new pogonophora from the northeast pacific ocean
TRANSCRIPT
New Pogonophora from the northeast Pacific Ocean
EVE C. SOUTHWARD Marine Biological Laboratory, Citadel Hill, Plymouth, England
Received January 14, 1969
SOUTHWARD, E. C. 1969. New Pogonophora from the northeast Pacific Ocean. Can. 3. Zool. 47: 395-403. Five species of Pogonophora have been found in collections of benthos from depths of 200 to 2680
meters off the coast of British Columbia, Canada. They include two species already known from the Pacific, Polybrachia canadensis and Siboglinum pusillum; a new species of Lamellisabella, and a new species of Siboglinum. The fifth species is probably another new species of Siboglinum, but the specimens are not sufficiently complete for definite determination.
Introduction The species described here were collected by
Dr. D. B. Quayle of the Fisheries Research Board of Canada during surveys of bottom- living invertebrates off the west coast of British Columbia in 1964-1968. The locations of the samples containing Pogonophora are Listed in Table I: all but one are from depths between I840 and 2675 m. The exception is sample 66-67, taken from a depth of 220-350 rn in Tasu Inlet, Queen Charlotte Islands, which contained a great many empty tubes and only a few living pogonophores. The samples of pogonophores from the deep-water stations consisted mainly of inhabited tubes.
Descriptions FAMILY Siboglinidae
Siboglinum pusillum IVANOV
S. pusillum Ivanov 1960, 1963 Material-About 700 animals. Occurrence-Stations 63-207, 63-208, 65-37,
65-42, 65-47, 65-64. Depth range-1840 to 2675 m. Types-Representative specimens are de-
posited in the British Museum (Natural History); the National Museum of Canada, Ottawa; and the Smithsonian Institution, Washington D.C., U.S.A.
Description-This is a very small species, with a narrow, brown-ringed tube. The forepart of the body is cylindrical, about 7 or 8 times as long as broad, and ends in a rounded cephalic lobe (Fig. 1, B). The tentacle bears a semidouble row of small pinnules (Fig. 1, D). There are two transverse grooves on the forepart, the first of which is at the level of the tentacle base and the second is a little farther back (Fig. 1, A, B, C).
Both are deepest on the ventral side, and shallow or even absent on the dorsal side. The colorless bridle keels are fused ventrally but separate dorsally (Fig. 1, A, B). There is a small patch of opaque, granule-containing epidermis just behind the bridle. The metameric papillae of the trunk are in two single rows of about 36 to 60, without plaques. Mature adults have three girdles, the first two close together (Fig. 1, G), and the third a long way farther back (2.0 to 4.5 mm), but juveniles have only two girdles (Fig. 1, I). The first juvenile girdle is made up of two half hoops, which must become separated during later growth, while at the same time the part between them and the posterior girdle elongates greatly. This may well be the way in which the three-girdle state develops in those other species of Siboglinum which have it. The toothed platelets of the girdles are mostly about 13 p long, but range from 9 to 17 y. The teeth of the anterior group are unusually small. The spermatophores are 95 to 120 y long. The postannular part of the trunk bears small dorsal shields and associated rows of one to three papillae, with bar-shaped plaques. The tube has a colorless anterior section with a wrinkled surface but no segments. The wrinkled surface continues down over more than half the tube. The brown rings, which extend over most of the tube, are wider than those of the other Sibo- glinum species found in the same samples, and are separated by wider interspaces (Fig. 1, J). The posterior part of the tube has a smooth surface and yellow-brown rings which are often split into doublets (Fig. 1, K).
Measurements-Tentacle, maximum length 8 mm; forepart, length 0.75 to 1.2 mm, diameter 0.082 to 0.105 mm; preannular region of trunk, length 9 to 23 mm; tube, diameter 0.12 to 0.135 anterior, 0.105 posterior.
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CANADIAN JOURNAL OF ZOOLOGY. VOL. 47. 1969
TABLE I Station list
Pogonophora
Station No. No. Position Depth Date Species animals
10. ix .64 P. canadensis 740 S. vancouverensis 1OOO S. pusillurn 100 Siboglinurn sp. 1
10.ix.64 P. canadensis 200 L. coronata 2 S. vancouverensis 100 s. pusillurn 1 S. sp. 1
3.viii.65 P. canadensis 220 L. coronata 17 S. vancouverensis 13 S. pusillurn 4
4.viii.65 P. canadensis 225 L. coronata 24 S. vancouverensis 20 S. pusillurn 8
5.viii.65 P. canadensis 1 S. vancouverensis 3 S. pusillurn 600
.viii.65 S. pusillurn 45 s . SP. Empty
tubes 66-67 52O45' N 220-350 m 16.x.66 P. canadensis 35
132"06' W
Discussion-When compared with Ivanov's description (1963) of S. pusillum the Canadian specimens agree well in most characters, except that they have three girdles instead of two, a groove around the tentacular region of the forepart, and a colorless bridle instead of a brownish one. Individual variation may ac- count for the extra groove on the forepart, which seems to vary a good deal in its depth and extent. The third girdle is such a very long way behind the other two that in Ivanov's rather fragmentary specimens it could easily have been lost or overlooked. Professor Ivanov has very kindly lent me a specimen of S. pusillurn (lacking the girdle and postannular regions) from his original material, and it strongly resembles the Canadian specimens. It has a pale yellow bridle, not brown, so there is certainly some variation in this character, and the Canadian specimens need not be excluded because of their colorless bridles. In view of all the similarities, especially of the toothed plate- lets, and the tubes, the Canadian specimens can be assigned definitely to S. pusillum Ivanov.
Further distribution-Northwest Pacific, 49' N, 155" E, depth 5529 m (Ivanov 1960). S. veleronis Hartman (1961) seems to be very similar to S. pusillurn, but it is not possible to tell from the original description if it is the same species.
Siboglinum vancouverensis SP. NOV. Material-About 1 100 animals. Occurrence-Stations 63-207, 63-208, 65-37,
65-42, 65-47. Depth range-1840 to 2400 m. Types-Holotype in the British Museum
(Natural History), No. 1969.3.3.1; paratypes in the National Museum of Canada and the Smith- sonian Institution.
Description-This is another small species inhabiting a brown-ringed tube. The forepart of the body is 9 to 10 times as long as broad, with a longer cephalic lobe than S. pusillurn (Fig. 2, A, B). The tentacle is comparatively thick and bears two close-packed rows of thin pinnules, which give it a bushy appearance (Fig. 2, C). Just behind the tentacle base there is a com- plete groove around the forepart, and a second
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SOUTHWARD: NEW POGONOPHORA FROM THE PACIFIC
FIG. 1. Siboglinum pusillurn. A, forepart of body, ventral view; B, forepart, dorsal view; C, anterior end, side view; D, part of tentacle; E, spermatophore; F, toothed platelet; G, H, girdles of adult; I, girdles of juvenile; J, middle part of tube; K, posterior part of tube. gl , g2, g3, first, second, and third girdles.
incomplete groove close behind it (Fig. 2, A, B). Frequently there is a slight transverse groove in front of the tentacle base (Fig. 2, A). A median ventral furrow extends for a short distance in front of the bridle (Fig. 2, B). The bridle keels are yellow or yellowish brown and fuse ventrally, but dorsally they are separated by a very small gap (Fig. 2, A, B). There are two areas of granular, opaque epidermis be- hind the bridle, visible in some but not all specimens (Fig. 2, A, B). The forepart is divided from the trunk by a fairly deep groove (Fig. 2, A). The metameric region of the trunk bears two rows of 50 to 60 papillae, without plaques. There are only a few small papillae on the long region between the metameric papillae and the
girdles. The three girdles are single or semi- double rows of narrow platelets. The first two girdles lie close together (Fig. 2, D), as in S. pusillurn, with the third lying 1.5 to 2.0 mm farther back. The platelets are 15 to 18 p long and have equal anterior and posterior groups of teeth (Fig. 2, F). The rather stout spermatophores are 180 to 220p long (Fig. 2, G). The post- annular region has small dorsal shields and rows of three ventral papillae. The tube is intermediate in size between those of the other two Sibo- glinum species described here. The surface is smooth and the anterior end, the first part of which is colorless, is divided into long segments (0.75 to 1.2 mm), for as much as 15 mm. The greater part of the tube is not segmented and
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CANADIAN JOURNAL OF ZOOLOGY. VOL. 47, 1969
FIG. 2. Siboglinum vancouverensis. A, forepart of body, laterodorsal view; B, anterior end, ventral view; C , part of tentacle; D, first and second girdles; E, third girdle; I?, toothed platelet; G, spermatophore; H, anterior part of tube, showing one segment; I, J, parts of middle region of tube; K, L, parts of posterior region of tube.
many of the specimens have lost the segmented part. Narrow yellow-brown rings develop after the first few segments and there are usually 15 to 18 per segment (range 9 to 19) (Fig. 2, H). The middle part of the tube has wider rings and narrower interspaces (Fig. 2, I, J), while the posterior part has pairs (doublets) of narrow rings (Fig. 2, K, L).
Measurements-Tentacle, length 5 to 8 mm; forepart, length 1.3 to 1.5 mm, diameter 0.13 to 0.15 mm; preannular part of trunk, length 44 to 46 mm; tube, diameter 0.16 to 0.18 mm.
Discussion-This species is, in many ways, similar to S. fedotovi Ivanov (1963), especially in the very long tube segments, the two rows of pinnules on the tentacle, the size and shape
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SOUTHWARD: NEW POGONO IPHORA FROM THE PACIFIC
of toothed platelets, and the size and shape of the spermatophores. However, S. fedotovi is larger than S. vancouverensis, with its tube diameter of 0.25 mm and forepart diameter of 0.2 mm, and the annular grooves on the forepart are dif- ferently arranged. It also has the bridle nearer the front end than does S. vancouverensis, and has more metameric papillae. There are three other PacXc species of Siboglinum with narrow, segmented tubes (S. variabile, S. pinnulatum, and S. macrobrachium; see Ivanov 1963 for descriptions), but these are easily distinguished from S. vancouverensis, since they all have fewer than 10 rings per segment.
The new species has been named Siboglinum vancouverensis to commemorate its discovery near Vancouver Island.
Siboglinum SP. Material-Two animals and some empty
tubes. Occurrence-Stations 63-207, 63-208, 65-64. Depth range-1840 to 2675 m. Description-The cylindrical forepart is 5 to
6 times as long as broad, with a shallow post- tentacular groove on the ventral side. The narrow tentacle has two rows of pinnules. The pale yellow or colorless bridle keels fuse ventrally and touch dorsally. There is a narrow belt of granule-containing epidermal cells behind the bridle, incomplete on the dorsal side. There are 32 to 35 pairs of metameric papillae but no group of enlarged papillae. The two girdles are single rows of platelets 0.7 mm apart. The platelets are about 13 p long. Both specimens are immature. The anterior ends of the tubes are missing. The tube surface is smooth, the rings are rather narrow, and towards the pos- terior ends some of them are split, forming pairs of rings.
Measurements-Tentacle, length 7 mm; fore- part, diameter 0.1 5 to 0.18 mm, length 0.97 mm; preannular region, length 7.5 mm; tube, dia- meter 0.18 to 0.195 mm.
Discussion-These specimens, with their in- complete tubes and possibly incomplete girdle region cannot be compared very well with other species. The tubes are much larger than those of S. pusillum and the forepart is shorter than that of S. vancouverensis. In view of their in- completeness and immaturity it seems advisable to leave the species unnamed for the moment.
Polybrachia canadensis (IVANOV)
Heptabrachia canadensis Ivanov 1962, 1963 ; Polybrachia canadensis, Southward 1969.
Material-About 1400 animals and many empty tubes.
Occurrence-Stations 63-207, 63-208, 65-37, 65-42, 65-47, 66-67.
Depth range-220 to 2400 m. Types-Representative specimens are de-
posited in the British Museum, the National Museum of Canada, and the Smithsonian Institution.
Description-The description of Heptabrachia canadensis by Ivanov was based on one immature specimen. It fits the young stages of the species found in the Canadian collections, but since the adults have the characteristics of the genus Polybrachia, the species has been transferred to this genus and redescribed (Southward 1969). Since the adults and growth have already been described, only a short account is given here. Adults have 20 to 40 tentacles, and very rarely as many as 49. The forepart is from 4 to 7 times as long as broad, with two to four annular grooves in front of the bridle. The brown bridle keels touch without fusing on the ventral side and are separated by a gap on the dorsal side. There are 20 to 23 pairs of metameric papillae, each tipped with a plaque 27 to 37 p across. There is a group of from 15 to 40 en- larged papillae. The two girdles are made up of from two to five rows of toothed platelets, the number of rows increasing with the size of the animal. The platelets are 15 to 20 p long. The postannular papillae are in rows of about nine. The spoon-shaped spermatophores are 400 to 450 p long. The tubes of adults are dark brown at the front end, paling to light brown in the middle and white or straw color posteriorly. The anterior part is segmented and ringed, the middle part has rings only, and the posterior part has neither. Each segment overlaps the one in front slightly, and there are three or four rings on each segment.
Measurements-Tentacles, length 6 to 16 mm; forepart, length 1.9 to 3.4 mm, diameter 0.33 to 0.61 mm; length of preannular region 20 to 100 mm; tube, anterior diameter 0.4 to 0.82 (rarely 1.0 mm), middle diameter (unsegmented part) 0.3 to 0.4 mm.
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CANADIAN JOURNAL OF ZOOLOGY. VOL. 47, 1969
FIG. 3. Lamellisabella coronata. A, tentacular crown, ventral. view; B , inside view of part of crown; C, outer sides of two tentacles ; D, transverse section of tentacle. ci, c~lia; s, splne ;pi, plmule;pl, plate; t, tentacle.
Growth-Juvenile specimens have only one or two tentacles, and their limp, whitish tubes are unringed. As the animal grows in length, more tentacles are developed and rings appear on the tube. This results in a "Heptabrachia" stage which has up to 10 tentacles, the full comple- ment of metameric papillae and plaques, but poorly developed annular grooves on the fore- part and no tube segments. This is the stage described by Ivanov (1962). Animals begin to mature as they grow larger and at the same time they start to lay down segments at the front end of the tube (see Southward 1969).
FAMILY Lamellisabellidae Lamellisabella coronata SP. NOV.
Material--43 animals. Occurrence-Stations 63-208, 65-37, 65-42. Depth range-1 830 to 2400 m. Types-The holotype is deposited in the Bri-
tish Museum (Natural History) No. 1969.3.3.2.;
paratypes in the National Museum of Canada and the Smithsonian Institution.
Description-The most obvious feature of this species is the golden-brown crown of tentacles, quite unlike the tentacles of other pogonophores. The tentacles are arranged side by side, forming a cylinder with pinnules almost filling the lumen (Fig. 3, A, B). There are from 20 to 35 tentacles; they adhere fairly strongly to one another with the help of a sticky se- cretion. The basal 2 to 3 mm of the crown is whitish in fixed specimens and the outer parts of the tentacles are covered with a thick cuticle. The top part of the crown is covered with golden scales, 75 to 100 p long, each with an anterior spine, arranged in two rows along each tentacle (Fig. 3, C) and apparently developed from the thick cuticle (Fig. 3, D). The spines project obliquely from the tentacle, alternating with those of adjacent tentacles (Fig. 3, C). The tentacles are attached to the forepart in a ring, with a small posterior gap, just behind the
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SOUTHWARD: NEW POGONOPHORA FROM THE PACIFIC
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402 CANADIAN JOURNAL. OF ZOOLOGY. VOL. 47, 1969
flattened cephalic lobe (Fig. 4, B, C). Thefore- part is rather short, about 4 to 5 times as long as broad, and cylindrical in shape, with a ventral groove along most of its length (Fig. 4, C). In front of the bridle there are lateral, oblique ridges running forward to the sides of the cepha- lic lobe, and some specimens have a dorsal groove separating the cephalic lobe from the rest of the forepart. A pair of rounded pro- jections lie just behind the tentacle bases on the ventral side (Fig. 4, C). The bridle keels are sharp transparent crests on top of thick ridges containing black brush-like material (Fig. 4, C, D). The ridges gradually narrow towards the dorsal point of each keel. These dorsal points are widely separated, while the ventral points are fused together. In the anterior part of the trunk the two rows of metameric papillae are separated by a wide ventral furrow (Fig. 4, A, E). The well-developed ciliated band extends back on the dorsal side to between the 14th and 22nd pair of papillae (Fig. 4, A). The adhesive plaques of the anterior metameric papillae are 40-50 p across, have horseshoe-shaped black thickenings (Fig. 4, E, K), and lie on small oval cushions. Farther back the thickenings are kidney-shaped and then crescent-shaped (Fig. 4, L). The inward-pointing apodemes found in other species of Lamellisabella are scarcely noticeable in this species. There is no zone of enlarged papillae, but there is a group of smallish papillae in front of the girdles. The two girdles are each made up of about three rows of narrow platelets (Fig. 4, F, G). The platelets are 20 to 25 p long and have the anterior group of teeth smaller than the posterior group. The post- annular region bears rows of about nine papillae, with small glandular patches on the dorsal side of the body opposite them. The spermatophores are flat, with a narrow point at one end, and taper gradually into the filament at the other end (Fig. 4, M). They are about 650 p long and 180 p wide. The tube is brown and very stiff, tapering posteriorly to a flexible, whitish region. The anterior end is made up of closely overlapping segments without projecting collars, so that the surface is smooth and uni- formly brown in color.
Measurements-Tentacle crown, length 1.0 to 10.9 mm; forepart, length 1.42 to 3.7 mm, diameter 0.28 to 1.1 mm; preannular region, length 10 to 45 mm; postannular region,
length more than 100 mm in large specimens. Tube, anterior diameter 0.4 to 1.5 mm; posterior diameter, 0.35 to 0.5 mm.
Growth-The narrowest specimens, which are also the shortest, have fewer tentacles and slight- ly fewer metameric papillae than large speci- mens.
Discussion-The spine-bearing scales or plates on the tentacles of this species are unique, but other species of Lamellisabella have thick cuticle on the outer sides of their tentacles (see Ivanov 1963). In size, the new species is about the same length as L. minuta Ivanov and much shorter than L. zachsi Uschakov; its diameter, however, is greater than that of L. minuta, and near to the diameter of L. zachsi and L. johans- soni Ivanov. L. coronata is quite distinct from these three species, but has some characters in common with L. ivanovi Kirkegaard (1961), which was described from one imperfect specimen found near Panama. Because this is the only species of Lamellisabella so far described from the eastern side of the Pacific the dis- tinctions between it and L. coronata need to be carefully defined. The two species are about the same size and both have 20 or more tentacles, but L. ivanovi does not have the spiny plates so characteristic of L. coronata. A second distinc- tion lies in the bridle keels, which fuse ventrally in L. coronata but not in L. ivanovi. In addition, L. ivanovi has larger metameric plaques, 75 p across, with better developed apodemes.
Geographical Distribution and Ecology
The Pogonophora of the eastern Pacific are still very incompletely known. There are only 11 named species reported from the western continental shelf and slope of the Americas (Table 11). The Canadian collections, reported on here, should provide a fairly complete list of the species to be found on the continental slope between 1840 and 2700 m, in the region to the west of Vancouver Island and Queen Charlotte Sound. Galathealinum brachiosum probably will be discovered in this region, but was not ob- tained in these collections. Outside this rather narrow depth range some of the same species will probably be found. Polybracltfa canadensis, for example, also occurs in 220-350 m in Tasu Inlet (Queen Charlotte Islands) and may well occur over an equally wide range in other
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SOUTHWARD: NEW POGONOPHORA FROM THE PACIFIC
TABLE I1 Pogonophora of the eastern Pacific
Species Author Position Depth, m
Siboglinum veleronis S. albatrossianum S. ecuadoricum S. pusilIum Ivanov S. vancouverensis Heptabrachia ctenophora Polybrachia canadensis
Galathealinum brachiosum
G. mexicanum Lamellisabella ivanovi L. coronata Krampolinum galatheae
Hartman 1961 Cutler 1965 Cutler 1965 This paper This paper Ivanov 1962 Ivanov 1962 This paper Ivanov 1961
Adegoke 1967 Kirkegaard 1961 This paper Kirkegaard 1956 - ..
32'49' N, 11°35' W 01°03' N, 80'15' W 01°03' N, 80'15' W See Table I See Table I 43" N, 125" W 54" N, 134" W See Table I 42O4.0' N, 124'59' W 54" 23' N, 134'41' W 14'28' N, 93'09' W 05"44' N, 79"201 W See Table I 05'44' N, 79'20' W
suitable places. The present samples indicate some zonation of species with depth, Siboglinum vancouverensis being much more abundant than S. pusillum at depths of 1840 to 1900 m, while S. pusillurn is the more abundant at 2400 m and occurs without S. vancouverensis at 2675 m.
There are some affinities with the pogono- phoran fauna of the northwest Pacific; Sibo- glinum pusillum was first found south of Kam- chatka (see Ivanov 1963) and S. vancouverensis seems to be closely related to S. fedotovi, which occurs in the Bering Sea. Polybrachia canadensis is probably related to P. annulata, another characteristic Bering Sea species, which is also found in the Sea of Okhotsk. However, the remaining forms possibly belong to a group of species which is restricted to the eastern side of the Pacific; the genus Galathealinuwz for example, has not been found on the western side of the Pacific, although the pogonophoran fauna is quite well known. The comparative abundance of pogonophoran species on the western side is due to the virtual isolation of the various deep basins and trenches from one another. The shelf and slope of the American side provide
much less opportunity for the isolation of faunas and subsequent evolution of separate species, and so it is likely that the species de- scribed in this paper may be found to be quite widespread on this side of the ocean.
ADEGOKE, 0. S. 1967. Pogonophora from the north- eastern Pacific: first records from the Gulf of Tehuan- tepec, Mexico. Pacific Sci. 21: 188-192.
CUTLER, E. B. 1965. Pogonophora from the eastern tropical Pacific, including two new species of Sibo- ~linum. Pacific Sci. 19: 422-426.
HARTMAN, 0. 1961. New Pogonophora from the eastern Pacific Ocean. Pacific Sci. 15: 542-546.
IVANOV, A. V. 1960. Pogonophores. Fauna SSSR (N.S.) 75. (In Russian.)
196 1. New pogonophores from the eastern part of the Pacific Ocean. I . G~larhealinum bracl~iosum sp. n. Zool. Zh. 40: 137S-1384. {In Russian).
1962. Ncw pogonophores from the eastern part of the Pacific Ocean. 11. Hep fabracl~ia ctenoplrora sp. n. and If. raxademis sp. n. Zool. Zh. 41: 893-900. (In Russian.)
1963. Pogonophora. Academic Press, London. KIRKEGAARD, J. B. 1956. Pogonophora. First records
from the eastern Pacific. Galathea Rep. 2: 183-186. 1961. Pogonophora 111. The genus Lamellisa-
bella. Galathea Rep. 4 : 7-10. SOUTHWARD, E. C. 1969. Growth of a pogonophore: a
study of Polybrachia canadensis with a discussion of the development of taxonomic characters. J. Zool. Lond. 157. In press.
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