Format: ORAL

Andrew C Rozefelds1

1. Queensland Museum, Collection and Research Centre, Hendra, Queensland, 4011, Australia

Fruits composed of a many individual fruitlets that are united into a complex structure are described as a syncarpium or a sorosus. Syncarpia occur in diverse and phylogenetically unrelated families, such as in the monocots Araceae, Bromeliaceae, Cyclanthaceae, Pandanaceae, and dicots Balanophoraceae, Bataceae, Chloranthaceae, Cornaceae, Moraceae, Rafflesiaceae, Rubiaceae and Urticaceae. Permineralised fruits from the Oligocene Capella locality in Queensland consists of many fruitlets, and the seeds occur in the upper portion of each fruitlet. The fruitlets form connate radiating segments, which are interpreted as being derived from the perianth. These radiating segments extend from the centre to the margin of the fruit and adjacent perianth apices appear to be fused apically, forming an irregular pentagonal-hexagonal imbricate surface which shows no consistent phyllotactic pattern. It was possible to exclude the monocot families and Balanophoraceae because the arrangement of seeds in the fruits of these families typically exhibit a regular phyllotaxy, which is less evident in the Pandanaceae. The structure of the fruit and seed shape in the fossil differs from that in Rafflesiaceae. The fossil also has a complex internal structure consisting of thin connate radiating elements that are closely aligned and in this respect the fossils differ from the internal fruit morphology of Cornaceae, Chloranthaceae, Rubiaceae, Bataceae and Urticaceae. Comparison of character traits across these families suggests that these fossil syncarpous fruits are considered to have affinities with the Moraceae. While most fruits in Moraceae are syncarpous the fruit morphology of genera in the family is highly diverse, although five-sided fruits are not currently known. The connately arranged fruitlets and pentagonal-hexagonal external appearance suggests that the closest affinities of these fossils lie with the Artocarpeae.