Proplebeia vetusta, CAMARGO & GRIMALDI & PEDRO, 2000

CAMARGO, JOÃO M. F., GRIMALDI, DAVID, A. & PEDRO, SILVIA R. M., 2000, The Extinct Fauna of Stingless Bees (Hymenoptera: Apidae: Meliponini) in Dominican Amber: Two New Species and Redescription of the Male of Proplebeia dominicana (Wille and Chandler), American Museum Novitates 3293, pp. 1-1 : 1-

Proplebeia vetusta , new species

Figures 8 , 11–14 , 22

Plebeia sp. ; Poinar, 1994 b: 73, fig 2 (fossil review).

DIAGNOSIS: Worker. Differs from P. dominicana by the large body size (3.80–4.40 mm; P. dominicana , 3.0 mm), forewing length (2.88–3.16; P. dominicana , 2.50–2.75 mm); malar area a little longer than diameter of scape; clypeus yellowish on distal third; parocular areas with a yellow stripe, slightly truncate above the tentorial pits (in holotype); and mandible with only a slight emargination separating the two denticles (in P. dominicana the emargination between denticles is deep).

DESCRIPTION: Worker (AMNH­DR­14­ 1481). Dimensions: Approximate body length 3.80 mm (metasoma quite compressed; in paratypes AMNH­DR­14­854 and DR­14­1440 approximate body length 4.40 and 4.32 mm, respectively); forewing length 2.88 mm from apex of costal sclerite to wing tip (including tegula, 3.24 mm), in the paratype DR­14­854, 3.16 mm (including tegula, 3.72 mm), and in DR­14­1440, 3.00 mm (including tegula, 3.44 mm); maximum head width 1.55 mm. Color of integument: Black, including antennal scapes, except tarsomeres, chestnut and trochanters discolored, translucent; head with following parts diffuse yellowish: distal third of clypeus, lower parocular area to tentorial pit, supraclypeal area between antennal alveolus, and labrum; mandibles dark chestnut. Mesonotum black, devoid of yellow markings. Forewing C and R veins and tegulae dark chestnut; pterostigma with translucent spot in middle; wing membrane hyaline. Pilosity: Pale yellow over entire body. Decumbent, pale, minute plumose hairs covering entire face. Erect, unbranched hairs sparse on upper half of frons and increasing in number and length toward vertex; longest hairs on vertex ca. 0.17 mm; ones on scape 0.04 mm. Labial palpi with 3–4 long hairs (0.17–0.18 mm). Longest hairs on labrum 0.22 mm. Mesoscutum with fine, decumbent, unbranched micropilosity a little sparser than on head; erect hairs sparser on discal area and more abundant and longer (0.14 mm) on anterior corners; longest hairs on scutellum 0.18 mm on ventral part of mesepisterna 0.12–0.16 mm. Basal area of propodeum glabrous. Posterior border of tibia III with unbranched hairs, the longest ones ca. 0.18 mm. Only basal half of inner surface of tibia III visible (fig. 14); in wider visible part, corresponding approximately to middle of tibia, keirotrichiate area ca. 0.20 mm wide, posterior rim glabrous (clearly depressed, forming a step), ca. 0.08 mm wide. Externally tibiae partially covered by amorphous substance (pollen?) and air bubbles, but it is possible to verify that the penicillum is normal, as in Plebeia (s.s.); posterior parapenicillum with long, slender hairs and anterior parapenicillum well differentiated with a row of at least eight stiff hairs; rastellum apex visible with at least seven stiff, spinelike hairs. Microtrichia on wing membrane ferruginous and as long as hair interspaces (ca. 0.02 mm). T1 practically glabrous, only some minute hairs on sides; other terga and sterna covered by wings, legs, bubbles, and a whitish substance. Integument: Smooth and shiny as in Proplebeia dominicana ; only piligerous punctures present. Form and proportions: Head 1.2× wider than long (1.55: 1.28, length measured from the apex of clypeus to upper tangent of median ocellus), a little narrower than mesosoma (1.66, measured across mesepisterna). Eyes 2.38× longer than wide (1.00:0.42), slightly convergent below; upper interorbital distance 1.01, maximum distance 1.10 and lower distance 0.89. Malar area a little longer than diameter of scape (0.12:0.10). Clypeus 2.23× wider than long (0.80:0.36), slightly convex. Labrum normal. Distance between clypeus and median ocellus 0.81. Interalveolar distance a little longer than diameter of antennal alveolus (0.19: 0.16), but shorter than alveolorbital distance (0.22). Frons slightly depressed along median line. Distance between lateral ocelli ca. 3.0× diameter of median ocellus and 1.5× ocellorbital distance (0.36:0.12: 0.24). Vertex rounded behind ocelli; preoccipital ridge slightly rounded (as in Plebeia , s.s.). Scape length 5.4× its diameter (0.54: 0.10), and ca. 5 ⁄ 6 distance between antennal alveolus and lateral ocellus (0.64). Flagellum plus pedicel (1.08) ca. 2.0× length of scape; flagellomeres shorter than wide (the second one, 0.08:0.12). Scutellum with distal border semicircular, slightly projecting over metanotum, 2.06× wider than long (0.70: 0.34), basal pit normal (as in Plebeia , s.s.). Forewing 2.32× longer than wide (2.88:1.24), pterostigma 3.43× longer than wide (0.48: 0.14); marginal cell 3.76× longer than wide (0.94:0.25), slightly open at apex, Rs slightly sinuate toward apex; right angle between Rs and Rs + M (ca. 90°); first abscissa of M ca. ⅔ length of first abscissa of Cu (0.42: 0.62) and slightly shorter than Rs + M + second M (0.46). First submarginal cell with limits relatively clear; second submarginal cell completely absent. Hamuli, 5. Tibia III subtriangular (as P. dominicana and Plebeia , s.s.), with posterodistal corner approximately right angled (position of tibiae, and presence of residues and bubbles do not permit reliable measures and details of shape); depressed rim on posterior border of inner surface 2 ⁄ 5 width of elevated keirotrichiate area. Basitarsus III 1.93× longer than wide (0.56: 0.29), slightly broadened toward apex, posterodistal corner right angled.

TYPES: Holotype, worker, specimen AMNH­DR­14­1481 , paratypes, workers AMNH­DR­14­854 and DR­14­1440 , in amber from Miocene of Dominican Republic. Specific mine of origin unknown.

ETYMOLOGY: From the Latin, vetustus, old, ancient.

REMARKS: Poinar (1994 b: 73, fig. 2) referred to specimen AMNH­DR­14­1440 (here designated as a paratype) as Plebeia sp. Michener and Poinar (1996: 354) examined this same specimen and considered it a species distinct from P. dominicana , however these authors disagreed about its placement in the genus Plebeia . Proplebeia vestusta is placed in the genus tentatively, based on the form of the forewing medial cell, the surrounding veins, integument structure, and general body form (which is as robust as in P. dominicana and Plebeia , s.s.) and, mainly, by the depression of the posterior rim of the inner surface of tibia III, with ca. 2 ⁄ 5 the width of the keirotrichiate area. The rastellum and penicillum apparently do not differ from what is seen in the species of Plebeia (s.s.).

In the paratype AMNH­DR­14­854 the clypeus has only a pale yellow stripe along the distal border, a little narrower than the diameter of the scape, and the supraclypeal area is also pale yellow, but the parocular areas are black. In the paratype AMNH­DR­14­1440 only one premarginal, fine, yellow stripe is visible in the clypeus; the other areas are blackish. On both paratypes (extensively surrounded by air bubbles and the legs tangled in such a way that is impossible to examine important characters), the vertex is arched and well elevated above the lateral ocelli, but this condition can be due to the lenticular deformation of the amber. In the remaining characters (e.g., size and proportions of structures), these specimens do not differ from the holotype.

Figures

Figs. 8–10. Forewing, worker; 8. Proplebeia vetusta, sp.n., holotype, specimen, AMNH­DR­14­854; 9. Proplebeia dominicana, specimen AMNH­DR­14­1175; 10. Proplebeia tantilla, sp. n., paratype, specimen AMNH­DR­14­911. Scale = 1.0 mm.

Figs. 11–13. Proplebeia vetusta, sp. n., holotype, AMNH­DR­14­1481, head, detail of mandible, tibia and tarsus III, detail of penicillum and rastellum. Minor scale bar = 1.0 mm (fig. 11), large scale bar = 1.0 mm (figs. 12–13).

Fig. 14. Proplebeia vetusta, sp. n., holotype, AMNH­DR­14­1481. Scale bar = 1.0 mm.

Fig. 22. Photomicrographs of Proplebeia vetusta, sp. n., worker, paratype, AMNH­DR­14­1440. Scale = 1.0 mm.