Lower Sakamena Formation

The environment of the formation is thought to have been warm and humid with a temperate climate, with rainfall likely being seasonal and possibly monsoonal, with the immediate area surrounding the lakes likely being a riparian forest in which Glossopteris trees were likely a prominent component. The lower waters of the lakes within the rift system are likely to have been cold and anoxic (oxygen depleted), which helped to preserve animal remains by slowing decay. The articulated animal remains are suggested to largely have originated from mass mortality events when during heavily rain and floods, the anoxic waters in the lower part of the lakes became mixed with those in the upper part, killing aquatic animals as a result of oxygen deprivation in the case of fish or thermal shock. Articulated remains of terrestrial vertebrates were probably were washed in postmortem rather than being killed by the anoxic water.^[2][3]

After Smith (2000):^[2]

Vertebrates of the Lower Sakamena Formation
Genus	Note	Images
Claudiosaurus	A probably aquatic neodiapsid reptile
Hovasaurus	An aquatic tangasaurid neodiapsid reptile
Barasaurus	An owenettid procolophonian non-diapsid reptile
Coelurosauravus	A gliding weigeltisaurid neodiapsid reptile
Thadeosaurus	A probably terrestrial tangasaurid neodiapsid reptile
Acerosodontosaurus	A probably aquatic tangasaurid neodiapsid reptile
Oudenodon	A dicynodont therapsid known from a skull. Other indeterminate postcranial dicynodont remains are also known from the formation
Atherstonia	A "palaeoniscoid"-grade ray-finned fish
Rhinesuchidae indet	Temnospondyl amphibians known from fragmentary remains
Theriodontia indet	An indeterminate therapsid known from a lower jaw