No

Not much is known about the Megazostrodon but what is known is that it was probably an omnivore. Chances are, it was hunted by carnivorous dinosaurs and larger reptiles.

There is some debate about this, actually. No one really knows for sure what the first mammal was, but there are two top contenders for the title: the Megazostrodon and the Morganucodon. Both are believed to have lived around 200 million years ago and the species are closely related.

In the water: many of the same types of animals we see today in the waters (though not the same species): fish, shellfish, corals, etc. On land: archosaurs (reptile ancestors of dinosaurs), synapsid reptiles (reptile ancestors of mammals), lizards, crocodiles, and eventually dinosaurs, pterosaurs and mammals.

Plant life included cycads, ferns, ginkos and conifers. (There were no deciduous trees, grass, or flowering plants.)