[dinosaur] Karoo cynodont burrow scratch marks + glyptosaurine lizards + night bird evolution

Ben Creisler
[email protected]

Some recent non-dino papers:


Emese M. Bordy, Orsolya Sztanó, Akhil Rampersadh, John Almond & Jonah N.
Choiniere (2019)
Vertebrate scratch traces from the Middle Triassic Burgersdorp Formation of
the main Karoo Basin, South Africa: Sedimentological and ichnological
assessment.
Journal of African Earth Sciences (advance online publication)
doi: https://urldefense.proofpoint.com/v2/url?u=https-3A__doi.org_10.1016_j.jafrearsci.2019.103594&d=DwIFaQ&c=clK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=Ry_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=LAXiDnYTIXs08QPX_Q6aKNm3Ro6Hpm6DoMyKDobu1mc&s=i-Tdf8Yfdn34UOXcvr2UPnB7TzfpkOK6WWNkIra8chY&e= 
https://urldefense.proofpoint.com/v2/url?u=https-3A__www.sciencedirect.com_science_article_pii_S1464343X19302493&d=DwIFaQ&c=clK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=Ry_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=LAXiDnYTIXs08QPX_Q6aKNm3Ro6Hpm6DoMyKDobu1mc&s=L5lST54yBoNHHh0CdOOAzkVploiY2IaIFzX4bDiIB6A&e= 

Highlights

Burrow casts with well-preserved, scratch traces form a complex burrow
network.
The most likely tracemakers of these Karoo burrows are non-mammalian
cynodonts.
Burrowing occurred in crevasse splays adjacent to laterally migrating river
channels.
The 3D burrow network is comparable to pre-Jurassic tetrapod burrows
globally.
The Middle Triassic is key in the evolution of complex vertebrate burrowing.

Abstract

Containing one of the richest late Early to early Middle Triassic
continental biotas globally, the Burgersdorp Formation of the main Karoo
Basin in South Africa hosts a diverse vertebrate fossil assemblage.
Comparatively, trace fossils in this unit are lesser known, and thus how
the Burgersdorp biotas behaved and interacted with their palaeoenvironment
remain enigmatic. Here we report on two Middle Triassic continental
ichnofossil localities dominated by tetrapod scratch traces from the
Anisian part (subzones B and C) of the Burgersdorp Formation in the main
Karoo Basin (Eastern Cape, South Africa). Analyses of the trace fossils and
associated sedimentary facies aim to identify the possible trace makers,
their behaviours and the local depositional conditions in this southern
part of Pangea. We establish the palaeoenvironmental context for the
ichnofossils combining ichnological data with the sedimentological records
of the trace fossil sites and the nearby type area of the Burgersdorp
Formation. To facilitate comparisons with similar trace fossils in the
future, we quantify the morphometric parameters of these Burgersdorp trace
fossils in digital models. Our results show that bilobated, branching and
cross-cutting furrow casts with abundant scratch traces: (a) were generated
within crevasse splay deposits adjacent to laterally migrating river
channels in a semi-arid setting, and (b) can be interpreted as the
claw-scratched ventral walls of a therapsid burrow system with a 3D network
architecture. This well-developed vertebrate burrow network complex from
the Middle Triassic of South Africa is among a handful of similarly complex
vertebrate trace fossils in the global pre-Jurassic ichnological record.
Collectively, these trace fossils indicate that the Triassic, and in
particular the Middle Triassic, was an important period in the evolutionary
history of the complex vertebrate burrowing.

======


Robert M. Sullivan (2019)
The taxonomy, chronostratigraphy and paleobiogeography of glyptosaurine
lizards (Glyptosaurinae, Anguidae).
Comptes Rendus Palevol (advance online publication)
doi: https://urldefense.proofpoint.com/v2/url?u=https-3A__doi.org_10.1016_j.crpv.2019.05.006&d=DwIFaQ&c=clK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=Ry_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=LAXiDnYTIXs08QPX_Q6aKNm3Ro6Hpm6DoMyKDobu1mc&s=_mE0_ZTo3aiG7QXXzf3BtssDFngkRwRr4LUarBchh-s&e= 
https://urldefense.proofpoint.com/v2/url?u=https-3A__www.sciencedirect.com_science_article_abs_pii_S1631068319301228&d=DwIFaQ&c=clK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=Ry_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=LAXiDnYTIXs08QPX_Q6aKNm3Ro6Hpm6DoMyKDobu1mc&s=SKcFk3ryJCbN93pJYqdBv8k4b3WyFLLA2Mk-A_sERWE&e= 


Glyptosaurine lizards (Glyptosaurinae, Anguidae) are an extinct group of
heavily armored lizards known from North America, Europe and Asia.
Glyptosaurine lizards, taxa that possess fully developed tuberculated
dermal armor, appear to have been established in North America by late
early Puercan time (To3). "Proxestops," a taxon distinguished by a
combination of vermiculate and tuberculated osteoderm sculpturing, is
considered to be a non-glyptosaurine, a sister taxon of the Glyptosaurinae.
Known from only fragmentary remains, its wide chronostratigraphic
distribution suggests that "Proxestops" is a form genus that, in all
probability, represents more than one taxon, that ranges from the middle
Paleocene to the early Eocene of North America. Moreover, the taxa
Odaxosaurus piger, Parodaxosaurus sanjuanensis and "Proxestops" are best
considered "proto-glyptosaurines". "Melanosaurins" and glyptosaurins were
well-established by the early Eocene, especially in North America, and are
here documented by their type species and chronostratigraphic levels. Both
tribes are present in Europe (MP7), too, but the record is not as estensive
as that of North America. The North American taxon Gaultia silvaticus (Wa0)
is transitional between a "melanosaurin" and glyptosaurin. Because it lacks
the well-defined hexagonal osteoderms that characterize the Glyptosaurini,
it is removed from that group and considered to be a "melanosaurin". The
"melanosaurin" taxon "Xestops" savagei (Wa4–Wa6) cannot be referred to
Xestops (Br2) based on non-corresponding elements and because superficial
similarity does not justify assignment to this taxon. Arpadosaurus
sepulchralis (Wa6?), whose holotype is a fragmentary right frontal, is
considered a subjective junior synonym of A. gazinorum, based on minor
differences in the epidermal scale pattern that probably represent
individual variation. "Glyptosaurus" agmodon (Wa6?), based on a partial
right maxilla, cannot be referred to Glyptosaurus (sensu stricto), and the
material upon which this taxon is based bears strong resemblance to
material identified as cf. "?Paraglyptosaurus" yatkolai (Wa5–Wa6).
"Glyptosaurus" rhodinos (Wa5) is based on an incomplete parietal, and its
reference to Glyptosaurus is considered problematic. Eoglyptosaurus
donohoei (Wa7) is probably valid and is re-established here. Glyptosaurus
(sensu stricto) is known solely from the middle Eocene (Br2) by G.
sylvestris. Dimetoposaurus wyomingensis (Br3) is removed from Xestops
vagans because its synonymy was based on superficial similarities.
Helodermoides tuberculatus, the largest and last glyptosaurin (Ch3), is
restricted to the Chadronian of North America. Only the "melanosaurin"
Peltosaurus granulosus (Or2–Or3), which includes the species P. abbotti,
seems to have crossed the Eocene-Oligocene boundary, and appears to be
largely restricted to the Orellan, but extended into the Arikareean.
European glyptosaurines are also represented by both glyptosaurins and
"melanosaurins" early in the Eocene (MP7). Placosauriops-like
"melanosaurins" are known from Dormaal (MP7), and the glyptosaurin
taxon?Placosaurus ragei occurs at the same level. "Placosauriops
abderhaldeni" has been identified from the Grube Messel (MP11), but this
assignment remains dubious because the species has not been adequately
diagnosed, and the holotype species is from the Geiseltal (MP13), which is
some 4.5 million years younger. Placosauriops weigelti (MP13) is the only
valid species of this genus. Paraxestops stehlini (MP14) is not referable
to the North American taxon Xestops, and its relationship to Placosauriops
has not been studied. The late Eocene glyptosaurins Placosaurus estesi
(MP17) and P. rugosus (MP18) are the last glyptosaurines known from Europe
and appear to have gone extinct at the Eocene-Oligocene boundary, casulties
perhaps of the "Grande Coupure". Asian glyptosaurines are known solely from
one species, Stenoplacosaurus mongoliensis, from the middle Eocene
(Sharamurunian) of China. Glyptosaurines most likely originated in North
America, diversified by late Paleocene time, and rapidly spread across the
North Atlantic into Europe by the early Eocene. Both "melanosaurins" and
glyptosaurins took a foothold in Europe by the early Neustrian, but the
glyptosaurins, aside from one occurrence (Dormaal, MP7), were conspicuously
absent for most of Neustrian through early Robiacian time. In North
America, glyptosaurins diversified during the early and middle Eocene,
while in Europe small "melanosaurins" were a prominent part of the
paleoherpetofauna, and glyptosaurins are unknown for most of the Neustrian
through the Geiseltalian, in both the fossilferous Lagerstätten of Messel
and Geiseltal. Stenoplacosaurus is the only known glyptosaurin
glyptosaurine from Asia, and its abrupt appearance during the late Eocene
suggests the possiblity of a Beringian dispersal from North America into
Asia.
===

Free pdf:

Albert Chen, Noor D. White, Roger B.J. Benson, Michael J. Braun and Daniel
J. Field (2019)
Total-Evidence Framework Reveals Complex Morphological Evolution in
Nightbirds (Strisores).
Diversity 2019, 11(9), 143
doi: https://urldefense.proofpoint.com/v2/url?u=https-3A__doi.org_10.3390_d11090143&d=DwIFaQ&c=clK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=Ry_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=LAXiDnYTIXs08QPX_Q6aKNm3Ro6Hpm6DoMyKDobu1mc&s=zFZW97AhebhE2XqbtHz7-gjMpJNnfIaJD6KyO8kmm9Y&e= 
https://urldefense.proofpoint.com/v2/url?u=https-3A__www.mdpi.com_1424-2D2818_11_9_143&d=DwIFaQ&c=clK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=Ry_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=LAXiDnYTIXs08QPX_Q6aKNm3Ro6Hpm6DoMyKDobu1mc&s=r3AeT3IgSHx6GCntZE2VNcQza_ya251CpUAORLGA7CQ&e= 

Strisores is a clade of neoavian birds that include diurnal aerial
specialists such as swifts and hummingbirds, as well as several
predominantly nocturnal lineages such as nightjars and potoos. Despite the
use of genome-scale molecular datasets, the phylogenetic interrelationships
among major strisorean groups remain controversial. Given the availability
of next-generation sequence data for Strisores and the clade’s rich fossil
record, we reassessed the phylogeny of Strisores by incorporating a
large-scale sequence dataset with anatomical data from living and fossil
strisoreans within a Bayesian total-evidence framework. Combined analyses
of molecular and morphological data resulted in a phylogenetic topology for
Strisores that is congruent with the findings of two recent molecular
phylogenomic studies, supporting nightjars (Caprimulgidae) as the extant
sister group of the remainder of Strisores. This total-evidence framework
allowed us to identify morphological synapomorphies for strisorean clades
previously recovered using molecular-only datasets. However, a combined
analysis of molecular and morphological data highlighted strong signal
conflict between sequence and anatomical data in Strisores. Furthermore,
simultaneous analysis of molecular and morphological data recovered
differing placements for some fossil taxa compared with analyses of
morphological data under a molecular scaffold, highlighting the importance
of analytical decisions when conducting morphological phylogenetic analyses
of taxa with molecular phylogenetic data. We suggest that multiple
strisorean lineages have experienced convergent evolution across the
skeleton, obfuscating the phylogenetic position of certain fossils, and
that many distinctive specializations of strisorean subclades were acquired
early in their evolutionary history. Despite this apparent complexity in
the evolutionary history of Strisores, our results provide fossil support
for aerial foraging as the ancestral ecological strategy of Strisores, as
implied by recent phylogenetic topologies derived from molecular data.

===
also

Free pdf:

Christian Püntener, Jérémy Anquetin & Jean-Paul Billon-Bruyat (2019)
New material of "Eurysternidae" (Thalassochelydia, Pan-Cryptodira) from the
Kimmeridgian of the Swiss Jura Mountains.
PaleoRxiv (preprint)
DOI: 10.31233/osf.io/4g3pq
https://urldefense.proofpoint.com/v2/url?u=https-3A__paleorxiv.org_4g3pq_&d=DwIFaQ&c=clK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=Ry_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=LAXiDnYTIXs08QPX_Q6aKNm3Ro6Hpm6DoMyKDobu1mc&s=5IY_zabH4hokxSH7EtP__HTRhlG3UDv3anM1OQB2r4s&e= 

The region of Porrentruy (Swiss Jura Mountains) is known for its rich and
diverse assemblage of Late Jurassic coastal marine turtles
(Thalassochelydia). Dominated by the “Plesiochelyidae”, this assemblage
also includes representatives of the two other thalassochelydian groups,
the “Thalassemydidae” and “Eurysternidae.” In this study, we present new
shell-based material from Porrentruy referable to eurysternids. One
specimen represents a juvenile individual or a relatively small taxon, and
is notably characterized by a well fenestrated plastron exhibiting a wider
than long central plastral fontanelle. Two other specimens are much larger
and possibly represent the largest eurysternids known to date. The fourth
specimen is characterized by a unique plastral morphology otherwise only
known in very small juveniles. This is the first time this unique plastral
morphology is known to persist in an adult or subadult. The new material
described herein represents at least three distinct taxa, all of them
probably new. However, we refrain from naming new species based on this
incomplete material in order to avoid adding confusion to an already
complex taxonomical situation. This study provides new insights into the
great diversity of eurysternids during the Late Jurassic.


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