First in a series of posts on humanoid dinosaur races for D&D 5e.
Ability Score Increase: +2 Con and +2 Str (if it's good enough for dwarves, it's good enough for Stegomen).
Age: Stegomen count their age from the first ancestor in their racial memory. This makes no sense to non-stegomen.
Size: 7 ft tall when standing as straight as they can get. The tail, which is very flexible, is another 5 ft long.
Alignment: Stegomen are lawful, following the ways of their ancestors.
Speed: 25 ft.
Natural Armor: Stegomen cannot wear armor, but may use a shield. Their hide gives a natural AC of 14+Dex modifier. When they receive an ability score improvement from their class, they may instead raise their AC by 2, to a maximum of 20.
Tail: When only attacking with her thagomizer, a Stegoman's tail does 1d10 damage on a hit. It can also be used as an off-hand weapon for 1d4 damage. The regular weapon the Stegoman wields does not need to be a light weapon, but it does need to be one-handed.
About Stegomen: There are no sub-races of Stegomen, there are only Stegomen. Males and Females are indistinguishable to non-Stegomen. Subtle variations in the color of back plates clearly identifies sex to other Stegomen.