NAME Diplodites sweetii
AGE Late Cretaceous (Maastrichtian).   AGE span: 70.6...65.5 mya
K&J CLASSIFICATION (2000) Fungi Imperfecti, Sphaeropsidales.
FIGURE(S)
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FIGURE REFERENCE Kalgutkar RM, Nambudiri EMV, Tidwell WD. 1993. Diplodites sweetii sp. nov. from the Late Cretaceous (Maastrichtian) Deccan Intertrappean beds of India; Review of Palaeobotany and Palynology, v. 77, p. 107-118.
SPECIES, AUTHORITY D. sweetii Kalgutkar, Nambudiri & Tidwell 1993, p. 111, pl. 1, fig. 3.
LOCATION Mohgaonkalan locality in Chhindwara District, Madhya Pradesh, India. (The Deccan Intertrappean at Mohgaonkalan in Chhindwara District is now considered to be of Maastrichtian age.)
ORIG DESCRIPTION* An internal mycelium consisting of branched hyphae (pl. 3, fig. 4) ramifies through the tissue of the pericarp. No external or superficial mycelium is present. Internal hyphae are smooth, thick-walled and 3-6 µm in diameter. The ramifying hyphae were seen in close proximity with a row of pycnidia developed within the pericarp tissue (pl. 2, fig. 2). An open and split pycnidium was found on the perianth in three-dimensional view showing pseudoparenchymatous wall tissue, a pycnidial cavity, an ostiole and liberated conidia outside the fruit wall in the vicinity of the pycnidium (pl. 3, fig. 1). Morphology of the pycnidia is variable, showing a wide range of form and size. Pycnidia are globose to subglobose, 68-108 µm in diameter (pl. 1, figs. 3-5), or ovate-oblong to pyriform with a size range of 79-353 x 54-234 µm (pl. 2, figs. 4-5). They are thick-walled, dark brown, immersed (pl. 2, figs. 1, 2), erumpent (pl. 1, fig. 3; pl. 3, fig. 1) or superficial (pl. 1, fig. 4; pl. 2 fig. 4), ostiolate (pl. 1, fig. 5) or astomous when immersed (pl. 2, figs. 1-2). Pycnidia occur singly (pl 1, figs. 3-4) or aggregated in small groups (pl. 2, fig. 3) with a subicle (pl. 1, figs. 3-4) or a stroma (pl. 1, fig. 5; pl. 2, figs. 3, 6). Stroma typically dark brown to black, thick-walled, uniloculate, and covering a single pycnidium (Pl. 2, fig. 6) or a group of pycnidia (pl. 2, fig. 2) with measured stromatic tissue (pl. 2, fig. 3) around 30 µm thick on the side, 72 µm thick at the base and a pedicellate portion 90 x 36 µm. Generally, pycnidium occurs largely surrounded by the stromatic tissue and a fused pycnidial wall. The pycnidium appears raised and erumpent when pedicellate (pl. 2, fig. 6). External pycnidia are generally ostiolate. Presence of seemingly non-ostiolate pycnidia may simply represent non-median sections. Ostioles appear to develop at one end with the widening and separation of some thin-walled cells making a narrow passage to facilitate dispersal of the conidia (pl. 3, fig. 5).

Superficial immature pycnidia in tangential section (pl. 2, fig. 4; pl. 3, fig. 3) consist of a pycnidial wall surrounding a central primordial tissue of thin-walled cells. The narrow end of the pycnidium is indicative of the future ostiolar opening (pl. 2, fig. 4), while the central tissue may represent a fertile portion developing eventually into a palisade-like layer of conidiophores that lined the inner wall of the mature fructification. Mature (pl. 1, fig. 3) and relatively young (pl. 1, fig. 4) pycnidia contain conidia. Conidia are also found in close proximity to solitary and empty pycnidia (pl. 4, fig. 1). Both septate and aseptate conidia seem to occur in the same pycnidium. Conidia are one- or two-celled, of varying shapes and sizes, but distinct size ranges in the 2-celled conidia corresponding to globose and extended pycnidia were not observed. Ellipsoidal-oblong to ovate conidia are present. These are dark brown, 1-septate, obtuse, smooth, with thickened central septum. The septum is nearly twice as thick as the cell wall.

Globose conidia are generally 1-celled, somewhat lightly colored but not hyaline or smooth. The two-celled conidia are between 14-18 x 7-9 µm in size whereas globose conidia are around 7 µm in diameter. No conidiophores or their remnants were recognized in the pycnidia containing conidia, and observed conidia were without appendages.

Striations on the conidia are not a common feature; however, a few conidia with longitudinal striae were encountered.
COMMENTS* Diplodites sweetii is classified according to the system adopted by Alexopoulos & Mims (1983) for modern Fungi Imperfecti.
PUBLICATION REFERENCE Kalgutkar RM, Nambudiri EMV, Tidwell WD. 1993. Diplodites sweetii sp. nov. from the Late Cretaceous (Maastrichtian) Deccan Intertrappean beds of India; Review of Palaeobotany and Palynology, v. 77, p. 107-118.
K&J REMARKS
TYPE
ALL NAMES (Including synonyms) Diplodites sweetii
SERIAL NUMBER 346
PUBLIC COMMENTS Habitat: plant? Perianth, pericarp
structures: Ostiole; pycnidium? or perithecium? or pseudothecium?; stroma; conidia?
 *For source, see Publication Reference.