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A new species of the flatfish genus Chascanopsetta (Pleuronectiformes: Bothidae), from the coasts of Kenya and Komalia with comments on C. lugubris
Dannie A. Hensley and Malcolm J. Smale
Abstract
Six species of the genus Chascanopsetta are currently recognized. Recent
work on otolith morphology from specimens identified as C. lugubris raised
the possibility that three forms of C. lugubris are found in the western
Indian Ocean. Re-examination of the voucher specimens showed that one of
these forms is a new species, C. kenyaensis, from Kenya and Somalia. The
other two forms may show differences in otolith morphology due to ontogeny.
The new species most closely resembles C. prorigera from the Hawaiian
Archipelago, Emperor Seamounts, and the western North Atlantic. These two
species differ in lateral-line scale counts, body depth, upper-jaw length,
and coloration. Many comparative specimens of C. lugubris were examined. It
was found that this species' distribution rounds the Cape of Good Hope from
the southwestern Indian Ocean into the southeastern Atlantic. Specimens
from this southern African region show higher dorsal- and anal- fin ray
counts than those from more northern areas in the Atlantic, western
Pacific, and Indian oceans. There is some indication that what some authors
refer to as the Indo-West Pacific subspecies C. lugubris lugubris rounds
the Cape of Good Hope and also occurs in pans of the eastern Atlantic. A
more thorough comparison of C. lugubris from different regions is needed.
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