NAME Stomiopeltites cretaceus
AGE Wealden (Early Cretaceous).   AGE span: 140.2...125 mya
K&J CLASSIFICATION (2000) Ascomycetes, Microthyriales.
FIGURE(S)
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Pl.25fig.10a.jpg
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Pl.25fig.10b.jpg
FIGURE REFERENCE Alvin KL, Muir MD. 1970. An epiphyllous fungus from the Lower Cretaceous; Biological Journal of the Linnean Society, v. 2, p. 55-59.
SPECIES, AUTHORITY S. cretaceus Alvin & Muir 1970, p. 56, pl. 1, figs. A, E.
LOCATION Near Hanover Point, Compton Bay, Isle of Wight, UK.
ORIG DESCRIPTION* Mycelium epicuticular, consisting of an extensively spreading weft of anastomosing hyphae 1.7-3 µm wide. Thyriothecia scattered, round, dimidiate, up to 0.25 mm in diameter, having when mature a single central ostiole 8-12 µm in diameter. Wall of thyriothecium composed of several layers of hyphae making up a plectenchyma of irregular, rather sinuous cells 2-3.5 µm wide, not radiating except sometimes at the margin of young thyriothecia. Presumed pycnidia 20-45 µm in diameter, having a relatively large, irregular ostiole. Wall of pycnidium lobate, smooth, plectenchymatous.
COMMENTS* The fungus occurred on the shoots of an undescribed conifer resembling Frenelopsis Schenk. In general structure the fossil compares quite strikingly to the extant genus Stomiopeltis, but equally good comparisons could be made with a number of other genera of the Stomiopeltoideae, since the genera are distinguished mainly on spore characteristics (Batista, 1959). Scanning electron micrograph of the thyriothecium and epicuticular mycelium of Stomiopeltis citri Bitancourt are shown in Plate 2 E, F; they compare quite strikingly to equivalent micrographs of the fossil (Plate 2 B, D), except that the thyriothecia in the extant species are smaller.

Stomiopeltis has been identified in the fossil record by Dilcher (1965), who described a species (S. plectilis) from the Eocene of Tennessee on the lower epidermis of Sapindus leaves. From Dilcher's photographs and description, his species is very similar in both thyriothecial and mycelial characters to Stomiopeltites cretaceus. The Tertiary species also lacked spores, so perhaps its inclusion in the extant genus cannot be regarded as unequivocal. Dilcher was uncertain whether some of the smaller fructifications were pycnidia or merely young thyriothecia; in their flat irregular form with somewhat radiating edges and non-ostiolate condition, they are comparable to what are here interpreted as young thyriothecia, and quite different from structures believed to represent pycnidia. Pycnidia have been reported in one living species of Stomiopeltis, viz., S. citri Bitancourt (1934); they resemble small thyriothecia.

Cookson (1947a) established the genus Plochmopeltinites for fossil members of this group in which spores are unknown. However, Cookson's species for which she erected the genus (P. masonii) has a thyriothecium of sinuous but radiating cells and is not therefore classifiable in the Micropeltaceae, which is distinguished from the Microthyriaceae by the strictly non-radiating thyriothecial structure (Luttrell, 1946; Batista, 1959). The genus Stomiopeltites is therefore proposed for fossil forms without spores in which the thyriothecial plectenchyma consists of irregularly arranged sinuous cells, and where a reticulate mycelium is present.
PUBLICATION REFERENCE Alvin KL, Muir MD. 1970. An epiphyllous fungus from the Lower Cretaceous; Biological Journal of the Linnean Society, v. 2, p. 55-59.
K&J REMARKS
TYPE
ALL NAMES (Including synonyms) Stomiopeltites cretaceus
SERIAL NUMBER 1653
PUBLIC COMMENTS
 *For source, see Publication Reference.