Iphthiminus serratus is a species of darkling beetles in the subfamily Tenebrioninae.

[1][2] Originally I. sublaevis and I. salebrosus were considered subspecies of I. serratus due to minor geographical variation, but this variation is gradual and they are now considered synonyms.

[3] This species is present primarily in the western North America, including California, Idaho, Nebraska, Nevada, New Mexico, Oregon, Washington, Wyoming, and British Columbia.

[3] Like other darkling beetles in the genus Iphthiminus, I. serratus is associated with rotting coniferous logs, especially pine wood.

[3] When raised in captivity by the Invertebrate Dude, I. serratus was observed eating chick feed and rotting wood.