morotodon is the ONLY member of the family herpetotheriidae to have EVER made it to africa and one of three of the family to make it to the miocene along with herpetotherium in the united states and amphiperatherium in western europe. how did a line of metatherians survive for millions of years in africa completely undetected? what adaptations did morotodon have that allowed it to compete with eutherians for so long? will we ever find more fossils of morotodon? are there paleontologists actively looking for morotodon? is this all a scam? should i go to sleep because it's 3 am? we might never know

Eutherian mammals and saurischian dinosaurs both evolved lineages of huge terrestrial herbivores. Although significantly more saurischian dinosaurs were giants than eutherians, the long bones of both taxa scale similarly and suggest that locomotion was dynamically similar. However, articular cartilage is thin in eutherian mammals but thick in saurischian dinosaurs, differences that could have contributed to, or limited, how frequently gigantism evolved. Therefore, we tested the hypothesis that sub-articular bone, which supports the articular cartilage, changes shape in different ways between terrestrial mammals and dinosaurs with increasing size. Our sample consisted of giant mammal and reptile taxa (i.e., elephants, rhinos, sauropods) plus erect and non-erect outgroups with thin and thick articular cartilage. Our results show that eutherian mammal sub-articular shape becomes narrow with well-defined surface features as size increases. In contrast, this region in saurischian dinosaurs expands and remains gently convex with increasing size. Similar trends were observed in non-erect outgroup taxa (monotremes, alligators), showing that the trends we report are posture-independent. These differences support our hypothesis that sub-articular shape scales differently between eutherian mammals and saurischian dinosaurs. Our results show that articular cartilage thickness and sub-articular shape are correlated. In mammals, joints become ever more congruent and thinner with increasing size, whereas archosaur joints remained both congruent and thick, especially in sauropods. We suggest that gigantism occurs less frequently in mammals, in part, because joints composed of thin articular cartilage can only become so congruent before stress cannot be effectively alleviated. In contrast, frequent gigantism in saurischian dinosaurs may be explained, in part, by joints with thick articular cartilage that can deform across large areas with increasing load.

Leptictida is the larger clade that includes Leptictidium and its kin. The first members of this group appear in the latest Cretaceous of western North America and the order quickly spreads throughout the northern continents, lasting until the early Oligocene about 30 million years ago, when the forests worldwide started to give way to grasslands. Previously leptictids were thought to be related to either the living lipotyphla (hedgehogs, shrews, and moles) or elephant shrews, but recent studies of the relationships of mammals have placed them outside of placental mammals entirely, making them stem eutherians and not members of Placentalia. 

Basilosaurus is not closely related to any modern whales, diverging from the cetacean lineage prior to the odontocete (toothed whale) mysticete (baleen whales) spilt. Though it is not the longest whale ever known, at 'only' 72 feet (22 meters) long , it reached this length in a manner unlike modern cetaceans. All of this elongation comes from duplications of vertebra past the ribs whereas modern whales of this length are just overall bigger in all aspects - Basilosaurus was extremely narrow for its body length. Basilosaurus did not swim like modern whales, which move the whole tail as one unit, instead it is thought it swam much more like an eel, with the movement undulating though the long body - though in a vertical fashion rather than horizontal. Another interesting aspect of Basilosaurus is it retained extremely small hind limbs, which were useless in locomotion. These tiny appendages were most likely used as copulatory guides, such as seen in some snakes, to make sure that the proper bits of a mating pair lined up.