Tritheledontids are advanced cynodonts that are considered the sister group of Mammalia. To date the postcranial skeleton has remained largely unknown, so that cladistic analyses are based on cranial characters only. This paper describes a specimen of the tritheledontid Pachygenelus which has most of the skull and vertebral column, a complete shoulder girdle, and most of the forelimb. The girdl...

has celebrated. This poetical and transcendental idea has so dominated the lay and scientific mind that even now the question of hermaphroditism in the mammalia is discussed and supported by the description of specimens with alleged ova and spermatozoa in a common sex gland, or of those where the opposite sex-duct element is unduly represented at the expense, we shall see, of the potent normal ...

About the extent of moral agency in the animal kingdom, one view is that only humans are moral agents. Holding a different view, I argue that moral agency depends on the capacity for other-regard and the capacity to be attuned to significance—such that things matter to one. I derive a criterion where a creature is a moral agent if she performs an action that promotes others’ significant interes...

A phylogeny of tetrapods is inferred from nearly complete sequences of the nuclear RAG-1 gene sampled across 88 taxa encompassing all major clades, analyzed via parsimony and Bayesian methods. The phylogeny provides support for Lissamphibia, Theria, Lepidosauria, a turtle-archosaur clade, as well as most traditionally accepted groupings. This tree allows simultaneous molecular clock dating for ...

In the effort to understand the evolution of mammalian brains, we have found that common relationships between brain structure mass and numbers of nonneuronal (glial and vascular) cells apply across eutherian mammals, but brain structure mass scales differently with numbers of neurons across structures and across primate and nonprimate clades. This suggests that the ancestral scaling rules for ...

The presence of Chionomys nivalis (Martins, 1842) (Mammalia Rodentia Cricetidae) in Calabria, the southern tip of the Italian peninsula, is reported in different literature sources, but the only Calabrian specimen, from Lago Cecita, Cosenza district, is preserved into Museo Zoologico “La Specola”, Firenze. A recent examination of this specimen, moreover, has shown that it is an Arvicola amphibi...

Reproductive proteins are among the most rapidly evolving classes of proteins. For a subset of these, rapid evolution is driven by positive Darwinian selection despite vital, well-conserved, reproductive functions. Izumo1 is the only essential sperm-egg fusion protein currently known on mammalian sperm, and its egg receptor (Juno; formerly Folr4) was recently discovered. Male knockout mice for ...

Explaining variability in offspring vs. adult size among groups is a necessary step to determine the evolutionary and environmental constraints shaping variability in life history strategies. This is of particular interest for life in the ocean where a diversity of offspring development strategies is observed along with variability in physical and biological forcing factors in space and time. W...