''Asaphestera'' is an extinct

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

of a

synapsid Synapsida is a diverse group of tetrapod vertebrates that includes all mammals and their extinct relatives. It is one of the two major clades of the group Amniota, the other being the more diverse group Sauropsida (which includes all extant rept ...

described on the basis of fossils from the

Carboniferous The Carboniferous ( ) is a Geologic time scale, geologic period and System (stratigraphy), system of the Paleozoic era (geology), era that spans 60 million years, from the end of the Devonian Period Ma (million years ago) to the beginning of the ...

of the Joggins locality in

Nova Scotia, Canada Nova Scotia is a Provinces and territories of Canada, province of Canada, located on its east coast. It is one of the three Maritime Canada, Maritime provinces and Population of Canada by province and territory, most populous province in Atlan ...

. It was originally described as an undetermined

lepospondyl Lepospondyli is a diverse clade of early tetrapods. With the exception of one late-surviving lepospondyl from the Late Permian of Morocco ('' Diplocaulus minimus''), lepospondyls lived from the Visean stage of the Early Carboniferous to the Earl ...

and subsequently classified as a microsaur within the

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Tuditanidae Tuditanidae is an extinct family (biology), family of microsaurian tetrapods. Fossils have been found from Nova Scotia, Ohio, and the Czech Republic and are Late Carboniferous in age. Tuditanids were medium-sized terrestrial microsaurs that rese ...

. A study published in 2020 found that specimens referred to ''Asaphestera'' represented several unrelated species. Steen (1934)'s original species name ''Asaphestera platyris'' was retained for a skull which has been re-evaluated as the earliest known

. The type species of ''Asaphestera'' is ''Asaphestera platyris'', named by Steen (1934) based on three skulls. Carroll & Gaskill (1978) noted that one of the skulls was briefly named as the species ''" Hylerpeton" intermedium'' by Dawson (1894), though it is no longer consider related to the genus ''Hylerpeton''. According to Dawson's species name, they renamed ''Asaphestera platyris'' to ''Asaphestera intermedia''. Mann ''et al.'' (2020) re-evaluated purported Joggins microsaurs and found several unusual results. One of the skulls assigned the name ''Asaphestera platyris'' by Steen appeared to be a valid taxon, but instead of a microsaur it was the oldest known synapsid, possibly an eothyridid. Dawson's ''"Hylerpeton" intermedium'' was determined to be an indeterminate tetrapod and a ''

nomen dubium In binomial nomenclature, a ''nomen dubium'' (Latin for "doubtful name", plural ''nomina dubia'') is a scientific name that is of unknown or doubtful application. Zoology In case of a ''nomen dubium,'' it may be impossible to determine whether a ...

''. Additional ''Asaphestera'' material was named as a new genus of microsaur, '' Steenerpeton''. Scales are preserved in the type specimen of ''A. platyris'', which are also observed in other early synapsids.

References

Prehistoric synapsid genera Paleozoic life of Nova Scotia Fossil taxa described in 1934 {{paleo-synapsid-stub