Australian Tropical Marine Micromolluscs: An Overwhelming Bias

Abstract

Abstract:Assessing the marine biodiversity of the tropics can be overwhelming, especially for the Mollusca, one of the largest marine phyla in the sea. With a diversity that can exceed macrofaunal richness in many groups, the micro/meiofaunal component is one of most overlooked biotas in surveys due to the time-consuming nature of collecting, sorting, and identifying this assemblage. We review trends in micromollusc research highlighting the Australian perspective that reveals a dwindling taxonomic effort through time and discuss pervasive obstacles of relevance to the taxonomy of micromolluscs globally. Since a high during the 1970s, followed by a smaller peak in 2000, in 2010 we observe a low in micromolluscan collection activity in Australia not seen since the 1930s. Although challenging, considered planning at each step of the species identification pathway can reduce barriers to micromolluscan research (e.g., role of types, dedicated sampling, integration of microscopy and genetic methods). We discuss new initiatives to trial these methods in Western Australia, an understudied region with high biodiversity, and highlight why micromolluscs are worth the effort. A number of important fields that would benefit from increased focus on this group (e.g., ecological gaps) are considered. The methods and strategies for resolving systematic problems in micromolluscan taxonomy are available, only the desire and support to reverse the decline in knowledge remains to be found.

Natural history clues to the evolution of bivalved gastropods (Mollusca: Gastropoda: Sacoglossa: Juliidae)

“…There is, thus, some modest diversity in the family. Over the history of work on this clade, the largest number of species were found first in Australia and Japan, and the lack of records in other regions with suitable habitat certainly reflects lower sampling effort (Middelfart et al 2016). At the two study sites examined here, B. singaporensis is the only shelled sacoglossan that is obligately feeding on and living on Caulerpa.…”

“…This point has been made repeatedly, about the underestimating of biodiversity in less-studied taxonomic groups and habitats (e.g. Middelfart et al 2016;Sigwart and Garbett 2018), as well as the downstream cascading problems that arise from analyses based on poor taxonomic resolution and accuracy (Bortolus 2008). Understanding the natural history of marine species in SE Asia is critical to broader scientific aspirations of assessing Earth's species richness, evolutionary innovations, and the drivers and limits of diversity and diversification.…”

Diferencias morfométricas de dos especies del género Eatoniella en Isla Navarino, Reserva de Biosfera Cabo de Hornos, Chile

“…Probablemente existe un gran porcentaje de taxa que aún no han sido descritas o que aún conservan caracteres diagnósticos que no han sido estudiados (Geiger et al 2007). Por ello, es relevante la información descriptiva y más si es útil para diferenciar sus especies, considerando la importancia que tienen los micromoluscos, desde el punto de vista del conocimiento de la biodiversidad y taxonomía (Sasaki 2008, Middelfart et al 2016.…”

Erecting a new family forSpirostyliferina, a truncatelloidean microgastropod, and further insights into truncatelloidean phylogeny

“…. These superfamilies contain mostly micromolluscan taxa making them difficult to sort and identify and are consequently less studied (Middelfart, Kirkendale, & Wilson, 2016). Microgastropods vary in abundance and diversity across different habitats, with higher diversity reported at lower latitudes (e.g.…”

“…Microgastropods vary in abundance and diversity across different habitats, with higher diversity reported at lower latitudes (e.g. Barnes, 2010), but a lack of study of the Australian fauna limits our understanding of their role in ecosystems and their overall diversity (Middelfart et al, 2016;Olabarria & Chapman, 2001).…”