SARSIA

THREE NEW SPECIES OF GASTROTRICHA MACRODASYIDA FROM THE
BERGEN AREA, WESTERN NORWAY
CLAUS CLAUSEN
SARSIA
CLAUSEN, CLAUS 1996 07 01. Three new species of Gastrotricha Macrodasyida from the Bergen
area, western Norway. – Sarsia 81:119-129. Bergen. ISSN 0036-4827.
The paper describes three new macrodasyidan gastrotrichs from the Bergen area, western Norway
and is part of a series of papers with the scope of describing the Norwegian marine gastrotrich
fauna in order to extend the knowledge of Norwegian biodiversity. Paraturbanella scanica sp. n.
is described in the family Turbanellidae, and Tetranchyroderma norvegicum sp. n. and
Ptychostomella bergensis sp. n. are described in the family Thaumastodermatidae. P. scanica and
T. norvegicum were typically found in medium to coarse sand/shelly sand, while P. bergensis
inhabits shell gravel. P. scanica belongs to the species group with lateral adhesive tubes. T.
norvegicum particularly bears great resemblance to T. coeliopodium BOADEN, 1963. P. bergensis
lacks eyespots and has a paired row of ventral adhesive tubes. A tabular key to the genus
Paraturbanella is included.
Claus Clausen, Institute of Zoology, Dept. Zoological Laboratory, University of Bergen, Allégt.
41, N- 5007 Bergen, Norway.
KEYWORDS: Gastrotricha; Macrodasyida; Norwegian meiofauna; Bergen fauna; taxonomy.
INTRODUCTION
The studies of REMANE (1926, 1927) in the Kiel and Naples
regions and at Heligoland of the then little studied so-called
‘aberrant gastrotrichs’ or Macrodasyida, revealed a group
as diverse as the better known Chaetonotida. Subsequently
several workers have studied many more regions along the
European coasts. Outside Europe, investigated areas are
mostly very scattered, although several studies have been
made both in the Indian Ocean and in the
Pacific, and particularly along the Atlantic coast of North
America. The scantiness of explored regions and localities
no doubt explains that whenever new areas are studied, new
gastrotrich species, both macrodasyidans and
chaetonotidans, are quite regularly described.
d´HONDT (1971) in a synopsis of the Gastrotricha gave
a comprehensive survey of studies up to around 1970,
that includes history, geographical distribution, and a
complete reference list. HUMMON (1982) and RUPPERT
(1988) also gave a synopsis of the group, with references
that reflect various topics, systematics, microscopic
anatomy, organic systems and ecology. RENAUD-MORNANT
(1986) gave a taxonomic survey of the marine Gastrotricha
including geographic distribution.
A survey of gastrotrich studies made in the Mediterranean and in Somalia was given by HUMMON & al. (1993).
For a more complete picture of systematic studies of the
Macrodasyida, see BOADEN (1974, 1976), d´HONDT (1974),
HUMMON (1974a, b, 1977), SCHMIDT (1974), SCHOEPFERSTERRER (1974), RAO (1975, 1980a, b, 1981a, b), MAGUIRE
(1976a, b, 1977), KISIELEWSKI (1987), POTEL & REISE, 1987,
GOURBAULT & RENAUD-MORNANT (1989), HUMMON &
WARWICK (1990), CLAUSEN (1991), EVANS & HUMMON
(1991), RUPPERT (1991), EVANS (1992, 1994), JOUK & al.
(1992), EVANS & al. (1993), BALSAMO & al. (1995).
In five previous papers, seven new species of
Macrodasyida were described from the Bergen area of
Norway (see CLAUSEN 1991). In the present paper three
more new macrodasyidans are described from the west
coast of Norway: Paraturbanella scanica sp. n. in the
family Turbanellidae, and Tetranchyroderma norvegicum
sp. n. and Ptychostomella bergensis sp. n. in the family
Thaumastodermatidae.
A separate paper on Macrodasyida from the Tromsø
region of Norway is in preparation, and also a paper
treating the Norwegian marine gastrotrich fauna as a
whole. In those papers the affinities of the specific
Norwegian macrodasyidans to those of other geographic
regions will be more closely assessed.
120
Sarsia 81:119-129 – 1996
MATERIAL AND METHODS
Abbreviations used in the figures
The material was collected from subtidal sediments in
Korsfjorden, Lysefjorden, and Raunefjorden in the time span
1966-1992. Additional material was collected in the Trondheim
region in 1988 and in the Tromsø region in 1992. At depths
down to 3 m the sediment samples were collected with a finemeshed landing-net operated from a small boat; at larger depths
the sediments were either dredged or a van Veen grab or a
Petersen grab was used. The surface salinities ranged from
around 29 in Raunefjorden to 32 in the outer Korsfjorden.
Extraction of the animals from the sediment was by the
anaesthetization (MgCl2) decantation technique (see PFANNKUCHE
& THIEL 88). Specimens were observed live with Nomarski optics
using a Leitz Orthoplan microscope. Additional studies were
made on glycerol wholemounts. Drawings were based upon
photomicrographs made with Leitz Orthomat camera attached
to a Leitz Orthoplan microscope.
Whole mounts were prepared by fixing the anaesthetized animal in buffered 2.5 % glutaraldehyde and 1 % paraformaldehyde,
washing in buffer, and mounting in glycerol-ethanol; and, after
evaporation of the ethanol, sealing with Glyceel.
The set of morphological symbols and conventions used
in the text is given in Table 1.
af
Anterior foot
at
Anterior adhesive tube
bc
Buccal cavity
cg
Caudal gland
cl
Caudal lobe
co
Copulatory organ
ct
Cirrate tube
dt
Dorsal adhesive tube
eg
Epidermal gland
fl
Flagellum
in
Intestine
lao
Lateral organ (dohrni organ)
lb
Lateral bristle
lt
Lateral adhesive tube
oc
Oocyte
ov
Ovum
p
Pestle
pa
Pentancre
pd
Pedicle
pp
Pharyngeal pore
pt
Posterior adhesive tube
r
Seminal receptacle
te
Testis
vd
Vas deferens
vlt
Ventrolateral adhesive tube
vt
Ventral adhesive tube
The terminology used in the description of the reproductive
system is in accordance with RUPPERT (1991).
Sampling sites
Bergen area. 1. Ulvsundet W. 2 m, coarse shelly sand. 2. Vardøy/
Fugløy. 23 m, fine shelly sand. 3. Bondisholmen N. 7 m, medium
shelly sand. 4. Håkonsund. 1 1/2 - 3 m, medium shelly sand.
5. Horsøy N. 4 m, coarse shell sand. 6. Skotøy. 1 1/2 m, coarse
shelly sand. 7. Lauvholmen S. 3 m, coarse shelly sand. 8. Raunane.
a) N. 1 1/2 - 3 m, medium/coarse shelly sand; b) E. 3 m, medium
shell gravel. 9. Tyssøy/Kjeholmen. a) 1 m, medium sand and
shelly sand; b) 1 1/2 - 2 m, medium/coarse sand with some shelly
sand; c) 3 m, very coarse sand and shelly sand. 10. Alvøy S. 3 m,
medium sand with some shelly sand. 11. Bjorøy S. 1 m, medium
shelly sand.
Trondheim area. 12. Fjellværøy, Sandvik. 2 m, medium sand
and shelly sand. 13. Kråkvågøy, 8 m, coarse shelly sand. 14.
Tarva, Svinøya S. 4 m, medium sand with some shelly sand.
Tromsø area. 15. Brensholmen, ‘Bunker bay’. a) 1 m, medium
sand with some shelly sand; b) 2 m, coarse sand with some shelly
sand. 16. Sandvikgrunnen. 5 m, medium shelly sand and silt.
Table 1. Key to morphological symbols and conventions.
Lt
-
U
PhJIn
Columns
Rows
-
Length, total, from anterior tip of head to
posterior tip of caudum or pedicles excluding
adhesive tubes
Percentage units of Lt from anterior to posterior
Junction between pharynx and intestine
Longitudinal in orientation
Transverse in orientation
THE SPECIES
Family Turbanellidae REMANE, 1925
Genus Paraturbanella REMANE, 1927
Paraturbanella scanica sp. n.
(Figs 1, 2)
Diagnosis
A Paraturbanella with an adult length to at least 950 µm;
PhJIn at U 25-30. Without an outer marked head. With
lateral and dorsal adhesive tubes; dohrni tubes small.
Pestles present. Head portion with a pair of flagella.
Buccal cavity moderately cuticularized. A small median
cone between caudal lobes; caudal lobes with one row of
adhesive tubes; distance between tips of lobes less than
width of trunk. Locomotor cilia as paired lateral tracts to
anus, thereafter a continuous field.
L o c a l i t i e s . Bergen area. Stn 1. May 1979. Stn 3. Apr
1978. Stn 4. Aug 1965, Apr 1978, Apr 1980. Stn 5. Mar
1979. Stn 8. a) Aug, Sept, Oct, Dec 1979; b) Nov 1989. Stn
9. b) June 1989; c) May 1989.
Trondheim area. Stn 12. June 1988, Stn 14. June 1988.
Tromsø area. Stn 15. a) June 1992; b) June 1992. Stn 16.
June 1992.
Clausen– Three new species of Gastrotricha Macrodasyida from western Norway
121
M a t e r i a l e x a m i n e d . About 35 specimens.
H o l o t y p e . Adult specimen 800 µm long, glycerol
preparation, collected by the author on 7 June 1989. Type locality.
Norway, Raunefjorden, Tyssøy/Kjeholmen, 60° 17.7’ N, 5° 9.2’
E, bottom coarse sand and shelly sand, depth 2 m. Zoological
Museum, University of Bergen (ZMBN), Cat. No. 66759.
P a r a t y p e s . Two specimens, wholemounts, from the type
locality. ZMBN, Cat. Nos 66760-61.
E t y m o l o g y. The name is derived from the name Scandinavia.
Description
Length of adults 650-950 µm; largest width 60-75 µm at U
45-60; PhJIn at U 25-30 (mean 27). Body elongate with
smooth lines, head tapered, with no neck constriction; a
small cone (ca 3 x 5 µm) between tapered caudal lobes;
mean widths of head/trunk/base of caudal lobes: 55/62/36
µm at U 20/55/95-97 respectively; distance between tips
of spread caudal lobes less than width of trunk; indistinct,
flat pestle organs at the level of hind end of buccal cavity.
Mouth rim with 4 µm long fine bristles; lateral to mouth
three pairs of 17-20 µm long, thick ‘bristles’ (compound
cilia), occasionally making quick vibrations or rapid strokes;
three ventrolateral tufts of cilia in anterior head region, and
one dorsal pair on level with hind end of buccal cavity; at
U8 laterally a paired flagellum (ca 30 µm); sensory hairs
(20-27 µm) in paired lateral and dorsolateral columns along
trunk. Glands of band-like secretion type dorsolaterally in
irregular paired columns, most numerous posteriorly;
diameter up to 10 µm, shape retort-like.
Ventral ciliation: locomotor cilia mainly in a paired band
from anterior border to anus (scant ciliation also medially),
thereafter complete ciliation to base of caudal lobes;
motion a slow glidening.
Adhesive tubes: present in anterior, lateral, dorsal and
posterior series, along with the dohrni tubes, distinctive of
the genus. Anterior tubes on a common base at U 11, six to
nine per side, length 6-12 µm, increasing in medial
direction; well separated from these (at U 14) the dohrni
tubes, implanted ventrolaterally and directed obliquely backwards; cuticular base of organ slender (10 x 4 µm), longer
tube (16-24 µm, tip usually visible from above), shorter
(ventral) tube (7-10 µm), directly beneath. Tubes of lateral
columns implanted slightly ventrolaterally, six to nine per
side, 12-17 µm long, extending from shortly
behind pharynx to U 75-80. Dorsal tubes, four to five per
side with similar distribution; in both series a decrease in
separation of tubes caudad. Posterior tubes, 8-13 (mostly
10-11) pairs (6-14 µm) in one row on posterior margin of
caudal lobes; tubes usually alternating in length, overall lengths
increasing in lateral direction.
Fig. 1. Paraturbanella scanica sp. n. General organization
(anterior feet and lateral organs drawn as if lying dorsally).
Scale line, 100 µm.
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Sarsia 81:119-129 – 1996
Fig. 2. Paraturbanella scanica sp. n. LM graphs. A. Habitus. B. From middle body region, ventral view, showing testes and
recurved vasa deferentia. C. Posterior part of animal, frontal optical section, showing copulatory organ. D. Posterior part
of animal, sagittal optical section, showing copulatory organ. Scale lines in A, 100 µm, in B, C, and D, 50 µm.
Clausen– Three new species of Gastrotricha Macrodasyida from western Norway
Digestive system: buccal cavity spacious (length 2530 µm, width 12-16 µm), moderately cuticularized; pharyngeal knobs prominent, close to intestine; intestine of
even width in its first half, then gradually tapering to the
subterminal, ventral anus (U 95); diatoms sometimes
present in intestine.
Reproductive system: paired testes from U 40, far
behind pharynx, continuing as vasa deferentia to U 60
before turning medioanteriorly to unite subintestinally
at U 45; sperm filiform, with five open windings in the 15
µm long head portion. Paired ovaries posterior to vasa
deferentia; large oocytes dorsolaterally at U 50-65 in
specimens from about 650 µm length. Copulatory organ
seen only in two specimens, at U 85-95; shape in frontal
section like an eight, in side view like a heart.
1976, and, P. aggregotubulata EVANS, 1992. Like P. scanica,
P. aggregotubulata and P. armoricana have dorsal tubes;
differences are, lack of pestles and median cone, noncuticularized buccal cavity, and larger caudal lobes in P.
armoricana, which also is smaller and appears to move
faster (SWEDMARK 1954), probably because of its entire
ventral ciliation; P. aggregotubulata differs in being
smaller, has a head incisure, has a larger number of dorsal
and a smaller number of posterior adhesive tubes, and,
the columns of lateral tubes initiate in pharyngeal region;
further it lacks pestles, and has testes reaching far longer
in front, as do also the vasa deferentia; an especially clear
difference regards the anterior tubes: while their lengths
increase in medial direction in P. scanica, the shortest
tube of P. aggregotubulata is the medial one, and the
longest tube the next lateralmost one.
P. intermedia resembles P. scanica in having indistinct
pestles and a median cone; differences are, besides the lack
of dorsal tubes in P. intermedia, presence of a distal seta on
some of the lateral tubes, a heavier cuticularization of buccal
cavity, higher number of anterior tubes, a broader base and
longer tubes in the dohrni organ, besides that it is smaller
Taxonomic affinities
P. scanica joins a group of four species with lateral adhesive tubes (see also Table 2): P. armoricana (SWEDMARK,
1954), P. intermedia WIESER, 1957, P. eireanna MAGUIRE
Table 2. Tabular key to species of Paraturbanella. I-VIII = Morphological characters
used for taxonomical discrimination.
I II III IV V VI VII VIII
p p c p l p s b
p p c p i o s b
p p o o l o s b
p o c p l p s b
p o c o l o s b
o o o p l o s b
o o c p l p s b
o o c p i p w b
o o c p i o w b
o o c p h o w b
o o c p h o s b
o o c p h p s b
o o c p l p s 1
o o c p l p s 2
NO.
1
2
3
4
5
6
7
8
9
10*
11*
12*
13
14
SPECIES
scanica sp. n.
aggregotubulata EVANS, 1992
armoricana (SWEDMARK, 1954)
intermedia WIESER,1957
eireanna MAGUIRE, 1976
cuanensis MAGUIRE, 1976
dohrni REMANE, 1927
pallida pallida LUPORINI &al., 1971
pallida pacifica SCHMIDT, 1974
teissieri SWEDMARK, 1954
microptera WILKE, 1954
mesoptera RAO, 1970
boadeni RAO & GANAPATI, 1968
palpibara RAO & GANAPATI, 1968
* = probably conspecific (see KISIELEWSKI 1987)
I
- Lateral adhesive tubes:
p = present
o = absent
II - Dorsal adhesive tubes:
p = present
o = absent
III - Wall of buccal cavity:
c = cuticularized
o = not cuticularized
IV - Median cone between caudal lobes:
p = present
o = absent
123
V
- Anterior body region:
h = forming a head around the buccal cavity
i = lateral incisions at level of dohrni tubes
l = in line with the rest of the body
VI - Pestle organs:
p = present
o = absent
VII - Body outlines:
s = smooth
w = with wave-like undulations
VIII - Anterior adhesive tubes:
b = base lobe-shaped
1 = base rod-shaped, one row of tubes
2 = base rod-shaped, two rows of tubes
124
Sarsia 81:119-129 – 1996
than P. scanica, with a higher ratio pharynx/body length.
MAGUIRE (1976b) described in P. eireanna a long, flexible
hair on each side of the head similar to that of
P. scanica. Besides lack of dorsal tubes, P. eireanna has a
relatively longer ventral dohrni tube, different arrangement
of posterior tubes, absence of a median cone, and smaller
size; neither do pharyngeal walls extend up around the
buccal cavity, which shows great variability of cuticular
plates; finally, epidermal glands are restricted to posterior
body region.
The forward turn and communication of the vasa
deferentia were not noticed until the description of
P. aggregotubulata (see EVANS 1992), except that MAGUIRE
(1976b) reported ‘a transverse sperm bundle’ in
P. cuanensis. As the statement of RUPPERT (1988) that
Paraturbanella has straight vasa deferentia with separate
pores is not verified in the present study either, it seems
that Paraturbanella is similar to the other genera of the
family in this respect.
Family Thaumastodermatidae REMANE, 1926
Subfamily Thaumastodermatinae RUPPERT, 1978
Genus Tetranchyroderma REMANE, 1926
Tetranchyroderma norvegicum sp. n.
(Figs 3, 4)
Diagnosis
A Tetranchyroderma with an adult length to at least 380
µm; PhJIn at U 35-42; body shape semi-rectangular with
a short, bilobed caudum. Glands numerous, unevenly
spaced along length of body. Cuticular armature of large
pentancres. Three pairs of dorsolateral tubes of ‘cirrata’
type. Adhesive tubes: anterior, seven to eight per side in
a caudally opening arc; about 16 ventrolateral tubes, one
small near anterior group, the others long, in anterior and
middle intestinal region; four to eight pairs of ventral
tubes at U 85; up to 30 posterior tubes, along posterior
and lateral trunk borders; pedicles with three tubes (one
cirrate). Reproductive system: gonads agree with genus
pattern; sperm filiform, ovum above middle portion of
intestine; copulatory organ broadly pear-shaped.
L o c a l i t i e s . Bergen area. Stn 2. Sept 1992, Feb 1993.
Stn 6. Nov 1965. Stn 7. Dec 1966. Stn 9 a) Mar 1990; b)
Feb, May 1989, Apr 1992.
Trondheim area. Stn 13. June 1988.
M a t e r i a l e x a m i n e d . Live studies of about 30 specimens.
H o l o t y p e . Adult specimen 300 µm long, glycerol preparation,
collected by the author on 22 Feb. 1993. Type locality. Norway,
Korsfjorden, Vardøy/Fugløy, 60° 10,1' N, 5° 0,6' E, bottom medium shelly sand, depth 20 m. ZMBN, Cat. No. 66762.
P a r a t y p e s . Three specimens, wholemounts, from
Tyssøy/Kjeholmen. ZMBN, Cat. Nos 66763-5.
E t y m o l o g y. The species name is the Latin adjectival form of
the name Norway.
Description
Adult specimens ca 250-380 µm; PhJIn at U 35-42. Body
semi-rectangular with somewhat inflated trunk narrowing
quickly to a short, bilobed caudum (pedicles); posterior
border slightly incurved; widths of head/at neck/trunk/
caudal base 40-60/40-55/50-70/22-28 µm at U 8/U 15/U
60/U 97 respectively. Sensory hairs (ca 6 µm) as a fringe
around oral opening ; five bristles (18 µm) with prominent
basal cone (3 µm) behind dorsal mouth rim just in front of
anterior row of cuticular hooks, two further ones (16-17
µm) and one flagellum (ca 22 µm) lateral to mouth; other
sensory hairs (ca 17 µm ) in paired lateral and dorsolateral
columns, some 20 µm apart in the lateral column, more
spaced in the other column. Locomotor cilia (ca 15 µm) a
continuous field. Eight to ten pairs of glands of granular
type (up to 18 µm diameter) from middle pharyngeal region to near caudum (U 25-95), first pair dorsal, the remainder dorsolateral; about the same number of smaller
glands of homogeneous type both dorsolaterally and laterally, distributed all along the body from behind oral hood.
Dorsolaterally three pairs of tubes of ‘cirrata’ type,
more or less filled with small granules, at about U 20 (ca 13
µm, range 11-16), U 45 (ca 16 µm, range 14-18), and U 70
(ca 15 µm, range 14-17).
Cuticular armature: hooks of pentancre type, in about
15 columns and 70 rows; all tines of same length; individual hooks of variable lenghts along the length of body:
in mid-dorsal column 2-3 µm nearest to dorsal mouth rim,
6-7 µm in anterior, as compared with only 5 µm in posterior, pharyngeal region; length then gradually increasing to
7-8 µm (width between opposite prongs 5-6 µm) along
posterior half of trunk, and abruptly decreasing to ca 2 µm
on pedicles.
Adhesive tubes: anterior, seven to eight (in one case nine
on one side) pairs, one medial (5 µm) at U 10, the others
ventrolateral (8-10 µm) at U 9-13; ventrolateral, up to
16 per side, a small one (ca 9 µm) at U 15, the remainder
larger (12-30 µm), typical lengths 16-24 µm, evenly spaced
from about U 40 to U 80; at U 85 a paired group of four to
eight ventral tubes arranged in an anteriorly opening arc;
tubes in the midst of arc longest, with gradual decrease of
tube length towards either side; mean lengths of tubes (six
measures): longest tube 17 µm (range 14-20), medialmost
Clausen– Three new species of Gastrotricha Macrodasyida from western Norway
125
Fig. 3. Tetranchyroderma norvegicum sp. n. A. General organization, dorsal view. B. Ventral view of
another specimen, showing adhesive tubes, cirri, and pentancres (drawn only on one side). Scale line, 50 µm.
one 11 µm (range 8-15), lateralmost one 9 µm (range
6-14); posterior tubes, up to 15 pairs along posterior and
lateral trunk borders from U 90 backwards; pedicles with
three tubes, one dorsally implanted of ‘cirrata’ type
(14 µm) and two horizontal (10 µm); between pedicles
six to eight tubes (6-8 µm), and lateral to pedicles on each
side six to eight tubes, one large (ca 18 µm, range 15-20)
at posterior trunk corner, the others 10-12 µm.
126
Sarsia 81:119-129 – 1996
Fig. 4. Tetranchyroderma norvegicum sp. n. Habitus of
adult. Nomarski optics. Scale line, 50 µm.
Digestive system: mouth widely extendable; pharynx
narrowing gradually over most of its length towards junction with intestine at U 38-44; intestine widest in its
middle portion.
Reproductive system: gonads in agreement with the
genus pattern; anterior end of testis may reach to end of
pharynx; sperm filiform, ca 95 µm long, of which tail
60 µm, last three fourth of head and middle piece with
tight spiral coils; ovum (ca 70 x 40 µm, nucleolus round,
15 µm) mid-dorsally above third fifth of intestine; copulatory organ bulbously pear-shaped (28 x 20 µm in horizontal projection), with a longitudinal channel opening at
U 90; seminal receptacle rounded (ca 15 x 18 µm).
Taxonomic affinities
Of the around 17 described Tetranchyroderma species
with pentancres, only four have ventral ‘feet’: T.
antennatum LUPORINI & al.,1970 (one tube), T. coeliopodium
BOADEN, 1963 (five to six), T. pacificum SCHMIDT, 1974
(four to seven), and T. thysanophorum HUMMON & al.,
1993 (one tube). T. antennatum differs from all the others
in having tentacles and large, fleshy pedicles, T. pacificum
differs in having very slender ventral tubes inserted on a
protruding base, and T. thysanophorum in bearing trailing
filaments in posterior part of trunk. T. coeliopodium and
T. norvegicum stand out from all the others in having ventral feet with several tubes inserted directly on the trunk.
Although agreeing in several aspects, e. g. shape of
pentancres and disposition of adhesive tubes, there also
are several, albeit often minor, dissimilarities between the
two species: T. coeliopodium (1) is smaller (maximum
280 µm versus 380 µm), (2) has a rounded posterior end v.
broad indention, (3) has about half the number of both
anterior and posterior adhesive tubes as does
T. norvegicum, (4) has short (6.5 µm or slightly more) v.
long (mostly 20 µm or more) ventrolateral tubes, (5) has
ventral feet of uniform, relatively short tubes (8-9 µm,
lateralmost tube longest) arranged in a transverse row versus tubes of mixed lengths (6-20 µm, middle tubes longest) arranged in an arc, (6) apparently lacks cirrate tubes
and (7) frontal bristles, and (8) has spermatozoa of 150
µm length (head 25 µm ) versus 95 µm (head 35 µm). As
both size and disposition of the tubes in the more dorsal
column are much the same in the two species, it could be
that BOADEN (1963) failed to recognize their cirrate nature;
but even so, it seems proper to regard T. coeliopodium and
T. norvegicum as separate, even if closely related, species.
KISIELEWSKI (1987), who reported T. coeliopodium from
Roscoff and made a comparison of different characters in
the French and the British populations, did neither note a
cirrate appearance of the tubes in question.
Genus Ptychostomella REMANE, 1926
Ptychostomella bergensis sp. n.
(Figs 5, 6)
Diagnosis
A Ptychostomella with an adult length to at least 360 µm;
PhJIn at about U 34; mouth very extensible, trunk moderately inflated, caudum bilobed; eyespots lacking; glands of
three types; cuticular armature absent. Adhesive tubes:
anterior, seven pairs, a group of three in an arc near mouth,
and a second group of four in a column or oblique row
ventrolaterally; nine ventrolateral pairs, a small one anteriorly
and eight in intestinal region; two pairs of lateral tubes, in
mid- and posterior body region; four pairs of ventral tubes;
posterior tubes up to 16 per side, two at lobe tip, up to five
flanking the lobe medially, and up to nine laterally.
Reproductive system: gonads agree with genus pattern;
sperm filiform; ovum large, above middle portion of intestine;
copulatory organ large, pear-shaped.
L o c a l i t y. Stn 8b. Oct, Dec 1966, Nov 1989, Feb 1990, Aug
1991, Mar 1992.
Clausen– Three new species of Gastrotricha Macrodasyida from western Norway
127
M a t e r i a l e x a m i n e d . Live studies of eight specimens.
H o l o t y p e . Adult specimen 320 µm long, glycerol preparation,
collected by the author on 20 Mar 1992. Type locality. Norway,
Raunefjorden, Raunane, 60° 15,8' N, 5° 10,8' E, bottom medium
shell gravel, depth 3 m. ZMBN, Cat. No. 66776.
P a r a t y p e . Adult specimen, glycerol preparation, from
the type locality. ZMBN, Cat. No. 66777.
E t y m o l o g y . The species name is the Latin adjectival
form of the name Bergen.
Description
Body length up to at least 360 µm; pharyngeo-intestinal
junction at about U 36. Body with smooth lines, narrowing gradually to a well developed bilobed caudum; widths
of head/at neck/trunk/caudal base: 45-70/45-50/60-70/3035 µm at about U 7/15/55/96 respectively; a fringe of
sensory hairs around oral opening (7-9 µm dorsally, about
4 µm ventrally), sparse sensory hairs on oral hood with
one longer (ca 30 µm) pair at U 5; other sensory hairs
(14-17 µm) in two lateral columns along trunk sides (ca
10 per column). Glands of three types, about 13 pairs of
round, course-granulated glands (to 14 µm diameter)
laterally (an unpaired one near posterior trunk margin),
about the same number of more irregularly distributed
pairs of fine-granulated glands (to 10 µm) more dorsally,
and, scattered dorsolaterally, smaller, oblongue to round
glands with homogeneous, lightrefringent contents.
Adhesive tubes: anterior tubes, seven pairs, in two
groups: three tubes (8-12 µm) evenly distributed near ventral mouth rim, medialmost one shortest; four tubes
(7-11 µm) shortly behind, inserted close together in a
ventrolateral column, anteriormost tube longest (with
widely opened mouth, second group appearing almost as
a transverse row); lateral tubes, two (ca 15 µm) pairs at
U 55 and U 92, first pair inserted slightly ventrolaterally;
ventrolateral tubes, nine pairs, a small one (11 µm) at
U 19, and eight tubes (14-16 µm) between U 40 and U 75,
ventrolateral to ventral in position; ventral tubes, four pairs
(9-12 µm) in an oblique row from U 77 to U 80, medial(posteriormost) tube shortest; posterior tubes, up to 16
per side, two (ca 10 µm) at tip of lobe, three to five (ca 8
µm) flanking the lobe on medial side, and seven to nine
ventrolaterally inserted ones (ca 8 µm) on lateral side,
column of tubes reaching anteriorly at level with or in
front of posteriormost lateral tube.
Digestive system: oral opening up to 70 µm in width
(45 µm when at rest), oral hood extending forward above
mouth from U 00 to U 10; pharynx narrowing to a constant width of about 25 µm in its posterior half; intestine
about 30 µm broad before narrowing in its posterior half
toward anus.
Fig. 5. Ptychostomella bergensis sp. n. A. General organization,
ventral view. Dorsal glands stippled. Scale line, 50 µm.
Reproductive system: testis from near posterior end of
pharynx; sperm filiform, about 130 µm long with a 17 µm
long loosely spiralized anterior portion, followed by a
26 µm long tightly spiralized head portion. One ovum,
suboval (maximum diameter about 55 µm), dorsally in
mid-intestinal region. Copulatory organ large, pear-shaped
(33 x 24 µm) at U 80-90; seminal receptacle (about 25 x 20
µm) at anterior end of caudal organ, containing sperm.
A pair of caudal glands present close to posterior part of
copulatory organ.
128
Sarsia 81:119-129 – 1996
species in lacking the posterior lobes, and P. tyrrhenica
differs with respect to the construction of the accessory
genital organs. Of the two remaining species, P. bergensis
is closest to P. ommatophora regarding general body
shape, but lack of eye spots and differences with respect
to the adhesive tubes separate it from this species; thus
P. ommatophora has four instead of two lateral tubes, a
higher number of ventrolateral tubes, and lacks ventral
tubes. P. pectinata has at best indistinct posterior lobes
(see REMANE 1926, fig. 54), and the clustered small lateral
adhesive tubes accompanying the large lateral tube in
mid-body region also disagree with P. bergensis. A ventral insertion of the tubes of the ventrolateral column,
like the condition in P. bergensis , was also reported in P.
tyrrhenica (HUMMON & al. 1993). A special, paired group
of ventral adhesive tubes like those found in P. bergensis
was not reported in any of the other species of the genus.
Associated fauna (Stn 8b)
Fig. 6. Ptychostomella bergensis sp. n. Habitus of
adult. Nomarski optics. Scale line, 50 µm.
Cnidaria (Halammohydra intermedia CLAUSEN, 1967).
Gastrotricha (Macrodasys buddenbrocki REMANE, 1924,
M. cephalatus R EMANE , 1927, M. sp., Mesodasys
laticaudatus REMANE, 1951, Lepidodasys martini REMANE,
1926, Crasiella diplura CLAUSEN, 1968, Diplodasys cf.
ankeli WILKE, 1954, Thaumastoderma bifurcatum CLAUSEN,
1991, Th. heideri REMANE, 1926, Paraturbanella scanica
sp. n.) Polychaeta (Microphthalmus ephippiophorus
CLAUSEN, 1986, Ophryotrocha sp., Nerilla antennata
SCHMIDT, 1848, Nerillidium gracile REMANE, 1925,
Protodrilus sp., Diurodrilus sp., Trilobodrilus heideri
REMANE, 1925). Gastropoda (Embletonia pulchra ALDER
& HANCOCK, 1851). Echinodermata (Leptosynapta minuta
BECHER, 1906).
Remarks
ACKNOWLEDGEMENTS
A pair of low pestles were apparently observed lateral to
the mouth in one specimen (the presence of such organs
may be obscured by the pectinate sculpturing of the oral
margin). Prominent pestles are present in P. mediterranea
(REMANE 1927), and HUMMON & al. (1993 fig. 9) pictured
pestles or bulbous tentacle-like formations in P. tyrrhenica
I thank the Institute of Fishery and Marine Biology,
University of Bergen for supply of material, Kjell Toklum
for field assistance, and Dr Glenn Bristow for controlling
the English. I also thank The Institute of Zoology,
University of Bergen for working facilities. The work has
been supported by The Norwegian Council for Research.
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Accepted 6 February 1996.