''Elfridia'' is a poorly known 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 ...

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 ...

Gymnarthridae Gymnarthridae is an extinct family of tuditanomorph microsaurs. Gymnarthrids are known from Europe and North America and existed from the Late Carboniferous through the Early Permian. Remains have been found from the Czech Republic, Nova Scotia, ...

History of study

''Elfridia'' was named in 1985 by American paleontologist David Thayer based on material collected from

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 ...

exposures of the

Swisshelm Mountains The Swisshelm Mountains are a small mountain range adjacent to the southwest corner of the Chiricahua Mountains of eastern Cochise County, Arizona. They are separated from the Pedrogosa Mountains to the southeast, the Chiricahuas to the northea ...

in Arizona. The genus name is derived from the nearby town of

Elfridia ''Elfridia'' is a poorly known extinct genus of microsaur within the family Gymnarthridae. History of study ''Elfridia'' was named in 1985 by American paleontologist David Thayer based on material collected from Carboniferous exposures of the ...

, and the species name, ''E. bulbidens,'' is with respect to the bulbous teeth of the animal (''bulbi-'' for 'bulbous' and ''-dens'' for 'tooth'). It is one of the oldest known 'microsaurs' and one of the few from the American southwest region.

Anatomy

The holotype of ''Elfridia'' is a left mandible. Several other tooth-bearing fragments and isolated postcranial elements are assigned to this taxon. It is diagnosed by having lingually recurved tips of the teeth that are positioned asymmetrically on the labial portion. There are nine to ten teeth on the mandible with a greatly enlarged tooth along the mid-length of the tooth row.

Relationships

Thayer placed ''Elridia'' within the

, but the fragmentary nature of the material has precluded its incorporation into a phylogenetic analysis to more thoroughly test and to evaluate its relationships with other 'microsaurs.' He compared it to both ''

Euryodus ''Euryodus'' is an extinct genus of microsaur within the family Gymnarthridae. References See also * Prehistoric amphibian * List of prehistoric amphibians This list of prehistoric amphibians is an attempt to create a comprehensive listing ...

'' and ''

Cardiocephalus ''Cardiocephalus'' is an extinct genus of lepospondyl amphibian from the Permian period. It was a member of the family Gymnarthridae Gymnarthridae is an extinct family of tuditanomorph microsaurs. Gymnarthrids are known from Europe and North ...

'', noting a mixture of features shared between the two gymnarthrids, such as the enlarged tooth (shared with ''Euryodus primus'') and striations on the teeth (shared with ''Cardiocephalus'').

References

Gymnarthrids {{Lepospondyli-stub