Cavinula vincentii

Antoniades & Hamilton in Antoniades et al. 2009      Category: Symmetrical biraphid
BASIONYM: Cavinula vincentii Antoniades & Hamilton in Antoniades et al. 2009

Cavinula scutiformis

 

Chamaepinnularia mediocris

LM scalebar = 10 µm = 80 pixels.



Observations

Contributor: Paul Hamilton - April 2011
Length Range: 12-15 µm
Width Range: 8-11 µm
Striae in 10 µm: 23-26

Description

Valves are elliptic. Striae are 23-26 in 10 µm, and may be greater in some valves. Areolae are 28-33 in 10 μm. The axial area is narrow and linear, broadening slightly towards the central area; the central area is round to elliptic. The raphe is filiform with expanded central fissures. The terminal raphe fissures are small on the valve face. The striae are strongly radiate, and are usually visibly punctate. Long and short striae alternate in the central area. Short striae are present extending just inside the margin of the valve face, and continuing onto the mantle. The stria density increases towards the apices. Areolae are elliptic, with depressed occlusions, and with a row of elongated areolae along the axial area that lengthen to slit-like structures around the central area. At each apex one enlarged pore-like fissure is visible immediately adjacent to the distal fissures on the primary side of the valve; this pore is elliptical on the external surface and transapically elongated on the internal surface. Internally, the raphe is linear, terminating in a small helictoglossa at the terminal fissure. Helictoglossa not present at proximal fissure. Internally, the striae are positioned between costa thickenings, and each stria is covered internally by a hymen. Valves have two or more open copulae, with one row of pores.

Navicula pseudoscutiformis was identified from the Gulf of Finland (Snoeijs and Potapova, 1995, p. 32). The specimens are similar to C. vincentii in valve shape and features, however the specimens differ from C. vincentii by a lanceolate axial area and the absence of enlarged, pore-like structures at the apices. A specimen identified as N. pseudoscutiformis (Krammer and Lange-Bertalot,1986, fig. 59: 12) is also similar to C. vincentii, however it is difficult to discern the length of the areolae around the central area. Closer examination of specimens identified as C. pseudoscutiformis may reveal their affinity to C. vincentii.



Original Description

Basionym: Cavinula vincentii
Author: Antoniades & Hamilton in Antoniades et al. 2009
Length Range: 12-15 µm
Width Range: 8-11 µm
Striae in 10 µm: 23-26

Original Description

Valvae ellipticae cum anguste rotundatis extremis. Longitudo 12-15 μm, latitudo 8-11 μm, cum 23-26 (30?) striis et 28-33 areolis in 10 μm. Axialis area angusta, linearis, dilatans leviter ad centralem aream; centralis area rotunda ad ellipticam. Raphe filiformis cum expansis centralibus fissuris. Terminalis raphis fissurae parvae super fronde. Striae valenter radiatae, fere manifesto punctatae. Longae et breves striae alternate in centralis area. Breves striae praesentes extensae modo internam marginem frondis, et continuantes deorsum limbum. Striae crassitudines crescentes versus apices. Areolae ellipticae, cum series elongatae areolae secus area axialem quam elongatam ad pseudorimas structuras circa centralem aream. Areolae cum depressis occlusis. Ad uterque apex unus ampliatus porus praesens statim adiacet distales fissures in primo latere valvae; porus ellipticus in externa pagina et transapicallis elongatus in interna pagina. Interne, raphe linearis, in parva helictoglossa ad terminalem fissuram. Helictoglossa non praesentia ad proximalem fissuram. Interne, striae positae inter costas concreties, unaquaeque stria tecta ab hymenio. Valvae cum dua vel pluris apertis copulis cum una series pori.

Original Images


Cite This Page:
Hamilton, P. (2011). Cavinula vincentii. In Diatoms of the United States. Retrieved April 17, 2014, from http://westerndiatoms.colorado.edu/taxa/species/cavinula_vincentii

Species: Cavinula vincentii

Contributor: Paul Hamilton

Reviewer: Sam Rushforth

Citations

Antoniades, D., Hamilton, P.B., Douglas, M.S.V. and Smol, J.P. (2008). Diatoms of North America: The freshwater floras of Prince Petrcik, Ellef Ringnes and northern Ellesmere Islands from the Canadian Arctic Archipelago. Iconographia Diatomologica 17.

Antoniades, D., Hamilton, P.B., Hinz, F., Douglas, M.S.V. and Smol, J.P. (2009). Seven new species of freshwater diatoms (Bacillariophyceae) from the Canadian Arctic Archipelago. Nova Hedwigia 88(1/2): 57-80.

Krammer, K. and Lange-Bertalot, H. (1986). Bacillariophyceae. 1. Teil: Naviculaceae. In: Ettl, H., J. Gerloff, H. Heynig and D. Mollenhauer (eds.) Susswasserflora von Mitteleuropa, Band 2/1. Gustav Fisher Verlag, Jena. 876 pp.

Snoeijs, P. and Potapova, M. (1995). Intercalibration and distribution of diatom species in the Baltic Sea. Vol. 3. Opulus Press, Uppsala. 126 pp.

Links & ID's

Index Nominum Algarum (INA)

Original INA

California Academy of Sciences (CAS)

North American Diatom Ecological Database (NADED)

NADED ID: 195011

Autecology Discussion

The type locality of C. vincentii is a shallow arctic pond (max. depth 1 m) near Alert (White Pond, Ellesmere Island, Nunavut, Canada) with extremely inorganic, sandy sediment. Water chemistry of the pond was: pH 8.3, specific conductivity 185 μS, total phosphorus 8.7 μg/L, total nitrogen 0.562 mg/L, dissolved organic carbon 1.9 mg/L and dissolved inorganic carbon 28.0 mg/L.