Taxonomy, Evolution & Fixism

Taxonomy - the classification of organisms by presumed relationships

Humans like to give everything a name, and put everything in some sort of order. We began by giving butterflies English names, but soon discovered that the same creature had been given entirely different names in other various other countries.

If that wasn't confusing enough, two butterflies, known to early entomologists as the Selvedged Heath Eye and the Golden Heath Eye, were later discovered to be the male and female of a single species. This "new" species became known as the Gatekeeper, but is now called the Small Heath. Meanwhile it's former name Gatekeeper became applied to an entirely different species which has variously been known as the Hedge Brown, Hedge Eye, or Large Heath ! It get's worse - the name Large Heath is currently applied to yet another species, previously known as the Manchester Argus, or Marsh Ringlet !

The Linnaean System

The Swedish naturalist Carl von Linné ( Carolus Linnaeus ) wanted to put an end to all the confusion, and realised that an internationally recognised name was needed for every creature and plant, and that every organism should be classified systematically according to it's relationship with other organisms.

In 1735 he began the Systema Naturae - a catalogue of the names of all known animals and plants. A few years later, in 1753, he devised the Species Plantarum - the starting point for the classification of plants. Then, in 1758 came the 10th edition of Systema Naturae, which is usually regarded as the starting point for the classification of animals by family, genus and species.

Every known taxon is designated a binomial ( two-word ) name constructed from Latin or Greek roots. An example is the Common Blue butterfly Polyommatus icarus :

 

 

Click here to learn how to pronounce Latin names.

Click here to see the former names of all British butterflies.

Scientific names should always be written in the following format. The initial letter of the genus is always capitalised. The genus, species and subspecies are often italicised, and should correctly be followed by the author's name and the year the description of the taxon was first published :

Genus, species, subspecies, author, year

Thus the Marica Blue Ringlet from Peru was originally called :

There is no subspecies given when a butterfly is first named, these being appended only if differing races are discovered at a later date.

The classification of the Euptychia butterflies is under continuing revision, and it is now generally accepted amongst taxonomists that it should be split up, and that the sub-genus Chloreuptychia should be elevated to the rank of genus. Thus the genus becomes Chloreuptychia. The species remains as marica. The subspecies at the type locality ( the place where the first example of the taxon was discovered ) also becomes marica.

Nomadic species do not normally have subspecies, as the various populations interbreed.

Most species however are sedentary by nature, and form isolated colonies that may have no contact with each other for hundreds or even thousands of years. Evolutionists argue that each colony lives in a slightly different environment, and responds by evolving into new forms. These forms are called subspecies.

If new subspecies are discovered, they are often given a name with the suffix ~ensis, meaning "from". A hypothetical new subspecies from Brazil might for example be named brasiliensis - "from Brazil".

The taxonomic hierarchy

The following table shows Chloreuptychia marica marica in relation to the rest of the Animal Kingdom :

 

As can be seen from the table above, the Linnaean System divides the Animal Kingdom into groups called phyla. The phylum Arthropoda - animals with jointed limbs and a hard exoskeleton, is divided into classes including Crustacea ( crabs, lobsters, shrimps and woodlice ), Chilopoda ( centipedes ), Diplopoda ( millipedes ), Arachnida ( spiders, mites, scorpions and harvestmen ), and Insecta ( insects ).

The class Insecta includes over 75 percent of all animal species. It is divided into 29 orders, one of which is Lepidoptera - the group to which all butterflies and moths belong.

The order Lepidoptera comprises of about 150,000* scientifically described species. These are divided into 125 families, 6 of which are colloquially known as butterflies.

Butterflies and moths

It is wrong to think of butterflies and moths as being different things. The families which we call butterflies are generally those with brightly coloured day-flying species, and which have strongly clubbed tips to their antennae.

There are however many brightly coloured day-flying moths ( Arctiidae, Zygaenidae, Uraniidae ). There are also day-flying moths which possess clubbed antennae, in the family Castniidae. Conversely, many butterflies, particularly amongst the Hesperiidae, Satyrinae and Brassolini, are very dull and inconspicuous.

It is little known that night-flying butterflies are quite common in the tropics. Examples include the Caligo Owl butterflies, various Satyrines and certain Riodinids. In temperate regions many butterfly species which are normally day-flying will also fly at night - these include the Red Admiral Vanessa atalanta and the Monarch Danaus plexippus.

The terms "butterfly" and "moth" have little or no scientific validity. This website however concentrates mainly on the families traditionally considered as butterflies - Hesperiidae, Papilionidae, Pieridae, Lycaenidae, Riodinidae and Nymphalidae.

Taxonomic revision

The classification and nomenclature of butterflies and moths is under constant revision as the relationships between various taxa become better understood. Scientists often form different opinions about which genus a particular species belongs to, or whether two or more butterflies with very similar characteristics should be classified as separate species or as subspecies.

Occasionally a taxonomist will think that he or she has identified a "new" species, which is given a particular name, but later it is discovered that the species has already been described and named by someone else. In such cases the older name takes precedent, and the newer name is regarded as an invalid ( junior ) synonym.

As illustrated in the case of Chloreuptychia marica, advances in cladistics, phylogenetics etc can lead to new revelations ( or informed guesses ) about the relationships between species. The classification of butterflies is therefore subject to constant but necessary revision. Many species have undergone several name changes, and some such as Bia actorion, previously known as Napho actoriaena, have even been moved from one family to another :

Unfortunately the authors of butterfly books rarely manage to keep pace with these advances, so the same butterfly can be described under completely different names in different books.

Eliminating the synonyms can be a nightmare for anyone who fails to keep up to date with the latest revisions, but fortunately there are few resources exist that enable synonyms to be identified, and current names to be ascertained :

 

Newly discovered species

How do scientists describe and name a new species ?

When someone thinks they have discovered a "new" species, they have to send a sample specimen to a taxonomist for analysis. By examining the structure of the wings, legs, eyes and other anatomical features the family and subfamily can be easily determined.

Examination of the wing vein layout ( venation ) and other features then make it possible to ascertain whether the butterfly belongs to an existing genus, or whether it has unique features which require a new genus to be created for it. By dissecting and comparing the genitalia of the sample with that of other species it can then be established whether the butterfly is merely an unusual variety of a known species, or an "undescribed" species, i.e. previously unknown to science.

If it does turn out to be a new species, the taxonomist then invents a Latinised name for it, and publishes the description and name in a recognised scientific journal.

The origin of scientific names varies enormously. Some species are named after Greek gods, some are named after the place where the butterfly was discovered, or named in honour of some eminent entomologist. Names can also be descriptive of the colour, pattern or wing shape.

The Charismatic Metalmarks

Taxonomists are not usually renowned for having a great sense of humour, but amongst their more hilarious moments they have colluded to provide us with some entertaining scientific names. Hence we have a pair of metalmarks from Colombia, named by Hall and Harvey in 2002 as Charis ma and Charis matic ! Both have now been renamed rather less attractively as Detritivora ma and Detritivora matic. The new genus name refers to the fact that the caterpillars feed on decaying leaves and other detritus on the forest floor.

The World's Most Dismal Butterfly ?

Sometimes it can be difficult to think up names for some of the more mundane looking species, particularly for the hundreds of near-identical dull brown skipper species found in the neotropics. In 1997 Austin was apparently so totally unimpressed with his latest discovery that he gave a new Mexican species the unfortunate name Inglorius mediocris, which needs little translation !

Below is an example of a scientific description :

Inglorius Austin, new genus Type species: Inglorius mediocris Austin, new species Description. Palpi slender, third segment straight, protruding well beyond second segment, about equal to length of dorsal edge of second segment; antennae long, extending beyond end of forewing discal cell, nearly 60% length of forewing costa, black with pale ochreous beneath distad and below club; club just over 1/4 (28%) antennal length, bent to apiculus at thickest part, apiculus length about 2x club width, nudum grey, of 12 segments (3 on club, 9 on apiculus); forewing discal cell slightly produced, 75% length of anal margin, origin of vein CuA2 nearer to CuA, than to wing base, hindwing discal cell just over 1/2 wing width; mid tibiae with four fine spines on inner surface and single pair of spurs, hind tibiae with two pairs of spurs; forewing produced with slight concavity between CuA! and 2A; hindwing convex anteriorly, somewhat concave between CuAj and 2A; no apparent secondary sexual characters. Male genitalia with short tegumen; uncus longer than tegumen, undivided, and hood-like over gnathos; gnathos as long as uncus, divided, extending laterad of uncus in dorsal view and as rectangular flaps mesad in ventral view; vinculum sinuate; saccus short; valva very long, ampulla/costa long and sloping somewhat downward caudad, harpe long, roughly triangular ending in an inward turned point caudad, dorsal margin undulate, weakly serrate cephalad; aedeagus tubular (anterior portion missing), caudal end expanded terminally in lateral view, no apparent cornutus.

 

More "creative" species names

The taxonomist Burns was clearly having a mental block when it came to naming his new skipper - Cephise nuspesez ( pronounced "new species" ) !

Just to prove that weird humour is not confined to butterfly taxonomists ( ! ), here are some of the equally odd scientific names given to other creatures :

The above show both creativity and humour, but in 1969 when Spencer had the task of inventing names for new flies, it just came down to numbers, hence : Ophiomyia prima, O. secunda, O. tertia, O. quarta, O. quinta, O. sexta, O. septima, O. octava, O. nona, O. undecima, O. duodecima ( Latin for "first", "second", "third", etc. )

They don't always get away with it though. Common sense prevailed when Dybowski proposed the name Gammaracanthuskytodermogammarus loricatobaicalensis for a new Amphipod in 1927. It would have been the world's longest scientific name, but was rejected by the International Commission for Zoological Nomenclature on the grounds that it was unpronounceable !

 

The honour of having the longest scientific name approved by the ICZN actually goes to a species of Stratiomyid fly - Parastratiosphecomyia stratiosphecomyioides, while the shortest appears to be that of a Vespertilionid bat - Ia io, although there is a thrip with a single-letter species name - Plesiothrips o !

Click here for a further selection of strangely named butterflies.

For more fascinating scientific names, visit : Earthlink Taxonomic Puns

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