Niphargus pachypus Schellenberg, 1933

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 : 53

Niphargus pachypus Schellenberg, 1933

Published records: L.112—Sainte Anne cave ( Leruth 1934a, 1934b, 1939b, Delhez et al. 1999, Hubart & Dethier 1999, ZMB Berlin); L.132—Trou des Sottais cave ( Leruth 1939b, Hubart & Dethier 1999); L.146— Spring S.1 of La Xhavée ( Leruth 1939b, Hubart & Dethier 1999); L.149—Ouffet, Spring S.1 ( Leruth 1939b); L.152—Gravel of Meuse river, phreatic ( Leruth 1939b); L.153—Hermalle sous Argenteau, pump well (Hubart & Dethier 1999); L.157—Waha springs ( Leruth 1939b, ZMB Berlin); L.169—Nys cave ( Leruth 1939b, ZMB Berlin).

New records: L.110—Ru de Targnon, brook (23.8.2000, MD; 6.11.2002, MD & JMH); L.113—Spring close to Monceau cave (04.06.2001, MD & JMH; 06- 12.06.2002, MD); L.123—Blanc Gravier, brook, G2 station (29.4.2003, MD); L.141—Petites Soeurs des Pauvres, draining gallery (23.3.2002, MD & JMH; 5.12.2003, MD & JMH); L.148—Rhieux, underground brook (23.3.2006, MD & JMH); L.150—Argenteau, draining gallery (15.6.2006, MD).

The species was described as N. kochianus pachypus from France ( Schellenberg 1933). The taxon is distributed in France, Belgium, Luxembourg and Netherlands ( Stock & Gledhill 1977). In Belgium, it is restricted to karst areas, where it was collected along rivers. In newly collected material we found the species only in the localities around Liège in Eastern part of the country ( Fig.4 ). We collected the species mainly in springs, but also caves (often in “gours” — little pools in the calcite reservoirs; see the list, App. 1). The species seems to be generally bound to small pore habitats ( Stock & Gledhill 1977).

Already Stock & Gledhill (1977) erected N. k. pachypus from subspecies to species level, and subsequent molecular analyses suggest that the species is not related to N. kochianus s. str. (McInnerney et al. 2014). Unlike previous species, this species shows relatedness towards niphargids from continental Europe. Phylogeography and population structure of this species was never studied, but indirect evidence from N. virei and N. schellenbergi , derived from similar distributional patterns (see below), suggests that some phylogeographic structure and perhaps cryptic species cannot be ruled out.

Figures

FIGURE 4. Distribution of N.pachypus (left) and N.puteanus (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.