Identification key for Atlantic Acarnus spp
1- Acanthostyles present.................................................................................. 2
- Acanthostyles absent.................................................................................. 6
2- Acanthoxeas present................................................................. A. microxeatus sp. nov.
- Acanthoxeas absent................................................................................... 3
3- Only a single category of cladotylotes present............................................................... 4
- Two categories of cladotylotes present..................................................................... 5
4- Only a single category of acanthostyles present...................................................... A. radovani
- Two categories of acanthostyles present............................................................ A. souriei
5- Two categories of toxas........................................................................... A. levii
- Three categories of toxas....................................................................... A. nicoleae
6- Styles with a smooth base; larger cladotylotes with a smooth shaft................................... A. innominatus
- Styles with microspined or rugose base; two categories of microspined cladotylotes................................. 7
7- Two categories of cladotylotes........................................................................... 8
- Three categories of cladotylotes............................................................... A. deweerdtae
8- Three categories of toxas............................................................................... 9
- Two categories of toxas......................................................................... A. tortillis
9- Cladotylotes I with basal tyle flattened and provided with lobes and blunt protrusions........................ A. claudei
- Cladotylotes I with basal tyle bearing curved spines................................................... A. toxeata