ABSTRACT
RELATIONSHIPS OF EUKARYOTIC ALGAL GROUPS TO OTHER PROTISTS
Charles J. O'Kelly
TABLE OF CONTENTS
I. Introduction 270
II. Protist Diversity and Eukaryotic Algal Origins 270
III. The Euglenoid-Kinetoplastid Clade 272
IV. The Stramenopiles 274
V. Erstwhile Stramenopiles: Prymnesiophytes and
Cryptomonads 279
VI. Dinoflagellates 280
VII. Green Algae, Red Algae, Glaucophytes: Monophyletic or Polyphyletic? 282
VIII. Chlorarachniophytes 284 IX. Grades, Clades, and Codes: The Problem of Algal
Nomenclature 284
Acknowledgments 287
References 288
O-8493-6323-3/93/$O.0O + $.5O C 1993 by CRC Press, Inc. 269
It is easy to define "algae" on the basis of what they lack. They lack embryos, or at least ones that have developmental sequences identical with those of multicellular animals or embryophytic plants; they lack sterile jackets around sex cells that have the precise structure and development of archegonia and antheridia.13 However, it is impossible to define "algae" on the basis of what they have. As has been known for some time,4 this assemblage of organisms that seems alike in terms of their superficial structure, physiology, and ecology is in fact a motley assortment of representatives from many different family trees. In more formal terms, no set of shared derived characters differentiates all algae from other forms of life. Moreover, there is ample evidence that different algal lineages arose from separate and phylogenetically distinct ancestors; the group called algae is polyphyletic.
