''Blattoidealestes'' is a dubious

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 ...

therocephalia Therocephalia is an extinct clade of therapsids (mammals and their close extinct relatives) from the Permian and Triassic periods. The therocephalians ("beast-heads") are named after their large skulls, which, along with the structure of their te ...

n, an

extinct Extinction is the termination of an organism by the death of its Endling, last member. A taxon may become Functional extinction, functionally extinct before the death of its last member if it loses the capacity to Reproduction, reproduce and ...

therapsid from the

Middle Permian The Guadalupian is the second and middle series/epoch of the Permian. The Guadalupian was preceded by the Cisuralian and followed by the Lopingian. It is named after the Guadalupe Mountains of New Mexico and Texas, and dates between 272.95 ± 0. ...

South Africa South Africa, officially the Republic of South Africa (RSA), is the Southern Africa, southernmost country in Africa. Its Provinces of South Africa, nine provinces are bounded to the south by of coastline that stretches along the Atlantic O ...

. The

type species In International_Code_of_Zoological_Nomenclature, zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the spe ...

''Blattoidealestes gracilis'' was named by South African paleontologist Lieuwe Dirk Boonstra from the ''Tapinocephalus'' Assemblage Zone in 1954. Dating back to the Middle Permian, ''Blattoidealestes'' is one of the oldest therocephalians. It is similar in appearance to the small therocephalian '' Perplexisaurus'' from Russia, and may be closely related. Blattoidealestes block

The

holotype A holotype (Latin: ''holotypus'') is a single physical example (or illustration) of an organism used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of s ...

specimen of ''Blattoidealestes'' was discovered in 1918 in Prince Albert, Western Cape and cataloged as SAM 4321. SAM 4321 consists of a skull and partial postcranial skeleton. At around , the skull is extremely small for a therocephalian. It was heavily distorted during fossilization and preparation, with the right side heavily eroded and most of the skull having been broken off from the main block. The snout is short and the eye sockets are very large. The lower jaw is slender, with a projection called the coronoid process very prominent. The skull bears many small teeth, including a pair of canines in the upper and lower jaws. Each postcanine tooth has lateral grooves on its surface, creating several small cusps. Cuspid teeth are common in

Late Permian Late or LATE may refer to: Everyday usage * Tardy, or late, not being on time * Late (or the late) may refer to a person who is dead Music * ''Late'' (The 77s album), 2000 * Late (Alvin Batiste album), 1993 * Late!, a pseudonym used by Dave Groh ...

and Triassic therocephalians, and the closely related cynodonts, which are the ancestors of mammals, but no earlier theriodont possesses this type of tooth. Therefore, ''Blattoidealestes'' represents the oldest record of multicuspid teeth among

theriodont The theriodonts (clade Theriodontia) are a major group of therapsids which appeared during the Middle Permian and which includes the gorgonopsians and the eutheriodonts, itself including the therocephalians and the cynodonts. Naming In 1876, ...

s. Although it is one of the earliest members of the group, ''Blattoidealestes'' was initially thought to be in a derived position among therocephalians. Due to its small size, ''Blattoidealestes'' was originally classified with other tiny therocephalians in a group called Scaloposauria. Scaloposauria has fallen out of use in recent years, and is now thought to represent a

polyphyletic A polyphyletic group is an assemblage that includes organisms with mixed evolutionary origin but does not include their most recent common ancestor. The term is often applied to groups that share similar features known as Homoplasy, homoplasies ...

assemblage of juvenile therocephalians. Along with many other small-bodied "scaloposaurians", ''Blattoidealestes'' was later classified as a member of the advanced therocephalian

clade In biology, a clade (), also known as a Monophyly, monophyletic group or natural group, is a group of organisms that is composed of a common ancestor and all of its descendants. Clades are the fundamental unit of cladistics, a modern approach t ...

Baurioidea. A revision of this specimen in 2023 determined that ''Blattoidealestes'' instead represents a juvenile scylacosaurid, one of the earliest divering clades of therocephalians. It is identifiable as an early therocephalian rather than a baurioid by having serrated canines, and its snout proportions identify it specifically as a scylacosaurid.

References

{{Taxonbar, from=Q4925526 Guadalupian synapsids of Africa Scylacosauridae Guadalupian synapsids Guadalupian genus first appearances Guadalupian genus extinctions