Scaptotrigona illescasi Engel, 2022

Engel, Michael S., 2022, Notes on South American stingless bees of the genus Scaptotrigona (Hymenoptera: Apidae), Part II: Subgroup A of the postica species group, Journal of Melittology 2022 (110), pp. 1-51 : 36-39

Scaptotrigona illescasi Engel , new species

ZooBank: urn:lsid:zoobank.org:act:5C5ED6EA-EAEF-4564-9D13-DCBF02803F4F

( Figs. 51–56 )

DIAGNOSIS: This western Ecuadorian species is comparatively dark, in this respect similar to S. ederi , but possessing a distinct genal tooth and yellow to dark fulvous bristles along the entire mesoscutal margin, although sometimes with a few black bristles intermixed. The tegular bristles are yellow, the mesepisternum is marked with areas of yellow to reddish orange, and the metabasitarsal bristles are predominantly black, including on the prolateral surface.

DESCRIPTION: As described for S. ederi (vide supra), with the following modifications: ⚲: Total body length approximately 5.8–6.0 mm, forewing length (to base of humeral sclerite) 5.8–5.9 mm. Head wider than long, width 2.36–2.42 mm, length 1.94–1.97 mm; compound eye length 1.39–1.42 mm; upper interorbital distance 1.52–1.55 mm, lower interorbital distance 1.42–1.45 mm. Scape length 0.91 mm, about as long as torulocellar distance, torulocellar distance 0.85–0.91 mm. Clypeus approximately 1.75–1.8× as wide as long, length 0.61 mm, width 1.06–1.09 mm. Malar area approximately 1.6× flagellar diameter or 0.73–0.75× basal mandibular width. Preoccipital ridge carinate, lamellate dorsally, with bordering medial and lateral indentations deep, carina interrupted laterally by deep concavity, lower margin of concavity with carina forming acutely rounded angle projecting upward as short, lamellate tooth; upper margin with lamella extended ventrally about half way into concavity.

Integument of labiomaxillary complex yellow orange; labrum orange; mandible reddish orange; clypeus largely yellow orange to orange with brown along apical margin and sometimes with brownish stain laterally and at apicolateral corners, epistomal sulcus well delineated by brownish orange to black; supraclypeal area orange with stain of brown at epistomal sulcus; malar space often orange to reddish orange; face below tangent of antennal toruli orange, albeit blending to more reddish orange toward antennal toruli, lower frons orange to reddish orange, sometimes largely brown to dark brown except around antennal toruli; scape orange to brownish orange, sometimes with brown dorsally; pedicel and flagellum brown to dark brown, flagellum orange underneath; vertex dark brown to black; posterior of head dark brown to black; upper third of gena dark brown to black, remainder of gena orange; postgena orange to yellow orange. Mesosoma black except pronotum orange to brown, mesoscutellum orange but sometimes with axilla black, mesepisternum reddish orange posteriorly but sometimes reddish orange anteriorly and orange posteriorly, sometimes propodeum orange with brown centrally on lateral surface; tegula yellow orange and semi-translucent; legs largely yellow orange to orange except dark brown on femora apically, on prolateral surfaces of pro- and mesotibiae, prolateral surface of pro- and mesobasitarsus, prolateral surface of metatibia except extreme base of fundus and sometimes superior distal angle, and prolateral surface of metabasitarsus except margins, sometimes dark brown areas reddish orange to reddish brown. Wing membranes lightly parchment colored; veins orange to orange brown. Metasoma generally dark brown to black except anterior-facing surface of tergum I orange to orange brown, dorsal-facing disc of tergum I posteriorly coppery orange, tergum II posteriorly coppery orange, with yellow marginal zone; terga III – IV with yellow apical marginal zones, typically obscured by tomentum; sterna dark brown basally and yellow to yellow brown apically in setal areas.

Areas of short, white, plumose setae in S. ederi instead yellow. Vertex with numerous erect, simple, yellow to dark fulvous bristles, sometimes with a few short black bristles laterally near upper orbit in darker forms; pronotal dorsolateral margin near and anterior to pronotal lobe with yellow to fulvous bristles; mesoscutum anterior and lateral borders with largely yellow to dark fulvous bristles sometimes intermixed with a few black bristles, typically anterolaterally; tegula with suberect yellow bristles anteriorly; mesoscutellum with abundant, elongate, erect yellow to fulvous bristles posteriorly; mesepisternum with scatered, erect to subdecumbent yellow fulvous bristles, longer ventrally, along rounded anterior border with preëpisternum a line of abundant, suberect to subdecumbent fulvous to dark fulvous bristles extending ventrally from pronotal lobe; lateral surface of propodeum with scatered, long, erect, yellow bristles emerging amid dense, appressed, yellow, plumose setae. Legs with abundant yellow to fulvous bristles except intermixed with dark fulvous to black bristles on protibia apically, prolateral surface of pro- and mesobasitarsi, and metafemur apically; metatibia with almost entirely black bristles; metabasitarsus with erect black bristles on margins intermixed with some yellow to fulvous bristles, prolateral surface with scatered fine, dark fulvous to black setae amid otherwise yellow to fulvous setae. Metasoma with numerous, prominent, suberect to subdecumbent, yellow bristles on terga III – V arising amid tomentum, such bristles sparser on tergum II.

♀: Latet.

♂: Latet.

HOLOTYPE: ⚲, Ecuador: Prov. San Mateo, Esmeraldas [Province Esmeraldas, San Mateo, approximately 2 miles south of the municipality of Esmeraldas], 9 October 1956, Foerster ( SEMC).

PARATYPES: 23⚲⚲, Ecuador: Prov. San Mateo, Esmeraldas [Province Esmeraldas, San Mateo, approximately 2 miles south of the municipality of Esmeraldas], 9 October 1956, Foerster ( SEMC); 13⚲⚲, Ecuador: Esmeraldas, San Mateo , 19 Sept 1956 ( SEMC) .

ETYMOLOGY: The specific epithet honors Alonso de Illescas (floruit 1528–circa 1596), leader of the African Maroons in the area of Esmeraldas, which encompasses the type locality.

Figures

Figures 51–52. Workers of Scaptotrigona illescasi, new species. 51. Lateral habitus, darker indi- vidual. 52. Lateral habitus, lighter individual.

Figures 53–56. Workers of Scaptotrigona illescasi, new species. 53. Facial view, darker individual. 54. Facial view, lighter individual. 55. Mesosomal dorsum, darker individual. 56. Mesosomal dorsum, lighter individual.