Hoburogekko

''Hoburogekko'' is an extinct genus of gecko that includes a single species, ''Hoburogekko suchanovi'', from the Early Cretaceous of Mongolia. It is known from two fossil specimens, one preserving the front part of the skull and the other preserving part of the lower jaw. ''Hoburogekko'' is one of four known Mesozoic geckos or gecko-like lizards, the others being ''Cretaceogekko'' from the Early Cretaceous of Burma, AMNH FR21444, an undescribed specimen from a slightly older deposit in Mongolia, and ''Gobekko'' from the Late Cretaceous of Mongolia. ''Hoburogekko'' is the third oldest known gecko behind AMNH FR21444 and ''Cretaceogekko''.

Description

The skull of ''Hoburogekko'' is short, blunt, and tall. The proportions of its skull bones are similar to those of the living genus ''Bunopus'', although the two are not closely related. The general appearance of ''Hoburogekko'' resembles that of the living species ''Agamura persica'', ''Bunopus tuberculatus'', ''Pristurus carteri'', ''Ptenopus carpi'', and '' Teratoscincus przewalskii'', all of which have blunt and tall snouts. Most of these species live on the ground and inhabit desert regions. ''Hoburogekko'' probably had a similar lifestyle, fitting with sedimentological evidence that the region of Mongolia in which it was found was semi-arid during the Early Cretaceous. By comparison with living blunt-snouted, desert-dwelling geckos, ''Hoburogekko'' may have had a cylindrical body adapted for a burrowing lifestyle.

The total length of the skull of ''Hoburogekko'' is estimated to be . The total body length of ''Hoburogekko'' difficult to extrapolate from its skull alone because the relative size of the head to the rest of the body varies greatly among living geckos. Based on this range of proportions, ''Hoburogekko'' may have been anywhere between long. ''Hoburogekko'' appears primitive in having an open Meckelian groove beneath the eye socket, but it is similar to living geckos in having a frontal bone that forms a tube along the midline of the skull. Other derived features of geckos possessed by ''Hoburogekko'' include smooth skull bones. Another derived gekkotan characteristic, eye sockets that are not bounded in the back by postorbital bars, may have been present in ''Hoburogekko'', although only the front portion of the eye socket is preserved in the known specimens of ''Hoburogekko''. The large size of the jugal bone suggests that it may have extended backward to form a postorbital bar, in which case ''Hoburogekko'' would appear more primitive.

Relationships

''Hoburogekko'' was recognized as a close relative of geckos since it was first named in 1989. However, a paucity of distinguishing characteristics in the two known specimens of ''Hoburogekko'' meant that its evolutionary relationships were not evaluated in a phylogenetic analysis until many years after its first description. The phylogenetic analysis of Daza ''et al.'' (2012) found ''Hoburogekko'' to be closely related to the living species '' Phyllurus platurus'', commonly called the broad-tailed gecko. In the analysis, ''Hoburogekko'' and ''Phyllurus'' are more closely related to the legless pygopodids than they are to most other geckos, burt this position need to be re-evaluated, including more members of the crown group Gekkota. The analysis also included ''Norellius nyctisaurops'' and ''Gobekko'' and placed them outside Gekkota, the group that includes true geckos, as more basal members of the larger group Gekkonomorpha. Therefore, ''Hoburogekko'' may be the most derived of the four known Mesozoic gekkonomorphs. However, the analysis of Daza ''et al.'' (2013) placed ''Hoburogekko'' in a polytomy or unresolved evolutionary relationship with ''Gobekko'', ''P. platurus'' (representing the family Carphodactylidae), pygopodids, and a clade (evolutionary grouping) including all other geckos, meaning that its position within Gekkonomorpha is still uncertain.

References

{{Taxonbar, from=Q14610664

Geckos
Cretaceous lizards
Fossils of Mongolia