Insights into the morphology and molecular characterisation of glacial relict Eurytemoralacustris (Poppe, 1887) (Crustacea, Copepoda, Calanoida, Temoridae).

Łukasz Sługocki,Lucyna Kirczuk,Anna Rymaszewska

doi:10.3897/zookeys.864.34259

Abstract

Eurytemoralacustris (Poppe, 1887) is a stenothermic glacial relict whose narrow environmental requirements make it an indicator species for good ecological conditions. The primary threats to this species are eutrophication and global warming. Many authors have described E.lacustris in taxonomic keys; however, its morphological description is unsatisfactory. Therefore, in this study, we aimed to review morphological characteristics of E.lacustris that were previously undescribed in the literature and to provide the molecular characteristics based on the two conservative mitochondrial genes: cytochrome c oxidase I (COI) and cytochrome b (cytb). The new record of E.lacustris indicates that it is a more widespread species than previously hypothesized. Width-to-length ratio of the last female endopod segment of legs indicates variation among the widely distributed species of the genus in Europe (i.e., E.lacustris, E.velox (Lilljeborg, 1853), and E.affinis (Poppe, 1880)). We also found variability of number of setae on the second segment of male endopod. Furthermore, our analysis confirms the occurrence of species in different than exclusively freshwater habitats.

Highlights

The marine, estuarine, and freshwater genus Eurytemora is represented in Europe by eight species (22 worldwide) (Błędzki and Rybak 2016)
Alekseev and Souissi (2011) described a new species, Eurytemora carolleeae, from the North American waters, which is invasive in European waters
Specimens of E. lacustris were obtained in September 2017 from Lake Cieszęcino (53°55'41.7"N, 16°49'29.6"E) (Fig. 1), north western Poland at an altitude of 154 m a.s.l

Summary

Introduction

The marine, estuarine, and freshwater genus Eurytemora is represented in Europe by eight species (22 worldwide) (Błędzki and Rybak 2016). Alekseev and Souissi (2011) described a new species, Eurytemora carolleeae, from the North American waters, which is invasive in European waters. Depending on the salinity of the water, Eurytemora shows highly evolvable traits (Lee 1999; Souissi et al 2016). Most studies on Eurytemora concerns estuarine clade Eurytemora affinis (Poppe, 1880), which presents adaptations to freshwater habitats. The large morphological plasticity of Eurytemora in relation to its habitat can lead to confusion regarding the identification of the species. In contrast to the widely distributed species such as E. affinis, in Europe, other species of the genus are present that represent relicts of Eurytemora on a global scale

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