Borsonia mitromorphoides facts for kids

Quick facts for kids Borsonia mitromorphoides
Original image of a shell of Borsonia mitromorphoides
Scientific classification

Borsonia mitromorphoides was a type of sea snail that lived long ago. It's an extinct mollusk, which means it's no longer alive today. This sea snail belonged to a group called gastropods and was part of the family Borsoniidae.

What did Borsonia mitromorphoides look like?

The shell of Borsonia mitromorphoides was about 18 mm tall and 8 mm wide. That's about the size of a small button.

Its shell was shaped like a spindle, wider in the middle and tapering at both ends. It had a smooth, wide 'shoulder' area. The shell also had faint ridges, called axial ribs. These ribs were not very noticeable.

Inside, near the opening, there were two clear folds on a part called the columella. The opening of the shell, called the aperture, led to a narrow tube called the siphonal canal. This tube was almost as tall as the main opening.

Shell details

The shell had a broad shoulder with curved lines, showing how it grew over time. Below this shoulder, there were short, slightly raised ridges. These ridges were called axial costae. There were about 10 of them on each whorl (a full turn of the shell).

On the main part of the shell, called the body whorl, these ridges slanted sideways and disappeared towards the bottom. The top part of the shell, known as the spire, had five thin spiral lines. The entire body whorl also had spiral lines.

The spire was cone-shaped. The shell had six whorls, not counting the very first tiny part (the protoconch), which is usually broken off in fossils. The opening of the shell was narrow and pear-shaped. It gradually narrowed into a long, open siphonal canal.

Where did Borsonia mitromorphoides live?

This extinct sea snail lived in the ocean around New Zealand. It was found in rocks from the Miocene epoch. The Miocene epoch was a period of time that lasted from about 23 to 5.3 million years ago.