A revision of the Late Triassic Bintan fl ora from the Riau Archipelago (Indonesia)

In 1951, W.J. Jongmans published the description of a small flora from Bintan Island in the Riau Archipelago of Indonesia, based on material from one fossil locality in the Bintan Formation (Late Triassic). The complete fossil plant collection from Bintan includes specimens from four localities, all of which were examined for the first time in this study. Twenty-one taxa were determined, compared to an earlier four, and three earlier determinations were revised. Of these 21 taxa, 14 were attributed to the Bennettitales, including eleven leaf species, one Williamsonia sp., and two other fertile and stem organs. The other components of the flora were limited to twigs and cones of Brachyphyllum sp., leaves of Podozamites sp. and leaves of Nilssonia sp., in addition to some unusually large seeds. The Bintan Flora is exceptional compared to southeast Asian Late Triassic floras because of the complete absence of fern and sphenophyte remains, and the dominance of diminutive Pterophyllum and Ptilophyllum leaves. Since the Bintan flora lacks riparian elements, these differences are attributed to effects of taphonomy. Further, the similarities between the Bintan and southwest Asian floras support earlier palaeogeographical reconstructions for the Late Triassic.