The Triassic genus Telemachus: paleobiology and evolutionary significance of an enigmatic conifer

ESCAPA, IGNACIO; DECOMBEIX, ANNE-LAURE; TAYLOR, EDITH L.

Mar del Plata

Simposio; XIV Simposio Argentino de Paleobotanica y Palinologia; 2009

Universidad Nacional de Mar del Plata

The seed cones classically included in the genus Telemachus probably represent the conifer with the widest distribution in the Triassic of Gondwana. Evidence from different localities suggests that Telemachus and the leaves Heidiphyllum were produced by the same plant, and could be related with numerous Triassic conifers that also bear multiveined leaves. The systematic affinities of Telemachus remain unclear and the genus has been alternatively related with different conifer families (e.g., Podocarpaceae, Voltziaceae) based on particular features such as the presence of several ovuliferous scale lobes, the partial fusion of bract and scale, or the associated, multiveined leaves. The present contribution is based on a sample of 50 compressed cones collected in the Lashly Formation (Upper Triassic) of the Allan Hills, Southern Victoria Land, Antarctica. Different techniques were used to extract the data from the cones, which allowed a better understanding of its paleobiology and relationships with other so-called transitional conifers. A morphological phylogenetic study including Telemachus and additional Paleozoic and Mesozoic conifers was carried out, showing the highly homoplastic condition of some of the characters classically used in conifer systematics. Exceptionally preserved compressions of Telemachus show anatomical features, allowing for comparisons with Triassic permineralized taxa from Antarctica such as Parasciadopitys ovulate cones, Leastrobus pollen cones, and Notophytum stems. In this context, the evidence suggests that all of these taxa may constitute part of the same plant, which could shed light on the origin of some post-Triassic conifer families.