Squalus rancureli Fourmanoir, 1979, a new junior synonym of the blacktailed spurdog S. melanurus Fourmanoir, 1979, and updated diagnosis of S. bucephalus Last, Séret & Pogonoski, 2007 from New Caledonia (Squaliformes, Squalidae)
Author
Viana, Sarah T. F. L.
Author
De Carvalho, Marcelo R.
text
Zoosystema
2018
2018-05-09
40
9
159
177
journal article
10.5252/zoosystema2018v40a9
ea9316c2-9a82-40ef-9a38-378b376126be
1638-9387
3738290
urn:lsid:zoobank.org:pub:9D8598BA-0709-4C94-A156-D5BC6D8DA523
Squalus bucephalus
Last, Séret & Pogonoski, 2007
Bighead spurdog; Aiguillat à grosse tête
(
Figs 9-15
;
Tables 2-3
)
Squalus bucephalus
Last, Séret & Pogonoski, 2007: 23-29
(original description; illustrated.
Type
by original designation.
Type
locality Norfolk Ridge, south of
New Caledonia
,
405-411 m
depth). —
Ebert
et al.
2013: 78
, 86 (cited, description; Southwest Pacific Ocean). —
Weigmann 2016: 903
(listed; Southwestern Pacific Ocean). —
Bernot & Boxshall 2017: 275-276
, 288 (cited, listed;
New Caledonia
).
Squalus
sp. –
Séret 1994: 7
(listed;
New Caledonia
).
MATERIAL EXAMINED
. —
MNHN-IC-1997-3634,
juvenile
♂
,
520 mm
TL,
Norfolk
Ridge
,
New Caledonia
,
24°43’1”S
,
168°6’0”E
,
500-600 m
depth
;
MNHN-IC-1997-3635,
juvenile
♀
,
476 mm
TL,
Norfolk
Ridge
,
New Caledonia
,
24°43’1”S
,
168°6’0”E
,
500- 600 m
depth
;
MNHN-IC-1997-3636,
juvenile
♀
,
495 mm
TL,
Norfolk
Ridge
,
New Caledonia
,
24°43’1”S
,
168°6’0”E
,
500-600 m
depth
;
MNHN-IC-1997-3641 (
paratype
of
S. bucephalus
),
juvenile
♀
,
430 mm
TL,
Norfolk
Ridge
,
New Caledonia
,
23°39’0”S
,
167°43’59”E
,
420-470 m
depth
;
MNHN-IC-1997-3657,
adult
♂
,
705 mm
TL,
New Caledonia
,
23°43’1”S
,
168°15’0”E
,
405-411 m
depth
;
MNHN-IC-1997-3659,
adult
♂
,
805 mm
TL,
Stylaster Seamount
,
Norfolk
Ridge
,
New Caledonia
,
23°37’1”S
,
167°39’0”E
,
486-962 m
depth
;
MNHN-IC-1997-3662,
adult
♂
,
795 mm
TL,
Stylaster Seamount
,
Norfolk
Ridge
,
New Caledonia
,
23°36’0”S
,
167°40’59”E
,
448-880 m
depth
;
MNHN-IC-1998-1017,
adult
♂
,
810 mm
TL,
New Caledonia
,
23°43’1”S
,
168°15’0”E
,
405-411 m
depth
;
MNHN-IC-2006-1754 (
holotype
of
S. bucephalus
),
juvenile
♂
,
550 mm
TL,
Norfolk
Ridge
, south of
New Caledonia
,
23°43’S
,
168°16’E
,
405-411 m
depth, collected on
28.XI.1993
;
NMNZ
P 34030 (
paratypes
of
S. bucephalus
), two
adult
♂
,
787-802 mm
TL,
Stylaster Seamount
,
Norfolk
Ridge
,
New Caledonia
,
23°35’S
,
167°42’E
,
448-880 m
depth
.
GEOGRAPHICAL DISTRIBUTION. —
Squalus bucephalus
is endemic to
New Caledonia
in the Southwestern Pacific Ocean (
Fig. 15
).
DIAGNOSIS. — Short-snouted dogfish shark from
New Caledonia
that it is distinguished from its congeners by: head conspicuously humped dorsal-posteriorly and wide, its width at mouth 13.5% (12.1-13.9%) TL; anterior margin of nostrils conspicuously bilobate and broad; mouth straight and wide, its width 8.7% (7.6-8.8%) TL; caudal fin very slender on upper and lower lobes; caudal fin elongate, its dorsal caudal margin length 24.2% (21.7-23.9%); smaller pelvic-caudal space 24.9% (23.1-
FIG. 9. —
Squalus bucephalus
Last, Séret & Pogonoski, 2007
in lateral view:
A
, MNHN-IC-1998-1017, adult male, 810 mm TL;
B
, MNHN-IC-1997-3636, juvenile female, 495 mm TL. Scale bars: 50 mm.
FIG. 10. — Detail of head in anterior dorsal view (
A
) and right nostrils (
B
) of holotype of
Squalus bucephalus
Last, Séret & Pogonoski,2007
(MNHN-IC-2006-1754, juvenile male, 550 mm TL). Scale bar: A, 20 mm; B, not to scale.
26.3%) TL. It is clearly separated from
S. melanurus
by snout conspicuously short, its prenarial length 1.0-1.1 times distance nostril-upper labial furrow (vs snout conspicuously elongate, its prenarial length 1.4-1.7 times distance nostril-upper labial furrow in
S. melanurus
), prespiracular length (12.2-14.0% TL for
S. bucephalus
vs 14.7-16.8% TL for
S. melanurus
), and preoral length (9.2-10.9% TL for
S. bucephalus
vs 12.6-14.3% TL for
S. melanurus
). It is further distinct from this species by having lower caudal lobe conspicuously white (vs conspicuously black), and dermal denticles unicuspidate and lanceolate (vs tricuspidate and rhomboid).
Squalus bucephalus
is also separated from
S. melanurus
by number of monospondylous (49 vs 41 for
S. melanurus
), caudal (31 vs 26-29 for
S. melanurus
), and total vertebrae (124 vs 114-120 for
S. melanurus
).
FIG. 11. — First (
A
,
C
) and second (
B
,
D
) dorsal fins of
Squalus bucephalus
Last, Séret & Pogonoski, 2007
:
A
,
B
, MNHN-IC-1998-1017, adult male, 810 mm TL;
C
,
D
, MNHN-IC-1997-3636, juvenile female, 495 mm TL. Scale bars: 20 mm.
FIG. 12. — Pectoral fin in ventral view (
A
) and right clasper in dorsal view (
B
) of
Squalus bucephalus
Last, Séret & Pogonoski, 2007
:
A
, MNHN-IC-1998-1017, adult male, 810 mm TL;
B
, NMNZ P 34030 (paratype), adult male, 787 mm TL. Abbreviations:
ap
, apopyle;
cg
, clasper groove;
hp
, hypopyle;
P2
, pelvic fin;
rh
, rhipidion. Scale bar: 20 mm.
TABLE 3. — External measurements for
Squalus bucephalus
Last, Séret & Pogonoski, 2007
expressed as percentage of total length (% TL). Total length is expressed in millimeters. Abbreviations:
N
, number of specimens;
x
, mean;
SD
, standard deviation.
S. bucephalus
|
Holotype
|
Range N =8
|
x
|
SD
|
TL (mm) 550.0 |
430.0-810.0 |
666.0 |
161.8 |
PCL |
75.3 |
74.9-78.1 |
76.8 |
1.1 |
PD2 |
58.5 |
59.0-61.4 |
60.0 |
1.0 |
PD1 |
27.5 |
28.3-29.6 |
28.7 |
0.6 |
SVL |
46.7 |
46.2-49.5 |
47.6 |
1.1 |
PP2 |
44.5 |
43.8-45.5 |
44.6 |
0.6 |
PP1 |
21.1 |
20.0-24.2 |
22.0 |
1.4 |
HDL |
22.7 |
20.8-24.8 |
22.8 |
1.3 |
PG1 |
18.7 |
18.5-20.2 |
19.3 |
0.6 |
PSP |
13.2 |
12.2-14.0 |
13.0 |
0.5 |
POB |
8.1 |
6.8-7.9 |
7.5 |
0.4 |
PRN |
5.0 |
4.5-5.4 |
5.0 |
0.3 |
POR |
9.7 |
9.2-10.9 |
9.7 |
0.5 |
INLF |
4.7 |
4.6-5.2 |
4.8 |
0.2 |
MOW |
8.7 |
7.6-8.8 |
8.2 |
0.4 |
ULA |
2.4 |
2.0-2.6 |
2.3 |
0.2 |
INW |
4.4 |
4.3-5.0 |
4.7 |
0.3 |
INO |
9.5 |
8.0-9.8 |
8.9 |
0.5 |
EYL |
4.9 |
4.5-5.6 |
4.9 |
0.4 |
EYH |
1.8 |
1.3-2.1 |
1.9 |
0.3 |
SPL |
1.3 |
1.2-1.7 |
1.4 |
0.2 |
GS1 |
2.1 |
1.6-2.2 |
2.0 |
0.2 |
GS5 |
2.3 |
2.1-2.5 |
2.3 |
0.1 |
IDS |
22.7 |
21.5-24.7 |
23.2 |
1.1 |
DCS |
9.5 |
8.7-10.3 |
9.6 |
0.5 |
PPS |
20.5 |
17.3-21.4 |
19.9 |
1.2 |
PCA |
24.9 |
23.1-26.3 |
24.4 |
0.9 |
D1L |
14.1 |
13.0-15.2 |
14.4 |
0.6 |
D1A |
12.3 |
10.0-13.8 |
12.3 |
1.1 |
D1B |
8.0 |
8.3-9.6 |
8.9 |
0.5 |
D1H |
9.8 |
8.5-9.8 |
9.4 |
0.5 |
D1I |
6.1 |
4.7-5.8 |
5.5 |
0.4 |
D1P |
9.9 |
5.7-10.2 |
9.1 |
1.4 |
D1ES |
3.5 |
2.7-3.8 |
3.4 |
0.4 |
D1BS |
0.8 |
0.7-0.8 |
0.8 |
0.1 |
D2L |
12.3 |
10.8-13.1 |
11.8 |
0.7 |
D2A |
10.9 |
9.3-11.6 |
10.4 |
0.7 |
D2B |
7.3 |
6.9-8.4 |
7.4 |
0.4 |
D2H |
6.1 |
4.3-6.6 |
5.9 |
0.7 |
D2I |
5.0 |
4.0-4.9 |
4.5 |
0.4 |
D2P |
5.1 |
4.3-6.0 |
5.0 |
0.5 |
D2ES |
4.5 |
3.4-4.6 |
4.2 |
0.5 |
D2BS |
0.8 |
0.7-1.0 |
0.8 |
0.1 |
P1A |
16.4 |
14.9-16.3 |
15.6 |
0.5 |
P1I |
9.1 |
6.7-8.8 |
8.3 |
0.7 |
P1B |
5.4 |
4.8-5.6 |
5.2 |
0.2 |
P1P |
12.4 |
11.5-12.3 |
12.0 |
0.3 |
P2L |
10.9 |
9.8-12.3 |
11.1 |
0.9 |
P2I |
5.9 |
5.2-6.1 |
5.6 |
0.3 |
CDM |
24.2 |
21.7-23.9 |
23.0 |
0.8 |
CPV |
11.9 |
11.2-12.2 |
11.8 |
0.3 |
CFW |
7.4 |
6.5-7.5 |
7.1 |
0.3 |
HANW |
8.2 |
7.0-8.4 |
7.9 |
0.4 |
HAMW |
13.5 |
12.1-13.9 |
13.0 |
0.6 |
HDW |
13.8 |
12.7-14.0 |
13.4 |
0.5 |
TRW |
11.9 |
8.9-13.0 |
11.3 |
1.3 |
ABW |
9.1 |
8.4-11.0 |
9.6 |
1.1 |
HDH |
10.8 |
9.5-11.6 |
10.7 |
0.7 |
TRH |
11.0 |
10.0-14.9 |
11.8 |
1.5 |
ABH |
10.6 |
8.3-13.3 |
10.5 |
1.7 |
CLO |
– |
1.1-3.4 |
2.8 |
0.9 |
CLI |
– |
3.2-6.8 |
5.9 |
1.3 |
FIG. 13. — Upper (
A
) and lower (
B
) teeth of
Squalus bucephalus
Last, Séret & Pogonoski,2007
(MNHN-IC-1997-3662, adult male,795 mm TL) in labial view. Scale bars: 1 mm.
FIG. 14. — Caudal fin of paratype of
Squalus bucephalus
Last,Séret & Pogonoski, 2007
(NMNZ P 34030, adult male, 787 mm TL). Scale bar: 20 mm.
REMARKS
Squalus bucephalus
is a deep-water dogfish shark that occurs in the continental slope between
405-962 m
depth, although it is often caught at depths between 405-600 meters. It is a species with very restrict geographical distribution and whose biology is totally unknown. Females are rarely caught in
New Caledonia
, arousing attention for conservation and fisheries management. Studies on population size and trends, maturation, feeding and reproduction are imperative for threatened assessments of this species.