Acanthopharynx affinis Marion, 1870 (Nematoda: Chromadorida: Desmodoridae), a new record of the Atlantic Ocean

              Rev. Acad. Canar. Cienc, XXIII (Num. 3), 25-28 (20 11) (publicado en abril de 2012)
Acanthopharynx affinis Marion, 1870
(NEMATODA: CHROMADORIDA: DESiMODORIDAE),
A NEW RECORD OF THE ATLANTIC OCEAN
Rodrigo Riera'*, Jorge Xuiiez- & Maria del Carmen Brito-
' Centre de In\estigaciones Medioambientales del Atlantico (CIMA SL)
Arzobispo Elias Yanes. 44. 38206 La Laguna, Tenerife, Canary Islands, Spain
- Benthos Lab. Department of Animal Biology. Faculty of Biology
University of La Laguna. 38206 La Laguna. Tenerife. Canarv' Islands. Spain
*corresponding author: rodrigo(^cimacanarias.com
RESUMEN
Se recolecta por primera vez para el oceano Atlantico la especie de nematode Acau-thoparynx
affinis Marion 1870. anteriormente recolectada en el mar Mediterraneo. Se rea-liza
una descripcion de la especie, y se detallan las medidas de los caracteres taxonomicos
mas importantes. Ademas, se muestran datos sobre los factores sedimentarios de la locali-dad
de estudio.
Palabras clave: Nematoda. X^QsmodoviddiQ, Acanthophaiynx, \ ida libre. Tenerife, islas
Canarias.
ABSTRACT
The nematode species Acanthopaiyux affinis Marion 1870 is collected for the first
time in the Atlantic Ocean, fonnerly only recorded in the Mediterranean Sea. A description
and measurements of the most important taxonomical characters are presented. Furthennore,
abiotic data of the sampling station are reported.
Key words: Nematoda, Desmodoridae, Acanthophaiynx, free-living. Tenerife. Canar\'
Islands.
1. INTRODUCTION
The genus Acanthophaiynx Marion, 1 870 is characterized by having a set off head and
developed cephalic capsule. 4 outer labial setae located at the median region of the head,
sometimes at the same level as cephalic ones. Amphids situated in the cephalic capsule. Pre-cloacal
supplements tubular. Males with one reflexed testis and females with two reflexed
ovaries. This genus resembles Desmodora, however, oesophageal bulb is very long, almost
half length of oesophagus in Acanthophaiynx (Piatt & Warwick [3]). The most important tax-
•
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onomic characters of this genus are (i) pre- and postoamphidial setae, (ii) amphid size, (iii)
presence or not of supplements and postanal papillae (Wieser [6]).
Up to now, the genus Acanthophaiynx Marion, 1870 comprises 12 species: A. affinis
Marion, 1870, A. brachycapitata (Allgen, 1947), A. denticulata Wieser, 1954, A. japonica
Steiner & HoeppH, \926,A. merostomacha (Steiner, 1921),^. micans (Eberth, 1873),^. mi-cvamphis
Stekhoven, 1942, A. mida (Cobb, 1920), A. peravmata Marion, 1870, A. rigida
Stekhoven, 1950,^. setosissima Stekhoven, 1943 m\dA. similis (Allgen, 1932).
2. MATERIAL AND METHODS
Samples were collected in the intertidal and shallow subtidal soft-bottoms of Los Abri-gos
(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 10% formalde-hyde
in seawater for one day and decanted through a sieve of 63 mm mesh size, and posteri-orly
preserved in 70% ethanol. Specimens were mounted in jelly glycerine gel and drawings
of these were done using a camera lucida on a Leica DMLB microscope equipped with No-marski
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; m, male; s', spicule length di-vided
by anal body diameter; %V, position of vulva as a percentage ofbody length from anterior.
3. SYSTEMATICS
CHROMADORIDA Chitwood, 1933
CHROMADORINA Filipjev, 1928
DESMODORIDAE Filipjev, 1922
Acanthophaiynx Marion, 1870
Acanthophaiynx afflnis Marion, 1870
(Fig. l,Tab. 1)
Acanthopharynx affinis Marion [1]: 36-37, pi. K, fig. 4-4b; Schuumars-Stekhoven [4]: 243,
fig. 13a-c; Palacin [2]: 33, fig. 2e-f
Meristic data and studied material.- Abrigos intertidal: november 2000, 1 male (ml); Cristianos in-tertidal:
august 2000. 1 male (m2); Cristianos subtidal: October 2000, 1 male (m3).
Description.-
Male: Body slender and tappering towards both ends. Head slightly round, not set off and
cephalic capsule evident. Cuticle with fine transversal striations, lateral differentiation absent.
Amphids are 25% of the cbd, unispiral, located at 5 \xm from anterior end. Buccal cavity
small, with one noticeable dorsal tooth. Inner labial setae absent. Outer labial and cephalic
setae equal, 0.3 cephalic diameters long, very numerous (20-30). These setae are situated at
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the same level and located in the
median part of the head capsule.
Subcephalic setae 4-7 |im long, situ-ated
at 6-12 |im from the body
anterior end. Pharynx slender and
cylindrical. Oesophageal bulb very
long. Ventral gland and nerve ring
not seen.
The reproductive system is
monorchic with one retlexed testis.
Spicules are 1 anal diameter long,
paired and arcuated, with a capitu-lum.
Gubemaculum 0.4 anal diame-ters
long, small and without apoph-ysis.
9-14 tubular precloacal
supplements. Tail 1.5 anal diameters
long, short and conical with trun-cated
posterior tip. Caudal setae lack-ing.
Spinneret inconspicuous.
Discussion.
belonging to
ml m2 m3
Total body length 1442.9 2028.6 1800
a 23.9 31.6 25.2
b 6.3 7.1 7.5
c 22.9 21.8 20.3
Cephalic diameter 25.9 35.7 30
Inner labial setae 31 35.7 40
Outer labial setae - - -
Cephalic setae 7.1 7.1 7.1
Subcephalic setae 7 8.6 10
Buccal ca\ it\' diameter 4 6.4 7.1
Amphid diameter 5.7 12.9 10
Amphid height 8.6 8 8
Amphid from anterior 4.3 3 4
Phar\ n\ length 5.7 7 8
Phar> n.\ cbd 228.6 285.7 239.3
Maximum body diameter 57.1 60.7 60.7
VuK a from anterior 60.3 64.3 71.4
%V
Spicule length 43 58.2 50.2
Gubemaculum length 24.3 18.6 35.7
s" 1 1.4 1.1
Tail length 63 92.9 88.6
Anal body diameter 41 60.7 53.6
c' 1.5 1.5 1.6
Spicule length Tail length 0.7 0.9 0.-
Table
in [xm.
Measurements of Acanthoplniiyn.x affinis Marion. 1870
The different species
the genus Acan-thophannx
can only be distin-guished
after subtile taxonomic
characters, since they resemble each
other very much (Schuurmas-
Stekhoven [5]). Howe\er. canarian
specimens fit well with mediter-ranean
individuals (Palacin [2])
though several differences can be
discerned between them. The
spicules in canarian specimens are less developed than mediterranean indi\ iduals, as well as,
the development of the capitulum (anterior end of the spicules). Gubemaculum is slender in
canarian specimens and almost triangular in mediteiTanean individuals. However, the fomier
differences could be partially due to a bad fixation of individuals in gelly glycerine. Moreover,
mediterranean specimens are larger than canarian (2.45-2.93 V5 1.44-2.03 mm), thus, there
are differences in De Man indexes betw een both groups.
Ecology.- In Los Abrigos intertidal this species was collected in well sorted medium grained
sands with an organic matter content of 0.88% and 4.44° o of carbonates. In Los Cristianos in-tertidal
this species was collected in well sorted fine grained sands with an organic matter
content of 0.39% and 25.13% of carbonates. In the subtidal of this location, this species was
recorded in well sorted fine grained sands with an organic matter content of 0.64° o and 25.30%
of carbonates.
Distribution.- Mediterranean Sea (Marion [1], Schuumars-Stekho\en [4], Palacin [2]). This
species is first recorded in the Atlantic Ocean.
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Figure 1.- Acanthophaiynx affinis Marion, 1870. Male. A. Anterior end. B. Posterior end. Scale = 30 |im.
4. ACKNOWLEDGEMENTS
The first author (R.R.) thanks P.J. Somerfield (Plymouth Marine Laboratory, UK) for
taxonomic advice during the beginning of his research on free-living marine nematodes. Au-thors
also acknowledge Dr. Catalina Pastor de Ward (Centro Nacional Patagonico, Argentina)
for interchange of ideas.
5. REFERENCES
[1] MARION, A.F: 1870. Addition aux recherches sur les nematoides libres du golf de Mar-seille.
^/7/2. Sci. Nat. 14(1): 1-16.
[2] PALACIN, C. 1985. Nematodos marinos de las algas fotofilas del litoral de Menorca II.
Chromadorida y Monhysterida. Misc. ZooL, 9: 31-48.
[3] PLATT, H.M. & R.M. WARWICK. 1 988. Free-living marine nematodes. Part II. British
Chromadorids. Synopses of the British Fauna n°38: 1-502.
[4] SCHUUMARS-STEKHOVEN, J.H. 1942. The free-living marine nematodes of the
Mediterranean. II. The Balearic Islands. Zoologische Mededelingen, 23: 229-262.
[5] SCHUUMARS-STEKHOVEN, J.H. 1 950. The free-living marine nemas of the Mediter-ranean.
I. The Bay of Villefranche. Mem. Inst. R. Sci. Nat. Belg. 2 Ser(17): 1-220.
[6] WIESER, W. 1954. Free-living marine nematodes. II. Chromadoroidea. Acta. Univ.
Limd.,50{\6y. 1-148.
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