s Spineless Creatures (part 1) - Hull Museums Collections

Spineless Creatures (part 1)

Detail of Ammonite

Dinosaurs are vertebrates, just like you and me. We have a skeleton with a backbone. But what are invertebrates? Well, as the name suggests they are animals without a backbone. A great variety of invertebrate organisms evolved in the oceans over a very long period of time, and today we find them as fossils encased in rocks. In-fact invertebrate fossils are far more common than vertebrate fossils.


Ancient Marine Life



Throughout Earth's history the oceans have been a host to a vast life source. Marine invertebrates including corals, marine snails, and crustaceans (crabs and lobsters) evolved over 500 million years ago and are still living today. Other marine invertebrates became extinct and their remains preserved as fossils. Do you know what fossil crinoids, echinoids, belemnites or ammonites are or look like?


What are Ammonites?



Ammonites are an extinct group of cephalopods. They are related to the living Nautilus, and belong to the Mollusc family. Ammonites thrived in the seas throughout the Triassic, Jurassic and Cretaceous Periods (245-65 million years ago).


The ammonites have a coiled shell within which the soft parts of the animal lived, much like a snail. The shell is divided into chambers, which was used to trap air and help with the animal's buoyancy in the water, much like a submarine. They could swim up to depths of 500 metres, catching and feeding on fishes and crustaceans.


View all of the ammonites from our collections or use the search.


What are Belemnites?



Belemnite (Hibolites aff. jaculoides)Belemnites are the preserved internal shell of an extinct marine cephalopod, which were abundant during the Jurassic and Cretaceous Periods (205-65 million years ago). They are related to modern octopus and squid, and belong to the Mollusc family.


In the oceans these belemnites would have looked like a squid, with a soft body enclosing the internal shell. Similar to the squid they would have used jet propulsion to chase their prey, catch small fish with their tentacles and eat them with their beak-like jaws. However unlike the modern squid, belemnites carried a serious of small hooks, instead of suckers, of the end of their tentacles to grab their prey.


View all of the belemnites from our collections or use the search.


What are Bivalves?



Bivalves are a group of marine and freshwater invertebrates. The group includes living representatives such as mussels, cockles and oysters. They belong to the Mollusc family, a group that includes gastropods (snails) and cephalopods.


The bivalve shells consist of two hinged valves. The valves open to admit water or close to protect the soft body within. Most bivalves live on the surface of the seabed but some burrow into mud or sand. One of the most commonly found fossil bivalve is the extinct Gryphaea. It has a thick calcite shell and is typically found in Jurassic (205-145 million years ago) marine sediments.


View all of the bivalves from our collections or use the search.