A new stem turtle from the Middle Jurassic of Scotland: new insights into the evolution and palaeoecology of basal turtles

The discovery of a new stem turtle from the Middle Jurassic (Bathonian) deposits of the Isle of Skye, Scotland, sheds new light on the early evolutionary history of Testudinata. Eileanchelys waldmani gen. et sp. nov. is known from cranial and postcranial material of several individuals and represents the most complete Middle Jurassic turtle described to date, bridging the morphological gap between basal turtles from the Late Triassic–Early Jurassic and crown-group turtles that diversify during the Late Jurassic. A phylogenetic analysis places the new taxon within the stem group of Testudines (crown-group turtles) and suggests a sister-group relationship between E. waldmani and Heckerochelys romani from the Middle Jurassic of Russia. Moreover, E. waldmani also demonstrates that stem turtles were ecologically diverse, as it may represent the earliest known aquatic turtle.

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A new stem turtle from the Middle Jurassic of Scotland: new insights into the evolution and palaeoecology of basal turtles

10.31233/osf.io/qxz7d ◽

2017 ◽

Author(s):

Jérémy Anquetin ◽

Paul M. Barrett ◽

Marc E. H. Jones ◽

Scott Moore-Fay ◽

Susan E. Evans

Keyword(s):

Middle Jurassic ◽

Late Jurassic ◽

Evolutionary History ◽

Sister Group ◽

Late Triassic ◽

Sister Group Relationship ◽

New Taxon ◽

Crown Group ◽

History Of ◽

Isle Of Skye

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The first definitive Middle Jurassic atoposaurid (Crocodylomorpha, Neosuchia), and a discussion on the genus Theriosuchus

10.31233/osf.io/fpbh5 ◽

2017 ◽

Author(s):

Mark T. Young ◽

Jonathan Tennant ◽

Stephen L. Brusatte ◽

Thomas J. Challands ◽

Nicholas C. Fraser ◽

...

Keyword(s):

Middle Jurassic ◽

Late Jurassic ◽

Evolutionary History ◽

Valid Species ◽

Diagnostic Features ◽

Comprehensive Review ◽

History Of ◽

Isle Of Skye ◽

Broad Scale

Atoposaurids were a clade of semiaquatic crocodyliforms known from the Late Jurassic to the latest Cretaceous. Tentative remains from Europe, Morocco, and Madagascar may extend their range into the Middle Jurassic. Here we report the first unambiguous Middle Jurassic (late Bajocian–Bathonian) atoposaurid: an anterior dentary from the Isle of Skye, Scotland, UK. A comprehensive review of atoposaurid specimens demonstrates that this dentary can be referred to Theriosuchus based on several derived characters, and differs from the five previously recognized species within this genus. Despite several diagnostic features, we conservatively refer it to Theriosuchus sp., pending the discovery of more complete material. As the oldest known definitively diagnostic atoposaurid, this discovery indicates that the oldest members of this group were small-bodied, had heterodont dentition, and were most likely widespread components of European faunas. Our review of mandibular and dental features in atoposaurids not only allows us to present a revised diagnosis of Theriosuchus, but also reveals a great amount of variability within this genus, and indicates that there are currently five valid species that can be differentiated by unique combinations of dental characteristics. This variability can be included in future broad-scale cladistics analyses of atoposaurids and closely related crocodyliforms, which promise to help untangle the complicated taxonomy and evolutionary history of Atoposauridae.

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Wood anatomy of the Mascarene Dombeyoideae: Systematic and ecological implications

IAWA Journal ◽

10.1163/22941932-90000073 ◽

2011 ◽

Vol 32 (4) ◽

pp. 493-519 ◽

Cited By ~ 7

Author(s):

Anaïs Boura ◽

Timothée Le Péchon ◽

Romain Thomas

Keyword(s):

Evolutionary History ◽

Wood Anatomy ◽

Sister Group ◽

Biological Data ◽

Sister Group Relationship ◽

Anatomical Features ◽

Ecological Implications ◽

History Of ◽

Mascarene Islands ◽

Almost All

The Dombeyoideae (Malvaceae) are one of the most diversified groups of plants in the Mascarene Islands. Species of Dombeya Cav., Ruizia Cav. and Trochetia DC. are distributed in almost all parts of the archipelago and show a wide diversity in their growth forms. This study provides the first wood anatomical descriptions of 17 out of the 22 Mascarene species of Dombeyoideae. Their wood anatomy is similar to that of previously described species: wide vessels, presence of both apotracheal and paratracheal parenchyma, and storied structure. In addition, we also found a second wood anatomical pattern with narrower vessels, high vessel frequency and thick-walled fibres. The two aforementioned wood patterns are considered in a phylogenetic context and used to trace the evolutionary history of several wood anatomical features. For example, the pseudoscalariform pit arrangement supports a sister group relationship between Trochetia granulata Cordem. and T. blackburniana Bojer ex Baker and may be a new synapomorphy of the genus Trochetia. Finally, wood variability is evaluated in relation to geographic, climatic and biological data. Despite the juvenile nature of some of the specimens studied, we discuss how the habit, but also factors related to humidity, influence the variability observed in the Mascarene Dombeyoideae wood structure.

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Sphenofontis velserae gen. et sp. nov., a new rhynchocephalian from the Late Jurassic of Brunn (Solnhofen Archipelago, southern Germany)

PeerJ ◽

10.7717/peerj.11363 ◽

2021 ◽

Vol 9 ◽

pp. e11363

Author(s):

Andrea Villa ◽

Roel Montie ◽

Martin Röper ◽

Monika Rothgaenger ◽

Oliver W.M. Rauhut

Keyword(s):

Middle Jurassic ◽

Late Jurassic ◽

Wide Distribution ◽

New Taxon ◽

Skeletal Morphology ◽

Southern Germany ◽

Single Well ◽

History Of

The Solnhofen Archipelago is well known for its fossil vertebrates of Late Jurassic age, among which figure numerous rhynchocephalian specimens, representing at least six and up to nine genera. A new taxon, named Sphenofontis velserae gen. et sp. nov., increases rhynchocephalian diversity in the Solnhofen Archipelago and is herein described based on a single, well-preserved specimen originating from the Late Kimmeridgian of the Brunn quarry, near Regensburg. The exquisite preservation of the holotype allowed a detailed description of the animal, revealing a skeletal morphology that includes both plesiomorphic and derived features within rhynchocephalians. Sphenofontis is herein referred to Neosphenodontia and tentatively to sphenodontine sphenodontids. It notably differs from all other rhynchocephalians known from the Jurassic of Europe, showing instead closer resemblance with the Middle Jurassic Cynosphenodon from Mexico and especially the extant Sphenodon. This is evidence for a wide distribution of taxa related to the extant tuatara early in the Mesozoic, and also for the presence of less-specialized rhynchocephalians coexisting with more derived forms during the earliest time in the history of the Solnhofen Archipelago.

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Mesozoic Intracontinental Orogeny in the Tectonic History of the Kolyvan’– Tomsk Folded Zone (Southern Siberia): a Synthesis of Geological Data and results of Apatite Fission Track Analysis

Russian Geology and Geophysics ◽

10.2113/rgg20204172 ◽

2021 ◽

Vol 62 (9) ◽

pp. 1006-1020

Author(s):

F.I. Zhimulev ◽

E.V. Vetrov ◽

I.S. Novikov ◽

G. Van Ranst ◽

S. Nachtergaele ◽

...

Keyword(s):

Early Cretaceous ◽

Middle Jurassic ◽

Late Jurassic ◽

Fission Track ◽

Early Jurassic ◽

Late Triassic ◽

Apatite Fission Track ◽

History Of ◽

Paleozoic Rocks ◽

Orogenic Events

Abstract —The Kolyvan’–Tomsk folded zone (KTFZ) is a late Permian collisional orogen in the northwestern section of the Central Asian Orogenic Belt. The Mesozoic history of the KTFZ area includes Late Triassic–Early Jurassic and Late Jurassic–Early Cretaceous orogenic events. The earlier event produced narrow deep half-ramp basins filled with Early–Middle Jurassic molasse south of the KTFZ, and the later activity rejuvenated the Tomsk thrust fault, whereby the KTFZ Paleozoic rocks were thrust over the Early–Middle Jurassic basin sediments. The Mesozoic orogenic events induced erosion and the ensuing exposure of granitoids (Barlak complex) that were emplaced in a within-plate context after the Permian collisional orogeny. Both events were most likely associated with ocean closure, i.e., the Paleothetys Ocean in the Late Triassic–Early Jurassic and the Mongol–Okhotsk Ocean in the Late Jurassic–Early Cretaceous. The apatite fission track (AFT) ages of granitoids from the Ob’ complex in the KTFZ range between ~120 and 100 Ma (the Aptian and the Albian). The rocks with Early Cretaceous AFT ages were exhumed as a result of denudation and peneplanation of the Early Cretaceous orogeny, which produced a vast Late Cretaceous–Paleogene planation surface. The tectonic pattern of the two orogenic events, although being different in details, generally inherited the late Paleozoic primary collisional structure of the Kolyvan’–Tomsk zone.

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A phylogeny of Plesiosauria (Sauropterygia) and its bearing on the systematic status of Leptocleidus Andrews, 1922

Zootaxa ◽

10.11646/zootaxa.1863.1.1 ◽

2008 ◽

Vol 1863 (1) ◽

pp. 1 ◽

Cited By ~ 74

Author(s):

PATRICK S. DRUCKENMILLER ◽

ANTHONY P. RUSSELL

Keyword(s):

Late Jurassic ◽

Cladistic Analysis ◽

Sister Group ◽

Phylogenetic Position ◽

Sister Group Relationship ◽

New Taxon ◽

Short Neck ◽

Operational Taxonomic Units ◽

Phylogenetic Hypotheses ◽

The Uk

Leptocleidus Andrews, 1922 is a poorly known plesiosaur genus from Lower Cretaceous successions of the UK, South Africa, and Australia. Historically, there has been little consensus regarding its phylogenetic position within Plesiosauria, largely because of its seemingly aberrant combination of a relatively small skull and short neck. As a result, a diverse array of potential sister groups have been posited for Leptocleidus, including long-necked Cretaceous elasmosaurids, Early Jurassic “rhomaleosaurs”, and Middle to Late Jurassic pliosaurids. A cladistic analysis including Leptocleidus, and a new, apparently morphologically similar specimen from Alberta, TMP 94.122.01, was undertaken to assess their phylogenetic position within Plesiosauria. A character-taxon matrix was assembled afresh, consisting of 33 operational taxonomic units sampled broadly among plesiosaurs. 185 cranial and postcranial characters used in plesiosaur phylogenetics were critically reanalyzed, of which 152 were employed in the parsimony analysis. The results indicate a basal dichotomous split into the traditionally recognized pliosauroid and plesiosauroid clades. Nested within Pliosauroidea, a monophyletic Leptocleididae was recovered, consisting of L. superstes Andrews, 1922 and L. capensis (Andrews, 1911a). In contrast to earlier suggestions, Leptocleidus neither clusters with Rhomaleosaurus, which was found to be paraphyletic, nor with large-skulled pliosaurid taxa, such as Simolestes. Rather, a sister group relationship between Cretaceous Polycotylidae and Leptocleididae was recovered, which is here named Leptocleidoidea. Although TMP 94.122.01 is superficially similar to Leptocleidus, several discrete characters of the skull nest this new taxon within Polycotylidae. Compared to other phylogenetic hypotheses of plesiosaurs, these results are more congruent with respect to the stratigraphic distribution of leptocleidoids. A classification for Plesiosauria is presented.

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Probable basal allosauroid from the early Middle Jurassic Cañadón Asfalto Formation of Argentina highlights phylogenetic uncertainty in tetanuran theropod dinosaurs

Scientific Reports ◽

10.1038/s41598-019-53672-7 ◽

2019 ◽

Vol 9 (1) ◽

Cited By ~ 5

Author(s):

Oliver W. M. Rauhut ◽

Diego Pol

Keyword(s):

Middle Jurassic ◽

Late Jurassic ◽

Evolutionary History ◽

Morphological Evolution ◽

New Taxon ◽

Rapid Radiation ◽

Theropod Dinosaurs ◽

Extinction Event ◽

The Common ◽

Early Radiation

AbstractTetanurae, the most successful clade of theropod dinosaurs, including modern birds, split into three major clades early in their evolutionary history: Megalosauroidea, Coelurosauria, and Allosauroidea. The oldest tetanurans occur in the earliest Middle Jurassic, but the early fossil record of the clade is still poor. Here we report one of the oldest known and most complete pre-Late Jurassic tetanuran, the probable allosauroid Asfaltovenator vialidadi gen. et sp. nov., which has an unusual character combination, uniting features currently considered to be apomorphic of different tetanuran lineages. A phylogenetic analysis resulted in a monophyletic Carnosauria (Allosauroidea + Megalosauroidea), and the inclusion of the new taxon significantly changes topology within carnosaurs. The analysis shows concentrated homoplasy in proximal nodes at the base of Tetanurae, and a temporal peak at the Pliensbachian-Toarcian extinction event, recently identified as a potential driver of tetanuran radiation. These results highlight the complex morphological evolution in the early radiation of tetanuran theropods, in which convergences and parallelisms were extremely common. This pattern seems to be a common feature in rapid radiation events of major clades of vertebrates and might explain the common difficulties to unravel phylogenetic relationships of important lineages at the base of major clades.

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Paleogenomics illuminates the evolutionary history of the extinct Holocene “horned” crocodile of Madagascar, Voay robustus

Communications Biology ◽

10.1038/s42003-021-02017-0 ◽

2021 ◽

Vol 4 (1) ◽

Author(s):

E. Hekkala ◽

J. Gatesy ◽

A. Narechania ◽

R. Meredith ◽

M. Russello ◽

...

Keyword(s):

Ancient Dna ◽

Evolutionary History ◽

Phylogenetic Analyses ◽

Sister Group ◽

Molecular Data ◽

Sister Group Relationship ◽

Molecular Fossil ◽

Close Relationship ◽

History Of ◽

Competing Hypotheses

AbstractAncient DNA is transforming our ability to reconstruct historical patterns and mechanisms shaping modern diversity and distributions. In particular, molecular data from extinct Holocene island faunas have revealed surprising biogeographic scenarios. Here, we recovered partial mitochondrial (mt) genomes for 1300–1400 year old specimens (n = 2) of the extinct “horned” crocodile, Voay robustus, collected from Holocene deposits in southwestern Madagascar. Phylogenetic analyses of partial mt genomes and tip-dated timetrees based on molecular, fossil, and stratigraphic data favor a sister group relationship between Voay and Crocodylus (true crocodiles). These well supported trees conflict with recent morphological systematic work that has consistently placed Voay within Osteolaeminae (dwarf crocodiles and kin) and provide evidence for likely homoplasy in crocodylian cranial anatomy and snout shape. The close relationship between Voay and Crocodylus lends additional context for understanding the biogeographic origins of these genera and refines competing hypotheses for the recent extinction of Voay from Madagascar.

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A basal thunnosaurian from Iraq reveals disparate phylogenetic origins for Cretaceous ichthyosaurs

Biology Letters ◽

10.1098/rsbl.2013.0021 ◽

2013 ◽

Vol 9 (4) ◽

pp. 20130021 ◽

Cited By ~ 38

Author(s):

Valentin Fischer ◽

Robert M. Appleby ◽

Darren Naish ◽

Jeff Liston ◽

James B. Riding ◽

...

Keyword(s):

Middle East ◽

Early Cretaceous ◽

Late Jurassic ◽

Evolutionary History ◽

Early Jurassic ◽

Late Triassic ◽

Low Diversity ◽

History Of

Cretaceous ichthyosaurs have typically been considered a small, homogeneous assemblage sharing a common Late Jurassic ancestor. Their low diversity and disparity have been interpreted as indicative of a decline leading to their Cenomanian extinction. We describe the first post-Triassic ichthyosaur from the Middle East, Malawania anachronus gen. et sp. nov. from the Early Cretaceous of Iraq, and re-evaluate the evolutionary history of parvipelvian ichthyosaurs via phylogenetic and cladogenesis rate analyses. Malawania represents a basal grade in thunnosaurian evolution that arose during a major Late Triassic radiation event and was previously thought to have gone extinct during the Early Jurassic. Its pectoral morphology appears surprisingly archaic, retaining a forefin architecture similar to that of its Early Jurassic relatives. After the initial latest Triassic radiation of early thunnosaurians, two subsequent large radiations produced lineages with Cretaceous representatives, but the radiation events themselves are pre-Cretaceous. Cretaceous ichthyosaurs therefore include distantly related lineages, with contrasting evolutionary histories, and appear more diverse and disparate than previously supposed.

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The first metriorhynchoid crocodyliform from the Aalenian (Middle Jurassic) of Germany, with implications for the evolution of Metriorhynchoidea

Zoological Journal of the Linnean Society ◽

10.1093/zoolinnean/zlz072 ◽

2019 ◽

Author(s):

Manuela Aiglstorfer ◽

Philipe Havlik ◽

Yanina Herrera

Keyword(s):

Middle Jurassic ◽

Evolutionary History ◽

Marine Ecosystems ◽

Morphological Features ◽

New Taxon ◽

Unique Combination ◽

Southern Germany ◽

Puzzle Piece ◽

Character Distribution ◽

History Of

Abstract Thalattosuchia, a clade of Mesozoic aquatic crocodyliforms, were the only archosaurs that ever became fully adapted to marine ecosystems. They are represented by two clades, the semiaquatic teleosauroids and the metriorhynchoids, which include fully pelagic forms. So far, little is known on the early evolutionary history of Metriorhynchoidea and data are sparse, especially from the early Middle Jurassic. Opisuchus meieri gen. et sp. nov. a metriorhynchoid crocodyliform from the early Aalenian (early Middle Jurassic) of southern Germany, is described here. It is one of the most complete specimens of a non-metriorhynchid metriorhynchoid, and the best-preserved thalattosuchian described from the Aalenian. The new taxon is represented by a nearly complete skull, which has a unique combination of characters distinguishing it from other species of Metriorhynchoidea. It displays a mosaic of plesiomorphic and apomorphic morphological features that sheds new light on early metriorhynchoid evolution. This taxon is an important puzzle piece, which will help to better track the mosaic character distribution in Thalattosuchia.

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