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[dinosaur] Bat flight evolution + dolphin skull shape (free pdfs)





Ben Creisler
bcreisler@gmail.com

Recent (mainly) non-dino stuff that may be of interest...


Free pdf:

Sophia C. Anderson & Graeme D. Ruxton (2020)
The evolution of flight in bats: a novel hypothesis.
Mammal Review (advance online publication)
doi: https://doi.org/10.1111/mam.12211
https://onlinelibrary.wiley.com/doi/10.1111/mam.12211

Free pdf:
https://onlinelibrary.wiley.com/doi/pdf/10.1111/mam.12211


Bats (order Chiroptera) are the only mammals capable of powered flight, and this may be an important factor behind their rapid diversification into the over 1400 species that exist today â around a quarter of all mammalian species. Though flight in bats has been extensively studied, the evolutionary history of the ability to fly in the chiropterans remains unclear.
We provide an updated synthesis of current understanding of the mechanics of flight in bats (from skeleton to metabolism), its relation to echolocation, and where previously articulated evolutionary hypotheses for the development of flight in bats stand following recent empirical advances. We consider the gliding model, and the echolocationâfirst, flightâfirst, tandem development, and diurnal frugivore hypotheses. In the light of the recently published description of the webâwinged dinosaur Ambopteryx longibrachium, we draw together all the current evidence into a novel hypothesis.
We present the interdigital webbing hypothesis: the ancestral bat exhibited interdigital webbing prior to powered flight ability, and the Yangochiroptera, Pteropodidae, and Rhinolophoidea evolved into their current forms along parallel trajectories from this common ancestor. Thus, we suggest that powered flight may have evolved multiple times within the Chiroptera and that similarity in wing morphology in different lineages is driven by convergence from a common ancestor with interdigital webbing.

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Anders Galatius, Rachel Racicot, Michael McGowen & Morten Tange Olsen (2020)
Evolution and diversification of delphinid skull shapes.
iScience 101543
doi: https://doi.org/10.1016/j.isci.2020.101543
https://www.sciencedirect.com/science/article/pii/S2589004220307355


Highlights

Dolphin skull shape is highly dependent on phylogeny
Feeding mode and prey size are primary drivers of the evolution of dolphin skull shapes
Adaptive radiation of skull shapes has been followed by evolutionary stability

Summary

The diversity of the dolphin family was established during a short window of time. We investigated delphinid skull shape evolution, mapping shapes on an up-to-date nuclear phylogeny. In this model, the common ancestor was similar to Lagenorhynchus albirostris. Initial diversification occurred in three directions: towards specialized raptorial feeders of small prey with longer, narrower beaks, e.g., Delphinus; towards wider skulls with downward-oriented rostra and reduced temporal fossae, exemplified by suction feeders, e.g., Globicephala; and towards shorter and wider skulls/rostra and enlarged temporal fossae, e.g., Orcinus. Skull shape diversity was established early, the greatest later developments being adaptation of Steno to raptorial feeding on large prey and the convergence of Pseudorca towards Orcinus, related to handling large prey. Delphinid skull shapes are related to feeding mode and prey size, whereas adaptation to habitat is not marked. Over a short period, delphinid skulls have evolved a diversity eclipsing other extant odontocete clades.

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