BRACHIOPODA

From Eldredge (1991)


INTRODUCTION

The brachiopods are a large group of solitary and exclusively marine organisms with a very good geologic history throughout most of the Phanerozoic and are among the most successful benthic macroinvertebrates of the Paleozoic. They are typified by two mineralized valves which enclose most of the animal. Like the bryozoans, brachiopods are filter feeders which collect food particles on a ciliated organ called the lophophore. An excellent example of a brachiopod lophophore can be seen in the Recent terebratulid. Brachiopods differ in many ways from bryozoans (in both soft and hard-part morphology), and are thus considered by most workers as a separate but closely related phylum. However, one of the most distinguishing features of brachiopods is the presence of a pedicle, a fleshy stalk-like structure that aids the animal in burrowing and maintaining stability. The pedicle can be seen in the Recent Lingula.

Currently, brachiopods are divided into two or three major groups. We depart from your text in considering two major groups: Class Inarticulata (including lingulids), and Class Articulata based on the presence or absence of hinge teeth and sockets.

A large portion of this lab is designed to make you familiar with the seemingly endless morphologic terms associated with brachiopods. This is a necessary process, as understanding such features are the only tools available to enable one to identify brachiopods with any success Although it may seem unreasonable to ask one to learn the various groups presented below, with a little common sense and observational skills, recognition is actually easier then it may first seem.


CLASSIFICATION & GEOLOGIC RANGES

Phylum Brachiopoda (Cambrian-Recent)

Class Inarticulata (Cambrian-Recent)

Class Articulata (Cambrian-Recent)

Order Orthida (Cambrian-Permian)

Order Strophomenida (Ordovician-Jurassic)

Order Pentamerida (Cambrian-Devonian)

Order Rhynchonellida (Ordovician-Recent)

Order Spiriferida (Ordovician-Jurassic)

Order Terebratulida (Devonian-Recent)

 


Continue on to

MORPHOLOGY AND ECOLOGY

CLASSIFICATION


Return to
Topic List