Experiences of a Non-Governmental Organisation (NGO) dedicated to the conservation of Arctic char <Emphasis Type="Italic">Salvelinus alpinus</Emphasis> in Ireland |
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Authors: | Fran Igoe Stephen Neylon Myles Kelly |
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Institution: | 1.Irish Char Conservation Group,Kimmage, Dublin 12,Ireland |
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Abstract: | Podocopid ostracods have a calcified carapace encasing their uncalcified body parts like an envelope. A marginal infold (calcified
inner lamella) develops along the free margin of both valves, notably in the adult stage. Radial pore canals, which often
exhibit a distinct branched shape, can be seen in the free margin and they connect to the space between the outer and inner
calcified cuticles called “vestibule.” These characters associated with the marginal infold have been recognized as important
criteria both taxonomically and anatomically, but the calcification process of the marginal infold has never been investigated.
In this study, we observed the calcification process of the anterior free margin in Leptocythere species. The free margin of the adult specimen starts its calcification just after ecdysis, but the degree of calcification
remains the same as in the juvenile until approximately 35 h after ecdysis. The marginal infold of the adult specimen then
begins to calcify from its distal part around 40 h postecdysis, and short simple pore canals can still be observed in the
free margin. Marginal pore canals become more branched and narrower as calcification proceeds beyond 100 h postecdysis. These
results indicate that the calcification of the free margin in a podocopid carapace occurs in two steps, and needs much time
to complete the process even in small species of Leptocythere. In addition, these observations provide a basis for discussion on the correlation of the carapace size, environmental factors
of the habitat, and the development of the vestibule in some Krithe species, “Krithe problem.” |
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