Osmia (Diceratosmia) exquisita, Griswold & Rightmyer, 2017

Rightmyer, Molly G., 2017, A revision of the subgenus Osmia (Diceratosmia), with descriptions of four new species (Hymenoptera, Megachilidae), Zootaxa 4337 (1), pp. 1-37 : 8-11

Osmia (Diceratosmia) exquisita new species

( Figs 1D , 9B )

Diagnosis. Females of O. exquisita are readily distinguished from all other Diceratosmia except O. azteca by their large size (intertegular distance ca. 3.5 mm), reddish golden scopa ( Fig. 9B ), and small projection on the apical tip of S6. Females of O. exquisita have blue integument on the face and brassy green on the remainder of the body, while in O. azteca the integument is very dark brown to black. Osmia exquisita and O. azteca are additionally distinguished by characters of the mandible and S6 (see Diagnosis under O. azteca ).

The male of O. exquisita is unknown, but is expected to differ from other Diceratosmia by the combination of its large size and metallic green integument. Osmia azteca is the only other known Diceratosmia with such a large size, but in O. azteca the integument is dark brown to black rather than metallic blue or green.

Description. Female. Total length: ca. 15 mm; forewing length: 10 mm; distance between lateral ocellus and preoccipital margin: 1.3 mm; distance between lateral ocellus and compound eye: 0.7 mm.

Color: Royal blue on face and lower gena; brassy green with dull, grayish blue inflections on vertex, upper gena and remainder of body, except as follows: orange-brown integument on mouthparts, antenna distal to F3, posterior three-fourths of tegula, tarsi; dark brown on antenna basal to F3, mid and hind legs between trochanters and tarsi, apical margins of T4–T6; black on mandible, apical edge of clypeus. Forewing more strongly infuscate than hindwing.

Pubescence: Hairs entirely golden to reddish golden, except brown on wings. Labrum with long hairs along subapical margin (surface of labrum not visible, unable to determine if additional fringe at approximate midpointis present). Clypeus below apical margin with lateral tuft of reddish golden, medially directed hairs. Mandible on apical half above outer ridge with dense, golden, stout, spatulate, appressed hairs, on ventral margin with hairs relatively long and sparse. Hypostomal area with straight, branched hairs evenly distributed across area. Head with hairs mostly minutely branched, nearly simple, except more distinctly plumose hairs on paraocular area, frons above paraocular area, lower gena, and hypostomal area; simple hairs on mouthparts and labrum, and stout, simple hairs on apical half of mandible above outer ridge. Mesosoma, excluding legs and wings, with hairs mostly minutely branched to plumose, except mostly simple on ventral surface of mesepisternum. Legs with hairs on outer surfaces pale golden except darker reddish golden on inner surfaces of tibiae; femora outer surfaces with hairs relatively slender and minutely branched or simple; tibiae and tarsiouter surfaces with hairs mostly simple, hindbasitarsus with hairs appressed, simple, relatively stout. Wing membranes with short, dense, evenly distributed, simple hairs. Scopa reddish golden, with hairs tapered at apical tips.

Punctation: Head and mesosoma with punctures nearly contiguous, round, strongly impressed except as follows: labrum mostly impunctate; clypeus with medioapical truncation impunctate for length of F1 or slightly less; supraclypeal area with punctures separated by up to one puncture diameter; vertex with impunctate line posterior to median ocellus; mesoscutum immediately posterior to median longitudinal sulcus with punctures separated by up to one puncture diameter; hypostomal area anteriorly, pronotum, propodeum, and legs with punctures shallowly impressed, sometimes elongated into oval shape; tegula with punctures minute, dense at anterior third and at outer margin, sparse medially and posteriorly (separated by up to eight puncture diameters); propodeum near propodeal pit with punctures sparse and integument shiny; propodeal triangle with dorsal fourth moderately reticulate to lineate, lower three-fourth strongly shiny, glabrous (sometimes weakly shagreened immediately below reticulate area medially). T1 anterior surface shiny. Metasomal terga with dorsal surfaces (excluding impunctate apical margins) dull, densely punctate, punctures nearly contiguous to separated by one puncture diameter. T1–T2 apical impunctate bands relatively narrow laterally, ca. one puncture diameter in length or less, medially with impunctate bands widened, up to four puncture diameters in length at exact midpoint. T3–T5 with apical impunctate bands laterally 1–2 puncture diameters in length; medially 3–4 puncture diameters in length. T6 apical impunctate band well defined, ca. 4–5 puncture diameters in length.

Structure: Maxillary palpus four-segmented; second labial palpal segment ca. 1.3x longer than basal segment. Mandible ( Fig. 1D ) with outer and condylar ridges of subequal thickness or with condylar ridge slightly thicker, parallel along length; apical margin with four teeth, third poorly separated from second and fourth by very weak carina, margin of third tooth forming distinct V-shape with adjacent margin of second and very weakly curved Ushape with adjacent margin of fourth, third tooth weakly set back from second and fourth; inner, ventral margin of mandible lacking distinct tooth, diverging well away from condylar ridge towards inner, dorsal margin of mandible; mandible with basal half of ventral margin distinctly carinate; mandible apically widened (1.7 times wider than median width), first tooth length much longer than second (dorsal margin of first tooth twice length of ventral margin of second), second tooth located slightly closer to fourth tooth than first. Clypeus with apical margin forming slightly scoop-shaped truncation (in oblique view), apical margin linear or weakly concave along truncation and forming ca. 130 degree angle with lateral apical margin of clypeus. F1 one-half longer than F2 length or slightly less, remaining apical flagellar segments gradually increasing in length such that F10 ca. onefourth longer than F1 length. Vertex behind lateral ocellus ca. 5.0 OD in length or slightly less. Genal width ca. 1.3 times compound eye width in lateral view. Preoccipital margin angled but not distinctly carinate. Hypostomal carina moderately high, highest at about midpoint of hypostomal area posterior to angle, not forming triangular projection at this point but forming distinct, semicircular projection, tapering to low carina or near obsolescence at angle. Mesepisternum with omaulus broadly rounded, not approaching carinate. Scutellum on anterior margin straight, not gently biconvex. Malus forming long, pointed apical spine, this spine minutely pectinate on inner margin. Foretarsi excluding basitarsus and apical-most segment with lobes moderately to weakly swollen, anterior lobes slightly longer than posterior. Hindtibial spurs more or less straight along length to weakly curved on apical sixth, outer spur about one fifth shorter than inner. Hind basitarsus with lateral margins of outer surface nearly parallel, sub-basally slightly wider than apically. T1 anterior and dorsal surfaces separated by weak carina.

Male. Unknown.

Distribution. Known only from Comayagüela, Francisco Morazán, Honduras ( Fig. 18 ).

Floral Associations. None.

Type Material. Holotype female. “HONDURAS Fran. Mor. [Francisco Morazán] Comayaguela 1–31 Oct 1995 B. J. Hull// Osmia (Diceratosmia) n. sp. 4 ♀ T. Griswold det.// HOLOTYPE Osmia exquisita Griswold & Rightmyer ♀ HOLO76 [red label]” (LOGAN). Paratype. HONDURAS, Francisco Morazán, Comayagüela, 1–31 October 1995, B. J. Hull (1♀, LOGAN).

Etymology. This species is named after the Latin word “exquisitus”, meaning elegant or fine, in reference to the overall beauty of this bee.

Figures

FIGURE 1. Female mandibles: A) O. marilaunidii (DRO 0115730), B) O. azteca (34211), C) O. conjunctoides (BBSL 204519), D) O. exquisita (BBSL 989169). Scale bar = 0.25 mm.

FIGURE 9. Female habitus lateral view: A) O. azteca (BBSL 839523), B) O. exquisita (BBSL 989169). Scale bar = 0.5 mm.

FIGURE 18. Known distributions of O. conjunctoides (green triangles), O. exquisita (white circles), O. gonzalezi (red circles), O. lacunosa (yellow circles), O. spinulifera (blue circles), and O. stangei (purple triangles). Scale bar = 200 km.