Cephaloscyllium umbratile

Schaaf-Da, Jayna A. & Ebert, David A., 2008, A revision of the western North Pacific swellsharks, genus Cephaloscyllium Gill 1862 (Chondrichthyes: Carcharhiniformes: Scyliorhinidae), including descriptions of two new species, Zootaxa 1872, pp. 1-28 : 15-21

Cephaloscyllium umbratile ( Jordan & Fowler 1903)

( Fig. 12 , 5 d, 7d, 10c; Table 2 )

Scyllium laticeps Nystrom 1887: 49 ; Ishikawa & Matsuura 1897: 62.

Cephaloscyllium umbratile ( Jordan & Fowler 1903): 602, Fig. 1 ; Garman 1913: 80; Fowler 1914: 32; Chen 1963: 29, Fig. 9 ; Lindberg & Legeza 1959: 44, Fig. 24; Chan 1966: 229, Figs. 4 , 5 , 7 b, 7d, pl. II; Bessednov 1969: 27, Figs. 9 , 10 ; Compagno et al. 2005a: 218, pl. 36.

Scyliorhinus umbratilis Regan 1908: 459 .

Cephaloscyllium formosanum Teng 1962: 48 , Fig. 11 .

Cephaloscyllium isabellum (in part as western North Pacific “ umbratile ”) Compagno 1984: 298.

Type Series and Locality. Holotype, SU 12693, mature male, 975 mm TL, collected from Nagasaki, Japan, 32°43'N, 129°50'E, collected by M. Yahiro, stuffed skin.

Diagnosis. Body comparatively stocky, head short, a large species of Cephaloscyllium . Snout broad and relatively long; anterior nasal flaps not overlapping mouth posteriorly. Mouth broad and strongly arched. First dorsal-fin origin behind half of pelvic-fin base; first dorsal-fin base usually less than interdorsal space, especially in larger specimens; anal–caudal space and dorsal–caudal space relatively long. Light crème to beige background with brown, dark grey, and/or tan spots ventrally, laterally, and on fins; seven broad tan dorsal saddles, three of which are on the head; saddles apparent in juveniles but mottled to the point of obscurity in adults.

Description. Body fusiform, relatively stout; head long 21.3% TL, depressed, height 0.89 times width. Snout relatively long, flattened; preorbital length 0.29 times in head length and 0.70 times interorbital width; narrowly rounded in lateral view; width broad, 0.43 times head length; horizontal length 1.46 in eye length. Eye small, its horizontal length 7.61 in head; 2.0 times height; cat-like; nearer tip of snout than first gill opening. Spiracle very small and circular, its maximum diameter 7.0 in eye length; close behind eye. Gill openings large, subequal in size; becoming progressively smaller posteriorly; height of first gill slit 0.10 in head length. Mouth broad, strongly arched; half as long as wide, width 1.18 in preoral length; labial furrows absent. Nasals very large, nearer tip of snout than eye, not confluent with mouth; anterior nasal flaps not extending to the mouth; not elongate nor not bell-shaped; only slightly oblique; nostril width about equal to internarial distance. First dorsal fin large, much larger than second dorsal fin; placed far back on the body; slightly rounded; posterior margin slightly convex, length 8.9% TL; first dorsal-fin origin just posterior to pelvic-fin insertion; first dorsal-fin insertion well forward of anal-fin origin; first dorsal-fin length 0.75 in second dorsal fin; first dorsal-fin height 0.38 in second dorsal fin. Second dorsal fin relatively small; nearer first dorsal than base of caudal lobe; upright, lobate, or convex posterior margin; short free rear tip; fin origin just behind anal-fin origin; interdorsal space 0.96 in length from snout tip to pectoral-fin origin. Pectorals large; as broad as long; angles rounded; anterior-margin length 0.58 times head length; pectoral-fin base 0.64 in anterior-margin length. Pelvic fin small, length 0.11 times precaudal length; base 0.69 in length. Anal fin nearly as large as first dorsal; much larger than second dorsal; length 0.10 times precaudal length; second dorsal-fin height 0.44 in anal-fin height. Caudal fin large, asymmetrical, broad, longer than head; subterminal notch present; ventral lobe much larger in area than dorsal lobe; ventral-lobe length 0.39 in dorsal-lobe length; caudal peduncle relatively long, its length 6.8% TL.

Body firm, thick-skinned, with well-calcified dermal denticles; surpaorbital crest of the chondrocranium present. Teeth similar in upper and lower jaws; small and numerous; multicuspid in 2–3 series, each with a long median cusp flanked by one lateral cusplet, less than one half the length of median cusp, cusps conical at the apex, striate near the bases. Upper jaw tooth count, 59; lower jaw tooth count, 62. Vertebral counts based on a 193 mm specimen (CAS 224880) are: total vertebral number 129, monospondylous 47, precaudal 81, and pre-caudal diplospondylous 34.

Size and sexual maturity. According to the literature and specimens studied, males mature at about 947– 948 mm TL and females 948–1011 mm TL; maximum length at least 1200 mm for males and 1100 mm for females ( Compagno et al. 2005a).

Coloration. In life lightly pigmented background color, from crème to light-beige; pale below; dark-grey, tan, and deep brown mottling dorsally and laterally, and on fins; spotting and mottling simple in juveniles and intense in adults, possibly obscuring the dorsal saddles; the dorsum, lateral surfaces, and ventrum have no obvious boundaries; the ventral surface has much fewer markings. Seven dorsal bands in younger specimens which seem to fade in adulthood; the first behind eye, second over base of pectoral, next between it and first dorsal where another is, and finally last at second dorsal; two broad cross bars on caudal, one at base of caudal, the other near its tip.

Comparison with other species. Cephaloscyllium umbratile , formerly synonymized with C. isabellum , is upheld as a valid species based on the combination of a few key characters. Cephaloscyllium umbratile is not a dwarf species of swellshark. Hence, maximum size differences allow it to be distinguished from C. circulopullum , C. fasciatum , and C. sarawakensis .

The color pattern of C. umbratile can be used to for field identification; it has seven distinct dorsal bands that are usually deep-brown in life, three of which are pre-first dorsal fin. However, taxonomy should not be based on these bands alone, as they become obscure in adulthood. We disagree with Yano et al. (2005) concerning the dark lateral blotch in this species. Although adult C. umbratile may appear to have a dark lateral blotch between the paired fins due to intense mottling, there is no such blotch in younger, smaller specimens. Since young C. umbratile lack a dark lateral blotch, it can be easily distinguished from C. circulopullum and C. sarawakensis .

Additionally, a few characters can be used to separate this swellshark from other large-sized species, specifically C. isabellum . The first dorsal-fin base of C. umbratile is relatively short ( Fig. 13 ) in proportion to TL. The length of the first dorsal base of C. umbratile remains at a constant proportion to TL compared to C. isabellum . Cephaloscyllium isabellum has a dorsal-fin base that increase slightly with increased TL.

The anal–caudal space tends to be greater in C. umbratile than in C. isabellum ( Fig. 14 ). In these two specimens, the anal–caudal space is 5.5–7.0% TL, and 4.3–5.4% TL respectively. The caudal peduncle length increases with TL in C. umbratile , whereas in C. isabellum , it stays proportional to TL. The dorsal–caudal space is generally greater in C. umbratile than in C. isabellum ; this measurement ranges from 6.2–8.5% TL ( Fig. 15 ). By comparison, this measurement of C. isabellum ranges from 4.3–5.8%.

Remarks. The Japanese swellshark was originally described from a 975 mm specimen; a stuffed skin that apparently went missing. Springer (1979) synonymized C. umbratile with C. isabellum , based on the lack of strong morphometric differences. However, in his report he measured only 12 specimens and it is unclear how many were C. umbratile , and how many were C. isabellum . Because it was lost Springer did not view the C. umbratile holotype specimen, which is the only type material catalogued for this species. Springer published morphometric values for three C. isabellum specimens that are included in this report; but no data on the C. umbratile specimens. Consequently, it is unknown what he meant by “inconclusive morphometric differences” ( Springer 1979). The redescription of C. umbratile is based on the holotype specimen, that was subsequently found, and morphometric data are presented in Table 2 .

Compagno (1984) reported that C. umbratile is a synonym of C. isabellum , but he suggested three types of this species: a true C. isabellum type, a true C. umbratile type, and a pseudo- umbratile type. Currently, it is understood that the true C. isabellum type refers to the Australian species, and the true C. umbratile type refers to the Japanese species. It has been established that the specimens Compagno refers to as pseudoumbratile from Hong Kong are actually C. sarawakensis (L.J.V. Compagno, pers. comm.).

Distribution. Cephaloscyllium umbratile occurs in the western North Pacific, including Taiwan, Japan, and the China Sea ( Compagno et al. 2005a).

Etymology. The species was named after the Latin umbra for shaded.

Common name. Japanese swellshark.

Figures

FIGURE 1. Cephaloscyllium pardelotum sp. nov. holotype (CAS 224876); a. lateral view; b. dorsal view. Photos by D. A. Ebert

FIGURE 4. Scatter diagram of proportional dimensions of first dorsal-fin base length for select Cephaloscyllium species.

FIGURE 5. Lateral views of the WNP Cephaloscyllium, all about 220 mm TL; a. Cephaloscyllium pardelotum sp. nov.; b. Cephaloscyllium maculatum sp. nov.; c. Cephaloscyllium fasciatum; d. Cephaloscyllium umbratile; e. Cephaloscyllium sarawakensis; f. Cephaloscyllium circulopullum. Illustration by J. A. S. - Da Silva.

FIGURE 7. Anterior nasal flaps of the WNP Cephaloscyllium, all about 220 mm TL; a. Cephaloscyllium pardelotum sp. nov.; b. Cephaloscyllium maculatum sp. nov.; c. Cephaloscyllium fasciatum; d. Cephaloscyllium umbratile; e. Cephaloscyllium sarawakensis; f. Cephaloscyllium circulopullum. Illustration by J. A. S. - Da Silva.

FIGURE 9. Scatter diagram of proportional dimensions of mouth width for select Cephaloscyllium species.

FIGURE 10. Dorsal view of select juvenile Cephaloscyllium; all about 200 mm TL; a. Cephaloscyllium sarawakensis (CAS 224882); b. Cephaloscyllium maculatum sp. nov. (CAS 224877); c. Cephaloscyllium umbratile (CAS 224880). Photo by D. A. Ebert.

FIGURE 11. Cephaloscyllium fasciatum holotype (BMNH 1965.8.11.1); a. lateral view; b. dorsal view. Photos by D. A. Ebert and J. A. S. - Da Silva.

FIGURE 12. Cephaloscyllium umbratile holotype (SU 12693); a. lateral view; b. dorsal view; c. ventral view. Photo courtesy of the California Academy of Sciences.

FIGURE 13. Scatter diagram of proportional dimensions of first dorsal-fin base length for selected Cephaloscyllium species.

FIGURE 14. Scatter diagram of proportional dimensions of anal – caudal space for selected Cephaloscyllium species.

FIGURE 15. Scatter diagram of proportional dimensions of dorsal – caudal space for select Cephaloscyllium species.

Tables

TABLE 2. Morphometric and meristic data for the holotype (HT) specimen for Cephaloscyllium umbratile (SU 12693), including mean and range for the C. umbratile specimens available, and Cephaloscyllium fasciatum (BMNH 1965.8.11.1), plus the paratype (PT) specimen for C. fasciatum (BMNH 1965.8.11.5), and one available specimen (SU 34041). TL is the actual measurement in millimeters; all other measurements are expressed as percentage of TL. Abbreviations as in Table 1.

C. umbratile C. umbratile	C. fasciatum	C. fasciatum	C. fasciatum
HT Comparative Material	HT	PT	Comparative Material
SU 12693 (n=18)	BMNH	BMNH	SU 34041
Measurement Mean Min Max	1965.8.11.1	1965.8.11.5
TL 975 360 178 1015	421	224	111
PCL 81.6 76.3 72.0 80.8	78.4	74.1	73.9
PD2 69.9 63.1 59.3 70.0	67.6	60.1	61.8
PD1 56.4 49.0 45.3 56.1	53.2	45.8	49.2