Banfiidae is a family of extinct

banffozoa Banffozoa (also called Heteromorphida) is an extinct class of bilaterians. Most workers place it in the Vetulicolia, but the protostome-like features of some members have motivated ongoing debate. Banffozoa consists of the order Banffiata (whi ...

n animals from North America and China. The family name is sometimes spelt Banffidae. It includes ''

Banffia ''Banffia'' is a genus of animals described from Middle Cambrian fossils. The genus commemorates Banff, Alberta, near where the first fossil specimens were discovered. Its placement in higher taxa is controversial, with it mostly being considere ...

'', ''

Heteromorphus ''Heteromorphus'' is an extinct genus of banffiid from the lower Cambrian Chengjiang lagerstatte. It contains one broadly accepted species, ''Heteromorphus confusus'', as well as a proposed junior synonym, ''Heteromorphus longicaudatus'' that ...

'', and possibly ''

Skeemella ''Skeemella'' is a genus of elongate animal from the Middle Cambrian Wheeler Shale and Marjum lagerstätte of Utah. It has been classified with the banffozoan vetulicolians. Description ''Skeemella'', which was first described in 2005, is d ...

''. The family may be

paraphyletic Paraphyly is a taxonomic term describing a grouping that consists of the grouping's last common ancestor and some but not all of its descendant lineages. The grouping is said to be paraphyletic ''with respect to'' the excluded subgroups. In co ...

. A ''Heteromorphus''-like dwarf "Form A" is allied with this group at the class level, but has not been formally described or assigned to this family.

Description

Banffiids have a bipartite body with a smooth anterior part that may or may not have a lateral groove, and a posterior part with many segments. Lateral pouches have not been seen, although some questions remain regarding their possible presence in ''Skeemella''. The entire body is twisted dextrally (from an anterior view). Gut diverticula may be present, but the structures interpreted as such could alternatively be a circulatory system. The anus is terminal, despite initial reports to the contrary in ''Heteromorphus''.

Distribution

Banffiids have been found across multiple paleocontinents, with ''Heteromporphus'' found in the

Chengjiang lagerstatte 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 organ ...

South China South China ( zh, s=, p=Huá'nán, j=jyut6 naam4) is a geographical and cultural region that covers the southernmost part of China. Its precise meaning varies with context. A notable feature of South China in comparison to the rest of China is ...

while ''Banffia'' has been found in the

Burgess Shale The Burgess Shale is a fossil-bearing deposit exposed in the Canadian Rockies of British Columbia, Canada. It is famous for the exceptional preservation of the soft parts of its fossils. At old (middle Cambrian), it is one of the earliest fos ...

and

Spence Shale The Spence Shale is the middle member of the Langston Formation in southeastern Idaho and northeastern Utah. It is exposed in the Bear River Range, the Wasatch Range and the Wellsville Mountains. It is known for its abundant Cambrian trilobite ...

of western

Laurentia Laurentia or the North American craton is a large continental craton that forms the Geology of North America, ancient geological core of North America. Many times in its past, Laurentia has been a separate continent, as it is now in the form of ...

. ''Skeemella'' has been found in the Pierson Cove and Marjum Formations, both above the

Wheeler Shale The Wheeler Shale (named by Charles Walcott) is a Cambrian ( 507 Ma) fossil locality world-famous for prolific agnostid and ''Elrathia kingii'' trilobite remains (even though many areas are barren of fossils) and represents a Konzent ...

and also in western Laurentia.

Taxonomy

The family Banffiidae and the class Banffozoa were proposed in a paper published in 2006, in order to contain ''

Banffia constricta ''Banffia'' is a genus of animals described from Middle Cambrian fossils. The genus commemorates Banff, Alberta, near where the first fossil specimens were discovered. Its placement in higher taxa is controversial, with it mostly being considere ...

'' in a redescription of that species, with ''Heteromorphus'' only mentioned as a possible home outside of Banffiidae for ''

Banffia confusa ''Heteromorphus'' is an extinct genus of Banffiidae, banffiid from the lower Cambrian Chengjiang lagerstatte. It contains one broadly accepted species, ''Heteromorphus confusus'', as well as a proposed junior synonym, ''Heteromorphus longicauda ...

''. A comprehensive phylogenetic revision in 2007 expanded Banffozoa to encompass the proposed class

Heteromorphida Banffozoa (also called Heteromorphida) is an extinct class of bilaterians. Most workers place it in the Vetulicolia, but the protostome-like features of some members have motivated ongoing debate. Banffozoa consists of the order Banffiata (whic ...

(which had excluded ''Banffia''), and placed ''Heteromorphus'' in the Banffiidae. It tentatively placed ''Skeemella'' outside of Banffiidae and the newly-erected order Banffiata, but under Banffozoa. "Form A", which had been included in the Heteromorphida, was not mentioned or reassigned. Two later sources have placed ''Skemella'' in Banffiidae while continuing to note doubts as to whether it is actually a vetulicolian. Banffozoans have been recognized as "rather different from vetulicolians proper," and proposed to be more closely related to

protostomes Protostomia () is the clade of animals once thought to be characterized by the formation of the organism's mouth before its anus during embryonic development. This nature has since been discovered to be extremely variable among Protostomia's memb ...

. However, multiple sources treat Banffozoa as part of Vetulicolia.

Cladograms

A 2024 study has found the Banffiidae to form the earliest part of the

stem Stem or STEM most commonly refers to: * Plant stem, a structural axis of a vascular plant * Stem group * Science, technology, engineering, and mathematics Stem or STEM can also refer to: Language and writing * Word stem, part of a word respon ...

-chordate

evolutionary grade A grade is a taxon united by a level of morphological or physiological complexity. The term was coined by British biologist Julian Huxley, to contrast with clade, a strictly phylogenetic unit. Phylogenetics The concept of evolutionary grades ...

, as shown in this simplified cladogram: An earlier study in 2014 placed vetulicolians as the sister-group of tunicates, but was unable to resolve any relationships among vetulicolians as a group:

References

Works cited

* * * * * * * * * * {{Taxonbar, from1=Q104852216 Vetulicolia Prehistoric chordate families