E. F. Stoermer
S. A. Spaulding
1997
<p><i>Navicula gibbula</i><span> Cleve and its allies have a number of morphological characters which are visible under the light microscope and distinguish them from taxa included in </span><i>Navicula</i><span> Bory sensu stricto. These include proximal raphe ends which are sharply and unilaterally hooked and often extend beyond the central area, as well as two apparently thickened longitudinal ribs which extend the length of the valve on either side of the raphe. With the use of the SEM additional well-defined characters of the </span><i>N. gibbula</i><span> complex become apparent. Distal raphe ends are bifurcate and the valve face and mantle possess bipartite walls similar to those in </span><i>Neidium</i><span> Pfitzer. Furthermore, the apparently thickened longitudinal ribs are actually hollow canals, a feature reminiscent of the longitudinal canals of </span><i>Diploneis</i><span> Ehrenberg. Characters of the group are particularly well-defined and distinct from those of other genera, justifying separation from </span><i>Navicula</i><span>. Based on the valve morphology of </span><i>N. gibbula</i><span> and all other members of the section </span><i>Naviculae fistulatae</i><span> McCall, we separate these taxa from </span><i>Navicula</i><span> and resurrect the genus </span><i>Muelleria</i><span> Frenguelli to include them.</span></p>
application/pdf
10.1080/0269249X.1997.9705405
en
Taylor & Francis
Taxonomy and distribution of the genus Muelleria frenguelli
article