Niphargus wasgauensis Weber & Brad, 2025

Niphargus wasgauensis Weber & Brad sp. nov.

urn:lsid:zoobank.org:act:

Figs 30–38 View Fig View Fig View Fig View Fig View Fig View Fig View Fig View Fig View Fig

Diagnosis

Medium-sized Niphargus species, poorly setose. Right postero-ventral angle of epimeral plates. 6 spines of maxilla I outer lobe with 1–3 teeth each; 1 spine with several smaller teeth. Mandibular palp with small number (1–2) of B setae. Gnathopods with 2 setae along outer margin of dactylopodite. Pereiopod VII, the longest leg, almost half of total body length. Pleopods retinaculum with 2–3 hooks. Uropod I, longer exopodite. Uropod II, longer endopodite. Uropod III sexually dimorphic, exopodite elongated in males. Telson with 5 apical spines on each lobe. The COI marker shows a single pure diagnostic site at position 586 (C). Two 28S rDNA alleles are diagnostic (with 1 heterozygous specimen) as well as 12 COI barcodes.

Etymology

The species name derives from the Wasgau uplands, which are formed by the Palatinate Forest ( Germany) in the North and the Vosges Mountains ( France) in the South. In Weber et al. (2023), this species was treated as N. aquilex I.

Material examined

Holotype

GERMANY • ♂; Rhineland-Palatinate, Sülzlochquelle 2 in the community of Godramstein ; rheocrene spring; 49.2152° N, 8.0842° E; 1 Jan. 2017; Dieter Weber leg.; kept intact in 96% ethanol; 170101-25; MNHNL130578 .

GoogleMaps

Paratypes

GERMANY • 1 ♂; same collection data as for holotype; 1 Jan. 2017; dissected and appendages drawn; 170101-22; ISER microscope slide DW170101-22 • 1 ♀; Rhineland-Palatinate, Breitenborntal-Brunnen 3 at Schweigen-Rechtenbach ; 49.0643° N, 7.9406° E; 16 Jul. 2016; Dieter Weber leg.; dissected and appendages drawn; 160716-25; ISER microscope slide DW160716-25 GoogleMaps .

GoogleMaps

Molecular data

COI and 28S rDNA sequences of specimens belonging to Niphargus wasgauensis sp. nov. were deposited in GenBank. COI and 28S rRNA accession numbers are present in Supp. file 6 and Supp. file 9, respectively.

Description (male paratype ISER DW 170101-22)

Measurements

Total body length is 6.22 mm ( Fig. 30 View Fig ).

Head

Head ( Fig. 30 View Fig ) 9.6% of total body length. Eyes and rostrum absent.

Antennae

Antenna I ( Fig. 31A View Fig ): with main flagellum formed of 20 articles, representing 52% of total body length. Peduncle length 36% of total length of antenna I. Accessory flagellum ( Fig. 31B View Fig ) biarticulated; proximal article shorter than first article of main flagellum; distal article 25% of total length of accessory flagellum, with 3 apical setae of different lengths and 1 aesthetasc. Aesthetascs half of respective main flagellum articles ( Fig. 31C View Fig ).

Antenna II ( Fig. 31D View Fig ): flagellum formed of 8 articles and representing 39% of total length of antenna II. Most flagellum articles bear 1 aesthetasc, half the length of respective flagellum articles.

Mouthparts

Labrum ( Fig. 32A View Fig ): typical, subovoid shape. Labium ( Fig. 32B View Fig ). Large inner lobes with 1 row of fine setae on inner sides. Outer lobes with 1 row of fine setae subapically on inner sides.

Maxilla I ( Fig. 32C View Fig ): with 4 apical setae on distal article of palp. Six spines of outer lobe with 1–4 teeth each and 1 spine with several small teeth. Inner lobe with 1 apical seta.

Maxilla II ( Fig. 32D View Fig ): with inner lobe slightly shorter than outer lobe. 1 apical and 1 subapical row of setae on each lobe. 1 row of fine setae on outer margin of outer lobe.

Left mandible ( Fig. 32E View Fig ): 4 teeth on incisor process. 4 teeth on lacinia mobilis. 4 serrate and 1 trifid seta between lacinia mobilis and molar process.

Right mandible ( Fig. 32F View Fig ): 4 teeth on incisor process. Several small denticles on lacinia mobilis. 4 serrate and 4 trifid setae between lacinia mobilis and molar process. Long seta at base of molar process.

Mandibular palps ( Fig. 32E–F View Fig ): highly similar and of same length. 3 articles account for 19% (article 1), 37% (article 2) and 44% (article 3) of total length of palp. Proximal article without setae, median article with 9–10 ventral setae. Distal article of palp with one group of 4 A setae, three groups with 1 B setae each, 9–13 D setae and 6 E setae.

Maxilliped ( Fig. 33A View Fig ): with palp formed of 4 articles. Article 1 with 2 setae on inner margin. Article 2 with 24 setae aligned along inner margin. Article 3 with 3 apical setae, one group of 5 dorsal setae and one group of 7 setae on inner margin. Article 4 with 1 seta located on outer margin and 2 setae at nail insertion. The outer lobe with 3 apical setae and 9 flattened setae on inner margin. Inner lobe provided apically with 7 setae and 1 flattened seta.

Gnathopods

Gnathopod I ( Fig. 33B View Fig ): coxal plate with irregular shape, with depth larger than width (ratio depth:width 1.0: 0.64). Basis length: width ratio 1.0: 0.44. Ischiopodite with one posteroventral group of 3 setae. Basis: carpus length ratio 1.0: 0.6. Carpus with row of 11 setae of various lengths along ventral margin, group of 3 setae located anterodorsally and one group of 5 setae on carpus surface close to ventral margin. Propodite as long as wide, 4 groups of 1–4 setae on ventral margin, one anterodorsal group of 3 setae, one group of 7 anteroapical setae, 2 mesial setae on lateral surface, 2 setae on lateral surface close to ventral margin, and one group of 3 setae close to palmar corner. 1 strong palmar spine, 1 supporting spine and 2 denticulate spines present in palmar corner. Dactylopodite with claw 35% of total dactylopodite length and 2 setae along outer margin.

Gnathopod II ( Fig. 33C View Fig ): slightly larger than gnathopod I, with coxal plate in irregular shape (ratio width: depth 1.0: 0.8). Ovoid gill and of same length as coxal plate width. Basis length: width ratio 1.0: 0.35. Ischiopodite with one posteroventral group of 3 setae. Basis: carpus length ratio 1.0: 0.51. Carpus with row of 11 setae of various lengths along ventral margin, group of 4 setae located anterodorsally and 1 row of 6 setae on carpus surface close to ventral margin. Propodite as long as wide, with 4 groups of 3–5 setae on ventral margin, one anterodorsal group of 5 setae, one anteroapical group of 7 setae, one group of 6 setae on lateral surface close to ventral margin, and one group of 3 long setae in vicinity of palmar corner. 1 strong palmar spine, 1 supporting spine and 2 denticulate spines present in palmar corner. Dactylopodite with claw 30% of total dactylopodite length and 2 setae along outer margin. Pereopods

Pereopod III ( Fig. 34A View Fig ): coxal plate in shape of rectangular trapezoid, with width nearly equal to depth. Propodite:dactylus length ratio 1.0: 0.43. Dactylus, with nail measuring half of total length of dactylus, 1 dorsal seta with plumose tip, and 1 seta at nail base. Pereopod III slightly longer than pereopod IV (pereopod III: pereopod IV length ratio 1.0: 0.96).

Pereopod IV ( Fig. 34B View Fig ): coxal plate in shape of rectangular, width: depth ratio 1.0: 0.87. Propodite: dactylus length ratio 1.0: 0.47. Robust dactylus, with nail measuring half of total length of dactylus; 1 dorsal seta with plumose tip and 1 seta at nail base.

Pereopod V ( Fig. 35A View Fig ): shortest leg (2.00 mm) of inspected male paratype. Coxal plate of irregular shape, with deep concavity on ventral side, 1 anterior and 4 posterior setae. Basis rectangular, length:width ratio 1.0: 0.62, 4 setae on anterior margin, 7 setae on posterior margin, 2 anteroapical setae of different lengths. Dactylus with 1 dorsal seta with plumose tip, 2 setae of different lengths at nail base, which represents ⅓ of total dactylus length. Propodite length:dactylus length ratio 1.0: 0.37.

Pereopod VI ( Fig. 35B View Fig ): coxal plate relatively similar to that of pereopod V, with 1 posterior seta. Basis rectangular, length: width ratio 1.0: 0.58, 5 setae on anterior margin, 10 setae on posterior margin, 4 anteroapical setae of different lengths. Dactylus with 1 plumose seta on outer margin and 2 setae of different lengths near nail base. Nail 22% of total dactylus length. Propodite: dactylus length ratio 1.0: 0.39.

Pereopod VII ( Fig. 35C View Fig ): longest leg ( 2.93 mm) of inspected paratype male. Coxal plate trapezoidal, with 1 seta on posterior margin. Basis rectangular, ratio length: width 1.0: 0.6, 4 setae on anterior margin, 9 setae on posterior margin and 3 anteroapical setae of different lengths. Dactylus with 1 plumose seta on outer margin and 2 setae near nail base. Nail length 29% of total dactylus length. Ratio propodite: dactylus length 1.0: 0.27.

Pereopods V: VI: VII ratio 1.0: 1.40: 1.47.

Pleopods

Pleopods I, II and III similar in shape (pleopod III, with 3 hooks on retinaculum, depicted in Fig. 36A View Fig ), with unequal rami. Pleopods II and III with 2 hooks on retinaculum.

Epimeral plates ( Fig. 36B View Fig )

Epimeral plate I with right postero-ventral angle, straight ventral margin, convex posterior margin with 4 setae. Epimeral plate II with right postero-ventral angle, convex ventral margin with 1 spine, convex posterior margin with 5 spines. Epimeral plate III with right posteroventral angle, convex ventral margin with 2 spines, convex posterior margin with 4 spines.

Uropods

Uropod I ( Fig. 37A View Fig ): with two dorsolateral rows of 2–4 spines on peduncle. Exopodite slightly longer than endopodite, exopodite: endopodite length ratio 1.0: 0.91. 1 strong spine at base of uropod I.

Uropod II ( Fig. 37B View Fig ): with 3 dorsal and 3 apical spines on peduncle. Endopodite longer than exopodite, endopodite: exopodite length ratio 1.0: 0.89, both rami provided with 2 dorsal and 5 apical spines of different lengths.

Uropod III ( Fig. 37C View Fig ): sexually differentiated, longer in males. Peduncle with 3 small apical setae. Short endopodite, 47% of length of peduncle, with 2 apical setae. Proximal segment of exopodite longer than distal segment (ratio 1.0: 0.85). Anterior margin of proximal segment of exopodite with 3 groups of 2–3 setae; posterior margin of exopodite with 4 groups of 1–2 setae; 2 antero- and 2 postero-apical setae. Distal segment of exopodite with 2 setae on anterior margin, 1 seta on posterior margin, 2 subapical and 5 apical setae of different lengths.

Telson

Telson ( Fig. 37E View Fig ): wide (width:length ratio 1.0:0.9), with 5 long apical spines alongside small seta with plumose tip. Two thin setae with plumose tip on outer margin of 1 lobe. Longest spine 43% of telson length.

Sexual dimorphism

The examined male and female are highly similar. Besides the usual sexual dimorphism (e.g., slightly smaller gnathopods, presence of oostegites, and slightly deeper coxal plates I– VI in females), in N. wasgauensis sp. nov., the female uropod III is shorter than that of male ( Fig. 37D View Fig ). The telson of the inspected female paratype ( Fig. 37F View Fig ) is smaller, with 6 spines on one lobe, and 2 fine setae with plumose tip on the outer margin of both lobes.

Type locality, ecology and distribution

The species shows a very narrow distribution limited to the Wasgau region, i.e., Franco-German uplands covering parts of the Federal State of Rhineland-Palatinate ( Germany) and the Departments of Bas-Rhin and Moselle (both France) ( Fig. 38 View Fig ). The type locality is the Sülzlochquelle 2 in the community of Godramstein ( Rhineland-Palatinate, Germany) at 49.2152° N, 8.0842° E (Supp. file 3.7). It is a natural rheocrene spring with a permanent moderate flow, 21°GH hardness and 380 ppm TDS. No other species of either Niphargus or gammarids ( Amphipoda ; Gammaridae ) were found in this spring. Across its known distribution range, it was found in five springs, two abandoned mines and in one gallery of the Siegfried Line. The species seems to be absent in the interstitial environment. Previous published records from the Stollen am Sachsenstein ( Germany), which referred to N. aquilex aquilex ( Weber 1988, 1989), also belong to this species.