Gallotia

The genus ''Gallotia'' are the lacertids (wall lizards) of the Canary Islands. This genus consists of a group that has been evolving there ever since the first islands emerged from the sea over 20 million years ago. The endemic species and subspecies of this group have a number of characteristics that make them quite special within their family (Lacertidae); their only close relatives are the sandrunner lizards ('' Psammodromus'') of the western Mediterranean region. ''Gallotia'' are characteristic for eating significant quantities of plants, and several lineages are often presented as classic examples for insular gigantism. However, a find of an even larger ''Gallotia'' species from the early Miocene of mainland Europe casts doubt on this assumption. Instead the ancestor of all modern ''Gallotia'' species of the Canary islands was probably already very large but carnivorous (Černaňský et al., 2016).

Systematics and biogeography

This genus can be broadly divided into two groups - lineages originating from the colonization of the earliest Canary Islands of Lanzarote, Fuerteventura and Gran Canaria, probably between 10-20 million years ago, and a lineage that colonised the younger western islands probably less than 10 million years ago (Cox et al., 2010). Both lineages contain large and small species.

MtDNA analyses indicate that Lanzarote and Fuerteventura were colonized first and this led to the small body-sized ''G. atlantica'' which is present today (Cox et al., 2010). Gran Canaria was the next island to have been colonized from Lanzarote/Fuerteventura, giving rise to the large body-sized species, ''G. stehlini'' (Cox et al., 2010). Finally, the clade that colonized the younger western islands was likely to have originated from Lanzarote/Fuerteventura. This western island clade diverged into two groups, all of which colonized Tenerife, La Palma, La Gomera and El Hierro, leading to 1) a medium-bodied (e.g., ''G. caesaris'' from El Hierro) and 2) a large bodied "giant" species (e.g., ''G. simonyi'' from El Hierro) on each of these islands (note that ''G. intermedia'' from Tenerife belongs to the "giant" group, but present-day individuals are not that large). The giant species now exist, at best, in small relict populations, while ''G. auritae'' may be extinct on La Palma.

Prehistoric remains were assigned to the taxa ''G. goliath'' and ''G. maxima'', the former supposedly occurring on several islands, the latter only on Tenerife. It was eventually determined, however, that ''G. maxima'' is a junior synonym of ''G. goliath'', and that the latter was very close to ''G. simonyi''; supposed ''G. goliath'' specimens from El Hierro, La Gomera, and La Palma are probably just extremely large individuals of, respectively, ''G. simonyi'', ''G. bravoana'', and ''G. auaritae'' (Barahona ''et al.'' 2000). However, a mummified giant specimen from Tenerife yielded ancient DNA remains, and by analysis of this, it was concluded that ''G. goliath'' is a valid species that probably was restricted to Tenerife, and apparently was closer to ''G. intermedia'' than to ''G. simonyi'' (Maca-Meyer ''et al.'' 2003).

Basal group
*''Gallotia atlantica'' - Atlantic lizard
**''Gallotia atlantica atlantica''
**''Gallotia atlantica mahoratae''
*''Gallotia stehlini'' - Gran Canaria giant lizard

Western clade

Large species
*'' Gallotia simonyi'' - Simony's lizard
**''Gallotia simonyi simonyi'' - Roque Chico de Salmor giant lizard, extinct (c.1930s)
**''Gallotia simonyi machadoi'' - El Hierro giant lizard
*''Gallotia bravoana'' - La Gomera giant lizard, formerly ''G. (simonyi) gomerana'' and ''G. simonyi bravoana'' (Miras & Pérez-Mellado 2005a)
*''Gallotia auaritae'' - La Palma giant lizard
*''Gallotia goliath'' - Tenerife giant lizard, subfossil; includes ''G. maxima''
*''Gallotia intermedia'' - Tenerife speckled lizard
Small species
*''Gallotia caesaris'' - Boettger's lizard
**''Gallotia caesaris caesaris''
**''Gallotia caesaris gomerae''
*''Gallotia galloti'' - Tenerife lizard or Western Canaries lizard
**''Gallotia galloti eisentrauti''
**''Gallotia galloti galloti''
**''Gallotia galloti insulanagae''
**''Gallotia galloti palmae''

References

* Barahona, F.; Evans, S. E.; Mateo, J.A.; García-Márquez, M. & López-Jurado, L.F. (2000): Endemism, gigantism and extinction in island lizards: the genus ''Gallotia'' on the Canary Islands. '' J. Zool.'' 250(3): 373-388. (HTML abstract)
* Černaňský A.; Klembara J.; Smith K.T. (2016): Fossil lizard from central Europe resolves the origin of large body size and herbivory in giant Canary Island lacertids '' Zool. J. Linn. Soc.,'' 167 (4) https://doi.org/10.1111/zoj.12340
* Cox, S. C.; Carranza S.; Brown R. P. (2010): Divergence times and colonization of the Canary Islands by ''Gallotia'' lizards. ''Molecular Phylogenetics & Evolution'' 56: 747-757.
* European Environment Agency (2006
European Nature Information System (EUNIS)
''Gallotia''. Downloaded on 18 May 2006.
* Filson, R.P. (2000)

Downloaded on 11 May 2006.
* Maca-Meyer, N.; Carranza, S.; Rando, J.C.; Arnold, E.N. & Cabrera, V.M. (2003): Status and relationships of the extinct giant Canary Island lizard ''Gallotia goliath'' (Reptilia: Lacertidae), assessed using ancient mtDNA from its mummified remains. '' Biol. J. Linn. Soc.'' 80(4): 659–670. (HTML abstract)
* Database entry includes a range map and a brief justification of why this species is listed as critically endangered
* Database entry includes a range map and justification for why this species is critically endangered
* Database entry includes a range map and justification for why this species is critically endangered
* Database entry includes a range map and justification for why this species is critically endangered

Footnotes

{{Taxonbar, from=Q1007776

Reptiles of the Canary Islands
Lizard genera
Taxa named by George Albert Boulenger