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[dinosaur] Sequiwaimanu + Russian turtles and mosasaurs + Oligocene sea turtle from South America

Ben Creisler

Some recent papers and a relatively recent book:

Sequiwaimanu rosieae, n. gen. et sp.

Gerald Mayr, Vanesa L. De Pietri, Leigh Love, Al A. Mannering & R. Paul Scofield (2018)
A well-preserved new mid-paleocene penguin (Aves, Sphenisciformes) from the Waipara Greensand in New Zealand.
Journal of Vertebrate Paleontology Article: e1398169Â
DOI: 10.1080/02724634.2017.1398169

We describe a partial skeleton of a new stem group representative of the Sphenisciformes from the mid-Paleocene Waipara Greensand in New Zealand, which represents the best-preserved and most complete Paleocene penguin found so far. Sequiwaimanu rosieae, n. gen. et sp., is the fourth penguin species from the Waipara Greensand, which previously yielded two species that were assigned to the taxon Waimanu, in addition to leg bones of an unnamed giant penguin. Among other features, the new species is characterized by an articular facet for the furcula on the apex carinae of the sternum, which is unknown from other sphenisciforms. We perform detailed comparisons with the species assigned to Waimanu and show that the type species Waimanu manneringi differs in tarsometatarsus morphology from its putative congener âW.â tuatahi, which is here assigned to the new taxon Muriwaimanu. Sequiwaimanu rosieae exhibits a more derived morphology than Muriwaimanu tuatahi, but its exact affinities to W. manneringi are unresolved owing to the incompletely known osteology of the latter species. With S. rosieae being more closely related to the crown group than M. tuatahi, shared characteristics of the two taxa are likely to be plesiomorphic for sphenisciforms. Although the skeletal morphology of these sphenisciform stem species shows some similarities to plotopterids (i.e., wing-propelled diving seabirds from the North Pacific Basin) in some characters, the stem group sphenisciforms from the Waipara Greensand are clearly distinguished from plotopterids.


A recently available book in Russian not yet mentioned (covers turtles and mosasaurs):

Free pdf:

A.V. Lopatin and N.V. Zelenkov (editors) (2015)
Fossil Reptiles and Birds Part 4
Fossil Vertebrates of Russia and Adjacent Countries
Moscow GEOS pp. 397
ISBN: 978-5-89118-696-5


Free pdf:

Cadena E, Abella J, Gregori M. (2018)Â
The first Paleogene (Oligocene) sea turtle record of South America.Â
PeerJ Preprints 6:e26532v1
doi:Â https://doi.org/10.7287/peerj.preprints.26532v1

The evolution and occurrence of fossil sea turtles at the Pacific margin of South America is poorly known and restricted to Neogene (Miocene) findings from PerÃ. Here we report and describe the first record of Paleogene (Late Oligocene, ~24 Ma) sea turtle remains. The fossil material corresponds to a single, isolated and well-preserved costal bone found at the MontaÃita/OlÃn locality, Santa Elena Province, Ecuador. Comparisons with other Oligocene and extant representatives allow us to confirm that belong to a sea turtle characterized by: lack of lateral ossification, allowing the dorsal exposure of the distal end of ribs; dorsal surface of bone sculptured, changing from dense vermiculation at the vertebral scute region and changing to anastomosing pattern of grooves at the most lateral portion of the costal. This fossil finding shows the high potential that the Ecuadorian Paleogene outcrops have in order to explore the evolution and paleobiogeography distribution of sea turtles by the time that the Pacific and the Atlantic oceans were connected via the Panama basin.


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