BIOLOGICAL RESULTS OF THE UNIVERSITY OF MIAMI DEEP-SEA
EXPEDITIONS.
87.
PROFUNDISSIMUS
(PISCES; BROTULIDAE)
FROM THE PUERTO RICO TRENCHl
BASSOGIGAS
JON C. STAIGER
University oj Miami,
Rosenstiel School of Marine and Atmospheric
Science
ABSTRACT
The fifth known specimen of the brotulid species Bassogigas projundissimus (Roule, 1913) is reported from a depth of 8370 m in the Puerto Rico
Trench. It represents the deepest capture of a vertebrate. The specimen is
described and compared with those previously described. The cephalic
la~eralis system is described.
INTRODUCTION
During cruise P-7001 of the R/V JOHNELLIOTTPILLSBURY,four hauls
with a 41-foot (12.5 m) otter trawl were made on the floor of the Puerto
Rico Trench. One of these tows, Station P-1168, yielded a single specimen
of a fish of the family Brotulidae from a depth of 8370 m. The specimen
is a Bassogigas, as defined by Nybelin (1957: 295-303, tables 15 and 16),
and it agrees best with B. projundissimus, as defined by Nybelin (1957:
301-303) and Nielsen (1964: 113-115).
Bassogigas projundissimus was known previously from three specimens
from the Atlantic Ocean and one from the Pacific. The Atlantic specimens
were from PRINCESSE-ALICEStation 1173 (12°07'30"N, 33°32'45"W;
6035 m; 6 August 1901; the holotype), and from Swedish Deep-Sea Expedition stations 329 (9° 38'N, 26° 20'W to 9° 50'N, 26° 30'W; 5600 m;
3 July 1948) and 371 (24° 12'N, 63°23'W to 24°28'N, 63° 18'W; 5850
m; 20 August 1948). The Pacific specimen was from GALATHEAStation
466 (10021'S, 110° 12'E; 7160 m; 6 September 1951; Java Trench).
Nielsen (1964) reviewed the occurrence and distribution of fishes from
hadal depths (deeper than 6000 m). The deepest occurrence of a fish
known at that time was a liparid, Careproctus amblystomopsis Andriiashev,
1955, taken from 7579 m in the Japan Trench. The PILLSBURYspecimen
of Bassogigas profundissimus extends the depth range of fishes down to
8370 m. Of the five recorded occurrences of B. profundissimus, three are
from hadal depths. The overall bathymetric range of the species is 5600
to 8370 m.
Contribution No. 1441 from the University of Miami, Rosenstiel School of Marine and Atmospheric
Science. This paper is one of a series resulting from the National Geographic Society-University of
Miami Deep-Sea Biology Program.
1
1972]
Staiger: Bassogigas profundissimus
27
Bassogigas profundissimus (Roule, 1913)
Material Examined.-UMML
29070; 1 Q, 143.6 mm SL; PILLSBURY
Station P-1168, 19° 42.5' to 43.0'N, 67° 05'W, 21 January 1970, 8370 m,
1430-1830 hours, 41-foot otter trawl, bottom material reduced bluish clay.
The PILLSBURYspecimen of B. profundissimus arrived on deck completely imbedded in a large mass of fine mud. The fish was discovered
when the mass of mud was washed apart in a pan of water. Because the
specimen was insulated from turbulence in the net for part of the tow and
during retrieval, it arrived in fine condition, with all of the fin rays and
much of the fin membranes intact. Unfortunately, the scales were lost,
probably before the animal was buried by the sediment.
General Description.-The
PILLSBURYspecimen is slender, with the maximum depth, measured about midway between the pectoral-fin base and
the anus, approximately one-sixth of the standard length. The head length
is also about one-sixth of the standard length. The pectoral-fin rays are
quite filamentous. Two of the rays, the seventh and eighth, are considerably
prolonged, the seventh being half the standard length of the specimen. The
longest of the two pelvic-fin rays is the outer one, which is half the length
of the head. All eight caudal-fin rays are branched. The longest rays,
numbers two to seven, are slightly shorter than the length of the head.
None of the rays of the dorsal and anal fins appears to be prolonged, nor
is any of them branched. The mouth is quite large, the length of the
maxillary being about two-thirds the length of the head. The eyes are very
small, the eye diameter being about one-twelfth the length of the head.
The skin is transparent, so that the general coloration is that of the
underlying tissues. On the trunk and tail the color is pale yellow-brown,
the yellow coming from the underlying muscle and the brown concentrated
at the margins of the scale pockets. The abdominal area is dark brown,
from the dark peritoneum. The head is also dark brown, especialIy the
skin covering the premaxillary, maxillary, and dentary bones, the branchiostegal membranes, and the lining of the branchial cavity. The pectoral-fin
rays are brown, and brown pigment is present in the fin membranes. The
pelvic-fin rays are also brown, with the pigment most concentrated distally.
The basal portions of the dorsal and anal fins are brown, while their margins
are quite pale. The caudal fin is unpigmented except for a slight amount
of brown at the tips of the fin rays.
The cephalic lateralis system of the PILLSBURYspecimen, illustrated in
Figure 1, consists of lateral, supraorbital, infraorbital, and preoperculomandibular canals on each side of the head, connected by a supratemporal
canal across the top of the head. There are no pores on the supratemporal
canal. The lateral canal terminates in a single pore slightly dorsocaudal
of the dorsal end of the opercular cleft. The lateral canal does not appear
28
Bulletin
of Marine Science
[22(1)
1. Cephalic lateralis system of Bassogigas profundissimus. Pores are
black. Courses of canals are indicated by fine lines connecting pores. Courses
of lines of free end organs are indicated by dotted lines.
FIGURE
to extend onto the trunk. There is a single pore at the anterior end of the
supraorbital canal. It is located just above the upper lip, anterior to the
labial groove connecting the upper lip and the anterior naris. A series of
six pores opens into the infraorbital canal along the pre orbital rim. The
first pore is located slightly anterior to the posterior end of the maxillary
and the sixth is located just posterior to the labial groove. There are eight
pores along the preoperculomandibular canal. The first and second are at
the lower end of the descending portion of the canal, along the posterior
edge of the preoperculum. The third pore is located on the ventral edge of
the preoperculum. The fourth and fifth pores are along the ramus of the
jaw, with the fourth just below the corner of the mouth. The sixth and
seventh pores are a pair, one inside and the other outside the ramus. The
eighth pore is lateral to the mandibular symphysis. The supraorbital, preoperculomandibular, lateral, and supratemporal canals all join at a point
anterodorsal to the dorsal end of the opercular cleft. A series of free end
organs follows the line of the supraorbital canal from above the eye anteriorly to the labial groove. This series is not indicated in Figure 1 because
it lies in a groove that follows the course of the supraorbital canal. A second
1972]
Staiger:
Bassogigas
projundissimus
29
FIGURE2. First branchial arch (from right side) of Bassogigas profundissimus.
line of free end organs extends vertically along the cheek, from just posterior
to the posterior end of the maxillary to the supraorbital canal. A third
series of free end organs lies on top of the head dorsal to the supraorbital
and anterior to the supratemporal canals. This series consists of a line
parallel to the course of the supratemporal canal, with an anterior extension
at each end. These two extensions are parallel to the supraorbital canal. A
fourth series of free end organs occurs along the course of the preoperculomandibular canal from the vicinity of the third pore to the area of the
mandibular symphysis.
The premaxillary, vomerine, palatine, and dentary dentition of the PILLSBURY specimen resembles that described and illustrated for the other specimens. The dentigerous patches on the premaxillaries, dentary, and palatines
are poorly developed and narrow, and the vomerine patch is broadly Vshaped, a characteristic of the genus (Nybelin, 1957: 298). The basibranchial dentition is somewhat different from that described for previous
specimens. The posterior basibranchial tooth-patch on the GALATHEA
(Nielsen, 1964: 155, fig. 3) and Swedish Deep-Sea Expedition (Nybelin,
1957: 297, textfig. 29) specimens is almost circular and its length is only
about one-third that of the anterior tooth-patch. In the PILLSBURY specimen
the posterior tooth-patch is elongate, so that it is nearly as long as the
anterior one.
Figure 2 shows the first branchial arch (from the right side) of the
PILLSBURY specimen. There are four rudimentary rakers on the epibranchial, one long one in the epibranchial-ceratobranchial joint, and eight long
rakers and five rudiments (four on the right side) on the ceratobranchialhypobranchial portion. Alternating with the lower rudiments are five small
dentigerous patches. The gill filaments themselves are not as long as the
width of the gill arch, and form a rather sparse fringe.
The alimentary tract is quite simple. The stomach extends posteriorly
30
Bulletin of Marine Science
[22(1)
about two-thirds the length of the abdominal cavity. The intestine runs
anteriorly about 5 nun from the pyloric region, at the posterior end of the
stomach, and then extends posteriorly straight to the anus. There are no
pyloric appendages. The stomach and intestine were slit open for their
entire lengths and examined, but unfortunately they were empty.
The ovaries are joined into an inverted bowl-shaped organ about 9 mm
long. The organ lies anterodorsal to the genital pore and the anus.
Counts and Measurements.-These
data follow Nielsen (1964: 115, table
1) and are given in his order of presentation to facilitate comparison with
his data.
Standard length: 143.6 mm. Sex: female. Meristic characters: dorsalfin rays, 103; caudal-fin rays, 8; anal-fin rays, 80; ventral-fin rays, 2; pectoral-fin rays, 10; branchiostegal rays, 8; gill rakers on anterior arch, 4 + 1/
8 + 5; vertebrae, 67 (18 + 49); scales in lateral line, ca. 110; scales in
transverse row, 25. Morphometric
characters
(in millimeters):
head length,
30.0 (20.9 per cent SL); depth at dorsal-fin origin, 24.2 (16.9 per cent
SL); depth at caudal-fin origin (minimum depth of Nielsen [1964]), 1.3
(1.0 per cent SL); snout length, 9.1 (6.3 per cent SL); upper jaw length,
16.8 (11.7 per cent SL); horizontal eye diameter, 2.4 (1. 7 per cent SL);
interorbital width, 8.8 (6.1 per cent SL); snout to tip of opercular spine,
29.6 (20.6 per cent SL); snout to anus, 54.0 (37.6 per cent SL); snout
to anal-fin origin, 61.5 (42.8 per cent SL); snout to dorsal-fin origin, 38.9
(27.1 per cent SL); dorsal-fin base, 113.2 (78.8 per cent SL); anal-fin
base, 85.7 (59.7 per cent SL); inner ventral-fin ray, 11.6 (8.1 per cent
SL); outer ventral-fin ray, 15.6 (10.9 per cent SL); longest pectoral-fin
ray, 72.2 (50.3 per cent SL).
Comparison.-A
comparison of these data with the data presented for the
other four specimens of B. profundissimus by Nielsen (1964: 115, table 1)
shows that the PILLSBURY specimen differs noticeably from the others in
three meristic characters: numbers of pectoral-fin rays, vertebrae, and
lateral-line scales. The holotype and the GALATHEA specimen had 15 to 16
pectoral-fin rays, while the PILLSBURY specimen has only 10. The vertebral
count for the GALATHEA specimen was 71 (19 precaudal and 52 caudal),
while the count for the PILLSBURY specimen is 67 (18 precaudal and 49
caudal). The lateral-line scale counts given for the holotype and the
GALATHEA specimen are ca. 140 and ca. 150, respectively, but Dr. Daniel
M. Cohen (personal communication) counted only 125 on the holotype.
The PILLSBURY specimen has ca. 110 lateral-line scales.
As little is known of the range of variation of these characters within
the species, and in other respects the PILLSBURY specimen conforms to the
published descriptions of B. profundissimus, it seems best to consider it as
belonging to that species.
1972]
Staiger: Bassogigas profundissimus
31
There are a few minor differences between the measurements of the
PILLSBURYspecimen and the other four specimens. The snout length of
the PILLSBURYspecimen is 6.3 per cent of SL, while it ranges from 5.1
to 5.4 per cent of SL in the other four. The interorbital width is 6.1 per
cent of SL, while it ranges from 7.0 to 9.3 in the other four. The snout-toanus distance is 37.6 per cent of SL, and ranges from 40.9 to 44.1 in the
others. The distance from snout to dorsal-fin origin is 27.1 per cent of SL
in the PILLSBURYspecimen, and only 23.8 to 24.4 in the other four. In
all other morphometric characters, the figures for the PILLSBURYspecimen
lie within the range of variation of the other four specimens. I do not think
that these differences are meaningful. These are soft-bodied fishes, easily
distorted, and none of the measurements is easily made. When Nybelin
(1957: 302) reexamined the mounted holotype he found several discrepancies between his measurements and those given by Roule (1919). The
head of the PILLSBURYspecimen is flexed ventrally somewhat, and this too
might have some bearing on the differences in measurement.
Discussion.-Bassogigas profundissimus has been figured in the primary
literature three times. In the illustration of the holotype (Roule, 1919:
pI. II, fig. 2), the pectoral-fin rays extend well beyond the anus and the
caudal-fin rays are also prolonged. In the illustration of the GALATHEA
specimen (Nielsen, 1964: 114, fig. 1), the pectoral-fin rays terminate in
advance of the anus, and the caudal-fin rays are not appreciably longer
than the adjacent dorsal- and anal-fin rays. The specimen from Swedish
Deep-Sea Expedition Station 329, illustrated by Nybelin (1957: pI. V,
fig. 4), lacks the pectoral-fin rays, but there is an indication of an elongation
of the caudal-fin rays.
Nybelin (1957: 302) and Nielsen (1964: 114-116) discussed several
characters which they felt exhibited sexual dimorphism. Nybelin (1957:
302) felt that the abdominal cavity of females was longer, to allow more
room for the ovaries. This was reflected morphometrically by a longer
snout-anal-fin measurement and a correspondingly shorter anal-fin base.
Males possess two characters absent in females: a genital papilla and flattened ventral-fin ray tips, with dark-brown borders. Neither the GALATHEA
(Nielsen, 1964: 116) nor the PILLSBURYspecimen strongly supports the
idea that females possess longer abdominal cavities than males. In both
specimens the anal-fin base is 59 per cent of SL. In the two male specimens
the anal-fin bases are 59 and 60 per cent of SL. The snout-anal-fin distances of the GALATHEAand PILLSBURYfemales are 42 and 43 per cent of
SL, while in the two males they are 40 and 42 per cent of SL. The PILLSBURYspecimen does not have a genital papilla, and the tips of the pelvic-fin
rays taper to a point.
The occurrence of Bassogigas profundissimus in the Puerto Rico Trench
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Bulletin
of Marine
Science
[22(1)
is not unexpected. Swedish Deep-Sea Expedition Station 371, the third
record of the species, is from the Nares Abyssal Plain, a level-bottom area
only about 366 kilometers (200 nautical miles) north of the Puerto Rico
Trench. This distance is quite small, considering that the holotype and the
second specimen came from the Cape Verde Basin, and the fourth from
the Java, or Sunda, Trench, in the eastern Indian Ocean.
No hydrographic data were taken in the Puerto Rico Trench in conjunction with the deep trawl tows of Cruise P-7001. During a previous cruise,
P-6902, a Benthos time-depth-temperature servorecorder was lowered to
3000 m over the trench. The temperature profile indicated a decrease from
26.0° C at the surface to 2.9° C at 3000 m. Fuglister (1960: 51) indicated
a temperature of 2.10° C at 6500 m in the Puerto Rico Trench, and a
salinity of 34.837%0.
ACKNOWLEDGMENTS
I wish to thank Dr. C. Richard Robins, Rosenstiel School of Marine and
Atmospheric Science, University of Miami, for suggestions and criticism
of the manuscript, and Dr. Daniel M. Cohen, National Marine Fisheries
Service Systematics Laboratory, U. S. National Museum, for information
on the holotype and subsequent specimens and criticism of the manuscript.
This work was supported by the National Geographic Society-University
of Miami Deep-Sea Biology Program, Dr. Gilbert L. Voss, Principal Investigator, and National Science Foundation ship support grant NSF-GD27252.
SUMARIO
Bassogigas
profundissimus
(PISCES; BROTULIDAE)DE LA FOSA DE
PUERTORIco
Un solo ejemplar de la espeeie de pez brotulido Bassogigas profundissimus (Roule, 1913) fue capturado en la fosa de Puerto Rico a una profundidad de 8370 m. Los datos correspondientes a la captura son: B/I
JOHNELLIOTTPILLSBURYestaci6n P-1168, 19°42.5' a 43.0'N, 67°05'0, 21
de enero 1970, material del fondo arcilla azulosa reducida. Este es el
quinto ejemplar conocido de esta especie. El ejemplar del PILLSBURYdifiere
de los otros en siete caracteres: numero de radios de la aleta pectoral,
vertebras, escamas de la linea lateral, largo del hocico, distancia interorbital, distancia desde el hocico al ano y distancia desde el hocico a la
aleta dorsal. Ninguna de estas diferencias es considerada de significaci6n.
Se describe e ilustra el sistema de la linea lateral cefalica. No se obtuvieron
datos hidrograficos en el momento de la captura, pero Fuglister (1960:
51) ha reportado en la fosa una temperatura de 2.10cC y salinidad de
34.837%0 a 6500 m.
1972]
Staiger: Bassogigas projundissimus
LITERATURE
33
CITED
FREDERICK C.
1960. Atlantic Ocean atlas of temperature and salinity profiles and data from
the International Geophysical Year of 1957-1958. Woods Hole oceanogr. Instn Atlas Ser., 1.
NIELSEN, J~RGEN G.
1964. Fishes from depths exceeding 6000 meters. Galathea Rep., 7: 113-124,
8 figs., 2 tables.
FUGLISTER,
NYBELIN,
ORVAR
1957. Deep-sea bottom fishes. Rep. Swed. deep Sea Exped. Vol. II. Zoology
(20): 247-346, 7 plates, 50 textfigs., 23 tables.
ROULE,
LOUIS
1919. Poissons proven ant des campagnes du yacht Princesse-Alice (18911913) et du yacht Hirondelle 11 (1914). Result. Camp. scient. Monaco, 52: 1-191, 7 plates.