[dinosaur] Dolichosaurs (Cretaceous ophidiomorph aquatic lizards) geographical distribution (free pdf)

Ben Creisler
[email protected]

Now out in full form (was only an abstract) with free pdf:

Michelle Campbell Mekarski, Stephanie E. Pierce and Michael W. Caldwell
(2019)
Spatiotemporal Distributions of Non-ophidian Ophidiomorphs, With
Implications for Their Origin, Radiation, and Extinction.
Frontiers in Earth Science 7:245
doi: https://urldefense.proofpoint.com/v2/url?u=https-3A__doi.org_10.3389_feart.2019.00245&d=DwIFaQ&c=clK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=Ry_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=3aAxzW90MT0WkAfUuIzFurarrQBK7l7ZGE0AbIfDi7o&s=xemckoSE8SgGRabEU3O7o7vxtCQ72snhv9_bEUw3eek&e= 
https://urldefense.proofpoint.com/v2/url?u=https-3A__www.frontiersin.org_articles_10.3389_feart.2019.00245_full&d=DwIFaQ&c=clK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=Ry_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=3aAxzW90MT0WkAfUuIzFurarrQBK7l7ZGE0AbIfDi7o&s=r0jlw7kS_0oCfWm3I0gEeKBMVMIb5uTPI1-0cWOJDb4&e= 


Non-ophidian ophidiomorphs, colloquially referred to as 'dolichosaurs,' are
small-bodied aquatic lizards that lived in shallow seaways, rivers, and
reef environments during the Late Cretaceous. Preservational, geographic,
and taphonomic biases in this group make trends in biodiversity difficult
to assess. This is exemplified by the fact that the majority of the
described species are monotypic and known only from single specimens,
imparting very little information on morphological or spatial variation.
Here we present a revision of the spatial and temporal distributions of
non-ophidian ophidiomorph lizards ('dolichosaurs') from Cretaceous
sediments worldwide. The fossil record of dolichosaurs begins in the
Valanginian (Early Cretaceous). The late Early Cretaceous records are
sparse but suggest a wide geographic distribution spanning the Tethys and
Western Pacific. This is followed by a dense Cenomanian record from Tethyan
and British deposits, and rarer specimens from North America. Though there
is a substantial drop in the number of specimens recorded from the
Turonian–Maastrichtian, these rare occurrences represent the largest
geographical distribution of dolichosaurs: spanning Europe, North America,
and South America before going extinct during the end-Cretaceous mass
extinction. These occurrences indicate that ophidiomorphs most likely
originated in the Jurassic Tethys and continued to radiate spatially and
phylogenetically until the end of the Mesozoic, showing much more
temporally and environmentally diverse patterns than previously indicated.