Squatina pseudocellata, Last, Peter R. & White, William T., 2008

Last, Peter R. & White, William T., 2008, Three new angel sharks (Chondrichthyes: Squatinidae) from the Indo-Australian region, Zootaxa 1734, pp. 1-26 : 16-25

Squatina pseudocellata new species

Western Angel Shark

Figs 6 , 7 , 8 c, Table 3 .

Squatina sp. B: Last and Stevens, 1994, Sharks and Rays of Australia, pp 277, 279, figs 31.2, pl. 38. Squatina tergocellata: Sainsbury, Kailola and Leyland, 1985 , Continental Shelf Fishes of Northern and North-Western Australia, pp 38, fig.

Squatina sp.: Allen, 1997, Marine Fishes of the Great Barrier Reef and South-East Asia, pp 46, 47, fig.

S. legnota n. sp. S. pseudocellata n. sp.

Paratypes (n = 5)

Holotype Paratype non-type Holotype Min. Max. to be continued...

S. legnota n. sp. S. pseudocellata n. sp. Paratypes (n = 5) Holotype Paratype non-type Holotype Min. Max. D1A – First dorsal-fin anterior margin 7.9 9.7 9.9 8.9 8.5 9.0 D1H – First dorsal-fin height 5.5 6.8 7.2 5.8 5.8 6.2 D 1I – First dorsal-fin inner margin 2.9 2.8 3.1 3.3 2.7 3.2 D2B – Second dorsal-fin base length 3.7 4.1 3.8 3.8 3.6 3.9 D2A – Second dorsal-fin anterior margin 8.1 9.2 9.9 8.3 8.1 9.0 D2H – Second dorsal-fin height 5.2 5.8 6.7 5.9 5.0 6.1 D 2I – Second dorsal-fin inner margin 2.6 2.7 3.1 3.0 2.6 3.3 CDM– Dorsal caudal-fin margin 12.9 15.2 15.8 11.7 11.6 12.8 CVM – Preventral caudal-fin margin 15.8 16.1 15.8 16.7 16.1 17.4 CAH – Caudal-fin height 14.3 17.0 17.8 14.0 14.1 15.8 CLI – Clasper inner length - 14.4 - 20.5 - - CLO – Clasper outer length - 5.9 5.4 7.4 - - CLB – Clasper base width - 2.7 2.8 2.6 - - Holotype. CSIRO H 2567–01, adult male 751 mm TL, west of Dorre Island, Western Australia, 25°09' S, 112°09' E, 312 m, 28 Jan. 1991.

Paratypes. 6 specimens. CSIRO CA 3291, immature male 412 mm TL, north of Port Hedland, Western Australia, 18°33' S, 118°20' E, 150 m, 28 Mar. 1982; CSIRO CA 3663, female 640 mm TL, northwest of Port Hedland, Western Australia, 19°01' S, 117°27' E, 142–144 m, 29 Jan. 1983; CSIRO CA 4474, immature male 568 mm TL, northwest of Port Hedland, Western Australia, 23 Nov. 1982; CSIRO H 4070–01, immature male 647 mm TL, northwest of Port Hedland, Western Australia, 18°12' S, 118°14' E, 266–269 m, 8 Sep. 1995; CSIRO H 5188–03, immature male 319 mm TL, north of Dampier Archipelago, Western Australia, 19°10' S, 116°19' E, 256 m, 27 Oct. 1998; WAM P 26195–001, female 376 mm TL, north of Dampier Archipelago, Western Australia, 19°10' S, 116°46' E, 175–178 m, 16 May. 1978.

Other material. CSIRO CA 292, immature male 491 mm TL, north of Dampier Archipelago, Western Australia, 19°17' S, 116°18' E, 170–172 m, 16 May 1978.

Diagnosis. A moderately small Squatina with the following characters: dorsal coloration complex, yellowish brown with small, greyish blue spots; faint brownish subdorsal saddles; anterior ventral surface of pectoral fin not black; single median row of enlarged scute-like denticles present on trunk; anterior nasal flap with strongly fringed barbels; upper lip forming a relatively narrow, strongly convex border with snout (lip arch width 2.6–4.0% TL, height 1.1–1.6% TL); interorbital region strongly concave; pectoral–pelvic space 11.7– 13.5% TL; pectoral-fin apex broadly rounded, much less than 120°; pelvic-fin free rear tips reaching or just beyond first dorsal-fin origin; tail relatively long, pelvic-fin origin to ventral caudal lobe 3.6–3.9 times pectoral-fin base; pectoral fins long, length 34.1–35.6% TL; dorsal fins not lobate; caudal fin of adult with bluntly pointed apices; monospondylous centra 46 or 47; total vertebral centra 130–135.

Description. Body strongly depressed anteriorly, firm; trunk strongly depressed, almost ray-like, deepest over abdomen; not tapering abruptly at pelvic-fin insertion, tail strongly depressed, even at origin of caudal fin. Abdomen moderately elongate, pectoral–pelvic space 13.3 (11.7–13.5)% TL, 0.89 (0.78–0.90) of prebranchial length; pelvic–caudal space 1.22 (1.11–1.27) times pelvic-fin length; tail relatively short, height at pelvic insertions 2.05 (2.00–2.27) in its width; caudal peduncle strongly depressed, short; lateral keels very well-developed, greatly expanded anteriorly, originating below insertion of second dorsal fin, well below lateral midline, extending well past middle of caudal fin; well-developed dorsal precaudal pit; pit absent ventrally.

Head broad, extended laterally, strongly depressed; oval in cross-section; subcircular, with truncate anterior margin when viewed from above (somewhat variable, truncate to weakly convex in paratypes); welldeveloped dermal folds present along ventrolateral margin of head, no lobes present near mouth corners; head width 18.7 (18.9–20.6)% TL, 3.25 (3.00–3.23) times head height. Snout very short, bluntly rounded in lateral view, horizontal preorbital length 3.5 (3.2–3.6)% TL; bulbous between nostril and eye; no obvious preorbital pit present; apex not indented anteriorly (sometimes slightly indented). Eye dorsolateral on head, small, slightly elevated, suboval, length 2.3 (2.2–2.9)% TL, 6.38 (5.59–6.75) in pre-branchial length; interorbit and midline of preorbital snout strongly concave; no subocular pouches; widely separated, interorbital space 3.47 (2.97–3.64) times eye length, 2.31 (2.31–2.56) times horizontal preorbital length, 0.94 (0.87–0.96) times direct prespiracular length, 4.47 (3.69–4.03) times spiracle length. Spiracle small, crescentic to elongate oval, slightly oblique, well separated from eye, subequal to eye; anterior margin strongly concave, barely elevated above flattened posterior margin; posterior margin almost flat to forming a slight depression leading into spiracle; greatest diameter 4.16 (3.41–4.16) in interspiracular space. Gill slits large, pleated, lateral on head, subequal in length, located well forward of midbase of pectoral fin, intergill distance 6.6 (6.6–7.3)% TL, 2.84 (2.68–2.87) in head width; posterior lateral head fold partly overlapping anterior tip of pectoral fin (in some paratypes not overlapping when head is twisted).

Mouth large, terminal (or very slightly inferior), horizontally expanded, broadly arched, terminating at mid-eye (slightly forward or at mid-eye in paratypes), width 12.1 (12.1–13.8)% TL, 1.54 (1.50–1.62) in head width, 1.50 (1.50–1.61) times interorbital space; upper lip forming a relatively narrow, strongly convex border with snout; upper labial furrows very large, forming deep preoral groove from symphysis to posterior of jaw angle; lower labial furrows elongate, deep, separated from each other by less than their length; shorter postoral groove very deep, extending parallel to lower labial furrow from jaw angle, length slightly greater than half lower labial furrow length. Teeth widely spaced, unicuspid, small, conical (dagger-like in smaller paratypes), without cusplets on a broad base; upper jaw with 3 small rows on each side of symphysis, midlateral teeth larger (about twice size of symphysial teeth) and more widely spaced than those adjacent; lower jaw edentate at symphysis, lateral teeth evenly spaced, slightly larger than those of upper jaw; no smaller, unpaired teeth at symphysis of upper jaw in holotype; teeth not protruding when mouth closed (1–3 pairs protruding in paratypes); teeth by row, in 4 paratypes, 16 in upper jaw, 14–16 in lower jaw.

Nostrils large, terminal on head, widely separated, internarial space 6.4 (6.2–6.9)% TL, 2.92 (2.97–3.34) in head width; adjacent upper lip of mouth. Anterior nasal flap large, overlapping mouth, with two well-developed, strongly fringed barbels; very large, basally flattened, posterolaterally directed barbel with a strongly fringed tip; distal fringes subequal in length to incurrent aperture of nostril; broad, strongly fringed membranous basal mesial lobe (partly concealed on inner basal edge of barbel and not distinct from posterolateral extension); central margin of flap with a long, thallate, moveable, strongly fringed barbel, directed ventrally, originating from a prominent, shallow pocket near border of flap; posteroventral margin of nostril with a variably developed, membranous flap, anterior margin weakly irregular, lateral margin somewhat filamentous; no nasoral or circumnarial grooves; no dermal lobes.

Dermal denticles covering entire dorsal surface of body; less dense, absent on posterior borders of fins (anterior apex of pectoral fins usually naked). Trunk denticles small, widely spaced, broadly subconical, strongly raked posteriorly; anterior bases with clearly defined anterior ridges; cusps bluntly pointed. Single enlarged, linear row of about 46 (in holotype) small, scute-like denticles along midline, originating just forward of pectoral-fin insertions and extending to first dorsal fin; denticles broad based, with pronounced radial ridges, their base widths more than 3 times base width of trunk denticles; with a short, blunt posteriorly directed cusp (more upright in smaller paratypes); separated from dorsal denticles by more than twice length of each denticle. Pre- and postorbit with greatly enlarged, spine-like denticles, much larger and more upright and strongly conical than those on dorsal midline of trunk and tail, more widely spaced than those above midorbit; slightly smaller enlarged denticles on postnarial snout. Adult male holotype with non-embedded, elevated, pungent, denticle patch extending from distal third of anterior pectoral fin around fin apex to just short of free rear tip, much larger than adjacent trunk denticles; pelvic fin with similar denticles along the outer anterior margin, extending posteriorly along posterior margin for about two thirds its length; absent in immature male paratypes; edge of pectoral and pelvic fin anterior margins with dense coverage of minute aspinous denticles (similar to those of ventral surface). Smallest paratype (CSIRO H 5188–03) with less welldeveloped trunk squamation, denticles in ill-defined linear rows, more or less evenly spaced; scute-like denticles with subcircular bases, prominent, bases almost abutting in row posteriorly; large scute-like denticles, paired at origin of each dorsal fin; enlarged denticles on head well developed, spinose, prominent, two postnasal denticles on each side of head, two to three on preorbit (posterior larger), triangular patch of three on postorbit (anterior larger); enlarged denticles becoming less distinct in larger paratypes. Ventral surface of body and fins largely naked (paratype CSIRO CA 3663 with a larger irregular patch on central abdomen); broad longitudinal band extending along almost entire length of anterior margin of pectoral fin, sharply demarcated from rest of fin but its mesial border irregular, greatest width about twice orbit diameter; similar but less extensive band around apex of pelvic fin, extending almost from fin origin to its free rear tip, broadest at fin apex (more restricted in smallest paratype); post-pelvic tail mostly covered with denticles, commencing at midline, well anterior of free rear tip of pelvic fins and extending to caudal fin (less well-developed in smallest paratypes); ventrolateral surfaces of tail with distinctly larger denticles than on rest of tail; denticles minute, densely packed, aspinous with smooth circular crowns with mostly entire margins, slightly more widely spaced near mesial border. Claspers of adult male holotype largely naked, most of outer half of ventral surface with minute denticles (immature male paratypes CSIRO CA 4474 and CSIRO H 4070–01 with an obvious development of denticles on ventral surface of clasper). Anterior half of dorsal fins with similar coverage of denticles to basal portions of pelvic and pectoral fins; similar denticles on most of caudal fin (smallest paratype with less well-developed denticle patches on dorsal and caudal fins).

Pectoral fins very large, expanded, base very fleshy, length 34.1 (34.9–35.6)% TL, 1.87 (1.83–1.97) times width; anterior margin almost straight to weakly convex, 1.59 (1.50–1.62) times inner margin; apex broadly rounded, angle much less than 120°; posterior margin slightly concave (more so in some paratypes); inner margin very strongly convex, free rear tip broadly rounded. Pelvic fins large, elongate, length 25.0 (22.7– 25.2)% TL, 1.36 (1.38–1.54) in pectoral-fin length; anterior margin strongly convex, apex broadly rounded; posterior margin weakly convex (almost straight in some paratypes); inner margin almost straight; free rear tip narrowly pointed, reaching origin of first dorsal fin (extending more posteriorly in most paratypes); pelvic-fin origin anterior to pectoral-fin free rear tip. Claspers of adult male slender, tapering, elongate, somewhat pointed and depressed distally, apex membranous, cartilage at glans opening not sharp-edged, outer margin 7.4% TL, 2.83 times base width. Dorsal fins similar in size and shape, strongly raked, close together, height of first 0.98 (0.99–1.24) times height of second; anterior margins straight to slightly convex; apices narrowly rounded to somewhat angular, well posterior to fin insertions; posterior margins weakly convex or almost straight, almost upright; inner margin weakly convex, free rear tip obtuse, broadly rounded; posteriorly located, interdorsal space 1.91 (1.69–1.94) times first dorsal-fin base, 1.25 (0.92–1.09) times dorsal–caudal space. Caudal fin hypocercal, short, dorsal caudal margin 11.7 (11.6–12.8)% TL, 2.61 (2.27–2.54) in pelvic– caudal space, height 14.0 (14.1–15.8)% TL; lower lobe much larger than upper lobe, preventral caudal margin 1.43 (1.35–1.40) times dorsal caudal margin; apices bluntly pointed (more rounded in juveniles); dorsal caudal margin almost weakly convex; preventral caudal margin strongly convex; postventral margin strongly notched, deepest slightly above its midlength.

Vertebral counts: monospondylous centra 47 (46 or 47, n=4); precaudal centra 103 (101–105); caudal centra 27 (28–30); total centra 130 (131–135).

Colour. In preservative: Dorsal surface yellowish brown, punctuated with dense coverage of small greyish blue spots (faint or obscure in some paratypes); edges of lateral keel pale yellowish; evidence of narrow, darker brown subdorsal saddles, extending onto bases of dorsal fins (barely distinguishable in some paratypes); irregular dark brownish blotch on caudal fin near its base; spiracles brownish; anterior nasal flap brownish basally, filaments pale. Spots densest on head, more or less uniformly spaced (not clustered), about a third to a fifth of eye length, diffuse edged; less well defined on dorsal, caudal and outer posterior margins of pectoral and pelvic fins; weak evidence of larger ocellate blotches on mid-base of pectoral fin, larger than eye; white post-interspiracular spot on midline of some paratypes, absent in holotype. Posterior margin of dorsal and caudal fins pale yellow to translucent, distinctly paler than rest of fin; pectoral and pelvic-fin margins pale yellowish.

Smallest paratype (CSIRO H 5188–03) with additional, large yellowish ocellate blotches; blotches much larger than eye, almost symmetrical, margins diffuse, partly distinguished by a rosette of smaller greyish blue spots. Ventral surface and sides of abdomen uniformly whitish; somewhat translucent along posterior margins of pectoral and pelvic fins, distinctly darker than rest of fin; scaled areas more yellowish than rest of ventral surface; mouth, lateral head fold and lips whitish. Clasper of adult male holotype almost uniformly pale, distal dorsal portion of glans dusky.

Size. Specimens examined ranged from 319 mm TL (smallest paratype) to 751 mm TL (adult male holotype). Males still immature at 647 mm TL.

Distribution. Endemic to tropical and subtropical Western Australia between Port Hedland (ca. 18° S) and Dorre Island (ca. 25° S); demersal on the outer continental shelf and upper slope in depths of 150– 312 m.

Etymology. The epithet is a combination of the Latin pseudo (meaning false) and ocellata (ocelli) referring to the indistinct ocellate markings on the pectoral fins.

Comparisons. Of the Australian species, S. pseudocellata is most similar to S. albipunctata in body shape. Squatina pseudocellata has a slightly narrower intergill width (6.6–7.3% vs. 7.4–8.2% TL in S. albipunctata ), shorter pectoral-fin base length (11.2–11.9% vs. 11.9–13.4% TL) and relatively longer pelvic (origin)–caudal space (42.1–45.2 (mean 43.2)% vs. 38.8–42.6 (mean 40.7)% TL). It also differs in two other ratios: head width 2.7–2.9 vs. 2.5–2.7 times intergill width; and preventral caudal-fin margin 1.3–1.4 vs. 1.4– 1.8 times dorsal caudal-fin margin.

Squatina pseudocellata differs from the material examined of S. tergocellata ( Fig. 10 ) in having a narrower intergill (width 6.6–7.3% vs. 7.3–8.1% TL), thicker tail (height 4.8–5.4% vs. 4.2–4.9% TL), longer pectoral–pelvic space (11.7–13.5% vs. 10.5–12.6% TL) and dorsal caudal-fin margin (length 11.6–12.8% vs. 10.1–11.2% TL), and a shorter pectoral-fin base (length 11.2–11.9% vs. 12.3–12.9% TL), pectoral-fin anterior margin (length 28.0–29.0% vs. 28.6–30.5% TL) and pelvic-fin (length 22.7–25.2% vs. 24.6–26.4% TL). They differ slightly in at least four other ratios: pectoral–pelvic space 0.8–0.9 in S. pseudocellata vs. 0.6–0.8 times prebranchial length in S. albipunctata ; head width 2.7–2.9 vs. 2.5–2.7 times intergill width; interdorsal space 1.7–1.9 vs. 1.3–1.7 times first dorsal-fin base length; and preventral caudal-fin margin 1.3–1.4 vs. 1.4–1.6 times dorsal caudal-fin margin.

Morphometrically, S. pseudocellata and S. australis ( Fig. 9 ) are very different from each other: preorbital length 3.2–3.6% TL in S. pseudocellata vs. 3.7–4.5% TL in S. australis ; prebranchial length 14.6–16.0% vs. 16.0–16.6% TL; interspiracular space 7.4–8.8% vs. 8.9–10.1% TL; head height 5.7–6.8% vs. 7.1–8.5% TL; intergill width 6.6–7.3% vs. 8.2–8.9% TL; pectoral–pelvic space 11.7–13.5% vs. 7.4–8.6% TL; pectoral-fin base length 11.2–11.9% vs. 13.0–13.9% TL; pectoral-fin length 34.1–35.6% vs. 31.3–33.8% TL; pectoral-fin inner margin 17.9–19.0% vs. 13.5–14.7% TL; pelvic-fin inner margin 8.8–10.9% vs. 8.0–8.5% TL; dorsal-caudal space 6.6–7.5% vs. 5.6–6.4% TL; preventral caudal-fin margin 16.1–17.4% vs. 17.7–19.1% TL; trunk width 15.5–17.3% vs. 18.6–20.4% TL; width at pectoral origins 14.2–16.3% vs. 16.6–18.2% TL; internarial space 6.2–6.9% vs. 6.9–7.4% TL; pectoral–pelvic space 0.8–0.9 vs. 0.5 times prebranchial length; head width 3.0–3.3 vs. 2.3–2.9 times its height; interorbital space 2.3–2.6 vs. 1.8–2.2 times preorbital length; interspiracular space 3.4–4.2 vs. 4.4–5.5 times spiracle length; head width 2.7–2.9 vs. 2.3–2.4 times intergill width; pectoral-fin anterior margin 1.5–1.6 vs. 1.9–2.2 times its inner margin; and preventral caudal-fin margin 1.3–1.4 vs. 1.6–1.7 times dorsal caudal-fin margin.

Squatina pseudocellata has more ornate nasal flaps and barbels than other angel sharks of the Indo-West Pacific, with the exception of S. tergocellatoides . According to Walsh and Ebert (2007), S. tergocellatoides lacks a median row of enlarged denticles whereas a row of scute-like denticles is present in S. pseudocellata .

Figures

FIGURE 6. Squatina pseudocellata sp. nov., holotype (CSIRO 2567 – 01, adult male 751 mm TL): A, dorsal view; and B, ventral view.

FIGURE 7. Illustration of the anterior nasal flap of holotype of Squatina pseudocellata sp. nov. (CSIRO 2567 – 01). Illustration by Stephanie Barnes.

FIGURE 8. Lateral view of the tail and ventral view of the caudal keel of: A, Squatina albipunctata sp. nov. holotype (CSIRO H 6561 – 01, adult male 985 mm TL); B, Squatina legnota sp. nov. paratype (CSIRO H 6565 – 01, adult male 1252 mm TL); and C, Squatina pseudocellata sp. nov. (CSIRO H 2567 – 01, adult male 751 mm TL).

FIGURE 9. Dorsal view of Squatina australis (CSIRO H 4255 – 02, female 970 mm TL).

FIGURE 10. Dorsal view of Squatina tergocellata (CSIRO H 2590 – 02, immature male 331 mm TL).

Tables

TABLE 3 Proportional dimensions as percentages of total length for the holotype (MZB 15500), paratype (CSIRO H 6565 – 01) and one non-type of Squatina legnota n. sp. and for the holotype (CSIRO H 2567 – 01) and ranges for the 5 paratypes of Squatina pseudocellata n. sp.

TL –– Total length	471	1252	1341	751	319 647
PCL – Precaudal length	85.4	83.9	83.7	85.5	84.1 85.6
PD1 – Predorsal length	61.6	62.3	60.9	63.9	62.3 64.7
PP2 – Prepelvic length	39.3	41.4	39.7	40.7	40.5 43.7
PP1 – Prepectoral length	19.8	18.3	19.1	19.3	19.1 21.4
PG1 – Prebranchial length	15.0	14.7	-	14.9	14.6 16.0
PSP – Prespiracular length	9.4	8.6	8.0	8.7	8.3 9.8
PEY – Pre-eye length	5.9	5.6	5.4	5.8	5.5 6.6
POB – Preorbital length	3.5	2.9	-	3.5	3.2 3.6
HDW – Head width	19.9	19.3	-	18.7	18.9 20.6
MOW – Mouth width	12.8	12.1	12.2	12.1	12.1 13.8
HDH – Head height	6.3	8.5	-	5.7	5.9 6.8
INO – Interorbital space	7.9	8.1	7.5	8.1	7.7 8.5
EYL – Eye length	2.4	1.8	1.8	2.3	2.2 2.9
INW – Internarial space	5.7	6.2	-	6.4	6.2 6.9
INS – Interspiracular space	7.8	7.6	7.0	7.5	7.4 8.8
SPL – Spiracle length	2.3	2.6	2.2	1.8	2.1 2.2
ING1 – Intergill width	7.4	8.6	-	6.6	6.6 7.3
ING – Intergill length	2.0	2.1	-	2.1	2.0 2.5
IDS – Interdorsal space	7.6	6.4	7.0	8.2	6.9 7.6
DCS – Dorsal–caudal space	9.0	8.1	8.0	6.6	6.8 7.5
PPS – Pectoral–pelvic space	9.4	10.9	-	13.3	11.7 13.5
POCS – Pelvic (origin)–caudal space	45.2	45.7	-	45.2	42.1 44.0
PCA – Pelvic–caudal space	32.0	31.3	-	30.6	27.9 29.4
WP1 – Width at pectoral origins	15.0	14.8	-	14.2	15.1 16.3
TRW – Trunk width	14.6	16.3	-	16.1	15.5 17.3
TAW – Tail width	9.7	10.9	11.8	10.3	10.3 11.8
TAH – Tail height	4.7	4.9	4.4	5.0	4.8 5.4
P1L – Pectoral-fin length	33.7	33.5	-	34.1	34.9 35.6
P1A – Pectoral-fin anterior margin	26.1	25.5	-	28.4	28.0 29.0
P1B – Pectoral-fin base length	11.3	11.9	10.8	11.5	11.2 11.9
P1W – Pectoral-fin width	18.1	19.0	18.7	18.2	18.1 19.0
P1I – Pectoral-fin inner margin	18.8	17.7	-	17.9	17.9 19.0
P2L – Pelvic-fin length	23.2	24.4	23.9	25.0	22.7 25.2
P2W – Pelvic-fin width	12.9	13.9	-	14.6	13.2 14.3
P2I – Pelvic-fin inner margin	9.2	11.0	11.6	10.8	8.8 10.9
D1B – First dorsal-fin base length	4.6	4.9	4.6	4.3	3.8 4.2