Alexandrium tamarense

Classification

Domain: Eukarya
    Kingdom: Dinoflagellata
        Phylum: Dinophyta
            Class: Dinophyceae
                Order: Gonyaulacales
                    Family: Goniodomataceae
                        Genus: Alexandrium
                    Species: Alexandrium tamarense

Domain: Eukarya

The Eukarya domain includes a wide variety of organisms such as protists, animals, plants, and fungi. Alexandrium tamarense belongs to this domain because it possesses membrane bound organelles, a plasma membrane, and contains a true nucleus.

Kingdom: Dinoflagellata

This kingdom contains organisms that vary from being parasitic to mutualistic. Organisms that belong to this kingdom tend to exhibit these general characteristics: two flagella (used for locomotion or acquisition of food particles), unicellular, contain cellulose plates under their membrane, and are primary producers in marine environments.

Phylum: Dinophyta

This phylum consists predominantly of “flagellate unicellular marine organisms, often dark brown in colour due to the presence of the xanthophyll pigment peridinin”(Dictionary of Botany. 2003). This phylum can be divided into two classes, the Desmophyceae and the Dinophyceae.

Class: Dinophyceae

This class is specified to have organisms that exhibit a motile stage in their life in which they have two rear dissimilar flagella. They use these flagella for locomotion and in some cases to acquire food.

Order: Gonyaulacales

This order includes “cells with a series of cellulose plates organized in a regular pattern” (Balech, 1995). At this stage of evolution the development of the cellulose plates under the membrane form distinct patterns. This can help separate different species from one another.

Family: Gonyaulacaceae

In this family a sulcus is formed on the organism and is more or less midventral (Bio*Pedia, 2008). A sulcus is a groove that forms on the organism. The formation of this groove helps us be able to see all of the cellulose plates under the membrane of the organism.

Genus: Alexandrium

Alexandrium is genus that contains the largest number of toxic species in the Dinoflagellates. There are a total of thirty four species among the fourteen genera that are considered toxin producers (Taylor, 1985). Alexandrium is considered to include almost all the species that contribute to Paralytic Shellfish Poisoning and Red Tide.

Species: Alexandrium tamarense

This species of Alexandrium is often confused with other species within its genus but because of the size and shape of Alexandrium tamarense it is distinguishable. This species is a microscopic organism, the size and shape of Alexandrium tamarense is highly variable: cells range in size between 22-51 µm in length and 17-44 µm. As you can see Alexandrium tamarense is a tiny organism but its affects on marine environments is huge! To learn more about its affects head on over to Interactions!

Phylogenetic Trees!

Phylogenetic Tree. Modified from Campbell et. al.
Lindsay Hoessel 2013

The tree above shows how the Dinoflagellates fit into the whole scheme of classifications between all organisms. It shows that the Dinoflagellates are closely related to the Apicomplexans and the Ciliates but even further it shows that the Dinoflagellates and Apicomplexans are more alike to each other than they are to the Ciliates.

Modified From: Leblond et. al
Lindsay Hoessel 2013

The tree depicted above shows the relationship between Alexandrium tamarense and its closest relatives, A. affine, A. tamiyavanichi, A. fundyense, A. catenella. This direct linkage between all four of these species can show us other species of Alexandrium that are also toxic. This phylogenetic tree was derived from a experiment done by Leblond et. al in which they did rDNA sequencing to determine the exact ancestry of each species.

Alexandrium tamarense Common Name?

Alexandrium tamarense is also referred to as Alexandrium. It is usually referred back to its genus because there are so many species of Alexandrium that have the same relative affect of the environment. Even though the different species of Alexandrium can be separated through ribosomal DNA sequencing as explained above, they all are still contributors to PSP and Red Tide! This is why all species of Alexandrium tamarense and all of its closest relatives are commonly referred to as Alexandrium.

Next Stop: Habitat!