Carteria (car-tear-ee-a) a volvocid green algal cell, with chlorophyll b in the single cup-shaped plastid - giving it a green colour. Eyespot located in plastid, visible anterior of mid line on the right margin of the plastid. Very similar to Chlamydomonas, but distinguished by having 4 flagella. Differential interference contrast. This image taken by Michele Bahr and David Patterson of material collected from the water column and the margins of Lake Toolik (Alaska, USA) in August, 2001. Image copyright: Michele Bahr and D. J. Patterson, used under license to MBL (micro*scope).
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From the collection
Lake Toolik, Arctic Alaska
|Description of Carteria: Cells mostly radially symmetrical, sometimes dorsiventrally flattened; cell shape ovoid, ellipsoidal, spherical, inverted ovoid, cylindrical or spindle-shaped; cell wall adherent to the protoplast, 4 flagella; chloroplast single, variable in shape ranging from cup-shaped, unilaterally parietal, asteroid, variously lobed and perforated, reticulate or dispersed into small pieces; pyrenoid present (1 - several); eyespot present (rarely absent); nucleus more or less central; contractile vacuoles, two or four, anteriorly located; asexual reproduction by 2-8 zoospores; sexual reproduction isogamous, anisogamous, in one species oogamous; sexual fusion of isogametes is initiated by flagellar agglutination and cell wall lysis; in one species gametic flagella soon desintegrate and gametic fusion is by aplanogamy; zygotes either planozygotes (with 4 or 8 flagella) or aplanozygotes, the latter germinate by release of a transparent vesicle enclosing 4 - 16 zoospores; mature zygotes with mostly smooth, thick cell walls, often accumulating secondary carotenoids; resting and palmelloid stages known. |