Once my eldest son (at the time of the dinosaur hobby) asked me a question: were there mole dinosaurs? He meant that in the Mesozoic there were lizards-herbivores and lizards-predators, lizards-“birds” and lizards-“fish”, even lizards-“sloths”. But he did not find "moles" in his children's encyclopedia. I answered him in such a way that at that time the ancestors of mammals and mammals themselves were "moles". But in reality - were there "moles" lizards or not?
There were no dinosaur moles. In general, the geological record of our planet is very incomplete and constantly surprises. Every year they find and describe the remains of new species of fossil animals, sometimes very exotic. But dinosaurs-moles are not among them and probably will not be. This follows from the general development trends of the group.
Not too many vertebrates live in the soil: some species of frogs (for example, Nasikabatrachus sahyadrensis), worms (legless amphibians), moles, shrews, mole rats, and mole rats. All of them are small in size. Large animals do not crawl in the soil - they have no need to hide under the ground.
Initially, even during their formation in the Triassic period, dinosaurs relied on large sizes and became the largest land animals of the Mesozoic. This allowed dinosaurs to dominate terrestrial ecosystems. In the Jurassic period, some dinosaurs nevertheless tried to enter the small size class, but they could not compete with small reptiles (mainly highly specialized lizards) and ancient mammals, which at that time occupied the ecological niche of small animals. Therefore, dinosaurs of small size, even from a turkey, are rare (see Dinosaur Sizes). Dinosaurs the size of a mole or frog are unknown.
Only mammals have managed to become real moles. This was probably the case. Many Mesozoic mammals most likely lived in burrows. This is indicated by a number of their features, for example, a well-developed sense of smell and a lesser role of vision - this scientists found out by studying the casts of the brain. Most likely, the owners of such features were crepuscular animals, hunted in the evening and at night, and during the day they hid in hollows and holes. Probably, the forests during the time of the dinosaurs abounded with burrows of mammals. This is indirectly indicated by the emergence of snakes, which appeared at this time as hunters for burrowing animals. Overpopulated ecological niches of crepuscular small predators should have led to the fact that some mammals left to develop the unoccupied space of the upper soil layers, where it was possible to hunt worms and insect larvae. For some, it seems to behappened. In 2015, paleontologists found in China the bones of an animal that lived in the late Jurassic period. The animal received the name Docofossor brachydactylus, which means “dokodont burrowing broad-fingered” (docodonts are an extinct group of primitive mammals). Dokofossor has specific traits that are characteristic of modern burrowing animals such as marsupial moles and golden moles. Dokofossor's paws are the paws of a specialized underground inhabitant. So now we know for sure that mole-like burrowing mammals existed already in the days of dinosaurs (for more details see the news. Analogs of modern moles, otters and primates existed already in the Jurassic period, "Elements", 02.16.2015).which means "precodont burrowing broad-fingered" (precodonts are an extinct group of primitive mammals). Dokofossor has specific traits that are characteristic of modern burrowing animals such as marsupial moles and golden moles. Dokofossor's paws are the paws of a specialized underground inhabitant. So now we know for sure that mole-like burrowing mammals existed already in the days of dinosaurs (for more details see the news. Analogs of modern moles, otters and primates existed already in the Jurassic period, "Elements", 02.16.2015).which means "precodont burrowing broad-fingered" (precodonts are an extinct group of primitive mammals). Dokofossor has specific traits that are characteristic of modern burrowing animals such as marsupial moles and golden moles. Dokofossor's paws are the paws of a specialized underground inhabitant. So now we know for sure that mole-like burrowing mammals existed already in the days of dinosaurs (for more details see the news. Analogs of modern moles, otters and primates existed already in the Jurassic period, "Elements", 02.16.2015).that mole-like burrowing mammals existed already in the time of dinosaurs (for more details see the news Analogs of modern moles, otters and primates existed already in the Jurassic period, "Elements", 16.02.2015).that mole-like burrowing mammals existed already in the time of dinosaurs (for more details see the news Analogs of modern moles, otters and primates existed already in the Jurassic period, "Elements", 16.02.2015).
In any case, the "mole" ecological form should have been quite rare, as it is now. It is also worth noting that dinosaurs, despite the external variety of forms, were generally an extremely conservative group, which changed little over time. Therefore, they were not very successful in the development of ecological niches. Dinosaurs did not manage to master the water layers (reptiles unrelated to them swam there: ichthyosaurs, plesiosaurs, mosasaurs), did not manage to enter the small size class and did not master the soil.
Anton Nelikhov