Scaptotrigona (Gymnotrigona) psile, Engel, 2022

Engel, Michael S., 2022, Notes on South American stingless bees of the genus Scaptotrigona (Hymenoptera: Apidae), Part III: A revised infrageneric classification and new species, Journal of Melittology 2022 (111), pp. 1-29 : 17-20

Scaptotrigona (Gymnotrigona) psile Engel, new species

ZooBank: urn:lsid:zoobank.org:act:3CCE4850-7696-4350-9EC2-B4FCF68C3367

( Figs. 30, 31 )

DIAGNOSIS: This species is superficially similar to S. aurantipes but differs in the absence of extensive orange markings and presence of black bristles on the vertex and mesoscutum. From other species with minute tergal fimbriae and dark body coloration, S. psile can be distinguished by the absence of a genal tooth and the complete absence of lateral bristles on metasomal terga II and III.

DESCRIPTION: As described for S. totobi (vide supra) except as follows: ⚲: Total body length approximately 5.4–5.9, forewing length (to base of humeral sclerite) 5.5–5.8 mm. Head wider than long, width 2.42–2.45 mm, length 2.00– 2.03 mm; compound eye length 1.39–1.42 mm; upper interorbital distance 1.58–1.61 mm, lower interorbital distance 1.45–1.48 mm. Scape length 0.91 mm, slightly longer than torulocellar distance, torulocellar distance 0.85–0.88 mm. Clypeus approximately 1.6–1.7× as wide as long, length 0.58–0.64 mm, width 1.03 mm. Malar area long, length approximately 1.6× flagellar diameter. Preoccipital carina strong, lamellate dorsally and bordered by deep medial and lateral indentations, carina interrupted laterally by deep concavity, preoccipital lamella not extending into concavity, lower margin of concavity rounded, not projecting upward as tooth.

Integument generally black to dark brown; clypeus and supraclypeal area chestnut brown; face below tangent of antennal toruli chestnut brown along inner orbit, blending to faint yellow or yellow brown by clypeus and lower antennal torulus; malar space chestnut brown; scape dark brown above, light brown to yellow brown ventrally; flagellum dark brown except light brown to orange below; hypostomal borders yellow brown.

Integument smooth and shining amid punctures; clypeus with small shallow punctures separated by a puncture width or less; supraclypeal area as on clypeus; lower face with small shallow punctures as on clypeus along inner orbit blending to sparse toward epistomal sulcus and antennal torulus; such punctures becoming more well defined and separated by a puncture width or less on frons and ocellocular area; punctures of vertex ill-defined and blending to coarsely imbricate integument; posterior of head coarsely imbricate; gena with punctures similar to frons; postgena nearly impunctate. Mesoscutum and mesoscutellum with small contiguous punctures, integument between punctures, where evident, smooth; pleura with small contiguous punctures, punctures slightly weaker ventrally; punctures of metepisternum smaller and more distinct than those of mesepisternum; propodeum with small contiguous punctures on lateral surface; basal area of propodeum tessellate. Metasomal terga coarsely imbricate, except anterior-facing surface of tergum I smooth, apical marginal zones virtually absent; tergum V a bit less coarsely imbricate; tergum VI finely imbricate and largely impunctate; sterna finely imbricate.

Fine pubescence generally consisting of sparse, minute, appressed or decumbent white to fulvous setae, such minute setae often simple but sometimes plumose, intermixed in places with black setae; minute fulvous setae sparse on lower face, more numerous on frons except upper frons such setae blending to more erect largely simple, fulvous setae and black bristles; gena with scatered fulvous setae similar to that of face; postgena with erect, light fulvous setae. Pronotal lobe with dense, white to fulvous, plumose setae; mesoscutum and mesoscutellum with scatered, minute, simple, subappressed to decumbent, fulvous setae; metanotum with abundant, white, plumose setae; mesepisternum with similar setae to that of mesoscutum, such setae blending ventrally to longer, more white or light fulvous setae ventrally; metepisternum with dense, white, plumose setae; propodeum lateral surface with similar setae to that of metepisternum. Legs with largely fulvous setae. Metasomal terga with minute, appressed fulvous setae sparse, such setae more abundant and noticeable on terga IV–VI, and longer on terga V and VI, except anterior-facing surface of tergum I glabrous; terga II–V with apical fimbriae of minute, fine, simple, fulvous setae; sterna with elongate, erect, simple, light fulvous scopal setae, such setae with wavy apices. Bristles in distinct areas of body: Labrum with some erect, simple bristles; upper frons and vertex with black bristles, those of vertex longest, particularly medially posterior to ocelli; fulvous to black bristles along anterior margin of pronotal lobe; mesoscutum anterior and lateral margins with abundant black bristles; tegula with suberect black bristles anteriorly, sometimes with a few fulvous bristles intermingled; mesoscutellum with fulvous to black bristles, particularly long and abundant along posterior margin; fulvous bristles scatered over mesepisternum and a distinct line of fulvous and black bristles along rounded margin with preëpisternum; legs with numerous black bristles, those of distitarsomeres typically fulvous; metatibial and metabasitarsal bristles black and frequently with fulvous tips. Metasoma terga I–V without bristles on discs; terga I–III without bristles laterally, except sometimes with one or two short, subdecumbent, fulvous bristles at apicolateral margin on tergum III; terga IV and V with short, subdecumbent, fulvous bristles laterally; tergum VI with such bristles sparse on disc, and long, erect, fulvous bristles laterally and along margin.

♀: Latet.

♂: Latet.

HOLOTYPE: ⚲, Venezuela: Monagas, La Pica (5 km E), 9°50’N, 63°3’W, 6 November 1980, G.W. Otis ( SEMC).

PARATYPES: 8⚲⚲, Venezuela: Monagas, La Pica (5 km E), 9°50’N, 63°3’W, 6 November 1980, G.W. Otis ( SEMC) .

ADDITIONAL MATERIAL: 1⚲, Venezuela: Fed. Dist., Caracas Bot. Garden, Santa Rosalia Park, 19 Jan. 1980, N. Ramirez, ex flowers Luehea [ Malvaceae : Grewioideae: Luehea Willd. ] (SEMC).

ETYMOLOGY: The specific epithet is taken from the Ancient Greek adjective ψῑλός (psīlós, feminine ψῑλή / psīlḗ), meaning, “bare”.

Figures

Figures 30–32. Workers of Scaptotrigona Moure. 23. Lateral habitus of Scaptotrigona (Gymnotrigona) psile, new species. 31. Facial view of S. (G.) psile. 32. Facial view of S. (G.) guimaraesensis Laroca & Almeida.