Schwarzia, , Eardley, 2009

Bossert, Silas, Copeland, Robert S., Sless, Trevor J. L., Branstetter, Michael G., Gillung, Jessica P., Brady, Seán G., Danforth, Bryan N., Policarová, Jana & Straka, Jakub, 2020, Phylogenomic and Morphological Reevaluation of the Bee Tribes Biastini, Neolarrini, and Townsendiellini (Hymenoptera: Apidae) With Description of Three New Species of Schwarzia, Insect Systematics and Diversity 4 (6), No. 1, pp. 1-29 : 24

Schwarzia

In the initial description of Schwarzia, Eardley (2009) recognized it as Biastini and proposed a particularly close relationship to Biastes . This was a remarkably accurate assessment based on morphological examination, which we herein confirm with molecular data. In fact, Schwarzia is sister group to Biastes as proposed above ( Figs. 1 and 2 ). In a second account of Schwarzia, Bossert (2019) described a second species and reevaluated the morphology of the genus. Some characters that were previously thought to be diagnostic for Biastini (except Rhopalolemma ), such as the bidentate mandibles, did not hold up for the second species. However, other newly discovered features, including the reduced number of flagellomeres in males and the broad shape of the labrum, supported its morphological affinity to Biastes .

The description of three new species of Schwarzia herein demolishes one of these re-defined features. Both Schwarzia icipensis and

S. lualenyiensis possess 11 flagellomeres in the male. Interestingly, there is also a single species of Biastes with 11 flagellomeres ( B. brevicornis ), whereas males of other Biastes possess 10. In Schwarzia , this trait is phylogenetically conserved, as species with 11 flagellomeres in males are sister taxa. The other three Schwarzia species , all of which have only 10 flagellomeres in the male, form the sister clade to this grouping ( Figs. 1 and 2 ). Based on this, we decided to continue assigning female first names only to those new species of Schwarzia that exhibit this trait. We further reevaluated the shape of the labrum of Schwarzia and discovered a shared morphological feature with Biastes . In both Biastes and Schwarzia , the apical margin of the labrum is straight, whereas it is medially prolonged and apically rounded or nearly pointed in all other Neolarrini . Besides these features, we report seven diagnostic characters for the genus Schwarzia , nearly half of which stem from the terminal segments of the female metasoma ( Fig. 2 ).

Figures

Fig. 1. Fossil-calibrated chronogram of Neolarrini in the new sense (including Biastes, Neolarra, Rhopalolemma, Townsendiella and Schwarzia) based on 773 ultraconserved elements. Pie charts show possible ancestral ranges. Individual slices are scaled according to their probability as calculated through BioGeoBEARS. Bootstrap support (BS) values and posterior probabilities are omitted but correspond to 100 and 1.0 for all nodes, except for the branching of Oreopasites which has a lower BS value.Asterisks (*) indicate newly described species.Stem and crown ages of host taxa along the timeline on the left are taken from Cardinal et al. (2018). Scale bars next to specimen photographs indicate 2 mm length.

Fig. 2. Summary of phylogenetic relationships of Neolarrini with all described species, except for Neolarra. Solid lines show relationships estimated with molecular data and placements with dashed lines are derived from morphology or taxonomic information. Mapped diagnostic characters are listed in Table 3. Larval morphological characters are indicated by a gray background. Information on bee and floral hosts is taken from various sources (Michener 1936,Torchio et al. 1967, Krombein et al. 1979, Warncke 1981, Warncke 1982, Janzon and Svensson 1984, Westrich 1990, Rozen and McGinley 1991, Rozen et al. 1997, Bogusch 2003, Proshchalykin and Lelej 2004, Rozen et al. 2009, Orr and Griswold 2015, Scheuchl and Willner 2016, Westrich 2018). The higher classification of plants follows the APG IV system (The Angiosperm Phylogeny group 2016). Warncke (1982) also lists Systropha curvicornis and S. planidens as hosts of Biastes emarginatus but the source for this information is unclear and has been doubted by other authors (Westrich 2018). No host information is available for Schwarzia and species for which boxes are gray.Asterisks (*) indicate newly described species.