Morphology of the megaspore Lagenoisporites magnus (Chi and Hills 1976) Candilier et al. (1982), from the Carboniferous (lower Mississippian: mid-upper Tournaisian) of Bolivia

QUETGLAS, MARCELA; CECILIA MACLUF; DI PASQUO, MERCEDES

ANAIS DA ACADEMIA BRASILEIRA DE CIENCIAS.

ACAD BRASILEIRA DE CIENCIAS

Lugar: Rio de Janeiro; Año: 2019 vol. 91 p. 1 - 10

0001-3765

https://mc04.manuscriptcentral.com/aabc-scieloPublication ofAcademia Brasileira de CiênciasPrint version ISSN 0001-3765On-line version ISSN 1678-2690The morphology and structure of megaspores assigned to Lagenoisporites magnus from the Toregua Formation, Retama Group, mid-upper Tournaisian of Bolivia were studied. The analysis was performed with light, fluorescence and scanning electron microscopy. Megaspores were laterally compressed and presented a spherical body with a proximal gula, of the hologula type. Gula had an ornamentation of verrucae and the spore body presented complex processes consisting of a bulbous base and an internally partitioned projection with sharp apex. In addition to this main ornamentation, perforations were present throughout the spore surface. Megaspores showed well marked curvaturae perfectae due to the abrupt transition existing between the gula ornamentation and the spore body processes. In section view, exospore presented a three-dimensional network of fused elements and; due to the occurrence of this structure; these megaspores were assigned to heterosporous arborescent lycopsids of the Lepidocarpaceae family. Likewise, sporoderm structural elements arranged similarly to those observed in Isoetes L., evidencing that megaspores structure has remained intact inside the heterosporous lycopsids. Therefore; the L. magnus structure not only would confirm its affinity with the Lycophyta fossils but also with the extant.