The glands of the larval foot in Pecten maximus L. and possible homologues in other bivalves

Abstract

A survey by Yonge (1962) of the byssal apparatus in the Bivalvia indicates that the formation of byssus is a larval characteristic which may or may not be retained in the adult. Some species such as the mussel, Mytilus edulis, retain the byssal attachment but have the ability to break the byssus and move over a limited area. Others, such as the scallop, Pecten maximus, lose the byssus entirely, become unattached and move by swimming. Yet others, such as the oyster, Ostrea edulis, relinquish all mobility at metamorphosis by cementing the shell to the substratum, and after metamorphosis lose all trace of the foot. Ostrea, Mytilus and Pecten therefore encompass a wide variety of life styles in the adult and are chosen as examples for detailed comparison of the byssus forming glands and other foot glands in the pediveligers.

Shell morphology changes in the scallop Aequipecten tehuelchus during its life span: a geometric morphometric approach

“…The marked trend towards high auricle asymmetry and the relative elongation of the anterior auricle are explained by their role as a support to prevent overturning of the shell (Stanley 1970). Pectinids show a wide range of life habits, from free swimming to fixed forms, related to the changing attachment capacity throughout ontogeny (see Caddy 1972, Gruffydd et al 1975, Vahl & Clausen 1980, Tang & Pantel 2005. In Aequipecten tehuelchus, byssal attachment gradually disappears with age, but the capacity to form a byssus is not lost in adults (Ciocco et al 1983).…”

“…In pectinids, shifts in life habits throughout ontogeny, mainly related to changes in their swimming behavior and byssal attachment capacity (Caddy 1972, Gruffydd et al 1975, Vahl & Clausen 1980, Tang & Pantel 2005, are concurrent with allometric changes in shell morphology. Scallops characteristically swim with the hinge hindmost, in a direction perpendicular to the hinge axis, and the right valve lies undermost in the swimming and resting or attached positions (Stanley 1970).…”

“…On the other hand, some scallop species cease to form a byssus and live free of attachment on the seabed as juveniles and/or adults. For instance, in Pecten maximus and Placopecten magellanicus, the byssus serves only for temporary attachment and the scallops break free when they grow due to the loss or atrophy of the byssal apparatus (Caddy 1972, Gruffydd et al 1975. Interestingly, even when adults can release the byssus and swim, scallops byssally attached as adults and those that live free on the bottom show morphological differences in their shells (Stanley 1970).…”

Artificial collection and early growth of spat of the scallop <i>Argopecten purpuratus</i> (Lamarck, 1819), in La Rinconada Marine Reserve, Antofagasta, Chile

“…Increasing scallop collection with extended periods of immersion of collectors has also been reported by Román and Cano (1987). In contrast to these results, however, various authors have suggested that for pectinids, including Placopecten magellanicus, P. maximus and P. yessoensis, extended periods of immersion of collectors only results in the biofouling of the collectors, inhibiting larval settlement and interference with the survival of settled scallops (Yamamoto, 1964;Minchin, 1976;Gruffydd and Beaumont, 1972;Gruffydd et al, 1975;Paul, 1978;Naidu and Scaplen, 1979;Brand et al, 1980;Fegan, 1983;Thouzeau, 1989;1991a, b). Fegan (1983), suggested that biofouling of the collectors became effective in inhibiting scallop settlement after 15 days, and Wilson (1987), failed to observe settlement of P. maximus after one month of collector immersion.…”

Anatomia e morfogênese da margem do manto da vieira Nodipecten nodosus (L. 1758) (Bivalvia: Pectinidae)

“…Apart from the detailed study on mantle anatomy of Ostrea edulis larvae carried out by Cranfield (1974), details on larval mantle are fragmentary, and restricted to descriptions on general larval morphology (Raven, 1958;Cragg, 1996). In contrast, the development of other organs and structures, such as gills, foot, velum, and, most of all, shell, has been thoroughly documented for several bivalve representatives (e.g., Ansell, 1962;Gruffydd et al, 1975;Moueza et al, 1999;Carriker, 2001;Weiss et al, 2002;.…”