ABSTRACT
Species of the genus Spirobranchus are sessile polychaetes with an important role in marine ecosystems since they are suspension-feeding invertebrates. However, for most species almost nothing is known about their early and larval development, so we describe the early development of two species of Spirobranchus from the Southern Mexican Pacific. The early trochophore larva of S. incrassatus was formed 12 h post-fertilization at 28°C and was described up to a 24-day-old metamorph, whilst it was only possible to follow S. cf. corniculatus to the eight-day-old early trochophore larva. With this study, we describe the early embryological stages, which provide an understanding of the reproductive biology of these polychaetes. Furthermore, this type of information is the basis for future experimental work on the possible response of embryos and larvae to changes in environmental variables, such as temperature.
Acknowledgments
We would like to thank Luisa Rodríguez, Karen Flores, Isa Flores, Walter Alonso and Uriel Cortés for their assistance in the field. Socorro García-Madrigal and Carmen Alejo-Plata (UMAR) revised a first version of this paper that improved the manuscript. Sergio Salazar-Vallejo, Luis F. Carrera-Parra and his wife Wendy, and Itzahí Silva-Morales (ECOSUR) provided critical references. Krista Williams, Jeff Gillon (UMAR) and Miryam Ochoa-Agredano (CICESE) made important suggestions to improve the English. Thanks to two anonymous referees, whose corrections and comments improved this paper.
Disclosure statement
No potential conflict of interest was reported by the author(s).