Nematophyta

Nematophyta Temporal range: Cambrian–410 PreЄ Є O S D C P T J K Pg N Upper Silurian – lowermost Devonian
File:Cosmochlaina.png
Cuticle of Cosmochlaina, retrieved from the Burgsvik beds by acid maceration. Cells about 12 μm in diameter.
Scientific classification
Kingdom:	Plantae (?)
Phylum:	Nematophyta Lang, 1937
Genera
Family Nematothallaceae: Nematothallus Lang, 1937 Cosmochlaina Edwards, 1986 Family Nematophytaceae: Nematoplexus Lyon, 1962 Nematasketum Burgess and Edwards, 1988 Prototaxites Dawson, 1859

The Nematophyta or nematophytes are a paraphyletic group of land organisms, probably including some plants as well as algae known only from the fossil record, from the Silurian period until the early Devonian Rhynie chert. The type genus Nematothallus, which typifies the group, was first described by Lang in 1933, who envisioned it being a thallose plant with tubular features and sporophytes, covered by a cuticle which preserved impressions of the underlying cells. He had found abundant disaggregated remains of all three features, none of which were connected to another, leaving his reconstruction of the phytodebris as parts of a single organism highly conjectural. No reproductive or vegetative structures common to the land plants are known, and certain members of the nematophyte plexus (including Nemataplexus, axial conjugations of banded and branching tubes) seem to belong to the fungi.

The lack of a clear definition of the nematophytes has led to it being used as a wastebasket taxon, with all manner of tubes and cell-patterned cuticles from around the Silurian being dubbed "nematophytic" more as a statement of ignorance than as a scientifically meaningful statement.

Nematophytes, including cuticle and banded tubes, have been found in coprolites that were apparently produced by millipedes.

References

• McGregor and Narbonne (1978): "Upper Silurian trilete spores and other microfossils from the Read Bay Formation, Cornwallis Island, Canadian Arctic"