Rhoicosphenia californica

Thomas and Kociolek 2015      Category: Asymmetrical biraphid
BASIONYM: Rhoicosphenia californica Thomas and Kociolek 2015

REPORTED AS: Rhoicosphenia abbreviata ((Agardh) Lange-Bertalot 1980) 

Rhoicosphenia abbreviata

 

Rhoicosphenia stoermeri

LM scalebar = 10 µm = 80 pixels.



Observations

Contributor: Evan Thomas - May 2015
Length Range: 8-50 µm
Width Range: 3-6 µm
Striae in 10 µm: 11-12 in the center valve, 13-15 at the ends

Description

Frustules are clavate and strongly flexed in girdle view. Valves are heteropolar in valve view, linear-lanceolate with protracted apices in larger specimens and rounded apices in smaller specimens. Frustules are heterovalvate; one valve is concave with long raphe branches (raphe valve), one valve convex with shortened raphe branches (reduced raphe valve). On the raphe valve, the raphe is filiform. The proximal raphe ends are dilated externally and crook-shaped internally in same direction. The distal raphe ends curve in same direction externally. Internally the raphe ends terminate in in helictoglossae. The axial area is narrow, widening to form a small, ovate central area. Striae are parallel to radiate in the center of the valve and radiate at the apices. The striae are composed of round to lineate areolae, 40 in 10 μm. On the reduced raphe valve, raphe branches are 3–5 μm long at head pole, and do not extend beyond the pseudoseptum. Raphe branches are 5–7 μm long at foot pole. The external proximal ends are not expanded. The internal proximal ends are crook-shaped in same direction. The distal ends are not inflated externally and terminate in helictoglossae internally. Striae are parallel throughout. Both valves with pseudosepta at each apex, 3–8 μm long. Both valves with apical pore field at the foot pole, in which porelli number 4 per 1 μm. Girdle bands are open.



Original Description

Basionym: Rhoicosphenia californica
Author: Thomas and Kociolek 2015
Length Range: 8-50 µm
Width Range: 3-6 µm
Striae in 10 µm: 11-12 in the center valve, 13-15 at the ends

Original Description

Frustules clavate and strongly flexed in girdle view. Valves heteropolar in valve view, linear-lanceolate with protracted apices in larger specimens and rounded apices in smaller specimens, 8–50 μm long, 3–6 μm wide. Frustules heterovalvate, one valve concave with long raphe branches (R-valve), one valve convex with shortened raphe branches (D-valve). R-valve: raphe filiform, proximal raphe ends dilated externally, crook-shaped internally in same direction, distal raphe ends curved in same direction externally ending in helictoglossae internally. Axial area narrow, widening at small ovate central area. Striae parallel to radiate in center of the valve and radiate at apices, 11–12 striae in 10 μm at center of valve, 13–15 striae in 10 μm at apices, composed of round to lineolate areolae, 40 in 10 μm. D-valve: raphe branches 3–5 μm long at head pole, not extending beyond pseudoseptum, and 5–7 μm long at foot pole, external proximal ends not expanded, internal proximal ends crook-shaped in same direction and distal ends not inflated externally, terminate in helictoglossae internally. Striae parallel throughout, 12–14 striae in 10 μm at center of valve, 13–16 striae in 10 μm at apices, composed of round to lineolate areolae. Both valves with pseudosepta at each apex, 3–8 μm long. Both valves with apical pore field at foot pole, porelli 4 per 1 μm. Girdle bands open.

Original Images


Cite This Page:
Thomas, E. (2015). Rhoicosphenia californica. In Diatoms of the United States. Retrieved August 20, 2017, from http://westerndiatoms.colorado.edu/taxa/species/rhoicosphenia_californica

Species: Rhoicosphenia californica

Contributor: Evan Thomas

Reviewer: Marina Potapova

Citations

Levkov, Z., Mihalić K.C. and Ector, L. (2010). A taxonomical study of Rhoicosphenia Grunow (Bacillariophyceae) with a key for identification of selected taxa. Fottea 10(2): 145–200.

Thomas, E.W. and Kociolek, J.P. (2015). Taxonomy of three new Rhoicosphenia (Bacillariophyta) species from California, USA. Phytotaxa 204(1): 1-21. doi:10.11646/phytotaxa.204.1.1

Thomas, E.W., Kociolek, J.P. and Balasubramanian, K. . (2014). Four new Rhoicosphenia species from fossil deposits in India and North America. Diatom Research. 10.1080/0269249X.2014.961554

Links & ID's

Index Nominum Algarum (INA)

Original INA

California Academy of Sciences (CAS)

North American Diatom Ecological Database (NADED)

NADED ID:

Autecology Discussion