Fossil seed cones of Pinus L. (sect. Pinus, subsect. Pinaster LOUDON, Sula group) from the late Neogene and early Pleistocene of Europe
Abstrakt
European late Neogene to early Pleistocene seed cones and seeds similar to those of the modern species of Pinus roxburghii Sarg. in the Himalayas and Pinus canariensis C. Sm. on the Canary Islands are treated in detail.
Material obtained from various collections in Italy, Greece, Germany and France was evaluated with the aim to find diagnostic traits that may help to distinguish taxa within the studied fossil records. On the basis of subtile differences in morphology of seed cone apophyses the four populations studied were assigned either to Pinus strozzii Gaudin (apophyses on convex side conical to pyramidal, edged - records from Tuscany in Italy and Rhodes in Greece) or Pinus timleri Kinkelin (apophyses cylindrical to hemispherical, apically rounded - records from Rhineland in Germany and Gascony in France).
The independent status of both species is also maintained because they occurred in isolated areas in the eastern and central Mediterranean vs. western Europe. Both closely related species assume an intermediate position between the two related extant species assigned to the informal Sula group (former subgen.
Pinus sect. Sula or sect.
Pinus subsect. Canarienses Loudon, recently merged with subsect.
Pinaster Loudon based on molecular phylogeny) and share many morphological traits typical of the Sula group (excentromucronate apophyses with minute mucros and seeds with adnate wings). A statistical evaluation of morphology of apophyses/umbos has been attempted stressing close morphological affinity of the fossil record.
However, limited number of available fossils does not suffice to indicate exact pathways of divergence between both extant species but the record from the Pleistocene of Rhodes is more similar to the highly variable seed cones of Pinus canariensis. Other seed cones from the German and French late Neogene also show the character variations typical of the seed cones of the Himalayan species Pinus roxburghii.