The First Records of Neocyema (Teleostei: Saccopharyngiformes)
in the Western North Atlantic with Comments on its Relationship
to Leptocephalus holti Schmidt 1909
Shannon C. DeVaney, Karsten E. Hartel, and Daphne E. Themelis
Northeastern Naturalist, Volume 16, Issue 3 (2009): 409–414
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2009 NORTHEASTERN NATURALIST 16(3):409–414
The First Records of Neocyema (Teleostei: Saccopharyngiformes)
in the Western North Atlantic with Comments on its Relationship
to Leptocephalus holti Schmidt 1909
Shannon C. DeVaney1,2,*, Karsten E. Hartel3, and Daphne E. Themelis4
Abstract - Two new specimens of the rare deep sea eel genus Neocyema were collected
in the western North Atlantic in June 2006 and September 2008. Previously the
genus was known only from the two type specimens, collected in the South Atlantic
in 1971. External morphology and osteology indicate that the new specimens probably
belong to the described species Neocyema erythrosoma. Their capture in the
North Atlantic provides support for the hypothesis that Neocyema is the adult form
of the enigmatic larva Leptocephalus holti.
Introduction
A bright orange leptocephalus-like eel (Fig. 1) was collected during a
NOAA National Marine Fisheries Service deepwater biodiversity survey
in the vicinity of Bear Seamount at 39°51'N, 67°02'W on 17 June 2006. Two
years later, another small orange eel (Fig. 2) was collected during a Canadian
Department of Fisheries and Oceans research cruise to the Gully Marine Protected
Area at 43°45'N, 58°48'W on 5 September 2008. These two specimens
(MCZ [Museum of Comparative Zoology, Harvard University] 165900, 91
mm SL; ARC [Atlantic Reference Centre, Huntsman Marine Science Center,
St. Andrews, NB, Canada] 28117, 88 mm SL) are very similar to Neocyema
erythrosoma Castle 1977 (Fig. 3), which was described and previously known
from two specimens collected in the central and eastern South Atlantic in 1971.
The current specimens represent the third and fourth confirmed records of the
genus Neocyema, and the first records from the western North Atlantic.
The family Cyematidae (Actinopterygii: Saccopharyngiformes) is composed
of two species described from adult material: Cyema atrum Günther
1878, and Neocyema erythrosoma. Both Cyema and Neocyema adults are
short-bodied and laterally compressed, with long, delicate jaws, small teeth,
and small eyes. Cyematids were once placed in the family Nemichthyidae
(snipe eels) leading to their common name, the “bobtail snipe eels.” However,
several authors (Bertin 1937, Raju 1974, Robins 1989) have pointed out that
cyematids are morphologically closest to saccopharyngiform (gulper) eels.
1Department of Ecology and Evolutionary Biology and Biodiversity Institute, Natural
History Museum, University of Kansas, 1345 Jayhawk Boulevard, Lawrence,
KS 66045. 2Current Address - Natural History Museum of Los Angeles County, 900
Exposition Boulevard, Los Angeles, CA 90007. 3Museum of Comparative Zoology,
Harvard University, 26 Oxford Street, Cambridge, MA 02138. 4Department of Biology,
Mount Saint Vincent University, Halifax, NS, B3M 2J6, Canada.*Corresponding
author - sdevaney@nhm.org.
410 Northeastern Naturalist Vol. 16, No. 3
The genus Neocyema is particularly notable for its vibrant red-orange
color and apparently paedomorphic condition. In the species description,
Castle (1977) indicated that the holotype and paratype were originally
thought to be leptocephali or metamorphic specimens, until his further analysis
revealed them to be adults. Similarly, when the first of the new specimens
(MCZ 165900) was originally collected, the general first impression of the
scientific party (which included S.C. DeVaney and K.E. Hartel) before it was
identified as a Neocyema, was that it was a transforming larva. Like Castle
(1977), we note small eggs in long, paired ovaries in our specimens.
The new specimens come from a relatively well-sampled region of deep
ocean. Recent work (Hartel et al. 2008, Moore et al. 2003) documents 631
fish species known to occur below 200 m in an area off greater New England.
These records are the result of thousands of trawls made principally by the
Woods Hole Oceanographic Institution and by the National Marine Fisheries
Service. The Canadian Department of Fisheries and Oceans has made
several hundred midwater tows over the continental slope near the Scotian
Shelf, capturing more than 260 mesopelagic species (D.C. Themelis, unpubl.
data). The fact that these specimens are the first records of Neocyema in the
western North Atlantic underscores the rarity of the genus.
Figure 3. Holotype of Neocyema erythrosoma, reproduced from Castle (1977).
Figure 1. New specimen of Neocyema (MCZ 165900). Stomach exposed due to net
damage to ventral body wall.
Figure 2. New specimen of Neocyema (ARC 28117).
2009 S.C. DeVaney, K.E. Hartel, and D.E. Themelis 411
Materials and Methods
The first new specimen of Neocyema (MCZ 165900) was collected by
the NOAA ship R/V Delaware II in an International Young Gadoid Pelagic
Trawl (IYGPT) midwater trawl fished open to 2284 m over an average bottom
depth of 3424 m. The second new specimen (ARC 28117) was collected
by CCGS Wilfred Templeman in an IYGPT midwater trawl fished open to
1620 m over an average bottom depth of 2500 m. Both specimens were photographed
and fixed in formalin shortly after capture. In order to preserve
the integrity of these rare specimens, they were not cleared and stained;
instead, osteology was examined via X-ray imaging. Digital images and
X-rays of the intact holotype and the cleared and stained paratype of Neocyema
erythrosoma, as well as specimens and images of Cyema atrum, were
examined for comparison to the new specimens. Specimens Examined:
were Cyema atrum - MCZ 47843, MCZ 52122, MCZ 60589, MCZ 60592,
MCZ 100870, MCZ 144806, MCZ 148419, MCZ 165935. Neocyema sp.
- MCZ 165900, ARC 28117. Neocyema erythrosoma - ISH (Institut für
Seefischerei Hamburg collection, now at Universität Hamburg ) 1194-1971
(holotype), ISH 956-1971 (paratype; cleared).
Discussion
Identification of the specimens
Castle (1977) provided a thorough diagnosis of Neocyema erythrosoma
(Table 1). Like the type specimens, the new specimens were bright red-orange
at the time of capture, fading to white in alcohol. Myomeres are easily visible
through the transparent skin. The new specimens also have the same extreme
skeletal reductions known from the type specimens. In these fishes, both the
opercular series and the pectoral girdle are absent, and only a single branchial
Table 1. Neocyema data from Castle (1977), ARC 28117, and MCZ 165900. Leptocephalus holti
data from Smith and Miller (1996).
Neocyema Leptocephalus holti
Holotype Paratype MCZ ARC Species 1 Species 2 Species 3
Total myomeres 108 101 105 105 99–117 108–130 104–115
Pre-vent myomeres 50 47 50 46 45–65 65–75 54–57
Standard length (mm) 140 160 91 88
Branchial arch 1 1 1 1
Dorsal rays 111 114 115 115
Anal rays 75 85 79 77
%SL
Head 16.2 19.4 21 20.2
Snout 5.8 4.4 8.1 8.2
Eye 0.4 0.5 0.4 1.3
Mouth 9.3 7.5 13 13.5
Pectoral 2.9 1.9 Damaged 2.9
Predorsal 64.9 66.5 64.3 61.4
Snout–Anus 64.2 63.9 62.7 63.1
P1 depth 6.1 6.6 10.1 8.4
Anus depth 8.0 10.8 11.3 12.4
412 Northeastern Naturalist Vol. 16, No. 3
arch is present. The long upper jaws are formed by the maxillae (interpreted as
the pterygoid by Robins [1989]), and the lower jaws by the dentaries; neither
premaxillae nor articular bones are present. Among the differences between
the new specimens and the types are a relatively longer head, snout, and
mouth; however, these and other differences may be because the new specimens
are 35–45% smaller than Castle's specimens. The eyes of the Canadian
specimen seem more oval than the other specimens and are angled at about 45°
relative to the upper jaw. The longest measurement of the eye in this specimen
is 0.9% SL, and the shortest measurement is 0.5% SL.
Leptocephalus holti connection
Schmidt (1909) described a distinctive leptocephalus from the northeastern
Atlantic as Leptocephalus holti, but he did not link it to any known adult.
Sixty-five years later, Raju (1974) described a similar larva from the Pacific,
noting its similarity to, yet distinctness from the known larva of Cyema atrum.
Both L. holti and the larva of C. atrum have the v-shaped myomeres, elongate
suspensorium, and looped intestines typical of saccopharygiform leptocephali;
however, L. holti and the C. atrum larva share several characters that
distinguish them from other saccopharyngiform larvae, including an elongate
snout, only 2–4 intestinal loops, large eyes, and distinctive lateral pigment patterns
(Raju 1974, Smith and Miller 1996). Given the morphological evidence,
Raju (1974) was "compelled to relate [L. holti] to an unknown species of the
family Cyemidae." Four years later, when Castle (1977) described the second
cyematid species, Neocyema erythrosoma, he discussed the possibility that
it might be the adult form of L. holti. Smith (1989) expressed the same idea,
but both authors considered the link inconclusive, largely because adult Neocyema
specimens lack the lateral pigment seen in L. holti. Furthermore, the
known distribution of Castle's Neocyema specimens was from 37°S to 39°S
in the Atlantic, which was over 5000 km from the closest known L. holti in the
Pacific and northern Atlantic.
Smith and Miller (1996) reviewed new material of Leptocephalus holti,
adding 47 additional specimens. They concluded that there were three species
or species groups within the material and described each in some detail.
The new specimens revealed that most Atlantic L. holti lack lateral pigment,
thereby removing one of the obstacles to linking this leptocephalus to Neocyema.
The other major obstacle can be surmounted based on the Neocyema
specimens presented herein, as they were collected close to the known localities
of all three forms of L. holti (Fig. 4).
There is now little doubt that Leptocephalus holti are the larvae of Neocyema.
However, the question that remains is which of the three larval forms
can be linked to any of the four adult specimens of Neocyema. Smith and
Miller's species 2, which includes Schmidt's (1909) holotype, seems to be
the most highly pigmented form, and therefore, the least likely. Smith and
Miller’s L. holti species 1 seems to be the closest to the known Neocyema
specimens based on myomeres (Table 1); however, myomere counts overlap,
and we cannot be sure which of the species currently included under the
name L. holti should be linked to known adults of Neocyema.
2009 S.C. DeVaney, K.E. Hartel, and D.E. Themelis 413
Summary
It is clear that the new specimens are Neocyema, making them the third
and fourth known records of the genus and the first from the North Atlantic.
A possible fifth specimen is discussed by Mead (1964), who noted "the
capture of a leptocephalus or larval stage of a deep sea eel, which is bright
orange-red in color" during a 1964 Indian Ocean expedition. The description
strongly resembles a Neocyema; however, no catalog number for the specimen
is given, and to date the specimen has not been found.
Given the small number of Neocyema specimens and the relatively minor
differences between the new specimens and the types of N. erythrosoma, we
do not presently consider the new specimen to be a new species of Neocyema.
However, as Smith and Miller (1996) identified three species or species
groups of L. holti, which we now assert should be recognized as a larval form
of Neocyema, we might expect that there are at least two additional species
Figure 4. Known localities of Neocyema and Leptocephalus holti in the Atlantic: type
specimens of N. erythrosoma (triangles), Neocyema new records (stars), and Leptocephalus
holti (circles). Localities based on ARC and MCZ specimen data and literature.
414 Northeastern Naturalist Vol. 16, No. 3
of Neocyema waiting to be described. Finally, it should be noted that, if we
are correct in linking Neocyema with L. holti, the species Neocyema erythrosoma
Castle 1977 may more correctly be called Neocyema holti (Schmidt
1909), depending on which of the species of L. holti is definitively associated
with this adult.
Acknowledgments
We wish to thank James E. Craddock, David G. Smith, C. Richard Robins, and two
anonymous reviewers for useful comments on the manuscript. Ralf Thiel and Irina Eidus
generously provided digital images and X-rays of the type specimens of Neocyema
erythrosoma from the fish collection at Universität Hamburg. Andrew Williston (MCZ)
produced Figure 1 and 4; Andrew Cogswell (BIO) produced Figure 2. This work was
supported in part by a grant from the W.M. Keck Foundation to the program in Molecular
Systematics and Evolution at the Natural History Museum of Los Angeles County.
Finally, we thank Chief Scientists Michael Vecchione and Trevor Kenchington, the scientific parties, and the officers and crews of the R/V Delaware II during the 2006 Deepwater
Biodiversity Survey and the CCGS Wilfred Templeman during the 2008 Survey
of the Gully MPA.
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