Wall morphology was monitored by light microscopy of permanent preparations, and a number of morphometric measurements obtained. parvulum were isolated and maintained in liquid medium under standard conditions, harvesting old cultures after each sub-culturing event. Methods - Clonal cultures of strains of G. As part of a study to investigate the ecophysiology of this taxon in relation to its use as a bio-indicator, clones from a range of sites in the UK were established and maintained in culture, monitoring their growth and morphology over extended periods of time. stodderi also has apical pore fields at both poles.īackground and aims - Gomphonema parvulum sensu lato contains a number of morphologically distinguishable varieties and forms that also show variation in their distribution and ecological ranges.
stodderi were observed to be motile and to have plastids similar to those of Encyonema species. An extant population of the very rare Kurtkrammeria stodderi is described from Montana, USA. Kurtkrammeria species consistently occur in oligotrophic or dystrophic waters with very low specific conductance and circumneutral pH. subspicula – appear to be widely distributed. Most species are local or regional endemics and only four species – K. Kurtkrammeria is a genus of remote and undeveloped regions from the Arctic to the Tropics, in both the Old World and New World. Species of Kurtkrammeria are reported infrequently from fossil deposits and from recent diatom assemblages.
Some species of Kurtkrammeria also have dorsal stigmata, apical pore fields and internal anastomosing costae at both poles, and lateral papilla-like projections from intercostae into internal areola openings. The new genus Kurtkrammeria is erected to include 13 species assigned to Encyonopsis that have (1) slit-like or crescent-shaped areolae aligned lengthwise along the apical axis, (2) striae convergent at the apices, and (3) internal proximal raphe ends hooked strongly towards the dorsal side of the valve. The species is common to abundant on stones from relatively clean stream waters from North Tianmu Mountain. vulgata, all of which show similarities to Cymbella liyangensis but differ in details of size, valve shape, stria density and structure, and number of stigmata. liyangensis are: moderately dorsiventral, semi-lanceolate valves with broadly to obtusely rounded ends indistinct central area on the dorsal side, bordered by 1–2 shorter central striae three or four round, different-sized stigmata open at the ends of the central ventral striae a “ridge like” structure is present at the junction of the valve face and mantle around the valve a marked tendency to develop biseriate striae, with up to 10 biseriate striae near the apices.
liyangensis is presented, based on light and scanning electron microscopy. A detailed morphological description of C. inaequidentata, which also has almost parallel valve margins.ĭuring a survey of freshwater diatoms from streams in North Tianmu Mountain, Liyang City, Jiangsu Province, China, a new Cymbella species, Cymbella liyangensis sp. In the genus Hannaea, some taxa lack the strongly buttressed central area as in H. The development of frustule/valve shape, central area, sternum, virga, vimine, rimoportula and ocellulimbus etc. The lack of transverse perizonium bands may be the cause of the initial 'chaos' process during its developing period from the initial cell to the normal vegetative cell. From initial cell to normal vegetative cell, the developmental sequence goes from 'chaos to order' as happens in many phenomena in the universe. The normal vegetative cell has a regular outline and exhibits a significant length reduction so that the largest valve is at least four times longer than the smallest. The pre-normal vegetative cell cannot form ribbon-like colonies, has a wide variety of irregular outlines and is composed of two cell types: one with its epivalve composed of either the initial epivalve or the initial hy-povalve, its hypovalve being newly formed, the other with both its epivalve and hypovalve newly formed. The initial cell has a cylinder-like and a frequently twisted outline, a longitudinal perizonium wholly covering the valve surface, and a disc-shaped incunabular scale, but lacks any transverse perizonium bands.
#QLAB TOOTHBRUSHES SERIES#
inaequidentata into the following four series of successive stages: auxospore, initial cell, pre-normal vegetative cell, and normal vegetative cell. Abstract This study presents observations on three species of Hannaea and documents and illustrates the life history of H. Citation: Liu B, Williams DM (2020) From chaos to order: the life history of Hannaea inaequidentata (Lagerstedt) Genkal and Kharitonov (Bacillariophyta), from initial cells to vegetative cells.
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