Niphargus saraviensis Weber & Brad, 2025

Niphargus saraviensis Weber & Brad sp. nov.

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Figs 39–47 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. Six spines of maxilla I outer lobe with 1–2 teeth each; one spine with several smaller teeth. Mandibular palp with small number (1–2) of B setae. Gnathopods with 1 seta along outer margin of dactylopodite. Pereiopod VII, the longest leg, almost half of total body length. Pleopods retinaculum with 2 hooks. Uropod I, longer exopodite. Uropod II, longer endopodite. Uropod III sexually dimorphic, exopodite elongated in males. Telson with 4 apical spines on each lobe. The COI marker shows two single pure diagnostic sites at positions 94 (A) and 357 (A). Four 28S rDNA alleles are diagnostic (with 7 heterozygous specimens) as well as 23 COI barcodes.

Etymology

The species name derives from the German Federal State of Saarland, in which the type locality is located. In Weber et al. (2023), this species was treated as N. aquilex G.

Material examined

Holotype

GERMANY • ♂; Saarland, Zilla’s Keller in Nunkirchen ; 49.4826° N, 6.8317° E; 30 Dec. 2017; Dieter Weber leg.; kept intact in 96% ethanol; 171230-02; MNHNL130580 . GoogleMaps

Paratypes

GERMANY • 1 ♂; same collection data as for holotype; 30 Dec. 2017; dissected and appendages drawn; 171230-01; ISER microscope slide DW171230-01 GoogleMaps • 1 ♀; same collection data as for preceding; dissected and appendages drawn; 171230-05; ISER microscope slide DW171230-05 GoogleMaps • 1 ♂; same collection data as for holotype; 12 Mar. 2018; ISER DW180312-01 GoogleMaps • 1 ♂; same collection data as for holotype; 12 Mar. 2018; ISER DW180312-06 GoogleMaps • 1 ♀; same collection data as for holotype; 12 Mar. 2018; ISER DW180312- 03 GoogleMaps • 1 ♀; same collection data as for holotype; 30 Dec. 2017; ISER DW171230-07 GoogleMaps • 1 ♂; same collection data as for holotype; 12 Mar. 2018; 180312-02; MNHNL130581 GoogleMaps • 1 ♂; same collection data as for holotype; 12 Mar. 2018; 180312-04; MNHNL130582 GoogleMaps • 1 ♀; same collection data as for holotype; 30 Dec. 2017; 171230-04; MNHNL130583 GoogleMaps • 1 ♀; same collection data as for holotype; 30 Dec. 2017; 171230-06; MNHNL130584 GoogleMaps .

Molecular data

COI and 28S rDNA sequences of specimens belonging to Niphargus saraviensis 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 171230-01)

The total body length is 7.91 mm ( Fig. 39 View Fig ).

Head

Head ( Fig. 39 View Fig ) 6.95% of total body length. Eyes and rostrum absent.

Antennae

Antenna I ( Fig. 40A View Fig ): with main flagellum formed of 18 articles, representing 50% of total body length. Peduncle length ⅓ of total length of antenna I. The accessory flagellum ( Fig. 40B View Fig ) biarticulated; proximal article almost twice as long as first article of main flagellum; distal article ¼ of total length of accessory flagellum, with 2 apical setae of different lengths and one aesthetasc. Aesthetascs slightly more than half of respective flagellum articles ( Fig. 40C View Fig ).

Antenna II ( Fig. 40D View Fig ): flagellum formed of 6 articles and representing 40% of total length of antenna II. Most flagellum articles bear one short aesthetasc.

Mouthparts

Labrum ( Fig. 41A View Fig ): typical, subovoid shape. Labium ( Fig. 41B View Fig ). Relatively small inner lobes with 1 row of fine setae located subapically on inner sides. Outer lobes each with 1 row of fine setae on outer sides, 1 row of fine setae subapically on inner sides and 1 row of fine apical setae.

Maxilla I ( Fig. 41C View Fig ): with 4 apical setae on the distal article of palp. Six spines of outer lobe with 1–2 teeth each and one spine with several smaller teeth. Inner lobe with 1 apical seta.

Maxilla II ( Fig. 41D View Fig ): with inner lobe slightly shorter than outer lobe. 1 apical row of setae each lobe. Inner lobe with 2 subapical setae on inner margin. Outer lobe with 3 smaller setae on outer margin.

Left mandible ( Fig. 41E View Fig ): 5 teeth on incisor process. 3 teeth on lacinia mobilis. 6 serrated setae between lacinia mobilis and molar process.

Right mandible ( Fig. 41F View Fig ): 5 teeth on incisor process. 5 small teeth on lacinia mobilis. 4 serrated setae alternated with 4 trifid setae between lacinia mobilis and molar process. Long seta on molar process.

Mandibular palps ( Fig. 41E–F View Fig ): highly similar and of same length. 3 articles account for 21% (article 1), 37% (article 2) and 42% (article 3) of total length of palp. Proximal article with 1 apical seta. Median article with 7 ventral setae. Distal article of palp with one group of 3 A setae, two groups with 1 B seta each, 23–24 D setae and 6–7 E setae.

Maxilliped ( Fig. 42A View Fig ): with palp formed of 4 articles. Article 1 asetose. Article 2 with 14 setae aligned along inner margin. Article 3 with 5 apical setae, one group of 4 dorsal setae and one group of 5 setae on inner margin. Article 4 with 1 seta located on outer margin and 2 setae at nail insertion. Outer lobe with 3 apical setae and 9 setae on inner margin, of which 7 flattened. Inner lobe provided apically with 1 flattened seta and 5 setae.

Gnathopods

Gnathopod I ( Fig. 42B View Fig ): coxal plate in shape of rectangular trapezoid, with depth larger than width (ratio depth: width 1.0: 0.62). Basis length: width ratio 1.0: 0.40. Ischiopodite with one posteroventral group of 3 setae. Basis: carpus length ratio 1.0: 0.56. Carpus with row of 6 setae along ventral margin, group of 5 setae located anterodorsally and two groups of 2–6 setae on carpus surface close to ventral margin. Propodite nearly as long as wide, 4 groups of 1–4 setae on ventral margin, one group of 3 setae on dorsal margin, one group of 5 anterodorsal setae, one group of 6 anteroapical setae, 1 mesial seta on lateral surface, 1 seta on lateral surface close to ventral margin and one group of 2 setae close to palmar corner. One strong palmar spine, one supporting spine and two denticulate spines present in palmar corner. Dactylopodite with claw 33% of total dactylopodite length and 1 seta along outer margin.

Gnathopod II ( Fig. 42C View Fig ): slightly larger than gnathopod I, with coxal plate in shape of trapezoid; coxal plate slightly wider than long (ratio width: depth 1.0: 0.80). Basis length: width ratio is 1.0: 0.29. Ischiopodite with one posteroventral group of 4 setae. Basis: carpus length ratio 1.0: 0.56. Carpus with row of 8 setae of various lengths along ventral margin, group of 5 setae located anterodorsally and one group of 5 setae on carpus surface close to ventral margin. Propodite almost as long as wide, 5 groups of 2–3 setae on ventral margin, 1 seta on dorsal margin, 1 seta on lateral surface close to ventral margin and 5 anteroapical setae of different lengths. 1 mesial seta on the lateral surface, 3 setae close to palmar corner. 1 strong palmar spine, 1 supporting spine and 2 denticulate spines present in palmar corner. Dactylopodite with claw 40% of total dactylopodite length and 1 seta along outer margin.

Pereopods

Pereopod III ( Fig. 43A View Fig ): coxal plate in shape of trapezoid, ratio width-depth 1.0:0.73. Propodite: dactylus length ratio 1.0: 0.4. Dactylus with nail measuring half of total length of dactylus, 1 dorsal seta with plumose tip. Pereopod III equal slightly longer than pereopod IV (pereopod III: pereopod IV length ratio 1.0: 0.95).

Pereopod IV ( Fig. 43B View Fig ): relatively rectangular coxal plate, width: depth ratio 1.0: 0.75. Propodite: dactylus length ratio 1.0: 0.41. Robust dactylus, with nail measuring half of total length of dactylus; 1 dorsal seta with plumose tip.

Pereopod V ( Fig. 44A View Fig ): coxal plate of irregular shape, with deep concavity on ventral side, 2 anterior setae and 1 posterior seta. Basis rectangular, length:width ratio 1.0: 0.64, 6 setae on posterior margin, 3 setae on anterior margin, 2 anteroapical setae of different lengths. Dactylus with dorsal seta with plumose tip, 2 setae at nail base, which represents 44% of total dactylus length. Propodite length: dactylus length ratio 1.0: 0.31.

Pereopod VI ( Fig. 44B View Fig ): coxal plate smaller than that of pereopod V, but similar in shape and 1 posterior seta. Basis rectangular, length: width ratio 1.0: 0.55, 6 setae on posterior margin, 3 setae on anterior margin and 2 anteroapical setae. Dactylus with 1 plumose seta on outer margin and 1 spine near nail base. Nail length ⅓ of te total dactylus length. Ratio propodite length: dactylus length 1.0:0.33.

Pereopod VII ( Fig. 44C View Fig ): longest leg ( 3.57 mm) of inspected paratype male. Coxal plate trapezoidal, with 1 posterior seta. Basis ovoid-trapezoidal, ratio length:width 1.0: 0.6, 7 setae on posterior margin and 2 setae on anterior margin. Dactylus with 1 plumose seta on outer margin and 2 small setae near nail base. Nail length ⅓ of total dactylus length. Ratio propodite length: dactylus length 1.0: 0.33.

Pereopods V: VI: VII ratio 1.0: 1.38: 1.57.

Pleopods

Pleopods. Similar (pleopod I depicted in Fig. 45A View Fig ), with equal rami and 2 hooks on retinaculum. Epimeral plates ( Fig. 45B View Fig )

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

Uropods

Uropod I ( Fig. 46A View Fig ): with one dorso-lateral rows of 6 spines on peduncle. Exopodite slightly longer than endopodite (ratio 1.0: 0.93). One strong spine at the base of the uropod I.

Uropod II ( Fig. 46B View Fig ): with 2 dorsal spine and 3 apical spines. Endopodite longer than exopodite, endopodite length:exopodite length ratio 1.0:0.83, both rami with 4–5 apical spines.

Uropod III ( Fig. 46C View Fig ): sexually differentiated, longer in males. Peduncle with 2 apical setae. Short endopodite about half length of peduncle, with 2 apical setae. Proximal segment of exopodite longer than distal segment (ratio 1.0: 0.84). Anterior margin of proximal segment of exopodite with 2 groups of 2 setae; posterior margin of exopodite with one group of 2 setae; two groups of 3 apical setae. Distal segment of exopodite with one group of 2 setae on anterior margin, 2 groups of 1–2 setae on posterior margin and 4 apical setae of different lengths.

Telson

Telson ( Fig. 46E View Fig ): as wide as long, with 4 apical spines of different lengths on each lobe. Longest spine slightly longer than half of telson length. 2 thin setae of different lengths and plumose tip on 1 lobe, while other lobe provided with 1 such seta only.

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. saraviensis sp. nov., the female uropod III ( Fig. 46D View Fig ) is shorter comparted to that of the male. The telson of the inspected female paratype ( Fig. 46F View Fig ) is with only 3 apical spines on 1 lobe and without the median plumose setae.

Type locality, ecology and distribution

The species distribution range is very large, with records originating from Central to Southern Germany, Luxembourg, the Czech Republic and Southern France ( Fig. 47 View Fig ). The high frequency of records in Western and Southwestern Germany can most likely be attributed to a high sampling effort in those two regions. The type locality is Zilla’s Keller in Nunkirchen ( Saarland, Germany) at 49.4826° N, 6.8317° E, which is an old subterranean beer cellar dug in a Early–Middle Triassic sandstone formation (Supp. file 3.8). It is nowadays unused and locked. The cellar was bought by the Naturlandstiftung ( Werno & Weber 2008) to keep it protected. Specimens were collected in a small spring (yield <1l/min) at the end of this artificial cavern where it subsists on wood that it regularly renewed (Supp. file 3.9). In a water basin (capacity 100 l) 5 m from this spring, N. saraviensis sp. nov. was not detected. We confirm the permanent presence of this species at the type locality as it was found on 5 January 2013, 10 January 2015, 5 November 2017, 30 December 2017, and 9 October 2018. Niphargus saraviensis seems to be a subterranean-ubiquist (Supp. file 4.5). Previously published records from the Schillerhöhle ( Germany), which referred to N. aquilex aquilex ( Dobat 1968) , also belong to this species.