Scandensia is a key taxon at the base of the Squamata

Changes made December 04, 2014 to renest Scandensia basal to the Squamates, not the Lepidosauria.

From the Early Cretaceous of Spain, 
Scandensia has been described as “an unusual lizard” and “enigmatic.”

From Bolet and Evans 2011
“The original description of Scandensia (Evans and Barbadillo 1998) established that it was a squamate (e.g. jaw and tooth morphology, emarginated scapulocoracoid fenestrate clavicle, absence of gastralia) and this is confirmed by the new specimen (e.g. co-ossification of the pelvic bones, pubic morphology). The first phylogenetic analysis (Evans and Barbadillo 1998), using PAUP and a modified version of the Estes et al. (1988) matrix, put Scandensia in a basal position on the squamate stem.”

Figure 1. Scandensia a basal lepidosaur

Figure 1. Scandensia a basalmost squamate.

The present analysis confirms that nesting
Here Scandensia nests at the base of the Squamata, which means it was relic from the Early Permian living in the Early Cretaceous. Tendril-like fingers and toes mark it as arboreal.

The misnamed “Langobardisaurus” rossii, MFSN 19235, is the current larger outgroup taxon.

Figure 2. Langobardisaurus(?) rossii (MFSN 19235) reconstructed. Here it nests between basal sphenodontids and basal tritosaurs + squamates.

Figure 2. Langobardisaurus(?) rossii (MFSN 19235) reconstructed. Here it nests between basal sphenodontids and basal tritosaurs + squamates. Probably not a climber, but a digger.

There’s a whole other world of lepidosaurs being discovered that don’t fit into the established clades like the Sphenodontia and the Squamata. The Tritosauria are among them, but other clades, like the one that includes Scandensia and MFSN 19235, are out there and more should be expected.

References
Evans SE and Barbadillo LJ 1998. An unusual lizard (Reptilia: Squamata) from the Early Cretaceous of Las Hoyas, Spain. Zoological Journal of the Linnean Society 124:235-265.
Bolet A and Evans SE 2011. New material on the enigmatic Scandensia, an Early Cretaceous lizard from the Iberian Peninsula. Special Papers in Palaeontology 86:99-108.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s