Lestrimelitta diminuta, Guevara & Gonzalez & Ospina, 2020

Guevara, Diego A., Gonzalez, Victor H. & Ospina, Rodulfo, 2020, Stingless robber bees of the genus Lestrimelitta in Colombia (Hymenoptera: Apidae: Meliponini), Caldasia 42 (1), pp. 17-29 : 19-21

Lestrimelitta diminuta , new species

ZooBank LSID: urn:lsid:zoobank.org:act:472FC958-6FCE-41BB-8CEA-833D91D3E8CA

Holotype. COLOMBIA. Guainía: ♀, San Felipe , 8 m [m.a.s.l.], 15-V-2014 [15 May 2014], Col: J. M. Rosso / 31086 ( LABUN).

Paratypes. 2♀, same data as holotype but with catalogue numbers 31087 ( SEMC) and 31088 ( LABUN) .

Diagnosis: This species resembles L. nana Melo, 2003 in the small body size (head width, ~ 1.6 mm), pro- and mesotibiae without erect setae on outer surfaces, mesoscutellum flattened and not covering metanotum medially, and mesotibial spur normal ( Fig. 1 ). It can be separated from that species by the following combination of features: propodeal spiracle elongate (5.9× longer than wide), pronotal lobe and mesoscutum with erect setae, mesepisternum with decumbent setae, terga with erect or semi-erect setae at least laterally, and mandible with a single tooth on apical margin. In L. nana , the propodeal spiracle is much broader, 3.0× longer than wide, the mesoscutum, mesepisternum, and terga are glabrous (except on T6), and the mandible is bidentate. Lestrimelitta diminuta shares with L. monodonta Camargo and Moure, 1989 the mandible with a single apical tooth, the propodeal spiracle elongate, and vertex, mesoscutum, mesepisternum, and terga with setae. However, L. monodonta is larger (head width: 2.2 mm vs. 1.6 mm), the setae on mesepisternum are long and erect (short and decumbent in L. diminuta ), the mesotibial spur is reduced (long in L. diminuta , 1.2× mesobasitarsal width basally), and the mesoscutellum is elevated, not flattened and partially covering metanotum medially (mesoscutellum flattened, not covering metanotum medially in L. diminuta ).

Description. ♀. Total body length 4.8 mm; forewing length 3.4 mm; head width 1.6 mm; maximum width of T2 1.3mm. Head 1.3× broader than long; inner orbits of compound eyes subparallel; malar area0.9× median ocellar diameter; clypeus 2.8× broader than long; intertorular distance shorter (0.9×) than torular diameter; torulorbital distance 1.5× torular diameter, 1.7× intertorular distance; interocellar distance 2.3× median ocellar diameter, shorter (0.7×) than ocellocular distance; scape about 5.7× longer than wide; pedicel longer than broad (1.5×); first flagellomere about as long as broad (1.1×), longer than second flagellomere (1.9×), remaining flagellomeres broader than long, except apical flagellomere much longer than broad; compound eye 2.4× longer than broad; gena broader than width of compound eye in profile (1.3×); mandible with a single tooth on apical margin. Mesoscutellum flattened, not covering metanotum medially; propodeal spiracle

Guevara et al. 2020, Caldasia 42(1):17-29

elongate, about 5.9× longer than wide; mesotibial spur long, about 1.2× mesobasitarsal width basally; metatibia about 3.0× longer than broad.

Integument smooth and shiny between minute, sparse punctures as in other species of the genus; sterna weakly lineolate-imbricate.

Color predominantly dark reddish-brown, lighter on labrum, mandible (except basally), clypeal margin, pro-, meso-legs, and sterna. Wing membrane hyaline; veins and pterostigma brown.

Body largely glabrous, sparsely covered with minute, appressed, simple, yellowish setae on head and mesosoma, setae longer and denser on mesoscutum, mesepisternum, and metepisternum. Propodeum laterally with short, appressed, minutely branched, whitish setae (integument largely visible among setae). Erect, long, stout, dark brown setae on: distal margin of labrum and inferior margin of mandible (longest, ≥ 2.0× OD); vertex and preoccipital border with few, sparse setae (at most half width of OD); anterior (2.0× OD) and lateral margins (next to axilla) of mesoscutum (1–1.2× OD); axilla (~OD); pronotal lobe (~OD); mesoscutellum with sparse setae on disc (~OD), much longer (2.0× OD) on distal margin; meso- and metacoxae, mesotibia, and propodeum (1–1.5× OD); posterior margin of metatibia (0.9–1.5× OD), side of T1 (0.5× OD), sides of T2–T4, entire T5 and T6 (0.6–2.0× OD).

Etimology. The specific epithet, diminuta , refers to the small body size of this species.

Comments. This species is known from the type locality in the Colombian Amazon ( Fig. 2 ). Marchi and Melo (2006) indicated that some specimens of L. monodonta from Pará (Tucuruí and Jacareacanga) and Maranhão (Urbano Santos), Brazil, are smaller than are specimens from other localities. These authors did not mention the size of these specimens, but they might be confused with L. diminuta . However, Marchi and Melo (2006) were not able to find significant differences in other features besides body size with the typical specimens of L. monodonta . Thus, small specimens of L. monodonta can be separated from L. diminuta by the same features indicated in the key to species.

Figures

Figure 1. Female holotype of Lestrimelitta diminuta Guevara, Gonzalez and Ospina, new species. a. facial habitus; b. lateral habitus; c. dorsal habitus; d. metasoma in dorsal view; e. propodeal spiracle. Scale bar: 0.5 mm except 0.25 mm in figure e.

Figure 2. Collection localities for the stingless bee genus Lestrimelitta in Colombia.