1) Fish genus 2) Genus acipenser 
Acipenser is genus of sturgeons. With 17 species, many of which are threatened, it is the largest genus in the order Acipenseriformes. ==Sources== ...
sturgeon
• (n.) A genus of ganoid fishes, including the sturgeons, having the body armed with bony scales, and the mouth on the under side of the head. See Sturgeon.
Ac`i·pen'ser noun [ Latin , the name of a fish.] (Zoology) A genus of ganoid fishes, including the sturgeons, having the body armed with bony scales, and the mouth on the under side of the head. See Sturgeon . 
The acipenser is a genus of cartilaginous ganoid fishes to which the sturgeon belongs.
[n] - type genus of the Acipenseridae: sturgeons
genus Acipenser noun type genus of the Acipenseridae: sturgeons