Niphargus dabarensis, Fišer & Trontelj & Sket, 2006

Fišer, Cene, Trontelj, Peter & Sket, Boris, 2006, Phylogenetic analysis of the Niphargus orcinus species- aggregate (Crustacea: Amphipoda: Niphargidae) with description of new taxa, Journal of Natural History (J. Nat. Hist.) 40 (41 - 43), pp. 2265-2315 : 2283-2288

Niphargus dabarensis n. sp. ( Figures 6 , 12–15 )

Type locality. Dabarska pečina, Bosnia and Herzegovina.

Material examined. Cave Dabarska pećina, Bosnia and Herzegovina; July 2004; coll. P. Trontelj; 1 female.

Holotype: female, 25.5 mm (two slides).

Holotype deposited in the collection of Oddelek za biologijo, Biotehniška fakulteta, Univerza v Ljubljani ( Department of Biology , Biotechnical Faculty , University of Ljubljana).

Etymology. The epithet dabarensis is derived from the type locality.

Diagnosis

Telson with 5 apical spines per lobe, 1 spine on dorsal surface and without lateral and medial spines. Antenna I 0.95 of body length. Carpus I–II with proximal bulge large (1/3 of carpus length), gnathopod II propodus large ([length+width+diagonal] 0.25 of body length;) gnathopod propodi I:II (length+width+diagonal) is 1:0.75. Denticulated spines in palmar corner of gnathopod II on inner side. Coxal plates V–VI disto-posteriorly produced; bases V–VI posteriorly with setae and spines; basis VII with slightly developed proxiposterior lobe; all bases narrow, without disto-posterior lobe; dactyls V–VII with 2–3 dorsal plumose setae. Uropod I–II with plumose setae.

Description

Head and trunk ( Figures 6 , 14 ). Body length up to 25.5 mm. Head length 9% of body length; rostrum absent. Pereonites I–VI without setae; pereonite VII with 3 postero-ventral setae.

Pleonites I–III with 17–19 dorso-posterior spines. Epimeral plate II: angle of posteroventral corner sub-rectangular; posterior margin sinusoidal; ventral margin convex; along ventral margin 2 spines, along posterior margin 7 setae. Epimeral plate III: angle of posteroventral corner acute; posterior margin straight to concave; ventral margin convex to straight; along ventral margin 3 spines; along posterior margin 10 setae.

Urosomite I postero-dorso-laterally with 4 spines; urosomite II postero-dorso-laterally with 5 spines; urosomite III postero-dorso-laterally without setae and/or spines. At the base of uropod I 1 spine.

Telson length:width is 1:0.85; cleft 0.6 of length; apical spines 0.35 of length. Plumose setae inserted laterally in the middle part of telson. Telson only with 5 apical spines and 1 dorsal surface spines per lobe.

Antennae ( Figure 12 ). Antenna I 0.93 of body length. Flagellum of antenna I with 65 articles; each article with 1–2 aesthetascs. Peduncle articles in ratio 1:1.1:0.6. Proximal article of peduncle dorso-distally slightly produced. Accessory flagellum biarticulated; distal article shorter than half of proximal article length.

Length ratio antenna I:II as 1:0.33. Flagellum of antenna II with 19 articles; aesthetascs absent. Peduncle articles lengths 4:5 is 1:1.05; flagellum 0.6 of peduncle length (articles 4+5). Article 4 of antenna II peduncle proximally with ventral row of fine setae.

Mouth parts ( Figure 12 ). Inner lobes of labium longer than half of the outer lobes.

Left mandible: incisor with 5 teeth, lacinia mobilis with 4 teeth; between lacinia and molar row of serrated spines, long seta at the base of molar. Right mandible: incisor process with 4 teeth, lacinia mobilis with several small denticles, a row of serrated setae and molar process with a long basal seta. Mandibular palp articles 2:article 3 (distal) is 1:1.25. Proximal palp article without setae; the second article with 9 setae groups and single setae; distal article with 1 A group of 14 setae; 5 B groups; 37 D single setae; 5 E single setae.

Maxilla I distal palp article with 8 apical setae. Outer lobe of maxilla I with 7 uni-, bi- or pluri-toothed spines; inner lobe with 10 setae.

Maxilla II inner lobe slightly smaller than outer lobe; both of them with numerous apical setae.

Maxilliped palp article 2 with 11 rows of setae along inner margin; distal article with a dorsal seta and a group of small setae at the base of the nail. Outer lobe with 15 flattened spines and 10 serrated setae; inner lobe with 4 flattened apical spines and 6 serrated setae.

Coxal plates, gills ( Figures 6 , 13–15 ). Coxal plate I of rhomboid shape, antero-ventral corner pointed; anterior and ventral margin of coxa I with 11 setae. Coxal plate II width:depth is 1:0.8; anterior and ventral margin with 12 setae. Coxal plate III width:depth is 1:0.75; antero-ventral margin with 10 setae. Coxal plate IV width:depth is 1:0.85; posteriorly slightly concave (0.1–0.2 coxa width); antero-ventral margin with up to 14 setae. Coxal plates V–VI: anterior lobe developed, coxae disto-posteriorly produced; on posterior margin 1 seta. Coxal plate VII half-elliptic, ventral margin slightly concave; posterior margin with 1 seta. Gills II–VI large, irregularly ovoid.

Gnathopod I ( Figure 13 ). Ischium with postero-distal row of setae. Carpus 0.5 of basis length and 0.7 of propodus length. Anterior margin of carpus only with distal group of setae; carpus posteriorly with transverse rows of setae proximally, a row of lateral setae and rows of submarginal setae; postero-proximal bulge large (1/3 of carpus length), positioned proximally. Propodus large ‘‘hoof’’ shaped, palm long, convex and oblique. Posterior margin with 14 rows of denticulated setae. Anterior margin with 32 setae in 4 groups; antero-distal group with 11 setae. Group of 4 facial setae proximally of palmar spine; small groups of surface setae present. Palmar corner with strong palmar spine, single supporting spine on inner surface and 3 denticulated spines on outer side. Nail length 0.2 of total dactylus length; along anterior margin 11 single setae; short setae along inner margin present.

Gnathopod II ( Figure 13 ). Basis width:length is 1:0.3. Ischium with postero-distal row of setae. Carpus 0.5 of basis length and 0.75 of propodus length. Anterior margin of carpus with distal group of setae; carpus posteriorly with transverse rows of setae proximally, a row of lateral setae and rows of submarginal setae; postero-proximal bulge large (1/3 of carpus length), positioned proximally. Propodus large (compared to the body), much larger than propodus of gnathopod I. Propodus large ‘‘hoof’’-shaped, palm long, convex and oblique. Posterior margin with 17 rows of denticulated setae. Anterior margin with 13 setae in 4 groups; antero-distal group with 12 setae. Group of 4 facial setae proximally of palmar spine; small groups of surface setae present. Palmar corner with strong palmar spine, single supporting spine and 2 denticulated spines on inner surface. Nail length 0.2 of total dactylus length. Along anterior margin 7 single and a pair of setae (totally 9 setae); short setae along inner margin present.

Pereopods III–IV ( Figure 14 ). Lengths of pereopods III–IV equal (1:1). Dactylus IV 0.45 of propodus IV length; nail length 0.45 of total dactylus length. Dactyla III–IV with dorsal plumose seta; at the base of nail a weak spine.

Pereopods V–VII ( Figure 15 ). Lengths of pereopods V:VI:VII is 1:1.25:1.25. Pereopod VII length 0.7 of body length.

Bases V–VII length:width is 1:0.5–0.55; posterior margin straight or slightly convex; distal lobes absent; posteriorly with 24 (basis V), 13 (basis VI) or 11 (basis VII) setae and spines; anteriorly with 7–8 single slender spines and/or groups of slender spines and/or setae. Postero-proximal lobe on basis VII slightly developed. Lengths relation of propodus:dactylus is 1:0.25. Dactyli V–VII with 2–3 plumose setae; at the base of nail a spine and a seta.

Pleopods and uropods ( Figure 14 ). Pleopods I–III with 2-hooked retinacles each and few setae. Pleopod II rami of 25–28 articles each.

Uropod I protopodite with 7 dorso-lateral spines and 5 dorso-medial spines. Exopodite:endopodite length is 1:1.05; rami straight. Uropod I rami with groups of spines and/or setae along lateral and medial side. Endopodite with 8 setae and/or spines in 4 groups of spines and/or setae; apically 5 spines. Exopodite with 21 setae and/or spines in 6 groups of spines and/or setae; apically 5 spines.

Uropod II exopodite:endopodite length is 1:1.05.

Uropod III length 0.2 of body length. Protopodite with 2 lateral spines and 8 apical spines and setae. Endopodite 0.5 of protopodite length; apically with 1 spine and 1 plumose seta; laterally 2 setae. Exopodite of uropod III slightly flattened; distal article 0.12 of proximal article length. Proximal article with 6 groups consisting of setae, plumose setae and spines along inner margin and 3 groups of spines and setae along outer margin. Distal article of exopodite without lateral setae; apically 3 spines and 3 setae.

Variability. Only one female was studied. Another specimen found is preserved in 96% ethanol for molecular analyses.

Remarks and affinities. Size and shape of propodus of gnathopods I–II as well as position of palmar spines on gnathopod II are characteristic for species N. arbiter , N. salonitanus , N. rejici and N. lourensis . From these taxa, N. dabarensis can be distinguished by features that are shared with N. vjetrenicensis , N. bilecanus , N. hercegovinensis and N. trullipes : large bulge on carpus I–II, disto-posteriorly produced coxal plates V–VI, by the presence of proximoposterior lobe of basis VII, dactyls V–VII with 2–3 dorsal plumose setae as well as uropods I–II with plumose setae. Finally, narrow bases without distal lobes of pereopods V–VII and such a long antenna I (similar as in N. croaticus and N. balcanicus ) are not present in any of the above listed species.

Figures

Figure 6. N. dolichopus sp. n. (above) and N. dabarensis sp. n. (below). Holotypes, lateral view.

Figure 12. Niphargus dabarensis sp. n., holotype. Mouthparts.

Figure 13. Niphargus dabarensis sp. n., holotype. Gnathopod I (above) and gnathopod II (below).

Figure 14. Niphargus dabarensis sp. n., holotype. Pereopods III–IV, detail of pereopod IV dactylus. Uropods I–III. Telson.

Figure 15. Niphargus dabarensis sp. n., holotype. Pereopods V–VII. Details of pereopod VII.