Redescription of Lepeophtheirus marginatus Bere, 1936 (Copepoda: Caligidae) and relegation of L. christianensis Wilson, 1944 and L. orbicularis Shiino, 1960 as its synonyms

10 Pages·2001·3.9 MB·

by  Ju-Shey Ho

PROCEEDINGS OFTHE BIOLOGICAL SOCIETY OF WASHINGTON
114(4):897-906. 200L
Redescription of Lepeophtheirus marginatus Bere, 1936 (Copepoda:
Caligidae) and relegation of L. christianensis Wilson, 1944 and
L. orbicularis Shiino, 1960 as its synonyms
Ju-shey Ho and Samuel Gomez
(J-SH) Department ofBiological Sciences, California State University,
Long Beach, California, 90840-3702, U.S.A;
(SG) Institute de Ciencias del Mar y Limnologia, Unidad Academia Mzatlan,
Joel Montes Camarena s/n, Ap. Postal 811, C.P. 82040, Mazatlan, Sinaloa, Mexico
—
Abstract. Lepeophtheirus marginatus Bere, 1936 is redescribed based on
examination oftype specimens. Studying the type materials ofL. christianensis
Wilson, 1944 and L. orbicularis Shiino, 1965 from sea catfish (Galeichthyes
sp.) collected in the Gulf of Mexico and Peru, respectively, led us to recom-
mend relegating both of them as synonyms of L. marginatus Bere.
In their report on a new species of Le- ural History, Smithsonian Institution in
peophtheirus parasitic on the bullseye puff- Washington, D.C. and Faculty of Biore-
er (Sphoeroides annulatus Jenyns) taken off sources, Mie University in Tsu, Japan were
Sinaloa, Mexico, Ho et al. (in press) sus- cleared in lactic acid for 1 hr before ex-
pected that L. christianensis reported by amination. Two specimens (one female and
Wilson (1944) may be synonymous with L. one male) of L. marginatus from USNM
marginatus Bere, 1936, because these nom- 79163 were dissected in a drop of glycerin
inal species resemble one another and prob- and the removed body parts and append-
ably were reported from the same species ages were mounted on slides using glycerin
ofsea catfish (Galeichthys sp.) caughtatthe as mounting medium and examined using a
same locality (offPass Christian, Mississip- compound microscope. All drawings were
pi). Therefore, type specimens of both spe- made with the aid of a camera lucida. In
cies deposited at the National Museum of this report a full description is given of the
Natural History, Smithsonian Institution in female and only those parts and appendages
Washington, D.C. were examined. Unex- showing sexual dimorphism are given of
pectedly, in the process of reviewing the the male.
species ofLepeophtheirus reported fromthe
sea catfish, it was discovered that not only Lepeophtheirus marginatus Bere, 1936
is L. christianensis synonymous with L. Figs. 1-6
marginatus, but also is L. orbicularis Shi- —
ino, 1965. Material examined. Type-material 1 ?
Based on these studies we herein rede- and 1 S (USNM 69860) from "outside
scribe L. marginatus and then discuss the skin" of Arius felis (Linnaeus) (= Galei-
establishment ofL. christianensis andL. or- chthys felis) collected at Englewood, Flor-
bicularis as junior synonyms ofL. margin- ida and another collection containing 3 $
atus. 9, 2 (? (?, and 1 young 2 (USNM 79163)
from Lemon Bay, Florida (no host desig-
Materials and Methods nated on label).
The specimens kept in 70% ethanol in Female.—Body (Fig. lA) 3.12 (2.94-
the collections ofNational Museum ofNat- 3.44) mm long, excluding setae on caudal
PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON
rami. Cephalothoracic shield nearly as long large, with transverse ridge across middle
(1.59 mm) as wide (1.43 mm), excluding region and cuneiform process on medial
marginal hyaline membranes. Fourth pedi- surface; slender, distal segment (brachium)
ger distinctly wider (373 ixm) than long carrying small subterminal process on outer
(193 |jLm). Genital complex (Fig. IB) slight- edge and 2 unequal elements (calamus and
ly longer than wide (942 X 878 ixm) and canna) terminally and subterminally. Max-
scattered with setules in central part ofdor- illiped (Fig. 2E) 2-segmented; proximal
sal surface and posteroventral surface near segment (corpus) largest, with basal flange
leg 5; median portion of anterior margin on medial surface; distal segments sharply
protruded to form a short stem thatconnects pointed claw carrying small knob in prox-
to 4th pediger, posteroventral portion be- imal region and simple, medial seta in mid-
tween 5th legs with or without shield-like dle region. Sternal furca on dissected spec-
cement plate (originating from a male with imen (Fig. 2F) with bluntly tipped tines
whom female mated) holding spermato- bearing marginal hyaline membranes, but
phores. Abdomen (Fig. IB) not clearly sep- tines of other specimens appears spatula-
arated from genital complex, distinctly wid- like as shown in Fig. 6C.
er than long (210 X 388 jxm) and with con- Armature on rami oflegs 1-4 as follows
vex sides. Caudal ramus (Fig. lA, B) small, (Roman numerals indicating spines and Ar-
wider than long (51 X 70 jxm), carrying 3 abic numerals, setae):
short (mediodorsal seta broken off on both
Exopod Endopod
rami in dissected specimen) and 3 long plu-
mose setae (broken off on both rami in dis- Leg 1 I-O; III, I, 3 (vestigial)
sected specimen). Egg sacs (not shown in Leg 2 I-l; I-l; II, 5 0-1; 0-2; 6
Fig. lA) longer than half body length. Leg 3 I-l; I, II, 5 0-1; 6
Frontal plate (Fig. lA) with 1 setule on Leg 4 I-O; I-O; III (absent)
anterior margin near midline. Antennule
(Fig. 2A) 2-segmented; proximal segment Leg 1 (Fig. 3A) protopod with plumose
with 27 plumose setae on anterodistal sur- outer seta and another plumose inner seta;
face, distal segment 2.69 times longer than endopod short, bluntly tipped pinnate pro-
wide, with isolated seta about midway on cess; first segment of exopod with row of
posterior margin and 11 setae plus 2 aesth- setules on posterior edge and short spini-
etascs on distal margin. Antenna (Fig. 2B) form seta at anterior-distal corner; middle 2
3-segmented; proximal segment smallest, of 4 terminal elements on last segment of
with bluntly pointed postero-medial pro- exopod with accessory process, 3 terminal
cess; 2nd segment robust, with ventral cor- elements bearing crescent membrane ter-
rugated pad near tip; distal segment with minally on both sides assuming spoon-like
sharply pointed, bent tip, with small seta in structure, and 3 posterior plumose setae
proximal region and slender seta in middle short. Leg 2 (Fig. 3B) coxa small, with
region. Postantennal process (Fig. 2B) com- large plumose seta on posterior edge; basis
prising massive, globular base with 2 setu- with small, naked outer seta; both lateral
le-bearing papillae and broadly rounded and medial edge of protopod with large
shaft. A spherical outgrowth located be- marginal membranous fringe, proximal lat-
tween bases of antenna and postantennal eral spines on third segment of exopod
process. Mandible (Fig. 2C) with 4 sec- semipinnate with naked anterior side, next
tions, bearing 12 teeth on medial margin of spine pinnate and appearing setiform. Leg
distal blade. Maxillule (Fig. 2B) consisting 3 (Fig. 4A) protopod with large lateral and
oflong, slender, pointed process andpapilla posterior marginal membranous fringe in
with 3 unequal setae. Maxilla (Fig. 2D) 2- addition to lateral and medial plumose se-
segmented; proximal segment (lacertus) tae. Both rami 2-segmented; proximal seg-
VOLUME 114, NUMBER 4 899
i^C^-^-.
mm
1 500pm
Fig. 1. LepeophtheirusmarginatusBere, 1936. Female. A, habitus, dorsal. B, genitalcomplexandabdomen,
ventral.
ment ofexopod round, with marginal mem- seta and small process tipped with 3 plu-
branous fringe membrane and slender seti- mose setae.
form process; second and terminal seg- Male.—Qody (Fig. 5A) 2.27 (1.90-2.48)
mm
ments incompletely fused, with 2 setules long, excluding setae on caudal rami.
proximal to lateral spines on terminal seg- Cephalothoracic shield about as long (1.19
ment. Leg 4 (Fig. 4B) protopod with short, mm) as wide (1.13 mm), excluding margin-
naked distal-lateral seta; pectens on exopod al hyaline membranes. Genital complex
segments at insertion of each lateral spine (Fig. 5C) longer than wide, 916 X 786 ixm,
(Fig. 4C). sparsely covered with setules on dorsal sur-
Leg 5 (Fig. 4D) represented by pinnate face and lateral margins; ventral surface
900 PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON
IOOmiT!
Fig. 2. Lepeophtheirus marginatus Bere, 1936. Female. A, antennule (not showing all setae), dorsal. B,
antenna, postantennal process, and maxillule; ventral. C, mandible. D, maxilla. E, maxilliped. F, sternal furca.
showing two posterolateral lobes bearing to maxillule (A2 in Fig. 6A). Dentiform
leg 6 at their tip. Abdomen (Fig. 5C) short process of maxillule with small protuber-
and slightly wider (488 |xm) than long (461 ance near base (A2 in Fig. 6A). Corpus of
fxm). Caudal ramus (Fig. 5B) wider (68 maxilliped (Fig. 6D) with 2 transverseridg-
fjLm) than long (50 |xm). Antenna (Al in es near base; shaft bearing subspherical
Fig. 6A) 3-segmented; proximal segment protuberance basally and spiniform setadis-
with large corrugated pad; middle segment tally; claw with denticulate medial protru-
largest, robust and armed with 2 corrugated sion near base (see insert drawing in Fig.
pads (Fig. 6B); terminal segment prehen- 6D). Sternal furca (Fig. 6C) with broad,
sile, quadrifurcate distally and armed with spatula-like tines. Leg 5 (Fig. 5C) consist-
2 spiniform setae. Corrugated pad on ster- ing ofsmall plumose seta andpapillatipped
num (A3 in Fig. 6A) posterior and medial with 1 simple and 2 plumose setae located
VOLUME 114, NUMBER 4 901
100pm
B
100|jm
Fig. 3. Lepeophtheirus marginatus Bere, 1936. Female. A, leg 1, anterior. B, leg 2, anterior.
on lateral side of genital complex. Leg 6 found in L. orbicularis Shiino and L. sim-
(Fig. 5C) represented by 3 plumose setae at plex Ho, Gomez & Fajer-Avila (2001).
tip of ventral ridge on genital complex. However, L. simplexis distinguishable from
L. marginatus in the shape of the genital
Discussion complex (oval in L. simplex) in both sexes,
the structure of the sternal furca (with
The most distinguishing characteristics
pointed and curved tines in L. simplex), the
of L. marginatus are the possession of: a
morphology of the terminal spines on the
maxillule with simple (instead ofbifid) den-
tiform process (see Figs. 2B and 6A); a 2- exopod of leg 1 (lacking crescent mem-
segmented (instead of3-segmented) exopod brane in L. simplex), and the structure of
of leg 3 with slender setiform element (in- the terminal claw ofmale antenna (bipartite
stead of robust, claw-like spine) on proxi- and equipped with a tridentate medial pro-
mal segment (see Fig. 4A); and a 3-seg- tuberance in L. simplex).
mented exopod of leg 4 with long (instead One hundred and eight species ofcaligid
of minute), proximal, outer spine (see Fig. copepods are currently classified in the ge-
4B). Due to an incomplete original descrip- nus Lepeophtheirus. Among them, six spe-
tion of L. marginatus and the lack of sup- cies were reported from the sea catfishes
plemental information in Causey (1955), (Ariidae). They are L. dissimulatus Wilson,
the first two of these three unusual features 1905; L. monacanthus Heller, 1865; L. un-
ofL. marginatus were unknown until now. ispinosus Pearse, 1952, L. christianensis, L.
Interestingly, these three features are also marginatus and L. orbicularis. Lepeo-
902 PROCEEDINGS OFTHE BIOLOGICAL SOCIETY OF WASHINGTON
Fig. 4. Lepeophtheirus marginatus Bere, 1936. Female. A, leg 3, ventral. B, leg4, anterior. C, terminalpart
ofleg 4 exopod. D, leg 5.
VOLUME 114, NUMBER 4 903
500}jm
Fig. 5. Lepeophtheirus marginatus Bere, 1936. Male. A, habitus, dorsal. B, caudal ramus, dorsal. C, genital
complex and abdomen, ventral.
phtheirus dissimulatus differs from L. mar- 533) stated: "The femaleholotype andmale
ginatus in the structure of leg 3, and L. allotype are U.S.N.M. No. 60548." The
monacanthus and L. unispinosus are distin- type collections kept at Smithsonian Insti-
guishable easily from L. marginatus by the tution show that the catalogue number of
terminal armature on the exopod of leg 1. USNM 60548 is for the type lot ofL. chris-
Thus, only L. christianensis and L. orbicu- tianensis and that of L. marginatus is
USNM
laris remain to be scrutinized further. 69860. Strangely, although L. chris-
In her original report of L. marginatus, tianensis was published eight years later
Bere (1936: 587) stated: "A single male than L. marginatus it is assigned a smaller
and female have been selected for the types (i.e., earlier) catalogue number.
of the new species with U.S.N.M. No. Another curiosity about Wilson's report
60548." Curiously, Wilson (1944) Ustedthe ofL. christianensis concerns the number of
same catalogue number for his type mate- specimens he collected, examined, and de-
rial of L. christianensis. He (Wilson 1944: posited in the National Museum of Natural
904 PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON
Fig. 6. Lepeophtheirus marginatus Bere, 1936. Male. A, antenna (Al), maxillule (A2), and corrugatedpad
(A3), ventral. B, middle and terminal segments ofantenna, anterior. C, sternal furca. D, maxilliped, anterior.
VOLUME 114, NUMBER 4 905
History. Wilson (1944: 533) stated that, and five specimens, respectively. In his
"Thirty specimens, including both sexes, original description of L. orbicularis, Shi-
were obtained from a sea catfish (Galei- ino (1965: 447) stated "No. 577. Ten fe-
chthys sp.) at Pass Christian, Miss.," but males and five males. The largest female is
museum records list a total of32 specimens selected as holotype." But, close examina-
kept in two lots, two (one holotype female tion of each specimen in a drop of lactic
and one allotype male) in a lot carrying the acid disclosed that while specimens in vial
catalogue number of USNM 60548 and 30 1 (containing holotype 9) and vial 2 (con-
ASS)
(18 adult females, nine adult males, one taining 5 $ ? and agree with Shi-
pair in amplexus, and one juvenile female) ino's (1965) description of L. orbicularis,
in another lot identified as USNM 60549. the five specimens (4 9? and IS) kept
Ofthe three distinguishing characteristics in vial 3 are not. They differ from Shiino's
enumerated above for L. marginatus, the original description in the shape of the ab-
segmentation ofthe exopod ofleg 3 and the domen (with straight sides) and structures
armature on its proximal segment are the on leg 3 (with longer velum) and leg 4
most remarkable feature of this species. In (with slender exopod). At this time, those
the original description of L. marginatus, five specimens kept in vial 3 should be ex-
Bere (1936: 588) stated: "The second and cluded from L. orbicularis.
third legs are of the usual type" and thus Shiino's (1965) description of L. orbi-
omitted the illustrations of these two ap- cularis is clear and no supplemental infor-
pendages. On the other hand, in Wilson's mation from our reexamination of the type
(1944: 534) report of L. christianensis, material is significant to this study, except
these two appendages were neither men- for the segmentation of the exopod of leg
tioned nor illustrated. As shown in Fig. 4A, 3, which is clearly 2-segmented as in L.
leg 3 in L. marginatus is not "of the usual marginatus. Although some minor differ-
type." It is rather unusual in bearing a 2- ences were detected in the fine structures of
segmented exopod carrying a setiform ele- the maxillule (length of the dentiform pro-
ment on the proximal segment. These un- cess), maxilla (length of the subterminal
usual features are found in all 32 specimens process and ornamentation on calamus and
ofL. christianensis deposited at the Nation- canna), leg 2 (ornamentation on the two
al Museum of Natural History. A check of outer spines on the terminal segment ofthe
their other features revealed that, indeed, all exopod), and leg 4 (relative length of the
32 specimens are compatible with our re- lateral spine on the proximal segment ofthe
description of L. marginatus. Accordingly, exopod), these differences are considered
we recommend relegating L. christianensis geographical variation, because Shiino's
Wilson, 1944 as a junior synonym of L. (1965) material came from Peru, a different
marginatus Bere, 1936. locality from Bere's (1936). Hence, we rec-
When Shiino (1965) reported L. orbicu- ommend that the name L. orbicularis Shi-
laris, no comments on or comparison with ino, 1960 be relegated as junior synonym
L. marginatus were made. However, after of L. marginatus Bere, 1936.
observing the morphology ofL. marginatus
and noting its close resemblance to L. or- Acknowledgments
bicularis, we felt it was necessary to ex-
amine the type material of the latter, which We thank Chad Walter for arranging the
was kept in the Faculty of Bioresources at loan of type-materials ofL. marginatus and
Mie University in Tsu, Japan. L. christianensis from the collection of the
The type material of L. orbicularis (S- National Museum ofNatural History, Smith-
577) is kept in three vials marked 1, 2, and sonian Institution, and Izawa Kunihiko for
3, with each of them containing one, nine. the visit by one of us (JSH) to Mie Univer-
906 PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON
sity in Tsu, Japan to examine the type-ma- Causey, D. 1955. —Parasitic Copepoda from Gulf of
terial of L. orbicularis at that institution. Z. Mexico fish. Occasional Papers ofthe Marine
Laboratory 9:1-19.
kKnaboawtlaedgaendd ftorwotheoirthceormmreevniteswearnsd asrueggeasc-- Ho, J.pSe.,opGh.thSe.irNuosguseirmap,lex&, Ea.nFeawjesrp-eAcviielsa.of20c0o1p.epLoed-
tions for the improvement ofthis paper. The (Siphonostomatoida: Caligidae) parasitic on
completion of this manuscript was aided by "botete" (bullseye puffer, Sphoeroides annula-
—
a fellowship from the JISTEC (Japan Inter- tus) in Sinaloa, Mexico. Folia Parasitologica
national Science and Technology Exchange (in press).
Center) and a grant from the Paramitas Shiino, S. M. 1965. Parasitic copepods of—the eastern
Pacific fishes. 8. Lepeophtheirus. Report of
Foundation to the senior author (JSH).
Faculty of Fisheries, Prefectural University of
Mie 5(2):441-454.
Literature Cited
Wilson, C. B. 1944. Parasitic copepods in the United
—
Bere, R. 1936. —Parasitic copepods from GulfofMex- States National Museum. Proceedings of the
ico fish. The American Midland Naturalist United States National Museum94(3177):529-
17(3):577-625. 582.