Archipelago-Wide Patterns of Colonization and Speciation Among an Endemic Radiation of Galápagos Land Snails.

Newly arrived species on young or remote islands are likely to encounter less predation and competition than source populations on continental landmasses. The associated ecological release might facilitate divergence and speciation as colonizing lineages fill previously unoccupied niche space. Characterizing the sequence and timing of colonization on islands represents the first step in determining the relative contributions of geographical isolation and ecological factors in lineage diversification. Herein, we use genome-scale data to estimate timing of colonization in Naesiotus snails to the Galápagos islands from mainland South America. We test inter-island patterns of colonization and within-island radiations to understand their contribution to community assembly. Partly contradicting previously published topologies, phylogenetic reconstructions suggest that most Naesiotus species form island-specific clades, with within-island speciation dominating cladogenesis. Galápagos Naesiotus also adhere to the island progression rule, with colonization proceeding from old to young islands and within-island diversification occurring earlier on older islands. Our work provides a framework for evaluating the contribution of colonization and in situ speciation to the diversity of other Galápagos lineages.

World of Crayfish™: a web platform towards real-time global mapping of freshwater crayfish and their pathogens.

Freshwater crayfish are amongst the largest macroinvertebrates and play a keystone role in the ecosystems they occupy. Understanding the global distribution of these animals is often hindered due to a paucity of distributional data. Additionally, non-native crayfish introductions are becoming more frequent, which can cause severe environmental and economic impacts. Management decisions related to crayfish and their habitats require accurate, up-to-date distribution data and mapping tools. Such data are currently patchily distributed with limited accessibility and are rarely up-to-date. To address these challenges, we developed a versatile e-portal to host distributional data of freshwater crayfish and their pathogens (using Aphanomyces astaci, the causative agent of the crayfish plague, as the most prominent example). Populated with expert data and operating in near real-time, World of Crayfish™ is a living, publicly available database providing worldwide distributional data sourced by experts in the field. The database offers open access to the data through specialized standard geospatial services (Web Map Service, Web Feature Service) enabling users to view, embed, and download customizable outputs for various applications. The platform is designed to support technical enhancements in the future, with the potential to eventually incorporate various additional features. This tool serves as a step forward towards a modern era of conservation planning and management of freshwater biodiversity.

A new species of stygobitic snail in the genus Antrorbis Hershler & Thompson, 1990 (Gastropoda, Cochliopidae) from the Appalachian Valley and Ridge of eastern Tennessee, USA.

A new species of cave snail (Littorinimorpha: Cochliopidae) in the genus Antrorbis is described from the dark zone of two caves in the Appalachian Valley and Ridge province in eastern Tennessee, United States. The Tennessee Cavesnail, Antrorbis tennesseensis Perez, Shoobs, Gladstone, & Niemiller, sp. nov. is distinguished from its only known congener, Antrorbis breweri, by the absence of raised tubercles on its finely spirally striate protoconch, and its unique radular formula. Moreover, A. tennesseensis is genetically distinct from A. breweri based on substantial divergence at the mitochondrial CO1 locus. This is the first cavesnail to be described from the Appalachian Valley and Ridge (AVR) physiographic province in the state of Tennessee, which previously represented a substantial gap in the distribution of stygobitic (i.e., aquatic, subterranean-obligate) gastropods.

Occurrence of the large ostracod, Chlamydotheca unispinosa (Baird, 1862), in temporary waters of Montserrat, Lesser Antilles.

Four populations of the large freshwater ostracod, Chlamydotheca unispinosa (Baird, 1862), were discovered on the Caribbean island of Montserrat. These are the first records of the species on Montserrat and extend its known distribution approximately 113 km northwest and 63 km southeast of the closest known populations on Îles des Saintes (Guadeloupe) and Nevis, respectively. We provide the first DNA barcode for C. unispinosa, a 686 bp fragment of the COI gene which may be used for future comparative studies of this widely distributed species.

A new record of the freshwater polychaete Namanereis hummelincki (Polychaeta: Nereididae) from epigean waters of Montserrat.

The presence of the freshwater polychaete, Namanereis hummelincki (Augener), on Montserrat is documented for the first time. Although collected in the sediment of a freshwater stream, this subterranean species most likely lives in groundwater aquifers. A mitochondrial cytochrome c oxidase subunit I (COI) sequence obtained from this material supports assignment to the genus Namanereis Chamberlin, and morphological analysis supports identification as N. hummelincki. Differences in jaw morphology observed in the Montserrat specimens may indicate long-term separation from other Caribbean island populations.