NAME Plochmopeltinites cooksoniae
AGE (Ramanujam & Rao) Late Miocene; (Reddy, Ramanujam & Srisailam): Miocene.   AGE span: 23.03...5.332 mya
K&J CLASSIFICATION (2000) Ascomycetes, Microthyriales.
FIGURE(S)
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FIGURE REFERENCE Ramanujam CGK, Rao KP. 1973. On some microthyriaceous fungi from a Tertiary lignite of south India; The Palaeobotanist, v. 20 (1971), p. 203-209.
SPECIES, AUTHORITY P. cooksoniae Ramanujam & Rao 1973, p. 207, pl. 3, figs. 22-23.
LOCATION (Ramanujam & Rao) Warkalli lignite of Kerala State, India; (Reddy, Ramanujam & Srisailam): Neyveli, South Arcot district, Tamil Nadu, India.
ORIG DESCRIPTION* Ascomata superficial, discoid, rounded, brown to reddish brown, 65-166 µm in diameter, ostiolate; ostiole 10-18.5 µm in diameter, irregular in shape, more or less centric, border dense, slightly raised, of dark brown, thick-walled irregular cells; covering membrane of ascomata plectenchymatous, consisting of extremely sinuous, irregularly branched hyphae; hyphal cells 4-18 µm long, considerably thick-walled (3.5-6 µm), excepting cells of peripheral layer. Margin of fruit body not entire, formed of thin-walled membranous peripheral cells. Free hyphae, at times extending from marginal cells of ascomata, wavy.

EMENDED DESCRIPTION (Reddy, Ramanujam & Srisailam 1982, p. 116): Ascomata epiphyllous, discoid, more or less rounded to often somewhat irregular in shape, dark brown to reddish brown, 85-150 µm in diameter, ostiolate; ostiole 10-18 µm, rounded to irregular in shape, centric or slightly sub-centric, formed of broken-down central group of cells, ostiole border slightly elevated, made up of 2 or 3 layers of dark brown, thick-walled, angular cells; covering membrane of ascomata plectenchymatous, comprising sinuous, irregularly branched and intertwining hyphae showing a distinct but locally distorted radial pattern. Many hyphal branches end blindly against adjacent hyphae, hyphal branching more pronounced near margin. Cells in individual hyphae narrow, elongated, of variable size. Margin of fruiting body wavy, locally discontinuous, formed of close juxtaposition of peripheral parts of hyphal cells. Free hyphae present, extending locally beyond margin of ascoma, and associated with marginal cells.
COMMENTS* (Ramanujam & Rao): In the possession of considerably thick-walled cells forming the bulk of the plectenchymatous covering, the absence of an entire margin and the irregular ostiole, the species under report is distinguishable from Plochmopeltinites masoni described from the Upper Tertiary of Australia (Cookson, 1947a) and P. ratnami (see remarks from Kalgutkar & Jansonius (2000) below) reported from the South Arcot lignite, Madras (Ramanujam, 1963a). The species has been named in honor of Dr. Isabel Cookson. It is frequently met with in the lignite samples studied.

(Reddy, Ramanujam & Srisailam): Cookson (1947a) originally included Plochmopeltinites under Micropeltaceae, although she did mention the non-radiate nature of the ascomal construction as an important character of this family. Ramanujam & Rao (1973), too, treated this genus as a member of Micropeltaceae. Alvin & Muir (1970), however, clearly indicated that the thyriothecium of Micropeltaceae is strictly non-radiate and on this basis argued that a "Plochmopeltinites" characterized by a radiate construction, should be treated under the family Microthyriaceae.

Plochmopeltinites is a common element of the clay and lignite samples under study. The plectenchymatous covering membrane made up of irregularly branched, sinuous and intertwining hyphae aligned in a radial pattern, and the presence of a prominently rimmed ostiole are the characteristic features of Plochmopeltinites. Plochmopeltinites cooksoniae was originally recorded from the Warkalli lignites of Kerala (Ramanujam & Rao, 1973). The wavy, often irregular and discontinuous margin, the more pronounced branching of the sinuous hyphae nearer the margin and the details of the ostiole are the distinguishing features of P. cooksoniae. Plochmopeltinites fruit bodies are known frequently from the various Oligocene-Lower Miocene deposits of Australia (Cookson, 1947a; Selkirk, 1975). As of today, this genus is known in India only from the Neogene (Miocene) deposits.
PUBLICATION REFERENCE Ramanujam CGK, Rao KP. 1973. On some microthyriaceous fungi from a Tertiary lignite of south India; The Palaeobotanist, v. 20 (1971), p. 203-209.

Reddy PR, Ramanujam CGK, Srisailam K. 1982. Fungal fructifications from Neyveli lignite, Tamil Nadu--their stratigraphic and palaeoclimatic significance; Records of the Geological Survey of India, v. 114, p. 112-122.
K&J REMARKS "Plochmopeltinites ratnami" cited by Ramanujam in the abstracts published in the Proceedings of the 50th Indian Congress (1963b), and in the AUTHORS’ COMMENTS above, has not been validly published. Hence it is not included in this synopsis.
TYPE
ALL NAMES (Including synonyms) Plochmopeltinites cooksoniae
SERIAL NUMBER 1354
PUBLIC COMMENTS
 *For source, see Publication Reference.