251. The morphology of the frontal filaments in the nauplii of Verruca stroemia (Müller, 1776) and Hesperibalanus hesperius (Pilsbry, 1916) (Cirripedia: Thoracica)
- Author
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Vladimir V. Malakhov, E. E. Voronezhskaya, and A. L. Obukhova
- Subjects
Protein filament ,biology ,Thoracica ,Anatomy ,Aquatic Science ,Stage ii ,Verruca stroemia ,Oceanography ,biology.organism_classification ,Crustacean - Abstract
Scanning electron microscopy was used to investigate the fine morphology of the frontal filaments (FFs) in nauplial stages of the barnacles Verruca stroemia (Muller, 1776) and Hesperibalanus hesperius (Pilsbry, 1916). Changes in the FF structure in the course of development were examined. The FFs that were revealed in nauplial stage II were retained at all the subsequent nauplial stages. Small openings, which were located either apically or subapically, were found at the top of each FF in both species. In addition, the surface of an FF bears longitudinal grooves. The FFs are not separated from the body; however, each of them has a constriction at the base. In the nauplii of both species, the FFs have a wide proximal and a thin distal part. The area between the proximal and distal parts in V. stroemia has the form of a single crease; in H. hesperius, it resembles an accordion-shaped series of creases. The length ratio of the proximal/distal parts remains constant during all nauplial stages, but it varies between species. The proximal part constitutes 20–25% of the FF length in V. stroemia, while in H. hesperius the proximal and distal parts are approximately equal. The frontal filament length increases proportionally to the length of the larval body in the course of development. The possible functions of FFs as sense organs, their occurrence among the crustaceans, and possible homology with the preantennal limbs are discussed.
- Published
- 2015
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