Muelleria agnellus

Bahls 2014      Category: Symmetrical biraphid
BASIONYM: Muelleria agnellus Bahls 2014

Microcostatus krasskei

 

Muelleria gibbula

LM scalebar = 10 µm = 80 pixels.



Observations

Contributor: Loren Bahls - November 2015
Length Range: 27-60 µm
Width Range: 9.5-12.3 µm
Striae in 10 µm: 13-18 at valve center, 20-24 at the apices

Description

Valves are lanceolate in smaller specimens to linear-lanceolate with slightly gibbous central margins in the largest specimens. Valve margins are convex and apices are broadly rounded. The raphe is straight and lies between two longitudinal canals. The axial area is narrow and the central area is small and elliptic. Proximal raphe ends are unilaterally deflected. Internally, a rectelevatum is present between the proximal raphe ends; distal raphe ends terminate in helictoglossae. Striae are distinctly curved and strongly radiate throughout. Striae are more distantly spaced in the valve center than in the rest of the valve. Areolae in the central striae appear larger and more distinct than areolae in more distal striae. Under SEM, external areolae openings are complex and highly variable in shape. Terminal raphe fissures are bifurcate and the two branches separate at a very wide angle of almost 180 degrees.



Original Description

Basionym: Muelleria agnellus
Author: Bahls 2014
Length Range: 26.9-59.6 µm
Width Range: 9.5-12.3 µm
Striae in 10 µm: 13-18 at valve center, 20-24 near the apices

Original Description

Valves are lanceolate to linear-lanceolate with slightly gibbous central margins in the largest specimens. Valve margins are convex and apices are broadly rounded. Valve length 26.9-59.6 μm; valve width 9.5-12.3 μm. The raphe is straight and filiform between two thickened longitudinal ribs, which occupy a narrow axial area. Proximal raphe ends are bent to the same side within a small elliptic central area. Striae are distinctly curved and strongly radiate throughout. Curved radiate striae meet short parallel striae that border the axial area at an obtuse angle, creating a criss-cross pattern near the valve apices. Areolae in the central striae appear larger and more distinct than areolae in more distal striae. Striae number 13-18 in 10 μm at valve center, 20-24 in 10 μm at the apices.

Original Images


Cite This Page:
Bahls, L. (2015). Muelleria agnellus. In Diatoms of the United States. Retrieved October 18, 2017, from http://westerndiatoms.colorado.edu/taxa/species/muelleria_agnellus

Species: Muelleria agnellus

Contributor: Loren Bahls

Reviewer: Bart Van de Vijver

Citations

Bahls, L. (2014). New diatoms from the American West–A tribute to citizen science. Proceedings of the Academy of Natural Sciences of Philadelphia 163: 61-84.

Spaulding, S.A. and Stoermer, E.F. (1997). Taxonomy and distribution of the genus Muelleria Frenguelli. Diatom Research 12: 95-113.

Spaulding, S.A., Kociolek, J.P. and Wong, D. (1999). A taxonomic and systematic revision of the genus Muelleria (Bacillariophyta). Phycologia 38: 314-341.

Van de Vijver, B., Mataloni, G., Stanish, L. and Spaulding, S.A. (2010). New and interesting species of the genus Muelleria (Bacillariophyta) from the Antarctic region and South Africa. Phycologia 49: 22-41. 10.2216/09-27.1

Links & ID's

Index Nominum Algarum (INA)

Original INA

California Academy of Sciences (CAS)

North American Diatom Ecological Database (NADED)

NADED ID:

Autecology Discussion

Muelleria agnellus has been collected from mossy pools in the alpine zones of the Mission Mountains in Montana and the Wind River Mountains in Wyoming (photos below). These pools lie at elevations of 7,940 feet and 12,319 feet, respectively.

Images

Mossy pools on Horse Ridge in the Wind River Range, Fremont County, Wyoming: home of Muelleria agnellus.

Credit/Source: Beverly Boynton, Adventurers and Scientists for Conservation.

Closeup of mossy pool on Horse Ridge where Muelleria agnellus was collected.

Credit/Source: Beverly Boynton, Adventurers and Scientists for Conservation.

Mossy pool in the Mission Mountains, Missoula County, Montana: type locality of Muelleria agnellus.

Credit/Source: Bill Agnew, Adventurers and Scientists for Conservation