Abstract Detail

Paleobotanical Section

Koppelhus, Eva [1], Coria, Rodolfo [2].

A new record of a species of Osmundaceae from the Upper Cretaceous of James Ross Island, Antarctic Peninsula.

During the 2014 expedition to James Ross Island, palynological and wood samples were collected for further analysis including a rather peculiar looking plant fossil. Although previous palaeobotanical investigations of the Snow Hill Island Formation (Marambio Group) has produced gymnosperms wood, and angiosperms leaves and seeds, nothing like this specimen has been reported to date. It turned out be a new specimen of Millerocaulis a genus belonging to Osmundaceae. The specimen was originally elongated and more than 6 cm long and 3.4 cm wide. It had split in half before it was found and the concave side looks similar to a cone. However, the inside has in the middle a stem from which fibres extend in 45 degrees angle. These seem to appear on the other side as 1mm in diameter tubes closely packed. The fossil is very compact and did not yield much information when studied using a dissecting microscope. Instead, a thin section was made and it turned out to be very informative. It shows an arrangement of several vascular bundles, these are not round but bean shaped and surrounded by parenchyma cells. There are some minerals that are appearing black. In a very small area the cuticle and epidermis are visible. This specimen is the fifth record of Millerocaulis in Antarctica. The first record was from the Triassic in the Transantarctic Mountains where several specimens of Millerocaulis beardmorensis were found (Schopf 1978) The second was from the Late Cretaceous from Williams Point on Livingston Island, South Shetland Islands (Cantrill 1997) The third one was from the Triassic of the Transantartic Mountains Millerocaulis woolfei (Rothwell et al 2002) The fourth was from the Aptian on Livingston Island in the South Shetlands Islands (Vera 2007). The specimen found on James Ross Island appear to be a new species as it has different anatomical characters from the previous described specimens.

1 - University of Alberta, Biological Sciences, 11145 Saskatchewan Drive, Edmonton, AB, T6G 2E9, Canada
2 - Mueo Carmen Funes, Av. Cordoba 55, Plaza Huincul, Neuquen, 8318, Argentina

Keywords:
Osmundaceae
Late Cretaceous
Antarctic Peninsula
Millerocaulis.

Presentation Type: Oral Paper:Papers for Sections
Session: 28
Location: Salon 13/The Shaw Conference Centre
Date: Tuesday, July 28th, 2015
Time: 8:00 AM
Number: 28001
Abstract ID:1208
Candidate for Awards:None