SPECIES starting with "d"

 

Decussata placenta

  1. Axial area narrow
  2. Proximal raphe ends prominent
  3. Areaolae slightly offset

Symmetrical biraphid - Valves elliptical with rostrate to rostrate-apiculate apicies. Axial area narrow, expanded at the center to form a circular central area. The raphe is filiform and straight to slightly undulate, with prominent, dilated external proximal raphe ends. Areolae from neighboring striae slightly offset, producing a quincunx pattern.


Denticula tenuis

  1. Valves lanceolate to elliptic-lanceolate
  2. Protracted apices
  3. Costae distinct
  4. Raphe eccentric

Nitzschioid - Valves lanceolate to elliptic-lanceolate, with protracted apices. The raphe is distinct, positioned off center and contained within a canal. Costae are distinct and number 5-7 in 10 µm.


Diadesmis confervacea

Navicula confervacea

  1. Valves elliptical
  2. Rounded central nodule
  3. Striae punctate

Symmetrical biraphid - Valves elliptical with apices protracted in larger specimens. There is a rounded central nodule visible when focusing on the interior of the valve. Striae are radiate, punctate and of variable length.


Diadesmis pantropica

  1. Valves linear
  2. Axial area narrow
  3. Central area round
  4. Raphe terminates in subapical nodule

Symmetrical biraphid - Valves linear, slightly swollen in center and at the ends. The axial area narrow, with a round central area. The distal raphe terminates in a subapical nodule.


Diatoma mesodon

  1. Valves elliptical-lanceolate with rounded ends
  2. Valve 6 to 12 µm long
  3. Transapical costae 3-6 in 10 µm
  4. Rimoportula single, near one valve apex

Araphid - Valves elliptical-lanceolate with broadly rounded apices. Transapical striae and costae visible in the light microscope.


Diatoma moniliformis

Diatoma tenue var. moniliforme

  1. Smaller valves elliptical with rounded ends
  2. Larger valves lanceolate with subrostrate ends
  3. Valve width most often 3-5 µm
  4. Transapical ribs 6-11 in 10 µm

Araphid - Valves elliptical to elliptical-lanceolate with rounded to subcapitate apices. Transapical ribs clearly visible under LM, striae not visible under LM.


Diatoma tenuis

Diatoma elongatum var. tenuis

  1. Valves linear with capitate ends
  2. Valves usually 3-4.5 µm wide
  3. Transapical ribs 6-11 in 10 µm

Araphid - Valves are linear with capitate apices. Transapical ribs number 6-11 in 10 µm. Striae are not distinguishable under LM. One rimoportula is positioned at one valve apex.


Diatoma vulgaris

  1. Valve elliptical to elliptical-lanceolate with rounded subrostrate ends
  2. Valve 8-12 µm wide
  3. Transapical costae 6-10 in 10 µm

Araphid - Valves elliptical to elliptical-lanceolate with broadly rounded subrostrate apices. Transapical costae visible under LM, striae not visible under LM.


Diatomella balfouriana

  1. Valves linear with rounded apices
  2. Septum present
  3. Axial area wide
  4. Proximal raphe ends distant

Symmetrical biraphid - Valves linear, with rounded apices. The axial area is wide. A septum is present extending the entire length of the valve, and has three large openings, the largest in the center, smaller two at the ends. The proximal raphe ends are relatively distant from one another; they are widely spaced.


Didymosphenia geminata

Gomphonema geminatum

  1. Valves large
  2. Headpole capitate
  3. Stigmata 2-5
  4. Apical porefield present
  5. Distal raphe deflected

Asymmetrical biraphid - The valves are large and robust. The headpole is distinctly capitate, while the footpole may be capitate or not. The number of stigmata is variable, but depends on valve size. A porefield is present at the footpole. The distal raphe is deflected at the footpole, rather than bisecting it.


Diploneis finnica

  1. Valves large and broadly elliptical
  2. Longitudinal canals broad
  3. Striae biseriate
  4. Central area small

Symmetrical biraphid - Diploneis finnica has large elliptical valves with biseriate striae and a small central area. The longitudinal canals are wide and lanceolate, 1/3 to 1/2 the width of the valve at the center.


Diprora haenaensis

  1. Single row of pores along the valve margin
  2. Frustules joined into filaments
  3. Valve mantles with apical prows
  4. Open cingulum present (but missing in adjacent frustule of this image)

Araphid - Valves are linear with broad, rounded ends; the smallest valves within the size series are nearly circular. A single row of pores is present along the valve margin. Frustules are joined into filaments. The valve mantle is extended to form apical prows, a feature visible in girdle view. Under SEM, it is possible to view an open cingulum. This species is currently known only from wet walls on the island of Hawai’i.


Distrionella incognita

  1. Valves linear with capitate ends
  2. Valves < 3 µm wide
  3. Costae 11-17 in 10 µm
  4. Striae 20-26 in 10 µm

Araphid - Valves linear with capitate ends and less than 3 µm wide. Costae number 11-17 in 10 µm. Striae number 20-26 in 10 µm.