Nannotrigona melanocera ( Schwarz, 1938 )

Rasmussen, Claus & Gonzalez, Victor H., 2017, The neotropical stingless bee genus Nannotrigona Cockerell (Hymenoptera: Apidae: Meliponini): An illustrated key, notes on the types, and designation of lectotypes, Zootaxa 4299 (2), pp. 191-220 : 203

Nannotrigona melanocera ( Schwarz, 1938)

Figures 1 A–F, 3B, 5B, 6D, 7D, 9C,D, 11D

Trigona (Nannotrigona) testaceicornis melanocera Schwarz, 1938: 485 [holotype: USNM 53067 ; worker, Santa Helena, Bolivia]

Diagnosis. This species can be recognized by the combination of the following features: mesoscutum and mesoscutellum densely and coarsely foveate; antennal scape with long erect setae, at least 1.7 times longer than diameter of scape; and mesoscutellum with median emargination shallow, about 3.3 times broader than long. It is most similar to N. chapadana , from which it can be separated by the longer setae on the antennal scape and the dark brown flagellum.

Redescription. Holotype worker: Total body length 4.35 mm; head width 1.79 mm; maximum width of mesoscutum 1.41 mm; forewing length (including tegula) 4.5 mm. Head 1.1 times wider than long; malar area about 0.6 times width of F3; clypeus about 1.4 times broader than long; intertorular distance 1.7 times torular diameter; torulorbital distance 2.1 times torular diameter; interocellar distance 2.3 times OD, 1.1 times longer than ocellocular distance; ocelloccipital distance 2.1 long as OD; scape 4.9 times longer than wide, 0.9 times width of F3; flagellomeres broader than long, except apical flagellomere longer than broad. Mesoscutellum 1.5 times broader than long, basal fovea V-shaped, longer than broad, posterior margin with median emargination about 3.3 times broader than long, tooth lateral to emargination acute. Measurements of other structures in Table 3.

Color black, except as follows: light brown on apical two-thirds of mandible; brown on antennal scape and flagellum; bright pale yellow on lateral margin of mesoscutum, axilla, lateral tooth of posterior margin of mesoscutellum, outer surfaces of pro- and mesotibiae basally, posterior margin of metatibia, except apical half; brown on distitarsi, and anterior and posterior margins of metabasitarsus. Wing membrane, veins and pterostigma dark brown.

Pubescence pale, except basitarsus golden brown. Antennal scape with simple, long (2× diameter of scape) setae along its inner margin.

Clypeus and supraclypeal area with minute, shallow punctures; frons with contigous, coarse punctures as on ocellocular area. Mesoscutum and mesoscutellum densely and coarsely foveate.

Provenance. Numerous specimens from Venezuela, Peru and Bolivia were included in the type series by Schwarz, but the holotype was collected in Bolivia by the later director of the National Zoo in Washington, D.C., William M. Mann (1886–1960). The collection of the holotype was made between 23 August and 31 August, 1921, when the Mulford Biological Exploration expedition camped near Huachi [ San Miguel de Huachi ] on Río Bopi , before the junction forming Río Alto Beni. From their camp site Mann made excursions including up the Río Santa Elena to “ Santa Helena a locality visited rarely by Indians on hunting trips” [upstream from 15.936° S, 66.869° W, in the Cochabamba Department] ( Mann, 1925; Snyder, 1926). The collecting trip of this expedition was described in the 1926 witty and sarcastic book “White Waters and Black” by anthopologist Gordon MacCreagh and might have served as the real life inspiration for the movie character “Indiana Jones”.

Type material examined. 1 holotype worker from Bolivia, “ Aug ”, “ StaHelena / Bolivia / WmMMann”, “ Mulford / BioExpl / 1921-22 ”, “ HOLOTYPE ” (red label), “ Type No. / 53067 / U.S.N.M.”, “ Trigona / ( Nannotrigona ) / testaceicornis / melanocera / H.F.Schwarz ”, “ USNM ENT / 00534510” (yellow barcode label) ( USNM). Additional paratypes in AMNH and CUIC not examined.

Distribution. Bolivia (El Beni, La Paz, Santa Cruz); Brazil (Acre, Amazonas, Rondônia); Ecuador (Morona- Santiago, Napo, Sucumbíos); Peru (Junín, Madre de Dios, Pasco, San Martín); Venezuela (Aragua, Miranda).

Figures

FIGURE 1. Nest of Nannotrigona melanocera (Tarapoto, Peru): A. Colony adapted to a polystyrene nesting box. Often, colonies of this species fill the empty parts of the box with abundant short pillars and connectives, thus omitting the batumenlike lining surrounding the brood combs. B. A worker bee finishing construction of a brood cell. C. The top of the spiral formed brood comb. D. A regular entrance, about five years old, which has been expanded and leaving the newest and apical wax lighter. E. Unlike most stingless bee genera, workers of Nannotrigona seal with wax the nest entrance at sunset. In this picture the entrance is partly closed. F. Completely closed nest entrance.