Thursday 25 December 2008

Four Temnospondyls

“Four Temnospondyls”
Coloured pencil illustration
August 2008

Top left:
Eryops megacephalus Cope, 1877
Eryopidae; Temnospondyli; Amphibia; Chordata
Early Permian North America

Top right:
Mastodonsaurus giganteus (Jaeger, 1828)
Mastodonsauridae; Temnospondyli; Amphibia; Chordata
Mid-Triassic Germany

Bottom left:
Platyhystrix rugosus (Case, 1910)
Dissorophidae; Temnospondyli; Amphibia; Chordata
Early Permian North America

Bottom right:
Gerrothorax pulcherrimus (Fraas, 1913)
Plagiosauridae; Temnospondyli; Amphibia; Chordata
Late Triassic Germany

Paracyclotosaurus davidi Watson, 1958
Capitosauridae; Temnospondyli; Amphibia; Chordata
Triassic Australia (and other parts of Gondwana)
Natural History Museum, London
March 2008

While the folks are all watching Eastenders, I thought I’d pop upstairs and do a quick blog post. I like temnospondyls, they are a group of amphibians long extinct that left no living descendants. The group containing all living frogs, toads, newts, salamanders and caecilians is the Lissamphibia. Temnospondyls are generally differentiated from the other amphibians by their vertebrae (the name “temnospondyl” itself is Greek for “cut vertebra”), but not all temnospondyls share this feature.

Eryops megacephalus (“big-headed, drawn-out face”) was up to 2 m (6’) long (much bigger than any axolotl I’ve seen). Mastodonsaurus giganteus (“giant nipple-toothed lizard”) was slightly smaller but looked more crocodilian than Eryops. Platyhystrix rugosus (“rough flat porcupine”) looks like an amphibian analogue of Dimetrodon or Edaphosaurus, the therapsids like those that gave rise to all mammals. If the sail served a similar function, it would be the only amphibian we know of to have the ability to thermoregulate! Gerrothorax pulcherrimus (“very pretty wicker chest”... where do these names come from?!) looks like a lemon-headed axolotl. It is known for its inability to open its lower jaw, so instead, it raises its skull when it wants to eat, like a dustbin lid.

I purposefully chose bright colours for all these temnospondyls, but the colours for Gerrothorax were particularly inspired by Stewie Griffin of Family Guy... the shape of the head reminded me too much of him so I gave it red dungarees to match its gills.

Hope you’re having/had a good Xmas, I didn’t even eat that much (yet) and I’ve been feeling queasy.

Wednesday 24 December 2008

Photo of the Day #24: Rüppell's griffon vulture

Rüppell's griffon vulture
Gyps rueppelli (Brehm, 1852)
Accipitridae; Falconiformes; Aves; Chordata
London Zoo
November 2008

Whilst in the car for the entire duration of my stay in North Cyprus in October, I pointed my face skywards to look for griffon vultures (the European species, Gyps fulvus), but didn't find any. Vultures are charismatic creatures; for all their bad reputation, they certainly have beautiful plumage, but obviously not on the head. Rüppell's griffons are found in savannah habitats of the central parts of Africa, from Guinea in the west to Tanzania in the east. There are related species found in many parts of Eurasia, with the European griffon being found in western Europe towards central Asia, and other, severely endangered Gyps species from India and surrounding areas.

Sunday 21 December 2008

Basilosaurus Bounty

Basilosaurus isis (Andrews, 1904)
Basilosauridae; Cetartiodactyla; Mammalia; Chordata

Black-and-white illustration by Mo Hassan, December 2008
Photograph taken at the Natural History Museum, London, February 2008

Basilosaurus is an 18 metre (60 foot) long extinct whale from the Eocene of the USA, Egypt and Pakistan. It lived in shallow waters and was a true carnivore with large teeth. I have illustrated Basilosaurus as being coloured like an orca, as that is probably the nearest living analogue to the extinct cetacean in terms of it being a large carnivorous whale. It was first thought to be a marine reptile, hence the name “Basilosaurus”, meaning “king lizard”. It was then realised by the great anatomist and first superintendent of the NHM, Sir Richard Owen, that it was indeed a mammal.

The arrow on the skull (notice the caption says “Prozeuglodon isis”; this is a synonym of Basilosaurus isis) illustrates where the nostrils of the animal would be. They are not at the tip of the snout, like their ancestral ungulates, nor are they at the top of the head, like the derived whales and dolphins of today. The specimen is a cast of actual skull, and is placed in between Andrewsarchus (coming soon!) and Prosqualodon, showing the movement of the nostril from snout to head in early whales and their ancestors at the Natural History Museum.

All modern whales and dolphins today (with the notable exception of this bottle-nosed dolphin) have lost their hind legs; this is most likely to with streamlining of the body for ease of movement in water, a denser medium than air. Basilosaurus still had vestigial hind limbs, as can be seen from the illustration.

I will attempt to draw other marine mammals at some stage, and will soon try Paleoparadoxia tabatai, the desmostylian. That should be fun, although I only know what the skeleton looks like and haven’t seen a reconstruction of one properly before!

Thanks to Brian Beatty for helping me with a few taxonomic issues; this post is for you and any other cetacean-lovers who read this!

Saturday 20 December 2008

Happy Holidays

To all of my readers, friends and family...

Have a happy Xmas and a prosperous New Year!

The caption competition is open until the 31st, so keep the entries coming in, then I can decide on a winner in the New Year.

Saturday 13 December 2008

Caption competition

As featured on Tetrapod Zoology, here is that odd picture I took on the Isle of Wight in May. Although what was actually happening was Dave Martill demonstrating the size of the iguanodontids that made the footprints whose reverse impressions litter this part of the coast, how about a caption competition? Prize for the best caption is an A3 drawing of the tetrapod of your choice.

Sunday 7 December 2008

Teals part 2 (photo special)

Marbled teal
Marmaronetta angustirostris (Menetries, 1832)
Anatidae; Anseriformes; Aves; Chordata
London Wetland Centre
June 2006

Also called the marbled duck, this "teal" is not closely related to the others, being closer to the pochards (here and here). It is found in southern Europe and parts of western Asia.

The preceding illustration, titled Marbled Teal in Blue and Orange was created using MS Paint to "paint" over the original photo using either realistic colours (the teal) or eye-catching ones (the ripples in the water). I entered this, along with this to a Natural History Museum art competition earlier this year. Unfortunately, I couldn't go to the judging because I was convalescing after my operation; alas, I didn't win anyway.

Madagascar teal
Anas bernieri (Hartlaub, 1860)
Anatidae; Anseriformes; Aves; Chordata
London Zoo
August 2005

A small, sombre-coloured teal endemic to Madagascar. It is not as rare as the other Malagasy endemic, the Madagascar pochard (Aythya innotata) which was until recently considered extinct; it was then rediscovered on a remote lake.

Male ringed teal
Callonetta leucophrys (Vieillot, 1816)
Anatidae; Anseriformes; Aves; Chordata
London Wetland Centre
October 2008

Again, not a true teal, but a very pretty small duck from South America. Males look as pictured above, and again, females are duller.

Chestnut teals
Anas castanea (Eyton, 1838)
Anatidae; Anseriformes; Aves; Chordata
London Wetland Centre
December 2006

The Australian member of the teal clan, the chestnut teal is coloured as its name suggests, with the male also having green and white in his outfit, and females duller. Australia has some nice wildfowl, including the gorgeous black swan (Cygnus atratus) and aggressive and inquisitive magpie goose (Anseranas semipalmata). The exhibit at the London Wetland Centre for that country is a nice walkthrough with a large pool. The magpie geese hang out in a far corner usually, and I would not advise approaching them, as they do bite, one bit my shoe once!

Brown teal
Anas chlorotis Gray, 1845
Anatidae; Anseriformes; Aves; Chordata
London Wetland Centre
February 2006

New Zealand also has many endemics, including its own shoveler, shelduck and the teals. All are threatened, some more so than others, but all are brown, the males having a green sheen to the head.

I will come back to ducks at some point in the future, so stay tuned, anatophiles!

Saturday 6 December 2008

Teals part 1 (Photo special)

The word “teal” has two meanings; to some it is just a blue-green colour like a dark turquoise; to others it is a type of small duck. In Britain, that small duck is specifically the common teal (Anas crecca). In North America, there are other species, particularly the green-winged teal (A. carolinensis) that looks a lot like the common teal, the blue-winged teal (A. discors), and the cinnamon teal (A. cyanoptera). Elsewhere in the world, there are even more species of Anas that are known as teals, and even members of other duck genera. Today I will showcase 6 teals, and this will be followed by a further 5. Eleven ducks in one post will be a bit too much, even for anatophiles like myself.

Male and female common teals
Anas crecca Linnaeus, 1758
Anatidae; Anseriformes; Aves; Chordata
London Wetland Centre
January 2008

The common teal is a resident of Britain, but becomes more numerous in winter when migrants come in from cooler areas. They are my favourite of the winter ducks, especially due to their dinky size and the male’s colourful plumage, consisting of a brown and teal head, grey body and a buffy rump with a black border.

Male Baikal teal
Anas formosa Georgi, 1775
Anatidae; Anseriformes; Aves; Chordata
London Wetland Centre
October 2008

Baikal teals are an Asian species that is threatened with extinction. It looks a lot like a common teal, but has buff on the head as well as brown and teal.

Male falcated teal
Anas falcata Georgi, 1775
Anatidae; Anseriformes; Aves; Chordata
London Wetland Centre
October 2008

The falcated teal is another Asian species, but is larger than other teals, so is sometimes known as the falcated duck (there’s no real difference, just that smaller ducks are called teals). Its similarity to both the common and Baikal teals suggests it should be called a teal. “Falcated” means “sickle-shaped”, and this probably describes some of the feathers on the male’s sides quite well.

Speckled teal
Anas flavirostris Vieillot, 1816
Anatidae; Anseriformes; Aves; Chordata
London Wetland Centre
October 2008

Male and female speckled teals, with their yellow and black bills and neat brown-spotted plumage, do not differ. They are found in South America.

Puna teal
Anas puna Tschudi, 1844
Anatidae; Anseriformes; Aves; Chordata
London Wetland Centre
October 2008

The South American puna teal gets its name from the Andean region where it comes from, with an alpine cold climate, also inhabited by the puna flamingo (Phoenicoparrus jamesi) amongst other unique species. They have a distinctive bright blue bill along with black cap and white cheeks. The closely-related silver teal (Anas versicolor) lacks the blue bill but is otherwise very similar, and is even sometimes regarded as conspecific.

Laysan teal
Anas laysanensis Rothschild, 1892
Anatidae; Anseriformes; Aves; Chordata
London Wetland Centre
October 2008

You might think the Laysan teal looks a lot like a female mallard, and you’d not be wrong to think that, as it is often regarded as a subspecies of that cosmopolitan species. The Laysan teal is native to Hawaii and the nearby Laysan Island and is incredibly rare, Critically Endangered even. Drakes do not have the distinctive green head, white collar and chestnut chest of mallards; instead both males and females have a white patch around the eye.

In the next post, Madagascar, chestnut, brown, ringed and marbled teals! Stay tuned!

Wednesday 3 December 2008

Photo of the Day #23: Pochard

Aythya ferina (Linnaeus, 1758)
Anatidae; Anseriformes; Aves; Chordata
Enfield Town, North London
November 2008

Top photo: male
Bottom photo: female

The pochard, sometimes known as the common pochard to distinguish it from other similar species, is a species of diving duck from Eurasia. I look forward to winter where I live because the resident population of waterfowl in my local river is boosted by wintering tufted ducks (Aythya fuligula) and pochards. The male is very pretty with his russet red head, scarlet eye and pale grey and black body plumage; the female is a more muted version of her mate without the red eye. Relatives of the pochard found across the world include birds known as redheads, canvasbacks, hardheads, scaups and the ferruginous duck. There is another genus of pochards, Netta, but they are not very closely related to the Aythya ducks.

Tuesday 2 December 2008

Photo of the Day #22: Egyptian Goose

Egyptian goose
Alopochen aegyptiacus (Linnaeus, 1766)
Anatidae; Anseriformes; Aves; Chordata
London Wetland Centre
October 2008

One of my favourite of London's wildfowl, the Egyptian goose is not native to Britain, but was introduced from Africa as a decorative bird for stately homes. It hasn't gotten very far from where it was released (southeast England), and have seen it only in Norfolk and in a few areas in southwest London; this is the opposite of the Canada goose (Branta canadensis) of course, which has spread all over the country, displacing native species and being an all-round nuisance and even a cold-blooded killer (I once witnessed a Canada goose drown a coot chick just for the fun of it).

Monday 1 December 2008

Photo of the Day #21: Rothschild's Giraffe Silhouette

Rothschild's giraffe
Giraffa camelopardalis rothschildi Lydekker, 1903
Giraffidae; Cetartiodactyla; Mammalia; Chordata
London Zoo
November 2008

On a gloomy, rainy November day in Camden, where would a giraffe rather be than inside?