Phylogenetic relationships of the bacchine flower flies (Diptera: Syrphidae) based on molecular characters, with a description of a new species of Melanostoma (Schiner, 1860)

Abstract

The phylogenetic relationships among the genera of the tribe Bacchini sensu lato (i.e., Syrphinae with simple, unsegmented aedeagus) were inferred using molecular evidence. The mitochondrial protein-coding gene cytochrome c oxidase subunit I (COI) and the nuclear ribosomal 28S and 18S rRNA genes for 54 bacchine taxa were analyzed using Bayesian inference and Maximum Likelihood. Among the analyzed taxa there is a new species of Melanostoma (Schiner) from Cameroon, Melanostoma janeceki Mengual, sp. nov., which is described in full. This new species has a complete metasternum without excavation, a characteristic that is not present in other species of Melanostoma, usually with an excavated metasternum, but it is the diagnostic character of the genus Afrostoma Skevington, Thompson & Vockeroth. Based on the phylogenetic placement of Melanostoma janeceki Mengual, sp. nov. the taxonomic status of Afrostoma as a genus is discussed and a new generic classification of Bacchini stat. rev. and Melanostomini stat. rev. is presented in the light of the inferred phylogeny. Results did not recover Bacchini sensu lato monophyletic, but into two groups as follows: Melanostoma and related genera, and Baccha, Platycheirus and related genera. Pseudoplatychirus van Doesburg is considered junior synonym of Platycheirus Le Peletier & Audinet-Serville, and Afrostoma Skevington, Thompson & Vockeroth as junior synonym of Melanostoma. Pyrophaena Schiner and Eocheilosia Hull comb. nov. are ranked as valid genera, and consequently, the genus Platycheirus is divided into four subgenera: Platycheirus (Carposcalis) (Enderlein), Platycheirus (Pachysphyria) (Enderlein), Platycheirus (Platycheirus), and Platycheirus (Tuberculanostoma) (Fluke) comb. nov.

Systematics and evolution of predatory flower flies (Diptera: Syrphidae) based on exon‐capture sequencing

“…We assume that these exceptions (with significant low support) to the general result of Baccha as sister to all other bacchines may be due to the reduced data sets and that the complete data set (1302 loci) is needed to recover this placement. We have recovered slightly different relationships among the other bacchines compared to Mengual (2020), with Pyrophaena Schiner being sister to ( Rohdendorfia Smirnov + ( Spazigaster Rondani + Syrphocheilosia Stackelberg)) with all branches having a nonparametric bootstrap value of 100 (Figure 2). No species of Eocheilosia Hull was available for the present study.…”

“…The four taxa were resolved together, including Asarkina biroi Bezzi with its black face (an earlier diagnostic character of the tribes Bacchini and Melanostomini). Published phylogenies using a small number of molecular markers obtained with Sanger sequencing always recovered Salpingogaster as sister to at least one member of the Ocyptamus and/or Sphaerophoria lineages when Asarkina was not sampled in those studies (Mengual, 2020; Mengual et al, 2015; Mengual, Ståhls, et al, 2018; Moran et al, 2022); conversely, Asarkina was always recovered as sister to the clade comprising Meliscaeva , Episyrphus and Asiobaccha when no Salpingogaster species was included in the survey (Mengual et al, 2008a, 2008b). Nevertheless, other previously inferred phylogenies that sampled both genera placed Asarkina as sister to the cluster with Meliscaeva , Episyrphus and Asiobaccha , and at the same time, placed Sapingogaster near the Ocyptamus and Sphaerophoria lineages (Mengual, 2015; Mengual et al, 2021).…”

The first species of Trichopsomyia Williston, 1888 (Diptera: Syrphidae) described from the Oriental region, with a discussion on the character states of the pilosity of the katepisternum

“…The development of the metasternum is the key character used in differentiating between Melanostoma Schiner, 1860 on the one hand, and Platycheirus Lepeletier & Serville, 1828 (Andersson 1970) and Afrostoma Skevington, Thompson & Vockeroth, 2014(Thompson & Skevington 2014) on the other. The development of the metasternum as a key character in differentiating Afrostoma from Melanostoma was recently rejected by Mengual (2019) who synonymized these two genera. The extent and length of the pilosity were used to separate several genera of XylotinI Williston, 1886(Hippa 1978, but also to separate Eupeodes (Lapposyrphus) lapponicus (Zetterstedt, 1838) from all other species of Eupeodes Osten Sacken, 1877 (Dušek & Láska 1967).…”

Eighteen mitochondrial genomes of Syrphidae (Insecta: Diptera: Brachycera) with a phylogenetic analysis of Muscomorpha

“…The most well-known is the three-subfamily system comprised of Syrphinae, Eristalinae, and Microdontinae [ 1 , 53 , 57 ]. Some studies combining morphological and genomic data suggest the Syrphinae tribe Pipizini should be elevated to its own subfamily, Pipizinae [ 12 , 48 , 51 , 58 ]. Most previous studies agreed that Syrphinae, Pipizinae/Pipizini, and Microdontinae are monophyletic, while the monophyly of Eristalinae is debated [ 8 , 9 , 48 , 57 ].…”