SVP 2021 abstracts – 29: Falcatakely, yet another misfit from the Maevarano Formation of Late Cretaceous Madagascar

Groenke and O’Connor 2021 report:
“We describe the mechanical and digital preparation of Falcatakely forsterae (UA 10015), a high- and narrowbeaked enantiornithine bird from the Upper Cretaceous Maevarano Formation of Madagascar.”

Not a Late Cretaceous enantiornithine bird, but a VERY basal theropod close to (originally omitted) Late Triassic Tawa (Fig. 1), despite the 160 million year age difference. This makes Falcatakely (Fig. 1) VERY interesting because it represents a hitherto unknown lineage of theropods paralleling birds so much that workers did not realize the difference.

O’Connor et al. 2020 thought Falcatakely was close to the smaller, earlier, toothy and dissimilar enantiornine bird, Pengornis (Fig. 1) after reassembly using µCT scans. As we learned earlier, taxon exclusion was their only mistake. In the large reptile tree (LRT, 1992 taxa) moving Falcatakely from Tawa to Pengornis adds 49 steps.

Groenke and O’Connor continue:
“The preserved rostral and palatal portions of the cranium were remarkably complete given the exceptionally thin bone (<1 mm maxilla thickness), and relatively coarse-grained depositional setting (sandstone). both of these factors made mechanical preparation especially challenging.
Medical-scale computed tomography conducted prior to preparation provided inconclusive resolution as to the anatomical nature of the flattened specimen. Mechanical preparation of the specimen’s surface with insect pins and carbide needles under magnification occurred in two
phases. A subsequent micro-CT scan at Ohio University served as the basis for digital preparation of morphology inaccessible via mechanical preparation, and also for a digital reconstruction.”

The Maevarano Formation of Madagascar
famously preserves a long list of enigma taxa (e.g. Adalatherium, Vintana) and odd representatives of well-established clades (e.g. Masiakasaurus, Rahonavis). So Falcatakely fits right in as yet another misfit.

Falcatakely forsterae
(O’Connor et al. 2020 Late Cretaceous) was originally considered an enantiornithine bird close to a mismatched Pengornis, but here nests with previously omitted Tawa at the base of the Theropoda. Note the tiny premaxillary teeth and lack or loss of an antorbital fenestra in both taxa. This represents a separate lineage of previously unknown theropods evolving into bird-mimics after splitting in the Triassic.

And…
that’s it for the SVP abstracts series. Back to regular daily posts tomorrow. Thank you for your readership.

References
Groenke J and O’Connor P 2021. Preparation and reconstruction of Falcatakely forsterae, an enantiorinithine bird from the Upper Cretaceous Maevarano Formation of Madagascar. Journal of Vertebrate Paleontology abstracts.
O’Connor PM, Turner A H, Groenke JR et al. 2020. Late Cretaceous bird from Madagascar reveals unique development of beaks. Nature. doi:10.1038/s41586-020-2945-x

wiki/Tawa
wiki/Falcatakely