Below, you see a list with possible ichnogenera for an unlined (sub)horizontal, branched burrow with a cylindrical cross section and passive filling. Click on them to get detailed descriptions of the ichnogenus and a list of its ichnospecies. (Please allow for pop-up windows):

• Halimedides (Usually unbranched but may be branched; ichnogenus includes ornamented ichnospecies)
• Hormosiroidea (Usually unbranched but may be branched)
• Mixoteichichnus
• Omanichnus
• Scalaridomus
• Ubinia