Abstract Detail

Recent Topics Posters

Andruchow Colombo, Ana [1], Gandolfo, Maria [2], Cuneo, N. Ruben [3], Escapa, Ignacio [4].

Ginkgoaleans at the edge of the Mesozoic: Ginkgoites from the Late Cretaceous Lefipán Formation of Patagonia, Argentina.

The ginkgophytes are today represented by the single “living fossil” species Ginkgo biloba L., which is naturally distributed in China and cultivated worldwide. However, the ginkgophyte lineage shows an extensive fossil record going back to the Paleozoic of both hemispheres. In South America, they have a fairly continuous record beginning in the late Paleozoic, throughout most of the Mesozoic, and reaching the early Eocene. Such record includes both vegetative and reproductive remains. The Cretaceous macrofossil record of this group in South America is restricted to Lower Cretaceous sediments, where it is relatively abundant. However, to our knowledge, no macrofossils have been described for the Late Cretaceous and early Paleogene of the continent yet. Here, we present fossils assigned to the form-genus Ginkgoites Seward, collected from the Maastrichtian (uppermost Cretaceous) sediments of the Lefipán Formation (Chubut Province, Patagonia, Argentina). The studied material consists of three specimens preserved as impressions and compressions of isolated, flabellate, and petiolate (Ginkgo-like) leaves. One of the specimens has attached fragmentary cuticular remains, showing its epidermal cell arrangement and morphology. A second specimen shows evidence of insect damage, which based on its size and morphology is consistent with hole feeding. As it was extensively discussed in literature, Ginkgo-like leaves are common among different lineages within the ginkgophytes, having been associated, at least, to three different families. Therefore, this type of leaves does not provide sufficient information to assign the fossil specimens to a natural genus or family. In this context, and due to the lack of record of ginkgoalean reproductive structures in the Lefipán sediments, we assign the new Patagonian fossils to the form-genus Ginkgoites, erected to encompass leaves identical to those of Ginkgo, and within an insertae sedis family. These fossils constitute the first Late Cretaceous record from Argentina and South America for the ginkgophytes, completing the mentioned gap for the Cretaceous of the continent.

1 - Cornell University, Plant Biology Section, 512 Mann Library, Ithaca, NY, 14853, USA
2 - Cornell University, L. H. Bailey Hortorium, Plant Biology Section, SIPS, 406 Mann Library Building, Plant Biology Section, Ithaca, NY, 14853, United States
3 - MEF, Av. Fontana 140, Trelew-Chubut, U, 9100, Argentina
4 - MEF-CONICET, Fontana 140, Trelew Chubut, U, 9100, Argentina

Keywords:
Ginkgo
Ginkgoites
Ginkgoales
Ginkgophytes
Lefipán Formation
Maastrichtian
Late Cretaceous
Patagonia
Argentina.

Presentation Type: Recent Topics Poster
Session: P1, Recent Topics Posters
Location: Virtual/Virtual
Date: Thursday, July 22nd, 2021
Time: 5:00 PM(EDT)
Number: P1RT025
Abstract ID:1415
Candidate for Awards:None