Early development of two Capitella species (Annelida: Capitellidae) from the Gulf of Mexico.

Early development of the polychaetes Capitella sp. TF from Tampa, Florida and Capitella sp. TV from Tamiahua Lagoon, Veracruz was studied under laboratory conditions. Our observations indicate that hermaphrodites occur in Capitella sp. TF, but not in Capitella sp. TV. Length and volume of larvae and early juveniles were measured daily. Both species appear to have lecithotrophic development. Sizes and duration of the developmental stages varied widely, as in most known species of Capitella. Characteristic features of Capitella sp. TF include very small hermaphrodites with a distinct dorsal pigmentation pattern and characteristically shaped brood tubes with a centrally thickened region. Embryos forced to abandon the brood did not survive more than 3 days, and handling the brood produced alterations in timing. Ciliated metatrochophores from Capitella sp. TV survived inside the brood without the female for at least 14 days and some larvae hatched and died during settling. Some of these larvae were abnormal, with two rounded protuberances in the two ends. Mortality was high. Fungi and protozoans appeared in the dishes and probably partially induced the production of thicker mucus in the brood tubes, delay in metamorphosis, juvenile mortality, worm length and failure in coupling. Size and duration of the developmental stages were distinctly different from the other putative lecithotrophic species of the complex. These differences and other characteristics of each species discard the possibility that they belong to a previously described species. Our results are applicable to future ecological, morphological and molecular studies of each species, habitat and phylogenetics. [ABSTRACT FROM AUTHOR]