Nannotrigona mellaria ( Smith, 1862 )

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 : 203-206

Nannotrigona mellaria ( Smith, 1862)

Figures 2 E, 3A, 5C, 6E, 7E, 9E,F, 11E

Trigona mellarius Smith, 1862: 42 [lectotype: BMNH; worker, Panama] new lectotype designation

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, about 1.5 times longer than the diameter of scape ( Fig. 2 E); and mesoscutellum with median emargination deep, semicircular, about 2.6 times broader than long ( Fig. 3 A, 6E). It resembles N. melanocera in the scape with long setae, but can be separated by the mesoscutellum with a distinctly deep median emargination on the distal margin (shallow, V-shaped in N. melanocera , Fig. 3 B). From N. tristella , it can be distinguished by the features indicated in the key.

Redescription. Lectotype worker: Head width 2.01 mm; maximum width of mesoscutum 1.62 mm; forewing length (including tegula) 5.1 mm. Head 1.1 times wider than long; malar area about 0.6 times width of F3; clypeus about 1.9 times broader than long; intertorular distance 1.3 times torular diameter; torulorbital distance 1.5 times torular diameter; interocellar distance 2.3 times OD, 1.3 times longer than ocellocular distance; ocelloccipital distance 1.8 long as OD; scape 5.5 times longer than wide, 1.2 times width of F3; flagellomeres broader than long, except apical flagellomere longer than broad. Mesoscutellum 1.6 times broader than long, basal fovea broadly Vshaped, almost as broad as long, posterior margin with median emargination large, semicircular, about 2.6 times broader than long, tooth lateral to emargination acute. Measurements of other structures in Table 3.

Color black, except as follows: reddish brown on apical two-thirds of mandible, antennal scape, flagellum; 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; dark brown on distitarsi, and anterior and posterior margins of metabasitarsus. Wing membrane, veins and pterostigma dark brown.

Pubescence yellowish white, except basitarsus golden brown. Antennal scape with simple, long (1.5× diameter of scape) setae along its inner margin.

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

Provenance. The type specimens were collected by Richard Harper Stretch (1837–1926) in Panamá and presented as a gift in 1860–1861 to the private collection of Frederick Smith (1805–1879). Years after the passing of Smith, in 1899, the bulk of Smith’s private collection was donated back to the BMNH as part of 17451 specimens, mostly aculeate Hymenoptera from the collection of the late Reverend William Farren White (1834– 1899), courtesy of Mrs . Farren White of Stonehouse, 16 Churchfield Road, London Borough of Ealing. The collector Stretch was cited as R. “W.” Stretch by Smith (1862), an interpretation error originating from the handwritten correspondence, as Richard Harper Stretch was the Englishman who went to the Americas to collect insects on 14 January, 1860 ( Craigan , 2008). Stretch visited Halifax ( Canada), Boston , New York (USA) and arrived in Aspinwall (now Colón), Panama on 14 February, 1860. Stretch left the country again after a month of intensive travel and collecting on 18 March, 1860. In the diary of Stretch ( Craigan , 2008) is listed a specific collecting event with the accession number “10”, identical to the number on the syntype specimens of N. mellaria . All three syntypes are labeled with a blue label and hand-written in ink is the number “10”. Stretch wrote under this accession number in his diary “10 / Hymenoptera, Lion Hill. Nest in Hollow Tree / 8 / 9 / 3 / 6o.”. The type locality for accession 10 is the abandoned Lion Hill railroad station, or railroad camp, in the Chagres Valley [app. 9.28° N, 79.74° W]. The remaining information refer to the identification [ Hymenoptera ], the quantity [8 specimens], and the date of the collection [9 March, 1860]. The diary entry for this day even details the collection of N. mellaria , which reads: “Went over to Panama [from Colón] and I spent the afternoon collecting. At Malachin purchased from a native a small rodent resembling a peccary, intending to send it to England. About 2 miles from Gatun the conductor very obligingly stopped the train for me to procure specimens of a bee whose nest occupied the interior of an immense tree, recently cut down by the tracks” ( Craigan, 2008). Stretch was an eminent naturalist, very interested in entomology, and no doubt exists that Smith received the bees from Richard Harper Stretch and not some R. “W.” Stretch. Smith himself wrote upon describing the new species that the collection from Stretch was accompanied by a “several valuable notes on the economy of some of the species”, which for this particular species included the following: “A very large tree having fallen, it was cut in two to remove it; the inside was found to be quite hollow for many feet; the space left empty was completely lined with the nest of this small bee” ( Smith, 1862). It is noteworthy that N. mellaria always nest together with aggressive ants ( Roubik, 1983), which should have been present in trunk or somehow escaped the attention of R. H. Stretch. The ants could also have abandoned the tree after it was felled, but before it was cut open.

Type material examined. 1 lectotype (here designated) worker from Panamá, “10” (blue label), “ Smith coll. / pres. by / Mrs. Farren White. / 99-303”, “ Panama ”, “ Trigona (Nannotr.) / testaceicornis / mellaria (Smith) / Det. Schwarz” ( BMNH) ; 1 paralectotype workers, “ Type ” (orange circle, circular label), “ B.M. TYPE / HYM. / 17B.1089.”, “ Trigona mellarius ”, “10” (blue label), “ Smith coll. / pres. by / Mrs. Farren White. / 99-303” ( BMNH) ; 1 paralectotype worker, “10” (blue label), “ Smith coll. / pres. by / Mrs. Farren White. / 99-303”, “ Panama ”, “ Trigona (Nannotr.) / testaceicornis / mellaria (Smith) / Det. Schwarz” ( BMNH); 1 possible paralectotype worker, “ Smith coll. / pres. by / Mrs. Farren White. / 99-303”, “ Trigona (Nannotr.) / testaceicornis / mellarius (Sm.) / Det. Schwarz ” ( BMNH).

We here interpret three specimens from the BMNH labeled with the hand-written number “10” as equally valid syntypes. Unfortunately, all three specimens are damaged to some degree. A specimen labeled “Type” is missing the head and the thorax is crushed and damaged. A second specimen is missing the head whereas the third and last specimen is the only specimen with the head preserved. However, the right antenna, abdomen, and both hind legs are missing. Although a single specimen was separated earlier from the general collection of BMNH and is labeled (not by Smith) as the “type” (specimen BMNH 17B.1089), the account by Smith clearly indicates that the species was described from a nest, and all specimens with identical labels of providence, originating from the personal collection of Smith, can be considered syntypes. The specimens labeled as the “type” is headless and represent the most damaged specimen. Thus, it would not be desirable to select this particular specimen as the lectotype. Instead, we here designate the only syntype specimen with intact head as the lectotype in order to stabilize the future use of the name. The specimen has been labeled accordingly and the remaining two syntypes in BMNH are labeled paralectotypes.

Distribution. Colombia (Cundinamarca, Huila, Valle del Cauca); Costa Rica (Heredia, Puntarenas); Ecuador (Guayas); Nicaragua (Río San Juan); Panama (Chiriquí, Darién, Panamá); Peru (Piura).

Figures

FIGURE 2. Key couplet features of Nannotrigona species: A. N. schultzei (KU 1381942, Bolivia, El Beni), sparsely punctate mesoscutum. B. N. perilampoides (KU 1382363, Mexico, Oaxaca), mesoscutum densely and coarsely foveate. C. N. dutrae (Paralectotype), strongly carinate omaulus. D. N. perilampoides (KU 1382363, Mex, Oaxaca), setae on scape shorter than scape diameter. E. N. mellaria, setae on scape about as long as scape diameter.

FIGURE 3. Key couplet features of Nannotrigona species: A. N. mellaria, posterior margin of mesoscutellum with deep and semicircular emargination. B. N. melanocera (KU 1381940, Bolivia, El Beni), posterior margin of mesoscutellum with shallower emargination. C. N. perilampoides (KU 1382363, Mexico, Oaxaca), ocellocular area, between the lateral ocellus and the eye, with punctures almost similar to those on the frons. D. N. testaceicornis (KU 1381957, Brazil, São Paulo), ocellocular area, between the lateral ocellus and the eye, with scattered and larger punctures separated by glabrous interspaces. E. N. testaceicornis (KU 1381957, Brazil, São Paulo), clypeus duller, with minute, coarse punctures. F. N. punctata (KU 1382096, French Guiana, Kourou), clypeus shiny, with minute shallow punctures.