The family Chromadoridae Filipjev, 1917 (Nematoda, Chromadorida) from two beaches of Tenerife (Canary Islands, NE Atlantic Ocean)

              Rev. Acad. Canar. Cienc, XXI (Nums. 3-4), 49-57 (2009) (publicado en septiembre de 2010)
THE FAMILY CHROMADORIDAE FILIPJEV, 1917 (NEMATODA,
CHROMADORIDA) FROM TWO BEACHES OF TENERIFE
(CANARY ISLANDS, NE ATLANTIC OCEAN)
Rodrigo Riera'*, Jorge Niinez^ & Maria del Carmen Brito-
' Centra de Investigaciones Medioambientales del Atlantico (CIMA SL), Arzobispo Elias Yanes, 44
38206 La Laguna, Tenerife, Canary Islands, Spain
^ Benthos Laboratory, Department of Animal Biology, Faculty of Biology, University of La Laguna
38206 La Laguna, Tenerife, Canary Islands, Spain
* corresponding author: rodrigo@cimacanarias.com
RESUMEN
Tres especies pertenecientes a la familia Chromadoridae Filipjev, 1917 se recolec-taron
durante la realizacion de un estudio ecologico sobre el intermareal y submareal somero
de dos playas de Tenerife. Dos de estas especies fueron determinadas a nivel generico:
Actinonema sp y Hypodontolaimns sp, debido a la ausencia de adultos en el primer genero
y las malas condiciones de conservacion del segundo. La tercera especie identificada fue
Ptycholaimellus ponticus (Filipjev, 1922). Se aportan las descripciones, figuras y datos
meristicos de las tres especies, asi como datos ecologicos de las estaciones de muestreo.
Palabras clave: Nematoda, Chromadoridae, vida libre, fondos blando, Tenerife, Islas
Canarias.
ABSTRACT
Three species of the family Chromadoridae were collected during an ecological study
of the intertidal and shallow soft-bottoms of two beaches in Tenerife. Two of these species
were determined to genus level: Actinonema sp and Hypodontolaimus sp, due to the lack of
adult specimens in the first genus and the presence of aduhs in poor conditions in the sec-ond.
Another species recorded was Ptycholaimellus ponticus (Filipjev, 1922). Descriptions,
figures and meristic data of each species are presented, as well as, autoecological data from
sampling stations.
Key words: Nematoda, Chromadoridae, free-living, soft-bottoms, Tenerife, Canary
Islands.
49
INTRODUCTION
The family Chromadoridae Filipjev, 1917 is established using the following two
holapomoiphies: 1) there is always only a single, anterior testis; 2) the anterior ovary is
always situated in the right of the intestine and the posterior gonad always to the left of it
(Lorenzen [4]). Additional features are the cuticle always striated and ornamented. Inner
labial sensilla minute or inconspicuous. 6 shorter outer labial setae and 4 larger cephalic
setae arranged in two separate circles, except in the subfamily Euchromadorinae. Males of
many species have cup-shaped or tubular precloacal supplements or lacking.
Several species belonging to the family Chromadoridae were collected during an eco-logical
study of the soft-bottoms on the south coast of Tenerife. A detailed study revaled that
these specimens belong to three different species: Actinonema sp., represented only by a
juvenile, Hypodontolaimus sp. represented by one juvenile and one male in poor conditions
and Ptycholaimellus ponticus (Filipjev, 1922) represented by two females.
MATERIAL AND METHODS
Samples were collected in the intertidal and shallow subtidal, 3 m deep, soft-bottoms
of Los Abrigos (SE Tenerife) and Los Cristianos (SW Tenerife). PVC cores of 4,5 cm of
inner diameter were taken to a depth of 30 cm in the sediment. These samples were fixed
with 1 0% formaldehyde in seawater for one day and decanted through a sieve of 63 mm
mesh size, and posteriorly preserved in 70% ethanol. Specimens were mounted in glycerine
gel and drawings of these were done using a camera lucida on a Leica DMLB microscope
equipped with Nomarski interference contrast. All measurements are in micrometers and
curves structures are measured along the arc.
Abbreviations used in the text are: a, body length divided by maxium body diameter; b,
body length divided by pharyngeal length; c,body length divided by tail length; c', tail length
divided by anal body diameter; cbd, corresponding body diameter; s', spicule length divided
by anal body diameter; %V, position of vulva as a percentage of body length from anterior.
SYSTEMATICS
Subclass CHROMADORIA Pearse, 1942
Order CHROMADORIDA Chitwood, 1933
Suborder CHROMADORINA Filipjev, 1918
Family CHROMADORIDAE Filipjev, 1917
GQrms Actinonema Cohh, \92Q
This genus is characterized by having a head not set off 6 outer labial setae and 4
cephalic ones. Cuticle heterogeneous with lateral differentiation. Amphids elliptical with
double contour. Spicules simple and arcuated. Lateral pieces of the gubemaculum "L-shaped".
Males with one outstretched ovary and females with two opposed and reflexed
ovaries. Precloacal supplements lacking.
50
Seven species of this family have been so far described: Actinonema celtica Boucher,
1976, A. fidatum Vitiello, 1970, A. longicaudatum Steiner, 1918, ^. pachydermatum Cobb,
1920, A. grafi Jensen, 1991, A. paraceltica Muthumbi & Vincx, 1998 and A. smolae
Muthumbi & Vincx, 1998.
Actinonema sp.
(Fig. l,Tab. 1)
Meristic data and studied material: Cristianos subtidal: March 2001, 1 juvenil (Juvenil 1).
Description: Males and females not found.
Juvenil: Body slender, tappering towards both ends. Head round and not set off. Cuticle
annulated, with lateral differentiation 3 ^m wide at the level of the posterior end of the phar-ynx.
Amphids are 65% of the corresponding body diameter in width, simple and elliptical
with double contour, located at 6 jum from the anterior end. Buccal cavity conical without
noticeable dorsal tooth. Inner labial setae lacking. Outer labial setae inconspicuous and 6
cephalic setae 0.5 cephalic diameters long, situated in the median part of the head. Pharynx
slender and cylindrical.
Reproductive system not developed. Tail 8 anal diameters long, filiform in most of its length,
posterior tip acuminated. Caudal setae lacking. Spinneret poorly developed.
Discussion: The genus Actinonema closely resembles the genus Rhips Cobb, 1920, but can be
differenciated in having simple or lacking spicules and the genus Rhips presents jointed
spicules (Muthumbi & Vincx [5]). Canarian specimen presents more affmities with females of
the genus Actinonema. However, the studied individual differs from the remaining species of
Actinonema in having a smaller amphid and larger cephalic setae (0.5 cephalic diameters long).
Ecology: This species was collected in fine sands (Q50 = 0.16), with a very good selection
(So = 0.59). The organic matter content was 0.81% and 24.10% of carbonates percentage.
Genus Hypodontolaimus De Man, 1886
This genus is characterized by having homogeneous cuticular ornamentation with lat-eral
differenciation formed by two or four longitudinal files of punctations. Buccal cavity
with a hollow dorsal tooth "S-shaped" and dorsal apophysis. Oesophageal bulb developed.
Precloacal supplements cup-shaped, sometimes absent. Males with one anterior testis and
females with two reflexed ovaries.
Hypodontolaimus sp.
(Fig. 2, Tab. 2)
Meristic data and studied material: Abrigos subtidal: May 2000, 1 juvenil (Juvenil 1); Cristianos
subtidal: April 2001, 1 male {d\).
51
Description:
Male: Body slender, tappering towards both ends. Head round and slightly set off. Cuticle
ornamented with homogeneous punctations and lateral differentiation formed by two longi-tudinal
files of punctations (1 ^im wide at the level of the median part of the pharynx).
Amphids not seeen. Buccal cavity large and conical with a developed dorsal tooth. 6 inner
labial setae lacking. Outer labial setae 4 |Lim long and 4 cephalic setae 0.5 cephalic diame-ters
long, located at the anterior part of the head. Subcephalic setae absent. Pharynx slender
and cylindrical.
The reproductive system is monorchic, with one anterior testis. Spicules 0.6 anal
diameters long, paired, arcuated, with a capitulum. Gubemaculum 0.3 anal diameters long,
narrow and without apophysis. Precloacal supplements absent. Tail 1.7 anal diameters long,
conical and with an acuminated posterior tip. Caudal setae lacking. Spinneret developed.
Females not found.
Discussion: The studied material is related to the genera Chromadorita, Megadontolaimus
and Hypodontolaimus, belonging to the latter due to the presence of lateral differenciation
and homogeneous cuticle (Pastor de Ward [6]). Hypodontolaimus sp. is characterized by
having a short tail, lacking somatic setae and precloacal supplements. This species was deter-mined
to genus level due to the poor conditions and low number of collected individuals.
Ecology: In the subtidal of Los Abrigos this species was recorded in medium sands (Q50 =
0.34), with a very good selection (Sg = 0.83). The organic matter content was 0.50% and
5.47% of carbonates percentage was. In the subtidal of Los Cristianos was collected in fine
sands (Q50 = 0. 16), with a very good selection (Sq = 0.56). The organic matter percentage was
0.53%) and 22.56%) of carbonates content.
Genus Ptycholaimellus Cobb, 1920
This genus is characterized by having a hollow dorsal tooth "S-shaped". Double
oesophageal bulb. Precloacal supplements absent. Males with one outstretched and anterior
testis. Females with two opposed and reflexed ovaries.
16 species of this genus have been so far described: P. adocius Daschenko &
Belogurov, 1984, P. boucheri Jensen & Nehring, 1992, P. carinatus Cobb, 1920, P. inae-quibulbus
(Aminova & Galtsova, 1978), P. jacobi Jensen & Nehring, 1992, P. jenseni
(Gerlach, 1951), /! hibernus Eskin & Hopper, 1985, P. lizardiensis Decraemer & Coomans,
1978, P. macrodentatus Timm, 1961, P. monodon (Stekhoven, 1942), P. pandispiculatus
(Hopper, 1961), /^ penninae Muthumbi & Vincx, 1998, P. pondcus (Filipjev, 1922), P. slack-smithi
(Inglis, 1969), P. setosus Pastor de Ward, 1984 and P. vincxae Jensen & Nehring, 1992.
Ptycholaimellus pondcus (FilipiQY, 1922)
(Fig. 3, Tab. 3)
Hypodontolaimus ponticus Filipjev [1]: 132, fig. 14 a-c.
Ptycholaimellus ponticus.- Gerlach [2]: 109, fig. 3 a-h; Jensen & Nehring [3]: 242, fig. 2 d-f,
3; Muthumbi & Vincx [5]: 138, fig. 10 a-g.
52
Meristic data and studied material: Cristianos intertidal: November 2000, 2 females (9I
and 92).
Description:
Males not found.
Female: Body slender, tappering towards both ends. Head slightly round, not set off and
without cephalic capsule. Cuticle annulated with homogeneous punctations and heteroge-neous
lateral differentiation. Amphids inconspicuous. Buccal cavity large, with a cuticular-ized
and developed dorsal tooth. Inner labial setae lacking. Outer labial setae difficult to dis-cern.
4 cephalic setae 0.5 cephalic diameters long, located at the anterior half of the head.
Subcephalic setae absent. Pharynx slender and cylindrical. Ventral gland and nerve ring not
seen.
The reproductive system is diorchic with two reflexed ovaries. Vulva located at 48.5-54.3%
of the total body length. Tail 3 . 1 anal diameters long, cylindrical and filiform in its posteri-or
part, with a round tail tip. Caudal setae absent. Spinneret poorly developed.
Discussion: Canarian specimens agree well with the description of Jensen & Nehring [3].
This species is characterized by having a narrow body, cephalic setae shorter than one head
diameter, subventral teeth poorly developed, oesophageal bulb doble and cuticle pattern het-erogeneous.
British specimens present a non filiform tail and slightly larger (3.5-4.4 anal
diameters long) (Piatt & Warwick [7]) compared to the Canarian specimens.
Ecology: This species was collected in fine sands (Q50 = 0.17), with a very good selection
(So = 0.68). The organic matter content was 0.81% and carbonates percentage was 19.49%.
Distribution: Cosmopolitan (Jensen & Nehring [3]). This species is first recorded in the
Canary Islands.
ACKNOWLEDGEMENTS
The first author (R.R.) thanks P.J. Somerfield (Plymouth Marine Laboratory, UK) for
taxonomical advice during the beginning of his research on free-living marine nematodes.
Authors also acknowledge Dr. Catalina Pastor de Ward (Centro Nacional Patagonico,
Argentina) for constructive comments and suggestions.
REFERENCES
[1] FILIPJEV, I. 1922. Encore sur les Nematodes libres de la Mar Noire. Trudy Stavropol.
Sel. Khoz. Inst, 1: 83-184.
[2] GERLACH, S. 1951. Revision der Metachromadoracea, einer Gruppe freilebender
mariner Nematoden. Kieler Meeresforsch., 8: 59-75.
[3] JENSEN, R & S. NEHRING. 1992. Review of Ptycholaimellus Cobb (Nematoda,
Chromadoridae), with descriptions of three species. Zool. Scri., 21(3): 239-245.
53
[4] LORENZEN, S. 1994. The phylogenetic systematics offreeliving nematodes. The Ray
Society (ed.), London, 383 pp.
[5] MUTHUMBI, A. & M. VINCX. 1998. Chromadoridae (Chromadorida: Nematoda)
from the Indian Occean: Difficulties in moq^hological identification of Actinonema
Cobb, 1920 and Rhips Cobb, 1920. Hydrobiologia, 155-167.
[6] PASTOR DE WARD, C. 1984. Ptycholaimellus setosus sp. nov. Nueva especie de
nematodo marino de vida libre (Chromadoridae, Hypodontolaiminae) de Puerto
Deseado, Santa Cruz, Argentina. Neotropica, 30(83): 11-18.
[7] PLATT, H.M. & R.M. WARWICK. 1988. Free-living marine nematodes. Part II.
British Chromadorids. Kermarck, D.M. & R.S. Barnes (eds.). Cambridge University
Press. London, 501 pp.
54
FIGURES AND TABLES
Table 1.-
Measurements of Actinonema sp in jLim.
Juvenil 1
Total body length 1185.7
a 30.2
b 15.1
c 6
Cephalic diameter 11.4
Inner labial setae -
Outer labial setae -
Cephalic setae 5
Subcephalic setae -
Buccal cavity diameter 8.6
Amphid diameter 8.6
Amphid height 4.3
Amphid from anterior 10
Pharynx length 78.6
Pharynx cbd 28.6
Maximum body diameter 39.3
Vulva from anteriorr
%V
Spicule length
Gubemaculum length
Tail length 196.4
Anal body diameter 25
c' 7.9
Spicule length/Tail length
Figure 1.- Actinonema sp. Juvenil. A. Anterior end. B. Posterior end. Scale A = 15 fim, B = 20 \xm.
55
Table 2.-
Measurements of
Hypodontolaimiis sp in |um.
cT 1 Juvenil 1
Total body length 971.4 1157.1
a 19.4 20.3
b 3.8 4.1
c 19.8 13.5
Cephalic diameter 31 21.4
Inner labial setae -
Outer labial setae 4 -
Cephalic setae 15.6 -
Subcephalic setae - 7.1
Buccal cavity diameter 14.3 17.1
Amphid diameter 11 17.1
Amphid height 11.4 -
Amphid from anterior 8.6 -
Pharynx length 257.1 285.7
Pharynx cbd 39.3 25
Maximum body diameter 50
Vulva from anteriorr
%V
Spicule length 16
Gubemaculum length 11.4
s' 0.6
Tail length 49 85.7
Anal body diameter 29 46.4
c' 1.7 1.8
Spicule length/Tail length 0.3
>A>/V/
KI /--\ /^ / V -J B ^ - in n ^ H 1
>j _ -^ m
\ • * B :ri h\ ~^.V-ri
h- — ~-::i b^ \o . =-
^
~~^
: --—. ~^ K
6
°
:,-_
f ^ : o - ~^
V::;J:..:l:^
: •:';...',•.•.•::•; : : •..•, ::.'.":::
Figure 2.- Hypodontolaimiis sp. Male. A. Anterior end. B. Posterior end. Scale A = 20 ^m, B = 15 |im.
56
Table 3.-
Measurements of
PtycholaimeUus ponticus in |Lim.
cT 1 92
Total body length 1185.7 1028.6
a 18.5 16.9
b 6.9 5.5
c 7.1 7.8
Cephalic diameter 25.7 22.9
nner labial setae - -
Outer labial setae - -
Cephalic setae 14 15
Subcephalic setae - -
Buccal cavity diameter 11.4 10
Amphid diameter - -
Amphid height - -
Amphid from anterior - -
Pharynx length 171.4 185.7
Pharynx cbd 50 53.6
Maximum body diameter 64 60.7
Vulva from anteriorr 644.1 500
%V 54.3 48.6
Spicule length
Gubemaculum length
s'
Tail length 167.9 132.1
Anal body diameter 53.6 42.9
c' 3.1 3.1
Spicule length/Tail length
B
Figure 3.- PtycholaimeUus ponticus. A. Anterior end. B. Posterior end. Scale = 22 |im.
57