NAME Asterothyrites
AGE    AGE span:  mya
K&J CLASSIFICATION (2000) Ascomycetes, Microthyriales.
FIGURE(S)
FIGURE REFERENCE
SPECIES, AUTHORITY Asterothyrites Cookson 1947a, p. 209; emend.
LOCATION
ORIG DESCRIPTION* ORIGINAL DIAGNOSIS: Mycelium superficial, persistent. Ascomata round, flat, radiate. Ascospores unknown.

DIAGNOSIS AS EMENDED (Kalgutkar & Jansonius 2000): Ascomata circular with radially arranged hyphae laterally interconnected to form a pseudoparenchymatous tissue. Cells isodiametric, squarish or elongate rectangular. Ascomata ostiolate; ostiole simple, not surrounded by a collar or thickened tissue, small or large, of irregular shape or with a regular outline. Ostiole probably formed by lysogenetic dissolution of central cell(s); small ostioles may result from rupture, or (stellate) fissure in the central part of the pseudoparenchyma.
COMMENTS*
PUBLICATION REFERENCE Cookson IC. 1947. Fossil fungi from Tertiary deposits in the southern hemisphere. Part I; Proceedings of the Linnean Society of New South Wales, v. 72, p. 207-214.
K&J REMARKS With reference to Asterothyrites, Elsik (1978) made the following comments: "Jansonius & Hills (1976) designated Asterothyrites minutus as the type species. Andrews (1955) earlier had listed A. sinuatus in his index of generic names of fossil plants [the first species described; this was avowed not to constitute a designation as lectotype]. However, the material illustrated for Asterothyrites by Cookson (1947a) can all be transferred to Phragmothyrites, except perhaps the specimens with a stellate dehiscence mark. Unfortunately, the stellate initial cell is mentioned only in the description of A. sinuatus but [only] illustrated [and not mentioned] for A. minutus (Cookson, 1947a). Dilcher (1965) further compounded the picture by assigning a new species, the type specimen of which lacks the central, diagnostic portion due to a large circular rupture.

"This genus could be salvaged for forms with a stellate dehiscence mark if it can be shown that the illustrations for A. sinuatus and A. minutus were mislabelled, as were the illustrations for Notothyrites and Plochmopeltinites (Cookson, 1947b) in a subsequent paper."

Cookson's original generic diagnosis did not address the presence or absence of an ostiole, or the presence of a central stellate cell or fissure, which many now consider a diagnostic character in Asterothyrites (as the name possibly seems to imply).

However, Cookson assigned four species to her new genus; the smallest of these is named A. minutus. The illustration of its type shows a small stellate stoma or fissure. Even if that feature was not addressed in the original species description, its presence is unmistakeable.

Kalgutkar and Jansonius (2000) are not fully convinced that the central fissure in A. minutus is an ostiole. Possibly a re-examination of the type material would decide this matter. In the mean time, Kalgutkar and Jansonius (2000) think that there may be a range from small to large ostioles, and assign to Asterothyrites all microthyriaceous species with a central ostiole, whether it is a small (stellate) split, a larger stellate fissure [as described in A. spinulatus by (Dilcher 1965) comb. nov.], or a larger solution ostiole without a regular boundary (as in A. tennesseensis Dilcher 1965); the name Asterothyrites has priority over Paramicrothallites. Paramicrothallites was proposed by Jain & Gupta (1970) for microthyriaceous forms with an ostiole; it was split off Microthallites on the basis of being ostiolate, and no further mention was made of the fact that Dilcher erected Microthallites as different from Microthyriacites Cookson on the basis of an evident absence of free hyphae. Kalgutkar and Jansonius (2000) do not consider the lack of free hyphae an important character in separating what are essentially dispersed fructifications, and include Microthyriacites in Phragmothyrites.

Ostiolate forms with a dark raised collar or platform delimiting the ostiole are assigned to Trichothyrites (in which Kalgutkar and Jansonius (2000) include Nothothyrites). Species lacking an ostiole are included in the genus Phragmothyrites.

In [their] attempt at a more logical grouping of the microthyriaceous ascomata, Kalgutkar and Jansonius (2000) accordingly emend the diagnoses of Phragmothyrites and Asterothyrites.
TYPE TYPE: Asterothyrites minutus Cookson 1947a, p. 209, pl. 12, fig. 10 [lectotype, selected by Jansonius & Hills (1976), card no. 186].
ALL NAMES (Including synonyms) Paramicrothallites Jain & Gupta 1970. ; Asterothyrites;
SERIAL NUMBER 66
PUBLIC COMMENTS
 *For source, see Publication Reference.