Niphargus zagorae, Švara, Vid, Delić, Teo, Rađa, Tonći & Fišer, Cene, 2015

Švara, Vid, Delić, Teo, Rađa, Tonći & Fišer, Cene, 2015, Molecular phylogeny of Niphargus boskovici (Crustacea: Amphipoda) reveals a new species from epikarst, Zootaxa 3994 (3), pp. 354-376 : 359-368

Niphargus zagorae sp. n.

( Figs 1 , 2 , 3 a–b, 4a–b, 5 a, c, e, g, 6a, d, 7a–b, 8a–c, 9a–c, 10a, c)

Type material. 5 individuals from type locality (slides #1, 2, 5 juvenile or immature males, slides #3, 4 ovigerous females, voucher No. NB943–NB947), holotype ovigerous female, slide #3, all collected in Golubinka pod Barišinovcem, Croatia, coll. Tonći Rađa, 2007. The type series is deposited in collection of Department of Biology, Biotechnical Faculty, University of Ljubljana.

Type locality. Golubinka pod Barišinovcem, Čvrljevo, Šibenik, Croatia. Coordinates, WGS-84: 43. 696558 °N, 16. 305139 °E

Etymology. The species name is derived from the Latinized Croatian name of the geographical area (Croatian: Zagora) where the new species was collected.

Distribution. Golubinka pod Barišinovcem, near Čvrljevo, vicinity of Šibenik; Kevina jama near Radošić, vicinity of Split; Tomina jama, near Labin dalmatinski, vicinity of Split ( Fig. 1 ).

Description. [Based on holotype; variation among individuals given in square brackets].

Body ( Fig. 3 a, 10c). Body elongated, 9.9 [7.4–9.9] mm long. Head from 0.11 [0.09–0.12] of body length, without rostrum. Pereonite VII with 1 [1–2] postero-ventral setae, pleon segments I–III with 8 [5–10] dorsoposterior setae. Epimeral plates II– III rectangular, with posterior and distal margins convex. Epimeral plates II–III with 4–5 [3–5] setae posteriorly; subventrally with 1 [1–2] and 2 spines respectively. Urosomites I–III with 1, 2, and 1 dorsolateral spines, respectively, 1 each side of body. Base of uropod with 1 strong seta.

Telson ( Fig. 10 c) length:width ratio as 1:1.1 [1:0.95–1.1], telson cleft 0.67 [0.65–0.75] of telson length. Telson with 3 [3–4] apical spines (per lobe), 0 [0–1] lateral spines (per lobe), 0–1 [0–1] mesial (per lobe) and 2 [0–2] dorsal spines (per lobe). Laterally two plumose setae on each lobe. Longest apical spines as long as 0.33 [0.30– 0.38] of telson length.

Antennae I ( Fig. 4 a, b). Length 0.40 [0.35–0.40] of the body length. Peduncle segments 1–3 in ratio 1:82:38 [1:(0.73–0.82):(0.36–0.40)], flagellum of 26 [17–26] articles, each bearing 1 seta and 1 aesthetasc. Accessory flagellum biarticulated, distal article about 1/3 of the length of basal article.

Antennae II ( Fig. 4 b) 0.49 [0.49–0.55] of antenna I length. Lengths of peduncle articles 4:5 as 1:0.86 [1:(0.86– 0.95)]. Flagellum II with 11 [8–11] articles, each bearing short seta and another chemosensory seta.

Mouthparts ( Fig. 5 a, c, e, g). Left mandible pars incisiva with 4 teeth and lacinia mobilis with four teeth, pars molaris triturative. Right mandible ( Fig. 5 a) with 4-dentate incisor blades, multidenticulated lacinia mobilis and 6 plumose setae between lacinia and triturative molar.

Mandibular palp tri-articulate, basal article without setae, middle article with 5–9 long setae along inner margin, distal article with group of 6 [1–6] A setae, 4 [3–4] groups of B setae, 24 [19–24] D setae and 4 [3–4] E setae. Palp articles 2 and 3 in ratio 1:1.24 [1:1.20–1.35].

Maxilla I ( Fig. 5 c) with 4 [2–4] setae on inner lobe, outer lobe with 7 spines; innermost spine pluridentate, others with up to 2 denticles. Palp biarticulated, with 7 [5–7] distal and subdistal seta.

Maxilla II ( Fig. 5 e) with sub-equal lobes, each with a group of long apical and subapical seta. Labium with inner lobes.

Maxilliped ( Fig. 5 g) inner lobe with 2 [2–3] strong flattened spines and 7 [6–8] strong plumose setae apically and subapically. Outer lobe with 10 [7–10] strong mesial flattened spines and 5 [5–6] plumose apical seta. Dactylus with setae at base of nail.

Gnathopods. Gnathopod I ( Fig. 6 a) coxa of rhomboid shape with 9 [6–9] setae ventrodistally. Article 2 length: width as 1:0.44 [1:(0.41–0.50)]. Article 3 with one row of 8 [5–9] posteroventral setae. Article 5 length 0.80 [0.78– 0.86] length of article 6. Article 5 with proximal bulb; 1 group of setae distoanteriorly; setae also on bulb and along posteromesial margin. Article 6 rectangular in shape, antero-distal corner slightly inclined. Anterior margin with 3 [2–3] groups of setae (in total 14 [9–14] setae) and antero-distal group of 11 [8–11] setae. Posterior margin with 6 [5–6] rows of setae. Palmar corner with long palmar spine, small smooth inner spine and 2 [2–3] outer denticulated spines. Outer surface proximal to palmar spine with group of 3 [2–3] long setae; inner surface with several groups of small setae. Dactylus with 6 [4–6] single setae along outer margin, inner margin with small setae; nail 0.25 [0.25–0.33] of dactylus length.

Gnathopod II ( Fig. 6 d) coxa with 7 [6–8] setae distoventrally, width: length ratio as 1:0.87 [1:(0.87–0.97)]. Article 2 length: width as 1:34 [1:(0.30–0.35)]. Article 3 with one row of 4 [2–4] posteroventral setae. Length of article 5 is 0.86 [0.86–0.91] of article 6 length. Article 5 with proximal bulb; 1 group of setae disto-anteriorly; setae also on bulb and along posteromesial margin. Article 6 of gnathopod II larger than article 6 of gnathopod I (circumference of gnathopods I:II as 0.78:1 [0.78–0.85:1]); rectangular in shape, anterodistal angle strongly inclined and palm longer as length of article. Anterior margin with 2 [2–3] groups of setae (in total 5 [4–6] setae) and anterodistal group of 8 [6–8] setae. Posterior margin with 9 [7–9] rows of setae. Palmar corner with long palmar spine, small smooth inner spine and 2 [1–2] outer denticulated spines. Outer surface proximal to palmar spine with 2 long setae; inner surface with several groups of small setae. Dactylus with 6 [4–6] single setae along outer margin, inner margin with small setae; nail 0.28 [0.28–0.32] of dactylus length.

Pereopods III–IV ( Fig. 7 a, c). Pereopods III:IV as 1:0.98 [1:(0.94–0.98)]; coxal plates III–IV width:length as 1:0.89 [1:(0.82–0.89)] and 1:1.10 [1:(0.97–1.10)], respectively; ventral margins with 6–9 [4–9] setae. Each dactylus with 2 tiny setae at the base of nail and 1 plumose seta dorsally; nail IV 0.50 [0.45–0.52] of dactylus length, dactylus IV 0.48 [0.42–0.48] of propodus length.

Pereopods V–VII ( Fig. 8 a–c). Coxae V–VI with anterior lobe, posterior margin with 2 and 3 [1–3] setae, distal seta may be spine-like. Coxa VII semicircular, 1 seta posteriorly. Lengths of pereopods V:VI:VII as 1:1.25:1.38 [1:(1.25–1.30):(1.33–1.38)]; pereopod VII 0.49 [0.42–0.49] of body length. Articles 2 ovoid, with small distoposterior lobe, respective widths:lengths as 1:0.68 [1:(0.69–0.76)], 1:0.60 [1:(0.60–0.73)], 1:0.63 [1:(0.63–0.71)]. Bases (articles 2) of pereopods V–VII with 9 [9–10], 12 [9–12], 12 [9–12] posterior setae and 6 [5–6], 5 [5–6], 6 [5–6] anterior groups of setae and spines, respectively. Each dactylus with 2 tiny setae at the base of nail, or with 1 tiny seta and 1 tiny spine; 1 plumose seta dorsally; nail VII 0.33 [0.33–0.38] of dactylus length, dactylus VII 0.28 [0.28–0.31] of propodus length.

Gills oval shaped.

Pleopods ( Fig. 10 a) inner ramus longer than outer, each ramus of 10 and 11 [9–11] articles, 2 retinaculae on each pleopod.

Uropods I–III. Uropod I ( Fig. 9 a) basipodite with 6 lateral and 2 [2–3] mesial spines. Endopodite with 2 groups of totally 7 [6 or 7] spines and setae and 5 apical spines, exopodite with 4 [2–4] groups of totally 11 [2–11] spines and 5 apical spines. Endopodite:exopodite lengths as 1:1.08 [1:(1.03–1.09)].

Uropod II ( Fig. 9 b) endopodite:exopodite lengths as 1:1.14 [1:(1.08–1.17)].

Uropod III ( Fig. 9 c) basipodite with no [0–1] lateral spines and 7 [7–10] apical spines. Exopodite proximal article with 6 [5–6] and 5 [4–6] groups of spines, setae and plumose setae along inner and outer margin respectively. Apical article of exopodite with no [0–1] setae laterally and 8 [5–8] setae apically. Endopodite with 0– 1 lateral spines and 3 or 4 apical spines and setae. Distal article of exopodite as 0.14 [0.13–0.20] (females) of proximal article, total uropod III as 0.19 [0.17–0.21] of body length (females).

Remarks. Niphargus zagorae sp. n. is similar to N. boskovici , but differs from the latter: i) by the presence of spine on urosomite III; ii) slightly larger and more inclined propods of gnathopods II; iii) at bases of nails of dactyls of pereopods III–IV only setae are present; and iv) pereopod V is proportionally longer when compared to pereopods VI and VII.

The material we studied was limited, and it is not clear whether males are sexually differing from the females.

Figures

FIGURE 1. Phylogenetic position and distribution of the studied species. Left side: Bayesian phylogenetic tree of 94 Niphargus species. Support for the nodes is labeled with color (posterior probability 1 — black, posterior probability 0.99 — grey, posterior probability> 0.95 — white). Detailed phylogenetic structure of the shaded clade containing focal species is presented on the right side. Geographic distribution of the N. zagorae, N. boskovici, N. hvarensis and N. miljeticus (blackcolored lineage in clade upper right) is presented on a bottom right map. Distribution of newly described species is presented with asterisk. Abbreviations—CRO—Croatia, BIH—Bosnia and Herzegovina, MNE—Montenegro.

FIGURE 2. Differences in proportions between N. zagorae sp. n. (circles) and N. boskovici (diamonds). Upper: The ratio propodus length: palm length of gnathopod II plotted against the body size. Lower: The ratio pereopod V length: pereopod VII length plotted against body size. We plotted body proportions against body size as some appendages may grow allometrically (Fišer et al. 2008 b). Note that values of ratio do not overlap between the two species.

FIGURE 3. Habitus and diagnostic details (arrows) on urosoma in N. zagorae sp. n. (a, b) and N. boskovici (c, d).

FIGURE 4. Antenna I and II of N. zagorae sp. n. (a, b) and N. boskovici (c, d).

FIGURE 5. Mouthparts of N. zagorae sp. n. (a, c, e, g) and N. boskovici (b, d, f, h, i, j). Mandibula (a, b), maxilla I (c, d), maxilla II (e, f), maxilliped (g, h), labrum (i), labium (j).

FIGURE 6. Gnathopods I and II of N. zagorae sp. n. (a, d) and N. boskovici (b, c).

FIGURE 7. Pereopods III and IV of N. zagorae sp. n. (a, b) and N. boskovici (c, d) with more precise drawing of dactylus of the third pereopods. Arrows indicate diagnostic difference.

FIGURE 8. Pereopods V, VI and VII of N. zagorae sp. n. (a, b, c) and N. boskovici (d, e, f).

FIGURE 9: Uropods I, II and III of N. zagorae sp. n. (a, b, c) and N. boskovici (d, e, f). Uropod III of N. boskovici is distally damaged; unfortunately it was the only adult male in analysis.

FIGURE 10. Pleopods and telson of N. zagorae sp. n. (a, c) and N. boskovici (b, d).