NAME Frasnacritetrus
AGE    AGE span:  mya
K&J CLASSIFICATION (2000) Fungi Imperfecti, Staurosporae.
FIGURE(S)
FIGURE REFERENCE
SPECIES, AUTHORITY Frasnacritetrus Taugourdeau 1968, p. 3.
LOCATION
ORIG DESCRIPTION* ORIGINAL DIAGNOSIS: Organic-walled microorganisms, generally of subcylindrical shape tending to a rounded or slightly bell-shaped parallelepiped, in transversal section nearly circular at one pole, becoming rectangular with rounded corners at the opposite pole which carries four hollow horns (or "processes") that extend the ribs of the body. [Jansonius & Hills (1987), card no. 4429.]

EMENDED DIAGNOSIS (Saxena & Sarkar 1986, p. 212): Microfossils having two to four processes. Body subrectangular, unicellular or divided into chambers by septa, smooth or variously sculptured. Processes mostly smooth but may also be sculptured, unicellular or septate. [Emended description]: Main body of the microfossils generally rectangular-subrectangular but variously shaped; either unicellular or divided into longitudinal chambers by vertical septa or multichambered, being divided by both vertical and transverse septa; septa may be complete or incomplete, sometimes septa faintly developed; body either smooth or ornamented with grana, verrucae or coni, etc., sculpturing elements may be closely or sparsely or evenly distributed. Two to four processes arising from one end of the body (although in Frasnacritetrus sp. 4, three processes are attached at the end of the body while the fourth one comes out from the middle of the body); generally broader at the base and tapering towards the apices; cylindrical or ribbon-like; either aseptate-unicellular or septate, septa one to many in each process; apex of processes pointed or blunt. Frasnacritetrus is not comparable to any of the known fossil palynogenera.
COMMENTS* (Taugourdeau): This unfortunately single example does not resemble any microfossil already described. First off, the presence of a single specimen cannot entirely eliminate the possibility of contamination, However, one does not see in the present day environment anything that corresponds to our specimen. In addition, its color and appearance are exactly the same as those of associated microfossils. Although chemical treatment has a tendency to make uniform all the material treated, the objects derived from pollution generally stay paler (yellow) and not brown as in this case. Next, one can ask if it is a fragment of an organism. The first idea that comes to mind is that it is a broken Diacrodian but the fact that the base is perfectly intact, and enclosed except at the center, does not allow to maintain this hypothesis. A second possibility, but pure speculation, would be that it is half an organism, with half missing in the manner of half cells of some Conjugales (Desmidiales), a connection being made by the central hole. One could also conceive something like a linear colony such as certain Desmochitina or hydrozoans. The fact that the base is bigger than the upper part does not easily allow one to imagine a link or connection made other than by means of quite a long tube.

(Saxena & Sarkar): The generic diagnosis of Frasnacritetrus as originally proposed by Taugourdeau, only accommodates microfossils with four processes, whereas in the present study we have also recovered specimens with three processes. Specimens with only two processes have also been recorded by Sharma (1976, pl. 1, fig. 3). Except for the difference in number of processes, there is no major morphological difference between the specimens which could justify the erection of a new genus.

Saccardo (1880, 1886) classified similar forms under the Staurosporae, which include spores having a forked or star-shaped appearance (Subramanian, 1971, p. 32). Kendrick & Carmichael (1973) published a list of staurosporous genera and their illustrations. A comparison of the present microfossils with these genera reveals a close resemblance with Tetraploa, a genus belonging to the dematiaceous Hyphomycetes, and in all probability they belong to it; hence their placement under Acritarcha incertae sedis by Taugourdeau (1968) does not seem justified. It is interesting to note that in all the seven assemblages where from the present microfossils have been recovered, also graminaceous pollen grains occur. Since Tetraploa mainly grows on Gramineae, the association of Frasnacritetrus with graminaceous pollen grains may be considered as supporting evidence for the affinity of Frasnacritetrus with Tetraploa.
PUBLICATION REFERENCE Taugourdeau P. 1968. Sur un curieux microfossile incertae sedis du Frasnien du Boulonnais, Frasnacritetrus nov. gen. (Acritarche); Cahiers de Micropaléontologie, série 1. no. 10 (Archives originales du Centre de Documentation du C.N.R.S. no. 452). p. 1-4.

Jansonius J, Hills LV. 1987. Genera file of fossil spores - supplement 9; Special Publication, Department of Geology, University of Calgary, cards 4361-4575.

Saxena RK, Sarkar S. 1986. Morphological study of Frasnacritetrus Taugourdeau emend. from the Tertiary sediments of Himachal Pradesh, India; Review of Palaeobotany and Palynology, v. 46, p. 209-225.
K&J REMARKS Saxena & Sarkar (1986) emended the genus, to allow inclusion of a number of Miocene fungal conidia that show a general similarity to the morphology of Tetraploa. This fungus generally grows on Gramineae, and the Miocene species occur in association with grass pollen. Saxena & Sarkar adduced this to support their suggestion that Frasnacritetrus should not be considered an acritarch but a form genus with affinity to Tetraploa. [Jansonius & Hills (1987), card no. 4429.]

Taugourdeau had contemplated the possibility that the single type specimen might be a contaminant, but rejected that notion because: 1) he did not know a similar form to occur in nature at present day; 2) the brown color of the specimen was unlike the bright wall of recognized modern contaminants, and in overall aspect blended in with authentic Devonian forms. The type sample is a siltstone, collected in the quarry of a brick factory. Saxena & Sarkar did not further discuss the possibility of contamination, and also had not reexamined the holotype [Jansonius & Hills (1987), card no. 4429].

Fossil forms assignable to this genus have been described under the genus Tetraploa, an extant dematiaceous fungus. Such forms may have to be reassigned to the genus Frasnacritetrus. However, if it can be proven that the type of Frasnacritetrus is a recent contaminant, the latter name may become a junior synonym of Tetraploa.

See also remarks from Kalgutkar and Jansonius (2000) under Eoglobella.
TYPE TYPE: Frasnacritetrus josettae Taugourdeau 1968, p. 3, pl. 1, figs. 1-4.
ALL NAMES (Including synonyms) Frasnacritetrus;
SERIAL NUMBER 596
PUBLIC COMMENTS
 *For source, see Publication Reference.