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|Title:||The smallest carnivorous bivalve? Biology, morphology and behaviour of Grippina coronata (Anomalodesmata: Cuspidarioidea: Spheniopsidae) preying on epipsammic microcrustaceans in the southwestern Atlantic off Brazil|
Machado, Fabrizio Marcondes
Passos, Flavio Dias
|Abstract:||The Spheniopsidae are today represented by five living species of Spheniopsis and nine of Grippina, distributed in the Pacific and Atlantic Oceans. Little is known of their anatomy and the phylogenetic position of the family within the Bivalvia is debated. In order to investigate these questions, the functional morphology of Grippina coronata obtained from the continental shelf off Rio de Janeiro and Espirito Santo States, Brazil, has been examined. Less than 2 mm in shell length, the siphonal apparatus of G. coronata is complex, with seven sensory papillae, and the ctenidia are reduced to transverse septa pierced by four pairs of ciliated pores. There are no labial palps and the stomach is of Type II with epibenthic harpacticoid and ostracod prey identified inside it. Although there is an intestine producing faeces, the stomach also possesses a unique waste storage pouch for exoskeletal remains of digested prey. Collectively, these features suggest that the Spheniopsidae comprise carnivorous taxa belonging to the Cuspidarioidea within the Anomalodesmata. Grippina coronata is a self-fertilizing simultaneous hermaphrodite that, uniquely, broods fertilized oocytes within the ovarian follicles and, thereby, provides the first example of intrafollicular fertilization and brooding in the Bivalvia. Release of the encapsulated oocytes must be by parental death, which coincidentally releases the exoskeletal remains from the storage pouch. Such post mortem semelparity creates a life-history trait hitherto unrecognized in the Bivalvia|
|Editor:||Oxford University Press|
|Appears in Collections:||IB - Artigos e Outros Documentos|
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