Epeolus nebulosus, 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 : 120-122

34. Epeolus nebulosus sp. n. Figs 71, 72, 99A

Diagnosis.

The following morphological features in combination (excluding any that are specific to the opposite sex of the one being diagnosed) can be used to tell E. nebulosus apart from all other North American Epeolus except E. basili , E. novomexicanus , and E. pusillus : the axilla is large, with the tip extending well beyond the midlength of the mesoscutellum but at most to the band of pale tomentum along its posterior margin, dilated laterally, and ferruginous to some degree whereas the mesoscutellum is typically all black; the axilla’s free portion is clearly less than 2/5 as long as its entire medial length; the mesopleuron is closely (most i<1d) and evenly punctate, that of the female is obscured by white tomentum only in the upper half (with a large, sparsely hairy circle occupying much of the ventrolateral half) whereas that of the male (excluding the hypoepimeral area) is entirely obscured by white tomentum; T2-T4 have complete and evenly broad fasciae; the T2 fascia has lobe-like anterolateral extensions of tomentum; and the pseudopygidial area of the female is lunate and wider than long (the apex ≤2 × the medial length). Epeolus basili , E. nebulosus , E. novomexicanus , and E. pusillus are all extremely similar to one another. Epeolus nebulosus is most similar to E. novomexicanus , but in E. novomexicanus the mesoscutum usually has distinct paramedian bands and at least the integument beneath the T1 apical fascia is ferruginous, as are sometimes the rest of the tergum and other terga, whereas in E. nebulosus the mesoscutum is entirely obscured by pale tomentum and the metasomal terga (excluding the brown translucent apical margins) are entirely black. In E. basili the metasomal terga are also ferruginous to some degree, and the T2 and T3 (for female) or T2-T4 (for male) fasciae are narrowed medially and removed from the apical margin (in E. nebulosus the T2-T4 fasciae are on or very little removed from the apical margin), and the pseudopygidial area of the female is ≥2 × the medial length. Whereas in E. pusillus the flagellum, except sometimes F1, and metasomal sterna are consistently brown or black and clearly not the same reddish-orange color as the legs (tibiae to tarsi), in E. nebulosus the flagellum, at least ventrally, is the same reddish-orange color as the legs (tibiae to tarsi) as are usually the metasomal sterna. Epeolus nebulosus is also similar to E. scutellaris in that the axilla is large, with the lateral margin arcuate, and that the apical fasciae are complete. However, in E. scutellaris the pseudopygidial area of the female is much wider (the apex ~2.5-3 × the medial length) than in E. nebulosus , and the mesopleuron of both the female and male is obscured by white tomentum only in the upper half (with a large, sparsely hairy circle occupying much of the ventrolateral half).

Description.

MALE: Length 7.2 mm; head length 2.0 mm; head width 2.7 mm; fore wing length 5.5 mm.

Integument coloration. Mostly black; notable exceptions as follows: at least partially ferruginous on mandible, antenna, pronotal lobe, tegula, axilla, legs, pygidial plate, and metasomal sterna. Mandible with apex darker than rest of mandible; preapical tooth slightly lighter than mandibular apex. Antenna brown and orange in part. Pronotal lobe and tegula pale ferruginous to amber. Wing membrane subhyaline, apically dusky. Legs more extensively reddish orange than brown or black. S1-S6 reddish orange.

Pubescence. Face with tomentum densest on clypeus and around antennal socket, slightly sparser on upper paraocular area and vertexal area. Dorsum of mesosoma and metasoma with bands of off-white to pale yellow short appressed setae. Mesoscutum largely obscured by pale tomentum. Mesopleuron (excluding hypoepimeral area) entirely obscured by white tomentum. Metanotum with tomentum uninterrupted, uniformly off white. T1 with narrow and short discal patch largely obscured by pale tomentum. T2-T6 each with complete fascia, T2 with fascia with wide basomedially convergent anterolateral extensions of tomentum. S4 and S5 with long coppery to silvery subapical hairs, which individually are often darker apically.

Surface sculpture. Punctures dense. Labrum with larger and sparser punctures (i=1-2d) than clypeus (i<1d) (difficult to see in holotype because clypeus entirely obscured by tomentum; described from paratypes with hair removed). Small impunctate shiny spot lateral to lateral ocellus. Mesoscutum, mesoscutellum, and axilla coarsely and densely rugose-punctate. Tegula densely punctate mesally (i≤1d), less so laterally (i=1-2d). Mesopleuron with ventrolateral half densely punctate (i<1d) to rugose; mesopleuron with punctures more or less equally dense throughout (not visible in holotype because mesopleuron entirely obscured by tomentum; described from paratypes). Metasomal terga with punctures very fine, dense (i≈1d), evenly distributed on disc.

Structure. Preapical tooth obtuse. Labrum with pair of small subapical denticles not preceded by carinae (difficult to see in holotype; described from paratypes). Frontal keel not strongly raised. Scape with greatest length 2.0 × greatest width. F2 noticeably longer than wide (L/W ratio = 1.2). Preoccipital ridge not joining hypostomal carina, from which it is separated by about 1.5 MOD at its terminal. Mesoscutellum weakly 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 clearly visible, but unattached to mesoscutellum for less than 2/5 the medial length of axilla; axilla with lateral margin arcuate. Fore wing with three submarginal cells. Pygidial plate apically rounded, with large deep, well-separated punctures, with the interspaces shining.

FEMALE: Description as for male except for usual secondary sexual characters and as follows: F2 even longer than wide (L/W ratio = 1.5); mesopleuron densely hairy, except for two almost entirely bare patches (one beneath base of fore wing (hypoepimeral area), a larger circular patch occupying much of ventrolateral half of mesopleuron); T5 with large, continuous patch of pale tomentum bordering and contacting pseudopygidial area present only in female; T5 with pseudopygidial area lunate, its apex twice as wide as medial length, indicated by silvery setae on disc of apicomedial region elevated from rest of tergum; S4 and S5 with much shorter hairs (S5 with apical fimbria of coppery to silvery hairs not extending beyond apex of sternum by much more than 1/4 MOD); pygidial plate apically truncate, with small, denser punctures.

Etymology.

The name is in reference to the pale tomentum obscuring much of the integument of this species. From the Latin, “nebulosus” (hazy).

Distribution.

California and probably western Nevada (Fig. 72).

Ecology.

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

FLORAL RECORDS: Labels of examined voucher specimens indicate a floral association with Ericameria nauseosa .

Discussion.

Epeolus nebulosus is a cryptic species within the "pusillus group" that closely resembles some specimens of E. novomexicanus , and the ranges of the two species overlap to some extent. The morphological differences (in integument coloration and patterns of pubescence) among the four members of the "pusillus group" are subtle. The status of E. nebulosus as a separate species is further supported by a separate BIN and large barcode sequence divergence (>3.2%) from its nearest neighbor, E. novomexicanus . Although most species of Epeolus were described from a female name-bearing type, a male specimen is designated as the holotype of E. nebulosus because a barcode-compliant sequence is associated with it and because much of the pubescence is discolored or rubbed off in the available female specimen, which is herein designated as the allotype. Since this species is described from very few specimens, efforts should be made to collect additional representatives of E. nebulosus for DNA barcoding to determine if the morphological differences between it and E. novomexicanus reported here are consistent.

Material studied.

Type material. Primary: USA: California: Gilbert Pass on Hwy 168 (37.4305°N; 117.9388°W) (N Deep Springs Valley, Inyo County), 14.ix.2013, M.C. Orr (holotype ♂ [CCDB-28239 F01], BBSL).

Secondary: USA: California: 3.2 km S Pearblossom (Los Angeles County), 07.xi.1977, R.R. Snelling (allotype ♀, LACM); Gilbert Pass on Hwy 168 (37.4305°N; 117.9388°W) (N Deep Springs Valley, Inyo County), 14.ix.2013, M.C. Orr (paratypes 2♂, BBSL).

DNA barcoded material with BIN-compliant sequences.

Available. BOLD:ACZ0767. See Type material for specimens examined and sequenced (indicated by unique CCDB-plate and well number).