Concerning Intraspecific Taxa in Fritillaria Borealis Lohmann (Tunicata, Appendicularia)

Presently only three intraspecific formae are recognized in Fritillaria borealis Lohmann, 1896: typica, intermedia and sargassi, but the characterization of intermedia is imprecise. We re-examine the problem of intraspecific variability in this species on the basis of a morphological study on specimens collected in an extensive area (between 78°29′S and 9°34′N, and between 117°01′E and 36°00′W). Clearly the relative position of the ovary and testis is a distinctive characteristic that separates two groups: A—with a symmetrical arrangement of the gonads and B—with an asymmetrical arrangement of the gonads. The variations observed in each of these groups can be ascribed to different growth and maturation stages of the gonads. The possibility of considering these groups as intraspecific taxa is discussed and we suggest that a better choice is to treat them as separate species as classified by Lohmann (1896) with F. borealis occurring from pole to pole and F. sargassi inhabiting warm and cool waters.