Taxonomy Trail - Closed

The balcony levels of the Natural History Museum have been closed following a safety review. There are too few emergency exits from upper levels. The National Museum of Ireland has developed a plan to address this but funding for that plan is not yet available.

What you are missing:

Taxidermy (from the Greek for ‘arrangement of skin’) is the obvious task of a natural history museum. The main work of most curators, however, is taxonomy (from the Greek for ‘arrangement of names’). The science of taxonomy is the naming of animals and their arrangement into groups. It is our way of making sense of the incredible diversity of the natural world.

Nephrops norvegicus, also known as Norwegian lobster, Dublin Bay prawn or langoustine

So what is in a name? Many animals are familiar to all of us and have common names in our own language. This works well until you travel to countries with other languages or until a scientist encounters several animals within a group with only one common name. The international standard in science is to use names with two parts based on Latin or Greek words. One person’s Norwegian lobster is another’s Dublin Bay prawn or even langoustine. In this way the scientific name Nephrops norvegicus avoids the confusion of the fishmonger’s counter or the restaurant menu and serves as the name for this animal in all scientific works in all languages. The first part of the name indicates the genus, or group of animals that are close relatives, just like a surname. The second part of a scientific name indicates the particular species, or grouping of identical animals.

Lobsters and prawns are similar in appearance and are close relatives. They are arthropods, a term used to describe animals with jointed legs, including crabs, spiders and insects. Arthropods form the largest grouping of animal species and show incredible diversity. A small part of this diversity can be seen on part of the top balcony level in the Museum.

Arthropods come in a wide variety of shapes and sizes. Crabs such as Cancer pagurus show some of the features seen in all members of this group. Legs are in pairs along either side of the body and are specialised for different functions. Crabs are decapods (‘10 legs’), with four pairs of legs for walking and a pair of specialised legs with pincers at the front. Some walking legs may be adapted for swimming, as in the paddle-shaped legs of Zosimus aeneus of the Indo-Pacific region. Like all arthropods, crabs wear their skeletons on the outside. This is good for protection but means that in order to grow they must shed their outer layer from time to time and grow a new one.

Tarantula Acanthoscurria geniculata from Brazil with hummingbird

Spiders are also arthropods and share the jointed legs of crabs as a feature of the group. One main difference is inside their bodies – unlike crabs, they have lungs and breathe air. Spiders evolved more than 500 million years ago and became some of the first animals to leave the sea and conquer the land. They are found in a wide range of habitats and are complex and fascinating creatures. Tarantulas such as Acanthoscurria geniculata are predators of the rainforest floor in Brazil.

The most diverse group within the arthropods is that of the insects. With a wingspan of 18cm, the grasshopper Tropidacris dux from South America is one of the largest examples in its group. Like other grasshoppers, they can communicate by means of sound. This is done by rubbing the strong, muscular hind legs against the outer cases of the wings when the latter are closed and folded along the animal’s back. Grasshoppers can recognise other specimens of their own species by these sounds, which are also used by entomologists to identify species that may appear very similar at first glance.

Insects show amazing variety in the ways in which their versatile body materials have evolved to different ways of life. Camouflage is a feature highly developed in some larger insects, some of which have evolved body shapes that mimic their surroundings. The leaf-like insects include Phyllium cruorifolium, which is hard to distinguish from a leafy background in its native Sri Lanka.

Harlequin beetle Acrocinus longimanus from Peru

Beetles form the largest group of insects. There are hundreds of thousands of species worldwide. Many are highly specialised, concentrating on a particular food source or way of life. The harlequin beetle Acrocinus longimanus from South America has the longest legs of any beetle. Spectacular insects such as this can be under threat from collectors. Museums have played their role in capturing endangered species in previous centuries; now it is the souvenir hunter who threatens such animals in the wild. You can buy a harlequin beetle over the Internet – but please don’t!

 
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