scholarly journals The Early Permian fossil record of Gondwana and its relationship to deglaciation: a review

2018 ◽  
pp. 169-189 ◽  
Author(s):  
M.H. Stephenson ◽  
L. Angiolini ◽  
M.J. Leng
Keyword(s):  
Fossil Record ◽  
Early Permian

A Survey of Mammalian Origins

1984 ◽  
Vol 8 ◽  
pp. 32-47
Author(s):  
Farish A. Jenkins
Keyword(s):  
Fossil Record ◽  
Early Jurassic ◽  
The Other ◽  
Current Understanding ◽  
Late Triassic ◽  
Early Permian ◽  
Substantial Modification ◽  
Evolution Of Mammals

The origin of mammals, often treated as a discrete but obscure event that took place sometime between the Late Triassic and Early Jurassic, can also be viewed as the product of many transitions - from the early synapsid radiations during the Pennsylvanian and Early Permian through the emergence of placentals and marsupials in the Cretaceous (see Hopson, 1969). A fundamental dichotomy appeared early in the evolution of amniotes; sauropsids (represented today by living reptiles and birds) constituted one lineage, synapsids (which includes the mammal-like reptiles- pelycosaurs and therapsids- and their mammalian descendants) the other. Thus, mammalian ancestry may be traced to pelycosaurs that first appear in the fossil record as part of the earliest known reptilian fauna (Carroll, 1982). And mammalian bony and dental structures continued to undergo substantial modification throughout the Mesozoic, long after the appearance of forms technically classified as Mammalia. Given these phylogenetic changes, the suggestion that there occurred a point when mammals “originated” seems simplistic. Yet the major evolutionary stages may still be evaluated with the purpose of identifying the inception of features and functions basic to the radiation of modern mammals. Accordingly, this survey summarizes our current understanding of the evolution of mammals with full acknowledgment that an account of mammalian origins has neither a definitive beginning nor a climactic end.

Geological and palaeontological information and phylogenetic hypotheses

1988 ◽  
Vol 125 (3) ◽  
pp. 207-227 ◽  
Author(s):  
K. S. W. Campbell ◽  
R. E. Barwick
Keyword(s):  
Functional Morphology ◽  
Fossil Record ◽  
Early Permian ◽  
Phylogenetic Hypothesis ◽  
Geological Data ◽  
Early Devonian ◽  
Aerial Respiration ◽  
Phylogenetic Relations ◽  
Phylogenetic Hypotheses ◽  
Physiological Characters

AbstractA number of workers have accepted the proposition that phylogenetic relations between extant organisms can be determined only by reference to the characters of those organisms. Palaeontological data, it is said, have not been useful for developing or refuting such hypotheses. This view may be tested by reference to the respiratory mechanisms of dipnoans (lungfishes) and amphibians. The structure of the heart, lungs, and circulatory systems has been used by various authors to support the view that these are sister groups. Geological data derived from stratigraphy, palaeoecology, taphonomy, geochemistry and functional morphology of primitive dipnoans is used herein to show that these organisms did not engage in aerial respiration. The first unequivocal evidence that dipnoans had become air breathers is from aestivation burrows in Early Permian rocks of the U.S.A. The Dipnoi must have evolved this capacity at some time between the Early Devonian, when the group became well established, and the Early Permian. Similarities between the respiratory systems of extant dipnoans and amphibians must be the result of convergence, or of the derivation of the Amphibia directly from the Dipnoi. The latter view is not currently accepted by any workers in the field. Thus data from the fossil record are used to demonstrate the invalid use of some neontological data for the development of a phylogenetic hypothesis. Classifications of extant organisms depending on putative shared–derived morphological or physiological characters that cannot be adequately tested for convergence by reference to fossils, must be regarded with due caution.

scholarly journals A new Early Permian reptile and its significance in early diapsid evolution

2011 ◽  
Vol 278 (1725) ◽  
pp. 3731-3737 ◽  
Author(s):  
Robert R. Reisz ◽  
Sean P. Modesto ◽  
Diane M. Scott
Keyword(s):  
Phylogenetic Analysis ◽  
Fossil Record ◽  
Sedimentary Rocks ◽  
Sister Group ◽  
Flood Plain ◽  
Middle Permian ◽  
Lower Permian ◽  
Early Permian ◽  
Terrestrial Vertebrate

The initial stages of evolution of Diapsida (the large clade that includes not only snakes, lizards, crocodiles and birds, but also dinosaurs and numerous other extinct taxa) is clouded by an exceedingly poor Palaeozoic fossil record. Previous studies had indicated a 38 Myr gap between the first appearance of the oldest diapsid clade (Araeoscelidia), ca 304 million years ago (Ma), and that of its sister group in the Middle Permian ( ca 266 Ma). Two new reptile skulls from the Richards Spur locality, Lower Permian of Oklahoma, represent a new diapsid reptile: Orovenator mayorum n. gen. et sp. A phylogenetic analysis identifies O. mayorum as the oldest and most basal member of the araeoscelidian sister group. As Richards Spur has recently been dated to 289 Ma, the new diapsid neatly spans the above gap by appearing 15 Myr after the origin of Diapsida. The presence of O. mayorum at Richards Spur, which records a diverse upland fauna, suggests that initial stages in the evolution of non-araeoscelidian diapsids may have been tied to upland environments. This hypothesis is consonant with the overall scant record for non-araeoscelidian diapsids during the Permian Period, when the well-known terrestrial vertebrate communities are preserved almost exclusively in lowland deltaic, flood plain and lacustrine sedimentary rocks.

scholarly journals A small caseid synapsid, Arisierpeton simplex gen. et sp. nov., from the early Permian of Oklahoma, with a discussion of synapsid diversity at the classic Richards Spur locality

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e6615 ◽  
Author(s):  
Robert R. Reisz
Keyword(s):  
North America ◽  
Fossil Record ◽  
Middle Permian ◽  
Lower Permian ◽  
Early Permian ◽  
Faunal Assemblage ◽  
Lower Jaw ◽  
Continental Deposits ◽  
Faunal List ◽  
Taxic Diversity

The fossil record of caseids, a clade of faunivorous to large herbivorous Permian synapsids, is unusual in having a poorly documented history. Although Kungurian caseids are common in the well-known continental deposits of North America, and the fossil record of the group extends into the middle Permian (Guadalupian), with the presence of the large caseid Ennatosaurus in the Mezen Basin faunal assemblage, only two other occurrences are known in older Permian age sediments. One is an undescribed caseid from the Bromacker Quarry in Germany, and the second is Oromycter from the lower Permian of Richards Spur, Oklahoma. The former is known from several articulated skeletons, but the latter is known only from a handful of skeletal elements, including elements of the snout and lower jaw, some phalanges, and a few vertebrae. Here the fragmentary tooth bearing elements and dorsal vertebrae of another small caseid from Richards Spur are described, with a discussion of its significance in the context of caseid evolution, and the continuously expanding faunal list and taxic diversity at this locality.

scholarly journals The youngest trigonotarbid Permotarbus schuberti n. gen., n. sp. from the Permian Petrified Forest of Chemnitz in Germany

Fossil Record ◽  
2013 ◽  
Vol 16 (2) ◽  
pp. 229-243 ◽  
Author(s):  
J. A. Dunlop ◽  
R. Rößler
Keyword(s):  
North America ◽  
Coal Mining ◽  
Fossil Record ◽  
Late Carboniferous ◽  
Early Permian ◽  
Mining Districts ◽  
Coal Measures ◽  
Moscovian Stage ◽  
Broad Overview ◽  
Petrified Forest

A new trigonotarbid (Arachnida: Trigonotarbida) is described as <i>Permotarbus schuberti</i> n. gen., n. sp. from the Early Permian Petrified Forest (Rotliegend) of Chemnitz in Saxony (Germany). At ca. 290 Ma it represents the youngest record of this extinct arachnid order discovered to date. Its familial affinities are uncertain, but may lie close to the Aphantomartidae. The distribution of the trigonotarbid genera through time is summarised, together with a list of their seventy-seven fossil-yielding localities. Together they offer a broad overview of the group's fossil record, which is heavily biased towards the Moscovian Stage (ca. 307–312 Ma) of the Late Carboniferous in Europe and North America. This is due in no small part to numerous localities associated with coal mining districts, and trigonotarbids are found less frequently after this stage. While it is tempting to associate this with biological events – such as a putative "Carboniferous Rainforest Collapse" dating to ca. 305 Ma – it is difficult to differentiate the effects of genuine extinction patterns from artefacts caused by fewer appropriate localities in the economically less relevant latest Carboniferous and Early Permian strata. Nevertheless, trigonotarbids became extinct at some point after the Early Permian and loss of the Coal Measures forests remains one of the most likely possible causes. <br><br> doi:<a href="http://dx.doi.org/10.1002/mmng.201300012" target="_blank">10.1002/mmng.201300012</a>

Re-evaluation of an early sphenacodontian synapsid from the Lower Permian of England

2019 ◽  
Vol 111 (1) ◽  
pp. 27-37 ◽  
Author(s):  
Frederik SPINDLER
Keyword(s):  
Fossil Record ◽  
Ecological Model ◽  
Lower Permian ◽  
New Taxon ◽  
Early Permian ◽  
Tolerance Range ◽  
Environmental Tolerance ◽  
Unique Character ◽  
Mosaic Distribution

ABSTRACTThe holotypic isolated maxilla of the early sphenacodontian Haptodus grandis from the Cisuralian of England is revisited. A unique character combination includes haptodontine-grade traits like less specialised teeth and a high number of precanines, but at the same time a shortened lacrimal that is separated from the naris, which is strongly diagnostic of Sphenacodontoidea. As the specimen cannot be assigned to any known taxon, the new taxon Hypselohaptodus grandis gen. nov. is proposed. Comparison with other sphenacodontians reveals a mosaic distribution of maxillary features, most significantly regarding the precanine region. Preliminary character histories preclude Hypselohaptodus from Sphenacodontidae, but suggest a haptodontine-grade or basal therapsid position. The latter hypothesis is substantiated by an ecological model of episodic wet phases in an overall trend of aridification throughout the Permian, to explain the rareness of non-sphenacodontid sphenacodontians in the fossil record. Also from the early Permian of England, an isolated dentary has previously been assigned to Ophiacodon, but can be shown to be either a sphenacodontian, possibly affiliated with Hypselohaptodus, or a robust, Stereorhachis-like ophiacodontid. The absence of Ophiacodon in the intramontaneous Permian basis of Europe is explained by a narrow environmental tolerance range requiring limnic connection with lowland basins.

Darwin's two competing phylogenetic trees: marsupials as ancestors or sister taxa?

2012 ◽  
Vol 39 (2) ◽  
pp. 217-233 ◽  
Author(s):  
J. David Archibald
Keyword(s):  
Fossil Record ◽  
Evolutionary Biology ◽  
Phylogenetic Trees ◽  
Charles Darwin ◽  
The Other ◽  
Charles Lyell ◽  
Single Origin ◽  
Molecular Studies ◽  
Richard Owen ◽  
First Time

Studies of the origin and diversification of major groups of plants and animals are contentious topics in current evolutionary biology. This includes the study of the timing and relationships of the two major clades of extant mammals – marsupials and placentals. Molecular studies concerned with marsupial and placental origin and diversification can be at odds with the fossil record. Such studies are, however, not a recent phenomenon. Over 150 years ago Charles Darwin weighed two alternative views on the origin of marsupials and placentals. Less than a year after the publication of On the origin of species, Darwin outlined these in a letter to Charles Lyell dated 23 September 1860. The letter concluded with two competing phylogenetic diagrams. One showed marsupials as ancestral to both living marsupials and placentals, whereas the other showed a non-marsupial, non-placental as being ancestral to both living marsupials and placentals. These two diagrams are published here for the first time. These are the only such competing phylogenetic diagrams that Darwin is known to have produced. In addition to examining the question of mammalian origins in this letter and in other manuscript notes discussed here, Darwin confronted the broader issue as to whether major groups of animals had a single origin (monophyly) or were the result of “continuous creation” as advocated for some groups by Richard Owen. Charles Lyell had held similar views to those of Owen, but it is clear from correspondence with Darwin that he was beginning to accept the idea of monophyly of major groups.

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