- Complete, identified, developmental series of larval cottids
Artedius fenestralis, A. creaseri, A. meanyi, Oligocottus snyderi,
Clinocottus embryum, and C. globiceps are described for the first
time. In addition, redescriptions of four species, Artedius harringtoni,
A. lateralis, Oligocottus maculosus, and Clinocottus acuticeps
are included that provide new and comparative information on larval
development. Partial developmental series of two species, Artedius
Type 3 and Clinocottus analis, are also described and illustrated for
the first time.
Using the methods of phylogenetic analysis proposed by Hennig
(1966), characters of the larvae of 13 species of Artedius, Clinocottus,
and Oligocottus are examined in terms of synapomorphic states.
Number and pattern of preopercular spines, gut diverticula, body
shape, and a bubble of skin at the nape are identified as synapomorphic
characters useful in systematic analysis of this group.
The synapomorphic character, multiple preopercular spines, provides
strong evidence that Clinocottus acuticeps, C. analis, C. embryum,
C. globiceps, C. recalvus, Oligocottus maculosus, 0. snyderi, Artedius
fenestralis, A. harringtoni, A. lateralis, and A. Type 3 form a
monophyletic group within the Cottidae. Within this group, the species
of Clinocottus and Oligocottus are very closely related; however, each
genus appears to be monophyletic. Larvae of all species of Clinocottus
possess the synapomorphy, auxiliary preopercular spines. Larval Oligocottus
maculosus and 0. snyderi share two derived characters, dorsal
gut bumps and a bubble of skin at the nape. Artedius fenestralis, A.
harringtoni, A. lateralis, and A. Type also form a monophyletic group
closely related to Clinocottus and Oligocottus on the basis of a
unique multiple preopercular spine pattern.
Synapomorphic characters of the larvae provide strong evidence
that A. creaseri and A. meanyi are more closely related to Icelinus
than to species of Clinocottus, Oligocottus maculosus, O. snyderi,
Artedius fenestralis, A. harringtoni, A. lateralis, and A. Type 3.
Characters of the larvae strongly indicate that the genus Artedius as
defined by Bolin (1934, 1947) is not monophyletic and that A. creaseri
and A. meanyi should be placed separately from the other species of
Artedius. Clarification of the exact position of these two species
in relation to Icelinus and the Artedius-Clinocottus-Oligocottus group
must await identification of larvae of all species of Icelinus and
reexamination of characters of adult Icelinus and Artedius.