Notes on the stingless bee genera Scaura and Geotrigona (Hymenoptera: Apidae)

Brief notes are presented on the classifications of Scaura Schwarz and Geotrigona Moure. A new subgeneric system is proposed for Scaura in which three subgenera are recognized: Scaura Schwarz, s.str.; Scauracea Engel, new subgenus; Schwarzula Moure. Likewise, a new subgenus is proposed in Geotrigona as Chthonotrigona Engel, new subgenus.

Two new genera of South American Eulonchopriini (Hymenoptera: Colletidae)

Two new genera are described and figured for South American eulonchopriine bees. Apatosigynes Engel, new genus, is described for the eastern and southern Brazilian Apatosigynes meloi Engel, new species, and the northern Peruvian Leioproctus (Nomiocolletes) simplicicrus Michener (previously placed in Eulonchopria Brèthes). The genus is differentiated from Eulonchopria most notably by the absence of a preoccipital carina or lamella, absence of a pronotal carina, simple axillae, a rugose propodeum, and narrow metasomal bands. Similarly, Mimozibyne Engel, new genus, is described for the Argentine and Paraguayan L. (Perditomorpha) eulonchopriodes Michener. Mimozibyne is easily confused with Perditomorpha Ashmead or an enigmatic Eulonchopria, and is distinguished on the basis of two submarginal cells (as in Perditomorpha), coarse punctation, presence of yellow metasomal bands with raised margins, and more squat antennal flagellomeres. The following new combinations are established: Apatosigynes simplicicrus (Michener) and Mimozibyne eulonchopriodes (Michener).

A key to the species of Nanoplebeia, with descriptions of four new species (Hymenoptera: Apidae)

Four new species of the subgenus Nanoplebeia Engel (genus Plebeia Schwarz) are described and figured as: Plebeia (Nanoplebeia) pleres Engel, new species, from Venezuela; P. (N.) asthenes Engel, new species, from Bolivia; P. (N.) orphne Engel, new species, from Ecuador and Peru; and P. (N.) chondra Engel, new species, from Ecuador. A key is presented to the species of the subgenus.

Stingless bees in Miocene amber of southeastern China (Hymenoptera: Apidae)

Among the many inclusions from the exceptionally rich fossiliferous amber of Zhangpu, China (Middle Miocene: Langhian), stingless bees (Apinae: Meliponini) are particularly common, analogous to the merely slightly older amber sites of Mexico and the Dominican Republic. While there is a large number of workers in Zhangpu amber, only two species are represented. The systematics and morphology of the tribe Meliponini is outlined, including a revision to terms of orientation and direction when discussing surfaces and features of appendages, all in order to better discuss the traits of the fossils as well as place them into a broader context in the global systematics of stingless bees. The two amber species are representative of two Old World genera of Meliponini: Tetragonula Moure and Austroplebeia Moure. While the former is widespread across southern Asia, Malesia, Papuasia, and Australia, the latter is today known only from New Guinea and Australia. Neither genus occurs in the environs of Zhangpu today. Tetragonula (Tetragonula) florilega Engel, new species, is a generally typical species of the subgenus although it intermingles traits otherwise found in two large species groups of non-Australian Tetragonula s.str. The species of Austroplebeia from Zhangpu is sufficiently distinct to place in a new subgenus, Anteplebeina Engel. Austroplebeia (Anteplebeina) fujianica Engel, new species, shares a long list of character states with Austroplebeia s.str., including the presence of yellow maculation on the face, mesoscutum, mesoscutellum, and metepisternum, found only in this clade among Asiatic Meliponini. Nonetheless, the species differs in the length of the malar space and various features of wing venation. Keys are provided to the genera in Zhangpu amber and the subgenera of both genera. The diversity of stingless bees in amber is discussed, as well as the presence of these two fossils in the Middle Miocene of mainland Asia in relation to prior divergence time estimates, phylogenetic relationships, as well as the paleogeography of the region and potential biogeographic hypotheses. The biological association of stingless bees with resins, particularly the collection of dipterocarp resins, is discussed as Zhangpu amber is a Class II resin likely produced by an extinct species of Dipterocarpaceae (Malvales). Also discussed are the ecological preferences of modern Tetragonula and Austroplebeia relative to the reconstructed paleoenvironment of the Zhangpu amber rainforest. Emendations to the classification of Meliponini are appended, with the following new taxa proposed: Atrichotrigona Engel, new subgenus of Axestotrigona Moure; Lispotrigona V.H. Gonzalez & Engel, new subgenus of Nannotrigona Cockerell; Asperplebeia Engel, new genus; Nanoplebeia Engel, new subgenus of Plebeia Schwarz; Aphaneuropsis Engel, Koilotrigona Engel, Necrotrigona Engel, Dichrotrigona Engel, Nostotrigona Engel, Ktinotrofia Engel, all new subgenera of Trigona Jurine; Chapadapis Engel, new subgenus of Schwarziana Moure. The following higher groups are also established: Hypotrigonina Engel, new sutribe; Heterotrigonitae Engel, new infratribe; Trigoniscitae Engel, new infratribe.

New genera of melikertine bees with facial modifications in Baltic amber (Hymenoptera: Apidae)

The tribe Melikertini (Apinae: Corbiculata) is an extinct group of highly eusocial bees presently known only from early to late Eocene deposits of Eurasia. Among melikertine diversity are a suite of species peculiar for their rather dramatic morphological specializations, at least in relation to modern corbiculate Apinae. Here we document two new species of Melikertini and utilize standard X-ray as well as propagation phase contrast synchrotron computed microtomography to further explore these and previously known species, revealing finer details not previously observable from melikertines. Accordingly, some species placed in the genera Melikertes Engel and Succinapis Engel are reëvaluated. Three new genera are characterized, as well as some further facial modifications not previously known for the tribe. New taxa and taxonomic changes presented are: Aethemelikertes emunctorii Engel, new genus and species; Haidomelikertes uraeus Engel, new genus and species; H. proboscidea (Engel), new combination; Amelikertotes Engel, new genus; Amelikertotes clypeata (Engel), new combination. Additionally, new records and taxonomic notes on other Baltic amber and Eocene bees are appended, with the following nomenclatural changes established: Palaeomacropis Michez & Nel is recognized as a megachiline rather than a melittid, and is transferred to Megachilinae where it is a new junior synonym of Ctenoplectrella Cockerell (new synonymy); Ctenoplectrella eocenica (Michez & Nel), new combination; a key is provided to species of Ctenoplectrella; Thaumastobombina Engel, new subtribe in Electrapini; Thnetobombus Engel, new subgenus in Protobombus Cockerell; Mesomelissa Engel, new subgenus in Electrapis Cockerell; Electrapis (Euglossopteryx) biesmeijeri (De Meulemeester et al.), new combination. A list of Eocene bees is appended.

The first case of gynandromorphy in Centris pallida (Hymenoptera: Apidae: Centridini)

A case of gynandromorphy is reported for the first time for Centris pallida Fox, a bee species found predominantly in the deserts of the southwestern United States and northern Mexico. This specimen marks only the second report of a gynandromorph within the tribe of oil-collecting bees, Centridini, and the first Centris Fabricius. The specimen exhibits mosaic gynandromorphy, with male and female characteristics randomly distributed throughout the body. Males of C. pallida are morphologically and behaviorally dimorphic (a large and a small male morph), and the male characteristics of the gynandromorph are more similar to the large male morph, which is also most similar in head width to the specimen.

First records, phenology, habitat, and host-plant associations of Macrotera opuntiae (Cockerell) (Hymenoptera: Andrenidae) in Montana

Macrotera (Cockerellula) opuntiae (Cockerell) is a minute bee oligolectic on cacti and one of the few stone-nesting bee species. We document the first records of M. opuntiae in Montana, USA, a considerable range expansion from where this species was previously known in Colorado. We briefly describe the habitat and host-plant (cacti) associations, and the activity period of M. opuntiae adults in Montana. A new state record for Nebraska and new records for western Colorado are also reported.

Two new species of Andinopanurgus (Hymenoptera: Andrenidae: Panurginae), with a description of the female of A. amyae

Two new species of Andinopanurgus Gonzalez & Engel are described: Andinopanurgus chirosimpson Packer, new species, from northwest Argentina extends the range of the genus south by more than 2000 km and A. lynnae Packer, new species, from Peru. The new species seem to belong to Gonzalez & Engel’s “guarnensis species group” but differ from it in the highly modified setae on S4, which are divided into two to four branches (in A. chirosimpson, the four-branched ones of which look like a thumbless hand and are the source of the specific epithet) to two to five branches (in A. lynnae). The female of A. amyae (Gonzalez & Engel) is described for the first time.

Record of Anthophora (Clisodon) terminalis in a wooden trap-nesting block and comparison to available nesting information (Hymenoptera: Apidae)

Bee nesting substrate choice can influence habitat use, conservation effort efficacy, and population or landscape-use modeling, but information on nesting sites are often scattered in the literature. Here we bring together the available information on nests of a widespread bee, Anthophora (Clisodon) terminalis Cresson, and describe an unusual new nesting substrate use for this species.

A new vernal species of Hesperapis from the lower Midwestern United States (Hymenoptera: Melittidae)

A new species of vernal Hesperapis Cockerell (Melittidae: Dasypodainae: Hesperapini) is described and figured from localities spanning Texas, Oklahoma, and southern Kansas in the United States. Hesperapis (Carinapis) infuscata Engel & Michez, new species, is distinguished from its relatives in subgenus Carinapis Stage and particularly the carinata species group, to which it belongs. The species is most notable for the apically infuscate wings and is possibly specialized (broadly oligolectic) on Gaillardia Foug., Helianthus L., Ratibida Raf., and Rudbeckia L. (Asteraceae).