scholarly journals A Short-Snouted, Middle Triassic Phytosaur and its Implications for the Morphological Evolution and Biogeography of Phytosauria

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Michelle R. Stocker ◽  
Li-Jun Zhao ◽  
Sterling J. Nesbitt ◽  
Xiao-Chun Wu ◽  
Chun Li
Keyword(s):  
Middle Triassic ◽  
Prey Capture ◽  
General Trend ◽  
Morphological Evolution ◽  
Phylogenetic Analyses ◽  
Late Triassic ◽  
Early Triassic ◽  
Terrestrial Vertebrate ◽  
Nearshore Environments ◽  
Permian Extinction

Abstract Following the end-Permian extinction, terrestrial vertebrate diversity recovered by the Middle Triassic, and that diversity was now dominated by reptiles. However, those reptilian clades, including archosaurs and their closest relatives, are not commonly found until ~30 million years post-extinction in Late Triassic deposits despite time-calibrated phylogenetic analyses predicting an Early Triassic divergence for those clades. One of these groups from the Late Triassic, Phytosauria, is well known from a near-Pangean distribution, and this easily recognized clade bears an elongated rostrum with posteriorly retracted nares and numerous postcranial synapomorphies that are unique compared with all other contemporary reptiles. Here, we recognize the exquisitely preserved, nearly complete skeleton of Diandongosuchus fuyuanensis from the Middle Triassic of China as the oldest and basalmost phytosaur. The Middle Triassic age and lack of the characteristically-elongated rostrum fill a critical morphological and temporal gap in phytosaur evolution, indicating that the characteristic elongated rostrum of phytosaurs appeared subsequent to cranial and postcranial modifications associated with enhanced prey capture, predating that general trend of morphological evolution observed within Crocodyliformes. Additionally, Diandongosuchus supports that the clade was present across Pangea, suggesting early ecosystem exploration for Archosauriformes through nearshore environments and leading to ease of dispersal across the Tethys.

scholarly journals Comparative size evolution of marine clades from the Late Permian through Middle Triassic

Paleobiology ◽  
2015 ◽  
Vol 42 (1) ◽  
pp. 127-142 ◽  
Author(s):  
Ellen K. Schaal ◽  
Matthew E. Clapham ◽  
Brianna L. Rego ◽  
Steve C. Wang ◽  
Jonathan L. Payne
Keyword(s):  
Body Size ◽  
Middle Triassic ◽  
Size Reduction ◽  
Late Triassic ◽  
Early Triassic ◽  
Large Species ◽  
Late Permian ◽  
Triassic Boundary ◽  
Median Size ◽  
Permian Extinction

AbstractThe small size of Early Triassic marine organisms has important implications for the ecological and environmental pressures operating during and after the end-Permian mass extinction. However, this “Lilliput Effect” has only been documented quantitatively in a few invertebrate clades. Moreover, the discovery of Early Triassic gastropod specimens larger than any previously known has called the extent and duration of the Early Triassic size reduction into question. Here, we document and compare Permian-Triassic body size trends globally in eight marine clades (gastropods, bivalves, calcitic and phosphatic brachiopods, ammonoids, ostracods, conodonts, and foraminiferans). Our database contains maximum size measurements for 11,224 specimens and 2,743 species spanning the Late Permian through the Middle to Late Triassic. The Permian/Triassic boundary (PTB) shows more size reduction among species than any other interval. For most higher taxa, maximum and median size among species decreased dramatically from the latest Permian (Changhsingian) to the earliest Triassic (Induan), and then increased during Olenekian (late Early Triassic) and Anisian (early Middle Triassic) time. During the Induan, the only higher taxon much larger than its long-term mean size was the ammonoids; they increased significantly in median size across the PTB, a response perhaps related to their comparatively rapid diversity recovery after the end-Permian extinction. The loss of large species in multiple clades across the PTB resulted from both selective extinction of larger species and evolution of surviving lineages toward smaller sizes. The within-lineage component of size decrease suggests that only part of the size decrease can be related to the end-Permian kill mechanism; in addition, Early Triassic environmental conditions or ecological pressures must have continued to favor small body size as well. After the end-Permian extinction, size decrease occurred across ecologically and physiologically disparate clades, but this size reduction was limited to the first part of the Early Triassic (Induan). Nektonic habitat or physiological buffering capacity may explain the contrast of Early Triassic size increase and diversification in ammonoids versus size reduction and slow recovery in benthic clades.

scholarly journals First record of Mesozoic terrestrial vertebrates from Lithuania: phytosaurs (Diapsida: Archosauriformes) of probable Late Triassic age, with a review of phytosaur biogeography

2012 ◽  
Vol 150 (1) ◽  
pp. 110-122 ◽  
Author(s):  
STEPHEN L. BRUSATTE ◽  
RICHARD J. BUTLER ◽  
GRZEGORZ NIEDŹWIEDZKI ◽  
TOMASZ SULEJ ◽  
ROBERT BRONOWICZ ◽  
...  
Keyword(s):  
North America ◽  
Arid Regions ◽  
First Record ◽  
Upper Triassic ◽  
Late Triassic ◽  
Early Triassic ◽  
Baltic Region ◽  
Terrestrial Vertebrates ◽  
Terrestrial Vertebrate

AbstractFossils of Mesozoic terrestrial vertebrates from Lithuania and the wider East Baltic region of Europe have previously been unknown. We here report the first Mesozoic terrestrial vertebrate fossils from Lithuania: two premaxillary specimens and three teeth that belong to Phytosauria, a common clade of semiaquatic Triassic archosauriforms. These specimens represent an uncrested phytosaur, similar to several species within the generaPaleorhinus,Parasuchus,RutiodonandNicrosaurus. Because phytosaurs are currently only known from the Upper Triassic, their discovery in northwestern Lithuania (the Šaltiškiai clay-pit) suggests that at least part of the Triassic succession in this region is Late Triassic in age, and is not solely Early Triassic as has been previously considered. The new specimens are among the most northerly occurrences of phytosaurs in the Late Triassic, as Lithuania was approximately 7–10° further north than classic phytosaur-bearing localities in nearby Germany and Poland, and as much as 40° further north than the best-sampled phytosaur localities in North America. The far northerly occurrence of the Lithuanian fossils prompts a review of phytosaur biogeography and distribution, which suggests that these predators were widely distributed in the Triassic monsoonal belt but rarer in more arid regions.

scholarly journals Tip dating supports novel resolutions of controversial relationships among early mammals

2020 ◽  
Vol 287 (1928) ◽  
pp. 20200943
Author(s):  
Benedict King ◽  
Robin M. D. Beck
Keyword(s):  
Early Cretaceous ◽  
Late Jurassic ◽  
Morphological Evolution ◽  
Phylogenetic Analyses ◽  
Late Triassic ◽  
Crown Group ◽  
Jehol Biota ◽  
Rates Of Evolution ◽  
Mammal Evolution ◽  
Minimum Divergence

The estimation of the timing of major divergences in early mammal evolution is challenging owing to conflicting interpretations of key fossil taxa. One contentious group is Haramiyida, the earliest members of which are from the Late Triassic. Many phylogenetic analyses have placed haramiyidans in a clade with multituberculates within crown Mammalia, thus extending the minimum divergence date for the crown group deep into the Triassic. A second taxon of interest is the eutherian Juramaia from the Middle–Late Jurassic Yanliao Biota, which is morphologically very similar to eutherians from the Early Cretaceous Jehol Biota and implies a very early origin for therian mammals. Here, we apply Bayesian tip-dated phylogenetic methods to investigate these issues. Tip dating firmly rejects a monophyletic Allotheria (multituberculates and haramiyidans), which are split into three separate clades, a result not found in any previous analysis. Most notably, the Late Triassic Haramiyavia and Thomasia are separate from the Middle Jurassic euharamiyidans. We also test whether the Middle–Late Jurassic age of Juramaia is ‘expected’ given its known morphology by assigning an age prior without hard bounds. Strikingly, this analysis supports an Early Cretaceous age for Juramaia , but similar analyses on 12 other mammaliaforms from the Yanliao Biota return the correct, Jurassic age. Our results show that analyses incorporating stratigraphic data can produce results very different from other methods. Early mammal evolution may have involved multiple instances of convergent morphological evolution (e.g. in the dentition), and tip dating may be a method uniquely suitable to recognizing this owing to the incorporation of stratigraphic data. Our results also confirm that Juramaia is anomalous in exhibiting a much more derived morphology than expected given its age, which in turn implies very high rates of evolution at the base of therian mammals.

Chapter 18 Triassic history

1997 ◽  
Vol 17 (1) ◽  
pp. 340-362 ◽  
Author(s):  
W. Brian Harland ◽  
Isobel Geddes
Keyword(s):  
Middle Triassic ◽  
Early Jurassic ◽  
Late Triassic ◽  
Early Triassic ◽  
Marked Contrast ◽  
Angular Unconformity ◽  
Triassic Period ◽  
Age Determinations

The Triassic Period of about 40 million years dutation spanned about a third of that of the Carboniferous and Permian interval. The Triassic rocks of Svalbard are easily distinguished from the underlying Permian strata because of a distinct desconformity between them and a marked contrast in facies from the resistant. pale coloured, cherls and siliciclastics of the Kapp Starostin Formation to the softer, darker areno-argillaceous Vardebukta and equivalent formations. Figure 18.1 shows the distribution of Triassic strata in Svalbard.The minor angular unconformity represents a hiatus mainly in the Permian rather than the Triassic record. The dominantly argillaceous facies constitute the Early Triassic to Late Middle Triassic Sassendalen Group. The rocks can be well dated from ammonoids, typically within calcareous concretions in the shales.The succeding Kapp Toscana Group is distinguished by a dominatly sandy deltaic facies in which age determinations are difficult. It spans both Late Triassic and Early Jurassic spoehs (roughly mid-Ladinian to mid-Bathonian). The Triassic-Jurassic boundary is not easy to estimate. Nevertheless towards the end of Triassic time (e.g. Rhaetian) the overall scene changed. Thus of the three formations of the Kapp Toscana Group the lower two (Tschermakfjellet and De Geerdalen) belong to the Triassic story. The overlying Wilhelmøya Formation may possibly range from Latest Triassic through Liassic time, and due to its complexity it is also discussed in the Jurassic-Crataceous chapter (19).The facies of the two groups reflect two distinct environmental configurations. The Sassendalen Group was deposited on a distal marine muddy shelf with a

Review of Triassic insects in China

2021 ◽  
pp. SP521-2021-121
Author(s):  
Qianqi Zhang ◽  
Daran Zheng ◽  
Bo Wang ◽  
Haichun Zhang
Keyword(s):  
Yunnan Province ◽  
Middle Triassic ◽  
Southern China ◽  
Northern China ◽  
Guizhou Province ◽  
Late Triassic ◽  
Early Triassic ◽  
Incertae Sedis ◽  
Fossil Records ◽  
Existing Data

AbstractStudies of Triassic insects in China began in 1956, and so far, a total of 89 genera and 109 species have been found from the Triassic of China. The fossil records are from 17 provinces (or regions) in China are assigned to 11 orders except for two genera and species considered incertae sedis in Insecta. These Chinese Triassic insects including one Early Triassic, 53 Middle Triassic and 55 Late Triassic species are briefly reviewed in taxonomy and distribution, and listed here with detailed taxonomic and stratigraphic information. The Middle Triassic Tongchuan Entomofauna and Late Triassic Toksun Entomofauna are introduced much detailed from the perspectives of composition and taxonomy. Existing data indicate that the Chinese Triassic entomofauna is dominated by Hemiptera, Mecoptera and Coleoptera; the Chinese Early Triassic insects are only known from Fuyuan in Yunnan Province, Middle Triassic ones mainly known from northern China and sporadically from Guizhou Province, southern China, and Late Triassic ones widely seen in both northern and southern China; and the Middle and Late Triassic entomofaunas are similar in abundance but show a pattern of “more in northern China than in southern China”.

scholarly journals Middle Triassic (Anisian-Ladinian) Palynomorphs

1985 ◽  
Vol 4 (1) ◽  
pp. 107-111 ◽  
Author(s):  
W. A. Brugman ◽  
J. W. Eggink ◽  
H. Visscher
Keyword(s):  
Middle Triassic ◽  
Late Triassic ◽  
Early Triassic ◽  
Number Of Species ◽  
Deep Wells ◽  
Salt Range ◽  
Similar Development ◽  
Initial Results

Abstract. Initial results of the palynostratigraphical research in the Triassic of northeast Libya indicate the presence of Middle Triassic in several deep-wells. There is some evidence that the uppermost part of the Early Triassic (Late Scythian) as well as the early part of the Late Triassic (Karnian) may also be present. Additional palynological samples will need to be studied to confirm this view.Most Triassic assemblages in northeast Libya show a striking dominance of the monolete lycopodiophytic miospore Aratrisporites; this genus is represented by a large number of species (A. centratus, A. parvispinosus, A. strigosus, A. saturni, A. paenulatus, A. tenuispinosus, A. ovatus). A similar development is known to occur in the Middle Triassic of Australia and Pakistan. Bisaccate pollen is commonly present in the assemblages. Representatives of Triadispora and Lunatisporites are also frequently recorded.On the basis of a few additional forms, two palynologically distinctive intervals may be recognized within the Middle Triassic:Anisian interval. On the basis of Stellapollenites thiergartii, Strotersporites n. sp. of Visscher and Brugman 1981 (not illustrated) and Angustisulcites grandis, an Anisian age for the lower interval is indicated. The latter two species suggest the Early Anisian. The assemblages can be compared with similar assemblages from the Alpine Anisian in Europe (Visscher & Brugman, 1981; Brugman, in prep) and the Salt Range, Pakistan (Brugman & Baud, in prep).Ladinian interval. The upper part of the Libyan Middle Triassic is characterised by the absence of characteristic Anisian elements, and the incoming of rare representatives of the Circumpolles-group . . .

scholarly journals Phylogenetic and ecomorphologic diversifications of spiriferinid brachiopods after the end-Permian extinction

Paleobiology ◽  
2020 ◽  
Vol 46 (4) ◽  
pp. 495-510
Author(s):  
Zhen Guo ◽  
Zhong-Qiang Chen ◽  
David A. T. Harper
Keyword(s):  
Phylogenetic Analysis ◽  
Small Group ◽  
Phylogenetic Trees ◽  
Early Jurassic ◽  
Late Triassic ◽  
Evolutionary Relationships ◽  
Early Triassic ◽  
Permian Extinction ◽  
Recovery Dynamics

AbstractThe Order Spiriferinida spanning the latest Ordovician to Early Jurassic is a small group of brachiopods overshadowed by other taxon-rich clades during the Paleozoic. It diversified significantly after the end-Permian extinction and became one of the four major clades of Triassic brachiopods. However, the phylogeny and recovery dynamics of this clade during the Triassic still remain unknown. Here, we present a higher-level parsimony-based phylogenetic analysis of Mesozoic spiriferinids to reveal their evolutionary relationships. Ecologically related characters are analyzed to indicate the variances in ecomorphospace occupation and disparity of spiriferinids through the Permian–Triassic (P-Tr) transition. For comparison with potential competitors of the spiriferinids, the pre-extinction spiriferids are also included in the analysis. Phylogenetic trees demonstrate that about half of the Mesozoic families appeared during the Anisian, indicating the greatest phylogenetic diversification at that time. Triassic spiriferinids reoccupied a large part of the ecomorphospace released by its competitor spiriferids during the end-Permian extinction; they also fully exploited the cyrtiniform region and developed novel lifestyles. Ecomorphologic disparity of the spiriferinids dropped greatly in the Early Triassic, but it rebounded rapidly and reached the level attained by the pre-extinction spiriferids in the Late Triassic. The replacement in ecomorphospace occupation between spiriferids and spiriferinids during the P-Tr transition clearly indicates that the empty ecomorphospace released by the extinction of Permian spiriferids was one of the important drivers for the diversification of the Triassic spiriferinids. The Spiriferinida took over the empty ecomorphospace and had the opportunity to flourish.

scholarly journals A new stem group echinoid from the Triassic of China leads to a revised macroevolutionary history of echinoids during the end-Permian mass extinction

2018 ◽  
Vol 5 (1) ◽  
pp. 171548 ◽  
Author(s):  
Jeffrey R. Thompson ◽  
Shi-xue Hu ◽  
Qi-Yue Zhang ◽  
Elizabeth Petsios ◽  
Laura J. Cotton ◽  
...  
Keyword(s):  
Mass Extinction ◽  
Middle Triassic ◽  
Phylogenetic Analyses ◽  
Early Triassic ◽  
Crown Group ◽  
Stem Group ◽  
History Of ◽  
Permian Mass Extinction ◽  
Lazarus Effect ◽  
A New Species

The Permian–Triassic bottleneck has long been thought to have drastically altered the course of echinoid evolution, with the extinction of the entire echinoid stem group having taken place during the end-Permian mass extinction. The Early Triassic fossil record of echinoids is, however, sparse, and new fossils are paving the way for a revised interpretation of the evolutionary history of echinoids during the Permian–Triassic crisis and Early Mesozoic. A new species of echinoid, Yunnanechinus luopingensis n. sp. recovered from the Middle Triassic (Anisian) Luoping Biota fossil Lagerstätte of South China, displays morphologies that are not characteristic of the echinoid crown group. We have used phylogenetic analyses to further demonstrate that Yunnanechinus is not a member of the echinoid crown group. Thus a clade of stem group echinoids survived into the Middle Triassic, enduring the global crisis that characterized the end-Permian and Early Triassic. Therefore, stem group echinoids did not go extinct during the Palaeozoic, as previously thought, and appear to have coexisted with the echinoid crown group for at least 23 million years. Stem group echinoids thus exhibited the Lazarus effect during the latest Permian and Early Triassic, while crown group echinoids did not.

scholarly journals The earliest equatorial record of frogs from the Late Triassic of Arizona

2019 ◽  
Vol 15 (2) ◽  
pp. 20180922 ◽  
Author(s):  
Michelle R. Stocker ◽  
Sterling J. Nesbitt ◽  
Ben T. Kligman ◽  
Daniel J. Paluh ◽  
Adam D. Marsh ◽  
...  
Keyword(s):  
Phylogenetic Analyses ◽  
Equatorial Region ◽  
Late Triassic ◽  
Early Triassic ◽  
High Latitudes ◽  
Crown Group ◽  
Stratigraphic Sequence ◽  
Terrestrial Vertebrates ◽  
Early Mesozoic ◽  
Molecular Phylogenetic

Crown-group frogs (Anura) originated over 200 Ma according to molecular phylogenetic analyses, though only a few fossils from high latitudes chronicle the first approximately 60 Myr of frog evolution and distribution. We report fossils that represent both the first Late Triassic and the earliest equatorial record of Salientia, the group that includes stem and crown-frogs. These small fossils consist of complete and partial ilia with anteriorly directed, elongate and distally hollow iliac blades. These features of these ilia, including the lack of a prominent dorsal protuberance and a shaft that is much longer than the acetabular region, suggest a closer affinity to crown-group Anura than to Early Triassic stem anurans Triadobatrachus from Madagascar and Czatkobatrachus from Poland, both high-latitude records. The new fossils demonstrate that crown anurans may have been present in the Late Triassic equatorial region of Pangea. Furthermore, the presence of Early Jurassic anurans in the same stratigraphic sequence ( Prosalirus bitis from the Kayenta Formation) suggests that anurans survived the climatic aridification of this region in the early Mesozoic. These fossils highlight the importance of the targeted collection of microfossils and provide further evidence for the presence of crown-group representatives of terrestrial vertebrates prior to the end-Triassic extinction.

Diversity and distribution of Triassic bryozoans in the aftermath of the end-Permian mass extinction

2008 ◽  
Vol 82 (2) ◽  
pp. 362-371 ◽  
Author(s):  
Catherine M. Powers ◽  
Joseph F. Pachut
Keyword(s):  
Surface Area ◽  
Mass Extinction ◽  
Carbonate Rock ◽  
Middle Triassic ◽  
Late Triassic ◽  
Early Triassic ◽  
Diversity Pattern ◽  
Extinction Rates ◽  
Permian Mass Extinction ◽  
Early Late

Seventy-three species of stenolaemate bryozoans are documented worldwide from the Triassic. Stage-level diversity and paleogeographical analyses reveal that the recovery of bryozoans following the end-Permian mass extinction was delayed until the Middle Triassic. Early Triassic bryozoans faunas, dominated by members of the Order Trepostomida, were depauperate and geographically restricted. Bryozoan diversity increased during the Middle Triassic and diversity peaked in the Carnian (early Late Triassic). High extinction rates throughout the Late Triassic led to the extinction of all stenolaemate orders except the Cyclostomida by the end of the Triassic. Comparisons between global carbonate rock volume, outcrop surface area, and bryozoan diversity indicate that the documented diversity pattern for bryozoans may have been related, in part, to the availability of carbonate environments during the Triassic.

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