Alexandrella Chevreux 1911
- Dataset
- Epimeria of the Southern Ocean with notes on their relatives (Crustacea, Amphipoda, Eusiroidea)
- Rank
- GENUS
Classification
- kingdom
- Animalia
- phylum
- Arthropoda
- class
- Malacostraca
- order
- Amphipoda
- family
- Stilipedidae
- genus
- Alexandrella
discussion
Remarks We decided to include the description of a new Alexandrella species herein because this genus belong to the same large clade as Epimeria (Verheye et al. 2016 b, 2017) and because the new species is large, very characteristic and was already mentioned and illustrated in the cruise report of ANT-XXIX / 3 (d’Udekem d’Acoz & Verheye 2013). Moreover, we felt that a quick overview of Alexandrella taxonomy would be a good test for checking whether the underestimated biodiversity found in Epimeria was unique for large Antarctic amphipods or representative of a general situation. This led us to draw a dire conclusion, that the taxonomy of Antarctic Alexandrella is even messier than for Epimeria before our present revision, and a significant number of undescribed species obviously occur in the Southern Ocean. The uniform morphology of Alexandrella species simply contributed to mask its true taxonomic diversity and to promote the convenient but spurious concept of ‘ variable widespread species’. The morphological differences between the genera Alexandrella and Bathypanoploea as proposed by Holman & Watling (1983) are ill-defined (Berge & Vader 2005 b, 2005 c) and genetic data (Verheye et al. 2016 b) confirm that Bathypanoploea pulchra (as A. schellenbergi) and Alexandrella cf. mixta (as A. aff. dentata) are very close relatives. The two genera are therefore considered herein as synonyms. Besides the species from the temperate and polar parts of the southern hemisphere treated herein, Alexandrella includes an Atlantic abyssal species: A. setosa Serejo, 2014 (see Serejo 2014) and two abyssal species from the North Pacific: Alexandrella carinata (Birstein & Vinogradova, 1960) and a second, undescribed species examined by the first author. The species described and illustrated as Astyroides carinatus by Birstein & Vinogradova (1960) exhibits almost all the characters of Alexandrella. J. L. Barnard (1969) considered Astyroides as a junior synonym of Alexandrella, and it is only reluctantly that Holman & Watling (1983) accepted Astyroides as valid. In the reprint of Birstein & Vinogradova (1960) available to us, there is a handwritten comment by Vinogradova relegating Astyroides into the synonymy of Alexandrella. This synonymization is formally adopted herein.
etymology
Etymology The name Alexandrella presumably refers to Alexander Island, where the type species of the genus was collected.