Eunotia papilioforma
Furey, Lowe and Johansen 2011 Category: Eunotioid
BASIONYM: Eunotia papilioforma Furey, Lowe and Johansen 2011
Observations
Contributor: Paula Furey - March 2011
Length Range: 13-35 µm
Width Range: 3.3-4.8 µm
Striae in 10 µm: 13-16
Description
Valves are asymmetric to the apical and transapical axes, with one apex wider than the other. The ventral margin is straight to weakly concave, and the dorsal margin is convex. The apices are rounded, tapered and slightly delimited by a change in the slope of the dorsal margin. These characteristics of the apices, combined with the inset position of the helictoglossa on the ventral margin of each apex, give the apices a 'nose-like' appearance. Helictoglossae are set in at different distances from each apex (asymmetry to the transapical axis). One apical rimoportula is present at the wider apex, at the center of that apex. The distal raphe ends curve onto the valve surface. The striae are slightly radiate. Areolae approximately 50 in 10 µm.
Specimens of E. papilioforma are variable in the width of the valve apices and the relative position of the helicotoglossae. Some of this variation is a result of the plane of focus in the microscope; optical dissection is critical to observe valve morphology. Some specimens of E. papilioforma have one more attenuated apex and the helictoglossa is more removed, relative to the opposite end. The shape of the apex with the inset helictoglossa is more characteristic of E. incisa. These valves, however, are dissimilar to the overall E. incisa morphology, which lacks a strong heteropolar variation in apex width and position of the helictoglossae. Specimens of E. papilioforma are similar in morphology to the more asymmetric valves of E. rhomboidea. Eunotia papilioforma, however, is consistently wider than E. rhomboidea (as shown by Camburn et al. 1978; Krammer & Lange-Bertalot 1991). Figures 1-12 (Wuthrich 1975) were classified as E. rhomboidea but are likely more than one taxon. These illustrations show some of the variability discussed here, including variation in the width of the valve apices, position of the helicotoglossae and valve width.
In some specimens of E. rhomboidea, one apex is rounded and the other end is more shaped like the “snout of a shark”. Some specimens possess a small pseudoseptum. The pseudoseptum prevents observation of the base of the rimoportula (in SEM). The rimoportula of E. papilioforma also consistently occurS on the wider end of the valve.
Original Description
Basionym: Eunotia papilioforma
Author: Furey, Lowe and Johansen 2011
Length Range: 13-35 µm
Width Range: 3.3- 4.8 µm
Striae in 10 µm: 13-16 , areolae 50
Original Description
Frustules asymmetric to the apical and transapical axes, with one end wider than the other. Valves straight to weakly concave on the ventral margin, convex on dorsal margin, 13 – 35 μm long, 3.3 – 4.8 μm wide. Apices rounded, tapered, slightly delimited by a change in the slope of the dorsal margin, appearing nose-like. Helictoglossae set in from ends, often positioned at different distances from each end, giving appearance of an indentation in the light microscope. Rimoportula at the wider valve end, at the center of the apex. Raphe with distal ends curved onto the valve surface. Striae slightly radiate, 13 – 16 in 10 μm. Puncta 50 in 10 μm.
Original Images
Cite This Page:
Furey, P. (2011). Eunotia papilioforma. In Diatoms of the United States. Retrieved June 17, 2013, from http://westerndiatoms.colorado.edu/taxa/species/eunotia_papilioforma
Species: Eunotia papilioforma
Contributor: Paula Furey
Reviewer: Sam Rushforth
Image Credit: Paula Furey
- Valve asymmetric to apical axis
- Position of the helictoglossae asymmetric to transapical axis
- Apices 'nose-like'
- Distal raphe curves onto valve face
- One apical rimoportula
Valves asymmetric to the apical axis, that is, one apex is wider than the other. The helictoglossae are removed from the apices, in a position that is asymmetric to the transapical axis. The apices are rounded, tapered and combined with the inset helictoglossae, the apices .appear 'nose-like'. Distal raphe curves onto the valve surface. One apical rimoportula is present at the wider valve end.
Compare
The position of the helictoglossa in E. papilioforma may be more removed (central) from the apex, as in E. incisa. Valves of E. incisa, however, are symmetrical in regard to apex width and position of the helictoglossae. The type illustrations of E. rhomboidea are more or less asymmetrical about the transapical axis (Simonsen 1987, Plate 546), but in comparison to E. rhomboidea, E. papilioforma valves are consistently wider.
Eunotia incisa
Eunotia rhomboidea
Citations
Camburn, K.E., Lowe, R.L., and Stoneburner, D.L. (1978). The haptobenthic diatom flora of Long Branch Creek, South Carolina. Nova Hedwigia 30: 149-279.
Furey, P.C., Lowe, R.L. and Johansen, J.R. (2011). Eunotia Ehrenberg (Bacillariophyta) of the Great Smoky Mountains National Park, USA. Bibliotheca Diatomologica 56: 1-134.
Krammer, K. and Lange-Bertalot, H. (1991). Bacillariophyceae. 3. Teil: Centrales, Fragilariaceae, Eunotiaceae. . In Ettl, H., Gerloff, J., Heynig, H. & Mollenhauer, D. (Eds.). Süsswasserflora von Mitteleuropa. 2(3): 1-576. Gustav Fisher Verlag, Stuttgart, Germany.
Wuthrich, M. (1975). Contribution à la connaissance de la flore algologique du Parc National Suisse. Le Diatomées. [Résultats des recherches scientifiques au Parc National suisse]. Druck Lüdin, AG Liestal. Band XIV: 273-369.
Links & ID's
Index Nominum Algarum (INA)
California Academy of Sciences (CAS)
North American Diatom Ecological Database (NADED)
NADED ID:
Autecology Discussion
Eunotia papilioforma is widespread on bryophyte substrates in streams throughout the Great Smoky Mountains National Park.
Images
Type locality. Samples collected from bryophytes in Steeltrap Creek, Forney Creek watershed, Swain County, North Carolina, Great Smoky Mountains National Park.
Credit/Source: Paula C. Furey