Cryptic taxonomic diversity and high-latitude melanism in the glossiphoniid leech assemblage from the Eurasian Arctic.

The family Glossiphoniidae is a diverse and widespread clade of freshwater leeches, playing a significant role in functioning of aquatic ecosystems. The taxonomy and biogeography of leeches from temperate, subtropical, and tropical regions attracted much attention of zoologists, while their taxonomic richness and distribution in the Arctic are poorly understood. Here, we present an overview of the Eurasian Arctic Glossiphoniidae based on the most comprehensive occurrence and DNA sequence datasets sampled to date.

Is the South African leech Barbronia gwalagwalensis Westergren amp; Siddall, 2004 (Hirudinida: Erpobdelliformes: Salifidae) a Paleotropical species?

The freshwater leech family Salifidae Johansson has a Paleotropical range, with a hotspot of species richness in the Oriental Region, and a few species endemic to Africa, Madagascar, and Reunion. Barbronia gwalagwalensis Westergren Siddall, 2004 was thought to be a characteristic example of the latter group being a lineage endemic to South Africa. However, we found that this species also occurs in Asia (Myanmar and Korea).

First freshwater mussel-associated piscicolid leech from East Asia.

Parasites and symbionts of freshwater mussels are poorly understood, although a diverse assemblage of mussel-associated leeches (Glossiphoniidae) was recently described. Here, we report on the discovery of a fish leech (Piscicolidae) in the mantle cavity of the freshwater mussel Cristaria plicata (Unionidae) in the Russian Far East. It is the first member of this leech family being associated with freshwater molluscs.

Freshwater mussels house a diverse mussel-associated leech assemblage.

Freshwater mussels (Unionida) are one of the most imperiled animal groups worldwide, revealing the fastest rates of extinction. Habitat degradation, river pollution and climate change are the primary causes of global decline. However, biological threats for freshwater mussels are still poorly known.

An example of a possible leech-bryozoan association in freshwater.

Associations of various invertebrate species with bryozoans and sponges are a well-known marine phenomenon but such epizooic communities are far less diverse in freshwater environments. Here an occurrence of numerous leeches Alboglossiphoniacf.papillosa (Braun, 1805), in interstitial spaces between zooids of a colony of the freshwater bryozoan species Plumatellaaff.