The biology and functional morphology of Macoma biota (Bivalvia: Tellinidae: Macominae)

Pedro Ribeiro Piffer,Flávio Dias Passos,Eliane Pintor De Arruda

doi:10.1590/s1984-46702011000300006

Abstract

Macoma biota Arruda & Domaneschi, 2005, is a recently described species known only from the intertidal zone of Praia da Cidade, Caraguatatuba Bay, in the state of São Paulo, southeastern Brazil. The main purpose of the present paper is to describe the biology of M. biota, beginning with a detailed analysis of its anatomy and functional morphology and how these attributes are correlated with its habitat and life history. The morphology of the organs in the pallial cavity and their sorting devices indicate that this species has efficient mechanisms to process large amounts of particles that enter this cavity via the inhalant current. M. biota can rapidly select the material suitable for ingestion and direct the undesired excess to the rejection mantle tracts. These characteristics along with the siphon's behavior and the digestive tract configuration reveal that this species can be classified primarily as a deposit feeder, like other species of the genus; however, it can also behave as a suspension feeder, depending on the environmental conditions.

Highlights

Macoma biota Arruda & Domaneschi, 2005, is a recently described species known only from the intertidal zone of Praia da Cidade, Caraguatatuba Bay, in the state of São Paulo, southeastern Brazil
The inhalant siphons of M. biota do not possess any barriers that could block the entrance of large amounts of sediment in the pallial cavity
According to YONGE (1949), the ctenidia shape of M. biota, with the complete inner demibranch and incomplete outer demibranch, is an adaptation to deal with large amounts of material that enter the pallial cavity

Summary

Introduction

Macoma biota Arruda & Domaneschi, 2005, is a recently described species known only from the intertidal zone of Praia da Cidade, Caraguatatuba Bay, in the state of São Paulo, southeastern Brazil. M. biota can rapidly select the material suitable for ingestion and direct the undesired excess to the rejection mantle tracts These characteristics along with the siphon’s behavior and the digestive tract configuration reveal that this species can be classified primarily as a deposit feeder, like other species of the genus; it can behave as a suspension feeder, depending on the environmental conditions. The deposit feeders have long and mobile inhalant siphons, which are characteristic of many Tellinidae, whereas the suspension feeders are more phenotypically diverse and culminate in the short and passive siphons present in the Donacidae. Both deposit and suspension feeding individuals can be found in Tellinidae, even within the same species

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