Cephaloscyllium fasciatum Chan, 1966

Cephaloscyllium fasciatum Chan, 1966 View in CoL

English name: Reticulate swellshark Taiwanese name: Tiao-wen-tou-sa ( Figures 1–3 View FIGURE 1 View FIGURE 2 View FIGURE 3 , Table 1 View TABLE 1 )

Cephaloscyllium fasciatum Chan, 1966 , pp. 232–236, fig. 6, 7 (a, c), 8, plate (original description); Springer, 1979, pp. 38–39, figs. 20–21; Compagno, 1984, pp. 297–298; Compagno, 1988, p. 113; Compagno et al., 2005, p. 216, pl. 36; Ebert et al., 2013, p. 325, pl. 43.

Cephaloscyllium pardelotum Schaaf-da Silva & Ebert, 2008, p. 3, fig. 1; Ebert et al., 2013, p. 327, pl. 44. Cephaloscyllium maculatum Schaaf-da Silva & Ebert, 2008, p. 7, fig. 6; Ebert et al., 2013, p. 327, pl. 44. [non] C. fasciatum: Last & Stevens, 1994 , p. 197, pl. 23.

Material examined. Taiwan: ASIZP 57906, female, 155 mm TL (Dong-gang, Pingtung, 22º47’N, 120º43’E). ASIZP 57928, 1 male, 229 mm TL, 3 females, 206-232 mm TL (Dong-sha Island, South China Sea, 19º85’N, 114º03’E). ASIZP 62203, female, 198 mm TL (Fong-gang, Pingtung, 100 m). ASIZP 62205, male, 189 mm TL (Fong-gang, Pingtung, 300 m). NMMB-P 0 434, male, 216 mm TL (Dong-gang, Pingtung). NMMB-P 6105, male, 164 mm TL (Dong-gang, Pingtung). NMMB-P 11091, female, 211 mm TL (Dong-gang, Pingtung). NMMB-P 11092, male, 215 mm TL (Dong-gang, Pingtung). NMMB-P 12652, female, 160 mm TL (no data). NMMB-P 14043, male, 178 mm TL (Dong-gang, Pingtung). NMMB-P 14526, male, 180 mm TL (Dong-gang, 300m). NMMB-P 14561, male, 217 mm TL (Fong-gang, Pingtung, 300 m). NMMB-P 16158, female, 212 mm TL (Donggang, Pingtung). NMMB-P 16170, male, 198 mm TL (Dong-gang, Pingtung). NMMB-P 16171, male, 206 mm TL (Dong-gang, Pingtung). NMMB-P 16506, male, 192 mm TL (Dong-gang, Pingtung). NMMB-P 17123, female, 224 mm TL (Dong-gang, Pingtugng). NMMB-P 17176, male, 161 mm TL (Dong-gang, Pingtugng). NMMB-P 17177, male, 144 mm TL (Dong-gang, Pingtugng). NMMB-P 17123, female, 224 mm TL (Dong-gang, Pingtugng). HUMZ-P 213792, male, 175 mm TL (Dong-gang, Pingtung). Other regions: BMNH 1965.8.11.1 (holotype), female, 422 mm TL (417.5 mm TL when examined by Inoue) (off east-southeast of Cape Bantangan, Vietnam, 15º55.7’N, 109º28.5’E).

Diagnosis. Dorsal sides of body and fins with complex reticulations. Eight open-centered dark brown saddles on body; first saddle immediately behind eye, second saddle above gill openings, third saddle above inner margin of pectoral fin, fourth saddle above middle between pectoral and pelvic fins. Dorsal sides of pectoral and pelvic fins with a loop pattern. Small species maturing at a size less than 422 mm TL (female) and attaining at least 422 mm TL (holotype).

Description. Proportional measurements and meristic counts are in Table 1 View TABLE 1 .

Body slender ( Figure 1 View FIGURE 1 ). Head large and well depressed. Trunk thick, tail slender. Caudal peduncle slender and long; length about two times its height. Caudal fin axis a little elevated.

Snout short, its tip rather pointed, dorsal side flat. Interorbital area flat. Nostrils closer to mouth than to snout tip. Anterior nasal flap well developed, extending as a lobe, without or with shallow notch on its posterior margin; flap not reaching mouth. Posterior nasal flap well developed. Internarial space almost equal to nostril width. Mouth wide and high; width more than two times preoral length (without teeth); lower jaw almost straight along the side with a flat symphysis. Labial furrows mostly absent from both jaws, rarely with a small one on lower jaw. Eye small, slender. Spiracle small, behind and slightly below eye. Gill openings short; fourth and fifth openings on base of pectoral fin.

Pectoral fin moderate in size; its apex and free rear tip moderately rounded; posterior margin slightly concave in adult and linear or slightly convex in young. First dorsal fin origin about center of body; origin above anterior 1/ 3 to middle of pelvic base; base length shorter than pelvic-anal fin space; apex well rounded and its free rear tip slightly rounded; posterior margin linear in adult and well convex in young. Second dorsal fin considerably smaller than first dorsal fin; origin above anterior 1/3 of anal base; base much shorter than anal fin base; apex well rounded; free rear tip bluntly pointed. Pelvic fin insertion below middle of first dorsal fin base; apex broadly rounded. Anal fin larger than second dorsal fin; origin below posterior 1/3 of interdorsal space; insertion opposite to second dorsal fin insertion; base length longer than anal-lower caudal space; apex well rounded; free rear tip pointed; anterior margin long and convex; posterior margin rounded. Caudal fin slender and small, with a moderately developed lower lobe and a distinct subterminal notch; no enlarged dermal denticles on its dorsal and preventral margin; terminal and subterminal margin linear in adult and well rounded in young.

Teeth: number of teeth on both jaws relatively fewer: upper jaw 58 (holotype), lower jaw 56 (holotype) (Chan, 1966); all teeth with 3 or 5 cusps, principal cusp longest with a few smaller cusps on both sides; teeth near symphysis on both jaws symmetrical; lateral teeth more asymmetrical toward side of jaws.

Dermal denticles: dermal denticles on lateral side of body above pectoral fin thick with 3 cusps; lateral cusps indistinct; a strong medial ridge and numerous weak ridges running from base toward each cusp.

Vertebrae: monospondylous vertebrae 42–47 (holotype 45), precaudal diplospondylous vertebrae 30–35 (holotype 33), precaudal vertebrae 72–81 (holotype 78).

Spiral valves: 9 (holotype).

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1 taken by Inoue

2 from Shaarf-da Silva & Ebert (2008),

3 back-calculated from Fig. 7 View FIGURE 7 b in Shaarf-da Silva & Ebert (2008).

Color. Holotype (adult, Figure 1 View FIGURE 1 ): Dorsal and lateral side of body reticulated; dark brown lines forming opencentered dorsal saddle blotches present on light brown ground color; ground color on underside of body, paired fins and anal fin light brownish; numerous small dark brown spots present on dorsal side of body. Eight dorsal saddle blotches on body: first saddle immediately behind eye, second saddle above gill openings, third saddle above inner margin of pectoral fin, fourth saddle above middle between pectoral and pelvic fins, fifth saddle on first dorsal fin, sixth saddle on second dorsal fin, seventh saddle on caudal fin just behind caudal peduncle, and eighth saddle on posterior half of caudal fin.

Additional specimens: Ground body color brownish or light brownish dorsally, whitish ventrally. Ventral side of head slightly dark marginally. Many complex and variable reticulation on body and fins. Eight open-centered dark brown saddle blotches on body, each one greatly variable in shape (below). Position of the saddle blotches are: first saddle blotch immediately behind eye, second one above gill openings, third one above inner margin of pectoral fin, fourth one above middle between pectoral and pelvic fins, fifth one on first dorsal fin, sixth one on second dorsal fin, seventh one on caudal fin just behind caudal peduncle, and eighth saddle blotch on posterior half of caudal fin. One loop each on dorsal sides of pectoral and pelvic fins. Lateral loops present on snout, below eye, around first and second gill openings, above pectoral fin base, between third and fourth saddles. Many dark brown dots, sometimes white dots, on lateral side of body between saddles and loops. Dorsal side of pectoral fin dotted. Anal fin and lower lobe of caudal fin with lines.

Variation ( Figure 2 View FIGURE 2 ): Reticulation on body and fins greatly variable, as shown below. Reticulation patterns on right and left sides sometimes different in a same specimen (NMMB-P 17177). Reticulation patterns mostly clear, sometimes obscure and broken into thin or thick lines (NMMB-P 11019). Saddle lines variable in shape, sometimes forming small loops along mid-dorsal line (NMMB-P 6105), elongate to form triangular or elliptic circles on lateral side of body (NMMB-P 16506). Saddles sometimes darker inside (NMMB-P 14043). First saddle completely separate into right and left portions (NMMB-P 14013), or partly separate (NMMB-P 16506). Second saddle sometimes continuous with lateral loops above pectoral base and gill openings (NMBB-P 17177), or with a loop around gill openings (NMMB-P 12652). Third saddle continuous with a lateral loop above pectoral base (NMMB- P 17123). Fourth saddle often continuous with lateral loops between pectoral and pelvic fins (NMMB-P 17176). Lateral loops greatly variable, triangular, quadrangular (NMMB-P 6105), polyangular, circular (NMMB-P 12652), elliptical (NMMB-P 14526) and combination of these in shape. Dark dots absent (NMMB-P 17123) or present (NMMB-P 16506). White spots mostly absent, rarely faintly present (NMMB-P A434).

Size. Largest specimen 422 mm TL (holotype). Size at maturation less than 422 mm TL (female).

Distribution. Western North Pacific Ocean and South China Sea (off South Taiwan, China, Philippines and Vietnam); 112–172 fathoms (Chan, 1966), 200–400 m (Ho, pers. obs.).

Remarks. This species was described based on a maturing holotype and four juvenile paratypes collected from Vietnam, and is strongly characterized by its reticulated color patterns on body and fins. Recently, Schaaf-da Silva & Ebert (2008) reviewed the western North Pacific swellsharks, and described two new species, Cephaloscyllium pardelotum and C. maculatum , both similar to C. fasciatum in possession of reticulated color patterns on body and fins.

Schaaf-da Silva & Ebert (2008) differentiated Cephaloscyllium pardelotum from C. fasciatum by the condition of saddle borders (variegated, patchy and forming an H-shape in C. pardelotum ), rosettes (distinctive in C.

pardelotum ), relative length of anal fin posterior margin (0.07 times in PCL in C. pardelotum , vs. 0.03–0.04 in C. fasciatum ).

They also distinguished Cephaloscyllium maculatum from C. fasciatum by the color patterns (less variegated in C. maculatum ), condition of anterior nasal flap (short and triangular in C. maculatum ), internarial space (4.0% TL in C. maculatum vs. 2.7–3.2% TL in the type specimens [4.5% TL in their non-type material] of C. fasciatum ), mouth width (7.4% TL vs. 10.5–11.8% [10.5%]), and mouth length (3.7% TL vs. 5.5–6.2% [7.0%]).

As mentioned in the above description, Cephaloscyllium fasciatum has a highly variable color patterns. The reticulation and lines are very clear in some specimens, but thick, thin, obscure, variegated or broken in other specimens. Saddle blotches are also quite variable, i.e. narrow, wide, subdivided into some smaller parts, connected with other saddles, and/or looped. The lateral blotches (loops) vary between angular, rectangular, round or elliptical in form, and are broken into some loops, separate or connected each other, or continuous with the saddle blotches. The saddle and lateral blotches (loops) are clear inside in many of the specimens, but dark in the others. The color patterns were often different between right and left sides even in a same individual ( Figure 3 View FIGURE 3 ). Schaaf-da Silva & Ebert (2008) used the color patterns to distinguish their two new species from C. fasciatum , but the colorations of C. pardelotum and C. maculatum are within the variations present in C. fasciatum .

Schaaf-da Silva & Ebert (2008) used relative length of anal fin posterior margin (0.07 vs. 0.03–0.04 times in PCL in Cephaloscyllium pardelotum and C. fasciatum , respectively) to distinguish them. However, the relative length of anal fin posterior margin is 0.075 in PCL in their comparative material of C. fasciatum (SU 34041), widening the range to 0.03–0.075 for C. fasciatum . Therefore, C. pardelotum is included within this range and is indistinguishable from C. fasciatum .

Schaaf-da Silva & Ebert (2008) gave a graph of internarial space (their fig. 8, p. 12), suggesting a specificlevel difference of Cephaloscyllium maculatum from C. pardelotum and C. fasciatum . They also gave figures of ventral side of head of these species (their figs. 7a–c, p. 11). Their figure 7b ( C. maculatum ) indicates that the internarial space and nostril width are almost same in this species, but the propotional measurements given in Table 1 View TABLE 1 are much different, or 4.0% TL for internarial space and 2.7% TL for nostril width. Their figure 7a shows C. pardelotum , and the measurements and figure of this species correspond well. So the three discriminating characters given in the original description were back-calculated from their figure 7b, based on preoral length and nostril width (See Table 1 View TABLE 1 , column C. maculatum ). Results of back-calculation are that the internarial space is 2.5– 3.2% TL (instead of 4.0% TL in the original description), mouth width 8.1–10.2% (7.4%), and mouth length 3.1– 4.0% (3.7%), and indicate these measurements are within or almost within the ranges of C. fasciatum .

Short and triangular (not lobate) anterior nasal flap is another diagnostic character of Cephaloscyllium maculatum . The type specimen (417.5 mm TL) of C. fasciatum has a distinct lobate anterior nasal flap. Although the anterior nasal flaps are weakly lobate in most of the specimens, its shape is easily changeable, because the anterior nasal flap is very small and soft especially in smaller specimens. The right and left nasal flaps are different in shape in some specimens. For these reasons, it was often difficult to judge whether the anterior nasal flap of the specimens is short triangular or lobate, especially in smaller specimens.

Conclusively, Cephaloscyllium pardelotum and C. maculatum are considered junior synonyms of C. fasciatum .