Gonadal development, allometric growth and ecological impact of Appendicularia sicula (Appendicularia: Fritillaridae) from the south-western Atlantic Ocean

AGUIRRE, G.; CAPITANIO, F.; VIÑAS, M.; ESNAL, G.

JOURNAL OF THE MARINE BIOLOGICAL ASSOCIATION OF THE UNITED KINGDOM

Cambridge University Press

Lugar: Plymonth, UK; Año: 2006 vol. 86 p. 1215 - 1220

0025-3154

The gonadal development and morphometry of Appendicularia sicula (Appendicularia: Fritillariidae) were studied by means of histological sections and from the measurement of several characters. Based on morphometric measurements, the ingestion and clearance rates and the percentages of consumed chlorophyll were also estimated. The gonadal development is similar to that of Fritillaria pellucida. A small dorsal ovotestis, which originates ovary and testicle, shows large somatic nuclei inside. In the ovary these somatic nuclei are surrounded by a single layer of germ cells nuclei, whereas in the testicle they are found between the small nuclei of the germ cells. As the development proceeds, the large somatic nuclei are resorbed in both gonads, and the testicle envelopes the ovary posteriorly. After spermatozoids emission, the rectum is shown occupying most of the body volume. The length of the rectum shows positive allometric growth in respect to the length of the trunk, which can be ascribed to its continuous accumulation of matter due to the lack of an anus. In the ovary these somatic nuclei are surrounded by a single layer of germ cells nuclei, whereas in the testicle they are found between the small nuclei of the germ cells. were studied by means of histological sections and from the measurement of several characters. Based on morphometric measurements, the ingestion and clearance rates and the percentages of consumed chlorophyll were also estimated. The gonadal development is similar to that of Fritillaria pellucida. The length of the rectum shows a positive allometric growth in respect to the length of the trunk, which can be ascribed to its continuous accumulation of matter due to the lack of an anus. The relationship obtained between trunk length were studied by means of histological sections and from the measurement of several characters. Based on morphometric measurements, the ingestion and clearance rates and the percentages of consumed chlorophyll were also estimated.