Nidianthus gen. nov. - A Caytonanthus - like pollen organ from the Triassic of Nidpur, M.P., India

Abstract

Nidianthus indicus gen. et sp. nov. is a synangiate pollen organ represented by more than 30 detached specimens. The compressed synangia were isolated from the Nidpur beds by bulk maceration of the Triassic shale in HF. Each synangium is elongated, radially symmetrical, appearing four-winged with a short axial attachment at base possibly representing ultimate branchlet. The four elongated pollen sacs remain attached at the base of synangium but appearing attached or free in middle and apical regions leaving four gaps at the time of dehiscence. The apical region of each pollen sac is pointed and bent inward towards the centre of synangium. Each pollen sac dehisces by a longitudinal slit along the midline of inner face. The surface of pollen sacs shows longitudinal striations. Some specimens showed a quadrangular abscission scar at the base of synangium. Cuticle of pollen sac wall showed elongated, rectangular to polygonal cells seemingly arranged in longitudinal files. Anticlinal walls thin, obscure, straight or slightly waved. Cells become narrow towards the inner margin. Many cells of pollen sac wall showed median papilla bases and cells near the apical region showed cutinized unicellular hairs. Sometimes, remains of an inner, obscurely cellular, granular membrane possibly representing a tapetal layer could also be seen on inner side of pollen sac wall. Inside each pollen sac is a single mass of pollen-grains. Pollen-grains bisaccate, bladders hemispherical or obovate showing irregular surface reticulum, Nidianthus gen. nov. closely resembles the anther-like pollen organ Caytonanthus of Caytoniales.

A Review on Some Gymnospermous Fructifications from the Triassic of Nidpur, Madhya Pradesh, India

“…They also compared Rugathecawith Bosea indica (Srivastava) from the same bed, Masculostrobusrishra [2] and Masculostrobusclathratus [1] from Chinle Formation of Arizona but their sporangia and pollen grains are different. c. Genus: Nidianthus gen nov [6] (Fig. 2…”

“…Type species: Nidianthus indicus sp.nov. Nidianthus indicus is a synangiate pollen organ described by [6] from the Triassic bed of Nidpur. The compressed synangia is cylindrical to elongate, radially symmetrical, basally attached to short axis or ultimate branchlet and composed of 4 pollen sacs.…”

“…According to [6], the report of Caytonanthus -like Nidianthus, from the Indian Triassic and its association with Glossopteris foliage, together with reported occurence of Caytonia "fruits" and Sagenopterisleaves from fossil flora of Kachchh [10], not only indicated the occurrence of Caytonia-like plants in the southern hemisphere as well as northern hemisphere but also lent support to the speculation of Caytonia, having evolved from the Permian glossopterids of the old southern continent Gondwana [15]. i. Genus -Nidistrobusgen nov. [12] ii.…”

“…Leaves of Dicroidium, Lepidopteris [45], Glandulataenia [28], and occasionally Glossopteris [14] is littered in the Nidpur shale. Diversity of microsporangiate organs are found including Pteruchus [43], Nidistrobus [7,12] Nidianthus [6] Nidpuria [33,35] and Lelestrobus [38]). The beds also yielded a diverse collection of wellpreserved mesofossils comprising seeds, synangia, and megaspores [16, 26, 29, 31-34, 40, 42, 42].…”

Macrofloral assemblage from the Early Permian Barakar Formation of Singrauli Coalfield, Son-Mahanadi Basin, India

“…Granite, gneiss, quartzite, phyllite, schist and pegmatite west of Singrauli main sub-basin are the most explored and studied rocks in terms of macrofossil studies in this Coalfield (Bhowmik & Das, 2008Bhowmik & Parveen, 2008, 2009Bose & Srivastava, 1970, 1972Chandra & Maheshwari 1988;Pant & Basu, 1973, 1977, 1978, 1979Srivastava, 1969Srivastava, , 1971Srivastava, , 1974Srivastava, , 1979Srivastava, , 1988. The present paper deals with the systematic studies of glossopterid assemblage recovered from the coal bearing sequence of Purewa Bottom seam of the Barakar Formation of Bina Colliery.…”