Apristurus herklotsi (Fowler, 1934)

Nakaya, Kazuhiro & Kawauchi, Junro, 2013, A review of the genus Apristurus (Chondrichthyes: Carcharhiniformes: Scyliorhinidae) from Taiwanese waters, Zootaxa 3752 (1), pp. 130-171 : 131-136

Apristurus herklotsi (Fowler, 1934)

English name: Longfin catshark Taiwanese name: Chang-wen-bi-sa Japanese name: Yari herazame

( Figures 1–6 , Table 1)

Pentanchus herklotsi Fowler, 1934: 238 , fig. 3 (original description, type locality: Philippines); Fowler, 1941: 53 (key to species and description, Philippines).

Apristurus herklotsi: Springer & Garrick, 1964: 86 (material, Philippines); Compagno, 1984: 264 (description, Philippines); Compagno, 1988: 170 (taxonomic comments, Philippines); Nakaya, 1988a: 437 (comparative materials); Nakaya, 1988b: 133, figs. 1–12 (description, Philippines and Japan); Nakaya, 1991: 999, figs. 1–8 (comparative materials, Philippines, China, and Japan); Nakaya & Shirai, 1992: 40 (fauna and zoogeography, Japan); Compagno, 1999: 478 (list); Nakaya & Sato, 1999: 315 (taxonomic comments); Nakaya & Séret, 1999: 307 (comparative materials); Yoshino & Aonuma, 2002: 130 (key to species, Japan); Compagno et al., 2005: 190 (not fig., not pl. 32, description, China, Philippines, and Japan); Ebert et al., 2013: 289 (not fig, not pl. 39, description).

Apristurus xenolepis Meng, Chu and Li, 1985: 47, fig. 4 (original description, type locality: China).

Apristurus abbreviatus Deng, Xiong & Zhan, 1985: 102 , fig. 1 (original description, type locality: China).

Apristurus brevicaudatus Chu, Meng & Li, 1986: 269, fig. 1 (original description, type locality: China).

Apristurus longianalis Chu, Meng & Li, 1986: 271, fig. 3 (original description, type locality: China).

Apristurus longicaudatus Li, Meng & Chu, 1986: 272, fig. 4 (original description, type locality: China).

Material examined. Taiwan: ASIZP 58264, 2 females, 375 mm TL and 403 mm TL, Da-xi. ASIZP 60560, 2 females, 445 mm TL and 450 mm TL, Da-xi. ASIZP 61686, female, 298 mm TL, 24–52’N, 122-01’E (East of Keelung), 423– 538 m. NMMBP 9497, 203 mm TL, female, 263 mm TL, female, 429 mm TL, male, 400 m, NMMBP 7406, 378 mm TL, female, 390 mm TL, female, 412 mm TL, female, NMMBP 14811, 295 mm TL, male, NMMBP 17510, 443 mm TL, female, Da-xi. HUMZ 170382, male, 486 mm TL, HUMZ 170415, male, 362 mm TL, HUMZ 170416, male, 336 mm TL, HUMZ 170417, female, 415 mm TL, HUMZ 170418, male, 464 mm TL, HUMZ 170419, female, 442 mm TL, HUMZ 170420, male, 430 mm TL, HUMZ 170421, female, 482 mm TL, HUMZ 170422, male, 520 mm TL, HUMZ 170448, male, 364 mm TL, HUMZ 170449, female, 450 mm TL, HUMZ 170492, female, 453 mm TL, HUMZ 170932, male, 323 mm TL, HUMZ 185159, female, 419 mm TL, HUMZ 185160, female, 402 mm TL, HUMZ 185161, female, 378 mm TL, HUMZ 185162, male, 268 mm TL, HUMZ 185169, male, 337 mm TL, all from Da-xi fishing port, near Kuei-shan Island. Other regions (type specimens): USNM 93134 (holotype of A. herklotsi ), female, 326 mm TL, Cagayan Island, Jolo Sea, Philippines (9°37′N, 121°12.5′E). ECSFI E-1547 (holotype of Apristurus abbreviates ), female, 430 mm TL, male, East China Sea, 692 m depth; ECSFI E-1000 (paratype of A. abbreviates ), female, 365 mm TL. ECSFI E-1001 (paratype of A. abbreviates ), female, 407 mm TL, East China Sea (29°28.00′N, 127°33.0′E), 655 m depth. ECSFI E-1417 (paratype of A. abbreviates ), male, 355 mm TL, East China Sea (31°24.00′N, 129°03.00′ E), 716 m depth. ECSFI E-1548 (paratype of A. abbreviatus ), male, 340 mm TL. ECSFI E-1597 (paratype of A. abbreviatus ), female, 311 mm TL, East China Sea (31°34.04′N, 129°06.00′E), 692 m depth. SCSFRI D-1125 (holotype of Apristurus brevicaudatus ), male, 397 mm TL, South China Sea, 864 m depth. SCSFRI S-6530 (holotype of Apristurus longianalis ), female, 366 mm TL, South China Sea, 533 m depth. SCSFRI D-811 (holotype of Apristurus longicaudatus ), male, 324 mm TL, South China Sea, 840 m depth. SCSFRI D-42 (holotype of Apristurus xenolepis ), female, 415 mm TL, South China Sea, 546 m depth. SFC D-32, SFC D-1126 (2 paratypes of A. brevicaudatus ), 2 males, 412–419 mm TL, South China Sea, 864 m depth. SFC D-571 (paratype of A. longianalis ), female, 359 mm TL, South China Sea, 604 m depth. SFC-564 (paratype of A. longicaudatus ), male, 330 mm TL, South China Sea, 619 m depth. Other regions (non types): BSKU 23109, female, 318 mm TL, BSKU 23110, female, 317 mm TL, 615 m depth, Kochi Prefecture, Japan. BSKU 26647, male, 320 mm TL, 900 m depth, BSKU 27598, male, 350 mm TL, 610–640 m depth, BSKU 27882, female, 437 mm TL, 520–542 m depth, Okinawa Trough, Japan. FUMT-P 10142, female, 485 mm TL, FUMT-P 10143, male, 373 mm TL, FUMT-P 10144, female, 438 mm TL, Choshi Fish Market, Chiba Prefecture, Japan.

Diagnosis. A species of Apristurus with the following characters: upper labial furrows subequal to or longer than the lowers; first dorsal fin much smaller than second dorsal fin, originating slightly posterior to pelvic fin insertion; second dorsal-fin insertion anterior to anal-fin insertion; snout narrow and long; pre-outer nostril length greater than interorbital width; abdomen short; P1–P2 space much shorter than anal-fin base length (ceratotrichia); pectoral-fin tip always extending beyond midpoint of P1–P2 space; duodenum short, less than half of valvular intestine; intestinal spiral valves 8–12; monospondylous + precaudal diplospondylous vertebrae 28-33 + 31–35; clasper hook present on edge of exorhipidion; body uniformly pale brownish to light grayish; mature size 400–450 mm TL in males and 550–600 mm TL in females.

Description. Proportional measurements and meristic counts are given in Table 1. Body cylindrical, slender and elongate ( Figure 1 ). Head dorso-ventrally flattened, posterior part of body compressed laterally. Snout very long, narrow; its tip tapering evenly. Pre-outer nostril length greater than interorbital width, 2.0–2.5 times internarial width. Pre-oral length slightly less than pre-orbital length, 3.1–4.0 times internarial width, much greater than mouth width and interorbital width. Pre-orbital length 1.9–2.1 times interorbital length, 3.4–4.9 times orbit length. Internarial width longer than orbit length and subequal to nostril width. Nostril relatively large, expanding obliquely inward from snout edge; length about half of pre-outer nostril length. Nostril-mouth space about half of internarial width. Mouth arched, with well developed labial furrows; upper labial furrow1.0–1.6 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 small placed slightly below level of horizontal axis of orbit. Five small gill slits present; fourth gill slit above pectoral-fin origin; fifth gill slit smallest above pectoral fin base. Gill septa without projection, covered with dermal denticles. Abdomen short; P1–P2 space shorter than anal-fin base length (ceratotrichia); pectoral-fin tip always reaching beyond midpoint of P1–P2 space. Pectoral fin large, broad, sub-triangular; outer margin not parallel to inner margin. Pelvic fin low and short, its length subequal to pre-inner nostril length. Dorsal fins similar in shape. First dorsal fin much smaller than second; origin slightly posterior to pelvic-fin insertion; insertion slightly posterior to anal-fin origin. Second dorsal-fin origin slightly posterior to middle of anal-fin base; insertion anterior to anal-fin insertion. Anal fin low, with a long base much greater 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 high: apex of ventral lobe rather rounded; subterminal notch distinct; length of terminal lobe twice caudal terminal lobe height. Caudal peduncle height 0.4– 0.6 times pre-outer nostril length. Duodenum short, length less than half of valvular intestine.

Intestinal spiral valves 8–12. Monospondylous vertebrae 28–33; precaudal diplospondylous vertebrae 31–35.

Teeth numerous and small, 44–60 rows on upper jaw, 44–61 rows on lower jaw; usually one (sometimes two) lateral cusp on anterior upper jaw teeth and usually two (sometimes one) on posterior upper jaw and lower jaw teeth.

Egg capsule taken from 482 mm TL specimen (HUMZ 170421) ( Figure 2 ) 47.3 mm long and 15.4 mm wide in a cylindrical shape, without coiled tendrils on both ends; anterior margin of capsule rounded without fibrous thread at each corner; lateral edges straight; posterior tip forming narrow and relatively long tapering tube. Surface of egg capsule with ridges. Color light brown.

Dermal denticles from dorso-lateral side of body ( Figure 3 ) small, 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 caudal fin. Dermal denticles densely present around the gill slits and on gill septa.

Clasper ( Figure 4 ) stout at base, tapering posteriorly. Ventral and outer sides of surface densely covered with dermal denticles. Dorsal side of clasper naked and ventral and lateral sides covered with clasper denticles; clasper hooks present on edge of exorhipidion; pseudosiphon slit-like in shape; cover rhipidion vestigial; pseudopera large and deep; exorhipidion simple in shape, lacking free posterior end.

Color. Upper and lower surfaces of body and fins uniformly pale brownish to light grayish with blackish naked areas along the fin margins. Tongue and palate blackish brown.

Size. Maximum size 520 mm TL in male ( Figure 5 ). Males less than 373 mm TL in maturity stage 1 (immature) with short claspers, less than 2.5 % TL. One male of 430 mm TL in maturity stage 2 (adolescent) with developing but soft claspers. Most males more than 397 mm TL in maturity stage 3 (adult) with long, well-developed and hardened claspers. Females less than 378 mm TL in maturity stage 1. Females in 401.5–450 mm TL in maturity stage 2. Females more in 437–482 mm TL in maturity stage 3.

Distribution. Philippines, Taiwan (Da-xi), South China Sea, East China Sea (Okinawa Trough), Mainland of Japan (Tosa Bay and northward to Choshi, Chiba Prefecture), in 533–864 m depth ( Figure 6 ).

Remarks. Apristurus herklotsi was originally described by Fowler (1934) based on an immature female collected from the Philippines. This species belongs to the ‘ longicephalus group’ (sensu Nakaya & Sato, 1999) of the genus Apristurus , typically characterized by having a very long and slender pre-outer nostril snout, which is longer than the interorbital width.

The ‘longcephalus group’ contains nine nominal species from the western Pacific and Indian oceans, but five of them are recognized as junior synonyms of Apristurus herklotsi (Nakaya, 1991) . Therefore, the ‘ longicephalus group’ contains four valid species, A. herklotsi Fowler (1934) from the Philippines, A. longicephalus Nakaya, 1975 from Japan, A. australis Sato, Nakaya & Yorozu, 2008 from Australia, and A. garricki Sato, Stewart & Nakaya, 2013 from New Zealand.

Apristurus herklotsi and A. longicephalus occurs in Taiwan, but they are clearly distinguishable by the position of first dorsal fin origin (behind pelvic insertion in A. herklotsi vs. above pelvic fin base in A. longicephalus ), the number of spiral valves (8–12 in A. herklotsi vs. 13–17 in A. longicephalus ), and the length of duodenum (less than half of valvular intestine in A. herklotsi vs. considerably long, almost equal to the valvular intestine in A. longicephalus ).

This is the first report of A. herklotsi from Taiwan.

A. herklotsi

Taiwan Holotype Other regions (other types) 10 males, 10 females female 12 males, 10 females (9 males, 5 females)

Total length (mm) 268–520 326 311–481 (311–430)

Proportion (%TL)

PreD2-origin length 55.7–60.9 57.4 54.1–59.9 (55.3–59.9)

PreD1-origin length 44.7–49.3 46.6 43.1–49.6 (43.7–49.4)

PreP1 length 21.8–25.7 24.0 22.7–25.1 (22.8–24.5)

PreP2 length 36.6–40.6 37.7 36.6–40.9 (37.2–40.1)

Preanal length 47.8–52.5 48.5 46.7–52.6 (47.7–52.6)

Precaudal length 62.9–66.9 64.7 61.9–68.3 (63.6–68.3)

Pre-branchial length 18.8–22.6 21.7 18.7–21.9 (18.7–21.6)

Pre-orbital length 11.1–13.7 13.9 11.2–14.2 (11.2–13.6)

Pre-outer nostril length 6.4–10.6 7.9 6.7–8.6 (6.7–8.1)

Pre-inner nostril length 8.5–10.6 10.3 8.6–11.0 (8.6–10.6)

Pre-oral length 10.1–12.8 11.9 10.5–14.3 (10.5–13.2)

Head length 22.7–26.9 24.9 22.6–25.8 (23.5–24.4)

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Figures

FIGURE 1. Apristurus herklotsi. A, B, C: NMMBP 17510, 443 mm TL, female, Da-xi. D: Holotype (drawing by Nakaya).

FIGURE 2. Egg capsule of Apristurus herklotsi from HUMZ 170421, female, 482 mm TL. Scale bar = 1 cm.

FIGURE 3. Dermal denticles of Apristurus herklotsi, HUMZ 185159, female, 419 mmTL. Scale bar = 0.5 mm.

FIGURE 4. Dorsal views of right clasper of Apristurus herklotsi, HUMZ 170382, male, 486 mm TL. CD, clasper denticles; CH, clasper hooks; ER, exorhipidion; PP, pseudopera; PS, pseudosiphon; PV, pelvic fin; RH, rhipidion. Scale bars = 0.25 cm.

FIGURE 5. Maturity stages of Apristurus herklotsi. Open symbols, males; solid symbols, females. Asterisks indicate holotypes.

FIGURE 6. Distribution of Apristurus herklotsi. Star, holotype; circles, non-types.