Glyptapini Cockerell

Engel, Michael S. & Xie, Jiaying, 2024, The Bee Fauna Of Eocene Fushun Amber (Hymenoptera: Apoidea), Bulletin of the American Museum of Natural History 2024 (469), pp. 1-81 : 10-15

Tribe Glyptapini Cockerell

The tribe Glyptapini currently comprises a single genus, Glyptapis Cockerell (figs. 2, 3). When the genus was first described Cockerell wrote (1909a: 13), “So far as I can judge, Glyptapis and Ctenoplectrella stand near the stem-form of the Megachilidae , but so remote from the modern members of that group that they at least form a distinct subfamily, Glyptapinae . Their nearest relative in the modern fauna appears to be Ctenoplectra .” Cockerell was prescient in his conclusion that Glyptapis and Ctenoplectrella were close to Megachilidae , although his comment regarding the unrelated Ctenoplectra Smith misdirected subsequent researchers for nearly a century. As we understand Ctenoplectra today, the genus is a specialized group of Apidae , until recently classified as the apine tribe Ctenoplectrini ( Michener, 2007) , and currently constituting with Tetrapediini the subfamily Ctenoplectrinae ( Engel et al., 2021b) , which is considered related to Xylocopinae ( Bossert et al., 2019) . Ctenoplectra has followed a tortuous path to find its current resting place next to the xylocopines, and Glyptapis and Ctenoplectrella were dragged through this journey merely by association. Cockerell (1920) established a family Ctenoplectridae , which he felt was close to Macropis Panzer , thereby associating the group with more modern concepts of Melittidae . Michener (1944) followed suit and placed Ctenoplectra as a subfamily of Melittidae , although made no mention of the putative fossils. Based on nothing more than the offhand note of an affinity between these fossil genera and Ctenoplectra, Zeuner and Manning (1976) asserted both genera to be melittids, a similar action followed by Michener and Greenberg (1980) when returning ctenoplectrines to family status. One of us (M.S.E.) similarly followed this precedent when discussing the fossil history of Megachilidae ( Engel, 1999a) , although this was before extensive examination of material for the genus. Eventually, Ctenoplectra was found to be nested within the Apidae ( Roig-Alsina and Michener, 1993; Silveira, 1993), and the first suspicions of a misconnect between the fossils and Ctenoplectra were alluded to when Roig-Alsina and Michener (1993: 160) wrote that fossil “forms assigned to the Ctenoplectrini may be misplaced.” Engel (2001) was the first to recognize that Glyptapis and Ctenoplectrella were early diverging groups of Megachilinae , bringing the journey nearly full circle and echoing Cockerell (1909a). Engel (2001) initially placed them as independent subtribes in an expanded Osmiini before ultimately recognizing that they should be removed as distinct tribes ( Engel, 2005; Engel and Perkovsky, 2006). In fact, their removal was the beginning of a progressive narrowing of the circumscription of Osmiini to achieve monophyly, eventually achieved through the later removal of Aspidosmia Brauns , Noteriades Cockerell , Ochreriades Mavromoustakis , Afroheriades Peters , and Pseudoheriades Peters (e.g., Michener, 2007; Praz et al., 2008; Gonzalez et al., 2012, 2019).

Perhaps the most immediately distinctive features of Glyptapis are the craterlike punctures of the mesosoma (figs. 2B, 3, 4), the areolate propodeum (figs. 2B, 3, 4), the hirsute compound eyes (fig. 2A), and the large edentate margin to the mandible (fig. 5I–J). These characters certainly make it possible to easily recognize the bees among fossil Apoidea , but there are numerous other interesting combinations of traits present in the groups, beyond just the aforementioned metatibial scopa. Continued study of these bees over the past 20 years and the availability of the scans reproduced here permit a more thorough and corrected diagnosis for the tribe.

DIAGNOSIS: Integument apparently without maculation and nonmetallic (integumental coloration poorly preserved in available fossils).

FEMALE. Mandible with single apical tooth and long edentate margin apically composed of expanded trimmal extension (fig. 5I–J); fimbrial ridge present on mesal surface and paralleling apical edentate margin (fig. 5I); interdental laminae lacking (fig. 5I, K). Malar space linear (fig. 5A–C). Maxillary palpus tetramerous. Labial palpus tetramerous (fig. 5H); palpomeres I and II flattened, elongate, palpomere I about 0.5× length of palpomere II; palpomere II with several erect stiff setae ventrally; palpomere III projecting obliquely from axis of palpomere II; ventral (posterior) surface of glossa with longitudinal groove, forming a glossal canal with inner longitudinal ridge and bordered by annulate, ectal surfaces of glossa (fig. 5G). Clypeus somewhat flattened, extending below lower tangent of compound eyes (fig. 5A–C); clypeus apical margin covering labral base, thus labroclypeal articulation obscured (fig. 5A–C). Single subantennal sulcus directed to outer margin of antennal torulus (fig. 5A). Juxtantennal carina absent (fig. 5A). Compound eyes hirsute. Posterior margin of vertex gently concave; preoccipital area sharply angled above but not carinate, otherwise rounded (fig. 5E, F).

Pronotal collar virtually absent, with posterior border blending uninterrupted onto dorsal surface without transverse ridge medially (in profile slope continuous and without anterior, transverse ridge demarcating dorsal-facing surface comprising collar relative to lower anterior neck), with transverse dorsal ridge carinate laterally (effaced medially) and extending across pronotal lobe without dorsolateral angle (fig. 4B) (dorsolateral angle present in Dioxyini except Prodioxys Friese ), without dorsolateral ridge extending vertically across lateral surface (fig. 4B) (present in Dioxyini ).

Mesoscutum broadly rounded anteriorly (figs. 3C, 4C), raised above pronotal posterior margin, with deep craterlike punctures/foveae (figs. 2B, 3B, C, 4B–E) (also present on mesoscutellum and upper mesepisternum); parapsidal lines linear; preaxilla vertical and asetose (as in Dioxyini and Anthidiini ); mesoscutalmesoscutellar sulcus deeply impressed, with small, medial, V-shaped notch on mesoscutellum; mesoscutellum low, rounded, posterior margin narrowly vertical with transverse row of small areolae, posterior margin not extending over metanotum; axillae simple (figs. 2B, 3D, 4E); metanotum sloping, without medial tubercles or spines (metanotum tuberculate or spinous in Dioxyini ); basal area of propodeum sloping, asetose, areolate (figs. 2B, 3D, 4B, D, E); omaular ridge carinate (fig. 4B); scrobal sulcus absent; preepisternal sulcus absent; mesepisternum areolate (fig. 4B); dorsal lamella of metepisternum absent.

Forewing (refer to Engel, 2001) with pterostigma proximal to r-rs as long as or slightly longer than pterostigmal width; pterostigmal length 2× or more its basal width; prestigma more than 2× as long as broad; basal vein (1M) arched, thus orthogonal to 1Cu (as in Ctenoplectrellini and the new tribe described below); marginal cell apex acutely rounded on anterior wing margin; two submarginal cells; 1m-cu and 2m-cu entering second submarginal cell, i.e., 2rs-m proximal to 2rs-m; hind wing with six distal hamuli.

Protibial calcar (fig. 6) with anterior ridge on rachis bordering velum (fig. 6D) (as in Anthidiini ), malus simple, short (fig. 6D), less than 0.5× length of velum, apical margin of velum simple (rachis and apex of velum with serrations in Anthidiini and Osmiini ); tibiae not spiculate; pro- and mesotibiae with apical outer spine (fig. 6A), spine fainter on protibia; mesotibial spur long, slender, minutely ciliate (fig. 6); metabasitibial plate absent; metatibial scopa present (fig. 7) (as in Ctenoplectrellini and the new tribe described below; absent in other megachiline tribes); metatibial spurs long, slender, minutely serrate to minutely ciliate (fig. 7); pretarsal claws with short inner ramus (figs. 6, 7D); arolium present (figs. 6, 7).

Metasomal scopa present; sting and associated structures well developed (vestigial in Dioxyini ).

MALE. Unknown.

REMARKS: It is worth noting here a clarification regarding the publication and date from which the name Glyptapis and that of its type species, Glyptapis mirabilis Cockerell , were first made nomenclaturally available. More than 20 years ago, one of us (M.S.E.) followed the assertion of Zeuner and Manning (1976) that the first usage of the names Glyptapis and G. mirabilis were in Cockerell’s (1909b) paper in The Entomologist, and his more extensive descriptions of the genus, its type species, and the remaining species of the genus appeared subsequently in Schriften der physikalischökonomischen Gesellschaft zu Königsberg ( Cockerell, 1909a). However, examination of the prefatory material to volume 50 of the Schriften reveals at the end of the table of contents an outline of the dates of publication for the various numbers constituting the volume. Cockerell’s (1909a) article was published 20 September 1909, while the article that Zeuner and Manning (1976) considered as the taxon name’s first usage—erroneously it turns out—was not released until December 1909. Thus, the genus Glyptapis and its type species were made available in the article Cockerell intended ( Cockerell, 1909a) and his usage of the names later that year in The Entomologist was merely a subsequent mention rather than the place from which the names were made available. Why Zeuner and Manning (1976) made such a reversal of precedence for the names is unclear but wrong based on currently available evidence. The same order of precedence applies to the name Ctenoplectrella .