[dinosaur] Plesiosaur big red blood cells similar to diving mammals and birds (free pdf)

Ben Creisler
[email protected]

A new paper in open access:

Corinna V. Fleischle, P. Martin Sander, Tanja Wintrich & Kai R. Caspar
(2019)
Hematological convergence between Mesozoic marine reptiles (Sauropterygia)
and extant aquatic amniotes elucidates diving adaptations in plesiosaurs.
PeerJ 7:e8022
doi: https://urldefense.proofpoint.com/v2/url?u=https-3A__doi.org_10.7717_peerj.8022&d=DwIBaQ&c=clK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=Ry_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=IORp41Dr6spdp2_eAL_9pucmACkZzYuZYUAw7rArKgI&s=FQoGocU5d8GEXHyzhZOV-SwEVXqemBF-fHVyIYIayjE&e= 
https://urldefense.proofpoint.com/v2/url?u=https-3A__peerj.com_articles_8022_&d=DwIBaQ&c=clK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=Ry_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=IORp41Dr6spdp2_eAL_9pucmACkZzYuZYUAw7rArKgI&s=aeHmU0bHx2w3sjYz0T0Xoo2kG0GkhIKZAFV_hgGV5to&e= 

Free pdf:
https://urldefense.proofpoint.com/v2/url?u=https-3A__peerj.com_articles_8022.pdf&d=DwIBaQ&c=clK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=Ry_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=IORp41Dr6spdp2_eAL_9pucmACkZzYuZYUAw7rArKgI&s=eaQb5hZgVKmcIqKlgxT5D6zrhGoCqEvrNpF-DtBslD4&e= 


Plesiosaurs are a prominent group of Mesozoic marine reptiles, belonging to
the more inclusive clades Pistosauroidea and Sauropterygia. In the Middle
Triassic, the early pistosauroid ancestors of plesiosaurs left their
ancestral coastal habitats and increasingly adapted to a life in the open
ocean. This ecological shift was accompanied by profound changes in
locomotion, sensory ecology and metabolism. However, investigations of
physiological adaptations on the cellular level related to the pelagic
lifestyle are lacking so far. Using vascular canal diameter, derived from
osteohistological thin-sections, we show that inferred red blood cell size
significantly increases in pistosauroids compared to more basal
sauropterygians. This change appears to have occurred in conjunction with
the dispersal to open marine environments, with cell size remaining
consistently large in plesiosaurs. Enlarged red blood cells likely
represent an adaptation of plesiosaurs repeated deep dives in the pelagic
habitat and mirror conditions found in extant marine mammals and birds. Our
results emphasize physiological aspects of adaptive convergence among
fossil and extant marine amniotes and add to our current understanding of
plesiosaur evolution.