Zanobatus maculatus, Séret, Bernard, 2016

Séret, Bernard, 2016, Zanobatus maculatus, a new species of panray from the Gulf of Guinea, eastern central Atlantic (Elasmobranchii: Batoidea: Zanobatidae), Zootaxa 4161 (4), pp. 509-522 : 510-520

Zanobatus maculatus sp. nov.

English name: Maculate Panray French name: Raie maculée ( Figs. 1–10 , Table 1)

Zanobatus schoenleinii: Poll, 1949: 188 (partim); Poll, 1951: 105, fig. 52. Zanobatus sp. n.: Séret, 2016: 1366, fig. 1.

Holotype. MNHN 1990-467, male 302 mm TL, cruise TOGO 2, N.O. “André Nizery”, station 20, 9th June 1983, 6°07’N, 13°50’E (Togo), 34 m depth, Picard bottom trawl, bottom temperature 27.2°C, salinity 35.3 %, col. B. Séret.

Paratypes (11 specimens). MNHN 1967-735 , male mature 297 mm TL and male juvenile 229 mm TL, Benin, col. Marteau, July 1964 ; MNHN 1989-1291 , male 290 mm TL, Togo, R/ V Nizery, station 20, 20 September 1983 ; MNHN 1989-1292, female 141mm TL, MNHN 1989-1293 , male 255 mm TL, and MNHN 1989-1519 , male 273 mm TL, Togo, R/ V Nizery, station 20, 20 September 1983 ; MNHN 1989-1525 , female 358 mm TL, and MNHN 1989-1537 , female 332 mm TL, Ivory Coast, cruise CHALCI, station 27, 14 January 1983 ; MNHN 1989-1524 , female 164 mm TL, Ivory Coast, col. T. Roberts, February 1986 ; MNHN 2015-63 , female, 311 mm TL and MNHN 2015-64 , male adult, 340 mm TL, Gulf of Guinea , 26th April 1990, col. Instituto Espanol de Oceanografia.

Other specimens. MNHN 1969-210 , males 176 and 335 mm TL, Ghana, 25th February 1964, Guinea Trawling Survey, Station tr32/st1a ; MNHN 1969-226 , male 330 mm TL, Guinean Trawling Survey, between Abidjan and Pointe Noire , 1964 ; MNHN 1969-236 , male 296 mm TL, Guinea Trawling Survey, station 67, 5°40’N, ° 0°12’E, Ghana, 25th September 1963 ; IRSNB 11553 /6920, male 352 mm TL, 14th cruise of R.V. Mercator, Santa-Maria Bay , Angola, 19th February 1938 ; IRSNB 16808 /8529, female 372 mm TL, R.V. Mbizi, station 141, 0°53’S, 8°40’E, SW of Cape Lopez , Gabon, 8th March 1949 .

Diagnosis. The new species is distinguished from its unique congener Zanobatus schoenleinii by the following set of characters: dorsal surface of disc brownish to reddish brown, with numerous dark brown blotches, sometimes surrounded by a network of whitish dots; ventral surface of disc pale creamy white or orange-brown, with conspicuous dark brown posterolateral margins; crown of dermal denticles of dorsal surface spearhead-shaped; enlarged thorny denticles of the dorsal surface more numerous and stronger, in parallel rows on trunk and in concentric semi-circular rows on pectoral fins; 54–64 tooth rows in upper jaw; 36–44 (mode 39) predorsal vertebrae; maximum size 359 mm TL.

Description. Table 1 gives measurements expressed as proportions of total length for the holotype and paratypes. A small panray (maximum TL 358 mm), with sub-circular disc, its width slightly greater than its length (53–61% TL vs. 48.1–55.3% TL); disc rather thick; snout short and obtuse, preorbital length 11.5–13.7% TL; anterior margin evenly convex, outer pectoral apex and inner pectoral corners broadly rounded; tail robust, slightly longer than trunk, tail length 49.6–52.0 % TL vs. distance from snout to cloaca 42.3–47.6 % TL, semi-circular in cross section, tapering backward; a low, inconspicuous longitudinal keel along the posterolateral margin of tail; pelvic fins wide, triangular with broadly rounded apex; dorsal fins triangular with rounded apex, first dorsal larger fin than second dorsal; caudal fin rather small, fan-shaped, with no distinct ventral lobe.

Eyes large, length about 2.7–3.0 times in preorbital length, and 1.1–1.2 in interorbital space. Spiracle about as large as eyes, respective length 4.2–6.0% TL vs. 3.3–5.7% TL. Nostril rather short, oblique, anterior nasal valve bilobed, outer lobe long, finger-like, inner lobe as a low fold, well extending onto internasal space, distance between inner lobes of anterior nasal flaps short but distinct; posterior nasal flap well developed and flared, with an outer rounded lobe and a ribbon-like narrow inner lobe. Mouth small, almost straight, with thick lips; a fleshly knob-like process at level of mid-upper lip. Teeth small, in quincunx, forming a pavement of 54–64 rows (mean 59, n=11) in the upper jaw; teeth similar on both jaws; crown diamond-shaped with rounded margins and blunt cusps; cusps slightly more acute in mature males.

Skin thick and silky. In juveniles, dermal denticles of dorsal surface are spaced, longer than wide, with crowns spearhead-shaped with medial keels on each side of a deep median groove, fusing posteriorly to form acute cusps, lateral corners broadly rounded and wing-like. In adult, dermal denticles of dorsal surface are closely-set, almost as long as wide, with crowns spearhead-shaped but shorter with blunt cusps, and additional lateral keels, often limited to the anterior part of the crown. Dermal denticles of the ventral surface densely closely-set, slightly overlapping, forming a continuous pavement; the crows are more or less polygonal, flat and smooth, without any micro-reliefs (keels, grooves).

Enlarged thorny denticles of the dorsal surface with their base embedded in slender tubercles, their cusps blunt and slightly tilted backward; 22–32 enlarged thorny denticles in mediodorsal row from nape to first dorsal-fin origin; 1–4 between the dorsal fins; irregular parallel rows on trunk gradually disappearing posteriorly; concentric semi-circular rows on pectoral fins; stronger horny denticles on shoulders and over propterygium, mesopterygium and metapteryum; a few thornlets more or less embedded in skin on snout tip and in front of orbits.

Total number of pectoral radials 157–173 (mean 162, n=11) with 38–39 propterygial, 24–27 mesopterygial, and 16–16 metapterugial radials. Total number of vertebral centra (including synarcual segments) 129–146 (mean 138, n=11) with number of predorsal vertebra 37–44 (mean 40, n=11).

Colour. Dorsal surface brownish to reddish or greenish brown, maculated with numerous dark brown rounded blotches of various sizes, roughly forming concentric rows, sometimes surrounded by a network of small white dots; faint dark brown crossbars present on head and trunk, more conspicuous on tail; pelvic, dorsal and caudal fins also mottled with brown and light markings. Ventral surface pale creamy white with conspicuous dark brown posterolateral margins, mottled with darker blotches; sometimes a few irregular dark blotches scattered on belly. Nasal flaps and lips darker, often orange-yellow. Ventral surface of tail also pale creamy white with or without some dark mottling. Some specimens exhibit a dark reddish brown ventral coloration ( Fig.10 ) with darker oronasal area.

Zanobatus maculatus sp. nov. Z. schoenleinii

Holotype 9 paratypes 15 specimens

MNHN 1990-467 Mean Min Max Min Max male

Total length 302 mm 141 mm 358 mm 142 mm 554 mm

Disc wiđth 59.0 57.4 53.0 61.0 55.1 64.5

Disc length 53.8 51.3 48.1 55.3 47.3 56.5

Snout to maximum đisc wiđth 32.8 29.2 26.4 33.3 24.6 33.2

Preorbital snout length 13.4 12.6 11.5 13.7 10.0 16.1

Préoral snout length 15.5 14.8 13.3 16.5 11.1 18.3

Prenasal snout negth 11.7 11.5 10.6 13.5 10.2 14.5

Heađ length ventral 29.7 28.6 25.4 29.8 24.1 31.2

Distance snout tip to cloaca 47.2 45.2 42.3 47.6 42.4 50.2

Cloaca length 2.8 3.1 2.1 4.5 2.0 3.5

Distance cloaca to tail tip 51.4 50.9 49.6 52.7 48.9 53.8

Distance snout tip to pectoral-fin axil 49.0 46.9 45.4 48.8 39.2 51.9

Distance snout tip to pelvic-fin origin 45.9 43.8 41.2 46.1 44.5 49.1

Distance snout tip to D1 origin 71.0 69.0 65.9 70.9 63.4 74.6

Distance snout tip to D2 origin 81.7 79.4 76.9 81.4 73.9 86.3

Distance snout tip to cauđal-fin origin 90.0 88.1 85.4 93.6 82.2 93.8

Distance eye post. margin to pectotal-fin axil 32.8 31.1 30.0 31.7 26.8 33.2

Eye length 4.8 4.4 3.3 5.7 3.4 5.6

Spiracle length 5.2 4.9 4.2 6.0 3.9 6.3

Distance eye + spiracle 7.2 6.8 5.8 7.9 5.6 7.5 1 base length 6.6 6.1 5.4 6.4 4.3 8.5 1 anterior margin length 10.3 9.5 8.0 11.3 7.1 10.9 1 height 9.0 6.6 5.5 7.8 5.3 7.6

……continued on the next page Zanobatus maculatus sp. nov. Z. schoenleinii

Holotype 9 paratypes 15 specimens

MNHN 1990-467 Mean Min Max Min Max

male

1 posterior margin length 2.8 2.2 1.5 2.8 1.6 2.8 Interđorsal space 4.5 4.8 4.3 5.5 3.8 7.6

2 base length 6.6 6.1 5.4 6.7 4.8 6.2

2 anterior margin length 10.3 9.9 7.7 11.6 8.5 10.9

2 height 8.6 7.3 5.2 7.8 2.2 7.1

2 posterior margin length 3.1 2.4 1.7 3.9 1.3 16.9 Distance D2 to cauđal-fin origin 1.4 2.2 1.4 3.2 1.0 4.2 Cauđal-fin anterior margin length 12.8 12.4 10.9 16.5 8.7 16.9 Pelvic-fin anterior margin length 10.7 10.9 10.0 11.5 7.9 10.8 Pelvic fin length 16.6 15.5 14.0 16.7 13.0 17.1 Interorbital space 4.1 4.2 3.7 5.7 2.6 4.8 Interspiracuar space 7.6 7.4 6.4 8.5 5.9 8.2 Internasal space 5.2 4.9 4.1 5.7 4.0 5.6 Mouth wiđth 6.9 6.5 6.1 7.2 5.5 8.2

gill-slit length 1.7 1.6 1.2 1.8 1.4 2.1

gill-slit length 1.7 1.6 1.2 1.8 1.6 2.2

gill-slit length 1.0 1.2 1.0 1.5 0.8 1.7 Distance between 1st gill slits 14.8 14.4 13.5 15.9 13.6 17.1 Distance between 5th gill slits 9.0 8.8 8.3 9.8 7.7 10.0

Size. The largest female is 358 mm TL; the holotype is an adult male of 302 mm TL.

Distribution. Mostly in the Gulf of Guinea, from Ivory Coast to Gabon, with two records from Angola, on the inner continental shelf, from shore to about 30 m in depth, mostly on sandy bottoms.

Etymology. Derived from the Latin macula (spotted) with reference to its blotched colour pattern.

Comparisons (Figs. 11,12). The maculate panray Z. maculatus sp. nov. is distinguishable from its unique congener the striped panray Z. schoenleinii by the following features: the maculate panray is smaller than the striped panray (TL max 358 vs. at lest 600 mm); its disc more is rounded vs. somewhat rhombic in the striped panray; it has numerous dark brown blotches of various sizes vs. wavy medium brown crossbars; its dermal armature is more pronounced, and has spear-shaped dermal denticles vs. polygonal flat denticles in the striped panray, and smaller number of tooth rows, possibly due to its smaller size.

Remarks on the variant pattern of colouration in Mauritanian material. Among the specimens collected from Mauritania, several specimens of striped panray exhibit an albino-like pattern ( Fig. 13 ) with a pale yellowish background mottled with greenish markings and cloudy rusty blotches. The particular hydroclimatic conditions in this area might offer to some variant species a refuge to survive and even to develop (cf. Séret & Naylor, 2106).

Comparative material. Zanobatus schoenleinii (the morphometrics of all the following specimens were taken, and most were radiographed for meristic counts): MNHN 1989-1294 , female 143 and male 145 mm TL, Senegal ; MNHN 1989-1517 , female 262 mm TL, Senegal ; MNHN 1989-1518 , male 344 mm TL, Senegal ; MNHN 1989-1520 , female 490 mm TL, Mauritania ; MNHN 1989-1522 , female 319 mm TL, Senegal ; MNHN 1989-1523 , female 254vmm TL, Senegal ; MNHN 1989-1526 , female 454 mm TL, Senegal ; MNHN 1989-1527 , male 430 mm TL, Mauritania ; MNHN 1989-1528 , male 329, Mauritania ; MNHN 1989-1529 , male 398, Senegal ; MNHN 1989- 1530 , male 453 mm TL, Mauritania ; MNHN 1989-1531 , male 484 mm TL, Mauritania , MNHN 1989-1532 , male 466 mm TL, Senegal ; MNHN 1989-1533 , male 473 mm TL, Senegal ; MNHN 1989-1534 , female 457 mm TL, Senegal ; MNHN 1989-1535, female 326 mm TL; MNHN 1990-468 , female 186 mm TL, Senegal ; MNHN 1990- 469 , female 302, Senegal ; MNHN 1990-470 , male 315 mm TL, Senegal ; MNHN 1990-471 , female 350 mm TL, Senegal ; MNHN 1990-472 , male 242, Senegal ; MNHN 1992-23 , male 448 mm TL, Senegal : MNHN 1992-24 , male 384 mm TL, Senegal ; MNHN 1994-602 , female 336, Mauritania ; MNHN 1994-604 , male 554 mm TL, Mauritania .

Figures

FIGURE 1. Zanobatus maculatus sp. nov., holotype, MNHN 1990 - 467, male 302 mm TL, dorsal view.

FIGURE 2. Zanobatus maculatus sp. nov., holotype, MNHN 1990 - 467, male 302 mm TL, ventral view.

FIGURE 3. Zanobatus maculatus sp. nov., holotype, MNHN 1990 - 467, male 302 mm TL, oronasal area.

FIGURE 4. Zanobatus maculatus sp. nov., paratype, MNHN 1989 - 1525, female 359 mm TL, dorsal view.

FIGURE 5. Zanobatus maculatus sp. nov., paratype, MNHN 1989 - 1525, female 359 mm TL, ventral view.

FIGURE 6. Dermal denticles of Zanobatus maculatus sp. nov., MNHN 1989 - 1524, female 167 mm TL from Ivory Coast. A: x 300; B: x 125; MNHN 1990 - 467, holotype, male 302 mm TM from Togo; C: x 30, D: x 125, dermal denticles of Zanobatus schoenleinii, MNHN 1989 - 1534, female, 459 mm TL from Senegal; E: x 125, F: x 30.

FIGURE 10. Zanobatus maculatus sp. nov., freshly caught specimen, female 340 mm TL (not preserved) from Ivory Coast, with orange brown ventral coloration.

FIGURE 13. Zanobatus schoenleinii, MNHN 1989 - 1530, male 453 mm TL, albino specimen from Mauritania.