A review of the fossil record of turtles of the clade Pan-Carettochelys

Turtles of the total clade Pan-Carettochelys have a relatively poor fossil record that extends from the Early Cretaceous. The clade is only found in Asia during the Cretaceous, but spreads to Europe and North America during the Eocene. Neogene finds are restricted to Europe, Africa and Australia, whereas the only surviving species, Carettochelys insculpta, lives in New Guinea and the Northern Territories of Australia. The ecology of fossil pan-carettochelyids appears similar to that of the extant C. insculpta, although more primitive representatives were likely less adapted to brackish water. Current phylogenies only recognize three internested clades: Pan- Carettochelys, Carettochelyidae and Carettochelyinae. A taxonomic review of the group concludes that of 25 named taxa, 13 are nomina valida, 7 are nomina invalida, 3 are nomina dubia, and 2 are nomina nuda

Caught in the act: the first record of copulating fossil vertebrates

The behaviour of fossil organisms can typically be inferred only indirectly, but rare fossil finds can provide surprising insights. Here, we report from the Eocene Messel Pit Fossil Site between Darmstadt and Frankfurt, Germany numerous pairs of the fossil carettochelyid turtle Allaeochelys crassesculpta that represent for the first time among fossil vertebrates couples that perished during copulation. Females of this taxon can be distinguished from males by their relatively shorter tails and development of plastral kinesis. The preservation of mating pairs has important taphonomic implications for the Messel Pit Fossil Site, as it is unlikely that the turtles would mate in poisonous surface waters. Instead, the turtles initiated copulation in habitable surface waters, but perished when their skin absorbed poisons while sinking during into toxic layers. The mating pairs from Messel are therefore more consistent with a stratified, volcanic maar lake with inhabitable surface waters and a deadly abyss

Mammary odor cues and pheromones: mammalian infant-directed communication about maternal state, mammae, and milk.

International audienceNeonatal mammals are exposed to an outstandingly powerful selective pressure at birth, and any mean to alleviate their localization effort and accelerate acceptance to orally grasp a nipple and ingest milk should have had advantageous consequences over evolutionary time. Thus, it is essential for females to display a biological interface structure that is sensorily conspicuous and executively easy for their newborns. Females' strategy to increase the conspicuousness of nipples could only exploit the newborns' most advanced and conserved sensory systems, touch and olfaction, and selection has accordingly shaped tactilely and olfactorily conspicuous mammary structures. This evolutionary modification has worked either by affecting structural features of mammaries or indirectly by affecting maternal behavioral propensities to create olfactory traces on them. These predictions are considered here in mammalian cases that have received empirical attention among marsupials, rodents, lagomorphs, ungulates, carnivores, and primates. It appears that broadcasting chemical cues and/or signals from the mammae is a pan-mammalian reproductive strategy to pilot neonatal arousal, motivation and attraction to the mother, provide assistance in localizing and orally grasping the mammae, and boost up learning. But the ways by which these chemical cues are produced and assembled on the mammae are both diverse between species and complex within species, offering an outstanding opportunity for comparative analyses in chemical communication