Metacarcinus minutoserratus is an extinct crab from the family Cancridae, which is known for its robust, often rounded carapaces.

This species was described based on fossil evidence and is thought to have lived during the Pliocene epoch.

[1] It was first discovered by Japanese biologist Hideki Nagamori in 1940 "from a cliff outcrop of the right bank of the Himekawa River near Miyamoto, Otari Village, Kita-azumi County, Nagano Prefecture, central Japan.

"[2]