Phylogeny of the most species-rich freshwater bivalve family (Bivalvia: Unionida: Unionidae): Defining modern subfamilies and tribes

Abstract

a b s t r a c t Freshwater mussels of the order Unionida are key elements of freshwater habitats and are responsible for important ecological functions and services. Unfortunately, these bivalves are among the most threatened freshwater taxa in the world. However, conservation planning and management are hindered by taxonomic problems and a lack of detailed ecological data. This highlights the urgent need for advances in the areas of systematics and evolutionary relationships within the Unionida. This study presents the most comprehensive phylogeny to date of the larger Unionida family, i.e., the Unionidae. The phylogeny is based on a combined dataset of 1032 bp (COI + 28S) of 70 species in 46 genera, with 7 of this genera being sequenced for the first time. The resulting phylogeny divided the Unionidae into 6 supported subfamilies and 18 tribes, three of which are here named for the first time (i.e., Chamberlainiini nomen novum, Cristariini nomen novum and Lanceolariini nomen novum). Molecular analyses were complemented by investigations of selected morphological, anatomical and behavioral characters used in traditional phylogenetic studies. No single morphological, anatomical or behavioral character was diagnostic at the subfamily level and few were useful at the tribe level. However, within subfamilies, many tribes can be recognized based on a subset of these characters. The geographical distribution of each of the subfamilies and tribes is also presented. The present study provides important advances in the systematics of these extraordinary taxa with implications for future ecological and conservation studies.

Molecular phylogeny of the Nearctic and Mesoamerican freshwater mussel genus Megalonaias

“…Although the higher-level classification of the Unionidae is unstable (Whelan et al, 2011;Pfeiffer & Graf, 2015;Lopes-Lima et al, 2016;Bolotov et al, 2017), it remains clear that the subfamily Ambleminae has experienced the most dramatic evolutionary radiation, representing over half of the species-level diversity of the family. The Ambleminae is distributed across much of North America, occupying most permanent freshwater habitats east of the Continental Divide of the Americas, from northern Canada south to the Isthmus of Panama.…”

Conservation of freshwater bivalves at the global scale: diversity, threats and research needs

“…Many species of FB are still poorly understood, especially in Central America, Southeast Asia and Sundaland (Lopes-Lima et al, 2014, 2017b. This lack of knowledge hampers their status assessment.…”

“…Pereira et al, 2014for South America, Walker et al, 2014Lopes-Lima et al, 2017a for Europe;Williams et al, 2017 for North America, andZieritz et al, 2017 for East and Southeast Asia). Additionally, intercontinental cooperative research is also becoming increasingly common (see for example Zieritz et al, 2016;Lopes-Lima et al, 2017b). In order to discuss the current and future research challenges and needs, the Second International Meeting on Biology and Conservation of Freshwater Bivalves was hosted by the Great Lakes Centre at SUNY Buffalo State College in Buffalo, New York, USA, from 4 to 8 October 2015, bringing together over 80 scientists from 19 countries and four continents (Europe, North America, South America and Australia) .…”

Lifting the curtain on the freshwater mussel diversity of the Italian Peninsula and Croatian Adriatic coast

“…Morphological identification is notoriously difficult in almost all Unionida because of the high morphological variability within species and morphological convergences between species, but the problem is particularly common in Anodontinae, which lack diagnostic teeth (e.g. Zieritz et al 2010;Lopes-Lima et al 2017a). As a result, Haas (1969), for example, incorrectly lumped all the European Anodonta species-including all Italian and Dalmatian types-under a single species, A. cygnea.…”