Saturday 15 August 2009

British Wildlife: F

Flexicalymene caractaci (Salter, 1865)
Calymenidae; Phacopida; Trilobita; Arthropoda

My favourite of all invertebrates, with the possible exception of the oribatid mites, are the trilobites. They came in a variety of forms, from the tiny, blind agnostids to ornately spined members of the Phacopidae (not to mention flying ones). They lived in marine environments throughout the Palaeozoic Era, being on Earth for a period of almost 300 million years.

The suborder Phacopina are known for their amazing eyes (Phacops means 'lens face'). In a good specimen, you can see, and even count, the individual lenses of each eye. This is because they are much larger than usual. This type of optic structure is known as schizochroism. The suborder Calymenina, to which Flexicalymene belongs, has a different eye structure, called holochroism. The lenses are smaller and much harder to count.

Flexicalymene ouzregui from Morocco, but bought from a museum gift shop

Flexicalymene is known from many parts of the world, and although being found in Britain, fossils are rare. Most of those for sale come from Morocco, which often yields beautiful trilobites. Flexicalymene lived during the Ordovician period (about 450 million years ago), a time when all animal life on Earth was marine, and the only lifeforms to colonise the land were primitive plants. Animals that may have predated trilobites in the Ordovician include the earliest sharks and nautiloids (both groups still being found on Earth today).

Scottish wildcat
Felis silvestris grampia Miller, 1907
Felidae; Carnivora; Mammalia; Chordata

Britain currently has only one native felid, the Scottish wildcat. Lynxes (Lynx lynx) were found here until they were hunted to extinction by humans, and some other exotic species, like the leopard (Panthera pardus), jungle cat (Felis chaus) and leopard cat (Prionailurus bengalensis) have been sighted in remote, and not-so-remote, parts of the UK, obviously released by humans from captivity. But only the Scottish wildcat remains.

It clings on, just about, in conifer forests in northern Scotland. One of the main threats to its survival is hybridisation. There are many subtle differences between a true wildcat and the domestic cat, including size, cranial characteristics and teeth, but ultimately, both belong to the same species, so when two cats meet at the right place at the right time (and are of the right sex), they will ultimately try to reproduce, whether they are both wildcats, both domestic, or one of each. This dilutes the gene pool, and there are very few places in Scotland where domestic cats haven't reached.

Scottish wildcat in captivity
Highland Wildlife Park, Invernessshire, Scotland
June 2005

Their status as a unique subspecies is in doubt; they have very few differences with wildcats from continental Europe, known as Felis silvestris silvestris. They are obviously different from the African wildcats, generally known as F. s. lybica and those from western Asia, known as F. s. ornata. Because they may not be an exclusive to Britain, it may be possible to introduce wildcats from the Continent, where they are more plentiful and widespread, to boost the gene pool of the Scottish wildcats. The fact remains, however, that all populations of wildcats will interbreed with domestic cats, because wherever there are humans, their pets usually follow.

(Red) Fox
Vulpes vulpes Linnaeus, 1758
Canidae; Carnivora; Mammalia; Chordata

Most people in the UK have seen a fox. Many of those, if not most of them, have seen them a city or town. They seem to have replaced the hedgehog as the most common and ubiquitous urban mammal. I'm not complaining; a wild animal is a wild animal and I love seeing foxes when out at night.

Red fox cub in my back garden
August 2007

But as you can see, it doesn't even have to be dark to see them. When foxes have cubs, they are constantly active and on the search for food. The cubs, more curious than wary of humans now that hunting is (mostly) banned, are easy to watch, and I got within 3 metres of this youngster as it watched me snapping photos of it. Occasionally we get a glimpse of one of the adults; the dog fox (male) is a huge and impressive-looking animal in his full coat. Unfortunately, it is all too common to see foxes with manky-looking coats and thin, rat-like tails, probably from infection from scabies mites (Sarcoptes scabiei canis), causing mange. This year, the local foxes have been playing havoc in our garden, the cubs being extremely playful and uprooting plants, including my mum's prize dahlias! There's not an awful lot we can do about it, and anyway, the cubs will soon grow up and disperse.

Next week, G: a Mesozoic crocodylomorph, a brightly coloured corvid, and an endemic game bird.

1 comment:

Zachary Miller said...

Have you noticed that at least three wild cats (British and African wildcats and the African fishing cat) have tabby colors? I wonder if that means tabbies are the closest to the "ancestral" stock?