquilonaria males can be distinguished from all other members of the inermis species group (except Osmia svenssoni and Osmia steinmanni ) by the special form of the hairs on S4 (i.e., with two patches of hooked bristles both along apical margin and on premarginal area, along apical margin the bristles oriented horizontally and on premarginal area directed increasingly vertically, Figs 24, 25).

Females of Osmia aquilonaria can be distinguished from the only other nearctic member of the inermis species group, Osmia laticeps , by the more pointed third tooth and the parallel condylar and outer ridges of the mandible (Figs 1, 2; Osmia laticeps with third tooth forming cutting edge extending from fourth tooth, and with apically converging condylar and outer ridges, Figs 5, 6). Females of Osmia aquilonaria are extremely similar to those of the palearctic Osmia svenssoni , and are not readily differentiated from them other than by their respective geographic distributions.

Description.

Female. Figs 1, 2, 13-18. Total length: 8.2-11.0 mm; forewing length: 6.4-6.8 mm; length of lateral ocellus to preoccipital margin 0.7 mm; length of lateral ocellus to compound eye 0.6-0.7 mm.

Color: Dark brown to brown-black, sometimes with reddish overtones especially on mouthparts, labrum, mandible, flagellar segments, legs, and apical margins of T1-T5. Wings mostly clear to weakly infuscate, except strongly infuscate along leading edge of forewing, especially along dorsal half of marginal cell.

Pubescence: Clypeus below apical margin with lateral tuft of golden, medially directed hairs. Dark brown, minutely branched hairs on most of body except as follows: pale golden to white, minutely branched hairs interspersed with brown on interantennal area, vertex, posterior surface of propodeum excluding triangle, and dorsal surfaces of T1, T2, T6; almost entirely pale golden to white, minutely branched hairs on mesoscutum, mesoscutellum, and metanotum; dark-brown, simple hairs interspersed with minutely branched hairs on most of body, except simple hairs lacking on dorsal mesosoma; dark-brown, simple hairs only (no branched hairs) on all tarsi and scopa; brown, short, simple hairs evenly covering forewing. Galea and basal two labial palpal segments with hairs on lateral margins straight, 0.2-0.5 OD in length. Labrum with long hairs arranged in two curved, transverse rows, along subapical margin and approximately at midpoint, with additional fringe of shorter hairs at apical margin. Clypeus with hairs about as dense as on frons. Hypostomal area with hairs evenly distributed across area, straight to slightly wavy at apical tips, 2.5-4.0 OD in length.

Punctation: Head and mesosoma with punctures nearly contiguous, more or less round, and moderately impressed except as follows: labrum mostly impunctate; clypeus with impunctate midapical truncation about length of F2 or little longer (Fig. 15); mesoscutum immediately posterior to median longitudinal sulcus with punctures separated by up to two puncture diameters; mesepisternum with punctures separated by about half a puncture diameter; hypostomal area, pronotum, and legs with punctures shallowly impressed, sometimes elongated into oval shape; tegula with punctures minute, sparse medially and posteriorly, separated by up to four or five puncture diameters; metepisternum, metanotum, and lateral and posterior surfaces of propodeum with punctures very weakly impressed, with background integument strongly granulose, dull; propodeal triangle with dorsal fourth finely areolate to lineate, lower three fourths strongly granulose, dull (Fig. 16). T1 anterior and dorsal surfaces, and T2-T5 strongly shagreened, dull, with small, sparse punctures throughout except for apical margins, these punctures with integument anterior to them slightly raised, papillate; T1-T5 apical impunctate bands with length at midpoint about 4.0-6.0 puncture diameters or little more (Figs 17, 18).

Structure: Labial palpus four-segmented, second labial palpal segment ca. one-third longer than basal-most segment. Mandible with outer and condylar ridges of subequal thickness, parallel along length to very weakly converging apically (Fig. 1); apical margin with four strongly pointed teeth, third separated from second and fourth by carina, margin of third tooth forming distinct V-shape with adjacent margin of second and slightly smaller V-shape with adjacent margin of fourth, third tooth set back from second and fourth, very slightly directed inwards (Fig. 2); inner, ventral margin of mandible lacking distinct tooth, slightly diverging away from condylar ridge basally; mandible apically widened (1.3 times wider than median width), first tooth slightly longer than other teeth, length between apical tips of second and fourth teeth slightly wider than (ca. 1.2 times) apical tips of first and second teeth (Fig. 2). Clypeus with apical margin linear to moderately emarginate medially, with entire apical truncation laterally more or less contiguous with remaining lateral margin of clypeus (not forming 90 degree angle with lateral apical margin of clypeus; Fig. 15). F1 twice length of F2 or slightly more, remaining apical flagellar segments gradually increasing in length such that F10 subequal to F1 or little longer. Vertex behind lateral ocellus 2.5-3.0 OD in length. Genal width 1.5 to nearly 2.0 times that of compound eye in lateral view. Preoccipital margin rounded, not carinate. Hypostomal carina moderately high, highest at about midpoint of hypostomal area posterior to angle and sometimes forming moderate triangular projection at this point, tapering to low carina or near obsolescence at angle. Malus forming pointed apical spine, this spine more or less a continuation of nearby edge of vellum. Foretarsal segments excluding basitarsal and apical-most segments with anterior lobes slightly longer than posterior. Midtarsal segments with anterior and posterior lobes of equal width, slightly swollen; hind tarsal segments not swollen. Hind tibial spurs strongly curved at apical tips, outer spur about one fifth shorter than inner. Hind basitarsal segment with lateral margins of outer surface parallel.

Male. Figs 19-32. Total length: 9.5 mm (8.2-9.5 mm); forewing length: 6.3 mm (5.9-6.3 mm); length of lateral ocellus to preoccipital margin 0.5 mm (0.4-0.5 mm); length of lateral ocellus to compound eye 0.5 mm.

Color: Black to dark brown, sometimes with reddish overtones especially on mouthparts, labrum, mandible, flagellar segments, legs, and apical margins of T1-T6 and S1-S3. Wings mostly clear except weakly infuscate along leading edge of forewing, especially along dorsal half of marginal cell.

Pubescence: White to golden, minutely branched hairs on body except golden to pale golden, stouter hairs on inner surfaces of tarsi, S4, and S6. Labrum covered with hairs on apical third and with hairs forming short fringe at apical margin. S2 with hairs at apical third relatively long (ca. 3.0 OD). S3 with dense, medially directed hairs filling entire emargination (hairs ca. 1.0 OD in length medially, nearly 2.0 OD laterally) (Fig. 24). S4 midapical truncation with two patches of dense, golden, distally hooked hairs, these patches of hairs medially interrupted by nearly 1.0 OD, with hairs distally meeting at midpoint, each patch along apical margin with hairs oriented horizontally and on premarginal area directed increasingly vertically (Figs 24, 25). S6 midapical truncation sparsely covered with short, distally hooked hairs arising from papillate bases (Fig. 28).

Punctation: Head with punctures ovate to nearly circular, separated by one-fourth to one-half puncture diameter and deeply impressed except as follows: labrum mostly impunctate on basal two-thirds; clypeus with impunctate band along apical margin, about one-third length of F1 in length; disc of clypeus, interantennal area, and paraocular area with punctures small, ovate, and nearly contiguous (punctures mostly obscured beneath dense hairs); hypostomal area anteriorly near angle with punctures weakly, shallowly impressed. Mesosoma with punctures more or less round, nearly contiguous to separated by up to a half puncture diameter, deeply impressed except as follows: mesoscutum immediately posterior to median longitudinal sulcus with pun ctures separated by up to one, sometimes as much as three puncture diameters; tegula with punctures minute, sparse medially, separated by up to eight to ten puncture diameters; pronotum, metepisternum and lateral and posterior surface of propodeum strongly shagreened, with weakly, shallowly impressed, larger punctures; metanotum and propodeal triangle strongly granulose, dull (Fig. 21); propodeal triangle lineolate on dorsal fifth; legs with inner surfaces of trochanters, femora, and tibiae shining, with scattered smaller punctures. T1 with anterior surface strongly shagreened, dull; metasomal terga with dorsal surfaces excluding apical margins strongly shagreened, apical impunctate margins moderately to weakly shagreened (except T7 moderately polished). T1 dorsal surface with punctures minute, moderately distinct and well-impressed, separated from 1.0 to 3.0 puncture diameters; apical impunctate margin medially ca. 10.0 puncture diameters in length, laterally as little as 6.0 puncture diameters. T2-T7 with punctures minute, T2 with punctures separated by ca. 1.0 puncture diameter medially (sparser towards impunctate apical margin on all terga), successively posterior terga with punctures progressively becoming more widely spaced to about 3.0 puncture diameters apart on disc of T7; T2-T6 with apical impunctate margins 6.0-9.0 puncture diameters in length, T7 with apical impunctate margin 4.0-6.0 puncture diameters in length. S1-S3 with punctures weakly, shallowly impressed. S4 with integument granular, dull (Fig. 24). S5-S6 lacking distinct punctures, weakly shagreened.

Structure: Mandible with outer and condylar ridges converging apically; apical margin with two teeth, upper tooth distinctly shorter and slightly wider than lower, upper tooth with inner and dorsal margins forming ca. 70-80 degree angle; inner, ventral margin of mandible weakly diverging away from condylar ridge basally. Clypeus apical margin with irregular tubercles, lacking distinct apical truncation. Flagellar segments subequal in length, except F1 about three-fourths length of F2 and F11 slightly longer than other segments. Vertex behind lateral ocellus 2.0 OD in length or nearly so. Genal width subequal that of compound eye in lateral view (slightly wider dorsally). Preoccipital margin rounded, not carinate. Hypostomal carina moderately high, gradually tapering to near obsolescence at angle, not forming distinct tooth. Malus forming small but distinct apical spine. Foretarsal segments excluding basitarsal and apical-most segments with lobes slightly, equally swollen. Mid- and hind tarsal segments not swollen. Hind tibial spurs curved at apical fifth, outer spur slightly shorter than inner. Hind basitarsal segment with lateral margins of outer surface weakly diverging apically, with strong tooth on inner margin (Fig. 22). T6 midapically with small but usually distinct emargination, forming ca. one-fourth to one-half of circle in outline (Fig. 23); T6 lateroapical margin smoothly, weakly convex, not forming distinct tooth. T7 midapically strongly emarginate, forming semicircle about as wide as deep (ca. 0.5-0.8 OD wide), with spines on either side of emargination weakly pointed, basally nearly as wide as emargination width (Fig. 23). S2 evenly convex, covering most of S3. S3 with midapical emargination relatively wide and shallow (half entire width of sternum, 1.0 OD in length, measuring only apical margin of sternum and not including basal fringe of hairs; Fig. 24). S4 midapically with wide truncation (about half width of entire sternum), medially with shallow but distinct emargination between lateral tufts of hairs (Fig. 24). S5 with apical margin evenly, strongly concave along median half of margin. S6 with strong midapical truncation, slightly less than one-third width of sternum, truncation slightly wider than deep, apical margin of truncation weakly, evenly rounded apically, sometimes with small emargination medially (Fig. 28). S8 as in Fig. 29. Gonoforceps weakly narrowed apical to subapical bend in dorsal, ventral, and lateral views (Figs 26, 27, 30-32).

Distribution.

Alaska and Northwest Territories south to Wyoming, and east across Canada to Nova Scotia.

Holotype male.

"[Canada] N.W.T. [Northwest Territories] km 491, Dempster Hwy, 26.VI.80 [26 June 1980], 1000 m, Wood & Lafontaine// Osmia svenssoni Tkalcu ♂ T Griswold det 96// Holotype male Osmia aquilonaria Rightmyer, Griswold, & Arduser" (Ottawa)

Paratypes.

CANADA: NORTHWEST TERRITORIES, Inuvik Region, Aklavik, 25 June 1931, O. Bryant (1♀, Logan), 25 July 1931, 1600 ft (1♀, San Francisco); Black Mountain, SW of Aklavik, 1 August 1931, O. Bryant (1♀, 1♂, Logan); Holman, Victoria Island, 25 June 1952, B. A. Gibbard (1♀, Ottawa); NOVA SCOTIA, Cape Breton Highlands National Park, 60˚50'W 46˚47'N, 22 June 1983, Birch (1♀, Ottawa); NUNAVUT, Kitikmeot Region, Coppermine, 3 August 1951, S. D. Hicks (1♀, Ottawa); ONTARIO, Cochrane District, Low Bush, Lake Abitibi, 5 June 1925, N. K. Bigelow (1♀, St. Charles), 18 June 1925, N. K. Bigelow (1♀, St. Charles); Thunder Bay District, Silver Island, Sibley Peninsula, 18 July 1961, Rubus sp., H. E. Milliron (1♀, Ottawa); QUEBEC, Nord-du-Québec Region,Highway to James Bay km 66, 50˚03'N 77˚07'W, 12 June– 8 August 1987, Malaise-FIT Salix bushes, L. Leblanc (1♀, Ottawa); YUKON, Dempster Highway km 465, 23-25 June 1980, 800 m, Wood & Lafontaine (2♀, Ottawa); USA: ALASKA, North Slope Borough, Cape Thompson, 29 June 1961, B. S. Heming (1♀, Ottawa); Yukon-Koyukuk Census Area, Kathul Mountain, Yukon River, Steppe, 4 June 1991, Arnica alpina , J. A. Bishop (1♀, Davis), 5 June 1991, Lupinus arcticus (1♀, Davis); Kathul Mountain, Yukon River, 110 km NW Eagle, Tundra, 16 June 1992, Lupinus arcticus , J. A. Bishop (1♀, Davis); WYOMING, Fremont Co., Roaring Fork Mountain, Wind River Range, 29 June 1990, 11000-1200 ft, E. A. Sugden (6♀, 3♂, Logan).

Etymology.

The name “aquilonaria” is Latin, meaning northern or northerly, and is in reference to the northern distribution of the species in North America.