Sunday 29 November 2009

British Wildlife: U

Cave bear
Ursus spelaeus Rosenmüller, 1794
Ursidae; Carnivora; Mammalia; Chordata

Cave bears roamed Europe, including Great Britain, during the mid to late Pleistocene (within the last million years), becoming extinct some 20,000 years ago. As their name suggests (as does the spelaeus in the specific name), they dwelled, or at least spent much time, in caves. Remains of this species are more often found in caves than the still extant brown bear (U. arctos). Cave bears were similar in size to the largest of the brown bears and polar bears (U. maritimus) of today, having a build intermediate between the two.

Cave bear skull
Natural History Museum
March 2008

Much can be inferred about the cave bear's diet from its skull, jaw and dentition. Although the zygomatic arches (cheek bones) are huge, inferring that large muscles were attached to them, they probably did not eat a lot of meat. Like living bears, the cave bears would have been omnivores, taking as much, if not more, plant material as they would animal.

Cave bear mandible
Natural History Museum
March 2008

The canine teeth are large, as is the case in almost all carnivorans, but that doesn't necessarily mean it is carnivorous. The insectivorous aardwolf (Proteles cristatus) and the mostly-vegan giant panda (Ailuropoda melanoleuca) have impressive canines, but rarely use them for eating; they are more likely utilised in intra-specific combat only. Note the large diastema (gap) between the canines and the first premolars; this is found mostly in herbivorous animals (such as rodents, lagomorphs and ungulates), as a gap for the tongue to manoeuvre in. The cheek teeth are broad and flat, not being very sharp, perfect for eating vegetation, and sometimes grinding bones.

A very small part of the cave bear's genome has been sequenced; some DNA has been extracted from a 40,000 year old tooth, recovering 21 genes.

Uria aalge (Pontoppidan, 1783)
Alcidae; Charadriiformes; Aves; Chordata

The guillemot, or murre (as it is known in North America), is a slender auk from the North Atlantic and North Pacific coasts. They breed in huge colonies in the UK and elsewhere, being one of the most numerous of all seabirds in Britain. Despite this, I have yet to see a single one. I need to get myself to one of these colonies at some point, the Farne Islands in the North Sea looks like a good place to start.

There are other species of guillemot: Brunnich's guillemot (U. lomvia) is the only other member of the genus Uria; and the three members of the genus Cepphus - black (C. grylle), pigeon (C. columba) and spectacled (C. carbo) guillemots. Interestingly, the two genera are not that closely related, being in two different tribes (a taxonomic rank below subfamily). The distinction is made more clear in North America, by calling only Uria guillemots "murres" and the rest of them are still guillemots.

Another claim to fame for the guillemot is the laying of pyriform (pear-shaped) eggs. The most plausible theory for this is that, because the birds lay their eggs on high cliff faces with no nest, the egg cannot fall off the cliff. A pear-shaped egg will simply roll around in a circle.

(Red) underwing
Catocala nupta Linnaeus, 1767
Noctuidae; Lepidoptera; Insecta; Arthropoda

I've only ever seen one red underwing moth in my life, and wasn't armed with a camera at the time. In summer, one must have flew into my house through an open window at dusk and couldn't get out. I saw it on a wall covered with cream-coloured wallpaper, so it wasn't very well camouflaged. I intended to usher it towards an open window, so I gently prodded it and it exposed its red hindwings. Had I have been I potential predator, I would have been put off my food by this threatening display. As it was, I was a bit perturbed and backed away. The defence works!

Next week, V: a Wealden hypsilophodontid, an amphibious rodent and a venomous snake.

Sunday 22 November 2009

British Wildlife: T

Thecodontosaurus antiquus Morris, 1843
Thecodontosauridae; Saurischia; Sauropsida; Chordata

Thecodontosaurus has often been nicknamed 'The Bristol Dinosaur'. Its remains were first found in Clifton, near the Avon Gorge, and remains one of the earliest dinosaurs yet to be found in Britain. The remains date to the Late Triassic, a time when dinosaurs were radiating from initially theropod-like forms into prosauropods and basal ornithischians. Thecodontosaurus is either a primitive prosauropod or a basal sauropodomorph. This means it could be ancestral to the first dinosaurs to have become either sauropods or prosauropods (long-necks and not-quite-so-long-necks).

Thecodontosaurus antiquus bones in matrix
Bristol City Museum
September 2009

European mole
Talpa europaea Linnaeus, 1758
Talpidae; Eulipotyphla; Mammalia; Chordata

Moles are the third type of 'insectivore' found in Britain (I covered hedgehogs here and shrews here). They are distinctive-looking enough to most people for them to be familiar, despite hardly ever being seen. This probably has something to do with the excellent Wind in the Willows by Kenneth Grahame (also see the next 'T' animal). Moles spend all of their time underground; they are only seen when creating molehills or if they have been killed.

Dead European mole
Photo of specimen studied at Anglia Ruskin University, Cambridge

Moles are actually surprisingly small... before seeing one (never seen a live one, only dead ones like this) I thought they were at least hedgehog-sized, but they are really just a large shrew. The first thing one usually notices about a mole is either its claws or lack of eyes. They don't really lack eyes, but they are extremely reduced in size and are hidden under fur, and sometimes skin. The claws are incredible, especially those of the front paw, which are obviously used for digging.

Eurasian mole skeleton
Booth Museum of Natural History, Brighton
July 2008

Moles mainly eat earthworms, but will also eat other invertebrates and even other vertebrates.

(Common) toad
Bufo bufo Linnaeus, 1758
Bufonidae; Anura; Amphibia; Chordata

The common toad is, surprisingly enough, one of the most abundant amphibians in the UK, along with the common frog (Rana temporaria). Britain's other toad, the natterjack (Epidalea calamita) is much rarer and extremely localised in distribution. Common toads are found very often in bodies of water of varying size, and even found away from water outside the breeding season.

Female common toad
Epping Forest
March 2009

Females are larger than males, and during the breeding season, one can often find pairs in amplexus; this is when the male grips onto the female using 'nuptial pads' (the main method, apart from size, to distinguish the sexes) on his hands. They remain bonded until after the male has fertilised her eggs, which are laid as toadspawn in water. The spawn consists of a double row of black dots encased in a jelly strand.

Immature common toad
Enfield, North London
July 2008

Common toads metamorphose from tadpoles into miniature toads in a few months, and are often found in damp areas. I briefly kept a toadlet last year, which I named Toad of Toad Hall, feeding it on aphids and ants. It didn't really eat the ants, they would just crawl all over it. Aphids, however, it loved. I kept it for a few weeks and released it back into my garden.

Next week, U: an extinct troglodyte bear, a cryptic yet colourful moth, and an auk that lays pear-shaped eggs.

Saturday 14 November 2009

British Wildlife: S

Scelidosaurus harrisonii Owen, 1861
Scelidosauridae; Ornithischia; Sauropsida; Chordata

The Thyreophora are a group of armoured dinosaurs, most familiar as stegosaurs and ankylosaurs. The thyreophorans split into these two groups fairly early in their evolution, splitting from the basal ornithischians (bird-hipped dinosaurs: the group also including ceratopsians, pachycephalosaurs and ornithopods - horn-heads, bone-heads and duck-bills to those with a fear of Ancient Greek). Some thyreophorans, like Scutellosaurus, came about before the primal split between stegosaurs and ankylosaurs. It has been debated whether Scelidosaurus belongs in Ankylosauria or just outside it. Scelidosauridae, the family which also includes a couple of close relatives from China and Portugal, has variously been placed as a basal ankylosaur or a basal thyreophoran.

Scelidosaurus harrisonii skeletal cast
Charmouth Heritage Coast Centre, Dorset
August 2009

Despite this unsureness of Scelidosaurus' relations, there have been some wonderfully preserved specimens. One of the most recent is the one pictured above. The original, at Bristol City Museum (I didn't get a good photo of it when I was there) has been cast, and it is this cast which bedecks much of the wall at the Charmouth Heritage Coast Centre, very near to where it was found. The skull, postcranial skeleton and armour plates and scutes are all preserved. Scelidosaurus is not unique to the UK (also being found in Arizona), but the more famous finds are from here. It was Sir Richard Owen who first described Scelidosaurus harrisonii in 1861, and is thus one of the first thyreophorans to be described.

Red squirrel
Sciurus vulgaris Linnaeus, 1758
Sciuridae; Rodentia; Mammalia; Chordata

The red squirrel was, at one time, the only squirrel to be found in the UK. As such, it was a common creature. It has now been replaced, almost nationwide, by the grey squirrel (Sciurus carolinensis), introduced from North America. The grey squirrel is now one of the commonest mammals in the UK, with the red squirrel being one of the rarest. The red squirrel's strongholds in the UK are few and far between, but Scotland is where the majority of Britain's reds live.

Red squirrel
Wild in Invernessshire
June 2005

It was in that part of the UK that I saw my first, and so far only, wild red squirrel. It was feeding from a stand put up in Highland Wildlife Park, designed to attract these pretty beasts to be viewed by the public. Red squirrels also hang on in parts of Norfolk, Merseyside and the Isle of Wight, but this is due to heavy management on the behalf of wildlife biologists and conservation workers to keep grey squirrels out.

Mustela erminea Linnaeus, 1758
Mustelidae; Carnivora; Mammalia; Chordata

The stoat, as it is known in the UK, is the larger of the two classic 'weasels' to be found in Britain. Also known as the ermine (in North America, and when in its white winter coat) and short-tailed weasel (in North America only, to distinguish it from the long-tailed weasel - M. frenata), the stoat is a voracious predator, especially on mice, voles and rabbits. The European rabbit (Oryctolagus cuniculus) is larger than a stoat, and considerably heavier, but the stoat often preys on rabbits, being able to enter their warrens with ease, and hauling their prey out with surprising strength for their size and build.

A pair of stuffed stoats, with the one on the right in its winter coat (ermine)
Cambridge Zoology Museum
June 2008

In the UK, we only have to distinguish between the stoat and the weasel (Mustela nivalis). Such features you can use include size (the stoat is larger), length of tail (stoat's is longer), presence of black hair at the tip of the tail (only on the stoat), and the border between the brown and white portions of the pelt (the stoat's is clear-cut, the weasel's is jagged). Also, in the UK, only the stoat will ever turn white in winter. Unless an extremely rare albino/leucistic weasel turns up, the only white 'weasel' you'll ever find in winter in Britain is the stoat. That doesn't mean, however, that any brown 'weasel' in winter will be M. nivalis. Stoats only turn white if the temperatures drop low enough for long enough (only in the mountains here in the UK). In the rest of Eurasia and North America, however, the weasel breaks the rules and turns white in winter too. Irish stoats (M. erminea hibernica) apparently never turn white.

Next week, T: a verrucose bufonid, a myopic eulipotyphlan and a Bristolian prosauropod.

Sunday 8 November 2009

It's a shrew opossum!

Another virtual point goes to J. Velez-Juarbe for guessing that the skull belongs to a caenolestid.

Dusky shrew opossum
Caenolestes fuliginosus Tomes, 1863
Caenolestidae; Paucituberculata; Mammalia; Chordata
Cambridge Zoology Museum
June 2008

The caenolestids, shrew opossums, rat opossums, or flap-lips (!) are a family of three extant genera (Caenolestes, Lestoros and Rhyncholestes) in their own order of marsupials, the Paucituberculata. Shrew opossums, as I prefer to call them, are restricted to South America, much like the related opossums of Didelphimorphia, but even more so, not being found outside the Andes Mountains and southern 'boreal' forests of Chile, Argentina and the rest of western South America. As a result, they are poorly known, but exhibit a few distinctive features visible on the skull.

Marsupials can either be polyprotodont or diprotodont. The terms relate to the number of incisors in the upper jaw. The majority of Australian marsupials are diprotodont, having two large incisors at the front of the upper jaw, and two in the lower as well. Opossums and other related orders are all polyprotodon, with as many as five incisors on each side of the upper jaw. The Paucituberculata is one of these orders. All other polyprotodont families also have many incisors in the lower jaw, but the shrew opossums only have two, and these are extremely procumbent (forward-pointing), reminiscent of diprotodonts like kangaroos. There's also the inflected angular process (indented part of the lower jaw) present in all extant marsupials.

Dusky shrew opossum (stuffed)
Oxford Museum of Natural History
July 2008

The caenolestids are rather shrew-like in appearance, as can be seen in the above specimen. They are thought to occupy a similar niche, and since only a couple of shrew species of the genus Blarina have made it to South America, they have remained 'successful' (despite a reduction in the number of genera).

British Wildlife: R

Rhamphorhynchus jessoni (Lydekker, 1890)
Rhamphorhynchidae; Pterosauria; Sauropsida; Chordata

The rhamphorhynchoids were a group of pterosaurs, basal to the short-tailed pterodactyloids. It used to be thought that they formed a true grouping, but it seems that only the pterodactyloids form a true group within the Pterosauria, with the rhamphorhynchoids representing everything that doesn't make it into that group.

Well-preserved Rhamphorhynchus fossils are known from Germany, but some less well-preserved ones hail from England. Rhamphorhynchus had a long pointed snout (the name means 'beak snout') with a few sharp, pointed teeth that overlap each other when the snout is closed. It was very likely a fish-eater, flapping and gliding over the sea surface catching the odd fish by submerging its head. The long tail, ending in a diamond-shaped vane, is one of the most obvious features.

Cast of wing of Rhamphorhynchus muensteri (Goldfuss, 1831)
Oxford Museum of Natural History
July 2008

The wing membrane of Rhamphorhynchus has often been preserved, as you can see in this photo of a cast of the type species of the genus. I have reconstructed the animal with 'fur' because some members of the family, most notably Sordes pilosus, have been found well-preserved with a hairy integument. The purple is just whimsy.

Water rail
Rallus aquaticus Linnaeus, 1758
Rallidae; Gruiformes; Aves; Chordata

The coot (Fulica atra) and the moorhen (Gallinula chloropus) are ubiquitous in Britain near any body of water. Water rails, however, although widespread across Eurasia, and indeed in the UK, are rarely seen. I've never seen one, despite a lot of searching of reed beds at nature reserves. You'd expect a bird with a long bright red bill and zebra stripes down its flanks to be quite conspicuous, but that's not so. Like other rails and crakes, the water rail has long toes to enable it to walk on floating vegetation.

Erithacus rubecula (Linnaeus, 1758)
Muscicapidae; Passeriformes; Aves; Chordata

The robin is Britain's national bird. It's a symbol of Christmas and one of the most familiar of all small birds to the British public. Its influence on worldwide avifauna has been significant: small birds with red on their breast are found in five continents other than Europe, despite not being related to robins. Europeans named such birds 'robins' due to their resemblance to 'little robin redbreast' of the old country. The American robin (Turdus migratorius), for example, is a thrush, and the Australian robins of the genus Petroica are not related to either family.

Broxbourne, Hertfordshire
September 2009

Robins sing throughout the year, one of the only birds that does, and can always be heard on walks in the country, even in winter. They are regular visitors to bird feeders and bird tables in gardens, and most gardens have a resident pair, or are at least visited by them in their search for food. They are extremely territorial, singing to proclaim their patch as their own, and are very bold for their size, fending off predators many times bigger than themselves, such as cats, by singing at them. This extremely high pitched call seems to be coming from somewhere else, and this ventriloquism works, as the cats seem confused by it all!

Next week, S: a primitive thyreophoran, a tufted-eared rodent and a sinuous mustelid.

Friday 6 November 2009

Ganges River Dolphin! And guess the skull III

You've done it again! Indeed, the skull from the previous post has been correctly identified by J. Velez-Juarbe:

Ganges river dolphin
Platanista gangetica (Lebeck, 1801)
Platanistidae; Cetartiodactyla; Mammalia; Chordata
Cambridge Zoology Museum
June 2008

It's those overgrown squamosals (part of the jaw) that give it away as one of the two members of the Platanistidae. The Ganges river dolphin is one of three truly freshwater dolphins currently extant. The franciscana (Pontoporia blainvillei) of South America, although classed as a river dolphin, is mostly estuarine, and the baiji, or Yangtze river dolphin (Lipotes vexillifer) is now considered extinct. Some wonderful photos of the Amazon river dolphin, or boto (Inia geoffrensis) have been highly commended in this year's Wildlife Photographer of the Year competition, including a pair of botos playing with a fruit.

The next one I think is difficult, but there are enough clues visible to get it if you know your mammalian orders!

Thursday 5 November 2009

It's a tenrec! And guess the skull II

The answer, as J. Velez-Juarbe correctly guessed, to the question I posed in the previous post is the tailless tenrec, Tenrec ecaudatus.

Tailless tenrec
Tenrec ecaudatus
Tenrecidae; Afrosoricida; Mammalia; Chordata
Cambridge Zoology Museum
June 2008

Tenrecs are hedgehog-like mammals exclusive to Madagascar and some nearby islands. Their closest relatives, apart from the African otter shrews, are the also African golden moles of the Chrysochloridae. They were all formerly considered members of the Insectivora (also called Lipotyphla), but are now placed within the Afrotheria group, containing such odd bedfellows as elephants, sengis (formerly elephant shrews), sirenians (manatees and dugongs), hyraxes and aardvarks. All orders of Afrotheria supposedly originated in Africa, where the majority of the members still live.

So what's this then?

Tuesday 3 November 2009

Guess the skull...

I've been feeling quite crappy of late, I think I've got a cold. Anyway, I've been working heavily on my book for the last couple of weeks, hence a lack of posts apart from the Sundayly A-Z ones. When I feel up to it, I'll reveal some of the more interesting names I've researched.

Until then, however, I'll leave you with a skull. Guess the mammal whose skull appears below for a virtual point.

Sunday 1 November 2009

British Wildlife: Q

Quinquecosta williamsi Tripp, 1965
Pliomeridae; Phacopida; Trilobita; Arthropoda

Quinquecosta is a trilobite of the family Pliomeridae, belonging to the order Phacopida. The phacopidans were capable of rolling into a ball, most likely for defence, and many fossils of this type of trilobite are found in such a shape. They had large eyes with visible lenses, the schizochroal eye, yet members of the Pliomeridae had the more typical holochroal eye, with much smaller lenses which are not separate from each other.

Purple hairstreak
Quercusia quercus (Linnaeus, 1758)
Lycaenidae; Lepidoptera; Insecta; Arthropoda

This is a female purple hairstreak: although she is wonderfully purple, the male is even more so. I wasn't aware of this when I was drawing Q for this alphabet! Quercus is Latin for 'oak', and the name reflects this insect's lifecycle. The female lays her eggs on oak buds, and the larva lives inside the buds. The adults then spend much of their time in the canopy of mature oak trees. The genus is also known as Neozephyrus, but that doesn't begin with 'Q', does it?

Coturnix coturnix (Linnaeus, 1758)
Phasianidae; Galliformes; Aves; Chordata

The common quail is Britain's only native migratory game bird. It only spends the summer months in the UK, but is often kept as a farm bird for its flesh, but more frequently for its eggs, which are considered a delicacy.

Adult common quail
Geçitköy, North Cyprus
April 2009

Quails are hard birds to spot in the wild. They are naturally shy and very cryptically-coloured, but can betray their presence with their distinctive call, often transcribed as 'wet my lips, wet my lips!' I don't see the similarity myself.

Common quail chick
Geçitköy, North Cyprus
April 2009

Quails of the genus Coturnix are commonly kept as ornamental and farmyard birds, with Asian members of the genus (Chinese, or blue-breasted quail, C. chinensis, and Japanese quail, C. japonica) the most popular. In Europe, however, it is predominantly the common quail which is kept.

Next week, R: a long-tailed purple pterosaur, a cryptic gruiform and Britain's national bird.