The Zoology Practical Book Cover

Righto. For those of you who have not seen this, here it is. This is the front cover of a zoology practical book that that I did in 2007. In university zoology units, it is often expected that sketches and notes of specimens, especially dissections, are taked for future reference. These drawings are ink and coloured pencil on cream card and are covered in adhesive plastic used to cover books to protect them from wear and tear. In this case, the drawings are protected from being soiled or smudged and also waterproofs the card. Now for a little something about the critters...

In the top right we have Ektopodon serratus, an unusual possum recovered from Early Miocene deposits in Riversleigh of Central Queensland and from Lake Ngapakaldi in the Tirari Desert of South Australia. Once this thirsty, arid land was covered in lush rainforest and was home to a multitude of possums. Little more than the peculiar teeth of this possum is known and those teeth were so unusual that they were once attributed to a monotreme. The molars have many cusps in two transverse rows and these have caused much confusion as to what this animal ate. So far it is thought they consumed food items that needed thorough chewing or crushing, such as nuts, seeds or insects with hard exoskeletons like beetles. Judging by the proportions of the palate and the teeth rows, as well as looking at related species like Chunia illuminata, it is thought that Ektopodon had a short snout and large orbits with the possibility of binocular vision. If this animal was still alive today I think that it would have that cute factor koalas have that make people's hearts melt into fuzziness. This would especially be the case if they were really fluffy looking like the Green ringtail possums (Psuedochirops archeri) of the Top End. I think that they would look a little like a weird cuscus and I did find a photo of the blue-eyed phase of the Common Spotted Cuscus (Spilocucus maculatus). The creamy, soft fur and the eyes sparkling back like sapphires just seemed right.

The Marsupial Lion, or Thylacoleo carnifex, is one of the most difficult animals to draw well in my opinion. I think that is this because it has many features that make it look like a felid and perhaps other things too, like possums and koalas, but it also has some very unique anatomical structures. As a result, we have one very strange looking beastie. To produce this image I found a photo of a mounted skeleton with the skull in a three-quarter view (google "Thylacoleo" images and you'll probably find the image I used) and I layered the muscles on after the method Mauricio Anton in the book he illustrated for Alan Turner. It is called The Big Cats and their Fossil Relatives. Firstly I filled in the temporalis and masseter muscles which are the ones that work the jaws. Thylacoleo had a very large fossa temporalis, through which these powerful muscles inserted, providing the animal with a very savage bite. (Steve Wroe wrote a lot about this). To bring this point across, I made these two muscles very bulky, so they bulge out over the zygomatic arch; think about the jaguar which as the strongest bite for it's size of any extant felid. Next I rounded out the whisker pads that would have sat in from of the bulge of the premolars. I had a look at the infraorbital foramen of Thylacoleo and I decided it was comparable to felids. This hole allows the nerves to pass through the skull to feed into the nerves linked to the whiskers. Cats have a large infraorbital foramen that feeds a dense bed of nerves in the whisker pads making this structure look bulky. Therefore, I ensured that Thylacoleo was well-endowed with good, dense whisker pads. The teeth were pretty hard to draw right and this animal as an unusually broad face due to the premolars projecting out to the sides more than usual. Wroe has suggested that it used its long, blade of its third premolars to bite at its prey rather than just relying on it's incisors to stab its prey to death. Naturally, when its snarls as I have illustrated it here, it should be able to expose them. For the coat I drew from the African leopard (Panthera pardus) for the sandy-orange ground colour and from quolls for the white spots. Leopards can often have green eyes. It is thought that this animal relied on stealth more than anything else to hunt, perhaps like a modern leopard. The structure of its feet are quite possum-like and it probably had a plantigrade stance, meaning that it could not run fast. However, it was probably a good climber and perhaps hunted more like an ocelot (Felis pardalis). This South America cat's modus operandi is to sit on a tree limb and wait for unsuspecting prey to pass underneath. It this instant it pounces onto it and dispatches it. It is intriguing because it suggests that Thylacoleo could have been the inspiration for the legend of the "drop bear" in Australia and indeed in life it would have had a stocky build a bit similar to one.

Zygomaturus trilobus is at the bottom of the piece. It was a diprotodontid, hence in the same family as Diprotodon optatum but in a different subfamily; the Zygomaturinae. They were characterised by complicated upper premolars that could have up to five cusps. They were browsers and inhabited rainforest up until the Pliocene when they dried out, after which they inhabited wet and dry sclerophyll forest. Pleistocene Zygomaturus articulated remains have been recovered from Tasmania. These are nearly complete, meaning that it is the best known taxa of it's lineage. "Trilobus" means "three-lobes" and this refers to three knobs located on the snout. It has been speculated that these may have supported keratin horns similar to those seen in rhinoceros today. These knobs do resemble the bony cores of rhino horns and I searched for pictures of rhinoceros to see what I could find. Since I only had profile photos of all the specimens my judgement was hindered but I decided that the shape of the Zygomaturus nasal knobs resembles those of the Indian Rhinoceros (Rhinoceros unicornis) the most. Therefore I gave it a small single nasal horn. I also gave it an upper lip similar to the black rhinoceros (Diceros bicornis) because it too is a browser. It made sense fro this animal to have pliable lips and perhaps a prehensile tongue to reach leaves above it.