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SPECIES starting with "t"


Tabellaria fenestrata

  1. Central inflation wide
  2. Central striae reach axial line
  3. Girdle bands open
  4. Septae present

Araphid - The central inflation is as wide, or slightly wider, than the capitate apices. Central striae reach the axial line, so there is no hyaline central area. Girdle bands open, with regular septae. Rudimentary septae are absent. Marginal spines are absent.

Tabellaria flocculosa

  1. Central valve inflation wide
  2. Hyaline central area
  3. Septae present
  4. Marginal spines

Araphid - Valves with central valve inflation and capitate, to slightly capitate ends. The central inflation is wider than the terminal inflation. A hyaline area is present in the central valve. Marginal spines are present. A rimoportula is located near the central area. Regular and rudimentary septa are present on closed girdle bands.

Tabularia fasciculata

Fragilaria fasciculata
Echinella fasciculata
Ctenophora pulchella var. fasciculata

  1. Valves linear-lanceolate to lanceolate
  2. Axial area very broad
  3. Distinct central area not evident
  4. Striae costate

Araphid - Valves are linear-lanceolate to lanceolate. The apices are set off slightly, rounded but not capitate. The axial area is very broad. No central area is evident. Striae are costate.

Terpsinoë musica

  1. Valves generally triundulate
  2. Pseudocelli present
  3. Rimoportulae present
  4. Silica bars present

Centric - Valves are triundulate, except in specimens at the lower end of the size spectrum. Pseudocelli are present at valve apicies.The inflations are almost equal in width. The middle inflation contains a rimoportula, positioned slightly off center. The areolae are coarse and randomly arranged. In girdle view, the silica bars resemble music notes.

Tetracyclus glans

Odontidium glans

  1. Central inflation large
  2. Costae coarse
  3. Valve ends rounded, with apices pointed
  4. Sternum narrow
  5. Septum present

Araphid - Valves are ellliptic-lanceolate with a large central inflation and rounded to pointed apices. The costae are thick and evenly spaced at 2-3 in 10 µm. The axial area is narrow and linear, sometimes with poorly defined margins. Girdle bands contain septa that extend from alternating ends in adjacent bands.

Tetracyclus hinziae

  1. Valves lanceolate-elliptic with cuneate to rounded ends
  2. Rimoportula present
  3. Septa present

Araphid - Valves are lanceolate-elliptic, with rounded to cuneate ends. A single rimoportula is located between the first and second costa, near the sternum. Septa are present and alternate between poles in adjacent copulae. Costae number 1-3 in 10 µm. Striae number 20-27 in 10 µm.

Tetracyclus rupestris

Gomphogramma rupestre

  1. Valves elliptic-lanceolate
  2. Septae distinct
  3. Costae robust, parallel
  4. Rimoportula present

Araphid - Valves are elliptic-lanceolate, with broadly rounded apices. Septae are distinct and extend approximately 1/4 of the way into the valve. Septae alternate orientation from one band to the next. Costae are robust and parallel. A single rimoportula is present at one valve end.

Thalassiosira baltica

Cocinodiscus balticus

  1. Valve face flat
  2. Areolae coarse
  3. Central fultoportulae up to 7
  4. Rimoportulae 3

Centric - The valve face is flat. Areolae are coarse and radiate from the valve center in sectored rows. Three rimoportulae are present on the valve face, closer to the valve margin than to the center of the valve.

Thalassiosira lacustris

Cyclotella punctata
Stephanodiscus punctatus

  1. Valve faces tangentially undulate
  2. Striae coarse
  3. Several marginal fultoportulae present
  4. Single marginal rimoportula present

Centric - The valve face is tangentially undulate. Striae are coarse and organized into somewhat radial rows. A ring of marginal fultoportulae is present. A prominent rimoportula is present on the valve face, close to the margin.

Thalassiosira weissflogii

Eupodiscus weissflogii
Conticribra weissflogii

  1. Valves flat
  2. Areolae fine
  3. Prominent rimoportula on valve margin

Centric - Valves are flat, with short mantles. Areolae are fine. A single, prominent rimoportula is present on the valve margin.

Tryblionella apiculata

Nitzschia apiculata

  1. Valves constricted at central margin
  2. Apices apiculate to sub-capitate
  3. Longitudinal fold present
  4. Fibulae aligned with striae

Nitzschioid - Valves are constricted in the middle on both sides of valve. The apices are apiculate to subcapitate. A longitudinal fold present, forming a hyaline area. Fibulae and striae are equal in number and aligned with one another.

Tryblionella calida

  1. Valves slightly concave in the middle of the valve
  2. Apices protracted, narrowly rounded
  3. Narrow, indistinct fold present
  4. Transapical ribs distinct, 12-16 in 10 µm
  5. Fibulae number 7-9 in 10 µm

Nitzschioid - Valves are linear and slightly concave in the middle of the valve. The apices narrow, drawn out and narrowly rounded. A narrow, indistinct fold runs along the longitudinal axis of the valve. The fold is barely undulate, or may not appear elevated or depressed from the main valve surface. Transapical ribs are distinct. Striae are indistinct.

Tryblionella gracilis

Nitzschia tryblionella

  1. Valve fusiform
  2. Apices cuneate
  3. Longitudinal undulation distinct
  4. Costae and fibulae faint

Nitzschioid - Valves large and fusiorm.The longitudinal undulation is distinct. Both transapical costae and fibulae are relatively faint. Striae are difficult to observe with LM.

Tryblionella hungarica

  1. Valve length 35-100 µm
  2. Ends protracted slightly and bluntly rounded
  3. The longitudinal fold is wide, running the length of the valve
  4. Fibulae distinct, numbering 8-11 in 10 µm

Nitzschioid - Valves linear, slightly concave in the middle, with the ends protracted slightly and bluntly rounded. Raphe keel with distinct fibulae numbering 8-11 in 10 µm. A longitudinal fold is wide, running the entire length of the valve.