Modern reef fish after K-Pg extinction (free pdf) + other non-dino papers

[Ben Creisler <bcreisler@gmail.com>]

From: Ben Creisler
bcreisler@gmail.com

A number of recent non-dino papers that may be of interest:

in open access:

S. A. Price, L. Schmitz, C. E. Oufiero, R. I. Eytan, A. Dornburg, W.
L. Smith, M. Friedman, T. J. Near and P. C. Wainwright (2014)
Two waves of colonization straddling the K-Pg boundary formed the
modern reef fish fauna.
Proceedings fo the Royal Soceity B. 281(1783) 20140321
doi: 10.1098/rspb.2014.0321
http://rspb.royalsocietypublishing.org/content/281/1783/20140321.abstract


Living reef fishes are one of the most diverse vertebrate assemblages
on Earth. Despite its prominence and ecological importance, the
origins and assembly of the reef fish fauna is poorly described. A
patchy fossil record suggests that the major colonization of reef
habitats must have occurred in the Late Cretaceous and early
Palaeogene, with the earliest known modern fossil coral reef fish
assemblage dated to 50 Ma. Using a phylogenetic approach, we analysed
the early evolutionary dynamics of modern reef fishes. We find that
reef lineages successively colonized reef habitats throughout the Late
Cretaceous and early Palaeogene. Two waves of invasion were
accompanied by increasing morphological convergence: one in the Late
Cretaceous from 90 to 72 Ma and the other immediately following the
end-Cretaceous mass extinction. The surge in reef invasions after the
Cretaceous-Palaeogene boundary continued for 10 Myr, after which the
pace of transitions to reef habitats slowed. Combined, these patterns
match a classic niche-filling scenario: early transitions to reefs
were made rapidly by morphologically distinct lineages and were
followed by a decrease in the rate of invasions and eventual
saturation of morphospace. Major alterations in reef composition,
distribution and abundance, along with shifts in climate and oceanic
currents, occurred during the Late Cretaceous and early Palaeogene
interval. A causal mechanism between these changes and concurrent
episodes of reef invasion remains obscure, but what is clear is that
the broad framework of the modern reef fish fauna was in place within
10 Myr of the end-Cretaceous extinction.

===


Andrea Cau, Mattia A. Baiano & Pasquale Raia (2014)
A new sphenodontian (Reptilia, Lepidosauria) from the Lower Cretaceous
of Southern Italy and the phylogenetic affinities of the Pietraroia
Plattenkalk rhynchocephalians.
Cretaceous Research 49: 172-180
http://dx.doi.org/10.1016/j.cretres.2014.02.001
http://www.sciencedirect.com/science/article/pii/S0195667114000081

The Pietraroia Plattenkalk (Albian, Lower Cretaceous) of Southern
Italy is known for well-preserved fossil vertebrates, including the
rhynchocephalian lepidosaur Derasmosaurus pietraroiae. A previously
described Pietraroian rhynchocephalian differs from Derasmosaurus in
vertebral, pelvic and foot morphology. A third Pietraroian
rhynchocephalian is described for the first time. The new specimen is
smaller and more gracile than the other Pietraroian rhynchocephalians,
shows a broad unpaired parietal with a small foramen, and robust
dorsal neural spines. Comparison with the ontogenetic series of
Sphenodon suggests that small body size and relatively broad parietal
in the new rhynchocephalian indicate immaturity, although the complete
obliteration of the interparietal suture and the relatively small size
of the parietal foramen may support an ontogenetically mature
condition for that specimen. The morphology of the dorsal vertebrae
excludes referral to Derasmosaurus. Phylogenetic analyses placed the
second specimen among the basal branch of Opisthodontia, and the third
specimen and Derasmosaurus among Sphenodontinae. The phylogenetic
reconstruction supports the interpretation of the Pietraroian
rhynchocephalians as late-surviving members of Jurassic lineages.

==


James F. Parham, Rodrigo A. Otero & Mario E. Suárez (2014)
A sea turtle skull from the Cretaceous of Chile with comments on the
taxonomy and biogeography of Euclastes (formerly Osteopygis).
Cretaceous Research 49: 181-189
http://dx.doi.org/10.1016/j.cretres.2014.03.004
http://www.sciencedirect.com/science/article/pii/S0195667114000445


The taxonomic status of turtle specimens from the Upper Cretaceous
(upper Maastrichtian) Quiriquina Formation of Chile is unresolved. The
previously described specimens were considered either stem-cheloniid
sea turtles or baenids (a freshwater clade otherwise restricted to
North America). A third specimen, a skull described here, supports
previous report that stem-cheloniid sea turtles are present in the
Quiriquina Formation. The new skull is referred to the stem-cheloniid
genus Euclastes (formerly Osteopygis), but not assigned to a species
because the alpha taxonomy is complicated by lingering confusion about
the taxonomic status of a previously described skull from the
Quiriquina Formation (the holotype of Australobaena chilensis).
Revisions to the higher-level taxonomy of durophagous stem cheloniids,
combined with the specimen described here, and other new material from
Gondwana, reveal an emerging pattern of Euclastes biogeography and
stratigraphic distribution. According to current data, Euclastes is
one of the first stem cheloniids found outside the Western Interior
Seaway, dominates Maastrichtian stem-cheloniid localities, crosses the
K/Pg boundary, and eventually goes extinct at the end of the Paleocene
as the stem-cheloniid radiation accelerates in the Paleogene.
==