Synapsids of the Night Below

The success and proliferation of Synapsids in the Night Below's underground environment can be attributed to a combination of their unique adaptations and the absence of significant competitors. Below are some key factors that might have contributed to the thriving presence of Synapsids in this subterranean world:
Niche Filling: Synapsids, with their repto-mammalian characteristics, found ecological niches in the Night Below that were unoccupied or underserved. Their adaptations allowed them to exploit specific roles within the ecosystem, filling gaps in the food chain and resource utilization.
Evolutionary Advantage: Over time, the Synapsids' adaptations have provided them with distinct advantages in the underground environment. Thermoregulation mechanisms, and sensory adaptations have given them an edge in survival, breeding success, and resource acquisition.
Lack of Competitors: The Night Below's unique conditions and absence of certain surface-dwelling species might have led to an environment with fewer or no direct competitors for Synapsids. This lack of rivalry would have allowed them to diversify and specialize in various ecological roles.
Ecosystem Engineering: As adaptable and diverse organisms, Synapsids might have inadvertently contributed to the shaping and stability of the Night Below's ecosystems. Their activities, such as feeding, burrowing, or scavenging, could have influenced nutrient cycling, soil structure, and other factors that create a favorable environment for their proliferation.
Synergistic Adaptations: Synapsids' various subspecies and adaptations could have formed a complex web of interactions that contributed to their success. For example, one subspecies's behavior might benefit another's survival or resource availability, fostering a mutually reinforcing ecosystem.
Geological Stability: The relatively consistent underground temperature and sheltered environment might have provided stability and predictability for Synapsids compared to the surface world, where weather and environmental changes are more dramatic.
Evolutionary Opportunity: The Night Below could have presented a unique set of selective pressures and challenges that favored the evolution of certain traits in Synapsids. These adaptations could have allowed them to exploit the available resources and niches in the underground biome.