PalQuiz 5

It was months ago since the last PalQuiz, which is a shame in hindsight, as I realise it could have been useful revision for my end-of-term exams. Now, however, I think it is about time I sit down and contemplate once again how to make evil, tricky questions for my beloved readers.

I will try to give good answers to the previous quiz, although I may not quite remember the purposes of many of the incorrect alternatives. I usually have a plan with each one of the four options; they are meant to fool you in different ways, make you think twice, and again, and one more time before you feel sure of the answer. That is always my aim.

1. Toothless (edentulous) beaks were actually very common among dinosaurs, mostly so among the ornithischians (bird-hipped dinosaurs) – that is why I chose most of the options from the saurischian (lizard-hipped) group. (If this confuses you, ignore it… this is not important for understanding the answer.) Gallimimus and Therizinosaurus are both theropods – members of the clade containing all carnivorous dinosaurs, plus a few herbivorous and/or omnivorous exceptions – and these evolved toothless beaks designed to process plant food rather than meat. (Actually, Gallimimus’ diet has been debated for long, and it might be safer to theorise that it was actually an omnivore… but it had a toothless beak nevertheless). Edmontosaurus is the typical duck-billed hadrosaur ornithopod, with beautifully advanced tooth batteries in the cheek region, but the front of the mouth had no teeth and formed a beak for raking in leaves and fruits from bushes and other low-growing plants. Diplodocus was also a herbivore, with the front region of the mouth serving the same function: taking in plant material. However, it had a completely opposite design: in the front of the mouth, all its long, pen-like teeth were concentrated, arranged so they interlock much like the fingers of your hand (they were interdigitating, in fancy words). These teeth would close around branches of shrubs or tree crowns, so that when the mouth was pulled back, they would scrape off leaves and seeds, which they then swallowed.

2. Well, I kind of gave you the answer for that one already… Therizinosaurus is one of those theropods that was assumed to be a carnivore when it was first found, simply because it belonged to the carnivore group. However, subsequent information about its diet pointed more and more toward it being a strict herbivore instead. It’s toothless beak and bulky belly hint toward a plant diet. It’s fossilised faeces have been showed to consist of plant material. Therizinosaurus had huge hand claws, but that is no evidence that it killed and then consumed other animals: the claws may very well be weapons solely for the purpose of defence.

3. I admit this was a quite evil one. If I was asked that question, I might not know where to look even! A good rule of thumb, however, is to always start looking at the head – that is where most of the unique features usually are. However, recall that I enjoy tricking you? I do not expect anyone to know the detailed skull characteristics of these dinosaurs. There is an easier way. If you study the options, you will realise that only one of them is an ornithischian. There is then a very simple way of testing whether this dinosaur is an ornithischian and therefore surely a heterodontosaurid: look at the hip bone arrangement! But… the problem is that on this picture you cannot really tell for sure whether it is a saurischian or ornithischian hip. So it does not work! You have been side-tracked! (Mwuahahaha I’m evil!) So… we have to look at the skull anyway. If you zoom in on it, you notice no extravagant head ornaments that can give you a clue. The next best thing is the teeth. In this dinosaur, the cheek teeth look blunt and packed tightly together, just like a typical advanced ornithischian, but there are also two large fang-like teeth in the front, more typical of a carnivore. However, recall from the previous answer that a weapon (such as fangs) is not necessarily evidence that it is a carnivore, as the definition of a carnivore is that it consumes meat. So, the teeth point (haha, what a pointless pun) toward this being a herbivore, but this is not precise enough as there are two herbivorous dinosaur groups as options: B and D. It then really comes down to knowing your stuff – i.e. being aware of the characteristic teeth of these dinosaurs. Ooops, it seems like you did need to know details of the skull to puzzle this one out. I wonder if I should top the evilness of this question by just not giving the answer? Yes, yes… I’ll do that. *rubbing hands maliciously*

4. The encephalisation quotient, commonly shortened EQ because it is such a mouthful, is an indirect estimate of the intelligence of any craniate animal. However, the EQ is actually measured as the brain size relative to and ‘expected’ brain size for the size of its body, which is determined by using a typical mammal for reference. So, basically, you take the brain size of an animal and divide it by the brain size of that standard mammal, and this gives you the EQ. I noticed now that I had written “head size” instead of brain size, so C may not strictly speaking be correct, so I would not judge you to be wrong if you chose D. D was meant to be the incorrect alternative that fools those who have a faint idea of what EQ is but are unaware of what it actually measures… but my silly mistake means that those who opted for D instead know better than me!

5. All the statements except for the first one are true (to the best of my knowledge)! That first statement was really the only one that was meant to be tricky – Othniel was called Charles Marsh, not Carl Marx, which was the Russian economist that founded the communist ideology.

Now on to the fifth PalQuiz!

1. The phylum name Brachiopoda means…?

A. Branching foot

B. Arm foot

C. Long foot

D. Tall foot

2. Which of these echinoderm groups is extinct?

A. Ophiuroidea (‘brittlestars’)

B. Crinoidea (‘sea lillies’)

C. Cystoidea (‘crystal apples’)

D. Echinoidea (‘sea urchins’)

3. The ‘egg thief’ dinosaur Oviraptor is actually poorly known. Paleontologists have only found a single, fragmented skeleton. On which other close relative is the bulk of our knowledge on the oviraptorid group based on?

A. Citipati

B. Ingenia

C. Gigantoraptor

D. Yulong

4. Mammals evolved from a group known as the ‘mammal-like reptiles’ (synapsids), which can be thought of as intermediates between ‘reptiles’ and mammals. Which is the main feature that marked the emergence of the first true mammal? (i.e. what made it a mammal rather than a mammal-like reptile?)

A. Fur

B. Hair

C. Middle-ear bones

D. Milk (lactation)

5. Which of the below is currently one of the leading paleontologists involved in the discoveries and research of the vast wealth of bird-like dinosaurs in China?

A. Robert T. Bakker

B. Xu Xin

C. Paul C. Sereno

D. Zhao Xijin