A new species of caecilian -- an amphibian that superficially resembles an earthworm or snake -- that feeds on its mother's skin

has been found in French Guiana and described by evolutionary biologists.

These mysterious creatures have been around for about 250 million years -- since before the dinosaurs -- but since they live mostly in the ground in the hot moist tropics, they have generally been difficult to study. Although they look a bit like worms, they have large mouths and sharp teeth that adults use to eat things like worms and termites. Their eyes are covered by bone -- meaning they don't see very well -- but they have tiny tentacles on the front of their head, which detect chemicals in the soil.


The Microecaecilia dermatophaga is the first new caecilian to be described from French Guiana in more than 150 years. It is the third species where the young animals have been observed feeding on the skin of their attending mother, a practice called "maternal dermatophagy".

This skin-feeding was first observed in the Boulengerula taitanus species; the hatchlings of this caecilian feed on the lipid-rich outer layer using a special set of teeth. It was then seen in the Siphonops annulatus. However, these species of skin-feeding creatures are not very closely related and have evolved separately for more than 100 million years.

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The team -- made up of researchers from The Natural History Museum and Harvard University -- found the animals by digging in forest soil between buttress roots of trees. Specimens were killed by anaesthesia and then fully examined, with their teeth counted and their bodies measured.

At the same time, live animals were also kept in captivity in an artificial nest. Parent-offspring interactions were observed intermittently. The mothers were found to lay eggs and the hatchlings then ate the skin -- an extra layer that is rich in fats that grows when females reproduce -- of their mother. As the hatchlings grew, changes in the mother's skin tone were observed.

The hatchlings use special "foetal" teeth to graze upon the modified skin of the mother. They move rapidly across the motionless parent, ingesting pieces of skin as they go along. The researchers weighed the mother and hatchlings to discover that the mother's weight decreased as the hatchlings' weight increased.


This behaviour has only relatively recently been discovered because caecilians spend so much of their time in the soil and must be disturbed to be observed. "What we've found is another species that's a skin-feeder, but most importantly, it's another species that's quite distantly related to other skin-feeders we've found, meaning that skin-feeding is probably an ancestral characteristic for caecilians," co-author Emma Sherratt told the Natural Environment Research Council.

This recent find suggests that caecilians evolved this form of maternal care very early on in their evolution. Sherratt went onto say that the caecilians are still very poorly understood compared to most other creatures.

You can read the full study on PLoS One.