Niphargus aquilex Schiödte, 1855

Fišer, Cene, Zagmajster, Maja & Dethier, Michel, 2018, Overview of Niphargidae (Crustacea: Amphipoda) in Belgium: distribution, taxonomic notes and conservation issues, Zootaxa 4387 (1), pp. 47-74 : 50-51

Niphargus aquilex Schiödte, 1855

Published records: L.1—Gent, well in Botanic garden ( Schellenberg 1933, Leruth 1934a, 1934b, 1939b, Hubart & Dethier 1999); L.4—Sars-La-Bruyere pool (ZMB Berlin); L.7—Lessines, well ( Schellenberg 1933, Leruth 1934b, 1939b, Hubart & Dethier 1999); L.13—Grotte de Han (Hubart & Dethier 1999); L.16—Wavreille, well 400 m west (Fišer et al. 2017); L.25—Pré-au-Tonneau cave ( Leruth 1934a, 1934b, 1939b, Hubart & Dethier 1999, ZMB Berlin); L.26—Rochefort cave ( Schellenberg 1933, Leruth 1934b, 1939b, Hubart & Dethier 1999); L.75—Pouhon des Cuves, in gravel ( Leruth 1939b, Hubart & Dethier 1999); L.76—Bévercé La Varchette, gravel of brook bank (ZMB Berlin); L.84—Remouchamps cave ( Leruth 1934a, 1934b, 1939b, Hubart & Dethier 1999, ZMB Berlin); L.91—La Reid, brooks and springs ( Pandourski & Dethier 2006); L.112—Sainte Anne cave ( Leruth 1934a, 1934b, 1939b, Hubert & Dethier 1999, ZMB Berlin); L.117—Grotte de Flère (Hubart & Dethier 1999); L.121—Trou du Diable cave ( Leruth 1934b, 1939b, Hubart & Dethier 1999); L.127—Végétations cave ( Leruth 1934b, 1939b, Hubart & Dethier 1999, Dethier & Hubart 2010, ZMB Berlin); L.136—Grotte de Bebronne (Hubart & Dethier 1999); L.139—House well in Beyne-Heusay (ZMB Berlin); L.143—Herstal, wells ( Leruth 1939b, Hubart & Dethier 1999); L.146—Spring S.1 of La Xhavée ( Leruth 1939b, Hubart & Dethier 1999); L.152—Gravel of Meuse river, phreatic ( Leruth 1939b); L.153—Hermalle sous Argenteau, pump well (Hubart & Dethier 1999, ZMB Berlin); L.167—Bohon cave ( Leruth 1939b, Hubart & Dethier 1999).

New records: L.27—Fayt cave (2.12.2000, GR); L.34—Netinne cave (31.3.2001, MD); L.93—La Reid, brooks and springs, station B1 (18.3.2002, MD); L.110—Ru de Targnon, brook (6.11.2002, MD, JMH).

Niphargus aquilex is small to mid-sized species, distinct by its slender body, and often misidentified with similar species like N. tauri Schellenberg 1940 (see Karaman 1973). The species was originally described from British Isles ( Karaman 1980). It is one of the most frequently reported Niphargus species from the entire Europe, including Austria ( Straškraba 1958), Belgium ( Straškraba 1958), Czech ( Schellenberg 1938; Skalski 1972); France ( Straškraba 1958), Germany ( Ronneberger 1975; Zaenker & Nagel 1999), Luxembourg ( Straškraba 1958), Italy ( Karaman 1982), Netherlands ( Holthuis 1950; Stock 1961; Cuppen 1978a,b), and Poland ( Skalski 1970). The species is known from 26 localities in Belgium, four of which we report here for the first time ( Fig. 2 ). Most of the localities are situated in south-eastern Belgium, but there are three localities in its western parts ( Fig. 2 ), referring to localities from wells (App. 1). We collected the species mainly in tiny pools in mud and clay and might have been washed out from epikarst. Other published records from Belgium report the species also from interstitial and wells. This is in accord with published information, hypothesizing that species with such morphologies are bound to tiny crevices, either in interstitial or in epikarst ( Trontelj et al. 2012).

Many populations of this species were described as distinct subspecies (e.g., Sket 1999); however, recent molecular analyses indicated that this morphology evolved several times independently ( Trontelj et al. 2009). The populations from Belgium likely belong to species complex distributed between southern Britain and Germany (possibly “ N. aquilex E” from McInnerney et al. 2014). Although N. aquilex from West Europe was included into at least three molecular studies ( Trontelj et al. 2009; Hartke et al. 2011; McInnerney et al. 2014), its taxonomic structure so far remains unclear. All molecular studies hint extremely complex taxonomy that ought to be revised in a separate study.

Figures

FIGURE 2. Distribution of M. leruthi (left) and N. aquilex (right) in Belgium. Blue circles refer to data from published sources, while red circles refer to new records published for the first time in this study.