Aenigmacarididae Aratidecthidae Kallidecthidae Aeschronectida is an extinct order of mantis shrimp-like crustaceans which lived in the Mississippian subperiod in what is now Montana.

[5] Aeschronectida have typical characteristics of hoplocarids including 3-flagellate first antenna, an enlarged abdomen, a shortened thorax, 3-segmented thoracic protopods, cephalic kinesis, pleopodal epipodite gills, and an articulated rostrum.

They differ from typical hoplocarids by having their carapace covering the entire thorax and the unspecialized thoracopods acting as natatory appendages[6] Like the Mantis Shrimp, their eyes are stalked and elevated on the anterior cephalon.

Class: Malacostraca Subclass: Hoplocarida Families & Genera Aeschronectids are particularly hard to identify due to their fossils being damaged or half-digested.

[10] Many studies involving Aeschronectids generally try and distinguish new families and Genera or try and connect them as potential predecessors to Stomatopoda.