Epeolus axillaris, Onuferko, Thomas M., 2018

Onuferko, Thomas M., 2018, A revision of the cleptoparasitic bee genus Epeolus Latreille for Nearctic species, north of Mexico (Hymenoptera, Apidae), ZooKeys 755, pp. 1-185 : 28-31

8. Epeolus axillaris sp. n. Figs 18, 19, 94A

Epeolus scopulus Brumley, 1965. M.S. thesis, Utah State University, Logan 66 (♀) [nomen nudum].

Diagnosis.

Epeolus axillaris can be differentiated from all other Epeolus species in North America by the distinct posteromedial depression of the metanotum; in all other species the metanotum is flat, strongly convex, or weakly convex. Epeolus axillaris closely resembles E. banksi , E. minimus , and E. olympiellus in that the axilla (except sometimes the tip) and mesoscutellum are black; T1 has a quadrangular discal patch, in dorsal view the longitudinal band is at least half as wide as the breadth of the apical fascia; and the T2 fascia has lobe-like anterolateral extensions of tomentum. However, in all three species the metanotum is flat and the axilla does not extent much beyond the midlength of the mesoscutellum, whereas in E. axillaris the axilla is more elongate, extending well beyond the midlength of the mesoscutellum but not as far back as its posterior margin.

Description.

FEMALE: Length 10.0 mm; head length 2.1 mm; head width 2.9 mm; fore wing length 6.9 mm.

Integument coloration. Mostly black; notable exceptions as follows: partially to entirely ferruginous on mandible, antenna, pronotal lobe, tegula, axilla, legs, T5, and pygidial plate. Mandible with apex darker than all but extreme base; preapical tooth slightly lighter than mandibular apex (difficult to see in holotype because mandible closed; described from paratypes). Flagellum brown and (except F1) slightly lighter than partially dark brown (otherwise orange) scape, pedicel, and F1, primarily due to extensive pilosity on flagellum. Axilla only with tip orange. Pronotal lobe and tegula pale ferruginous to amber. Wing membrane subhyaline, apically dusky. Legs, except reddish-orange mesotibia, metatibia, and tarsi, with brown or black more extensive than reddish orange.

Pubescence. Face with tomentum densest around antennal socket. Dorsum of mesosoma and metasoma with bands of off-white to pale yellow short appressed setae. Mesoscutum with paramedian band wider and joined posteriorly. Mesopleuron densely hairy, except for two sparsely hairy circular patches (one behind pronotal lobe, a larger one occupying much of ventrolateral half of mesopleuron). Metanotum with tomentum uninterrupted except for median bare patch in posterior half, uniformly off white. T1 with median quadrangular black discal patch enclosed by pale tomentum, except for medial separation at apex. T2-T4 with fasciae interrupted medially and narrowed before becoming somewhat broader laterally, T2 with fascia with anterolateral extensions of equally dense tomentum. T5 with two patches of pale tomentum bordering and separate from pseudopygidial area. T5 with pseudopygidial area lunate, its apex more than twice as wide as medial length, indicated by silvery setae on impressed disc of apicomedial region elevated from rest of tergum. S5 with apical fimbria of coppery to silvery hairs extending beyond apex of sternum by ~2/5 MOD.

Surface sculpture. Punctures dense. Labrum with larger and sparser punctures (i=1-2d) than clypeus (i<1d). Small impunctate shiny spot lateral to lateral ocellus. Mesoscutum, mesoscutellum, and axilla coarsely and densely rugose-punctate. Tegula very densely punctate mesally (i<1d), less so laterally (i=1-2d). Mesopleuron largely obscured by tomentum, but ventrolateral half densely punctate (i<1d) to rugose where exposed; mesopleuron with punctures more or less equally dense throughout where exposed. Metasomal terga with punctures very fine, dense (i≈1d), evenly distributed on disc.

Structure. Labrum with pair of small subapical denticles, each preceded by small discrete longitudinal ridge. Frontal keel not strongly raised. Scape with greatest length 1.7 × greatest width. F2 noticeably longer than wide (L/W ratio = 1.4). Preoccipital ridge not joining hypostomal carina, from which it is separated by about 1.5-2 MOD at its terminal. Mesoscutellum moderately bigibbous. Axilla large, its lateral margin (L) half as long as mesoscutellar width (W) (L/W ratio = 0.5) and tip extending well beyond midlength of mesoscutellum but not as far back as its posterior margin; axilla with tip conspicuously diverging from side of mesoscutellum, distinctly hooked, and axilla with free portion 2/5 its medial length; axilla with lateral margin relatively straight and without carina. Metanotum with posteromedial depression beneath overhanging anterior portion. Fore wing with three submarginal cells. Pygidial plate apically truncate.

MALE: Description as for female except for usual secondary sexual characters and as follows: F2 shorter, not noticeably longer than wide (L/W ratio = 1.1); S4 and S5 with much longer coppery to silvery subapical hairs; pygidial plate apically rounded, with large deep punctures more or less evenly spaced throughout, with the interspaces shining.

Etymology.

The name is in reference to the axillae of this species, which are distinctly longer than those of the similar E. minimus and E. olympiellus .

Distribution.

California and western Nevada. According to Brumley (1965), this species also ranges into Oregon, but its presence in that state could not be verified in the present study (Fig. 19).

Ecology.

HOST RECORDS: The host species of E. axillaris is/are presently unknown.

FLORAL RECORDS: Labels of examined voucher specimens indicate floral associations with Chrysothamnus Nutt. ( Compositae ) (possibly in reference to plants that now are in the genus Ericameria Nutt. ( Compositae )), Ericameria nauseosa var. nauseosa (Pall. ex Pursh) G.L. Nesom & Baird, E. nauseosa var. oreophila (A. Nelson) G.L. Nesom & Baird, and E. parryi (A. Gray) G.L. Nesom & Baird.

Discussion.

This species is most similar to E. minimus and E. olympiellus , and there is overlap in the ranges of all three species. Brumley (1965) recognized E. axillaris as a separate species in which the axilla is more elongate and the metanotum is uniquely depressed posteromedially. The morphological distinction is supported by molecular data, as sequenced specimens exhibiting these attributes were assigned a separate BIN from either of the other two species.

Material studied.

Type material. Primary: USA: Nevada: Cottonwood Creek (38.6013°N; 118.8280°W) (Mineral County), 14.viii.1998, F.D. Parker (holotype ♀ [CCDB-28237 D01], BBSL).

Secondary: USA: California: Antioch (Contra Costa County), x.1938, J.A. Downes (paratype ♂, CNC), 10.ix.1947, P.D. Hurd (paratype ♂, BBSL), 10.ix.1947, U.N. Lanham (paratype ♀, CUM); Bodie (Mono County), 21.ix.1958, A.S. Menke and L.A. Stange (paratype ♀, LACM); Hot Creek (Mono County), 29.viii.1969, E.E. Grissell (paratypes 3♀, UCBME), 29.viii.1969, R.M. Bohart (paratype ♂, UCBME); Parker Creek at Walker Lake Road (37.8768°N; 119.1203°W) (Mono County), 02.ix.2009, G.R. Ballmer (allotype ♂ [CCDB-28313 H10], UCR), 02.ix.2009, G.R. Ballmer (paratypes 2♂ (1 barcoded [CCDB-28313 H08]), UCR); Upper Santa Ana River (San Bernardino County), 22.ix.1946, G.H. and J.L. Sperry (paratype ♂, KUNHM); Nevada: 17 mi N Sparks (Washoe County), 02.ix.1957, E.G. Linsley (paratype ♀, BBSL), 02.ix.1957, E.G. Linsley (paratype ♀, USNM); 3 mi N Minden (Douglas County), 10.ix.1957, R.C. Bechtel (paratype ♀, AMNH); Reno, 09.ix.1961, F.D. Parker (paratype ♂, UCBME).

DNA barcoded material with BIN-compliant sequences.

Available. BOLD:ACZ2412. See Type material for specimens examined and sequenced (indicated by unique CCDB-plate and well number).