In a world where the KT event didn't happen, all bets truly are off. Even in the placid climate of the Paleocene - just before the Eocene Thermal Maximum and its ensuing turnover, long before the drastic changes of the Cenozoic - entire biotas were...
Dinosaur, Speculative evolution
In the Late Cretaceous a lineage of deltatheroidean metatherians developed specialised, tightly packed hairs with branching filaments, superficially similar to plumes. This permitted an unique development in vertebrate history: by extending these hairs...
Speculative biology, Speculative evolution
Mammals
Tyrannotherium rex: A twelve meter long, 15 ton heavy gobiconodontid.
Napioa piadaph: A grizzly sized gobiconodontid.
Napioa leonina A polar bear sized gobiconodontid.
Circavelocipterus major: A 2 meter wingspanned volaticothere.
...
Speculative, Speculative evolution, biology, evolution
A speculative evolution exercise
in an alternate timeline two lineages of placoderms convergent with syngnathid fish evolved:
- longmaiformes were a clade of arthrodires of uncertain affinities as they more or less appear in the mid-devonian fossil
Placoderm, Speculative biology, Speculative evolution, seahorse
-881293748 "speculative evolution: feathered mammal concepts by inmyarmsinmyarms")
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Another speculative evolution musing
non-placental mammals are faced with an unique predicament. possessing epipubic bones, they cannot expand their torsos, and thus cannot give birth to complex, well developed young you take for granted.
Speculative, Zoology, biology, evolution, monotreme