''Thalassinoides'' is an

ichnogenus An ichnotaxon (plural ichnotaxa) is "a taxon based on the fossilized work of an organism", i.e. the non-human equivalent of an artifact. ''Ichnotaxon'' comes from the Ancient Greek (''íchnos'') meaning "track" and English , itself derived from ...

trace fossil A trace fossil, also called an ichnofossil (; ), is a fossil record of biological activity by lifeforms, but not the preserved remains of the organism itself. Trace fossils contrast with body fossils, which are the fossilized remains of part ...

(

fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserve ...

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". Facies of ''Thalassinoides'' increased suddenly in abundance at the beginning of the

Mesozoic The Mesozoic Era is the Era (geology), era of Earth's Geologic time scale, geological history, lasting from about , comprising the Triassic, Jurassic and Cretaceous Period (geology), Periods. It is characterized by the dominance of archosaurian r ...

. Such burrows are made by a number of organisms, including the

sea anemone Sea anemones ( ) are a group of predation, predatory marine invertebrates constituting the order (biology), order Actiniaria. Because of their colourful appearance, they are named after the ''Anemone'', a terrestrial flowering plant. Sea anemone ...

'' Cerianthus'', ''

Balanoglossus ''Balanoglossus'' is a genus of ocean-dwelling acorn worms. It has zoological importance because, being hemichordates, they are an "evolutionary link" between invertebrates and vertebrates. ''Balanoglossus'' specimens are deuterostomes, and r ...

'' and

fish A fish (: fish or fishes) is an aquatic animal, aquatic, Anamniotes, anamniotic, gill-bearing vertebrate animal with swimming fish fin, fins and craniate, a hard skull, but lacking limb (anatomy), limbs with digit (anatomy), digits. Fish can ...

es, but are most closely associated with

decapod The Decapoda or decapods, from Ancient Greek δεκάς (''dekás''), meaning "ten", and πούς (''poús''), meaning "foot", is a large order of crustaceans within the class Malacostraca, and includes crabs, lobsters, crayfish, shrimp, and p ...

crustacean Crustaceans (from Latin meaning: "those with shells" or "crusted ones") are invertebrate animals that constitute one group of arthropods that are traditionally a part of the subphylum Crustacea (), a large, diverse group of mainly aquatic arthrop ...

s of the (former) infraorder

Thalassinidea Thalassinidea is the former infraorder classification of decapod crustaceans that live in burrows in muddy bottoms of the world's oceans. In Australian English, the littoral thalassinidean '' Trypaea australiensis'' is referred to as the ''yabby'' ...

Gallery

Image:Sherborne Thalassinoides 2 large.jpg, ''Thalassinoides'' burrow system in the Sherborne Building Stone (Jurassic, Bajocian) of Dorset, England; slab cut parallel to bedding. Image:Sherborne Thalassinoides section large.jpg, ''Thalassinoides'' burrow system in the Sherborne Building Stone (Jurassic, Bajocian) of Dorset, England; slab cut perpendicular to bedding. Image:UofS Stone Crest.jpg, Thalassinoides burrows give a unique texture to this crest carved from

Ordovician The Ordovician ( ) is a geologic period and System (geology), system, the second of six periods of the Paleozoic Era (geology), Era, and the second of twelve periods of the Phanerozoic Eon (geology), Eon. The Ordovician spans 41.6 million years f ...

Tyndall limestone.

References

External links

Chuck D. Howell's Ichnogenera Photos
Arthropod trace fossils Vertebrate trace fossils Thalassinidea Paleozoic life of Manitoba {{trace-fossil-stub