#Synonchium capense$ n. sp. provenant de dunes sableuses des côtes d'Afrique du Sud est décrit. Il diffère de l'espèce type, #S. obtusum$ Cobb, 1920, par la présence de trois dents de même taille à l'apex de chaque mandibule et par l'absence de ponctuations sur la cuticule. La nouvelle espèce est également comparée à #S. depressum$ Gerlach, 1954 et #S. pacificum$ Yeates, 1967, et une clé d'identification est proposée pour les quatre espèces connues. La morphologie des papilles labiales et céphaliques et l'anatomie de la gonade mâle chez les espèces du genre sont discutées. Un important organe glandulaire associé au système reproducteur femelle est décrit chez #S. capense$ n. sp. (Résumé d'auteur

Heyns, J.

Swart, A.

Horizon / Pleins textes

Fundam. appl. Nematol., 1995, 18 (6), 523-529
Synonchium capense n. Sp.
from South Mrica (Nematoda : Cyatholaimidae)
Juan HEYNS* and Antoinette SWART**
* Department of Zoology, Rand Afrikaans University, P. O. Box 524, Auckland Park 2006, South Africa and
** Biosysternatics Division, Plant Protection Research Institute, Private Bag X134, Pretoria 0001, South Africa.
Accepted for publication 10 October 1994.
Summary - Synonchium capense n. sp. is described from dune sands along the South African coast. It differs from S. obtusum Cobb,
1920, the type species, in having oruy three similar-sized teeth at the apex of each mandible, and in the absence of puncrations on the
cuticle. Ir is also compared with S. depressum Gerlach, 1954 and S. pacificum Yeares, 1967, and an identification key is provided for
the four known species. The morphology of labial and cephalic papillae and male gonads in Synonchium spp. are discussed, and a
large glandular organ associared with the female reproductive sysrem is described in S. capense n. sp.
Résumé - Synonchium capense n. sp. provenant d'Afrique du Sud (Nematoda : Cyatholairnidae). - Synonchium capense
n. sp. provenanr de dunes sableuses des côres d'Afrique du Sud esr décrit. TI diffère de l'espèce type, S. oblusum Cobb, 1920, par la
présence de trois dents de même raille à l'apex de chaque mandibule et par j'absence de poncruations sur la cuticule. La nouvelle
espèce est également comparée à S. depressum Gerlach, 1954 et S. pacificum Yeares, 1967, er une clé d'identification esr proposée
pour les quatre espèces cormues. La morphologie des papilles labiales et céphaliques er l'anaromie de la gonade mâle chez les espèces
du genre sonr discutées. Un importanr organe glandulaire associé au système reproducteur femelle est décrir chez S. capense n. sp.
Key-words : Nemarodes, Cyatholaimidae, Synonchium.
Only three nominal species are known in the genus
Synonchium Cobb, 1920 viz. the type S. obtusum Cobb,
1920, S. depressum Gerlach, 1954 and S. pacificum
Yeates, 1967. Information on these species is rather lim-
ited. S. depressum and S. pacificum have barely been
mentioned in the literature since their original descrip-
tion, while S. obtusum has been recorded by Chitwood
(1960) and on nwnerous occasions by Gerlach (1952,
1964, 1967), who recorded specimens from severallo-
calities, with short descriptions. The ctiscovery of a Syn-
onchium species in dune sands in four places along the
South African coast offered the opportunity to srudy the
morphology of a member of this genus in greater detail.
Standard extraction and fixation techniques were
used and nematodes processed into anhydrous glycerine
according to Thorne's slow method. Preparation for
SEM was done as described by Swart and Heyns
(1987).
Synonchiurn capense s. sp.
(Figs. 1, 2, 3)
MEASUREMENTS
See Table 1.
DESCRlPTION
Adult : Body stout, cylindrical, mostly straight to near-
Iy straight when relaxed by heat. Lip region rather trun-
cate, not offset, but slightly narrower than adjoining
ISSN 1164-5571195/06 $4.00/© Gaulhier-Villars- ORSTOM
neck. Mouth opening surrounded by twelve lobes,
which constirute the anterior ends of twelve sc1erotized
skeletal elements. Outside these lie six petal-shaped lips,
each bearing a large inner labial papilla. The six outer
labial papillae are somewhat smaller, and the laterodor-
saIs and lateroventrals are c10sely approximated, on their
lateral sides, by the four even smaUer cephalic papiUae.
Numerous lateral pores, with the anteriormost ones in
most specimens siruated before the amphids; rather ir-
regularly distributed, especially anteriorly and posterior-
Iy, and in two irregular rows along the lateral chord over
the rest of the body. Distinct transverse striae. Annules
1.6 to 2 f.Lm wide, bearing indistinct linear markings.
Amphids with one and one half spirals, somewhat oval-
shaped , wider than high. Stoma in two sections, the
anterior wider part with sc1erotized elements which ap-
pear in latera] view as e twelve) rib-like structures,
which can hinge outward when the stoma is everted.
Second part of stoma with three mandibles, each bear-
ing three similar-sized teeth at the ctista] end. Posterior
part of stoma surrounded by anterior swollen part of
cylindroid pharynx. Lwnen of pharynx triradial in cross
section and interrupted in four places by breaks in the
pharyngeal tissue, which may indicate the location of
pharyngeal glands. Nerve ring surrounding pharynx
near its midclle. Carctia with a ctistinct boat-shaped
valve, and surrounded by three flattened ceUs. Intestine
a prominent feature, only three ceUs in circumference
523
J. Heyns & A. Swarl
Table 1. Morphomelric daza of Synonchium capense n. sp. from four localilies on lhe Soulh African coast. (ail measurements in fLm,
except L).
Locality Algoa Bay Sedgefield Cape Strandfontein
Agulhas
Specimens Holotype Paratype Paratype Female Male Male Female Male
female females males
n 1 10 9 3 2 1 1 3
L (mm) 1.62 1.53 1.44 1.49-1.69 1.13-1.21 1.47 1.44 1.35-1.48
(1.42-1.64) (1.32-1.61)
a 27.0 27.3 28.5 21.3-30.2 21.0-27.9 24.5 24.0 22.6-25.0
(22.6-31.9) (26.4-30.7)
b 8.4 8.3 8.9 8.4-8.9 7.5-7.9 9.2 8.3 7.4-8.2
(7.6-9.0) (8.5-10.1)
c 50.6 50.7 55.5 54.8-57.3 49.1-50.4 58.8 53.3 51.9-54.8
(44.2-53.3) (48.5-63.6)
c' 0.84 0.76 0.68 0.58-0.74 0.57-0.68 0.64 0.69 0.61-068
(0.67-0.86) (0.55-0.81)
V 61.4 61.9 61.5-63.6 60.4
(59.9-63.3)
Stoma length 38 37.2 31.9 34-39 29-30 30 32 25-30
(34-38) (29-34)
Mandible length 21 20.6 18.0 19-21 18-19 17 18 16-17
(19-21) (17-19)
Amphid : ta front
end 15 14.5 12.3 13-16 10-13 14 13 12.5-13
(12.5-15) (10-15)
height 9 8.5-10 7.5-9 8-10 8-8.5 8 9 8-9
(n =6) (n =8)
width Il 10.5-12 10-11.5 10.5-11.5 12 12 12 12
(n =6) (n =8)
% cbd* 24 25.2 28.5 23-25.3 29-31.6 29 28 24-30
(21-29) (26-32)
Taillength 32 30.1 25.7 26-29.5 23-24 25 27 25-27
(28-32) (22-30)
Spicule length :
left 49.7 50-53 45 50-56
(41-64)
right 53.9 53 56 51-57
(42-64)
Supplement 1 ta
anus 13.5-17.5 17 16 17-19
(n =7)
Supplement 2 ta
anus 22-26.5 25-28 25 27-28
(n =5)
* cbd =corresponding body diamerer.
524 Fundam. appl. NemalOl.
Synonchium capense n. sp.
o
o
.
o
__3_0--,-p_m _~ C - F
_--,3=--O,-,,,=--m__~. G 1M
__'-e:3--,p_m A,B
A
o
•,
o
o
JI/.
Fig. 1. Synonchium capense n. sp. A, B: Female and male, enâre body; C: Pharyngeal region, sllblaceral viewj D : Head, median view
showing mlisClilatllre; E: Head, median view showing mandibles and rib-like slomalal skeletal slruclllreSj F: Head, laleral, SlIrface viewj
G-M : Seclions al level of: inner labial papillaej sLOmalal skeletal slruclllres as well as ollter labial and cephalic papillae, mandibular leelh,
mandibles, pharynx, cardia, and intesline, respeclively.
Vol. 18,no 6-1995 525
J. Heyns & A. Swarl
c
__3=-O=-..::p_m_~ A - D, J. K
~_7_0-,-p_m__ E - 1
Fig. 2. Synonchium capense n. sp. A : Female lail in Lateral view; B : Female lail in ventral view, showing internal slruClures plus anus
and body pores; C: Ventral view oflail offemale specimenfrom Sedgefield showing a dislinCI spinnerel (lwte secretion; also shown is lhe anus
and narrow ventral chordflanked by somatic muscles); D: Aiale lail; E: Female reproductive system, ventral view (note large glandular
struclures on either side of vulva, and prominent lateral glands); F: Ventral view of posterior reproduClive branch of anolher female; G:
POSteriM reproduclive lYranch, sublateral view; H: Reproduclive syslem of a young fernale; 1: Poslerior reproductive branch of anolher
specimen; J: Ventral view of vulval region, surface view; K: Somatic muscles going round vulva/vagina.
526 Fundam. appl. NemaLOl.
Synonchium capense n. sp.
Fig. 3. Synonchium capense n. sp. A : Female head in dorsolateml view, sLOma in normal, relra<:led position; B : Female head infTonlal
view, SLOma partially everted; C: Female head in laierai view, sLOma partially everted; D : Male h.ead in frontal view, sLOma parlially
everled; E: Frontal Vlew ofhead, showing leelh; F: Female tail (ilp = inner labial papilla; olp = ouler labial papi/la; cp = cephalic papilla;
aa = amphid apeTlltTe; b· = anten'or end of skeletal elemenl). (Bar equals 10 !-Lm).
Vol. 18, n° 6 - 1995 527
J. Heyns & A. Swan
and the lumen with irregular and variable appearance.
Intestine with two distinct ceU types, one type with nu-
merous smaU granules, the other (? secretory) ceUs,
which are more numerous in the ventricular area, with
larger globules and prominent nuclei. Rectum shorter
than anal body diameter, without special features. Anus
a crescent-shaped, transverse opening. Tail bluntly co-
noid. Development of spinneret highly variable, appar-
ently absent in most specimens, rudimentary in others,
but fairly well-developed in occasional specimens.
Female : Didelphic, with opposed, reflexed ovaries.
Vulva a small 12-14 J..lm long transverse slit. Vagina
short and not very muscular. Uterus broad, not dis-
tinctly separated from oviduct, the latter with a dark,
optically dense yellowish area. On each side of the vagi-
na, and Iying bet\veen the uterus and the body waU, on
the ventral side, there is a flattened, multicellular struc-
ture, its 26 to 28 ceUs forrning a solid, one-Iayered rect-
angular mass. This structure, which is probably of glan-
dular nature, is already well-developed in young females
with a weakly developed reproductive system.
Male: General morphology similar to female. Two
opposed, outstretched testes, the anterior one better de-
veloped than the posterior. Spicules slightly ventraUy
curved, siender, proximally weakly cephalated, distally
rather sharply bent ventrad. In many specimens the
righthand spicule is somewhat longer than the lefthand
one. Gubernaculum absent. There are usually two,
sometimes only one, inconspicuous ventromedian prea-
nal supplements; when only one visible, it is always the
posteriormost one. Supplements very difficult to ob-
serve when not in a perfectly lateral view. Sperm ceUs in
situ in male are ovoid to nearly round, and vary in size
from 6-10 x 8-12 J..lm. When observed in the uteri of
impregnated females, sperm cells appear more roundish
and measure 5-8 x 5-9 J..lm.
DlAGNOSIS AND RELATIONSHIPS
Synonchium capense n. sp. is characterized by three
similar-sized teeth on the mandibles, absence of distinct
punctations on the cuticle, bluntly rounded tail, t\vo
(rarely one) ventromedian supplements in male, and
absence of gubernaculum.
S. capense n. sp. differs from the type species S. ob-
lusumy as described by Cobb (1920) and Chitwood
(1960), in the following : only three teeth on each man-
dible, absence of circular punctations on the cuticle,
undifferentiated lateral field, smaller lateral organs and
smaller body pores. It corresponds with S. depressum in
having three similar-sized teeth on each mandible, but
differs in tail shape (bluntly rounded vs conoid), shape
of amphid (almost circular vs three times as wide as
high), ornamentation on cuticle (longitudinal markings
vs circular punctations) and length of spicules (41-64 vs
78 J..lm). The new species differs from S. paci/icum in
having only three teeth on each mandible vs five, only
528
two (or one) ventromedian supplements vs seven to
nine, and absence of a gubernaculum.
TYPE LOCALITY AND HABITAT
Dune slacks "vith vegetation hummocks in the Alex-
andria dune field, east of Sundays River mouth in Algoa
Bay, near Port Elizabeth, South Africa. Eleven females
and eleven males coUected during 1987 by A. McLa-
chlan. This is the same as the type Jocality of Haliplectus
algoensis Swart, Heyns & Furstenberg, 1992, and more
information about the nature of the dune slacks can be
found in Swart et al. (1992).
OTHER LOCALITIES
Three females, two males and several juveniles from
dune sands at Swartvlei, near Sedgefield, March and
November 1990 (RAU samples - KP 134 and 138). A
single male specimen in dune sands at Cape Agulhas,
the southernrnost tip of the African continent, 15 Octo-
ber 1988 (RAU sample KP 111). One female, three
males and four juveniles from dune sands at Strand-
fontein, August 1987 (RAU sample KP 76).
TYPE SLlDES
Holotype female on slide RAU type 290, paratypes on
slides RAU type 291-300 (from type locality in Alex-
andria dune field), and RAU slides 5634, 5638, 5845-
5848 (Sedgefield); 4284 (Cape Agulhas); and 3452-
3455 (Strandfontein). One female and one male depos-
ited in each of the following institutions: Laboratoriurn
voor Morfologie and Systematiek der Dieren, University
of Ghent, Belgium, and Laboratoire de Biologie Parasi-
taire, Protistologie, Helminthologie, Muséum National
d'Histoire Naturelle, Paris, France.
DISCUSSION
Study of the head region of S. capense n. sp. with LM
and especially with SEM showed that this species has
the usual complement of six inner labial papillae, six
outer labial papillae and four cephalic papillae. It is in-
conceivable that this will not be the same in aU Syn-
onchiu.m species, therefore there can be little doubt that
the papillae which Cobb (1920) labelled as six cephalic
papillae in his illustration of S. obtusum on page 291 are
in fact the outer labial papillae, and that he overlooked
the four cephalic papillae, which in ail probability are as
small and closely approximated to the outer labials as in
S. capense n. sp. In fact, in Chitwood's (1960) descrip-
tion of S. oblusum he does show the " double" papillae
in his Fig. 1C, although he does not mention labial or
cephalic papillae in his brief description (his Fig. lE is
less accurate). However, in his description of S. paci-
ficumy Yeates (1967) mentions" two rings, each of six
papillae, visible in en face view", without indicating
whether he regarded these as labial, or labial and cephal-
ic, and clearly indicating that he also overlooked the four
cephalic papillae. His Fig. 2A shows only two circlets
(= labial papillae), but not the four cephalic papillae.
Fundam. appl. NemaLOI.
Gerlach (1954) in his description of S. depressum men-
tions, and illustrates in his Fig. 3A, six labial and six
cephalic papillae « de même grandeur », indicating that
same as Cobb, he overlooked the cephalic papillae and
regarded the outer labials as six cephalic papillae. In
Gerlach's (1952) description of S. oblUsum he does not
illustrate the papillae accurately, but here he explicitly
states" zwei Kranze von Papillen, sechs Lippenpapillen
und sechs Kopfpapillen ". Interestingly, in his 1964 de-
scription of S. oblUsum he accurately portrays (in his Fig.
14 a) the six inner labial, six outer labial and four cephal-
ic papillae, and yet he talks of ten cephalic papillae. He
repeats this mistake in his 1967 description: " Es sind
zehn flache Kopfpapillen vorhanden ".
Regarding the large glandular structures associated
with the female reproductive system described above, it
is not sure whether this is a structure unique to S. ca-
pense, n. sp., or whether it is also present, but perhaps
less well-developed, in other Synonchium species. It may
well have been overlooked, since no previous author
gave a detailed description or illustration of the repro-
ductive system.
Cobb (1920) did not mention whether S. oblusum had
one or rwo testes, but apparently Chirwood (1960) re-
gards it as a single outstretched testis. Gerlach (1952,
1964, 1967) does not mention the male gonad in any of
his three descriptions of S. oblusum) neither in his de-
scription of S. clepressum. However, in S. paczjicum and
S. capense n. sp. there are rwo opposed, outstretched
testes, and we can safely assume that this will be the case
in all Synonchium species.
Key to species of Synonchium
- Tail conoid; amphids ùuee times as broad as high; man-
dibles with thIee reeth each S. depressurn Gerlach, 1954
- Tail bluntly rounded; amphids circlÙar or slightly broader
than high; manctibles with three or five reeth each .... 2
2 - Mandibles \Vith three teeth each; spinneret mostly indis-
tinCt or absent; cuticle without punctations ...
.................... S. capense n. sp.
VoI.IS,no6-1995
Synonchium capense n. sp.
- Mandibles \Vith five reeth each; spinneret ctistinet; cuticle
with punctations 3
3 - Mandibles with three large and [\Vo smaUeI reeth; male
with two inconspicuous venrromedian supplements; gu-
bernacuJum absent S. oblUsurn Cobb, 1920
- Mandibles with one large tooth flanked by [\vo smaller
teeth on each side; male with seven to nine venrromedian
supplements; gubernaclÙum present ..
......................... S. pacificum Yeares, 1967
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Synonchium capense n. sp. from South Africa (Nematoda : Cyatholaimidae)

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