A revision of the western North Pacific swellsharks, genus Cephaloscyllium Gill 1862 (Chondrichthyes: Carcharhiniformes: Scyliorhinidae), including descriptions of two new species
Author
Schaaf-Da, Jayna A.
Author
Ebert, David A.
text
Zootaxa
2008
1872
1
28
journal article
10.5281/zenodo.183986
4ced8216-c041-4541-81aa-55e2f672a565
1175-5326
183986
Cephaloscyllium pardelotum
sp. nov.
(
Figs. 1
,
5
a, 7a;
Table 1
)
Type
Series and Locality.
Holotype
,
CAS
224876, female,
202 mm
TL, collected from Tungkang,
Taiwan
,
22°27.6'N
,
120°26.4'E
, collected by David A. Ebert on
21 April 1988
, in excellent condition.
Diagnosis.
Body comparatively slender, head short, pre-first dorsal length 48% TL. Mouth wide, its width
0.53 in
head length. Snout very short, moderately flattened, broadly rounded; anterior nasal flaps not overlapping mouth posteriorly, narrowly lobate, inner margin with a deep notch. First dorsal fin relatively small; considerably larger than second dorsal fin; originates behind half of pelvic-fin base. Pectoral fins relatively large and broad; anal fin relatively large. Color pattern elaborate; speckled dorsal saddles; three lateral clusters of spots arranged into rosettes between paired fins; dark lateral blotch between paired fins absent.
Description.
Proportional dimensions in percentage of TL are shown in
Table 1
. Head short, its length 0.27 times in precaudal length; pre-pectoral length 18.3% TL. Snout moderately flattened, broadly rounded, and short, preorbital length 0.30 times head length; 0.72 times interorbital width. Eye small, its horizontal eye length
0.19 in
head length; cat-like. Spiracle small, its diameter 0.27 times horizontal eye length. Gill openings very small, vertical length of first gill opening
0.09 in
head length. Mouth relatively small, its width 0.53 times head length; labial furrows absent. Nostrils large; internarial distance
0.24 in
mouth width; anterior nasal flaps elongate, lobed, with deep notch on inner margin, not overlapping mouth posteriorly. First dorsalfin small; first dorsal-fin height
0.40 in
length; origin about opposite or behind half of pelvic-fin base; pre-first dorsal length 48.0% TL. Second dorsal fin small, only slightly smaller than first; second dorsal-fin height
0.36 in
length; pre-second dorsal length 0.84 times precaudal length; second dorsal-fin height
0.71 in
first dorsalfin height. Pectoral fins relatively large and broad; anterior margin 0.63 times head length; base
0.72 in
anterior margin. Pelvic fin small; its length 0.14 times precaudal length; base
0.66 in
length. Anal fin relatively large; its height 0.05 times precaudal length and its length 0.14 times precaudal length; larger than either dorsal fin; second dorsal-fin height
0.71 in
anal-fin height; first dorsal-fin height about equal to anal-fin height. Caudal fin broad, asymmetrical, with subterminal notch; dorsal-lobe length 0.37 times precaudal length; ventral-lobe length
0.35 in
dorsal-lobe length.
Body firm, thick-skinned, with well calcified dermal denticles; no ridge of enlarged denticles along dorsal caudal-fin margin. Teeth very small and numerous; similar in both jaws; three cusps in females. Total vertebrae 120, monospondylous 44, precaudal 74, and pre-caudal diplospondylous 30.
Size and sexual maturity.
Unknown at present.
FIGURE 1.
Cephaloscyllium pardelotum
sp. nov.
holotype (CAS 224876); a. lateral view; b. dorsal view. Photos by D.A. Ebert
FIGURE 2.
Scatter diagram of proportional dimensions of anal-fin posterior margin length for select
Cephaloscyllium
species.
Coloration.
Background color golden to light brown dorsally; pale ventrally; small brown specks cover dorsal and lateral surfaces; dark lateral blotch between paired fins absent. Seven dorsal H-shaped saddles clearly defined; first in line with the gills, second above pectoral-fin insertion, third just before pelvic-fin origin, then one at each dorsal-fin base, one at caudal-fin origin, and dorsal-caudal lobe; saddles open, outline brown and variegated, not dark and solid. Rosette pattern present, consisting of a circle of 5–6 small brown speckles; three rosettes present laterally between the pectoral and pelvic fins; rosettes on head include one behind each orbit, one between orbits, one over each gill series, and a few on snout; each paired fin has one rosette placed dorsally, larger rosettes on larger fins; paired rosettes are present laterally above pelvic-fin origin, between dorsal fins, caudal peduncle, and lower caudal lobe.
Comparison with other species.
Morphometric data are presented in
Table 1
.
Cephaloscyllium pardelotum
sp. nov.
differs from
C
.
circulopullum
in lacking a dark lateral blotch between the pectoral and pelvic fins, and possessing a lobed anterior nasal flap.
Cephaloscyllium pardelotum
sp. nov.
has a remarkably distinct color pattern from
C
.
fasciatum
. Although the two species have open dorsal saddles,
C
.
pardelotum
sp. nov.
possesses saddle borders that are not dark and solid as in
C
.
fasciatum
. In contrast, the saddle borders of
C
.
pardelotum
sp. nov.
are variegated and patchy and form an H-shape. Also, this new species has distinctive rosettes and no reticulated lines. The anal fin is slightly larger in the new species. Anal-fin posterior margin is 0.07 times in precaudal length for
C
.
pardelotum
sp. nov.
, but 0.03–0.04 times in precaudal length for
C
.
fasciatum
(
Fig. 2
).
Cephaloscyllium pardelotum
sp. nov.
differs from
C
.
sarawakensis
in color pattern, and size and position of the dorsal fins. The new species does not display the distinctive polka-dots of juvenile
C
.
sarawakensis
, nor the dark lateral blotch of
C
.
sarawakensis
. Overall, both dorsal fins of
C
.
pardelotum
sp. nov.
are smaller than in other WNP species of swellshark. The first dorsal-fin base is relatively short in
C
.
pardelotum
sp. nov.
(
Fig. 3
). This length is 0.08 times in precaudal length in
C
.
pardelotum
sp. nov.
, whereas
C
.
sarawakensis
has a dorsal-fin base between
0.09–0.12 in
precaudal length. The first dorsal-fin height is relatively short (
Fig. 4
) in
C
.
pardelotum
sp. nov.
, at
0.05 in
precaudal length. This measurement is 0.06–0.07 times in precaudal length in
C
.
sarawakensis
. In
C
.
pardelotum
sp. nov.
,
the first dorsal fin originates behind the anterior half of the pelvic-fin base. In
C
.
sarawakensis
, however, the first dorsal fin originates closer to the pelvic-fin origin.
Cephaloscyllium pardelotum
sp. nov.
can be separated from adult
C
.
umbratile
by overall color pattern, and morphology of the anterior nasal flap.
Cephaloscyllium umbratile
does not have open saddles, nor are they H-shaped.
FIGURE 3.
Scatter diagram of proportional dimensions of first dorsal-fin height for select
Cephaloscyllium
species.
FIGURE 4.
Scatter diagram of proportional dimensions of first dorsal-fin base length for select
Cephaloscyllium
species.
Remarks.
If young similar-sized specimens of
C
.
pardelotum
sp. nov.
,
C
.
circulopullum
,
C
.
fasciatum
,
C
.
sarawakensis
, and
C
.
umbratile
are examined side-by-side, it is fairly easy to tell that they are all separate species (
Fig. 5
). Although the color pattern of adult
C
.
pardelotum
sp. nov.
is presently unknown, its juvenile markings are quite distinct from any other
Cephaloscyllium
within this region.
Distribution.
Cephaloscyllium pardelotum
sp. nov.
is known only from off the coast of southern
Taiwan
.
Etymology.
The species is named after the Latin
pardus
for leopard, referring to the rosette-type spots along the dorsal and lateral surfaces.
Common name.
Leopard-spotted swellshark.