Daza et al.. 2018 describe a privately-owned, Mid-Cretaceous, teeny-tiny, ‘enigmatic’ lizard preserved in amber, Barlochersaurus winhtini (Figs. 1, 3; 1.5 in total length). The authors report, “The fossil is one of the smallest and most complete Cretaceous lizards ever found, preserving both the articulated skeleton and remains of the muscular system and other soft tissues. Despite its completeness, its state of preservation obscures important diagnostic features.We determined its taxonomic allocation using two approaches: we used previously identified autapomorphies of squamates that were observable in the fossil; and we included the fossil in a large squamate morphological data set.”
FIgure 1. From Daza et al. 2018 and color overlays applied here.Phylogenetically the authors report,
“Results from the phylogenetic analysis places the fossil in one of four positions: as sister taxon of either Shinisaurus crocodilurus or Parasaniwa wyomingensis, at the root of Varanoidea, or in a polytomy with Varanoidea and a fossorial group retrieved in a previous assessment of squamate relationships.”
Unfortunately this lack of resolution is due to taxon exclusion.
In the large reptile tree (LRT, 1318 taxa; subset Fig. 2) Barlochersaurus nests between the stem snakes Pontosaurus (Fig. 5) and tiny Tetrapodophis (Figs. 3, 4) neither of which is listed in the text of the Daza et al. paper.
According to Wikipedia
“Anguimorpha include the anguids (alligator lizards, glass lizards, galliwasps and legless lizards). They are characterized by being heavily armored with non-overlapping scales, and almost all having well-developed ventrolateral folds (excluding Anguis). Anguidae members can, however, be somewhat difficult to identify in their family, as members can be limbed or limbless, and can be both viviparous and oviparous.” The LRT tests several anguids. They do not attract Barlochersaurus as well as Tetrapodophis and Pontosaurus.
(Fig. 5) has a longer tail and is much larger overall. The manus and pes of Pontosaurus are similar in proportion and detail to those of Barlochersaurus.
The Daza team printed 3D replicas,
blown up to 10 times the original size. These are publicly available at Florida’s Museum of Natural History and Harvard’s Museum of Comparative Zoology.
we looked at a more primitive pre-snake with legs (JKZ-Bu267) also found in amber here.
And, oh, yeah… did I forget to mention?
Phylogenetic miniaturization at the genesis of major and minor clades in the LRT strikes again! This time, to the extreme!
Daza JD, Bauer AM, Stanley EL, Bolet A, Dickson B and Losos JB 2018. A enigmatic miniaturized and attenuate whole lizard from the Mid-Cretaceous amber of Myanmar. Breviora 563: 18pp.