Sanajeh

Sanajeh (meaning "ancient gape" in Sanskrit)[1] is a genus of late Cretaceous madtsoiid snake from western India. A recently described fossil from the Lameta Formation has been found coiled around an egg and an adjacent skeleton of a 50 cm long sauropod dinosaur hatchling. This suggests that the snake preyed on hatchling sauropods at nesting sites.

Description
The holotype specimen, known as GSI/GC/2901–2906, consists of a nearly complete skull and lower jaws, and 72 precloacal vertebrae and ribs preserved in five articulated sections. It was found from Maastrichtian-age calcareous sandstones outcropping in the village of Dholi Dungri in Gujarat.

Sanajeh was around 3.5 metres (11 ft) in length based on the length of the skull, which is 95 millimetres (3.7 in). On the side of the skull there is an opening called the juxtastapedial recess, which is characteristically rectangular. The juxtastapedial recess would have contained cranial nerves associated with the ear, while another opening located in front of the recess, the trigeminal foramen, housed cranial nerves associated with the jaws. The jaw joint of Sanajeh is located to the side of the posterior margin of the braincase, which is characteristic of basal snakes. A sagittal crest runs along the ventral surface of the braincase and served as an attachment for protractor pterygoidei muscles that moved the toothed bones of the palate.[2]

Articulations between the vertebrae are well developed in Sanajeh in a similar way to other madtsoiids and the genus Najash. The neural spines are thin and angled posteriorly. In Sanajeh, the synapophyses, or rib articulations, extend outward past the margins of the prezygapophyses. This is a characteristic of all madtsoiids.

Classification
Sanajeh is a member of the Madtsoiidae, an extinct family of snakes that includes the Australian genera Wonambi and Yurlunggur. Below is a cladogram[4] showing the phylogenetic relations of Sanajeh: