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ebriids, Ebriidae

Chitchai Chantangsi and Brian S. Leander
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taxon links extinct icon extinct icon extinct icon extinct icon extinct icon extinct icon extinct icon extinct icon extinct icon extinct icon extinct icon extinct icon extinct icon extinct icon extinct icon extinct icon extinct icon extinct icon extinct icon extinct icon extinct icon extinct icon extinct icon extinct icon [down<--]Thecofilosea Interpreting the tree
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Tree based on paleontological record of ebriid internal skeletons: references.
Containing group: Thecofilosea


The Ebriida or Ebriidae is a small group of marine predatory biflagellates that inhabit planktonic communities in temperate and tropical zones, especially in coastal areas. The group has a rich fossil record and currently contains only two extant genera, Ebria and Hermesinum (see title illustration), comprising three extant species -- E. tripartita, and H. adriaticum and perhaps H. platense (Hargraves, 2002; Patterson et al., 2002; Tiffany, 2002). However, ebriids are best known for their extensive fossil record that dates back to the Cenozoic Era (Korhola and Grönlund, 1999; Taylor, 1990). The name of this group means “drunken” due to their spiralling swimming behavior (Taylor, 1990). Cell dimensions vary from 25-55 μm (Hoppenrath and Leander, 2006b; Throndsen, 1997; Tiffany, 2002). Ebriids are heterotrophic, mixotrophic, bacterivorous, and algivorous (Hargraves, 2002; Hoppenrath and Leander, 2006b; Patterson et al., 2002); most cells are found feeding on filamentous diatoms (Hargraves and Miller, 1974; Taylor, 1990) and dinoflagellates (Patterson et al., 2002; Taylor, 1990; Tappan, 1980).


Ebriids are characterized by the following features:

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Figure 1. Light micrograph of Ebria tripartita (Thecofilosea) showing the internal, branching, solid, siliceous skeleton (© 2001 David J. Patterson).


Ebriids' habitats are cold to warm marine or brackish environments (Taylor, 1990; Throndsen, 1997). Ebria tends to live in colder habitats and a wide range of salinities, while Hermesinum prefers warmer environments and a narrower range of salinities (>20oC and 15-30 ppt salinity) (Patterson et al., 2002; Rhodes and Gibson, 1981; Taylor, 1990; Throndsen, 1997).


Reproduction of ebriids has been poorly studied. Only asexual reproduction is known (Tappan, 1980; Taylor, 1990). Formation of the skeletons during division is thought to begin before nuclear division, and daughter cell segregation happens before completion of siliceous skeletal formation (Taylor, 1990; Tiffany, 2002).

Discussion of Phylogenetic Relationships

Phylogenetic analyses based on nuclear small subunit (SSU) rRNA genes demonstrated that Ebria tripartita is a member of the Cercozoa and is a sister taxon to cryomonads (Hoppenrath and Leander, 2006b). This inference is supported by ultrastructural data, including the possession of two unequal flagella and a nucleus with a prominent nucleolus and permanently condensed chromosomes (Hoppenrath and Leander, 2006a,b; Schnepf and Kühn, 2000; Thomsen et al., 1991).

Other Names for Ebriida


Hargraves, P. E. 2002. The ebridian flagellates Ebria and Hermesinum. Plankton Biol. Ecol. 49: 9-16.

Hargraves, P. and Miller, B. 1974. The ebridian flagellate Hermesinum adriaticum Zach. Arch. Protist. 116: 280-284.

Hoppenrath, M. and Leander, B. S. 2006a. Dinoflagellate, euglenid or cercomonad? The ultrastructure and molecular phylogenetic position of Protaspis grandis n. sp. J. Eukaryot. Microbiol. 53: 327-342.

Hoppenrath, M. and Leander, B. S. 2006b. Ebriid phylogeny and the expansion of the Cercozoa. Protist 157: 279-290.

Korhola, A. and Grönlund, T. 1999. Observations of Ebria tripartita (Schumann) Lemmermann in Baltic sediments. J. Paleolimnol. 21: 1-8.

Patterson, D. J., Vørs, N., Simpson, A. G. B. and O’ Kelly, C. 2002. Residual free-living and predatory heterotrophic flagellates. In: Lee, J. J., Leedale, G. F., and Bradbury, P. (Eds.), An illustrated guide to the protozoa, (2nd ed., Vol. 2, pp. 1302-1328). Society of Protozoologists. Lawrence, KS: Allen Press.

Rhodes, R. G. and Gibson, V. R. 1981. An annual survey of Hermesinum adriaticum and Ebria tripartita, two ebridian algae in the Lower Chesapeake Bay. Estuaries 4: 150-152.

Schnepf, E. and Kühn, S. F. 2000. Food uptake and fine structure of Cryothecomonas longipes sp. nov., a marine nanoflagellate incertae sedis feeding phagotrophically on large diatoms. Helgol. Mar. Res. 54: 18-32.

Tappan, H. N. 1980. The paleobiology of plant protists. San Francisco: W. H. Freeman & Co.

Taylor, F. J. R. 1990. Incertae sedis Ebridians. In: Margulis, L., Corliss, J. O., Melkonian, M., and Chapman, D. J. (Eds.), Handbook of Protoctista, (pp 720-721). Boston: Jones and Bartlett Publishers.

Thomsen, H. A., Buck, K. R., Bolt, P. A., and Garrison, D. L. 1991. Fine structure and biology of Cryothecomonas gen. nov. (Protista incertae sedis) from the ice biota. Can. J. Zool. 69: 1048-1070.

Throndsen, J. 1997. The planktonic marine flagellates. In: Tomas, C. R. (Ed.), Identifying Marine Phytoplankton, (2nd ed., pp. 591-729). New York: Academic Press.

Tiffany, M. A. 2002. Skeletal development in Hermesinum adriaticum Zacharias, a flagellate from the Salton Sea, California. Hydrobiologia 473: 217-221.

Title Illustrations
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Scientific Name (a) Ebria tripartita and (b) Hermesinum adriaticum.
Acknowledgements Modified from Taylor, 1990.
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About This Page

This page is being developed as part of the Tree of Life Web Project Protist Diversity Workshop, co-sponsored by the Canadian Institute for Advanced Research (CIFAR) program in Integrated Microbial Biodiversity and the Tula Foundation.

The University of British Columbia, Vancouver, Canada

Brian S. Leander
The University of British Columbia, Vancouver, British Columbia, Canada

Correspondence regarding this page should be directed to Chitchai Chantangsi at and Brian S. Leander at

Page: Tree of Life Ebriida. ebriids, Ebriidae. Authored by Chitchai Chantangsi and Brian S. Leander. The TEXT of this page is licensed under the Creative Commons Attribution-NonCommercial License - Version 3.0. Note that images and other media featured on this page are each governed by their own license, and they may or may not be available for reuse. Click on an image or a media link to access the media data window, which provides the relevant licensing information. For the general terms and conditions of ToL material reuse and redistribution, please see the Tree of Life Copyright Policies.

Citing this page:

Chantangsi, Chitchai and Brian S. Leander. 2010. Ebriida. ebriids, Ebriidae. Version 17 January 2010 (under construction). http://tolweb.org/Ebriida/2401/2010.01.17 in The Tree of Life Web Project, http://tolweb.org/

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