Cestites

Cestites; Temporal range: Middle Ordovician–Middle Ordovician PreꞒ Ꞓ O S D C P T J K Pg N
	Holotype of Cestites mirabilis, from Douglas Lake Member of Lenoir Limestone, at Douglas Dam, Tennessee
Scientific classification
Kingdom:	Plantae
Division:	Marchantiophyta
Class:	Marchantiopsida
Order:	Marchantiales
Family:	Marchantiaceae
Genus:	Cestites Caster and Brooks(1956)
Type species
	Casterlorum crispum; Retallack (2019)

Cestites ("girdle") was at first considered a ctenophore,^[1] but now is regarded as genus of liverwort fossil from the Middle Ordovician (Darriwilian, 460 million years old) Douglas Lake Member of the Lenoir Limestone from Douglas Dam Tennessee.^[2]

Description

Cestites has a narrow gametophyte thallus, with a wide midrib and dichotomizing at long intervals. The archegoniophores are parasol shaped and clustered.

Biological affinities

Cestites is similar to living Marchantia.

References

^ ^a ^b Caster, K.E.; Brooks, H.K. (1956). "New fossils from the Canadian–Chazyan (Ordovician) hiatus in Tennessee". Bulletins of American Paleontology. 36: 157–199.
^ ^a ^b Retallack, G.J. (2019). "Ordovician land plants and fungi from Douglas Dam, Tennessee". The Palaeobotanist. 68: 1–33.

[Caster_and_Brooks_1956-1] Caster, K.E.; Brooks, H.K. (1956). "New fossils from the Canadian–Chazyan (Ordovician) hiatus in Tennessee". Bulletins of American Paleontology. 36: 157–199.

[Retallack_2019-2] Retallack, G.J. (2019). "Ordovician land plants and fungi from Douglas Dam, Tennessee". The Palaeobotanist. 68: 1–33.

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