Scaptotrigona (Scaptotrigona) anaulax Engel, 2022

Engel, Michael S., 2022, Notes on South American stingless bees of the genus Scaptotrigona (Hymenoptera: Apidae), Part IV: Four new species of group B from the Andean region, Journal of Melittology 2022 (112), pp. 1-13 : 2-5

Scaptotrigona (Scaptotrigona) anaulax Engel , new species

ZooBank: urn:lsid:zoobank.org:act:4C142249-AC9F-4A20-9BFC-F446283B27E2

( Figs. 1–3 )

DIAGNOSIS: This is a dark species that can be easily confused with others in this group but is most easily distinguished by the lack of the deep concavity in the lateral part of the preoccipital carina, at most with a faint shallow depression. In this respect, the species resembles S. extranea Engel , which also lacks such a concavity and occurs in Pichincha, but in that species the overall coloration is lighter, typical of species in group A ( Engel, 2022b). More critically, the facial markings are wholly different ( Fig. 3 cf. Engel, 2022b: fig. 23) and S. extranea seems to be a relatively low-elevation species, occurring around 530 m, while S. anaulax is found from 1375–2600 m.

DESCRIPTION: ⚲: Total body length approximately 5.5–6.3 mm, forewing length (to base of humeral sclerite) 6.0– 6.3 mm. Head wider than long, width 2.50–2.53 mm, length 1.97–2.00 mm; compound eye length 1.33–1.43 mm; upper interorbital distance 1.63 mm, lower interorbital distance 1.50–1.53 mm. Scape length 0.93 mm, slightly longer than torulocellar distance, torulocellar distance 0.87–0.90 mm. Clypeus length 0.63–0.67 mm, width 1.17 mm. Malar area long, length 1.6–1.8× flagellar diameter. Preoccipital carina strong, bordered dorsally by deep medial indentation and briefly lamellate where bordering medial indentation, lateral indentations faint, laterally carina not interrupted by deep concavity, at most with a shallow depression.

Integument generally black to dark brown, with areas of dark brown sometimes nearly black; labiomaxillary complex brown; labrum brown; mandible brown to yellow brown; clypeus largely yellow to yellow brown, with areas of light brown to brown either apicolaterally or paramedially; supraclypeal area yellow to brown; malar space dark brown; face below tangent of antennal toruli largely semitranslucent or diaphanous yellow, with such yellow narrowly tapering upward along inner ocular margin for distance of about 1–2× antennal torular diameter; scape black to dark brown except yellow to yellow brown on ventral half to three-quarters; pedicel and flagellum dark brown; remainder of face dark brown to black; vertex and posterior of head black to dark brown; gena dark brown; postgena dark brown except hypostomal borders yellow. Mesosoma black; tegula dark brown to black; legs largely dark brown except sometimes brown on more proximal podites, tarsi brown to yellow brown, except metabasitarsus largely dark brown with posterior and sometimes anterior margins concolorous with remaining tarsomeres. Wing membranes hyaline and parchment-colored; veins largely yellow except yellow brown along anterior of wing. Metasoma dark brown to black except sometimes largely brown or even lighter brown on first two terga and basal sterna.

Integument smooth and shining amid punctures; clypeus and supraclypeal area with minute, shallow, widely scatered punctures; lower face with punctures as on clypeus albeit slightly larger and a bit more numerous, such punctures again minute on frons and separated by 2–4× a puncture width except denser just above antennal toruli and sparser as they blend into ocellocular area; punctures of vertex ill-defined amid irregular integument, blending to coarsely imbricate integument; posterior of head coarsely imbricate; gena with minute punctures separated by 1.5–3× a puncture width; postgena impunctate and finely imbricate. Mesoscutum and mesoscutellum with small contiguous punctures, integument between punctures, where evident, smooth; pleura with small contiguous punctures, punctures becoming somewhat weaker and a bit more spaced ventrally and posteroventrally; punctures of metepisternum smaller and more distinct than those of mesepisternum; propodeum with small contiguous punctures on lateral surface; basal area of propodeum tessellate to imbricate. Metasomal terga coarsely imbricate and minutely punctate, except anterior-facing surface of tergum I smooth, pregradular areas and exceptionally narrow apical marginal zones finely imbricate and impunctate; tergum VI more finely and faintly imbricate, particularly medially, and largely impunctate; sterna finely imbricate.

Fine pubescence generally consisting of minute to short, appressed or decumbent yellow or golden setae, such minute setae often simple but sometimes plumose, intermixed in places with fuscous to frequently black setae; minute golden setae sparse to absent on lower face, more numerous on frons except upper frons such setae blending to more fuscous setae and erect black setae and bristles; gena with scatered golden setae; postgena with elongate, erect, fuscous to nearly black setae. Pronotal lobe with dense, pale yellow, plumose setae; mesoscutum and mesoscutellum with scatered, minute, simple, subappressed to decumbent, fuscous setae, such setae more noticeable laterally, mesoscutum also with thin, plumose, pale yellow setae at anterolateral corners and somewhat along lateral margins; mesepisternum with short to long, erect to suberect, golden fuscous setae, intermixed with black bristles, with short, pale yellow, plumose setae on hypoepimeral area; metepisternum with dense, yellow, plumose setae; propodeum lateral surface with setae similar to that of metepisternum. Legs with largely black setae, except coxae, trochanters, and proximally on femora with long, yellow setae. Metasomal terga with minute, appressed to decumbent, simple, fuscous to golden fuscous setae, except anterior-facing surface of tergum I glabrous, tergum I with diffuse, thin, pale yellow, plumose setae apicolaterally (such setae often difficult to discern, best viewed in profile or obliquely), terga III–VI covered with dense, appressed to subappressed, yellow, plumose tomentum, and apically on tergum II (ranging from apical two thirds to simply near apical margin); sterna with elongate, erect, yellow to pale yellow simple scopal setae, such setae with wavy apices. Black bristles as follows: upper frons and vertex with black bristles, those of vertex longest; black bristles along anterior margin of pronotal lobe; mesoscutum anterior and lateral margins with abundant black bristles and some shorter bristles sparsely scatered on disc; tegula with suberect black bristles anteriorly; mesoscutellum with abundant black bristles, particularly along posterior margin, bristles longest along margin; black bristles scatered over mesepisternum and a distinct line of such bristles along round- ed margin with preëpisternum; lateral surface of propodeum with long, erect, fuscous to fulvous bristles arising amid tomentum; legs with numerous black bristles, those of distitarsomeres typically fulvous or intermixed black and dark fulvous; metatibial and metabasitarsal bristles black. Metasoma terga III–V with abundant, suberect to subdecumbent golden to fulvous bristles, sometimes a few fuscous, similar bristles longer and more erect on tergum VI, particularly along margin; terga I–II with such bristles short and present apicolaterally.

♀: Latet.

♂: Latet.

HOLOTYPE: ⚲, Ecuador: Pichincha, Mindo , 10.6 km W Mindo Road, 0°4’23’’S, 78°45’14’’W, 1375 m, 28 Mar 1999, D. Brzoska ( SEMC).

PARATYPES: 1⚲, Ecuador: Pichincha, Mindo , 10.6 km W Mindo Road, 0°4’23’’S, 78°45’14’’W, 1375 m, 28 Mar 1999, D. Brzoska ( SEMC) ; 35⚲⚲, Ecuador: Pichincha, Quito to Sto. Domingo , 2600 m, XII-20-1970 [20 December 1970], L. Peña ( AMNH) ; 2⚲⚲, Ecuador: Pichincha, Quito to Sto. Domingo , 2600 m, XII-20-1970 [20 December 1970], L. Peña ( SEMC) ; 3⚲⚲, Ecuador: Imbabura, Otavalo to Appuela , Sept. 8–10, 1977, 2200 m, L.E. Peña ( AMNH) ; 1⚲, Ecuador: Imbabura, Otavalo to Appuela , Sept. 8–10, 1977, 2200 m, L.E. Peña ( SEMC) .

ETYMOLOGY: The specific epithet is derived from the Ancient Greek noun αὖλᾰξ (aûlax, meaning, “furrow”), preceded by the alpha privative for negation (ᾰ – / a –). The name refers to the absence of the deep lateral interruption in the preoccipital carina that is otherwise so distinctive in most species of Scaptotrigona .

Figures

Figures 1–3. Workers of Scaptotrigona (Scaptotrigona) anaulax, new species. 1. Lateral habitus. 2. Dorsal habitus. 3. Facial view.