Embryonic
and larval staging of summer flounder (Paralichthys dentatus)
G.M.
Martinez, J.A. Bolker-2003
Journal
of Morphology, 255(2): 162-176 (from
ISI Current Contents)
Abstract:
Early development of flatfishes such as the summer flounder Paralichthys
dentatus (Pleuronectiformes) has not been extensively documented, largely
because of a dearth of material; however, the recent expansion of flatfish
aquaculture has made embryos of P. dentatus readily available for
developmental studies. We divide development of P. dentatus embryos and
larvae into two main periods, pre- and posthatching, and assign stages
within each of those primary divisions. Stages from fertilization to
hatching loosely follow the general teleost staging scheme suggested by
Shardo ([1995] J Morphol 225:125-167); stages from hatching through
metamorphosis are aligned with the series used for Japanese flounder, P.
olivaceus (Minami [1982] Nippon Suisan Gakkaishi 48:1581-1588; Fukuhara
[1986] Nippon Suisan Gakkaishi 52:81-91). Although length, width, and age
may serve as approximate indicators of developmental progression in summer
flounder, these characteristics are too variable to form the sole basis of a
staging table. Therefore, we define stages by morphological criteria drawn
from the development of the jaw apparatus and digestive system, eye
migration, and notochord tip flexion. Examination of these morphological
features in hatched larvae allows accurate and consistent assessment of
developmental stage despite variation in timing and size. The staging scheme
for flounder embryonic and larval development presented here should
facilitate both experimental and comparative research on summer flounder and
other flatfish species.
(Univ.
New Hampshire, Dept. Zoology, Rudman Hall, 46 Coll Rd., Durham NH 03824,
USA, e-mail: gabriela@cisunix.unh.edu)