Thalassinoides is an ichnogenus of trace fossil (fossil records of lifeforms' movement, rather than of the lifeforms themselves) used to refer to "dichotomously or T-branched boxworks, mazes and shafts, unlined and unornamented".^[1]: 179 Facies of Thalassinoides increased suddenly in abundance at the beginning of the Mesozoic.^[1]: 251 Such burrows are made by a number of organisms, including the sea anemone Cerianthus, Balanoglossus and fishes, but are most closely associated with decapod crustaceans of the (former) infraorder Thalassinidea.^[2]

Thalassinoides
Thalassinoides, burrows produced by thalassinideans, from the Middle Jurassic, Makhtesh Qatan, southern Israel
Trace fossil classification
Ichnogenus:	†ThalassinoidesEhrenberg, 1944 Gallery edit   Thalassinoides burrow system in the Sherborne Building Stone (Jurassic, Bajocian) of Dorset, England; slab cut parallel to bedding.   Thalassinoides burrow system in the Sherborne Building Stone (Jurassic, Bajocian) of Dorset, England; slab cut perpendicular to bedding.   Thalassinoides burrows give a unique texture to this crest carved from Ordovician Tyndall limestone. References edit ^ a b Richard Granville Bromley (1996). Trace Fossils: Biology, Taphonomy and Applications (2nd ed.). Routledge. ISBN 978-0-412-61480-4. ^ Paul M. Myrow (1995). "Thalassinoides and the enigma of Early Paleozoic open-framework burrow systems". PALAIOS. 10 (1): 58–74. Bibcode:1995Palai..10...58M. doi:10.2307/3515007. JSTOR 3515007. External links edit Chuck D. Howell's Ichnogenera Photos