Stigonema (Nostocales, Cyanobacteria) in the Rhynie chert (Lower Devonian, Scotland)

ABSTRACTFragmentary remains of a vascular sporophyte from the Rhynie Chert are described as a new genus and species, Trichopherophyton teuchansii. The plant, which is characterised by the possession of unicellular spinous hairs, exarch xylem and laterally attached, marginally dehiscent sporangia, is assigned to the Zosterophyllophytina, but lack of information on the arrangement of sporangia prevents its more precise positioning within the subdivision. Unusual features include the combination of circinate tips to axes with almost terete xylem strands, and the lack of a thick-walled outer cortical zone. Associated axes, lacking spinous hairs, but having papillate or rhizoid-like epidermal emergences, are interpreted as likely rhizomes of Trichopherophyton. Features, such as unicellular spinous hairs, rhizoid-like emergences, circinate tipsand parenchymatous cortex are considered in relation to the functioning and growth of aplant inhabiting an early Devonian wetland.

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Microfossils from the Lower Devonian Rhynie Chert with suggested affinities to the peronosporomycetes

Journal of Paleontology ◽

10.1666/11-087.1 ◽

2012 ◽

Vol 86 (2) ◽

pp. 358-367 ◽

Cited By ~ 17

Author(s):

Michael Krings ◽

Thomas N. Taylor ◽

Edith L. Taylor ◽

Hans Kerp ◽

Hagen Hass ◽

...

Keyword(s):

Lower Devonian ◽

Microbial Mats ◽

Plant Litter ◽

Microbial Life ◽

Opaque Material ◽

New Information ◽

Single Form ◽

Rhynie Chert ◽

Thin Walled ◽

Size And Morphology

A conspicuous silicified microfossil, Frankbaronia polyspora n. gen. n. sp., occurs in plant litter and as an inhabitant of microbial mats from the Lower Devonian Rhynie chert, Aberdeenshire, Scotland. Specimens are elongate-cylindrical, oval, or spherical, thin-walled, and may possess conical or column-like surface projections. Most specimens occur isolated, some are arranged in pairs or short chains. Each specimen contains several small spheres, each in turn with a (sub)centric opaque inclusion. Immature specimens indicate that ontogenesis in this fossil includes the formation of a single centric body of opaque material that subsequently is apportioned among the developing small spheres. Frankbaronia polyspora is quite similar in size and morphology to the oogonia containing oospores seen in certain extant members of the Peronosporomycetes. The Rhynie chert is known to contain the oldest fossil evidence of the Peronosporomycetes but only a single form (Hassiella monospora) has previously been documented. The discovery of a second putative representative of this group of organisms proves that this paleoecosystem is still an important source of new information on the paleodiversity of microbial life.

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A new vascular plant from the Lower Devonian Windyfield chert, Rhynie, NE Scotland

Transactions of the Royal Society of Edinburgh Earth Sciences ◽

10.1017/s0263593300002662 ◽

1999 ◽

Vol 90 (4) ◽

pp. 331-349 ◽

Cited By ~ 21

Author(s):

Clare L. Powell ◽

Dianne Edwards ◽

Nigel H. Trewin

Keyword(s):

Lower Devonian ◽

New Genus ◽

Vascular Plant ◽

New Taxon ◽

New Genus And Species ◽

Rhynie Chert ◽

Microbial Film

AbstractTwo plants are described from fragmentary remains preserved in the Windyfield chert, situated c. 600 m from the classic Rhynie chert locality. Both are sometimes coated by a microbial film. The larger, fertile axes are placed in the new genus and species Ventarura lyonii. They possess a distinctive, sclerenchymatous middle cortex and terete xylem, and marginally dehiscent, lateral sporangia. The new taxon is similar to the Rhynie zosterophyll Trichopherophyton teuchansii, but is placed in a new genus on sporangial differences. Associated smaller axes with unicellular epidermal outgrowths lack the middle cortex of the larger axes and often have medullated protosteles. They are interpreted as subterranean rhizomes and probably belong to the new fertile taxon, but organic continuity between the two has not been demonstrated.

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