Apristurus platyrhynchus (Tanaka, 1909)

Nakaya, Kazuhiro & Kawauchi, Junro, 2013, A review of the genus Apristurus (Chondrichthyes: Carcharhiniformes: Scyliorhinidae) from Taiwanese waters, Zootaxa 3752 (1), pp. 130-171 : 161-168

Apristurus platyrhynchus (Tanaka, 1909)

English name: Spatula-snout catshark Taiwanese name: Bien-wen-bi-sa Japanese name: Herazame

( Figures 31–36 , Table 5 )

Scyliorhinus platyrhynchus Tanaka, 1909: 4 –6 (original description, type locality: Japan); Jordan et al., 1913: 10.

Apristurus platyrhynchus: Garman, 1913: 98 (description, Japan); Nakaya, 1975: 28, fig. 12 (description, Japan); Springer, 1979: 26 (description, Japan); Compagno, 1984: 278–279 (description, Japan); Nakaya in Masuda et al., 1984: 4, pl. 335- B (description, Japan); Nakaya, 1989: 201, fig. 2 (comparative material); Nakaya & Sato, 1999: 316 (taxonomic comments); Nakaya & Séret, 1999: 307 (comparative materials); Nakaya & Sato, 2000: 224 (description, Japan, China, Philippines, and Indonesia; figs 1–2; Yoshino & Aonuma, 2002: 130 (key to species, Japan); Compagno et al., 2005: 198, pl. 32 (description, Japan, Philippines and Australia); Kawauchi et al., 2008: 75, figs 1, 3, 6 (description, Japan, East China Sea, Philippines, South China Sea, and Australia); Last & Stevens, 2009: 194, fig. 25, 31.7 (description, Japan, Philippines and Australia); Ebert et al., 2013: 297, pl. 38 (description).

Apristurus macrorhynchus: Chen, 1963: 33 , fig. 11 (description, Taiwan).

Pentanchus verweyi Fowler, 1934: 237 , fig. 2 (original description, type locality: Indonesia); Fowler, 1941: 57 (key to species and description, Japan).

Apristurus verweyi: Compagno, 1984: 287 (description, Indonesia); Compagno, 1988: 170 (description, Indonesia); Compagno, 1999: 478.

Pentanchus platyrhynchus: Fowler, 1941: 57 (in part), not fig. 5 (description, Philippines).

Apristurus acanutus Chu, Meng & Li in Meng, Chu & Li, 1985: 46, fig. 3 (original description; type locality: China); Nakaya & Sato, 1999: 316 (description, China).

Apristurus sp. B: Last & Stevens, 1994: 169, 174, key fig. 24, pl. 19 (description, Australia).

Material examined. Taiwan: ASIZP 66206, male, 645 mm TL, South China Sea, 20°84’N, 117°45’E, 731 m. Other regions (type specimens): SCSFRI D-0172 (holotype of Apristurus acanutus ), female, 522 mm TL, estuary off Pearl river, South China Sea, 594 m depth. SFU D-0161 (paratype of A. acanutus ), 520 mm TL, South China Sea. USNM 93135 (holotype of Apristurus verweyi ), male, 303.0 mm TL, Sibuko Bay, Borneo. Other regions (non-types): BSKU 22337, female, 345 mm TL, Kochi Prefecture, Japan. BSKU 22788, female, 355 mm TL, Tosa Bay, 960–985 m depth. BSKU 26866, male, 347 mm TL, 750–760 m depth, BSKU 27062, female, 499 mm TL, BSKU 27063, male, 415 mm TL, BSKU 27064, male, 425 mm TL, BSKU 27065, female, 418 mm TL, 650 m depth, BSKU 27594, male, 423 mm TL, BSKU 27597, male, 377 mm TL, 610–640 m depth, BSKU 33521, female, 473 mm TL, BSKU 33522, female, 435 mm TL, BSKU 33523, female, 380 mm TL, BSKU 33524, male, 380 mm TL, BSKU 33525, male, 347 mm TL, 780-810 m depth, BSKU 33972, female, 280 mm TL, 700–715 m depth, HUMZ 103699, female, 528 mm TL, Okinawa Trough, Japan. HUMZ 103700, male, 484 mm TL, Kumano- Nada, Mie Prefecture, Japan. HUMZ 105984, male, 438 mm TL, HUMZ 105985, male, 445 mm TL, locality unknown. HUMZ 145155, female, 455 mm TL, HUMZ 145156, female, 407 mm TL, HUMZ 145162, female, 337.5 mm TL, HUMZ 145163, female, 303.8 mm TL, HUMZ 145169, female, 478 mm TL, HUMZ 145157, female, 402 mm TL, HUMZ 145158, male, 478 mm TL, HUMZ 145159, female, 422 mm TL, HUMZ 145160, female, 403 mm TL, HUMZ 145170, female, 591.9 mm TL, Okinawa Trough, Japan. HUMZ 191332, male, 490 mm TL, off Sumatra Island, Indonesia, 960- 760m depth. FRLM 27652, male, 692 mm TL, Kumano-nada, Mie Pref., Japan. TMFE 21, female, 645 mm TL, TMFE 22, female, 680 mm TL, TMFE 23, female, 651 mm TL, Suruga Bay, Shizuoka Prefecture, Japan. TMFE 40, male, 536 mm TL, Suruga Bay, off Hagachi Cape, Shizuoka Prefecture, Japan, 675–720 m depth. TMFE 286, female, 609 mm TL, TMFE 287, female, 630 mm TL off Heta, Shizuoka Prefecture, Japan, 625–750 m depth. TMFE 520, male, 739 mm TL, locality unknown. TMFE 591, male, 602 mm TL, TMFE 592, female, 617 mm TL, off Omaezaki, Shizuoka Prefecture, Japan, 400–600 m depth. ZUMT 3424, female, 654 mm TL, locality unknown. AMS I 20068-016, male, 408 mm TL, east of Broken Bay, New South Wales, Australia, 886–895 m depth. AMS I 20920-020, female, 285 mm TL, north-east of Raine Island, Queensland, Australia, 900 m depth. AMS I 21724-018, male, 708 mm TL, east of Broken Bay, New South Wales, Australia, 1005 m depth. AMS I 24101-005, male, 604 mm TL, off Sydney, New South Wales, Australia, 830 m depth. AMS I 24356-008, female, 552 mm TL, off Shoalhaven Bight, New South Wales, Australia, 1043–1061 m depth. CSIRO H 913-01, male, 666 mm TL, east of Sugarloaf Point, New South Wales, Australia, 905–960 m depth. CSIRO H 1201-02, female, 426 mm TL, Houtman Albrolhos Islands, Western Australia, Australia, 880 m depth. CSIRO H 1280-07, female, 512 mm TL, east of Nowra, New South Wales, Australia, 981–990 m depth. CSIRO H 1286-03, female, 548 mm TL, Marian Plateau, northeast of Whitsunday Group, Queensland, Australia, 1005–1013 m depth. CSIRO H 1343-01, male, 669 mm TL, east of Nowra, New South Wales, Australia, 891– 909 m. CSIRO H 1537-02, female, 416 mm TL, east of Brush Island, New South Wales, Australia, 930–950 m depth. CSIRO H 1543-01, female, 507 mm TL, east of Brush Island, New South Wales, Australia, 890–910 m depth. CSIRO H 2265-02, male, 695 mm TL, west of Geraldton, Western Australia, Australia, 960 m depth, 29 Jan 1989. CSIRO H 2336-01, male, 682 mm TL, CSIRO H 2336-02, female, 553 mm TL, CSIRO H 2336-03, male, 508 mm TL, CSIRO H 2336-04, female, 430 mm TL, east of Tuncurry, New South Wales, Australia, 1025–1080 m depth. CSIRO H 2337-01, female, 529 mm TL, east of Nowra, New South Wales, Australia, 995–1050 m depth. CSIRO H 2500-01, male, 568 mm TL, east of Broken Bay, New South Wales, Australia, 1037–1049 m. FSFL ED 308, male, 525 mm TL, Norfolk Ridge, Australia, 885 m depth.

A. platyrhynchus

Taiwan Other regions (types of junior synonyms) 1 male 37 males, 46 females (1 male, 2 females) A. platyrhynchus

Taiwan Other regions (types of junior synonyms)

1 male 37 males, 46 females (1 male, 2 females)

Caudal length 31.1 29.0–33.5 (31.2–31.9) Clasper outer length 4.7 1.1–5.7 (1.8) Counts

Tooth rows:

upper 69 60–86 (67–74)

lower 74 57–87 (73–85) Vertebrae:

monospondylous 37 33–40 (35)

precaudal diplospondylous 42 37–45 (―) Spiral valves ― 16–20 (17–18)

Diagnosis. A species of Apristurus with the following characters: upper labial furrows much longer than the lowers; first dorsal fin much smaller than second dorsal fin, originating above middle of P2–anal space; second dorsal-fin insertion well anterior to anal-fin insertion; snout rather long, tip bell-shaped; abdomen very short; P1– P2 space shorter than three fifths of anal-fin base length (ceratotrichia); pectoral-fin tip always extending beyond midpoint of P1–P2 space; intestinal spiral valves 16–20; monospondylous + precaudal diplospondylous vertebrae 33–40 + 37–45; clasper hook absent on edge of exorhipidion; body uniformly light blown or grey to dark blown; maturing size larger than 55 cm TL in both sex.

Description. Proportional measurements and meristic counts are given in Table 5 . Body cylindrical, slender and elongate ( Figure 31 ). Head dorso-ventrally flattened, posterior part of body compressed laterally. Snout rather long; tip bell-shaped. Pre-outer nostril length slightly greater than internarial width. Pre-oral length slightly less than preorbital length, 2.2–2.9 times internarial width, slightly greater than mouth width and greater than interorbital width. Pre-orbital length 1.3–2.1 times of interorbital length, 2.4–4.3 times orbit length. Internarial width subequal to orbit and nostril width. Nostril expanding obliquely inward from snout edge; length about half of pre-inner nostril length. Nostril–mouth space about half of internarial width. Mouth widely arched, with well developed labial furrows; upper labial furrows 1.3–1.8 times longer than lower one. Upper labial furrow reaching beyond midpoint between mouth corner and posterior margin of nostril. Orbit narrow and slender, with a weak subocular fold. Spiracle very small placed slightly below level of horizontal axis of orbit. Five small gill slits present; third gill slit above pectoral-fin origin; fifth gill slit smallest, above pectoral fin base. Gill septa with projection, covered closely with dermal denticles. Abdomen very short; P1–P2 space shorter than three fifths of anal-fin base length (ceratotrichia); pectoral-fin tip always reaching beyond midpoint of P1–P2 space. Pectoral fin large, wide, triangular; outer margin not parallel to inner margin. Pelvic fin moderate in size, its length equal to pre-orbital length. Dorsal fins different in shape; first dorsal fin much lower and narrower than second one. First dorsal fin origin above middle of P2–anal space; insertion posterior to anal-fin origin. Second dorsal-fin origin slightly behind middle of anal-fin base; insertion anterior to anal-fin insertion. Anal fin low, triangular, with a base much longer than P1–P2 space; apex clearly posterior to first dorsal-fin insertion; posterior margin straight; anal and caudal fins separated only by a notch. Caudal fin slender; ventral lobe a little produced: apex of ventral lobe rather angular; subterminal notch distinct; length of terminal lobe moderate ca. 1.8 times caudal terminal lobe height. Caudal peduncle height ca. 0.7–1.4 times pre-outer nostril length. Duodenum very short.

Intestinal spiral valves 16–20. Monospondylous vertebrae 33–40; precaudal diplospondylous vertebrae 37–45.

Teeth numerous and small, 60–86 rows on upper jaw, 57–87 rows on lower jaw with one long central cusp and one to two short lateral cusps; one to two short sharp lateral cusps on upper teeth and one short and one minute lateral cusps on lower jaw teeth.

Egg capsule taken from 651 mm TL specimen (TMFE 23) ( Figure 32 ) very slender and long, 94.5 mm in length and 21.8 mm in width, without coiled tendrils on anterior and posterior ends; anterior margin of the capsule rounded without projection at each corner; lateral edges flanged, fused at posterior end; posterior tip forming narrow tapering tube. Surface of egg capsule with ridges. Color dark to reddish brown.

Dermal denticles from dorso-lateral side of body small ( Figure 33 ), overlapping each other, tricuspid, with a long ridged central cusp and shorter lateral cusps; outer surface of denticles completely structured by reticulations. No modified dermal denticles on the dorsal margin of the caudal fin. Dermal denticles densely present around the gill slits and on gill septa.

Clasper stout at base, tapering posteriorly ( Figure 34 ). Ventral and outer side of surface covered with dermal denticles. Dorsal side of clasper naked and ventral and lateral sides covered with clasper denticles; clasper hooks absent; pseudosiphon slit-like in shape and deep; cover rhipidion vestigial; pseudopera not distinctively long; exorhipidion flat and simple in shape, with free posterior end.

Color. Upper and lower surfaces of body and fins uniformly light brown or grey to dark brown with blackish naked areas along the fin margins. Tongue and palate light brown.

Size. Maximum size 800 mm TL in male (holotype), and 669.5 mm TL in female ( Figure 35 ). Most males less than 525.5 mm TL in maturity stage 1 (immature) with short claspers, less than 2.1% TL. One male of 568 mm TL in maturity stage 2 (adolescent) with developing, but soft claspers. All males more than 592.1 mm TL in maturity stage 3 (adult) with long, well developed and hardened claspers. All females less than 548 mm TL in maturity stage 1. One female in 553 mm TL in maturity stage 2. All females more than 591.9 mm TL in maturity stage 3.

Distribution. Japan (northward to Suruga Bay), East China Sea (Okinawa Trough), Taiwan, Philippines, South China Sea, Indonesia, Australia ( Norfolk Ridge, Queensland, New South Wales and Western Australia) and New Caledonia ( Figure 36 ), at depths of 400–1080 m.

Remarks. Apristurus platyrhynchus was originally described by Tanaka (1909) based on a mature male collected from Suruga Bay, Japan. This species belongs to the ‘brunneus group’ (sensu Nakaya & Sato, 1999) of the genus Apristurus , characterized by having considerably longer labial furrows on the upper jaw than those on the lower jaw, and a greater number of spiral valves in the intestine.

Since the original description of the species, no one worked on it until Nakaya (1975) made a taxonomic revision of Japanese scyliorhinid sharks. Later, Nakaya & Sato (2000) worked on A. platyrhynchus and its five related species, and synonymized both A. verweyi (Fowler, 1934) from the Philippines and A. acanutus Chu, Meng & Li, 1985 from the South China Sea with A. platyrhynchus . Recently, Kawauchi et al. (2008) further examined the specimens from Indonesia and Australia, and suggested that this species is widespread in Japan, Philippines, Indonesia, and even Australia.

Among the species of Taiwan, Apristurus platyrhynchus resembles A. macrostomus in having a rather long snout, and a narrower interspace between the pectoral and pelvic fin bases, butit is distinguishable by a more posterior position of first dorsal fin, a higher second dorsal fin, the absence of hooks on the clasper, larger sizes at maturity, and larger maximum size (see A. macrostomus for detailed discussion).

Apristurus platyrhynchus was reported from Taiwan by Shen & Wu (2011), but this record refers to A. macrostomus , and A. platyrhynchus has not been correctly reported from Taiwan before. The specimen used here (ASIZP 66206) was collected from the southwestern waters of Taiwan, and this is the first reliable report of this species based on a voucher specimen.

Figures

FIGURE 31. Apristurus platyrhynchus. A – C, ASIZP 66206, male, 645 mm TL, South China Sea; D, Drawing from Nakaya (1975).

FIGURE 32. Egg capsule of Apristurus platyrhynchus from TMFE 23, female, 651 mm TL. Scale bar = 1 cm.

FIGURE 33. Dermal denticles of Apristurus platyrhynchus, TMFE 520, male, 711 mm TL. Scale bar = 0.5 mm.

FIGURE 34. Dorsal view of left clasper of Apristurus platyrhynchus, TMFE 520, male, 711 mm TL. CD, clasper denticles; ER, exorhipidion; PP, pseudopera; PS, pseudosiphon; PV, pelvic fin; RH, rhipidion. Scale bar = 1 cm.

FIGURE 35. Maturity stages of Apristurus platyrhynchus. Open symbols, males; solid symbols, females.

FIGURE 36. Distribution of Apristurus platyrhynchus.

Tables

TABLE 5. Proportional measurements and counts of Apristurus platyrhynchus.

TL (mm)	645	280–739 (303–522)
Proportion (%TL)
PreD2-origin length	60.5	56.6–68.0 (60.1–68.0)
PreD1-origin length	48.7	45.5–51.5 (47.9–48.9)
PreP1 length	20.3	19.3–24.0 (20.8–23.5)
PreP2 length	36.6	35.7–40.8 (37.3–40.8)
Preanal length	51.2	47.6–53.0 (51.0–52.5)
Precaudal length	69.5	65.4–72.6 (67.8–68.9)
Pre-branchial length	17.2	15.3–20.6 (18.7–19.8)
Pre-orbital length	9.5	8.2–12.0 (9.7–12.0)
Pre-outer nostril length	4.7	3.8–6.0 (4.9–5.6)
Pre-inner nostril length	6.8	6.1–9.5 (7.1–8.8)
Pre-oral length	8.1	7.6–11.0 (8.7–10.6)
Head length	22.0	19.6–23.8 (22.6–23.8)
Mouth width	7.9	7.0–11.3 (8.0–9.0)
Internarial width	3.6	3.0–4.3 (3.4–4.0)
Upper labial furrow length	3.4	2.2–4.4 (2.8–3.5)
Lower labial furrow length	2.0	1.6–2.8 (1.9–2.1)
Orbital length	3.1	2.0–3.7 (3.1–3.5)
Nostril length	3.3	3.0–5.2 (3.2–4.0)
Interorbital width	6.2	5.1–7.6 (6.1–7.5)
1st gill height	1.6	1.0–2.7 (1.0)
3rd gill height	2.0	1.0–3.2 (1.0–2.2)
5th gill height	1.9	0.9–2.5 (0.9)
D1-D2 space	8.1	6.0–10.5 (6.9–7.8)
D1-D2 origins	13.1	10.9–14.9 (12.3)
D1-D2 insertions	14.9	12.6–16.8 (14.5)
P1-P2 space	6.8	6.9–10.2 (7.9–9.6)
P1 tip to P2 origin	2.6	1.1–4.6 (3.8–4.2)
P1-P2 origins	15.7	7.0–18.3 (14.5–17.0)
D1 base length	5.2	3.0–7.7 (3.7–4.0)
D1 height	1.5	1.1–3.9 (1.2–1.4)
D1 free lobe length	3.3	2.5–4.0 (―)
D2 base length	6.9	4.6–7.7 (6.1–6.8)
D2 height	2.3	2.1–4.3 (2.2–2.4)
D2 free lobe length	3.0	2.5–4.3 (―)
P1 anterior margin	13.3	11.0–15.3 (11.1–12.3)
P2 length	11.9	8.7–11.6 (9.9–11.5)
Anal base length (ceratotrichia)	17.1	15.9–20.6 (16.1–19.0)
Anal height (muscle)	4.9	2.7–6.2 (4.3–4.5) ...... continued on the next page