Review of the arrowtooth eel genera Dysomma and Dysommina in Taiwan, with the description of a new species (Anguilliformes: Synaphobranchidae: Ilyophinae)
Author
Ho, Hsuan-Ching
Author
Smith, David G.
Author
Tighe, Kenneth A.
text
Zootaxa
2015
4060
1
86
104
journal article
39199
10.11646/zootaxa.4060.1.12
ca0b84ea-10e9-4bc9-9fa7-e80cf743106b
1175-5326
237500
DCE83F63-6CBE-4166-884F-347DF0BEBB62
Dysomma polycatodon
Karrer, 1983
Fig. 7
;
Table 3
Dysomma polycatodon
Karrer, 1983
:89
(
type
locality: Northwestern
Madagascar
,
15°21'S
,
46°11'E
, depth
170–175 m
).
Robins & Robins, 1989
:250
.
Smith, 1999
:1661
.
Chen & Mok, 2001
:79
.
Specimens examined.
Collected from Daxi fishing port, NE
Taiwan
, bottom trawl: ASIZP 60188 (1 spec.,
453 mm
TL),
15 Oct. 1997
. NMMB-P384 (1, 326),
23 Jan. 1994
. NMMB-P11120 (1, 544),
6 Sep. 2010
. USNM 372011 (1, 362),
12 Sep 1998
. USNM 398475 (1, 384),
10 Sep. 2007
. Collected from Dong-gang fishing port, SW
Taiwan
, bottom trawl: ASIZP 55560 (1, 358),
15 Jan. 1981
. NMMB-P2843 (1, 505),
100 m
,
8 Nov. 2001
. NMMB- P3652 (1,321),
150 m
,
28 May 2012
. NMMB-P9076 (1, 250),
13 Jun. 2008
. NMMB-P11128 (2, 310–333),
13 Sep. 2010
. NMMB-P11129 (1, 400),
13 Sep. 2011
. NMMB-P11132 (1, 365),
6 Sep. 2010
. NMMB-P12070 (1, 550),
18 Feb. 2011
. NMMB-P12625 (2, 372–375),
25 Mar. 2011
. NMMB-P15256 (1, 407),
28 Oct. 2011
. NMMB-P15625 (2, 367–371),
25 Mar. 2011
. NMMB-P16388 (1, 274),
21 Feb. 2012
. NMMB-P17776 (1, 344),
9 Aug. 2012
. NMMB-P17783 (1, 544),
9 Aug. 2012
. NMMB-P18040 (3, 500–600), no date. NMMB-P19278 (1, 260),
10 Nov. 2011
. USNM 398736 (1, 196),
14 Nov. 2009
. USNM 398737 (1, 265),
14 Nov. 2009
. USNM 402447 (5, 275–362),
Nov. 2009
. USNM 410020 (1, 382),
26 Feb. 2011
. USNM 427171 (1, 311),
16 Nov. 2011
. Collected from Shiaoliu-chiu, SW
Taiwan
: NMMB-P3415 (1, 355),
26 Dec. 2003
.
Other localities
.
Philippines
: USNM 344108 (1, 436),
23 Sep. 1995
.
Madagascar
: MNHN 1979–0003 (1, 523),
holotype
,
15°19'58.8"S
,
46°11'2.4"E
,
170–175 m
,
19 Jan. 1979
.
Diagnosis.
Pectoral fin present; dorsal-fin origin anterior tolevel of pectoral fin base, predorsal length 10.0– 12.9% TL; anus anterior, just below pectoral fin, preanal length 15.5–18.2% TL; trunk very short, trunk length 2.4– 3.9% TL; 2 intermaxillary teeth; 3 compound teeth on vomer; 3 or 4 rows of small sharp teeth on upper jaw; single row of 2 large anterior teeth followed by 22–31 small sharp teeth on lower jaw; head pores: IO 4, SO 3, M 6, POP 0 (1 with 1), AD 1 (1with 0); lateral-line pores: predorsal 3–5, prepectoral 5–7, preanal 8–11, and total 65–78, the last at about anterior two-thirds of total length; MVF 8-13-130, total vertebrae 128–133 (1 with 120). Body light grayish to brown dorsally, paler ventrally; posterior half of anal-fin base deep brown, and dorsal and anal fins with white margins.
Remarks.
The
holotype
of this species, collected off
Madagascar
, has 140 vertebrae (
Karrer, 1983
), significantly more than the specimens from
Taiwan
(128–133). One of two specimens in NMMB-P18040 has only 120 total vertebrae. However, no other difference can be observed and the vertebrae appear to be complete. This specimen may represent a different species when more specimens are available.