Where does the prominent, long spine that secured the name Xenacanthus project backward from?
Answer
The nuchal region (back of the head)
The primary feature giving *Xenacanthus* its name—the 'strange spine'—is specifically located projecting backward from the nuchal region, which is defined as the back of the head. This posterior projection is morphologically unique among known shark groups. Coupled with a potential second spine near the tail structure, this paired spination likely served as a passive defense mechanism, acting as a deterrent against larger predators within its ancient ecosystem by relying on its physical shape rather than active evasion tactics.
Related Questions
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