NAME Spirotremesporites
AGE    AGE span:  mya
K&J CLASSIFICATION (2000) Fungi Imperfecti, Amerosporae.
FIGURE(S)
FIGURE REFERENCE
SPECIES, AUTHORITY Spirotremesporites Dueñas-Jimenez 1979, p. 564; emend. Elsik 1990a.
LOCATION
ORIG DESCRIPTION* ORIGINAL DIAGNOSIS: Ellipsoidal to elongate fungal spores possessing one or several spiraling furrows. [Jansonius & Hills (1980), card no. 3769.]

EMENDED DIAGNOSIS (Elsik 1990a, p. 163): Psilate, aseptate fungal spores. The aperture is a single furrow at an angle to the axis of the spore, straight or curved to S-shaped or sigmoidal in outline, or spiral around the spore axis. The furrow can be short and straight, entirely visible on one face of the spore; longer and curved; or long and spiral around the outside of the spore. The spore wall is generally rigid. The spore outline is elongate elliptical to oval, sometimes somewhat reniform in side view, i.e. with bilateral symmetry. The ends of the spore can be similar or dissimilar; one end can be truncated by an attachment scar.
COMMENTS* (Elsik): Dueñas-Jimenez (1979) gave the number of apertures as one or several spiralling furrows. The genus is emended to include only spores with one furrow. As contrasted to the straight, longitudinally parallel furrow of Hypoxylonites, Spirotremesporites has a furrow that is set at an angle to the axis of the spore, at least for some part of the length of the furrow. Spiral dehiscences are not unique to the fungi. Miller & Wood (1982) have described a similar feature seen in Palaeozoic leiofusids, Acritarcha, as a trochispiral suture. As yet the dehiscence, or excystment, style does not play a part in leiofusid taxonomy. The trochospiral suture is found in both Leiofusa tumida Downie 1959 and Eupoikilofusa cantabrica (Cramer) Cramer 1971 (op. cit.). Neither of the acritarchs have the pigmented wall (Wood, pers. comm., 1983) of Spirotremesporites, however.

Affinity: Xylariaceae (Table 4). A number of genera in the Xylariaceae apparently are characterized by the helical germ slit (Dargan et. al., 1984). The spores of Helicogermslita celastri (Kale & Kale) Lodha & Hawksworth 1983 (op. cit.) are monocellate and have a tightly spiral furrow which traverses the spore at least three times. The angle of obliqueness of the furrow can be very low, as in spores of Xylaria polymorpha (Rogers & Callan, 1986), which otherwise are very similar to Hypoxylonites sulekii. Anthostomella mamnioides also apparently has a spore with a spiral furrow (Shoemaker, 1978).
PUBLICATION REFERENCE Dueñas-Jimenez H. 1979. Estudio palinologico de los 35 mts. superiores de la seccion Tarragona, Sabana de Bogata; Caldasia, v. 12, p. 539-571.

Jansonius J, Hills LV. 1980. Genera file of fossil spores - supplement 4; Special Publication, Department of Geology, University of Calgary, cards 3629-3800.

Elsik WC. 1990. Hypoxylonites and Spirotremesporites, form genera for Eocene to Pleistocene fungal spores bearing a single furrow; Palaeontographica, Abt. B, v. 216, p.137-169.
K&J REMARKS Spirotremesporites thus emended comprises 11 species. Elsik tended to interpret those forms in which more than one furrow is visible on the face facing the observer as having one long furrow that loops several times around the grain. Kalgutkar and Jansonius (2000) doubt that that is true for all species (see, e.g., S. ecuatorialis).
TYPE TYPE: Spirotremesporites simplex Dueñas-Jimenez 1979, p. 564, pl. 3, fig. 5.
ALL NAMES (Including synonyms) Varisulcosporites Rouse & Mustard 1997.; Spirotremesporites;
SERIAL NUMBER 1587
PUBLIC COMMENTS
 *For source, see Publication Reference.