Parasitic Copepods of Mackerel - and Tuna-like Fishes (Scombridae ...

24 SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY
same host species, reported as E. allitteratus [sic]
from north Queensland, Australia.
FEMALE.—Body form as in Figure 41c. Total length
4.62 mm (4.27-4.73 mm) based on an average of 5
specimens. Greatest width 2.1 mm (measured at
widest part of cephalon). Cephalon comprises about
one-half total body length. Genital segment somewhat
longer than wide (1.77 X 1.55 mm), posterior corners
produced to form rounded lobes. Abdomen 2-segmented,
segments measure 1.02 and 0.43 mm long
respectively, comprising about one-third total body
length. Caudal rami as in Caligus coryphaenae except
outer terminal seta much stouter in C. regalis.
Frontal lunules widely spaced, each about 400 /*m
wide, rostral space between each lunule about 950 /xrn.
Cephalic appendages as in C. coryphaenae except
sternal furca not as divergent in C. regalis (Figure
Legs 1-4 as in C. coryphaenae; the stout spine on
the first exopod segment of leg 3 (Figure 41«) is
curved inwards rather than straight as in C. coryphaenae.
The apical seta on the exopod of leg 4
(Figure 41/) is only slightly longer than the adjacent
seta, setae measure 189, 177, 177, 177, and 183 /*m
distal to proximal respectively.
MALE.—Body form as C. coryphaenae. Total length
3.51 mm (3.37-3.53 mm) based on an average of 5
specimens. Greatest width 1.73 mm (measured at
widest part of cephalon). Genital segment (Figure
41g) wider than long (914 X 711 /un). Caudal rami
with outermost terminal seta stout and about as wide
at base as other 3 (much smaller in C. coryphaenae).
Legs 5 and 6 at posterior outer corners. Abdomen 2segmented,
segments measure 247 and 479 /tin respectively.
REMARKS.—Pillai, 1962b, discussed the relationship
between this species and C. coryphaenae and provided
a comprehensive description of C. regalis (as C.
euthynus). All collection records to date indicate that
C. regalis is specific to Euthynnus affinis and C.
coryphaenae is primarily found on other species of
scombrids of the tribe Thunnini.
These 2 species of Caligus differ from other members
of the genus in lacking a postantennal process
(Lewis 1967:105, considered the group of sensillae
at the usual site of the postantennal process as representing
the process). When the genus Caligus has
undergone a much needed revision it may be that
these 2 species should be removed from the genus.
We have placed Heegaard's C. alveolaris and
Kurian's C. euthynus in synonymy with C. regalis of
Leigh-Sharpe. Although Leigh-Sharpe's figures are
poor there is little doubt that they illustrate the copepods
discussed here, especially considering that he
collected his material from the same host-species (as
E. yaito).
Caligus productus Dana, 1852
FIGURES 42-44, 103
Caligus productus Dana, 1852:56.
Caligus alalongae Kroyer, 1863:129.
Caligus monacanthi Kroyer, 1863:133.
Caligus lobatus Wilson, 1935:1.
Caligus katuwo Yamaguti, 1936:6.
Caligus dentatus Heegaard, 1962:160.
Caligus microdontus Heegaard, 1964:139.
This species has been recorded many times from
scombrids and occasionally non-scombrid hosts (see
Lewis, 1967:116). Shiino, 1959b and Lewis, 1967
have provided good descriptions and we do not feel
a need to repeat another here. We have, however,
provided pertinent illustrations and a consideration
of certain characters to enable the reader to identify
this species without resorting to other literature. A
complete synopsis of the literature has been provided
by Margolis, Kabata, and Parker (1975:64).
MATERIAL EXAMINED.—207 collections containing
2286 9 , 657