On the molecular and morphological evolution of continental and insular Cryptorchestia species, with an additional description of C.garbinii (Talitridae).

Domenico Davolos,Ronald Vonk,Marco Tarocco,Leonardo Latella,Elvira De Matthaeis,Murat Özbek

doi:10.3897/zookeys.783.26179

Domenico Davolos, Ronald Vonk + Show 4 more

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https://doi.org/10.3897/zookeys.783.26179

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Abstract

Semi-terrestrial talitrid amphipods of the genus Cryptorchestia (sensu Lowry and Fanini 2013) associated with freshwater-soaked leaf litter were known to occur in inland lakes of Turkey and at the shores of the Black Sea. Before 2013 they had been reported as Orchestiacavimana and later as Cryptorchestiacavimana. In our phylogenetic tree, inferred from a mitochondrial and nuclear gene dataset (cytochrome oxidase I (COI), and histone H3 (H3), respectively), we show that these Turkish populations belong to Cryptochestiagarbinii, a common and widespread continental species, which is closely related to C.cavimana (endemic to Cyprus) and C.ruffoi (endemic to Rhodes). For the Turkish and European populations of C.garbinii, we found low levels of both genetic differentiation and morphological variation, and an age-related size variability (increasing at each moult) of the small lobe in the male gnathopod I merus, the main taxonomically diagnostic character for Cryptorchestia. A mainland (C.garbinii) versus insular isolation and in situ speciation (C.cavimana, and C.ruffoi) in the two east Mediterranean islands of Cyprus and Rhodes is discussed in relation to terrestrial Cryptorchestia species endemic to North East Atlantic volcanic islands (Azores, Canary Islands, and Madeira). The incorporation of five Mediterranean and Atlantic Orchestia species in the Bayesian analysis of the two genes (COI, and H3) indicated that both genera Orchestia and Cryptorchestia are not monophyletic.

Highlights

The genus Cryptorchestia Lowry & Fanini, 2013 was erected to accommodate semi-terrestrial and terrestrial species, associated with freshwater, set apart from the marine, supralittoral beachhoppers in the genus Orchestia Leach, 1814
Before 2013 they had been reported as Orchestia cavimana Heller, 1865 and after that as Cryptorchestia cavimana (Heller, 1865), without considering that C. cavimana is endemic to Cyprus (Ruffo et al 2014, Davolos et al 2017)
Our phylogenetic analysis recovered a monophyletic clade (PP = 0.99) that was formed by the continental species C. garbinii, widely distributed from Turkey to central Europe, and two other freshwater Cryptorchestia species, C. cavimana, and C. ruffoi, which are endemic to the east Mediterranean islands of Cyprus and Rhodes, respectively

Summary

Introduction

The genus Cryptorchestia Lowry & Fanini, 2013 was erected to accommodate semi-terrestrial and terrestrial species, associated with freshwater, set apart from the marine, supralittoral beachhoppers in the genus Orchestia Leach, 1814. Up to this date, Cryptorchestia contains eleven species (Horton et al 2018) and is mainly distributed over several North East Atlantic islands (Azores, Canary Islands, Madeira), Europe, and over the Eastern Mediterranean, including the islands of Rhodes and Cyprus (Davolos et al 2017). Özbek et al (2004) listed the Malacostraca species of the Iznik and Uluabat lakes and recorded O. cavimana (here identified as C. garbinii Ruffo, Tarocco and Latella, 2014) from those lakes. Özbek et al (2017) reported C. cavimana (probably C. garbinii, see below) from a creek near Silivri, a town bordering the northern coast of the Sea of Marmara

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