A Bogosrin resembled a Terran bear adorned with gazelle-like horns on its head. They were larger and physically stronger than Linnik. They had male and female sexes. Females were larger, sturdier and usually walked on all four legs. (TOS novel: The Face of the Unknown)
Thousands of years ago, the Bogosrin were avid engineers and built Bogosrin space stations in Cherela's atmosphere. They were a pre-warp civilization when the Tessegri arrived to establish first contact. Initially enjoying the mutually beneficial relationship, the Tessegri became greedy and pushy, and war erupted between the two species.
Then the Dassik arrived and enslaved both species under the Dassik nation. The Dassik's first slave race, the Linnik, fomented an alliance between the Bogosrin, Tessegri and Kisaja. Over time, this alliance evolved into the First Federation.
Twelve millennia before the 23rd century, the Dassik subjected worlds of the sector to planetary bombardment. By then, the Bogosrin homeworld was only one of several homes for the Bogosrin. The Bogosrin constructed the Web of Worlds, based on Linnik design, beneath the clouds of Cherela, and it became a sanctuary for the alliance's survivors.