Niphargus aquilex Schiodte 1855

Niphargus aquilex Schiødte, 1855 Fig. 1 Remarks Weber et al. (2023) treated this species as N. aquilex B, which can be considered N. aquilex sensu stricto. The species was regularly found in nearly all types of biotopes, but surprisingly often in helocrene springs (Supp. file 4.1). It is widespread and common in Western Germany, with more scattered records in Luxembourg, Belgium, and along the Channel Coast in France and Great Britain (Fig. 1). A neotype locality was established by Karaman (1980) from Crowborough (United Kingdom) without mentioning precise coordinates. We sampled the region of Crowborough, and our specimens and sequences can therefore be considered to originate from the neotype locality. The drawing of Schiødte (1855) shows two of the characteristics of N. aquilex, that is, the single seta on the dactylus of the gnathopods and the rounded 3 rd epimeral plate. Karaman (1980) re-described N. aquilex in detail, but he did not take into consideration that N. aquilex might comprise a species complex of morphological similar (pseudocryptic) or identical (cryptic) taxa. Karaman’s specimens are now>40 years old, and we thus did not try to sequence them. Nevertheless, we obtained three freshly collected specimens from Crowborough and sequenced two COI and three 28S rDNA sequences. All the sequences corresponded to the former species B senus Weber et al. (2023), which was already delineated by McInerney et al. (2014).