Review of the hagfishes (Myxinidae) from the Galapagos Islands, with descriptions of four new species and their phylogenetic relationships
Author
Mincarone, M. M.
Author
Plachetzki, D.
Author
McCORD, C. L.
Author
Winegard, T. M.
Author
Fernholm, B.
Author
Gonzalez, C. J.
Author
Fudge, D. S.
text
Zoological Journal of the Linnean Society
2021
192
453
474
journal article
0024-4082
C4F4F7F9-C496-4F28-AF92-0B317DC0EBEF
MYXINE GREGGI
SP. NOV.
GREGG’ S HAGFISH
(
FIGS 1
,
2F
,
4A
,
5
,
6D; TABLES
4–6)
Z o o b a n k r e g i s t r a t i o n. u r n: l s i d: z o o b a n k. org:act:
309DFFDD-9C79-42F6-AB51-4B43E1BAFB6C
Holotype
:
SIO
19-82, 408 mm
, off NE
Santa Cruz
Island
,
00°30’57.68”S
,
90°10’17.90”W
,
688 m
depth
,
Valeska Yamile
, sta. G24,
baited trap
,
Douglas Fudge
et al
.,
11 June 2019
, 07:59–11:10 h.
Figure 4.
Fresh specimens of
Myxine
from Galapagos: A,
Myxine greggi
(holotype, SIO 19-82, 408 mm TL); B,
Myxine martinii
(holotype, SIO 19-85, 381 mm TL); C,
Myxine phantasma
(holotype, SIO 19-86, 510 mm TL). Scale bars: 5 cm.
Paratypes
:
MCCDRS 9404
,
11
(
293-445 mm
) and
SIO 19–83
,
1
(
515 mm
), taken with the
holotype
.
MCCDRS 9399
COI,
16S
, 1 (
457 mm
), off NE
Santa Cruz
Island
,
00°29’21.27”S
,
90°10’22.48”W
,
789 m
depth
,
Valeska Yamile
,
baited trap
,
Douglas Fudge
et al
.,
29 May 2019
, 10:16–11:37h.
MCCDRS 9401
COI,
16S
, 10 (
181–485 mm
) and
SIO 19-84
COI,
16S
, 1 (
437 mm
), off north-eastern
Santa Cruz
Island
,
00°29’46.47”S
,
90°12’00.73”W
,
815 m
depth
,
Valeska Yamile
, sta. G5,
baited trap
,
Douglas Fudge
et al
.,
29 May 2019
, 09:21–12:39h.
Diagnosis:
Myxine greggi
differs from all congeners, except
M. affinis
Günther, 1870
and
M. australis
Jenyns, 1842
from southern South America,
M. glutinosa
Linnaeus, 1758
from the eastern North Atlantic and Mediterranean,
M. limosa
Girard, 1859
from the western North Atlantic,
M. hubbsi
Wisner & McMillan, 1995
from the eastern Pacific,
M. hubbsoides
Wisner & McMillan, 1995
from
Chile
,
M. jespersenae
Møller
et al.
, 2005
from
Greenland
and
Iceland
,
M. knappi
Wisner & McMillan, 1995
from southern
Argentina
,
M. kuoi
Mok, 2002
from
Taiwan
,
M. mcmillanae
Hensley, 1991
from the Gulf of Mexico and Caribbean Sea,
M. paucidens
Regan, 1913
from
Japan
,
M. sotoi
Mincarone, 2001
from southern
Brazil
, and
M. martinii
from the Galapagos, by having six pairs of gill pouches and a 2/2 multicusp pattern of teeth.
Myxine greggi
differs from these congeners by having: 34–40 total cusps (vs.
30–32 in
M. kuoi
,
42–88 in
M
.
mcmillanae
and
26 in
M. paucidens
); 22–26 prebranchial pores (vs. 30–
31
M.
hubbsoides,
28–37 in
M. jespersenae
,
30–38 in
M. knappi
and
28–38 in
M. sotoi
); 58–66 trunk pores (vs.
68–71 in
M. hubbsoides
and
52–54 in
M. martinii
); 91–102 total pores (vs.
111–116 in
M. hubbsoides
and
107–121 in
M. jespersenae
); and by having one single conspicuous nasal-sinus papilla in the mid-dorsal surfaceofthenasalsinus(vs.twobilaterallysymmetrical nasal-sinus papillae in
M. jespersenae
).
Myxine greggi
can be also distinguished from the congeners with sixgill pouches by its colour pattern (body dark brown with white head vs. body entirely pigmented, without white head, in
M. affinis
,
M. australis
,
M. hubbsoides
,
M. knappi
,
M. kuoi
and
M. paucidens
).
Myxine greggi
can be further distinguished from
M. hubbsi
by having a well-developed ventral finfold [
3–7 mm
high vs. vestigial to low (
1–2 mm
high)] (
Hensley, 1991
;
Wisner & McMillan, 1995
; Mincarone, 2001; Mok, 2001, 2002;
McMillan & Wisner, 2004
;
Møller
et al.
, 2005
).
Description:
Body elongated, subcylindrical at prebranchial and branchial regions, laterally compressed at trunk and strongly compressed at tail. Rostrum triangular with rounded tip. One single conspicuous nasal-sinus papilla in the mid-dorsal surface of the nasal sinus. Eyespots absent. Three pairs of barbels on head: first two about equal in size (0.6– 1.4% TL) and adjacent to opening of nasopharyngeal duct; third pair longer (1.0–1.9% TL) and immediately adjacent to mouth. Ventral finfold well developed (
3–7 mm
high), beginning within anterior 10% of trunk, extending backward to the cloaca. Caudal finfold thin, rounded, beginning immediately posterior to edge of cloaca, extending around tail to dorsal surface, ending about over cloaca.
Body proportions (in percentage of TL; description of the
holotype
followed by range of
paratypes
in brackets): prebranchial length 25.7 (23.2–28.3); preventral length 27.5 (24.9–31.1); trunk length 62.3 (56.9–64.8); tail length 12.0 (8.7–13.9); body width at PCD 2.5 (2.6–3.6); body depth at PCD 3.6 (3.3–4.4); body depth including VFF 5.4 (3.3–5.5); body depth excluding VFF 3.7 (2.9–5.0); body depth at cloaca 3.4 (2.6–4.3); tail depth 4.2 (2.9–4.8).
Counts (description of the
holotype
followed by range of
paratypes
in brackets): multicusp pattern 2/2; anterior unicusps 6 (6–8); posterior unicusps 7 (7–8); total cusps 34 (34–40). Prebranchial pores 24 (22–26); trunk pores 66 (58–66); tail pores 10 (9–12); total pores 100 (91–102).
Six pairs of gill pouches, with efferent branchial ducts on either side combined into a single external gill aperture posterior to the gill pouches. Gill aperture on the left side confluent with the pharyngocutaneous duct aperture. Dental muscle overlies the first pair of gill pouches. Ventral aorta not branched.
Colour (in life): body dark brown, its dorsal region lighter than ventral (more evident in juveniles); head white, becoming gradually darker backwards; mouth and barbels white; gill apertures with white margin; ventral finfold the same colour as or even darker than body; caudal finfold the same colour as body (
Fig. 4
). Colour in alcohol similar to that described for live specimens.
Distribution and habitat:
Galapagos Islands
: known from
25 specimens
collected in three stations off northeastern
Santa Cruz
Island, between 688 and
815 m
depth (
Fig. 1
).
Etymology:
This species is named for John Gregg, founder and president of the Western Flyer Foundation. John is an ardent supporter of marine biology research and a hagfish enthusiast. He joined the team during part of the
Galapagos
expedition and was on the boat when the specimens were collected.