Taxonomic position of and generic distinction between Parepactophanes Kunz, 1935 and Taurocletodes Kunz, 1975 (Copepoda, Canthocamptidae incertae sedis), with description of a new species from the Black Sea
Author
Karaytuǧ, Süphan
Author
Huys, Rony
text
Zoological Journal of the Linnean Society
2004
2004-04-30
140
4
469
486
https://academic.oup.com/zoolinnean/article-lookup/doi/10.1111/j.1096-3642.2003.00101.x
journal article
3958
10.1111/j.1096-3642.2003.00101.x
18c536db-6020-42c6-ba39-48be66b42f3d
0024-4082
4634523
VALIDITY OF
TAUROCLETODES
AND GENERIC DIAGNOSES
Proper comparison between the
type
species
P. minuta
and the material variously identified or named as
P.
?
dubia
,
T. gallicus
or
P. dubia
has until now been hampered by the fragmentary nature of the corresponding (re)descriptions or the unavailability of either males (
Noodt, 1958b
) or females (
Kunz, 1975
). Consequently, the issue whether the respective
type
species of
Parepactophanes
and
Taurocletodes
are congeneric (
Kunz, 1983
), has not been satisfactorily addressed. The description of both sexes of
T. tumenae
now enables us to subject the proposed synonymy of
Parepactophanes
and
Taurocletodes
to more scrutiny. Although
Noodt (1958b)
identified
Parepactophanes
as the closest match for
P.
?
dubia
, it is obvious that he intended only provisional generic assignment. Amongst other, less significant, features he recognized the 3-segmented P1 endopod in the Tenerife material as the major stumbling block to its inclusion in
Parepactophanes
, since both the
type
species
P. minuta
and the allegedly most closely related genera (
Cletocamptus
,
Limnocletodes
Borutzky
) exhibit the 2-segmented condition.
Parepactophanes minuta
has not been redescribed since Kunz’ (1935) original description, which omitted illustrations of the mouthparts but was otherwise sufficiently informative by contemporary standards. Using Kunz’ (1935) illustrations as the basis for comparison with
T. tumenae
we believe that there are sufficient grounds to maintain the generic distinction between
Parepactophanes
and
Taurocletodes
. Most diagnostic characters readily emerge from a comparison of the swimming legs. We have no reason to doubt the accuracy of Kunz’ observations of the swimming legs since Noodt, who was generally more detailed in his approach and identified
P. minuta
on more than one occasion (
Noodt, 1956
,
1957
,
1958a
), would undoubtedly have reported oversights or ambiguities in the original description when attempting to overcome the difficulties in placing
P.
?
dubia
.
The P1 endopod in
Parepactophanes
is as long as the exopod, 2-segmented, displays a [1.111] armature formula and lacks penicillate setae on the distal segment. In
Taurocletodes
it is distinctly longer than the exopod, 3-segmented, exhibiting a formula [1.1.111] with the inner seta on the middle and distal segments clearly penicillate in nature (
Figs 5A,B
,
9A
) (for absence of these setae in Kunz’ (1975) description of
T. gallicus
, see below). The distal exopod segment of P2–P4 has two outer spines in
Taurocletodes
but this number is reduced to one in
Parepactophanes
. In addition,
P. minuta
possesses an inner seta on P4 exp-3, which is lacking in all
Taurocletodes
species. Males of both genera can be readily distinguished by the sexual dimorphism on the P2–P3 exopods, being completely absent in
Parepactophanes
, but clearly expressed in the outer spine of the proximal segment in
Taurocletodes
. This modification is moderate in P2, involving modest size increase of the spine and loss of surface ornamentation (
Fig. 5C, D
). It attains extreme proportions on the proximal exopod segment of P3 where the massive spine arises from a distinct pedestal, formed by the outer portion of the segment, and reaches to halfway along the distal segment (
Fig. 6B,C
).
Both genera also differ in the segmentation and sexual dimorphism of the P2–P3 endopods. In
P. minuta
the endopods are 1-segmented and that of the P2 not sexually dimorphic. In
Taurocletodes
both endopods are 2-segmented but the inner seta on enp-1 found in the female P2 (and corresponding to the inner seta of the 1-segmented endopod of
Parepactophanes
) is absent in males. The sexual dimorphism of the P3 endopod is similar in both genera although the fine details of segmentation and ornamentation are not discernible in Kunz’ drawings of
P. minuta
. The distal portion of the male P3 endopod appears to extend into an apophysis and the inner seta present in the female is lost in the male (as in
Taurocletodes
;
Fig. 6B,D
).
Finally, in
Parepactophanes
the rostrum is short and blunt, and the female P5 baseoendopod bears two spines and two setae. In
Taurocletodes
, the rostrum is long and spatulate (
Figs 3A
,
4A
) and the endopodal lobe of the female P5 carries four setiform elements (
Fig. 5E
).
On the basis of the suite of generic diagnostics identified above we refute Kunz’ (1983) course of action to relegate
Taurocletodes
to a junior synonym of
Parepactophanes
, and instead re-instate the former as a valid genus, with
T. dubius
(Noodt, 1958)
comb. nov.
as its
type
species. Amended generic diagnoses for both genera are given below.