Tullimonstrum

Impression of Tullimonstrum in the Museo Civico di Storia Naturale di Milano. Positive and negative side. The tail is pointing upwards, the head lying down with his trunk inside.

• Mazon Creek ( Illinois / USA)

Tullimonstrum is an extinct, invertebrate from the Upper Carboniferous, the systematic affiliation is so far a mystery. Fossils of Tullimonstrum were found in the Mazon Creek fossil site of near Morris, Illinois. It was named after its discoverer, the fossil collector Francis Tully, and is the state fossil of Illinois. Since then, have been found by professional paleontologists and amateur collectors of thousands of fossils of the genus. The only way is described Tullimonstrum gregarium.

Features

The fossils of Tullimonstrum have a body length of 15 to 43 cm, most specimens are 31-35 inches long. Tullimonstrum had a soft, bulbous body, which was broken down. At the back end was a diamond-shaped tail and at the head of a trunk at the end of a busy 14 with small, sharp teeth jaw was, which was 5.5 to 16.5 mm long and 3.5 to 6 mm wide. The teeth have a length of 0.5 to 2.4 mm. At the transition from the body to the trunk you can see a crescent-shaped structure behind it are two stalked eyes. Tullimonstrum was a floating, predatory animal who probably had a similar lifestyle as today's arrow worms.

System

The systematic affiliation of Tullimonstrum has not been clarified until today and it was assumed that it belongs to the conodonts, the cord or the annelids. The eyes, the trunk and the teeth have similarities with those of Pterotracheoidea, a superfamily of snails, which has a pelagic lifestyle. You may Tullimonstrum is therefore a mollusc.