Niphargus palatinensis Weber & Brad & Weigand 2025, sp. nov.

Niphargus palatinensis Weber & Brad sp. nov. urn:lsid:zoobank.org:act: 5DA10A74-7763-41C9-B0ED-76AD156C03D4 Figs 12–20 Diagnosis Medium-sized Niphargus species, poorly setose. Right postero-ventral angle of epimeral plates. Six 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 1 seta along outer margin of dactylopodites. Pereiopod VII, the longest leg, almost half of total body length. Pleopods retinaculum with 3 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 six pure diagnostic sites at positions 31 (C), 184 (C), 223 (G), 353 (G), 358 (G) and 391 (A). A single 28S rDNA allele is diagnostic as well as 21 COI barcodes. Etymology The species name derives from the German Federal State of Rhineland-Palatinate, where the type locality is located. In Weber et al. (2023), this species was treated as N. aquilex A. Material examined Holotype GERMANY • ♂; Rhineland-Palatinate, Waldleiningen, Felsenbrunnen in the Palatinate Forest in the Middle Buntsandstein; rheocrene spring; 49.2881° N, 7.8467° E; 14 Dec. 2016; Dieter Weber leg.; kept intact in 96% ethanol; 161214-02; MNHNL130574. Paratypes GERMANY • 1 ♂; same collection data as for holotype; 14 Dec. 2016; dissected and appendages drawn; 161214-01; ISER microscope slide DW161214-01 • 1 ♀; same collection data as for holotype; 8 Aug. 2017; dissected and appendages drawn; 170808-13; ISER microscope slide DW170808-13. Molecular data COI and 28S rDNA sequences of specimens belonging to Niphargus palatinensis 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 161214-01) Measurements Total body length 6.92 mm (Fig. 12). Head Head (Fig. 12) 8% of total body length. Eyes and rostrum absent. Antennae Antenna I (Fig. 13A): with main flagellum formed of 20 articles, representing 50% of total body length. Peduncle length 35% of total length of antenna I. The accessory flagellum (Fig. 13B). Biarticulated; proximal article shorter than first article of main flagellum; distal article 27% of total length of accessory flagellum, with 4 apical setae of different lengths and 1 aesthetasc. Aesthetascs ¾ of respective main flagellum articles (Fig. 13C). Antenna II (Fig. 13D): flagellum formed of 10 articles and representing 50% of total length of antenna II. Most flagellum articles bear 1 aesthetasc, longer than half of respective flagellum articles. Mouthparts Labrum (Fig. 14A): typical, subovoid shape. Labium (Fig. 14B). Large inner lobes with 1 row of fine setae on inner sides. Outer lobes with 2 rows of fine setae subapically on inner sides. Maxilla I (Fig. 14C): with 3 apical setae on distal article of palp. 6 spines of outer lobe with 1–3 teeth each and 1 spine with several small teeth. Inner lobe with 1 apical seta. Maxilla II (Fig. 14D): with inner lobe slightly shorter than outer lobe. 1 apical row of setae and 4 setae on inner margin of each lobe. Left mandible (Fig. 14E): 6 teeth on incisor process. 5 teeth on lacinia mobilis. 8 serrated setae intercalated with 4 trifid setae, between lacinia mobilis and molar process. Right mandible (Fig. 14F): 5 teeth on incisor process. Lacinia mobilis with several smaller teeth. 7 serrated and 2 trifid setae between lacinia mobilis and molar process. A long seta on molar process. Mandibular palps (Fig. 14E–F): highly similar and of same length. 3 articles account for 17% (article 1), 39% (article 2) and 44% (article 3) of total length of palp. Proximal article without setae, median article with 8 ventral setae. Distal article of palp with one group of 3 A setae, three groups with 1 B setae, 17 D setae and 5–6 E setae. Maxilliped (Fig. 15A): with palp formed of 4 articles. Article 1 with 2 setae on inner margin. Article 2 with 23 setae aligned along inner margin. Article 3 with 4 apical setae, one group of 6 dorsal setae and one group of 7 setae on inner margin. Article 4 with 1 seta located on outer margin and 2 fine setae at nail insertion. Outer lobe with 5 apical setae and 9 flattened setae on inner margin. Inner lobe provided apically with 3 setae, 1 flattened seta and 2 dorsal setae. Gnathopods Gnathopod I (Fig. 15B): coxal plate in shape of rectangular trapezoid, 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: 0.58. Carpus with row of 7 setae along ventral margin, group of 5 setae located anterodorsally and one group of 8 setae on carpus surface close to ventral margin. Propodite as long as wide, three groups of 3–4 setae on ventral margin, one group of 4 setae on dorsal margin, one group of 10 anteroapical setae, 3 mesial setae on lateral surface, 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 26% of te total dactylopodite length and 1 seta along outer margin. Gnathopod II (Fig. 15C): slightly larger than gnathopod I, with coxal plate in shape of trapezoid; coxal plate width larger than depth (ratio width:depth 1.0: 0.7). Basis length: width ratio 1.0:0.31. Ischiopodite with one posteroventral group of 4 setae. Basis: carpus length ratio 1.0:0.54. Carpus with row of 6 setae along ventral margin, group of 4 setae located anterodorsally and 1 row of 4 setae on carpus surface close to ventral margin. Propodite as long as wide, with 5 groups of 3 setae on ventral margin, 4 setae on dorsal margin, 1 mesial seta on lateral surface, 8 anteroapical setae, one group of 5 setae on lateral surface close to ventral margin, and 3 setae close to palmar corner. 1 strong palmar spine, 1 supporting spine and 2 denticulate spines present in palmar corner. Dactylopodite with claw 28% of total dactylopodite length and 1 seta along outer margin. Pereopods Pereopod III (Fig. 16A): coxal plate in shape of rectangular, with width larger than depth, width: depth ratio 0.7. Propodite: dactylus length ratio 1.0: 0.45. Dactylus, with nail measuring half of total length of dactylus, 1 dorsal seta with plumose tip, and 1 seta at nail base. Pereopod III nearly equal to pereopod IV (pereopod III: pereopod IV length ratio 1.0: 0.98). Pereopod IV (Fig. 16B): relatively rectangular coxal plate, with concavity on posterior margin, width: depth ratio 1.0: 0.7. Propodite: dactylus length ratio 1.0: 0.54. Robust dactylus, with nail half of total length of dactylus; 1 dorsal seta with plumose tip and 1 seta at nail base. Pereopod V (Fig. 17A): coxal plate of irregular shape, with deep concavity on ventral side, 4 anterior setae and 1 posterior seta. Basis rectangular, length: width ratio 1.0: 0.57, 4 setae on anterior margin, 9 setae on posterior margin, 3 anteroapical setae of different lengths. Dactylus with 1 dorsal seta with plumose tip, 1 seta at nail base, which represents 45% of total dactylus length. Propodite length: dactylus length ratio 1.0:0.36. Pereopod VI (Fig. 17B): coxal plate smaller than that of pereopod V, with concavity on ventral side less deep than that of pereopod V, and 1 posterior seta. Basis rectangular, length:width ratio 1.0: 0.55, 4 setae on anterior margin, 8 setae on posterior margin, 2 anteroapical setae. Dactylus with 1 plumose seta on outer margin and 2 setae of different lengths near nail base. Nail 36% of total dactylus length. Ratio propodite: dactylus length 1.0: 0.33. Pereopod VII (Fig. 17C): longest leg (3.22 mm) of inspected paratype male. Coxal plate trapezoidal, with 1 seta on posterior margin. Basis rectangular, ratio length: width 1.0: 0.5, 3 setae on anterior margin, 14 setae on posterior margin and 2 small anteroapical setae. Dactylus with 1 plumose seta on outer margin and 2 setae near nail base. Nail length 31% of total dactylus length. Ratio propodite: dactylus length 1.0: 0.3. Pereopods V: VI: VII ratio 1.0: 1.35: 1.42. Pleopods Pleopods. Similar (pleopod III depicted in Fig. 18A), with unequal rami and 3 hooks on retinaculum. Epimeral plates (Fig. 18B) Epimeral plate I with right postero-ventral angle, relatively straight ventral margin, convex posterior margin with 6 setae. Epimeral plate II with right postero-ventral angle, convex ventral margin with 3 spines, convex posterior margin with 6 setae. Epimeral plate III with right posteroventral angle, convex ventral margin with 3 spines, convex posterior margin with 6 setae. Uropods Uropod I (Fig. 19A): with two dorso-lateral rows of 6–8 spines on peduncle. Exopodite slightly longer than endopodite, ratio exopodite: endopodite lengths>plural correct? 1.0: 0.82. 1 strong spine at base of uropod I. Uropod II (Fig. 19B): with 5 dorsal spines and 1 apical spine on peduncle. Endopodite slightly longer than exopodite, endopodite: exopodite length ratio 1.0: 0.88, both rami provided with 4–6 dorsal and 4 apical spines. Uropod III (Fig. 19C): sexually differentiated, longer in males. Peduncle with 5 apical, 3 anterior and 1 posterior setae. Endopodite 62% of length of peduncle, with 3 apical setae, 1 subapical and 1 lateral seta on ventral margin. Proximal segment of exopodite shorter than distal segment. Distal: proximal articles length ratio 1.0: 0.93. Anterior margin of proximal segment of exopodite with 6 groups of 1–3 setae (including plumose setae); posterior margin of exopodite with 5 groups of 1–2 setae; 3 antero- and 3 posteroapical setae. Distal segment of exopodite with 4 groups of 2 setae on anterior margin, 4 setae on posterior margin, and 7 apical setae of different lengths. Telson Telson (Fig. 19E). Nearly as wide as long (length:width ratio 0.95), with 2 subapical and 4 apical spines of different lengths on each lobe. Longest spine 60% of telson length. 2 th