What specific part of the shell projects backward to form the noticeable spines?
Answer
Posterior marginal scutes
The spines that give the species its name are formed by the projection backward of the posterior marginal scutes, which make up the rear rim of the shell.

#Videos
The Largest Spiny Turtle on Record - YouTube
Related Questions
What is the maximum carapace length typically reported for the Spiny Hill Turtle?What is the general adult shell length range reported for this species in imperial measurements?Which sex of the Spiny Hill Turtle generally grows larger and heavier?What is the typical maximum carapace length cap for male Spiny Hill Turtles?What carapace length do female Spiny Hill Turtles frequently reach or slightly exceed?What specific part of the shell projects backward to form the noticeable spines?Where are Spiny Hill Turtles primarily found inhabiting?According to the IUCN Red List, what is the conservation status of the Spiny Hill Turtle?What colors typically make up the shell and plastron of the Spiny Hill Turtle for camouflage?How does the turtle's relatively small maximum size impact population resilience?