Adriosaurus suessi (Seeley 1881) Late Cretaceous, ~95 mya, ~25 cm, wasn't a snake, but a close sister taxon. Derived from a sister to Ardeosaurus and Jucaraseps, Adriosaurus was a phylogenetic predecessor to the snake Pachyrhachis.

Distinct from Ardeosaurus, the skull of Adriosaurus was longer, as were the nares and nasals and premaxillary process. The postfrontal/postorbital contacted the prefrontal. The frontal and parietal were narrower. The sqauamosal was shorter. The teeth were longer. The coronoid process was taller.

The cervicals were smaller and more numerous as were the dorsals and caudals. The ribs were thicker (pachystotic). The dorsal ribs were shorter producing a more snake-like body.

The ilium was taller. The limbs were shorter. The metatarsals were subequal.

Various specimens of Adriosaurus documenting forelimb loss from Palci and Caldwell 2007.

Pontosaurus lesinensis (Gorjanovic-Kramberger 1892; Caldwell 2006) was a larger sister to Adriosaurus with a longer, deeper tail and phylogenetically closer to snakes.

Primitivus manduriensis (Paparella, Palci, Nicosia and Caldwell 2018; Late Cretaceous) was originally considered cose to dolichosaurs and mosasaurs. Here it nests with Pontosaurus.

Dolichosaurus longicollis (Owen 1850, Caldwell 2000) was a smaller sister to Pontosaurus with a shorter, shallower tail, closer to the proportions in snakes. The limbs were shorter, the neck was longer, up to 19 cervicals. Known from several specimens, two of which may represent the front and mid-portions of the skeleton.

Caldwell MW 1999. Description and phylogenetic relationships of a new species of Coniasaurus Owen, 1850 (Squamata). Journal of Vertebrate Paleontology 19:438-455.

Caldwell MW 2000. On the aquatic squamate Dolichosaurus longicollis Owen, 1850 (Cenomian, Upper Cretaceous) and the evolution of elongate necks in Squamates. Journal of Vertebrate Paleontology 20(4):720-735.

Caldwell MW and Cooper JA 1999. Redescription, palaeobiogeography and palaeoecology of Coniasaurus crassidens Owen, 1850 (Squamata) from the Lower Chalk (Cretaceous; Cenomanian) of SE England. Zoological Journal of the Linnean Society 127:423-452.

Caldwell MW 2006. A new species of Pontosaurus (Squamata, Pythonomorpha) from the Upper Cretaceous of Lebanon and a phylogenetic analysis of Pythonomorpha. Memorie della Società Italiana di Scienze Naturali e del Museo Civico di Storia Naturale di Milano 34: 1–42.

Caldwell MW and Palci A 2010. A new species of marine ophidiomorph lizard, Adriosaurus skrbinensis, from the Upper Cretaceous of Slovenia. Journal of Vertebrate Paleontology 30(3): 747-755. doi:10.1080/02724631003762963.

Gorjanovic-Kramberge D 1892. O fosilnih cetaceih hrvatske i kranjske. Rad. Jugoslavenske Akademije Znanosti i Umjetnosti 111:1-21.

Owen R 1850. Description of the fossil reptiles of the Chalk Formation: pp. 378-404 in F. Dixon (ed) The geology and fossils of the Tertiary and Cretaceous Formations of Sussex. Longman, Brown, Green and Longman, London.

Palci A and Caldwell MW 2007. Vestigial forelimbs and axial elongation in a 95 million-year-old non-snake squamate. Journal of Vertebrate Paleontology 27 (1): 1-7.

Paparella I, Palci A, Nicosia U and Caldwell MW 2018. A new fossil marine lizard with soft tissues from the Late Cretaceous of southern Italy. Royal Society Open Science 5: 172411. http://dx.doi.org/10.1098/rsos.172411

Pierce SE and Caldwell MW 2004. Redescription and phylogenetic position of the Adriatic (Upper Cretaceous; Cenomanian) dolichosaur Pontosaurus lesinensis (Kornhuber, 1873). Journal of Vertebrate Paleontology 2:373-386.

Seeley HG 1881. On remains of a small lizard from Neocomian rocks of Comen, near Trieste, preserved in the Geological Museum of the University of Vienna. Quarterly Journal of the Geological Society of London 37: 52-56.

wiki/Adriosaurus
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