Scaptotrigona extranea 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 : 17-20

Scaptotrigona extranea Engel , new species

ZooBank: urn:lsid:zoobank.org:act:29C44161-56F9-4AE4-8326-D8A51217F494

( Figs. 21–25 )

DIAGNOSIS: This is a rather unique species in that the concavity that typically interrupts the preoccipital carina laterally is exceptionally shallow and faint and does not disrupt the carina ( Fig. 25 ). In addition, the preoccipital ridge is faintly lamellate dorsally and the bordering medial and lateral indentations are weak and shallow ( Fig. 25 ). It is similar in several respects to S. kuperi , but can also be distinguished by the facial coloration in which the frons is largely dark brown to black, with yellow to yellow orange extending upward along the inner orbits ( Fig. 23 ), while in the former the entire lower part of the frons orange ( Fig. 20 ). In addition, the back of the head is entirely dark brown to black in S. kuperi , versus orange and marked with dark brown stripes in S. extranea ( Figs. 22 , 24, 25 ).

DESCRIPTION: As described for S. ederi (vide supra), with the following modifications: ⚲: Total body length approximately 6.3 mm, forewing length (to base of humeral sclerite) 5.8 mm. Head wider than long, width 2.30 mm, length 1.91 mm; compound eye length 1.33 mm; upper interorbital distance 1.48 mm, lower interorbital distance 1.42 mm. Scape length 0.88 mm, as long as torulocellar distance, torulocellar distance 0.88 mm. Clypeus approximately 1.7× as wide as long, length 0.58 mm, width 1.00 mm. Malar area approximately 1.6× flagellar diameter or 0.73× basal mandibular width. Preoccipital ridge carinate, faintly lamellate dorsally, with bordering medial and lateral indentations weak and shallow, carina not interrupted laterally, merely a faint concavity not interrupting carina.

Punctures of face fainter and sparser than in S. ederi .

Integument of labiomaxillary complex yellow orange; labrum yellow orange; mandible orange; clypeus yellow orange stained with areas of brown laterally and mediobasally, apical margin stained with brown, epistomal sulcus well delineated by dark brown to black; supraclypeal area yellow orange; malar space orange; face below lower tangent of antennal toruli yellow, with narrow yellow strip extending upward along inner orbit, frons and vertex dark brown to black albeit dark reddish brown above antennal toruli, separated from upper orbit by strip of orange to reddish brown, yellow orange mark anterior to median ocellus, most of ocellocular area orange; posterior of head largely orange except with oblique lateral strips of reddish brown extending from ocellocular area to preoccipital carina, preoccipital carina black; gena and postgena orange to yellow orange; scape orange; pedicel and flagellum brown, with flagellum orange ventrally. Mesosoma largely orange except mesoscutum black, mesoscutellum largely black except dark fulvous to ferrugineous apically, metanotum black, basal area and posterior surface of propodeum black; mesepisternum with dark brown ventrally and metepisternum dark brown long borders; tegula wholly yellow orange and semi-translucent; legs orange. Metasoma generally dark brown to black except anterior-facing surface of tergum I reddish brown, dorsal-facing disc of tergum I dark orange to brown apically; tergum II with broad apical zone of brown; sterna dark reddish brown to dark brown.

As for S. ederi except areas of short, plumose setae yellow to pale yellow instead of white; metepisternum and lateral surface of propodeum obscured by dense, plumose, yellow setae; dorsal-facing surface of tergum I densely covered with minute, decumbent, yellow, plumose setae similar to tomentum of apical margin of tergum II and discs of terga III – IV. Bristles of vertex erect, simple, yellow to fulvous; pronotal dorsolateral margin near and anterior to pronotal lobe with long, arched, yellow bristles; mesoscutum anterior and lateral borders with erect bristles, those on lateral border short, anterior margin with mix of yellow and dark fulvous to black bristles, such bristles intermixed along entire margin; tegula with short, suberect, yellow bristles anteriorly; mesoscutellum with abundant, elongate, erect bristles posteriorly, such bristles minutely pectinate apically, discal bristles shorter, mesoscutellar bristles largely yellow except medioapically more fulvous to fuscous; mesepisternal bristles as in S. ederi except yellow. Legs with abundant bristles, bristles typically yellow to orange except noticeably intermixed with fuscous to black bristles margin of protibia, prolateral surface of probasitarsus, prolateral and marginal surface of mesotibia, prolateral surface of mesobasitarsus, metafemur apically, metatibia, and a few metabasitarsus marginal bristles; corbicular bristles black, contrasting fulvous marginal bristles, some of later with fuscous bases; prolateral surface of metabasitarsus with scatered fine, simple, yellow to fulvous setae (noticeably thinner than marginal bristles), without black setae; penicillum black; rastellum yellow. Metasoma with numerous, prominent, suberect to subdecumbent, yellow bristles on terga III – V arising from tomentum.

♀: Latet.

♂: Latet.

HOLOTYPE: ⚲, Ecuador: Pichincha, Pedro Vicente Maldonado , 3.5 km N, 530 m, 0°6’44’’N, 79°3’21’’W, 29 Mar 1999, R. Brooks ( SEMC).

ETYMOLOGY: The specific epithet is the Latin adjective extrāneus, meaning, “strange”, and refers to the near absence of a concavity in the lateral portion of the preoccipital ridge.

Figures

Figures 21–23. Worker of Scaptotrigona extranea, new species. 21. Lateral habitus. 22. Dorsal habitus. 23. Facial view.

Figures 24–25. Worker of Scaptotrigona extranea, new species. 24. Dorsal view, head and meso- soma. 25. Dorsal oblique view of vertex and upper gena.

Figures 18–20. Worker of Scaptotrigona kuperi, new species. 18. Lateral habitus. 19. Dorsal habi- tus. 20. Facial view.