Notoraja sapphira, Séret, Bernard & Last, Peter R., 2009

Séret, Bernard & Last, Peter R., 2009, Notoraja sapphira sp. nov. (Rajoidei: Arhynchobatidae), a new deepwater skate from the slopes of the Norfolk Ridge (South-West Pacific), Zootaxa 2153, pp. 24-34 : 25-33

Notoraja sapphira sp. nov.

Figs 1–7 ; Tables 1–2

Pavoraja sp. n. 2 (violette): Séret in Grandperrin et al., 1997, listed.

Notoraja sp. D (NFZ): Last & Séret in Anonymous 2006, listed in Appendix 5, photos in Appendix 8: 6.

Holotype. NMNZ P 39528, adult male 360 mm TL, Norfolk Ridge, NORFANZ, St. 145, 34°17’84 S, 168°25’82 E, 1251–1268 m depth, 2 June 2003.

Paratypes (4 specimens). MNHN 1997–3591, female 413 mm LT, Norfolk Ridge, HALIPRO 2, St. BT 46, 25°41’0 S, 167°25’0 E, 1230–1268 m depth, 15 Nov. 1996; CSIRO H 6071–01, female 342 mm TL, Norfolk Ridge, NORFANZ, St. 120, 32°36’57 S, 167°50’33 E, 1303–1313 m depth, 30 May 2003; NMNZ P 39536, female 355 mm TL, Norfolk Ridge, St. 146, 34°14’33 S, 168°21’18 E, 1195–1202 m depth, 3 June 2003; NMV A 25171 –002, female 377 mm TL, same data as NMNZ P 39356.

Diagnosis. A medium-size (413 mm TL) species of the genus Notoraja with the following combination of characters: disc heart-shaped with a short projected snout tip; disc slightly wider than long, disc width 51–54% of TL, disc length 47–48% TL; snout short, preorbital snout length 12–15% TL, preoral snout length 12–15% TL; interorbital width 3.6–4.1% TL; interspiracular width 6.0–6.6% TL; tail long and slender, length from posterior margin of cloaca to tip of tail 54–58% TL; dorsal surface of disc largely free of dermal denticles; rostrum with some denticles but without thorns; a small but distinct preorbital thorn on anterior upper orbital rim; denticles present on posterior mid-dorsal trunk; tail prickly with dense, irregular and randomly arranged thorns; mid-dorsal row on tail hardly distinct from the rest of thorn pattern; ventral surface of disc and tail naked; tooth rows 29–36 in upper jaw and 28–32 in lower jaw; pectoral-fin radials 67–70; monospondylous trunk centra 23–25; predorsal caudal diplospondylous centra 70-74; total number of centra 126–134; dorsal surface rich blue, uniform, with a narrow blackish outer margin; ventral surface of disc and tail brownish black, gill slits darker, cloaca opening and mouth corners whitish.

Description. Disc heart-shaped, 1.1 times as broad as long in holotype and paratypes; maximum angle in front of spiracles 90°(100–108°); tip of snout forming a short triangular projection; anterior margin of disc slightly and regularly convex from anterior extension of propterygium to pectoral outer corner in female paratypes; anterior margin of disc undulated in adult male holotype, concave at either side of tip of snout, convex from anterior extension of propterygium to anterior margin of orbit, then concave to level of spiracle; pectoral corner and posterior margin of disc broadly rounded, inner pectoral corner also rounded. Axis of greatest width at 58.4% (56.6–59.1%) of disc length. Preorbital snout length 3.5 (2.6–3.9) times orbit diameter, 3.3 (3.2–4.0) times interorbital width; preoral snout length 2.0 (1.8–2.2) times internarial distance. Orbit diameter 1.0 (0.8–1.3) times interorbital distance, 1.8 (1.6–2.4) times length of spiracles. Nasal curtain with a weak rounded process along lateral margin (except in CSIRO H 6071–01), posterior lobe of the nasal curtain broadly rounded, posterior margin coarsely fringed. Upper and lower jaws slightly arched on either side of symphysis; upper jaw slightly indented in adult male holotype. Teeth with oval crown and a short bluntly cusps in female and pointed cusps in male holotype; arranged in quincunx in females and in diagonal rows in mature male holotype. Distance between first gill slits 1.8 (1.8–1.9) times as great as between nostrils; distance between fifth gill slits 1.1 (1.2–1.4) times as great as between nostrils.

Pelvic fins deeply incised with lobes connected by radials and membranes, anterior lobe moderately long, moderately narrow at base and tapering to blunt point; posterior lobe with convex lateral margins; anterior lobe about as long as the posterior lobe, 0.9 (0.8–1.0) times in posterior lobe. Tail long and slender, narrow at base, depressed over length, slightly convex ventrally, and tapering gradually posteriorly, very slender toward tip; width at axils of pelvic fins 1.9 (2.4–2.7) times width at midlength of tail and 3.5 (3.2–3.8) times width at dorsal-fin origin respectively; tail length from rear of cloaca 1.3 (1.3–1.4) times distance from tip of snout to rear of cloaca; tail width 1.7 (1.5–1.7) times height at axils of pelvic fin and width at first dorsal-fin origin 1.8 (1.6–2.0) times height; lateral skin folds originating anterior to tips of posterior pelvic-fin lobes, extending to distal half of epichordal caudal-fin lobe and broadening distally to slightly narrower than height of epichordal lobe of caudal fin. Dorsal fins of similar shape and size; rather short and moderately tall with evenly convex anterior margin, straight or slightly convex posterior margin, and a pointed or acutely rounded tip; generally separated by very short interspace, but fused above base in female NMV A 25171 –002. Epichordal caudal-fin lobe well developed, separated by short interspace from and distinctly longer than second dorsal-fin base; hypochordal caudal lobe very low, originating near end of lateral fold, not confluent with epichordal lobe.

N. sapphira sp. nov. N. azurea

Holotype Paratypes Mean Holotype Paratypes Mean Min Max Min Max

Total length (mm) 360 342 413 621 230 540

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N. sapphira sp. nov. N. azurea Adult male holotype and female paratypes largely free of dermal denticles except along anterolateral margins of dorsal disc, between orbits, along mid-dorsal region of disc and on dorsal fins; a short, erect preorbital thorn on anterior upper rim of orbits. Male holotype with 6–9 alar thorns in 2 rows. Tail prickly with numerous thorns and thornlets on its dorsal surface; a vague mid-dorsal row of up to 45 small thorns (excluding additional surrounding thornlets); thorns with oval bases and recurved hook-like crowns. Ventral surface of disc and tail totally naked.

Claspers ( Figure 7 ) of adult male holotype long, very slender and flattened; glans only slightly expanded, tip bluntly pointed, with external components slit, cleft, pseudorhipidion, projection, spike and rhipidion.

Meristics (n=5): Tooth rows in upper jaw 31 (29–36); lower jaw 31 (28–32). Pectoral-fin propterygial radials 31 (31–32); mesopterygial radials 11 (10–13); metapterygial radials 27 (25–27); total radials 69 (67–70). Pelvic-fin radials in male holotype 1+19, 1+ 19–20 in females. Monospondylous trunk centra 24 (23–25); predorsal diplospondylous centra 71 (70–74); total predorsal centra 95 (95–99); interdorsal centra 8 (7–9); total diplospondylous centra 106 (101–109); total centra 130 (126–134).

Colour. When fresh, dorsal surface of disc uniformly rich blue, outer margins of disc narrowly dark edged; orbits and anterior pelvic-fin lobes dark greyish or blackish; tail greyish blue dorsally, lateral tail fold blackish; dorsal fins greyish blue with narrow dark edges. Ventral surface of disc, pelvic fins, and tail dark brown or brownish black, skin semi-translucent; outer margins of disc and pelvic fins broadly blackish; dark patches around each gill area, interbranchial region paler, dark brown; claspers dark brown, glans with some pale flecks; cloaca opening, mouth corners and posterior margin of posterior nasal lobe whitish. In preservative: Bright blue coloration fading (paler bluish in MNHN 1997-3591), becoming darker blue in other paratypes; dorsal surface appears to have irregular flecks, concentrated around bases of denticles and thornlets.

Size. Reaches at least 413 mm TL; smallest mature male 360 mm TL (holotype).

Distribution. Known only from the five type specimens collected on the slopes of the Norfolk Ridge (Coral Sea and Tasman Sea) from 25°41’S to 34°17’S ( Figure 8 ), and between 1195–1313 m depth.

Etymology. From the Greek sappheiros in reference to its intense blue dorsal coloration resembling that of a dark sapphire (gemstone). Vernacular names: Sapphire Skate (English), raie saphir (French).

Remarks. Among the seven nominal species of Notoraja , only N. sapphira has a primarily blue dorsal coloration similar to that of N. azurea from southern Australia (described from Tasmanian specimens). The two species are distinguished by the combination of the following characters: N. sapphira appears to have a smaller adult size than N. azurea (maximum known length 413 mm TL whilst N. azurea reaches at least 645 mm TL; size of the smallest mature male is 360 mm TL for N. sapphira and 535 mm TL for N. azurea ) and the snout is less attenuated in the adult male holotype of N. sapphira (90° versus 84-85° in N. azurea ); the disc width is slightly smaller in N. sapphira than in N. azurea (50.7–53.6% TL versus 52.6–57.0% TL); the interorbital distance is wider in N. sapphira than in N. azurea (3.6–4.1% TL versus 2.4–2.9% TL); the interspiracular distance is wider (6.0–6.6% TL versus 4.8–5.3% TL); the nasal curtain is wider in N. sapphira than in N. azurea (its minimum width is 6.6–7.0% TL versus 4.4–4.5% TL); the posterior nasal curtain lobe is more expanded in N. sapphira than in N. azurea (its width 2.2–2.5% TL versus 1.1–1.5% TL). Also, the distances between the first gill slits and the 5th gill slits are wider in N. sapphira than in N. azurea (11.7–12.8% TL versus 10.3–11.3% TL, and 7.2–9.2% TL versus 6.7–7.6% TL respectively), the base of the tail is proportionally wider and deeper in N. sapphira than in N. azurea (its width and height at pelvic axils are 1.2–1.3% TL versus 0.6–0.8% TL, and 0.6–0.8% TL versus 0.3–0.6% TL respectively). Furthermore, the dorsal surface of N. azurea is greyish blue and flecked with small darker spots, instead it is a plain rich blue coloration in N. sapphira . Beside the preorbital thorn present in both species, N. azurea has also a postorbital thorn. The thorn pattern of the tail is different between the two species ( Figure 6 ): in N. sapphira , it consists of thornlets and small thorns densely distributed dorsally all over the tail; in N. azurea , it consists of fewer, larger thorns that are arranged in more or less regular and more widely spaced rows. The numbers of vertebral centra are slightly different: diplospondylous predorsal centra 76–80 in N. azurea (70–74 in N. sapphira ), total number of predorsal centra 103–106 (95–99). N. sapphira has fewer tooth rows in the upper and lower jaws than N. azurea : 29–36 versus 32–43 and 28–32 versus 32–39 respectively ( Table 2).

In their description of N. azurea, McEachran & Last (2008) stated that its coloration varies geographically and that the specimens from New South Wales assigned to N. azurea are darker; therefore they based their description on Tasmanian specimens only in case more than a single species was involved. We compared six specimens of New South Wales to the types of N. azurea and could not find differences other than the extent of dark blue coloration.

Table 3 summarises the geographical distributions, maximum TL and depth ranges of the seven known species of Notoraja . Most of the species occur in Australian waters, except N. lira from southeastern Indian Ocean, N. tobitukai from Japan, and the new species N. sapphira which is known from off New Caledonia (Coral Sea) and New Zealand (Tasman Sea). All Notoraja species are relatively small-sized skates, the largest are N. azurea and N. sticta which reach 64.5 and 62.7 cm TL respectively; the new species N. sapphira is among the smallest with a maximum known TL of 41.3 cm, the smallest being N. ochroderma with a maximum TL of 37 cm. Notoraja species are deepwater skates, found between 300 m and 1440 m depth; N. ochroderma is found on the upper slope between 400 and 450 m depth, N. hirticauda occurs on the mid-upper slope (590–760 m depth), and N. azurea and the new species N. sapphira occur deeper on the mid-slope, reaching 1440 m and 1313 m depth respectively.

N. sapphira N. azurea N. azurea * 6 specimens Norfolk Ridge Tasmania NSW 5 specimens 6 specimens 3 specimens Monospondylous centra 23–25 25–27 25–26 Predorsal diplospondylous centra 70–74 76–80 74–78 Interdorsal diplospondylous centra 7–9 7–8 8–10 Total number of diplospondylous centra 101–109 108–111 109–112 Total number of centra 126–134 135–137 134–138 Pectoral-fin radials 67–70 66–69 66–70 Tooth rows upper jaw 29–36 32–43 36–42 Tooth rows lower jaw 28–32 32–39 34–43 Angle in front of spiracle 100°–104° 84°–112° 86°–101° * Species Geographical distribution Max. TL in cm Depth range in m N. azurea Southern Australia 64.5 765 – 1440 N. hirticauda Western Australia 44.8 590 – 760 N. lira Southeastern Indian Ocean 41.5 1050 N. ochroderma Northeastern Australia 37.0 400 – 450 N. sapphira Norfolk Ridge 41.3 1195 – 1313 N. sticta Great Australian Bight 62.7 820 – 1200 N. tobitukai Japan 50.0 300 – 1000

Figures

FIGURE 1. Notoraja sapphira sp. nov., male holotype (NMNZ P 39528, 360 mm TL, fresh): A, dorsal surface; B, ventral surface.

FIGURE 2. Notoraja sapphira sp. nov., female paratype (CSIRO H 6071 – 01, 342 mm TL, fresh): A, dorsal surface; B, ventral surface.

FIGURE 3. Dorsal view of head of Notoraja sapphira sp. nov., adult male holotype (NMNZ P 39528, 360 mm TL) showing snout, orbito-spiracular and nuchal regions.

FIGURE 4. Ventral view of Notoraja sapphira sp. nov. showing oronasal region and tooth band: A, adult male holotype (NMNZ P 39528, 360 mm TL); B, female paratype (CSIRO H 6071 – 01, 342 mm TL).

FIGURE 5. Lateral view of dorsal and caudal fins of Notoraja sapphira sp. nov., adult male holotype (NMNZ P 39528, 360 mm TL).

FIGURE 6. Thorns at tail midlength of Notoraja sapphira sp. nov.: A, dorsal and B, lateral views of adult male holotype (NMNZ P 39528, 360 mm TL); C, dorsal and D, lateral views of adult male holotype of N. azurea (CSIRO H 170 – 01, 621 mm TL).

FIGURE 7. Right clasper and its expanded glans of adult male holotype of Notoraja sapphira sp. nov. (NMNZ P 39528, 360 mm TL). cf: clef, pj: projection, pr: pseudorhipidion, rh: rhipidion, sl: slit, sp: spike.

FIGURE 8. Map of the southwestern Pacific Ocean showing the localities on the Norfolk Ridge where the five types of Notoraja sapphira sp. nov. were caught (black star: holotype, black circle: paratypes) and generalised localities (black ellipses) of N. azurea from Tasmania (TAS).