scholarly journals Permian–Triassic phylogenetic and morphologic evolution of rhynchonellide brachiopods

Paleobiology ◽  
2021 ◽  
pp. 1-21
Author(s):  
Zhen Guo ◽  
Zhong-Qiang Chen ◽  
David A. T. Harper ◽  
Yuangeng Huang
Keyword(s):  
Middle Triassic ◽  
Ancestral State ◽  
Mass Extinctions ◽  
Shell Size ◽  
Morphologic Evolution ◽  
Major Increase ◽  
Fossil Records ◽  
Multiple Trees ◽  
Early Middle Triassic ◽  
Pronounced Reduction

Abstract The Rhynchonellida is a major group of brachiopods that survived the “big five” mass extinctions and flourished after the Permian/Triassic (P/Tr) crisis. However, phylogenetic and character evolution in the Rhynchonellida across the P/Tr transition is poorly understood. In view of the widespread homoplasy across this order, we employ a tip-dated Bayesian analysis to reconstruct phylogenetic relationships for late Permian–Triassic rhynchonellides. The same data were also analyzed using three other methods: undated Bayesian, equal-weighting, and implied-weighting parsimony. Compared with trees generated by other methods, those constructed by tip-dating best account for the homoplasy in this group and are closer to previous assumptions on the evolution of this order. Based on the analyses of multiple trees, the major increase in lineage richness occurred in the Early and early Middle Triassic. Also, richness in the Anisian almost reached the highest level seen in the Triassic. According to fossil records, a pronounced reduction in shell size and in the development of ornamentation occurred after the P/Tr extinction, which is largely due to the loss of large and highly sculptured genera and the diversification of small-sized and weakly ornamented genera. Ancestral-state estimation of shell size and development of ornamentation, coupled with comparisons of other characters, indicate that the Early–Middle Triassic mature “small-sized taxa” may have characters displayed by juveniles of their ancestors. This suggests that for these genera, paedomorphosis was possibly a strategy to survive and diversify in the harsh environment after the P/Tr extinction.

scholarly journals The early Triassic rhynchosaur Mesosuchus browni and the interrelationships of basal archosauromorph reptiles

1998 ◽  
Vol 353 (1368) ◽  
pp. 501-541 ◽  
Author(s):  
David W. Dilkes
Keyword(s):  
Middle Triassic ◽  
Sister Group ◽  
Recent Common Ancestor ◽  
Early Triassic ◽  
Late Permian ◽  
Assemblage Zone ◽  
Stratigraphic Ranges ◽  
Permian Mass Extinction ◽  
Fossil Records ◽  
Early Middle Triassic

Restudy of the unique diapsid reptile Mesosuchus browni Watson, from the Cynognathus Assemblage Zone (late Early Triassic to early Middle Triassic) of the Burgersdorp Formation (Tarkastad Subgroup; Beaufort Group) of South Africa, confirms that it is the most plesiomorphic known member of the Rhynchosauria. A new phylogenetic analysis of basal taxa of Archosauromorpha indicates that Choristodera falls outside of the Sauria, Prolacertiformes is a paraphyletic taxon with Prolacerta sharing a more recent common ancestor with Archosauriformes than with any other clade, Megalancosaurus and Drepanosaurus are sister taxa in the clade Drepanosauridae within Archosauromorpha, and are the sister group to the clade Tanystropheidae composed of Tanystropheus , Macrocnemus , and Langobardisaurus . Combination of the phylogenetic relationships of basal archosauromorphs and their known stratigraphic ranges reveals significant gaps in the fossil records of Late Permian and Triassic diapsids. Extensions of the temporal ranges of several lineages of diapsids into the Late Permian suggests that more groups of terrestrial reptiles survived the end-Permian mass extinction than thought previously.

Post-Paleozoic Patterns in Marine Predation: Was there a Mesozoic and Cenozoic Marine Predatory Revolution?

2002 ◽  
Vol 8 ◽  
pp. 119-194 ◽  
Author(s):  
Sally E. Walker ◽  
Carlton E. Brett
Keyword(s):  
Marine Mammals ◽  
Middle Triassic ◽  
Late Triassic ◽  
Mass Extinctions ◽  
Decapod Crustaceans ◽  
Late Mesozoic ◽  
Marine Reptiles ◽  
Sea Birds ◽  
Major Increase ◽  
Evolutionary Radiations

Mesozoic and Cenozoic evolution of predators involved a series of episodes. Predators rebounded rather rapidly after the Permo-Triassic extinction and by the Middle Triassic a variety of new predator guilds had appeared, including decapod crustaceans with crushing claws, shell-crushing sharks and bony fish, as well as marine reptiles adapted for crushing, smashing, and piercing shells. While several groups (e.g., placodonts, nothosaurs) became extinct in the Late Triassic crises, others (e.g., ichthyosaurs) survived; and the Jurassic to Early Cretaceous saw the rise of malacostracan crustaceans with crushing chelae and predatory vertebrates—in particular, the marine crocodilians, ichthyosaurs, and plesiosaurs. The late Cretaceous saw unprecedented levels of diversity of marine predaceous vertebrates including pliosaurids, plesiosaurs, and mosasaurs. The great Cretaceous-Tertiary extinction decimated marine reptiles. However, most invertebrate and fish predatory groups survived; and during the Paleogene, predatory benthic invertebrates showed a spurt of evolution with neogastropods and new groups of decapods, while the teleosts and neoselachian sharks both underwent parallel rapid evolutionary radiations; these were joined by new predatory guilds of sea birds and marine mammals. Thus, although escalation is sometimes cast as an ongoing “arms race,” in actuality the predatory record shows long interludes of relative stability puncturated by episodes of abrupt biotic reorganization during and after mass extinctions. This pattern suggests episodic, but generally increasing, predation pressure on marine organisms through the Mesozoic-Cenozoic interval. However, review of the Cenozoic record of predation suggests that there are not unambiguous escalatory trends in regard to antipredatory shell architecture, such as conchiolin and spines; nor do shell drilling and shell repair data show a major increase from the Late Mesozoic through the Cenozoic. Most durophagous groups are generalists, and thus it may be that they had a diffuse effect on their invertebrate prey.

scholarly journals Integrated bio- and cyclostratigraphy of Middle Triassic (Anisian) ramp deposits, NW Bulgaria

2019 ◽  
Vol 70 (4) ◽  
pp. 325-354 ◽  
Author(s):  
George Ajdanlijsky ◽  
André Strasser ◽  
Annette E. Götz
Keyword(s):  
Middle Triassic ◽  
Time Frame ◽  
Small Scale ◽  
Lateral Migration ◽  
Sea Level Changes ◽  
Orbital Cycles ◽  
Sequence Boundaries ◽  
Bounding Surfaces ◽  
Early Middle Triassic ◽  
Major Sequence

Abstract A cyclostratigraphic interpretation of peritidal to shallow-marine ramp deposits of the early Middle Triassic (Anisian) Opletnya Member exposed in outcrops along the Iskar River gorge, NW Bulgaria, is presented. Based on facies trends and bounding surfaces, depositional sequences of several orders can be identified. New biostratigraphic data provide a time frame of the studied succession with placement of the boundaries of the Anisian substages and show that the Aegean (early Anisian) substage lasted about 1.6 Myr. In the corresponding interval in the two studied sections, 80 elementary sequences are counted. Five elementary sequences compose a small-scale sequence. The prominent cyclic pattern of the Opletnya Member can thus be interpreted in terms of Milankovitch cyclicity: elementary sequences represent the precession (20-kyr) cycle and small-scale sequences the short eccentricity (100-kyr) cycle in the Milankovitch frequency band. Medium-scale sequences are defined based on lithology but only in two cases can be attributed to the long eccentricity cycle of 405 kyr. The transgressive-regressive facies trends within the sequences of all scales imply that they were controlled by sea-level changes, and that these were in tune with the climate changes induced by the orbital cycles. However, the complexity of facies and sedimentary structures seen in the Opletnya Member also implies that additional factors such as lateral migration of sediment bodies across the ramp were active. In addition, three major sequence boundaries have been identified in the studied sections, which can be correlated with the boundaries Ol4, An1, and An2 of the Tethyan realm.

The oldest Diptera (Insecta) from the Upper Buntsandstein (early Middle Triassic) of Europe

Zootaxa ◽  
2021 ◽  
Vol 5067 (1) ◽  
pp. 135-143
Author(s):  
ELENA D. LUKASHEVICH
Keyword(s):  
Fossil Record ◽  
New Genus ◽  
Middle Triassic ◽  
Insect Fauna ◽  
The Family ◽  
Lower Franconia ◽  
Grès À Voltzia ◽  
Early Middle Triassic

The fossil record of Triassic Diptera is still poor, with the oldest dipteran assemblage described from the Upper Buntsandstein of the ‘Grès à Voltzia’ Formation (early Anisian, France). From the stratigraphically closest insect fauna of the Röt Formation of Lower Franconia, Germany, the first Diptera, Bashkonia franconica gen. et sp. nov. is described based on an isolated wing. The new genus is assigned to the family Nadipteridae, bridging the gap between two other genera included.  

Early-Middle Triassic Intrusions in Western Inner Mongolia, China: Implications for the Final Orogenic Evolution in Southwestern Xing-Meng Orogenic Belt

2019 ◽  
Vol 30 (5) ◽  
pp. 977-995 ◽  
Author(s):  
Min Liu ◽  
Shaocong Lai ◽  
Da Zhang ◽  
Renzhi Zhu ◽  
Jiangfeng Qin ◽  
...  
Keyword(s):  
Inner Mongolia ◽  
Middle Triassic ◽  
Orogenic Belt ◽  
Early Middle Triassic

scholarly journals Ancestral morphology of Ecdysozoa constrained by an early Cambrian stem group ecdysozoan

2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Richard J. Howard ◽  
Gregory D. Edgecombe ◽  
Xiaomei Shi ◽  
Xianguang Hou ◽  
Xiaoya Ma
Keyword(s):  
Feeding Strategy ◽  
Phylogenetic Analyses ◽  
Morphological Diversity ◽  
Early Cambrian ◽  
Ancestral State ◽  
Crown Group ◽  
Stem Group ◽  
Chengjiang Biota ◽  
Fossil Records ◽  
Experimental Decay

Abstract Background Ecdysozoa are the moulting protostomes, including arthropods, tardigrades, and nematodes. Both the molecular and fossil records indicate that Ecdysozoa is an ancient group originating in the terminal Proterozoic, and exceptional fossil biotas show their dominance and diversity at the beginning of the Phanerozoic. However, the nature of the ecdysozoan common ancestor has been difficult to ascertain due to the extreme morphological diversity of extant Ecdysozoa, and the lack of early diverging taxa in ancient fossil biotas. Results Here we re-describe Acosmia maotiania from the early Cambrian Chengjiang Biota of Yunnan Province, China and assign it to stem group Ecdysozoa. Acosmia features a two-part body, with an anterior proboscis bearing a terminal mouth and muscular pharynx, and a posterior annulated trunk with a through gut. Morphological phylogenetic analyses of the protostomes using parsimony, maximum likelihood and Bayesian inference, with coding informed by published experimental decay studies, each placed Acosmia as sister taxon to Cycloneuralia + Panarthropoda—i.e. stem group Ecdysozoa. Ancestral state probabilities were calculated for key ecdysozoan nodes, in order to test characters inferred from fossils to be ancestral for Ecdysozoa. Results support an ancestor of crown group ecdysozoans sharing an annulated vermiform body with a terminal mouth like Acosmia, but also possessing the pharyngeal armature and circumoral structures characteristic of Cambrian cycloneuralians and lobopodians. Conclusions Acosmia is the first taxon placed in the ecdysozoan stem group and provides a constraint to test hypotheses on the early evolution of Ecdysozoa. Our study suggests acquisition of pharyngeal armature, and therefore a change in feeding strategy (e.g. predation), may have characterised the origin and radiation of crown group ecdysozoans from Acosmia-like ancestors.

Sign in / Sign up

Export Citation Format

Share Document