A polished fragment of a fossil nautilus, showing the geometric arrangement of its chambers and the tube that connected them all together, known as a siphuncle (Latin sÄ«phunculus, meaning â€œa little siphonâ€), seen here as a dot repeated in each section.
This nautilus comesÂ from the Morondava River Basin, near the
town of Sakaraha, in the Atsimo-Andrefana region of southwest
Madagascar (right), in the former province of TulÃ©ar. Â ItÂ dates from the Late Jurassic period, Oxfordian age (~161 to 156
million years ago).
Â© 2014, Images and Text, Christopher Lee Matthews