''Asaphestera'' is an extinct

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

of a

tetrapod Tetrapods (; ) are four-limbed vertebrate animals constituting the superclass Tetrapoda (). It includes extant and extinct amphibians, sauropsids ( reptiles, including dinosaurs and therefore birds) and synapsids (pelycosaurs, extinct theraps ...

described on the basis of fossils from the

Carboniferous The Carboniferous ( ) is a geologic period and system of the Paleozoic that spans 60 million years from the end of the Devonian Period million years ago ( Mya), to the beginning of the Permian Period, million years ago. The name ''Carbonifero ...

of the

Joggins Joggins is a rural community located in western Cumberland County, Nova Scotia, Canada. On July 7, 2008 a 15-km length of the coast constituting the Joggins Fossil Cliffs was officially inscribed on the World Heritage List.p39 Other organisms fo ...

locality in

Nova Scotia, Canada Nova Scotia ( ; ; ) is one of the thirteen provinces and territories of Canada. It is one of the three Maritime provinces and one of the four Atlantic provinces. Nova Scotia is Latin for "New Scotland". Most of the population are native Engl ...

. It was originally described as an undetermined

lepospondyl Lepospondyli is a diverse taxon of early tetrapods. With the exception of one late-surviving lepospondyl from the Late Permian of Morocco (''Diplocaulus minumus''), lepospondyls lived from the Early Carboniferous ( Mississippian) to the Early Per ...

and subsequently classified as a

microsaur Microsauria ("small lizards") is an extinct, possibly polyphyletic order of tetrapods from the late Carboniferous and early Permian periods. It is the most diverse and species-rich group of lepospondyls. Recently, Microsauria has been considere ...

within the

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

Tuditanidae Tuditanidae is an extinct family of tuditanomorph microsaurs. 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 resembled lizards. ...

. A study published in May 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

synapsid Synapsids + (, 'arch') > () "having a fused arch"; synonymous with ''theropsids'' (Greek, "beast-face") are one of the two major groups of animals that evolved from basal amniotes, the other being the sauropsids, the group that includes reptil ...

. 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 ''Hylerpeton'' is an extinct genus of leponspondyl amphibian belonging to the family Gymnarthridae from the late Carboniferous period. The nominal species ''"Hylerpeton" longidentatum'' Dawson, 1876 was considered possibly non-microsaurian by ...

" 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 s ...

''. Additional ''Asaphestera'' material was named as a new genus of microsaur, '' Steenerpeton''.

References

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