They can be differentiated from the Dendrobranchiata prawns by their lack of branchinggills, and by the fact that they brood their eggs instead of directly releasing them into the water. They differ from the Caridea shrimp by their greatly enlarged third pair of legs.[2]
There are 71 extant species currently recognized within Stenopodidea, divided into 12 genera.[4] Three fossil species are also recognized, each belonging to a separate genus.[5][6] The earliest fossil assigned to the Stenopodidea isDevonostenopus pennsylvaniensis from theDevonian.[6] UntilD. pennsylvaniensis was discovered, the oldest known member of the group wasJilinicaris chinensis from theLate Cretaceous.[7]
The cladogram below shows Stenopodidea's internal relationships:[3]
^abWade T. Jones; Rodney M. Feldmann; Carrie E. Schweitzer; Frederick R. Schram; Rose-Anna Behr & Kristen L. Hand (2014). "The first Paleozoic stenopodidean from the Huntley Mountain Formation (Devonian–Carboniferous), north-central Pennsylvania".Journal of Paleontology.88 (6):1251–1256.doi:10.1666/13-059.
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