Acta Parasitologica, 2005, 50(1), 74–79; ISSN 1230-2821
Copyright © 2005 W. Stefañski Institute of Parasitology, PAS
Clavellotis sebastidis sp. nov. (Copepoda, Lernaeopodidae)
parasitic on Sebastes oculatus Valenciennes, 1833
Stefański
from Argentina
Raúl Castro1* and M. Teresa González2
1Departamento
Acuicultura, Facultad de Recursos del Mar, Universidad de Antofagasta, Casilla 170, Antofagasta; 2Instituto de Ecología
y Evolución, Facultad de Ciencias, Universidad Austral de Chile, Casilla 567, Valdivia; Chile
Abstract
A new species of Clavellotis Castro et Baeza, 1984 (Copepoda, Lernaeopodidae) parasitic on Patagonian redfish, Sebastes
oculatus Valenciennes, 1833 from southern coast of Argentina is described and illustrated. The new species of Clavellotis differs from its congeners by the length of second maxilla, shape of the female trunk, length of genital process, and a combination of characters. The male also shows differences in the second maxilla, the maxilliped and in the shapes of the trunk and
genital process. This is the first record of Clavellotis from the southern Atlantic Ocean and also the first record on a Sebastes
species.
Key words
Copepoda, Lernaeopodidae, Clavellotis, new species, fish, Sebastes, Argentina
Introduction
Skóra
Among the copepods that parasitize marine fishes, the family
Lernaeopodidae includes 45 genera (Benz et al. 2000), someon teleost and others on elasmobranch fishes. All of them are
characterized by their mode of attachment by means of a bulla
at the end of the second maxilla (with the exception of Dendrapta Kabata, 1964, Schistobrachia Kabata, 1964 and Brianella Wilson, 1915). The bulla is inserted into the host tissue,
facilitating a strong and permanent attachment allowing the
copepod to have a range of action, depending upon the length
of the second maxilla, in order to obtain its food.
There is no record in the literature for lernaeopodids that
are parasitic on Sebastes in Argentinean marine waters. The
only lernaeopodids reported from Argentinean waters are Lernaeopoda bivia Leigh-Sharpe, 1930 on “Halaelurus bivius”
[valid name Schroederichthys bivius (Müller et Henle, 1838)],
from Puerto Deseado (Kabata 1986), and Lernaeopoda mustelicola Leigh-Sharpe, 1919 on Mustelus schmitti Springer,
1939 (cf. Brian 1944 after Etchegoin and Ivanov 1999).
The Sebastes species are parasitized in other latitudes by
some lernaeopodids, such as Neobrachiella robusta (Wilson,
*Corresponding
1912) (cf. Dojiri 1981, Kabata 1987). The study of Sebastes
oculatus collected in Argentine waters has permitted the detection of lernaeopodid specimens from the Clavella group
(Kabata 1979) attached to their branchial arches (gill rakers).
For the lernaeopodids, the male type gives an important clue
that permits the definition of the taxonomic position of some
specimens (Wilson 1915; Kabata 1979, 2004; Castro and
Baeza 1984). In this case, the male characteristics permit us to
identify the present specimens as belonging to the genus
Clavellotis Castro et Baeza, 1984. This genus includes eight
species (Kabata 1990) plus the most recent addition of C. briani (cf. Benmansour et al. 2001).
Characteristics of the female and male specimens are described, and their taxonomic identity is determined by comparison with all Clavellotis species, leading to the proposal of
a new species, C. sebastidis.
Materials and methods
Drawings were made with the aid of a camera lucida attached
to a stereomicroscope or compound microscope. Measure-
author: rcastro@uantof.cl
Clavellotis sebastidis sp. nov. on S. oculatus from Argentina
75
Śląski
2
1
4
5
3
Figs 1–4. Female Clavellotis sebastidis sp. nov.: 1. Female non-ovigerous, entire lateral view, with male attached; B – bulla, M – male,
SM – second maxilla, arrow indicating the genital process. 2. Female ovigerous, entire lateral; arrow indicating the genital process. 3. Female
trunk dorsal view; arrow indicating the genital process. 4. First antenna; W – whip, 1, 3, 4, 5, 6 – numbers of setae
Zdzisław
76
Raúl Castro and M. Teresa González
Stanisła
ments were made in micrometres, with a reticulated eye piece
attached to the microscope. The terminology adopted follows
that of Kabata (1979).
Results
Clavellotis sebastidis sp. nov. (Figs 1–14)
Female: Cephalothorax cylindrical, longer than trunk; latter
suboval with developed genital process. Some specimens with
short anal process protruding from genital process. Second
maxilla long, about as long as trunk or slightly shorter than
cephalothorax, fused at apex, bearing distally short bulla, with
rounded swelling on each side.
Measurements (based on 20 specimens): Cephalothorax
length 1702.6 (1281–2205), width 337 (256–462); second
maxilla length 1174.8 (974–1461), width 387 (231–641);
trunk length 1255 (949–1590), width 811.8; genital process
length 212.6 (103–282), width 174 (103–256); egg sac length
(n = 8), 947.5 (641–1103), diameter 362 (259–462).
Appendages: First antenna (Fig. 4) apparently three-segmented, distal armature with 5 visible elements (setae: 1, 3, 4,
5 and 6). Seta 6 longer than others.
Second antenna (Fig. 5): Exopod long, axis in line with
sympod, bulbous, armed with spinules on outer surface. Endopod apparently two-segmented, distal segment armed with
three spines, two of them of equal size, third smaller.
Mandible (Fig. 6) with three secondary teeth, dental formula P1S1, P1S1, P1S1, B4.
First maxilla (Fig. 7) biramous; exopod with two digitiform papillae, each bearing apical long seta; short seta at base
of dorsal papilla; exopod lateral, short, with two subequal apical setae. No other armature detected.
Second maxilla (Figs 1 and 2) as long as trunk and/or
cephalothorax, slender, with rounded lateral swellings at base,
fused at apex. Bulla short, typical for Clavellotis.
Maxilliped (Fig. 8): Robust corpus, myxa bearing single
seta. Subchela cylindrical, with spiniform process on lateral
surface, distally with basal seta and sparse denticulation on
distal part of inner margin; distal claw slightly curved.
Male (Fig. 9) typical of Clavellotis Castro et Baeza, 1984.
Body sack-like; trunk abbreviated, much smaller than cephalothorax, genital process prominent.
First antenna (Fig. 10A) three-segmented, basal segment
with long whip. Distal segment armature of 5 elements, seta
6 longer than others.
Second antenna (Fig. 10B): Exopod bulbous and long,
covered on distal outer surface with small spiniform processes and short spine; endopod much longer than exopod, with
two segments, distal segment with outer distal margin armed
with two spines, and a pad of short spinules ventrally, also pad
of short spinules at base of first segment.
Mandible (Fig. 11) with three secondary teeth, dental formula P1S1, P1S1, P1S1, B4.
First maxilla (Fig. 12): Endopod with two papillae, each
surmounted by long seta; short seta at base of dorsal papilla.
Exopod ventrolateral; short papilla with two setae of about
equal size.
Second maxilla (Fig. 13) globose, strong, slightly curved
claw closing against prominent inner part of corpus.
Maxilliped (Fig. 14) subrectangular, with long, slender
base, bearing two rows of spiniform processes, each row separated from other, but appearing fused in dorsal view.
Locality: Golfo San Jorge (43°S), Argentina.
Host: Patagonian redfish, Sebastes oculatus.
Habitat: Branchial arches (gill rakers).
Material deposited in the British Museum of Natural
History: holotype no. 2004.556; paratypes nos. 2004.557–
558, allotype no. 2004.559.
Etymology: The specific name sebastidis refers to the
generic name of the host.
Discussion
The males of the specimens recorded in this study show morphology typical of the Clavella group. Consequently, these
specimens can be assigned to Clavellotis Castro et Baeza,
1984, based principally on the males, which permit clear discrimination among all those genera within the Clavella group,
and fit well within the amended diagnosis of Kabata (1990).
To date, the genus Clavellotis included nine species: C. dilatata (Krøyer, 1863) type species, and 7 species that were
transferred from the genus Clavellopsis Wilson, 1915 by Kabata (1990): C. bilobata (Pillai, 1962), C. branchiostegi (Yamaguti, 1939), C. characis (Richiardi, 1880), C. fallax (Heller, 1856), C. pagri (Krøyer, 1863), C. sargi (Kurz, 1877),
C. strumosa (Brian, 1906), and a recently added C. briani
Benmansour, Ben-Hassine, Diebakate et Raibaut, 2001, plus
a tentative, unnamed member of this genus (Roubal 1981),
whose female was never fully described and more information
is required for a definitive decision on the status of this species
(Kabata 1990).
Among all species of Clavellotis, the new species differs
from a group that shares a well-developed aliform lateral projection from the cephalothorax base (C. bilobata, C. briani,
C. branchiostegi, C. dilatata, C. fallax and C. strumosa). The
remaining species are more closely related to the new species,
due to the presence of a subcircular lateral projection
(C. characis, C. pagri and C. sargi).
The new species can be differentiated from C. sargi because, in the latter, the female bears a very long genital process, and the trunk is subcircular. The male shows differences
in the trunk and genital process, in the second maxilla and in
the maxilliped shape. C. pagri also differs in the female trunk
shape and in the length of the second maxilla, which is longer
in the new species. Other differences are found in the male
second maxilla, maxilliped, and in the shapes of the trunk and
genital process.
The present specimens, parasitic on S. oculatus, can be
distinguished from C. characis by the length of the female
genital process, which is longer in C. characis, by the trunk
Clavellotis sebastidis sp. nov. on S. oculatus from Argentina
Roborzyński
rosbśźćv
shape, and especially by the length of the second maxilla,
which is shorter in C. characis. The male shows other differences in the length of the trunk and the genital process, as well
as in the shapes of the second maxilla and maxilliped.
77
fjad kadsććżć
Consequently, the presently described Clavellotis specimens cannot be considered conspecific with any of the previously mentioned species. The second maxilla is longer than
in those species. Clavellotis shows typically distinctive ap-
Figs 5–8. Female Clavellotis sebastidis sp. nov., appendages: 5. Second antenna; EN – endopod, E – exopod. 6. Mandible. 7. First maxilla;
E – exopod, EN – endopod. 8. Maxilliped; B – basal seta, C – corpus, CL – claw, D – denticles, SH – shaft
Raúl Castro and M. Teresa González
78
pearances in the trunk and genital process. This, in addition
to differences in the maxilliped and second maxilla, preclude
its inclusion within the previously described species of Clavellotis. The authors suggest the creation of a new taxon for
the specimens that parasitize S. oculatus; the name proposed
is Clavellotis sebastidis.
This is the first record of Clavellotis from the southern
Atlantic, and the first on Sebastes species.
Figs 9–14. Male Clavellotis sebastidis sp. nov.: 9. Male entire, lateral view; BC –
buccal cone, GP – genital process, SM – second maxilla, M – maxilliped. 10. First
antenna and second antenna; A – first antenna, B – second antenna, E – exopod,
EN – endopod, W – whip, 6 – seta six. 11. Mandible. 12. First maxilla. 13. Second
maxilla. 14. Maxilliped
Clavellotis sebastidis sp. nov. on S. oculatus from Argentina
Acknowledgements. The collection of the parasites of S. oculatus
from the Argentine coast was possible with economic support given
to M.T. González by the D.I.D. of the Universidad Austral de Chile
(project D-2003-09).
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