Mauriciosaurus bore 21 cervical vertebrae, at least 23 thoracic vertebrae, and at least 25 in the sacrum and tail (the delineation between these two types is not clear, since it is obscured by the ischium).
The centra of Mauriciosaurus are constricted on their outer surfaces, unlike the cylindrical centra of Trinacromerum.
Both the cervical and thoracic centra have length-width ratios of about 2:3; the cervical centra are procoelous (concave in front and convex behind), whereas the thoracic centra are platycoelous (both surfaces are flat).
The sacral and caudal centra are generally shorter, with length-width ratios of about 1:3, but they also become narrower such that the last several preserved caudal centra are twice as long as they are wide; the first caudal centrum appears to be opisthocoelous (convex in front and concave behind), while the rest are platycoelous (flat on both sides).
Each caudal centra only articulated with one haemal arch at its back end, as opposed to one at each end in Dolichorhynchops.

Like other members of the Sauropterygia, the cervical vertebrae in the front half of the neck bore two pits on their bottom surfaces, separated by a median ridge; this ridge is abruptly replaced by a depression in the twelfth to eighteenth vertebrae, following which the ridge is present again.
The same pits are present on the thoracic vertebrae, where they are separated by not one but two distinct ridges.
An additional pit is present immediately beside each of the blunt keels that border the sides of the bottom face.
The neural spines of the cervical vertebrae become taller and more inclined, with the seventeenth neural spine being as tall as the centrum and being inclined at an angle of 15°.
Out of the thoracic ribs, the ninth is the longest, with rib size gradually decreasing on either side.
All of the thoracic ribs bear only one articular facet; the third rib unusually has a facet that is strongly triangular in cross-section, which is probably an artifact of preservation.

A particularly unusual feature of Mauriciosaurus is its gastralia.
There are six gastralia, each made up of a central V-shaped medial ossicle and various lateral ossicles attached to its sides.
The second and third gastralia share a single medial ossicle, as do the fifth and sixth.
The fourth medial ossicle is unusually massive, being about twice the thickness of the other medial ossicles.
All of the gastralia converge to a single central point, which is a feature that is unprecedented among polycotylids, being only otherwise seen in Cryptoclidus.
It is unlikely that this unusual arrangement is the product of taphonomic processes, since all of the gastralia seem to be preserved in alignment; the arrangement of the gastralia does not appear to be influenced by age either.
Mauriciosaurus bore 21 cervical vertebrae, at least 23 thoracic vertebrae, and at least 25 in the sacrum and tail (the delineation between these two types is not clear, since it is obscured by the ischium). The centra of Mauriciosaurus are constricted on their outer surfaces, unlike the cylindrical centra of Trinacromerum. Both the cervical and thoracic centra have length-width ratios of about 2:3; the cervical centra are procoelous (concave in front and convex behind), whereas the thoracic centra are platycoelous (both surfaces are flat). The sacral and caudal centra are generally shorter, with length-width ratios of about 1:3, but they also become narrower such that the last several preserved caudal centra are twice as long as they are wide; the first caudal centrum appears to be opisthocoelous (convex in front and concave behind), while the rest are platycoelous (flat on both sides). Each caudal centra only articulated with one haemal arch at its back end, as opposed to one at each end in Dolichorhynchops.
Like other members of the Sauropterygia, the cervical vertebrae in the front half of the neck bore two pits on their bottom surfaces, separated by a median ridge; this ridge is abruptly replaced by a depression in the twelfth to eighteenth vertebrae, following which the ridge is present again. The same pits are present on the thoracic vertebrae, where they are separated by not one but two distinct ridges. An additional pit is present immediately beside each of the blunt keels that border the sides of the bottom face. The neural spines of the cervical vertebrae become taller and more inclined, with the seventeenth neural spine being as tall as the centrum and being inclined at an angle of 15°. Out of the thoracic ribs, the ninth is the longest, with rib size gradually decreasing on either side. All of the thoracic ribs bear only one articular facet; the third rib unusually has a facet that is strongly triangular in cross-section, which is probably an artifact of preservation.
A particularly unusual feature of Mauriciosaurus is its gastralia. There are six gastralia, each made up of a central V-shaped medial ossicle and various lateral ossicles attached to its sides. The second and third gastralia share a single medial ossicle, as do the fifth and sixth. The fourth medial ossicle is unusually massive, being about twice the thickness of the other medial ossicles. All of the gastralia converge to a single central point, which is a feature that is unprecedented among polycotylids, being only otherwise seen in Cryptoclidus. It is unlikely that this unusual arrangement is the product of taphonomic processes, since all of the gastralia seem to be preserved in alignment; the arrangement of the gastralia does not appear to be influenced by age either.
Mauriciosaurus