Amelikertotes Engel, 2021

Engel, Michael S. & Davis, Steven R., 2021, New genera of melikertine bees with facial modifications in Baltic amber (Hymenoptera: Apidae), Journal of Melittology 2021 (103), pp. 1-52 : 26-32

Amelikertotes Engel , new genus

ZooBank: urn:lsid:zoobank.org:act:C88F964D-190C-4588-8C06-E4A93650CEAF

TYPE SPECIES: Melikertes clypeatus Engel, 2001a.

DIAGNOSIS: This genus is most similar to Melikertes but can be readily distinguished by the flared and medially cleft apical margin to the clypeus ( Figs. 30–39 , 51–62 ). In addition, the fringe of setae on the posterior margin of the metatibia is shorter than those in Aethemelikertes or Haidomelikertes .

DESCRIPTION: ⚲: Small bees, ca. 3.1–3.4 mm in length; head wider than long, upper interorbital distance greater than compound eye length. Mandible with shallow incision for single blunt preapical tooth along upper quarter of apical margin; axes of mandibular articulations converging anteriorly such that closed mandibles overlap at slightly obtuse angle and do not obscure or limit forward movement of labrum; malar space linear; labrum flat, slightly broader than medial length, broadly U-shaped, margins forming a continuous arc between basolateral corners, margin entire (i.e., not emarginate or concave), surface with sparsely scatered suberect to erect setae, without lateral with fringe; clypeus without basal protrusion, disc weakly convex, apical margin flared anteriorly and projecting obliquely over labral articulation, extending forward by about 1.75× median ocellar diameter, apical margin with deep, U-shaped medial concavity; epistomal sulcus laterally forming obtuse angle; upper torular tangent slightly below head midlength; intertorular distance about 1.65× torular diameter; scape shorter than torulocellar distance; first flagellomere about as long as wide, slightly longer than second flagellomere, second and third flagellomeres equal in length, each wider than long; ocelli high on vertex, situated well above upper tangent of compound eyes; vertex unmodified (no depressions or ridges); preoccipital area rounded; gena slightly narrower than compound eye in profile. Mesoscutum with anterior border low, broadly rounded; tegula elongate-ovoid; mesoscutellum low, rounded, not projecting over metanotum and base of propodeum; propodeum with sloping basal area distinct from vertical posterior surface. Forewing with prominent, subtriangular pterostigma, pterostigma about 2.5× as long as maximum width, margin inside marginal cell sloping to costal margin; marginal cell broad along entire length, broadly rounded apically, appendiculate, apex offset from costal margin by about 3–4× vein width; basal vein straight, slightly basad 1cu-a; three submarginal cells present (1rs-m present), second submarginal cell trapezoidal, anterior border (3Rs) significantly shorter than r-rs, r-rs distad widest point and midlength of pterostigma; third submarginal cell about as broad as first submarginal cell; 1rs-m faintly arched, 2rs-m weakly arched in posterior half, thus anterior border of third submarginal cell shorter than posterior border of same cell, anterior border of third submarginal cell (4Rs) shorter than combined lengths of r-rs and 3Rs; 1m-cu angulate apically near second submarginal cell, entering second submarginal cell near cell midlength; anterior margin of hind wing with five distal hamuli arranged in an evenly spaced series; wing membranes hyaline clear; veins dark brown. Metatibia slender, elongate, posterior margin gently convex and slightly widening in apical two-thirds; surface of corbicula not depressed; posterior margin with fringe of long, plumose (minute branches along length of setal rachis) setae, such setae slightly shorter than to about as long as metatibial width, anterior margin with few simple setae and bristles, largely apically, corbicular surface with sparsely scatered, erect, fine, simple setae; inner surface with keirotrichiate zone covering most of surface except exceedingly narrow, posterior, slightly depressed glabrate zone and a rectangular apical glabrate zone, length of apical glabrate zone slightly less than apical width of metatibia; rastellum composed of stiff bristles along nearly entire inner apical width of metatibia; single metatibial spur present; metabasitarsus with auricle present on proximal surface facing apex of metatibia; metabasitarsus rectangular, longer than wide, margins roughly parallel, apical margin slightly concave, inner surface with abundant, elongate, suberect, simple bristles; pretarsal claws with minute inner subapical ramus; arolium present. Metasoma broad, ovoid, sparsely setose; metasomal sterna unmodified; sting present.

ETYMOLOGY: The new genus-group name is a combination of the Greek a – (ᾰ –, alpha privativum), meaning, “not”; Melikertes , type genus of the tribe; and the feminine suffix – tēs [– της, denoting a “quality of” or “state of being of”, genitive – τητος; related to feminine – ótita (– ότητα), forming abstract nouns, derived from – tēta (– τητᾰ)]. The gender of the name is feminine.

Figures

Figures 30–33. PPC-SRµCT scan of worker of Amelikertotes clypeata (Engel), new combination; upper right worker from figure 29. 30. Right lateral view. 31. Left lateral view. 32. Ventral view. 33. Dorsal view. Note that scan resolution was insufficient to resolve most fine setae.

Figures 34–39. PPC-SRµCT scan of worker head of Amelikertotes clypeata (Engel), new combination; upper right worker from figure 29. 34. Dorsal view. 35. Ventral view. 36. Facial view. 37. Posterior view. 37. Right lateral view. 38. Left lateral view. Arrows point to flared and cleft clypeus. Note that scan resolution was insufficient to resolve most fine setae.

Figures 51–56. PPC-SRµCT scan of worker of Amelikertotes clypeata (Engel), new combination; lower left worker from figure 29. 51. Left lateral view. 52. Dorsal view. 53. Outer (prolateral) view of hind leg. 54. Inner (retrolateral) view of hind leg. 55. Ventral view. 56. Right lateral view. Scale bar at right for 53 and 54, scale bar in center for 51, 52, 55, and 56. Note that scan resolution was insufficient to resolve most setae of the body and legs (e.g., posterior fringe of fine setae on metatibia is not resolved).

Figures 57–62. PPC-SRµCT scan of worker head of Amelikertotes clypeata (Engel), new combination; lower left worker from figure 29. 57. Facial view. 58. Right lateral view. 59. Posterior view. 60. Left lateral view. 61. Ventral view. 62. Ventral view with mandibles removed to reveal labrum. Scale bar in center for 57–60, scale bar at botom left for 61 and 62. Note that scan resolution was insufficient to resolve most fine setae.