What on Earth Is the T. Rex Leech?

February 21, 2019
Tyrannobdella rex (T. rex leech) has very distinctive characteristics in regards to the rest of its family members --their teeth are five times larger than those of other leeches.

A little over 10 years ago, experts discovered a new species of leech in Peru: the T. rex leech. The animal, which appeared in the nose of a small girl of nine years of age, received the scientific name of Tyrannobdella rex.

The finding was surprising, because the leech, measuring almost 2 inches, had a single jaw with huge teeth. And it was different from all other species of its kind.

Scientists had found something similar years earlier in the noses of other children from the same country. However, researchers hadn’t paid much attention to that fact. But then, after some investigations, they discovered that both the girl and the other little ones had all bathed in the same waters of the Amazon.

Since then, they’ve found other specimens in remote areas of the Amazon rain forest. This interesting toothed leech has now attracted the attention of many scientists. We’re going to be finding out all about it!

Unfortunately, this species has become quite infamous and there’s often disgust at the very mention of its name. Is the bad reputation of this leech justified?

Why is it called T. rex leech?

The T. rex leech is the king of all leeches, as its name literally means ‘the tyrant leech king’. The species from which it evolved most likely coexisted with dinosaurs. It is claimed that they also shared the same environment over 200 million years ago.

The T. rex leech and its teeth.

There are four more species that share the same abbreviated form T. rex: two fossils from the Miocene period (a beetle and a snail), an ant that lives in Malaysia, and, of course, the famous dinosaur from the Cretaceous period.

Characteristics of T. rex leech

This leech is smaller than a pinky. However, its jaw and teeth are five times larger than those of every other leech.

T. rex belongs to a group of leeches from the Praobdellidae family. In addition to the Amazon rain forest, the members of this family mainly live in Africa, the Middle East, and Mexico.

This leech is not exactly popular, and considered pretty disgusting, but, in fact, these leeches have lived here long before humans made an appearance.

It’s likely that, from the perspective of balance in the animal kingdom, the T. rex leech has an important mission to accomplish.

What does the T. rex leech feed on?

Although researchers haven’t yet agreed on what the main source of food for the T. rex leech is, many claims are out there. Like many other species of leeches, T. rex is a bloodsucker. And so, its favorite food is the blood of other animals.

The preferred sources of protein for the T. rex seem to be aquatic mammals. The leeches latch onto the nose and mouth of these mammals and remain there for weeks while they suck their blood. After that period they go in search of another victim to stay on. Don’t worry, they don’t empty the victim’s blood supply!

A Tyrannobdella rex on a petri dish.
The feeding behavior of the T. Rex leech, like that of the entire Praobdellidae family, puts the health of human animals at risk in different regions of the planet.

Ancestors and relatives of T. rex leech

The appearance of the T. rex leech was a great challenge for scientists. They reluctantly and completely revised their phylogenetic makeup and compared it with that of other families of leeches.

Due to its morphology and DNA, T. rex leech is a cousin of another one that lives in Mexico, which lurks around in the mouth of cattle: the Hirudinaria granulosa.

It’s also a relative of Pintobdella chiapasensis, another leech that also inhabits Mexico, specifically in Chiapas. This one feeds usually on tapirs, but it also infects cattle.

Other species of leeches have close ties to the T. rex leech, like the Dinobdella ferox, which is native to India and Taiwan. This leech is well known and feared for its habit of consuming the mucous membranes of human orifices.

It’s very likely that the common ancestor of all these leeches was around before the continental divide. In the supercontinent known as Pangaea, that is. This would explain the fact that they’re spread around many distant territories.