An updated tribal classification of Lamiaceae based on plastome phylogenomics

Background A robust molecular phylogeny is fundamental for developing a stable classification and providing a solid framework to understand patterns of diversification, historical biogeography, and character evolution. As the sixth largest angiosperm family, Lamiaceae, or the mint family, consitutes a major source of aromatic oil, wood, ornamentals, and culinary and medicinal herbs, making it an exceptionally important group ecologically, ethnobotanically, and floristically. The lack of a reliable phylogenetic framework for this family has thus far hindered broad-scale biogeographic studies and our comprehension of diversification. Although significant progress has been made towards clarifying Lamiaceae relationships during the past three decades, the resolution of a phylogenetic backbone at the tribal level has remained one of the greatest challenges due to limited availability of genetic data. Results We performed phylogenetic analyses of Lamiaceae to infer relationships at the tribal level using 79 protein-coding plastid genes from 175 accessions representing 170 taxa, 79 genera, and all 12 subfamilies. Both maximum likelihood and Bayesian analyses yielded a more robust phylogenetic hypothesis relative to previous studies and supported the monophyly of all 12 subfamilies, and a classification for 22 tribes, three of which are newly recognized in this study. As a consequence, we propose an updated phylogenetically informed tribal classification for Lamiaceae that is supplemented with a detailed summary of taxonomic history, generic and species diversity, morphology, synapomorphies, and distribution for each subfamily and tribe. Conclusions Increased taxon sampling conjoined with phylogenetic analyses based on plastome sequences has provided robust support at both deep and shallow nodes and offers new insights into the phylogenetic relationships among tribes and subfamilies of Lamiaceae. This robust phylogenetic backbone of Lamiaceae will serve as a framework for future studies on mint classification, biogeography, character evolution, and diversification. Graphical abstract

On the tribal classification of the Nearctic Melolonthinae (Coleoptera: Scarabaeidae), with descriptions of new species of Acoma Casey, 1889

The subfamily Melolonthinae (Coleoptera: Scarabaeidae) is defined and characterized, and a brief summary of the world melolonthine tribes and their distributions are provided. Nearctic genera previously considered incertae sedis (Acoma Casey, 1889, Chaunocolus Saylor, 1937 and Chnaunanthus Burmeister, 1844, Phobetus LeConte, 1856, and Warwickia Smith & Evans, 2005) are each placed in the proposed new tribes Acomini, Chnaunanthini, Phobetusini, and Warwickiini, respectively. Tribal assignments for all Nearctic melolonthine genera are presented. Acoma chihuahuaensis, A. eusexfoliata, A. nonglabrata, and A. pararobusta are all new species described from Mexico. The only known example of a female Acoma, represented by a specimen of A. knulli Howden, 1958, is figured and characterized. The generic composition of the Nearctic Melolonthini and Rhizotrogini is examined. Madiniella Chalumeau & Gruner, 1976, previously placed in Tanyproctini, is transferred to Rhizotrogini. The subfamilies Oncerinae and Podolasiinae are each removed as tribes from the Melolonthinae and elevated to the subfamily level within Scarabaeidae. The subtribe Triodonina is placed in synonymy with the tribe Rhizotrogini. An updated generic checklist and tribal key of the Nearctic Melolonthinae are provided.

Molecular Phylogeny and Tribal Classification of Flanged Bombardier Beetles (Carabidae: Paussinae)

Members of the carabid subfamily Paussinae are known for their explosive defensive chemistry and their associations with ants, which vary from some species being facultative predators of adult ants to others being obligate predators of ant brood. This association with ants has driven extreme morphological adaptations in some lineages. Approximately 750 species are currently classified into four tribes: Metriini, Ozaenini, Protopaussini and Paussini. Here we use molecular sequence data from five genes (28S ribosomal DNA; 18S ribosomal DNA; wingless; carbamoyl phosphate synthetase domain of the rudimentary gene; and arginine kinase) to reveal patterns of deep divergence and provide a new tribal level classification reflecting evolutionary history. We recognize and describe two new tribes, and the tribe Ozaenini is redefined. Among other traits, members of each tribe has a characteristic shape of the cuticular fold at the posterolateral angle of both elytra, known as the flange of Coanda.

Defining new dung beetle tribes to resolve discrepancies between phylogeny and tribal classification in the subfamily Scarabaeinae (Coleoptera: Scarabaeidae)

The monophyletic, dung beetle subfamily, Scarabaeinae, has a long history of subdivision into tribes and subtribes represented by groups of genera unified by designated characters. Various tribal names have been proposed although only 11 or 12 were considered valid in recent reviews. Three of these 12 tribes have now been invalidated due to extensive polyphyly indicated by both morphological and molecular phylogenies. Although partial revision of tribal classification was proposed in the most recent global molecular phylogeny of the subfamily, this was primarily limited to redefinition of membership or provision of support for pre-existing tribes. Complete revision was not attempted as the phylogeny examined interrelationships between only ~52% of the valid described genera. It was also hampered by inconsistencies in topology using different analytical methods, weakened by limited bootstrap support for many basal nodes, as well predicting several phylogenetic relationships that seemed anomalous with regards to biogeographical hypotheses. Nevertheless, using this phylogeny, we propose further revision of tribal classification in a clade of primarily African genera included within a group defined as “basal Scarabaeinae”. Using three different methods, the sister lineages of this clade were consistently recovered, mostly with strong bootstrap support for their molecular relatedness. Therefore, we provide a number of defining morphological characters to support their proposed designation as three new tribes: Byrrhidiini, Endroedyolini and Odontolomini. We also discuss approaches to a full tribal revision as well as the implications for historical biogeography of the Scarabaeinae.