Robert Jan "Roy" van de Hoek, President
Ballona Institute
Los Angeles, California
roy@naturespeace.org
June 17, 2014

EXCERPTS FROM EVOLUTION OF TELLINACEA (BIVALVIA)


FOREWORD
          Ross Pohlo began his academic field research into ecology and evolultion of pelecypods (clams) at Tomales Bay, in 1960 about 54 years ago for his PhD research. His studies of pelecypods continued for the next 22 years culminating with an article in 1982, which I have excerpted the abstract that is presented here. Approximately 30 years has lapsed since Ross Pohlo wrote this fine article, so naturally there have been nomenclatural name changes to some orders and super families. Some of these changes include:

Heterodonts have been elevated from an order to subclass Heterodonta.

The super family Astartacea is now Crassatelloidea. The super family Tellinacea is now Tellinoidea, and Carditacea is unchanged, while both are together in the order Veneroida.

The families Tellinidae, Semelidae, Donacidae, Solecurtidae, Psammobiidae, are valid names in the order Veneroida, while Scrobiculariidae was synonomized into Semelidae.

Sanguinolaria, now Nuttallia, remains in the family Psammobiidae, while Tagelus is in the family Solecurtidae.


EVOLUTION OF TELLINACEA (BIVALVIA)
Journal of Molluscan Studies Volume 48 (3): 245-256
Ross H. Pohlo Department of Biology,
California State University, Northridge 91324
ABSTRACT
          The suspension feeding Astartacea appear to be among the earliest heterodonts. These organisms may have given rise to the Carditacea and the rest of the heterodonts including the Tellinacea.
          Paleontological evidence indicates that the earliest Tellinacea were suspension feeders with members that lived vertically in a burrow of sifting sand. These conditions resemble those found in species of modern Donax in the Donacidae. From a Donax-like state of suspension feeding evolution most likely proceeded to non-selective feeders. Extant organisms that resemble this are found in the Solecurtidae. A later stage resembles some of the extant Psammobiidae. The final stage in tellinaceaen evolution is the acquisition of deposit feeding with its associated morphology. These stages are observed in the Scrobiculariidae, Tellinidae and a few members of the Semelidae.
INTRODUCTION
          I have previously outlined broad features of evolution within the Tellinacea (Pohlo, 1967).