Wednesday, July 14, 2010

A New Look for Triceratops

Alright. I know I have not posted in, like, 3 weeks, but I have been...busy....and lazy. I mean, I had this blog done a week ago but didn't get around to inking the stupid cartoon until today. XD Not the best cartoon either, BTW. I spent about 10 minutes drawing it and 5 inking it. Totally wasn't in the mood to actually try. Anywho, let's get on with it.
Today we are going to take a break from the lemurs (we'll come back to them....later) to check out the new look of one of the most famous dinosaurs: Triceratops.

Traditionally, Triceratops is depicted as a dinosaurian cow, living in massive herds mowing up plant matter with their beak. Now, I'm going to throw a curve-ball at you and say that Triceratops was actually a prickly, anti-social beast that would eat just about anything. Let's look at the evidence.

First off, why prickly? A well known ancestral species of Ceratopsian (the group that includes Triceratops) called Psittacosaurus (here) was recently discovered to have a rather spiny tail. This means that the ancestors of Triceratops likely had spines on their tail which means it may have also had them. Solidifying the possibility of Trikes having spines was the discovery of Tianyulong (here), an even fuzzier dinosaur. Tianyulong was incredibly important because it lived even earlier than Pisttacosaurus (although it likely wasn't ancestral to Trikes, it is a close relative of the ancestors). This means that spines/fuzz are a very early feature among bird-hipped dinosaurs (a large order of dinosaurs that includes Ceratopsians, duck-bills and Stegosaurus). Thus, Triceratops may have had prickles. Plus it likely had knobbly skin like a crocodile based on skin impressions of close relatives like Chasmosaurus. Now, I am ready to here people say "BUT SCOTTER, IT LOOKS STOOPID NOW!" Well, get over it. People said that about feathered raptors but it doesn't make it any less accurate.

Alright. Now we get on to the biggest change in Triceratops.....wait for it.....It may have actually eaten meat! This is based greatly on the fact that their jaws are built like a carnivore. They have a bite designed for "shearing", which is a feature typically seen in meat-eaters. However, Trikes and their kin likely were not strict carnivores like our old friend T. rex. The belly of Triceratops was incredibly large and likely was designed for breaking down plant matter. Thus, Trikes mostly ate plants, but would have eaten meat on occasion. Basically, think of them as a giant wild boars. ;) I have heard of some evidence of a Ceratopsian feeding on a carcass, but I have yet to verify it yet, so I do not know for sure.

Next on the agenda, Triceratops social structure. Now, numerous relatives of Triceratops are known from bone beds that show they lived in herds (Psittacosaurus, Styracosaurus, Centrosaurus, Pachyrhinosaurus) however, none of its very close relatives (Torosaurus, Chasmosaurus, Eotriceratops) have shown evidence of living in large herds. Now most families of animals show great variation in their social structures, even among animals in the same genus. My guess, is that Triceratops and its kin were far less social than we originally thought, mostly because they only had one real predator: Tyrannosaurus rex. No other carnivore in their environment would dare attack an adult Trike. Why do animals live in herds? For protection. Well, an adult Triceratops would not need much protection. This is mostly my theory, but I am sure others would be inclined to agree.

Anywho, that is all for Triceratops. XD The next blog will be on the giant extinct insects of Scotland. Why? Because I am off to Scotland in 10 days and I feel like celebrating!

Tuesday, July 6, 2010

Gordon the Proto-Aye-Aye

Well, it is decided. Gordon the Proto-Aye-Aye will be the offical mascot for the blog. Expect to see a banner with him on it because that is just how I roll.

Monday, July 5, 2010

A Diverse Family: Lemurs Part II

In the last post we went over what defines a lemur as their early evolution prior to reaching Madagascar. Now I'm going to cover their diversification after they reached the island.

As I said before the aye-aye lineage broke off from the lemur family tree first, pretty much as soon as they colonized Madagascar. Now, lemur evolution and cladistics (the study of how organisms relate to each other based on evolution) are somewhat debated. I'm going to try to use the most accepted theories to help explain here, but there are always some experts who will disagree.

Extinct members of the aye-aye family are very few and very fragmentary, but one in particular has gained some attention. It is known as the giant aye-aye, and I'll be damned if this aye-aye wasn't giant. The modern aye-aye usually weighs about 3 kg (6.6 lbs) while the giant aye-aye (Daubentonia robusta) was 9 kg (18.2 lbs). That thing would be effing scary! Very little is known about this creepy motha-effer but it likely lived much like its modern relative.

After the aye-aye, the first lemurs to diverge were the ones that most consider the "true lemurs". Ring-tailed lemurs are the classic example of these guys, but they also include critters like the ruffed lemurs, the bamboo lemurs as well as the various kinds of brown lemurs. One particularly large genus of these lemurs existed until about 1200 AD which was called Pachylemur which is also called the giant ruffed lemur. The two species in this genus were about 3 times larger than the average ruffed lemur at about 13 kg (29 lbs) and likely had very similar diets, feeding on flowers, fruit and leaves. For many years it was thought these lemurs were ground-livers (terrestrial) that were easily hunted by the first people of Madagascar, however, recent studies have shown Pachylemur were likely tree-livers (arboreal) like its modern relatives.

Although Pachylemur were quite large by lemur standards there was a completely extinct sister family to the true lemurs called the "koala lemurs" which have some of the largest lemurs ever. They are called as such because they have short limbs and bodies that greatly resemble koalas. The only genus in this family is Megaladapis, which contains three species, the largest of which, Megaladapis edwardsi, was about 1.5 m (5 ft) long and 50 kilos (110 lbs) in weight. Much like a koala, its limbs were well developed for vertical climbing, and likely would have been a very chill animal. It also had an incredibly thick skull with powerful teeth and incredibly powerful jaws that it would have used to mush up any plants within reach. Megaladapis also had a rather strangely built nasal cavity which actually looked somewhat like a rhino. This confused scientists at first but now most believe that it had a prehensile lip, much like some kinds of rhinoceros. This would have helped it grasp plants without letting go of a tree trunk. Another interesting fact about these big guys is that they were once grouped within the sportive lemur family. This was mostly because they have rather similar teeth. However, genetic evidence (which tends to trump pretty much all other evidence) puts them closer to the true lemurs.

Speaking of sportive lemurs, they were among the next two groups that split from the main lemur tree, along with the mouse and dwarf lemurs. Fossils of these critters are rare, mostly because they are so damn tiny and fossils of tiny animals do not tend to fossilize. The modern representatives of this group are all nocturnal and likely look very similar to the ancestral lemurs that first reached Madagascar. They include the tiniest primates in the world, Madame Berthe's mouse lemur, which averages at 30 g (1.1 oz), as well as some of the most recently discovered.

The next group is typically called the "monkey lemurs", and this is because they had habits that were rather similar to modern baboons and macaques (thus I usually call them baboon lemurs to make it more specific). These lemurs were generally large (about 35 kg) and mostly ground living, making them very similar to baboons. The most specialized species was Hadropithecus stenognathus which had an incredibly shortened skull that made it seem almost ape-like in its facial appearance. Its body was compact and its legs were short and stocky, clear signs of a terrestrial (ground living) animal. The shortened skull and grinding teeth were well adapted for grazing on grass, a diet that is rare among primates and is best known in the gelada baboon of Ethiopia. Hadropithecus would likely have been seen shuffling around the hills of central Madagascar plucking grass with its dexterous hands and munching the plants to a pulp. This species group is probably the least studied of all the fossil lemurs, and much more research is likely to be done in the future.

The final groups that diverged were the extinct sloth lemurs and the modern sifakas. Sloth lemurs are so named for their likely habit of hanging from branches like a modern sloth. They had highly flexible hips and shoulders that allowed for some rather interesting ways of hanging whether it be upside down or from one limb, sloth lemurs could do it all. The largest of these species was Archaeoindris fontoynonti which weighed about as much as a modern gorilla; 200 kg (440 lbs). Unlike gorillas, Archaeoindris likely spent almost all of its time in the trees and moved much like an orangutan, swinging slowly from branch to branch in search of fruits and leaves.

The final group we are going to talk about is my personal favourite family of lemurs, the sifakas (pronounced shif-ahk) and their relatives. These guys are known for their rather classic lemur appearance, but unlike true lemurs, they travel on two-legs when on the ground by hopping somewhat comically. From what I've gathered no extinct species of these cool leapers have been found, but they are closely related to the gigantic sloth lemurs.

So, what exactly caused all of these lemurs to go extinct. Every extinct species I have mentioned was gone from the Earth in the last 2000 years. This is comparatively recently when you think about other large mammal extinctions (eg. the sabretoothed cats) so from the very beginning man kind was thought to have been the cause and it sis very likely over-hunting was the main culprit in their demise. In fact, almost all large animals of Madagascar went extinct almost as soon as man arrived, including elephant birds, giant fossas and dwarf hippos.

So that is all on lemurs for the next little while. Hope you weren't bored to death by all of this but I also hope you learned something. =P Next we'll take a closer look at each extant (living) lemur group.

Oh, and BTW, I think I've decided to make Gordon the Proto-Aye-Aye the mascot of my blog, so you'll probably be seeing lots of him. XD

Sunday, July 4, 2010

An Island Arrival: Lemurs Part I

Over the last couple of days I have been delving into the world of one of the weirdest groups of mammals, the lemurs. Lemurs are usually mistaken for monkeys when people first see them, although I am not exactly sure why since I really only see similarity in their hands and feet, which both have opposable thumbs/toes. I mean, they have long snouts, furry ears and whiskers. They basically look like cats with fingers, especially when you consider some species even purr and meow like a cat. Don't get me wrong though, lemurs are relatives of monkeys and apes, but are a very distinct group from our simian friends.
The most important distinction is their wet nose. This is because primates are split in to two groups, the ones with wet noses and the ones with dry noses, and lemurs certainly fall in the wet nose category. A wet nose is very important to them too, because unlike the dry-nosed monkeys who communicate visually, lemurs use smell to give signals to each other...which is another similarity to cats. O_o The other features of lemurs are their interesting grooming devices (sounds kinky for some reason). The lower incisors of lemurs form what is called a toothcomb, which is exactly what it sounds like; a comb made from teeth. It is used to help groom the fur and is only found in lemurs. The other grooming device of lemurs is their claw. Four of the lemur's toes have nails on them, but the second toe has a large claw on it which is officially known as the "toilet-claw". I know, I laughed when I first heard it too. It is called this because when it was first named the term toilet meant "personal grooming", not the...can. Anywho, the toilet-claw is primarily used for raking through the fur, usually in places the lemur cannot reach with its toothcomb. The only lemur without a definitive toilet-claw or tooth comb is the aye-aye, which is not suprising considering how damn weird it was anyway. I mean, look at this thing! I'm going to go into a little detail on aye-ayes just to explain how strange they are. Aye-Ayes are commonly called "primate woodpeckers" because they are adapted to breaking in to tree trunks and extracting yummy beetle grubs. They do this first by tapping on the bark with their creepy, skeleton-like fingers and listening with their big-ass ears to see if their is a hollow spot in the tree. When they find it they use their chisel teeth and rip through the bark then shove their ridiculously long middle finger into the hollowed cavity to extract some nice delicious larvae.
Anywho, seeing as this is supposed to be about prehistoric animals let's move on to the extinct forms of lemurs. Lemurs evolved about 55 million years ago (although some studies suggest about 10 million years earlier) which was right after the dinosaurs went extinct when the world was on the rebound from all of that death and destruction. The fossil record of early lemurs is somewhat crappy, mostly due to rocks of this time are rare in Madagascar (where all lemurs are found today) and Africa (where lemurs originated).
One big problem in lemur prehistory is exactly how they reached Madagascar. The island broke off from Africa about 160 million years ago, which is waaaay before the first lemur appeared on Earth. This means that they sure as heck did not evolve there, especially when you consider the earliest lemur fossils are known from Africa.
So how did these tiny primates get across 560 kilometers of water? It is generally thought that they took a boat. No, really. They did. Most scientists believe that lemurs hitched rides on rafts of matted plants and sailed across the Mozambique Channel to their lovely island home. For most mammals this would be a nearly impossible task, but some species of lemur (which are also among the most primitive) have the ability to lower their metabolism in a manner similar to hibernation. This means they could have napped the entire trip and landed on the island safe and sound. This whole process likely took place about 40 million years ago (although, once again, other scientists say otherwise and suggest an earlier arrival of 60 million years ago).
After reaching Madagascar lemurs found themselves in a perfect world, with literally thousands of niches to fill. The first group of lemurs to split off from the main family was the group that eventually lead to our messed up friend, the aye-aye. This was pretty much as soon as the ancestral species reached the island.
Yes, I can picture it now. The wacky cousin proto-lemur gets off the boat and starts scratching and gnawing at the bark to eat the beetle grubs while the rest of the family just is glad to get rid of him. XD
Anywho, this is only part one of my little adventure into the history of lemurs. Next up will be stuff on the lemurs diversification following their arrival on Madagascar!

Saturday, July 3, 2010

Sabretoothed Kittehs R Teh Kewlesht

I think the perfect way to start off this blog is with a little bit of information regarding the coolest prehistoric creatures (IMO), the sabretoothed cats. Fist off, I would like to say that they were not tigers. Sabretoothed cats were about as distantly related to tigers as a cat can get, so if I catch anyone saying tiger when referring to any kind of sabretooth I will smack them.
First off, let’s take a look at what makes these kitties famous: their badass fangs! Most, if not all known sabretoothed cats had upper canines that protruded out from the lips. However, these fangs were actually very delicate and would break if they hit bone. This means that the cat had to bite in a soft spot in order to do any damage. There had been suggestions that the cat would have bitten into the belly and let the prey bleed out (kinda like a great white shark) but this hasn’t really been a well accepted theory. Most scientists believe that the sabretooths would have bitten into the neck, severing the jugular allowing for a quick death. It is also important to mention these teeth were not used to randomly stab the victim in the neck like a psycho murderer. The cat would carefully place its bite using its whiskers to help guide it then
So sabretoothed cats first appeared about 23 million years ago and went extinct at about 10’000 years ago. All of these species were within the same subfamily in the cat family. However, the sabretoothed cats can be split again in to three more groups which I usually call the scimitar cats, the dirk cats and the false-saber cats. The first group I want to talk about is the false sabretooths. This is probably the least known of the group includes animals like Dinofelis and Metailurus which looked a lot like modern jaguars mostly because they were short legged and stocky and they also had rather small teeth compared to other sabretooths. In fact, their teeth were barely even sabers. They were only slightly flattened and were kind of in the middle of being conical and blade-like. Thus I (and most people who use laymen’s terms for them) call them false sabretooths cats. Although they did not have incredibly long teeth like other sabretooths they were pretty incredible on their own.
Dinofelis is particularly interesting because it has been found alongside the bones of its possible prey. In South Africa Dinofelis bones have been found alongside those of baboons. Now, an interesting fact is that baboons are badasses. They are known to kill predators like cheetahs, usually by mobbing it and then biting and smacking it until it dies. Kind of scary. This means Dinofelis likely had its hands full when dealing with these psycho monkeys. To make matters worse, there were also several species of giant baboon at this time, including an herbivorous species the size of a gorilla and an aggressive man sized one. But Dinofelis could hold its own thanks to its massively built shoulders and arms which it would have used to combat those rambunctious primates. Other species Dinofelis shared its habitat with some 4 million years ago were freaky backward tusked elephants and our earliest ancestors.
The second group of sabretooths is usually called scimitar cats. I don’t really see why they are called this considering a scimitar is typically a really huge curved sword and scimitar cats typically have rather small teeth when compared to the dirk cats, but whatever. These kitties are some of the oldest of the sabretooths and also among the last. The earliest members of the family hardly looked different from the classic cat except they had slightly larger than average canines. However by the end of their time on earth the scimitar cats had become highly specialized, with two species existing; one called Xenosmilus (of Florida) and another, Homotherium (of pretty much everywhere but Australia and South America).
Xenosmilus was a stocky cat that probably looked somewhat bear-like thanks to its short build. It also had some of the ugliest teeth ever seen on any cat. Xenosmilus is known from relatively scarce remains, but it is known that it likely preyed on peccaries (a type of pig-like animal) which have been found in the same area. Peccaries are rather aggressive animals, so Xenosmilus likely evolved its stocky limbs to tackle these piggy’s to the ground then bite through their neck.
Homotherium (yes, it’s name has homo in it…grow up) was pretty much the opposite of Xenosmilus, with long limbs, a short tail and a sloping back that made it look somewhat like a hyena. Other than Smilodon (a dirk cat), Homotherium is the best known sabretooth; it is known from hundreds of fossils from Africa to Mexico. The best known species was Homotherium serum from North America. A cave in Texas is thought to have been a lair of this species and even has the bones of there last meals: young mammoths. The biggest mystery is how the hell the bones got there. Homotherium’s teeth were too delicate to drag the carcasses or bones in to the cave, so the only other possibilities are that wolves dragged them there are the Homotherium stole their food, or the mammoths went into the cave and then were killed by the scimitar cats.
The last group was the dirk cats, which are pretty much your classic sabretoooths; big shoulders, short tail and huge teeth. The most famous of these guys (and my personal favourite extinct animal) was Smilodon, the largest of all sabertoothed cats. There were three different species of Smilodon, ranging from Alberta to Argentina. Two of the species are particularly well known, Smilodon fatalis of western North America and Smilodon populator of south-eastern South America. Smilodon fatalis is probably the best known fossil cat in the world, with literally thousands of specimens collected from the Rancho La Brea Tar Pits of California. It was a pretty big kitty, weighing in at close to 280 kg (620 lbs) and had massively powerful forelimbs. Also, it is thought that this species was likely a social hunter, although there is no conclusive proof.
If you thought Smilodon fatalis was big, just look at Smilodon populator. Even its name is badass: “the devastating knife tooth”. At 500 kg (800 lbs) Smilodon populator was one of the largest cats ever to live, only exceeded by the American lion (Panthera atrox). In order to imagine this monster you basically have to take a lion, shorten its tail, turns its canines into samurai swords and give it steroids. I mean, this thing was an effing tank! Picture Brock Lesnar mixed with a tiger. That is what Smilodon populator looked like. And this guy had to be. In South America during the Ice Age the prey was crazy. Some of the most common animals were giant ground sloths, and they sure as hell would need one badass cat to take them down, and Smilodon populator was well equipped. Even then, in was no match the ultimate enemy: extinction. At the end of the Ice Age, Smilodon and all the other sabretoothed cats went extinct. It is not known for sure what wiped them out, seeing as most theories have one thing or another wrong with them. I personally do not dwell on what wiped them out, but I certainly like to imagine what they would have looked like.

And so that is my first real blog…feel free to comment, and by that I mean COMMENT DAMN IT! Oh, and BTW, I tried to add some more pictures but my computer is being stupid so...yeah.

Friday, July 2, 2010

Welcome to the World of One Weird Kid

So. First blog. Evah. Kind of makes me feel like an even bigger nerd than I am. Anywho, this will be where I blab on about things relating to prehistory or zoology and it will hopefully be put in a way that most teenagers could get the jist of what I am saying. I mean, for crap sake, I am a teenager too, and I personally find a lot of big science-y words boring. So for the most part I'll try to keep things kind of simple, but if I go technical on you, please do not hesitate to ask questions. Finally, I would like to add I am in no way an expert on any of the subjects I'm gonna be talking about. If you find an inaccuracy, just tell me. Please do not be a giant doosh and be all like "yo rawng bee-yach!"