Mochlomelikertes hoffeinsorum Engel, Breitkreuz, & Ohl, 2014

Engel, Michael S., Breitkreuz, Laura C. V. & Ohl, Michael, 2014, The first male of the extinct bee tribe Melikertini (Hymenoptera: Apidae), Journal of Melittology 2014 (30), pp. 1-18 : 10-13

Mochlomelikertes hoffeinsorum Engel, Breitkreuz, & Ohl , new species

ZooBank: urn:lsid:zoobank.org:act:AF3449F2-26B9-4545-8697-F7427337D6AF

( Figs. 1–13 )

DIAGNOSIS: As for the genus (vide supra).

DESCRIPTION: ♂: Total body length (as preserved) 8.0 mm; forewing length (as preserved) 6.75 mm. Head slightly wider than long, length 2.10 mm, width 2.18 mm. Mouthparts generally typical for corbiculate Apinae; labial palpomeres I and II elongate, somewhat flattened ( Fig. 8 ), palpomere I longest; palpomeres III and IV minute. Mandibles simple, slender, length 0.70 mm, apexes acute, axes of articulations converging anteriorly, closed mandibles crossing at slightly greater than a right-angle ( Fig. 8 ). Malar area virtually absent anteriorly, and only slightly present posteriorly (resulting from anterior convergence of axes of mandibular articulations). Labrum wider than long, medial length 0.18 mm, width 0.58 mm, surface flat, apical margin weakly concave medially ( Fig. 8 ). Clypeus low in profile ( Figs. 5, 6 , 8 ), weakly convex, only slightly extending beyond lower tangent of compound eyes ( Figs. 5, 6 ), without basal prominence or protrusion; fronto-clypeal sulcus very weakly arched apically, dorsal portion of clypeo-facial sulcus (i.e., that portion of epistomal sulcus between the fronto-clypeal sulcus and the anterior mandibular articulation) relatively straight until near anterior mandibular articulation, then angled laterally; anterior tentorial pit in upper half of clypeo-facial sulcus; epistomal sulcus laterally forming broadly obtuse angle. Supraclyeal area slightly longer than wide, low in profile; subantennal sulci slightly longer than antennal torular diameter, meeting epistomal sulcus at angle between frontoclypeal sulcus and upper portion of clypeo-facial sulcus. Antennal toruli separated by less than an individual torular diameter; distance from antennal torulus to compound eye greater than an individual torular diameter; scape long, length 0.90 mm, apical width 0.18 mm; pedicel length 0.17 mm, width 0.17 mm; flagellum with 11 flagellomeres ( Figs. 5–7 ); individual flagellomeres slightly longer than wide except apicalmost flagellomere which is much longer than wide; first flagellomere length 0.23 mm, width 0.15 mm; second flagellomere length 0.23 mm, width 0.15 mm; third flagellomere length 0.23 mm, width 0.15 mm; fourth flagellomere length 0.22 mm, width 0.15 mm; fifth flagellomere length 0.20 mm, width 0.15 mm; sixth flagellomere length 0.20 mm, width 0.15 mm; seventh flagellomere length 0.20 mm, width 0.15 mm; eighth flagellomere length 0.20 mm, width 0.15 mm; ninth flagellomere length 0.23 mm, width 0.17 mm; tenth flagellomere length 0.27 mm, width 0.17 mm; eleventh flagellomere length 0.33 mm, width 0.17 mm. Compound eye slightly wider than gena in lateral profile; compound eye length 1.67 mm, width 0.80 mm; median ocellus at upper tangent of compound eyes, diameter 0.20 mm; distance from median ocellus to lateral ocellus 0.08 mm, lateral ocellus to compound eye 0.22 mm, between lateral ocelli 0.33 mm, ocellar triangle to preoccipital ridge 0.28 mm; preoccipital area rounded ( Fig. 7 ). Pronotum short, declivitous, without defined transverse, dorsal ridge or well-defined posterior, dorsal-facing surface along mesoscutal border; pronotal lateral ridge absent; mesoscutum anterior border broadly rounded, anterior lip gently curving to meet posterior pronotal margin, not high or overhanging pronotal border, median and parapsidal lines scarcely impressed; mesoscutum length 1.50 mm; tegula large, elongate-ovoid, anteriorly broadly rounded, posteriorly elongate and acutely rounded, nearly two-thirds length of mesoscutum; intertegular distance 1.33 mm; mesoscutellum with axillae large, axillar medial corners separated by slightly less than axillar width; transscutal articulation deeply impressed (i.e., mesoscutal-mesoscutellar sulcus deeply impressed); laterally from axilla, mesoscutellar margin weakly arches medioposteriorly before posterior margin projects posteriad into elongate extension ( Figs. 3, 4 , 9–11 ), with depressed area in line with lateral margin before extension apparently demarcating more typical area of posterior margin ( Figs. 10, 11 ); mesoscutellar posterior margin medially elongate to form tongue- or lever-like extension, process greatly elongate and projecting over metanotum, propodeum, and anterior portions of metasoma (projecting over at least basal three metasomal segments), with projection slightly longer than remainder of mesosoma ( Figs. 3, 4 , 9 ), and apex of extension broadly rounded; mesoscutellum length to beginning of depressed area 0.47 mm, projection length 2.20 mm, width 0.50 mm, total mesoscutellum length (mesoscutellar disc and entire length of extension) 2.67 mm; metanotum unmodified; propodeum strongly declivitous, basal area longer than metanotum; pleura generally unmodified, hypoepimeral area small. Forewing with basal vein (i.e., first free abscissa of M) basad cu-a, separated by four times vein width; basal vein relatively straight; first free abscissa Rs originating near apex of prestigma, distinctly less than one-half length of basal vein; pterostigma relatively large, trapezoidal, apical width 1.5 times basal width, length slightly more than four times basal width, apically tapering within marginal cell, border within marginal cell relatively straight; r-rs meeting pterostigma near midpoint, r-rs long, about as long as maximum width of pterostigma; only two submarginal cells present, owing to loss of 1rs-m; first submarginal cell much smaller than second submarginal cell, strongly arched in shape, appearing horsehead-shaped; Rs+M angled posteriorly, with second free abscissa Rs originating such that Rs+M subequal to second abscissa M (i.e., free abscissa of M beyond Rs+M), abscissa of Rs strongly angulate in basal third (much like in many first submarginal cells among corbiculate apines: e.g., Thaumastobombus andreniformis Engel , Melissites trigona Engel , Bombus randeckensis Wappler & Engel : Engel, 2001a; Wappler et al., 2012); 1m-cu relatively straight, short, about as long as first free abscissa Rs, thus first medial greatly narrowed apically; Rs+M and second free abscissa of M (i.e., between Rs+M and 1m-cu), forming a relatively straight line, angled posteriorly; M at point of 1m-cu extending straight toward wing apical margin and parallel with longitudinal axis of wing; second submarginal cell elongate, length 3.5 times width; 2rs-m relatively straight; 2m-cu relatively straight, meeting second submarginal cell near apex, basad 2rs-m by seven times vein width; marginal cell long, broad basally, tapering gently along length to acutely rounded apex, apex offset from anterior wing margin by vein width, apex minutely appendiculate; wing membrane not papillate, with uniform distribution of microtrichia; hind wing with normal complement of veins; six distal hamuli arranged in a regularly-spaced series; well-developed jugal lobe present. Malus of protibial strigilis arched, with broad velum, apical rachis short and simple; mesotibia only slightly longer than mesobasitarsus, slightly swollen; mesobasitarsus length 2.75 times width, slightly swollen like mesotibia ( Fig. 12 ); metatibia without corbicula ( Fig. 13 ), broadened apically, with outer surface slightly swollen ( Fig. 13 ) with scattered setae over entire surface (rather than depressed and with distinctly broad asetose area as in female workers), inner surface with keirotrichia, with keirotrichiate zone not elevated, running from base to near apex, separated from posterior border by distance less than one-third width of keirotrichiate zone; apical polished area beyond keirotrichiate zone with subapical, transverse row of four, short, apically-blunt peg-like setae; metatibia length 2.07 mm, maximum width 0.73 mm; single metatibial spur present, spur minutely serrate; metabasitarsus roughly subquadrate ( Fig. 13 ), slightly longer than wide, length 0.73 mm, width 0.57 mm, length about 1.3 times width, not distinctly swollen, apical margin weakly concave; pretarsal claws of all legs cleft. Metasoma generally unmodified, seven exposed terga; sterna with apical margins straight; gonostyli broadly rounded apically.

Pubescence generally pale in appearance; head with short to minute, simple setae largely appressed on face, slightly longer around clypeal apex; setae more numerous on clypeus than on remainder of face; setae becoming slightly longer and more erect on vertex posterior to ocelli ( Figs. 5–7 ); postgena with scattered setae similar to those on vertex ( Fig. 8 ); mandible with few simple, erect setae, mostly along ventral margin; labrum with scattered, long, simple, suberect setae; labial palpomere II with long, simple, posteriorly-directed setae along lateral and apical borders, surface otherwise with minute, appressed, simple setae ( Fig. 8 ). Mesosoma with generally sparse, short pubescence; pronotal lobe with dense, short, erect setae; mesoscutum with sparse, erect setae with minute apical branches, such setae slightly longer and more numerous anteriorly, particularly anterolaterally ( Fig. 9 ); tegula with minute, fine, appressed to suberect setae scattered over surface; mesoscutum with long, erect, apically minutelybranched setae borne laterally and anterior to depressed area at base of extension, with dorsal surface of extension bearing dense, long, apically-branched setae ( Figs. 9–11 ), such setae present laterally albeit less numerous, and similar setae present on ventral surface of extension although more sparsely scattered and shorter than comparable setae on dorsal surface ( Fig. 10 ); metanotum with scattered, short, simple, erect setae; propodeum with basal area glabrous, lateral surfaces with scattered, short, simple, erect setae; pleura with sparsely scattered, erect to suberect, long, simple setae — except hypoepimeral area with minute, simple, appressed setae; pubescence of legs generally sparsely scattered and erect to suberect, except as follows: setae of protibia and protarsus distinctly more numerous than profemur, individual setae simple, suberect, stiff, and longer than width of associated podite; mesotrochanter with narrow band of dense, short setae on ventral surface; mesofemur with sparse, simple, suberect setae on most surfaces, except similar narrow band of short, dense setae on posteroventral border; mesotibia outer surface with numerous elongate, simple setae ( Fig. 12 ), such setae longer than width of mesotibia, other surfaces with distinctly shorter, erect, somewhat blunt, simple setae; mesobasitarsus similar to mesotibia except simple elongate setae along posterior border and posterior portion of outer surface, and remainder of surface with shorter, simple, erect setae ( Fig. 12 ); metatrochanter with ventral, narrow brush of dense, short setae; metafemur with ventral surface glabrous, remaining surfaces with sparse, suberect, short, simple setae; metatibia outer surface with scattered erect, elongate setae ( Fig. 13 ), individual setae with exceedingly minute branches in apical third to quarter of length, inner surface glabrous except for zone of keirotrichia (vide supra); metabasitarsus with outer surface bearing setae similar to outer surface of metatibia over its posterior half ( Fig. 13 ), with anterior half largely devoid of setae, and inner surface with comb rows composed of stiff, apically-directed, simple setae. Metasoma with sparse, short to minute, simple, appressed to suberect setae; terga IV through VII apically also with scattered, erect, short setae; gonostyli with minute, simple setae apicolaterally.

Integument generally faintly and minutely imbricate or smooth throughout; brown to dark brown where evident, otherwise integument microscopically separated from amber to form reflective, silvery metallic sheen common in Baltic amber inclusions; integument of head apparently brown except antenna and mouthparts lighter, no evidence of areas with possible maculation during life with exception of extreme clypeal apical margin distinctly white (either white or perhaps yellow in life); mesosoma apparently dark brown with legs somewhat lighter; metasoma apparently brown throughout; wing membranes hyaline and without areas of infuscation, veins dark brown to black.

♀: Unknown.

☿: Unknown.

HOLOTYPE: ♂, Baltic amber [succinite], middle Eocene (Lutetian), Blaue Erde; in the Hoffeins Collection (coll. No. CCHH 1766-1 ) to be deposited in the Senckenberg Deutsches Entomologisches Institut , Müncheberg, Germany.

ETYMOLOGY: The specific epithet honors Christel and Hans Werner Hoffeins, collectors of this and many other spectacular inclusions and who initially recognized its significance and drew it to our attention.

Figures

Figures 1–2. Photographs of holotype (CCHH 1766-1) male of Mochlomelikertes hoffeinsorum, new genus and species. 1. Dorsal oblique view. 2. Ventral oblique view.

Figures 3–4. Photographs of holotype (CCHH 1766-1) male of Mochlomelikertes hoffeinsorum, new genus and species. 3. Left lateral view. 4. Right lateral oblique view.

Figures 5–6. Photograph and illustration of head of holotype (CCHH 1766-1) male of Mochlomelikertes hoffeinsorum, new genus and species. 5. Left oblique view. 6. Illustration of head as preserved.

Figures 7–8. Photographs of head of holotype (CCHH 1766-1) male of Mochlomelikertes hoffeinso- rum, new genus and species. 7. Dorsal view. 8. Ventral apical oblique view showing mouthparts.

Figures 9–11. Holotype (CCHH 1766-1) male of Mochlomelikertes hoffeinsorum, new genus and species. 9. Photograph of dorsal view of mesosoma. 10. Photograph of left lateral view of mesoscutellum and its posterior extension. 11. Illustration of mesosomal dorsum.

Figures 12–13. Photographs of legs of holotype (CCHH 1766-1) male of Mochlomelikertes hoffeinsorum, new genus and species. 12. Apex of mesotibia and entire mesotarsus and mesopretarsus. 13. Metafemur, metatibia, metatarsus, and metapretarsus (with portions of left mesotibia and mesotarsus in foreground).