Epeolus nomadiformis, Onuferko, 2019

Onuferko, Thomas M., 2019, A review of the cleptoparasitic bee genus Epeolus Latreille, 1802 (Hymenoptera: Apidae) in the Caribbean, Central America and Mexico, European Journal of Taxonomy 563, pp. 1-69 : 38-41

Epeolus nomadiformis sp. nov.

urn:lsid:zoobank.org:act:905E8BD4-657C-4323-A2F4-A08B30F3484E

Figs 7H , 16

Proposed common name

Nomadiform epeolus.

Diagnosis

Together with the morphological features that are diagnostic for the ‘ Trophocleptria group’, the following in combination can be used to tell E. nomadiformis sp. nov. apart from all other Epeolus : the axillae are crenulate along the lateral margin, each with a large tooth near the base ( Fig. 16D ); the mesoscutellum has a pair of posteriorly directed teeth ( Fig. 16D ); the mesopleura are coarsely punctate, each with sparser punctures ventrolaterally (many i≥2d) than in the upper half, with interspaces smooth and shining; the fore wings are deeply infuscate apically ( Fig. 16 A–C); T1 has only a broad, medially narrowed or interrupted bright to pale yellow basal fascia ( Fig. 16 A–B); T2 has a complete bright to pale yellow apical fascia ( Fig. 16 A–B); and the remaining terga lack fasciae ( Fig. 16 A–C), although the apical impressed areas occasionally have sparse, off-white hairs. In overall appearance, this species is more nomadiform than epeoliform (sensu Michener 2007). Epeolus nomadiformis sp. nov. most closely resembles E. boliviensis and E. fulvopilosus , but in E. boliviensis T1 lacks a basal fascia, although a subapical fascia is present, which is usually narrower than the T2 apical fascia, and in E. fulvopilosus T3 and T4 are distinctly fasciate.

Etymology

The specific epithet is derived from ‘ Nomada ’, a genus of cleptoparasitic bees similar in overall appearance to this particular species of Epeolus . The Latin suffix – formis means ‘having the form of’.

Material examined

Primary type material

MEXICO • ♀, holotype; Veracruz, S Ixhuatlán (SE Huatusco); 17–18 Jul. 1990; I. Yarom leg.; KUNHM SEMC1248290 .

Secondary type material

BELIZE • 1 ♀, paratype; Stann Creek, Middlesex; 18 Mar. 1965; E.C. Welling leg.; CNC 754064 • 1 ♀, paratype; same collection data as for preceding; 7 Apr. 1965; E.C. Welling leg.; CNC 754063 .

MEXICO • 1 ♀, paratype; Nuevo León, Cola de Caballo ; 19 Jun. 1975; H.V. Weems Jr. leg.; FSCA • 1 ♀, paratype; Quintana Roo, 12 km NW of Reforma ; 14 Oct. 1986; C.D. Michener leg.; KUNHM SEMC1247933 • 1 ♀, paratype; Veracruz, El Desengaño ( El Mirador ); 19.2101° N, 96.8966° W; 26 Jul. 2006; M. Bonet leg.; BOLD sample ID: CCDB-28238 B01; BBSL 0000003960 • 1 ♀, paratype; Veracruz, Estación de Biología Los Tuxtlas (33 km NE of Catemaco); 1 Jul.–1 Aug. 1983; S. and J. Peck leg.; RAM .

DNA barcoded material with BIN-compliant sequences

Unavailable.

Description

Female

MEASUREMENTS. Length 8.5 mm; head length 2.1 mm; head width 2.5 mm; fore wing length 7.5 mm.

INTEGUMENT COLORATION. Mostly black; notable exceptions as follows: at least partially ferruginous on mandible, labrum, antenna, pronotal collar, pronotal lobe, tegula, axilla, mesoscutellum, metanotum, mesopleuron, propodeum, legs and pygidial plate. Mandible with apex darker than all but extreme base; preapical tooth lighter than mandibular apex. Antenna brown except scape, pedicel and F1 extensively orange. Pronotal collar, pronotal lobe and tegula pale ferruginous to amber. Wing membrane dusky subhyaline, slightly darker at apex. Legs with brown or black more extensive than reddish orange.

PUBESCENCE. Face with tomentum densest around antennal socket. Clypeus, upper paraocular and frontal areas, and vertexal area mostly exposed. Pronotal collar and dorsum of metasoma with bright to pale yellow short, appressed setae. Mesoscutum without pale tomentum, except for small patch between tegula and axilla. Mesopleuron nearly bare, except along margins. Metanotum with tomentum uninterrupted, uniformly pale yellow. T1 with broad, medially interrupted pale yellow basal fascia. T2 with complete bright yellow apical fascia, broadest medially and without anterolateral extensions. Metasoma otherwise without fasciae. T5 laterally with long, erect simple setae. T5 with pseudopygidial area lunate, its apex 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 ~½ MOD.

SURFACE SCULPTURE. Punctures dense, but those of head and mesosoma sparser in some areas, larger, deeper and more distinct. Labrum with areas of sparser punctures (i>1d) than clypeus (i<1d). Small impunctate matte spot lateral to lateral ocellus. Mesoscutum, mesoscutellum and axilla very coarsely and densely rugose-punctate. Tegula densely punctate anteriorly and mesally (i≤1d), sparsely punctate (i>2d) to impunctate posteriorly and along margins. Mesopleuron with denser (i<1d) punctures in upper half than ventrolateral half (i≤2d), interspaces shining though with some coriarious surface miscrosculpture; mesopleuron with punctures similar in size throughout. Metasomal terga with punctures very fine, dense (i≈1d), evenly distributed on disc.

STRUCTURE. Preapical tooth acute. Labral apex with pair of small denticles (separated by shallow concavity) not preceded by carinae. Frontal keel strongly raised. Frontal area with pair of discrete, sparsely punctate granulose protrusions, each located near upper mesal margin of compound eye. Head dorsally with pair of prominent protrusions, each located where upper genal area meets vertexal area. Vertexal area strongly convex in frontal view. Scape with greatest length 1.5 × greatest width. F2 noticeably longer than wide (L/W ratio = 1.4). Preoccipital ridge separated from hypostomal carina by no less than 1 MOD. Pronotal collar elongate (medial length ~1 MOD), expanded laterally to about 2 × medial length in dorsal view and relatively straight along anterior margin. Mesoscutellum weakly bigibbous, depressed along posterior margin beneath distinct overhanging ridge produced to pair of posteriorly directed teeth. Axilla large, its lateral margin more than half as long as mesoscutellar width (AL/MSCW ratio = 0.7) and tip extending as far back as apex of horizontal dorsal portion of mesoscutellum; 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 crenulate, with large tooth near base, and carinate but relatively straight. Mesopleuron with carina delineating its anterior and lateral surfaces. Fore wing with three submarginal cells. Pygidial plate apically truncate.

Male

Unknown.

Distribution

Central America and Mexico ( Fig. 7H ).

Ecology

Host records

Unknown.

Floral records

The label of one examined voucher specimen indicates a floral association with Bidens pilosa L. ( Asteraceae ).

Remarks

Females of Epeolus nomadiformis sp. nov. differ from those of E. fulvopilosus only in the absence of yellow tomentum along the midline of the mesoscutum and fasciae on T3 and T4. Otherwise, the two forms are virtually identical. The male of E. nomadiformis sp. nov. is presently unknown, and the only male of E. fulvopilosus was identified as such in part because it has pale yellow apical fasciae on T3 and T4 ( Fig. 10C ). Another species within the ‘ Trophocleptria group’, Epeolus obscuripes , exhibits continuous variation in the density of hairs on the apical impressed areas of T3 and T4; at one extreme the hairs are as dense as those on the preceding terga, whereas at the other they are virtually absent. Moreover, sequenced representatives of the two forms (with and without fasciae on T3 and T4) share the same BIN, further justifying their treatment as a single species. By contrast, in E. fumipennis , another species within the ‘ Trophocleptria group’, T3 and T4 (as well as T1 and T2) are always fasciate in both sexes.

Presently, no intermediates are known between E. fulvopilosus and the form that lacks fasciae on T3 and T4. DNA barcode sequences are presently not available for E. fulvopilosus , but a partial sequence 297 bp in length is available for a female specimen of what is herein considered to be E. nomadiformis sp. nov., from Veracruz (state), Mexico, which is most similar (99.7%) to the single BIN-compliant sequence available for E. claripennis (a visibly different bee, see Figs 8 , 16 ), obtained from a male specimen from San José Province, Costa Rica. Given the low level of genetic divergence between these two morphologically very different forms, it is unclear whether DNA barcodes would be helpful in differentiating E. nomadiformis sp. nov. from E. fulvopilosus , to which E. nomadiformis sp. nov. is even more similar. However, a lack of barcode sequence divergence would not necessarily mean that the different forms are conspecific anyway, as it is not uncommon in bees to have merged BINs with multiple species. For example, Gibbs (2017) found that 43 out of the 110 species of the Lasioglossum Curtis, 1833 subgenus Dialictus Robertson, 1902 ( Hymenoptera : Halictidae ) for which barcode data were examined were not assigned separate BINs, but all are considered valid and diagnosable using morphological features. Similarly, Packer & Ruz (2017) found no barcode sequence differentiation between two species of Chilicola Spinola, 1851 subgenus Chilioediscelis Toro & Moldenke, 1979 despite considerable morphological differences between them in both sexes and their not being sister taxa in a morphology-based phylogeny ( Willis & Packer 2007). Hence, in the absence of intermediates and since at this time there is no genetic evidence suggesting that the distinctly yellow-banded form, known as E. fulvopilosus , and that which consistently exhibits reduced mesosomal and metasomal pubescence are the same species, I have opted to treat them as heterospecific, and herein newly describe the latter under the name E. nomadiformis sp. nov.

Figures

Fig. 7 (opposite page). Occurrence records (yellow circles except where indicated otherwise) of: A. Epeolus boliviensis Friese, 1908. B. E. claripennis Friese, 1908. C. E. danieli (Genaro, 2014) comb. nov. (orange square) and E. luteipennis Friese, 1916. D. E. fulvopilosus Cameron, 1902. E. E. fumipennis Say, 1837. F. E. hanusiae sp. nov. G. E. niger (Michener, 1954). H. E. nomadiformis sp. nov. I. E. obscuripes Cockerell, 1917 stat. nov. J. E. odyneroides sp. nov. K. E. pulchellus Cresson, 1865.

Fig. 16. Epeolus nomadiformis sp. nov., ♀♀. A–B. Holotype, (KUNHM SEMC1248290). A. Habitus, lateral view. B. Habitus, dorsal view. C–D. Paratype, (CNC 754064). C. Habitus, lateral view. D. Axillae and mesoscutellum, dorsal view (blue arrow indicates one of two posteriorly directed tooth-like projections of mesoscutellum). Scale bars: A–C = 3 mm; D = 0.5 mm.

Fig. 10. Epeolus fulvopilosus Cameron, 1902. A. Female, habitus, lateral view. B. Female, habitus, dorsal view. C. Male, habitus, lateral view. D. Female axillae and mesoscutellum, dorsal view (blue arrow indicates one of two posteriorly directed tooth-like projections of mesoscutellum). Scale bars: A–C = 3 mm; D = 0.5 mm.

Fig. 8. Epeolus claripennis Friese, 1908. A. Female, habitus, lateral view. B. Female, habitus, dorsal view. C. Male, habitus, lateral view. D. Female axillae and mesoscutellum, dorsal view (blue arrow indicates one of two posteriorly directed tooth-like projections of mesoscutellum). Scale bars: A–C = 3 mm; D = 0.5 mm.