大象传媒

Millipedes are herbivores and were amongst the first land animals to colonise the early mini-jungles of mosses and liverworts.

Millipedes certainly hold the record for most legs, but they are also the oldest known land creature, with one particular species living 428 million years ago.

Modern millipedes grow to only a few inches long, but one prehistoric type was as long as a cow.

Their ancestors were marine creatures related very distantly to crustaceans such as shrimps. It is from these common ancestors that they inherited their segmented bodies as well as their external skeletons.

But whereas their water-living ancestors used feathery gills alongside each leg to extract dissolved oxygen from water, the first millipedes developed a system of branching tubes within each segment.

These tubes open to the outside through a tiny pore on the side of each segment and allow air to diffuse to all parts of the body so that the tissues can absorb oxygen directly. But the millipedes didn't have the land to themselves for long. Hunters soon came up from the sea to prey on them.

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