scholarly journals Cortical interlaminar astrocytes across the therian mammal radiation

2019 ◽  
Vol 527 (10) ◽  
pp. 1654-1674 ◽  
Author(s):  
Carmen Falcone ◽  
Marisol Wolf‐Ochoa ◽  
Sarwat Amina ◽  
Tiffany Hong ◽  
Gelareh Vakilzadeh ◽  
...  
Keyword(s):  
Therian Mammal

A new, unusual therian mammal from the Upper Cretaceous of Saskatchewan, Canada

2007 ◽  
Vol 28 (5) ◽  
pp. 821-829 ◽  
Author(s):  
Richard C. Fox ◽  
Craig S. Scott ◽  
Harold N. Bryant
Keyword(s):  
Upper Cretaceous ◽  
Therian Mammal

Integrated hearing and chewing modules decoupled in a Cretaceous stem therian mammal

Science ◽  
2019 ◽  
Vol 367 (6475) ◽  
pp. 305-308 ◽  
Author(s):  
Fangyuan Mao ◽  
Yaoming Hu ◽  
Chuankui Li ◽  
Yuanqing Wang ◽  
Morgan Hill Chase ◽  
...  
Keyword(s):  
Middle Ear ◽  
New Genus ◽  
New Genus And Species ◽  
Bone Contact ◽  
Meckel's Cartilage ◽  
Therian Mammal ◽  
Meckel’S Cartilage ◽  
Genetic Mechanisms ◽  
Evolution Of Mammals

On the basis of multiple skeletal specimens from Liaoning, China, we report a new genus and species of Cretaceous stem therian mammal that displays decoupling of hearing and chewing apparatuses and functions. The auditory bones, including the surangular, have no bone contact with the ossified Meckel’s cartilage; the latter is loosely lodged on the medial rear of the dentary. This configuration probably represents the initial morphological stage of the definitive mammalian middle ear. Evidence shows that hearing and chewing apparatuses have evolved in a modular fashion. Starting as an integrated complex in non-mammaliaform cynodonts, the two modules, regulated by similar developmental and genetic mechanisms, eventually decoupled during the evolution of mammals, allowing further improvement for more efficient hearing and mastication.

scholarly journals The oldest modern therian mammal from Europe and its bearing on stem marsupial paleobiogeography

2009 ◽  
Vol 106 (47) ◽  
pp. 19910-19915 ◽  
Author(s):  
R. Vullo ◽  
E. Gheerbrant ◽  
C. de Muizon ◽  
D. Neraudeau
Keyword(s):  
Therian Mammal

Mammals from the Upper Cretaceous Oldman Formation, Alberta. II. Pediomys Marsh (Marsupialia)

1979 ◽  
Vol 16 (1) ◽  
pp. 103-113 ◽  
Author(s):  
Richard C. Fox
Keyword(s):  
South America ◽  
Upper Cretaceous ◽  
Therian Mammal ◽  
Direct Ancestor

Pediomys Marsh, a primitive marsupicarnivore, is the most common therian mammal known from the Upper Cretaceous Oldman Formation, Alberta, where it is represented by at least four species. The first, P. clemensi Sahni, appears closely related to the Lancian P. cooki Clemens; other species, poorly represented by fossils, resemble the Lancian P. elegans Marsh and P. hatcheri respectively; a final species, which is new, is interpreted as the direct ancestor of the Lancian P. krejcii Clemens. Pediomys shows trends toward enhancement of a crushing rather than a shearing function of the postcanine dentition and, consequently, seems not ancestral to the Cenozoic 'dog-like' marsupials of Australia and South America, contrary to recent suggestions elsewhere.

Injection of a boar sperm factor causes calcium oscillations in oocytes of the marsupial opossum, Monodelphis domestica

Zygote ◽  
1999 ◽  
Vol 7 (4) ◽  
pp. 271-277 ◽  
Author(s):  
C. J. Witton ◽  
K. Swann ◽  
J. Carroll ◽  
H. D. M. Moore
Keyword(s):  
Calcium Oscillations ◽  
Monodelphis Domestica ◽  
Egg Activation ◽  
Therian Mammal ◽  
Repetitive Nature ◽  
Boar Sperm ◽  
Sperm Extract ◽  
Sperm Factor ◽  
Oocyte Cytoplasm ◽  
Control Injection

At fertilisation, the sperm triggers an abrupt and transient increase in intracellular calcium ([Ca2+]i) in the oocyte cytoplasm. In eutherian mammals, oocytes exhibit multiple [Ca2+]i transients which are necessary for egg activation. We investigated [Ca2+]i in the marsupial opossum, Monodelphis domestica. Embryo development in this therian mammal is quite distinct from that in most Eutheria. Oestrus was induced in an adult female opossum by introduction of a male into her cage. Injection of a boar sperm extract induced repetitive increases in [Ca2+]i. Each oscillation travelled across and around the periphery of the egg in a wave-like manner. A control injection of KCl elicited no change in [Ca2+]i. This is the first observation of [Ca2+]i oscillations in the oocyte of a marsupial. The repetitive nature of the [Ca2+]i changes were more similar to those in oocytes of Eutheria than those in oocytes of non-mammalian vertebrates.

Picopsis pattersoni, n.gen. and sp., an unusual therian from the Upper Cretaceous of Alberta, and the classification of primitive tribosphenic mammals

1980 ◽  
Vol 17 (11) ◽  
pp. 1489-1498 ◽  
Author(s):  
Richard C. Fox
Keyword(s):  
Upper Cretaceous ◽  
Therian Mammal ◽  
New Family ◽  
Milk River Formation

A new therian mammal of primitive tribosphenic grade is described from the Upper Milk River Formation (Upper Cretaceous) of Alberta, Canada, and its relationships to other primitive tribosphenic therians are discussed. The new therian and its presumed nearest relatives form the basis of a new family within the Order Aegialodontia. A revised classification of the Infraclass Tribotheria is presented.

scholarly journals A derived dryolestid mammal indicates possible insular endemism in the Late Jurassic of Germany

2021 ◽  
Vol 108 (3) ◽  
Author(s):  
Thomas Martin ◽  
Alexander O. Averianov ◽  
Julia A. Schultz ◽  
Achim H. Schwermann ◽  
Oliver Wings
Keyword(s):  
Phylogenetic Analysis ◽  
Early Cretaceous ◽  
Lower Cretaceous ◽  
Middle Jurassic ◽  
Late Jurassic ◽  
New Taxon ◽  
Lower Saxony ◽  
Therian Mammal ◽  
Geological Age ◽  
Near Shore

AbstractThe Langenberg Quarry near Bad Harzburg has yielded the first Jurassic stem therian mammal of Germany, recovered from Kimmeridgian (Late Jurassic) near shore deposits of a palaeo-island within the Lower Saxony Basin of the European archipelago. The new stem therian is represented by one lower and three upper molars. Hercynodon germanicus gen. et sp. nov. is attributed to the Dryolestidae, a group of pretribosphenic crown mammals that was common in western Laurasia from the Middle Jurassic to the Early Cretaceous. The new taxon is characterised by small size, a reduced cusp pattern in the upper molars lacking a metacone, and enhancement of the shearing crests paracrista and metacrista. Phylogenetic analysis identified Hercynodon gen. nov. as sister taxon of Crusafontia from the Lower Cretaceous (Barremian) of Spain. Both taxa belong to an endemic European clade of dryolestids, including also Achyrodon and Phascolestes from the earliest Cretaceous (Berriasian) of England. Despite its greater geological age, Hercynodon gen. nov. is the most derived representative of that clade, indicated by the complete reduction of the metacone. The discrepancy between derived morphology and geological age may be explained by an increased rate of character evolution in insular isolation. Other insular phenomena have earlier been observed in vertebrates from the Langenberg Quarry, such as dwarfism in the small sauropod Europasaurus, and possible gigantism in the morganucodontan mammaliaform Storchodon and the pinheirodontid multituberculate mammal Teutonodon which grew unusually large.

The earliest Tertiary therian mammal from South America

2006 ◽  
Vol 26 (2) ◽  
pp. 505-510 ◽  
Author(s):  
Francisco J. Goin ◽  
Rosendo Pascual ◽  
Marcelo F. Tejedor ◽  
Javier N. Gelfo ◽  
Michael O. Woodburne ◽  
...  
Keyword(s):  
South America ◽  
Therian Mammal
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