''Archotuba'' is a genus of elongated conical tubes that were seemingly deposited by colonial organisms. Known from the

Chengjiang Chengjiang (; earlier Tchinkiang) is a city located in Yuxi, Yunnan Province, China, just north of Fuxian Lake. Administrative divisions Chengjiang City has 2 subdistricts and 4 townships. ;2 subdistricts * Fenglu () * Longjie () ;4 towns C ...

, its biological affinity is uncertain; it somewhat resembles the tubes of the '

priapulid Priapulida (priapulid worms, from Gr. πριάπος, ''priāpos'' 'Priapus' + Lat. ''-ul-'', diminutive), sometimes referred to as penis worms, is a phylum of unsegmented marine worms. The name of the phylum relates to the Greek god of fertility ...

' ''

Selkirkia ''Selkirkia'' is a genus of predatory, tubicolous priapulid worms known from the Middle Cambrian Burgess Shale, Ogygopsis Shale, Puncoviscana Formation and the Early Ordovician Fezouata Formation. 142 specimens of ''Selkirkia'' are known from th ...

'', but a

cnidarian Cnidaria ( ) is a phylum under kingdom Animalia containing over 11,000 species of aquatic invertebrates found both in fresh water, freshwater and marine environments (predominantly the latter), including jellyfish, hydroid (zoology), hydroids, ...

affinity is also possible. In the absence of soft parts, there is insufficient data to confirm a biological affiliation.

''Archotuba elongata''

The extinct species ''Archotuba elongata'' is a debated priapulid from the

Early Cambrian The Cambrian ( ) is the first geological period of the Paleozoic Era, and the Phanerozoic Eon. The Cambrian lasted 51.95 million years from the end of the preceding Ediacaran period 538.8 Ma (million years ago) to the beginning of the Ordovic ...

, discovered by Luo and Hu in 1999. Recorded only in the

Chengjiang Biota The Maotianshan Shales () are a series of Early Cambrian sedimentary deposits in the Chiungchussu Formation or Heilinpu Formation, famous for their '' Konservat Lagerstätten'', deposits known for the exceptional preservation of fossilized orga ...

Yunnan Province Yunnan; is an inland Provinces of China, province in Southwestern China. The province spans approximately and has a population of 47.2 million (as of 2020). The capital of the province is Kunming. The province borders the Chinese provinces ...

, this species was initially found to be part of the phylum

Priapulida Priapulida (priapulid worms, from Gr. πριάπος, ''priāpos'' ' Priapus' + Lat. ''-ul-'', diminutive), sometimes referred to as penis worms, is a phylum of unsegmented marine worms. The name of the phylum relates to the Greek god of fertilit ...

, but some have raised the question that ''A. elongata'' may be related to the

cnidarians Cnidaria ( ) is a phylum under kingdom Animalia containing over 11,000 species of aquatic invertebrates found both in fresh water, freshwater and marine environments (predominantly the latter), including jellyfish, hydroid (zoology), hydroids, ...

. In fact, due to the lack of soft body preservation, not only does confusion remain as to the placement of ''A. elongata'', another described species, ''Archotuba conoidalis'', has been found to be a synonym of ''A. elongata''. The available specimens consist of hundreds of compressed tubes, white with some rust-colored blotches, each in shape a long cone at most 5 cm in length and 6 mm in width. The posterior is pointed, but save for a few rare annulations, the fossil is unadorned. The creature's intestine is visible along its midline, and its dark color may indicate a carnivorous nature. The habits of ''A. elongata'' are disputable: a popular explanation is that because this species is often found fixed to other creatures, and even clustered together with its own kind in similar orientations, it perhaps did not move, highly unlike the current understanding of priapulids. However, if indeed they were sedentary like the cnidarians, no tentacles have been preserved to support such a conjecture.

References

{{authority control Fossil taxa described in 1999 Enigmatic prehistoric animal genera