Welcome to my Metazoic site! This site discusses the existence of the creatures to come along after humans will be extinct. I first became interested in a world after man when I acquired my first copy of Dougal Dixon's After Man: A Zoology of the Future in 1992. However, I unwittingly created creatures that did not exist from the time I was about 8 years old. But it was after I obtained a copy of that book (now a collector's item) that I decided to take these same creatures I created as a child and make them more realistic in an evolutionary sense. Though it may be hard for a lot of us to grasp, humans will soon become extinct. One of the biggest factors of how this will happen is the current overpopulation rate. Which is why I don't contribute to the population. I created this world with little more than mammals fulfilling all ecological niches with the help of some friends. I even gave the era of the age after man a name, I called it the Metazoic, derived from the words for "After-era" (Meta, meaning after, and zoic meaning era). We are now in the Cenozoic era. To view all the animals I have created since I began this project, you can go to the "Meet the Mammals" section of this site. To discuss your own ideas about what you think will happen in the future world, and share your ideas with others, please feel free to leave a comment.
One more thing, some of you may find this site quite offensive, and you have a right to your own opinion. But please respect my right to have an opinion too. I'm not saying there is no GOD, I believe it was HIM who got the ball rolling. But I believe after that, evolution took over. There is so much more evidence of evolution than there is of creation. Even that going on right under our noses. Other than that, enjoy yourself and visit our many links.

Wednesday, April 29, 2009

Animals That Play Dead Risk The Lives of Others

I thought this was an interesting article here, animals that play dead risk getting others killed. I know some animals like opossums play dead, that's what they are famous for. Often, like all other animals that put on the same act, they smell dead too. This makes them unattractive to predators. That's the whole purpose. Not too complicated! But this article talks about how the same act that saves the opossum just puts other animals at risk of being hunted. That could be why opossums have survived for so long. Even though other seemingly smarter and better adapted mammals have gone extinct. It says humans also fein death. I don't know I never have, and I wouldn't think such an act would work if you are being attacked by another person.

Anyway, here is the article:


Animals that Play Dead Sacrifice Others
Jennifer Viegas, Discovery News

April 29, 2009 -- Many insects and animals, including humans, enter into a state of "fake death" immobility when threatened, but this seemingly passive frozen-with-fear state may be a selfish behavior that can lead to the killing of one's friends and relatives, according to a new study.

For humans, this can happen when an attacker enters a building and starts randomly targeting victims. People who play dead often survive, while their fleeing colleagues usually aren't so lucky.

The paper, published in the latest Proceedings of the Royal Society B, is the first to demonstrate the adaptive significance of playing possum, and how it's a selfish behavior.

"Death-feigning prey increase their probability of survival at the expense of more mobile neighbors," lead author Takahisa Miyatake told Discovery News.

Miyatake, a professor in the Laboratory of Evolutionary Ecology at Okayama University, and his team focused on a predator-prey system that, like the cartoon Road Runner and Wile E. Coyote, involves constant chasing. In this case, a hungry jumping spider frequently chases, bites and eats red flour beetles. The two species cohabit on rice bran or corn flour in cereal storehouses.

The researchers conducted experiments to see how well death feigning beetles survived when alone, or with other individuals either of their own, or similar, species. The scientists also checked to see if chemicals emitted by beetles playing dead somehow made them unattractive or unpalatable to the hungry spiders, which were starved for a week before the experiments began.

The chemicals didn't seem to make a difference, but having other moving individuals around did. During one experiment, around 60 percent of the beetles were eaten by the spider when they were alone and playing dead versus just 9.6 percent when additional mobile insects were nearby.

"Spiders appear to rely on prey locomotion in order to catch prey, and in addition may rely on tactile movement signals to initiate the kill behavior," the researchers explained, adding that "selfish prey" playing dead then wind up sacrificing their "neighbors in the group or community."

They suspect the findings could also apply to caterpillars, moths and other beetles that live in food storehouses. Sheep, group-living snakes and even humans may also fit the scenario.

"We can imagine such a (death-feigning) person might survive more," Miyatake said, referring to war, or war-like conditions.

He added that not everyone immediately goes into the play dead mode, however, probably due to each individual having either a "shy or bold" personality, which is partly controlled by his or her genes.

Something similar happens among fire ants, according to Deby Cassill of USF Petersburg's Biology Department. She and her colleagues observed how different aged fire ants acted when they were under attack from neighboring colonies.

"Days-old workers responded to aggression by death feigning, weeks-old workers responded by fleeing, and months-old workers responded by fighting back," Cassill and her team determined.

The older ants might have died holding down the fort, but they were four times more likely to perish than the younger ants that simply went into a catatonic state. Age and assessment of personal strength might therefore come into play when an individual has no choice but to flee, feign death or face the enemy.

Monday, April 27, 2009

The Family of the Week: The Tapimurids

These animals were inspired by Dixon's tapimus, presented in After Man, and the Shag-rats presented in The Future Is Wild. I took the two, did a little tweaking with their anatomy and made them my own, putting both together in this family. Though I did decide to keep the names. They are descended from modern rats, and instead of making them like they appear in Dixon's creations, I made them look more like great dane dogs. Only pudgier. Since rodents do have the long incisors, I had to keep the square shaped muzzle. The ears are larger and more pointed in the genus Tapimus, but smaller and more rounded in the shag-rats (Lasiomus). If you get a good look at the modern maras, you could get a great idea of what I figured these animals to look like, only with tails in tact. The tails are not long, it reaches just past their hocks, and it's enough to keep the animals well balanced when trying to make a quick get-away. The necks are not very long, but not very short. The legs are long and slender. When resting, these animals sit on their hocks, rather like kangaroos, with the tail resting on the ground. The eyes are large and almond-shaped. There are no naked feet-pads, but rather hoof-like feet instead of soft pads. The length of the toes are greatly reduced to compensate the development of hooves.

These animals live in groups, except for the Amazonian tapimus, which lives in couples. Usually a male, female and sometimes a single young. The young tends to stay with the mother, and the male usually parts company. Tusks are present in males, but lacking in females. However, to defend her baby, a female is equipped with sharp claw-like hooves to slash at a predator. Males take over defending the family when the couples are together, then he can gore a predator with his tusks. These rats are vegetarians. They feed on grasses, leaves, berries, fruits, plants and flowers. They feed during the day and roost at night. In shag-rats, they live and breathe in large herds, led usually by a dominant male. There is a species that lives in colder climates, and their fur even changes with the climate. They turn white during the winter and brown and white during the summer. This makes them almost invisible to predators, or at least would confuse the predator. They find their biggest safety in numbers. This is why their groups are so large, about 100 individuals sometimes. Not all related to the dominant male usually. Their biggest defense is to run, and run they really can! These animals can reach speeds of up to 50 mph, and can reach these top speeds in about a second.

Predators of these animals include the largest mongooses, Phobogulus, foxes, snakes, crocodiles, predatory pteropods, and even large Barofelids. Phobogulus particularly specializes in hunting such animals as Lasiomus. Such animals as foxes prefer to take the young of Tapimus. They are hardly deterred by the defensive mechanisms of the adults.

Thursday, April 23, 2009

Vampire Math!

I don't usually talk about the famous (or to some, infamous) blog Pharyngula, since I try to talk more about the science of paleontology and evolution here, rather than the current political and social battles the scientific theory (which is not the same as one getting drunk one night and coming up with something) is facing in the United States. Not to mention PZ Myers doesn't talk much about speculative biology. But recently, he posted something so good I just had to link to it...vampire math.


Basically, Brian Thomas, a theoretical ecologist, decided to do some calculations to try and calculate the overall population dynamics of vampires in Sunnydale based on a bit of predator-prey dynamics in the wild. Now it must be mentioned that these population calculations were done on the aspect of vampires from the Buffyverse, and so are affected by the in-show continuity (the Hellmouth and such), but we can also use most of this to calculate the ecology of vampires in general. Of course no vampires were used in this study, because they either were not found in the universe that the author existed in, or else it would be really dangerous to fit the little bugger with a radio collar to try and track its movements. So instead, Thomas came up with the following equation...

Where in this equation
r = is the intrinsic growth rate of the human population, incorporating natural rates of both birth and death as well as immigration
K = is the human carrying capacity of the habitat in question
a = is a coefficient that relates the number of human-vampire encounters to the number of actual feedings
b = is the proportion of feedings in which the vampire sires the victim (i.e.- this is the vampire birth rate)
m =is the net rate of vampire migration into Sunnydale
s =is the rate at which the Scoobies stake vampires (assumed to be the only important source of vampire deaths).

When we try and plot this data, three different stable equilibria. The first is where the humans become extinct and the vampires, depending on humans for food, die out with them. The second is where the rate of staking is faster than the rate a vampire can sire victims, and so the vampires are extinct and the population of humans is near carrying capacity (the maximum amount of humans the environment can sustain). The third, however, is the interesting one. Setting the two equations equal to each other to find an equilibria, we find that in an average mid-sized California town like Sunndale that the equilibrium population will be about 36,346 humans, and for that many humans there will be an equilibrium of about 18 vampires. In a shocking case of irony, the actual population of Sunnydale within the show is barely a thousand or two a way from this, at about 38,500.

But, as anyone who has watched a single episode of Buffy the Vampire Slayer will know, there are more than eighteen vampires in Sunnydale. A lot more. Therefore, some other factors must be at work in order to account for an unnaturally large population of vampires in a small area, such as...

  1. The Hellmouth Factor. Basically, the hellmouth is a pandimensional back door, a place where the boundaries between worlds are weaker, allowing vampires, demons, and all manner of Eldrich horrors to enter our world. Since the Hellmouth itself is where vampires enter our world, there are two major reasons why the vampire population in Sunnydale would be higher. One, vampires who enter Sunnydale through the Hellmouth will attempt to settle in that area, since that is where they entered this world at and because there is an ample food supply around the immediate Hellmouth vicinity (casually referred to as the greater Hellmouth area). Two, transient vampires who have just entered the world through the Hellmouth will pop up in Sunnydale, and may try to feed before moving on to other areas where they can stake their territory. Hence you get vampires coming in all the time, and artificially "boosting" the population up.

  2. Other Food Sources. One problem with this study is it assumes that humans are the only food source of vampires. However, the large population of vampires in Sunnydale seems to be indicating that the vampires are feeding on other sources of food, which would allow a larger population of resident vampires than assumed from the mathematical models. Cows, pigs, sheep, deer, and dogs are all likely candidates for alternate components of a vampire's diet. In fact, I wouldn't be surprised if they occasionally caught rats and other small animals to supplement their diet. And whoever said vampires had to be strict carnivores. Perhaps they are somehow related to bats, in which case fish or even fruit may make up a part of their diets. These alternate food sources would bring the overall population of vampires up, as an area richer in food allows more predators per square mile.

  3. Metabolism. Something that most people don't realize about blood is that it is very poor in nutrition. Its over half water, and the rest is very low-energy material. The vampire bat, in fact, has to feed every other night or else it will starve on its low-calory diet. because of this, vampires may be low-metabolism creatures, mostly placid and slow, but capable of quick bursts of energy to attak and subdue prey, much like a modern snake. If this is true, vampires may be able to fast and go without blood for long periods of time, thereby increasing the amount of vampires an area can support. If one decreases the amount of times a vampire needs to feed, the population of prey becomes larger and can thus support more predators.

There are also some other isses that, while speculative, must also be addressed because they affect the way the vampire population grows in several ways. These include...

  1. Vampire Mating. One thing this study never really talks about is exactly whether or not vampires are limited to reproduction-via-bite, or whether or not they can reproduce via normal methods (as for what that is....ask your mom). If vampires can reproduce in the usual way as well as through bite reproduction, then the vampire population can grow much, much quicker than through just bite reproduction.

  2. Vampire Parenthood. Another thing that is not talked about is whether or not vampires have any sort of parenthood. I'm not just talking about vampires raising natural born children, but do they act like "parents" to their turned victims, showing them the ropes of vampirism, or are they like fish and just leave their offspring behind, to fend for themelves. These two styles of reproduction are known as r/K selection theories. Animals that are r strategists try to create as many offspring as they can in as much time as they can, but they invest no care in the offspring and thus few of them survive. K selected animals invest time and care in their offspring, and normally these animals tend to live a lot longer than r selected ones. But there is a downside, K selected animals only produce a few offspring at a time. This is another important factor to consider, as it affects the survival rate of vampires in the population.

  3. Other Predators. The Buffyverse isn't just filled with vampires. It is home to demons, werewolves, Eldrich horrors, and the occasional god thrown in for good measure. Most of these have a taste for human flesh, or some other food source derived from humanity. Because these various creatures are competing with the vampires for their food, the vampire population is expected to be lower due to the increased competition. Other supernatural creatures may also add into the death rate, I mean lions go out of their way to kill hyenas on the African savannah.

For those who wish to read the study in its entirety, it can be found here (http://www.hphomeview.com/Tips/Vampire%20Ecology%20in%20the%20Jossverse.pdf). Perhaps someday I will post my own ideas on vampire evolution and ecology, but for now enjoy this facinating thought experiment via a fusion of math and ecology!

Wednesday, April 22, 2009

Walking With Pinnipeds

An illustration of Puijila darwini by Carnegie Museum of Natural History artist Mark A. Klinger

I just heard about this new, great discovery from the Canadian Arctic, Puijila darwini, a new primitive semi-terrestrial pinniped. For a long time, the origin of pinnipeds, seals, sea lions, and walruses, was a highly murky and highly controversial subject in mammal palentology. Some have even argued that "pinnipeds" are a polyphyletic, or artificial, grouping, true seals being closer related to weasels and their kin, while sea lions and walruses were cousins of bears. Lacking good fossils of pinnipeds (especially early ones), Huxley thought he saw a connection between the teeth of modern pinnipeds and the primitive teeth of creodonts, which to him suggested that seals were descendants of these ancient carnivores. This made sense at the time, seeing as there were no good early seal fossils and the other major group of aquatic mammals, the whales, were thought at the time to descend from another primitive carnivorous group, the mesonychids. So for some time, due to lack of contradictory evidence, the idea that seals were aquatic creodonts remained on the books.

Then along came Enaliarctos. First discovered by Edward Mitchell and Richard Tedford in the Late Oligocene-Early Miocene deposits of California, Enaliarctos was a five-foot long pinniped that seemed to be a transitional fossil between the bears and other arctoid carnivores (Hemicyonids). Its skull was more seal-like than bears, with more uniform teeth, but it still possessed the shearing molars that are present in bears, and in fact all carnivorans. Other features also indicate Enaliarctos was somewhat intermediate betweeen bears and seals in features of this anatomy.

However, despite the fact that Enaliarctos shed some light on the origin of seals and sea lions, it did not answer all the questions. Where did seals take to the water? The fact that sea lions appeared in the Pacific about the same time true seals did in the Atlantic seemed pretty fishy for some, and to others it seemed to vindicate the idea of the "pinnipeds" being polyphytletic. Why did they take to the water, what ecological forces shaped their bodies, adapted them to life in the sea? Enaliarctos could not answer these questions, and so the matter lied dormant for quite some time...until the discovery of Puijila

A reconstruction of the skeleton of Puijila by Alex Tirabasso of the Canadian Museum of Nature

Puijila is a rather unusual primitive seal, in many ways resembling a giant otter more than a primitive pinniped. However, it has numerous features that betray its pinniped ancestry
  1. Puijila has four lower incisors, rather than six as seen in most extant carnivorans. However, seals and sea lions today also have four lower incisors.
  2. Puijila's upper end-molars are small and located towards the midline of the skull. This is a strange arrangement for most mammals, but typical of pinnipeds.
  3. Like modern seals, Puijila has a large, well-developed infraorbital foramen, a hole below the eye socket in the front of the skull. This hole allows nerves to reach the front of the skull, and is well developed in species that have well developed or sensitive whiskers...like seals.
  4. While Puijila looks otter-like, it has large eyes, like a seal.
  5. Puijila has long, flattened toe bones, which are typically found in web-footed mammals.
  6. The limbs and tail of Puijila suggest that it swam via its four limbs, like seals and sea lions, rather than a combination of tail and limb strokes, like otters do.

Puijila's otter-like features, on the other hand, can be chalked up to convergent evolution. Because Puijila and otters were inhabiting the same sorts of environments, the sleek, otter-like body plan was the one best. In fact this conclusion is vindicated by other fossils in the fossil record. Potamotherium, another early seal, was once regarded as a sort of otter! However, it must be said that Puijila is not the ancestor of seals and sea lions. Puijila dates from the same time as Enaliarctos, about the Late Oligocene-Early Miocene time. Instead, Puijila shows us how seals and sea lions took to the sea, evolving from otter-like forms that thrived on the Arctic coast, spreading south via more oceanic forms into the Pacific and Atlantic oceans, respectively.

This amazing find also answers another nagging question about pinniped evolution, do seals and sea lions form a polyphyletic, or artificial, grouping, much like the now defunct classification term "pachyderms". The evidence Puijila gives us emphatically says no to this idea. Recent molecular and DNA analysises have given weight to the theory that seals and other pinnipeds do form an actual taxonomic group, but there are still doubters. Scientists have been arguing for quite some time on these matters. While one group supports the idea that seals and sea lions form a natural group, descended from bears; the other side suggests that seals and sea lions evolved convergently, the former evolving from the otters and the latter evolving from the bears. This side cites the fact the fossil Potamotherium as evidence for this theory, saying that it is the real ancestor of true seals, as well as the fact that sea lions are mostly known from the Pacific Ocean, while true seals are mostly an Atlantic phenomenon. Potamotherium has been reclassified as a very otter-like seal, adding weight against the concept of pinniped polyphyly, but Puijila strikes the final blow. Its features suggest a common ancestry with seals and sea lions, showing that pinnipeds are indeed a monophyletic grouping.

Wallace, D. 2007. Neptune's Ark. University of California Press, California.

A Shameless Attempt At Advertising

Yes, this is an example of "doing exactly what it says on the tin". But this isn't for me, or Metazoica. In fact, its for a new exciting up-and-coming speculative evolution project that is due to hit the world full force in May. Zach Miller of When Pigs Fly and Will Baird of The Dragon's Tales are planning a new and exciting project; what might the world look like if the P-T extinction never happened. Now this is probably one of the hardest speculative evolution projects to do, the fauna and flora we have today is descended from the mere 10% of life that survived the end of the horrific P-T extinction, so one really has to bone up on their Permian knowledge before they take this project on (as in study the remaining 90%). Before the extinction, there were heavily armored pariasaurs, ferocious gorgonopsids, and numerous dicynodonts, just to name a few. No one has really attempted this project before, since it covers such huge spans of time and few have really taken the time to dig deep into the ecology of the Late Permian. But these two are trying, and from their results so far, it seems as thought they are doing excellent, and have this all planned out. So tune into When Pigs Fly and The Dragon's Tales in May to see more of this alt-Permian!

For those who cannot wait, Zach has a couple of short articles posted on his blog, here http://whenpigsfly-returns.blogspot.com/2009/04/further-studies-into-alt-permian.html concerning a derived gorgonopsid (barbouronopsid) and a small herbivorous archosaur, and here http://whenpigsfly-returns.blogspot.com/2009/03/proactive-dicynodonts.html about a species of aquatic dicynodont that takes the place of manatees and such, the walrodont.

Sunday, April 19, 2009

Family of the Week: The Gentle Sinecrus

This is the family Cervainiidae, and they are quite closely related to the tusked sinecrus, only these animals do not have tusks. They do however, live the lives similar to their tusked relatives and the modern manatees of today. These animals are generally larger than the tusked sinecrus. They are solitary animals that spend their entire lives in or near the water. They feed on the vegetation that grows in the water. Either aquatic plants, grasses, even algae. Sometimes they will even crawl out of the water to feed on the leaves of low-growing trees. Some species do this more than others though. The foreflippers are very long and powerful, and equipped with elephant-like fingernails. The tail is very long and propels the animal in an undulating fashion, much like whales. The eyes are relatively small, the mussle is short and blunt, but the mouth is rather flexible, almost like those of most land-based herbivores. The hind flippers are very small, and almost useless. In a small way though they do help the animal move over land and even anchors them in place to feed on trees. The neck is slightly longer than it is in the tusked sinecrus. There is no fur, but the soft flesh is quite colorful.

Like the tusked sinecrus, these animals are large and slender and inhabit lakes, ponds and rivers. Sometimes, they will even submerge in lagoons and even in the ocean. They do not go too far out into the ocean though. The largest of these sinecrus are in the genus Diplomala. They are mostly long in body and neck, and even have a slender beak-like muzzle. On land, they move much like the tusked sinecrus. They pull themselves along using their foreflippers and the feet and tail help out slightly as well. When feeding, these animals use their foreflippers and the mouth, which has flexible lips like manatees. These animals live in couples, rarely in herds. Couples may move overland together to get from one luscious patch of aquatic vegetation to another. They are slow reproducers, and only a single calf is born every 3 years. But these animals themselves can live up to 100 years, and reproduce right up to the end.

These animals have few predators. They may be taken by predatory bats, mongooses, foxes, predatory pentadactyls and Deinognathids. Most of their predators take these animals as they are crossing land from one body of water to another. With the exception of the deinognathids, most of their predators will not chase them into the water. Predatory bats may prey only on the youngsters, rarely taking adults unless they are weakened by sickness or something.

Saturday, April 18, 2009

Meet Labocania

In the spirit of my habit of bringing rare, obscure dinosaurs to your attention, I’d like to introduce you to Labocania anomala, a theropod dinosaur from the peninsula of Baja California. A well-kept secret of paleontology, Baja California is rich in fossils of the Late Cretaceous period, about 70 or so million years ago. Compared with “Alta California”, a slang name often given to our own state of California, Baja contains approximately twice as many Cretaceous dinosaurs in the northern half of the peninsula than the entire state does as a whole. In addition to Labocania, the peninsula has also revealed specimens of Lambeosaurus, Albertosaurus, and even specimens of strange polyglyphanodont lizards, strange iguana-like herbivores related to skinks.

But what kind of theropod is Labocania? That’s what makes Labocania so fascinating, the fact that we don’t know. Gregory S. Paul has suggested that Labocania was an allosaur, a Late Cretaceous specimen of a group that was supposed to have died out at the End-Turonian event, along with the stegosaurs, most pterosaurs, ichthyosaurs, and much of the other Mesozoic old guard. But, seeing as Gregory S. Paul is the same guy who tried to synonymize Deinonychus and Velociraptor, a very erroneous idea (and because of which we are stuck with giant, misnamed raptors prancing around the silver screen), I really wouldn’t put much stock on “the word of Paul”. In fact, if you asked me up until a couple of years ago, I would have probably said that Labocania was most likely a dryptosaur.

What are dryptosaurs? Dryptosaurs are a sort of catch-all term, referring to the more primitive tyrannosaurids, those with long, three-fingered arms like Eotyrannus, Dilong, and others. To be technical “dryptosaurid” really only refers to those dryptosaurs that belong to the family Dryptosauridae, a group of large primitive tyrannosauroids that rampaged across Eastern North America while their short-armed, bone-crushing kin did the same in the west, including such members as Dryptosaurus and Appalachiosaurus. It is not entirely outside the realm of plausibility that Labocania was a mainland example of the group as well. Similarities in the ischium between Labocania and other tyrannosauroids seems to support this theory. Holtz also seems to think this is the case, and described Labocania as a possible tyrannosauroid in his 2004 review of the group.

However, the idea that Labocania is a primitive, three-fingered tyrannosauroid might be seriously challenged in recent years, by an old face; the idea that Labocania is a type of allosaur. For a long time, the headstone of the allosaurs basically read: R.I.P. 90 MYA. But recently findings of new allosaurs in South America changed that. Meet Aerosteon, a fascinating animal for a multitude of reasons. First off its bones show that this animal had the same sort of advanced breathing system that we see in birds, which pushes back the evolution of full-blown bird lungs down several notches on the evolutionary family tree. Secondly, it was found in sediments dating to the Santonian age, 85 MYA…five million years after the allosaurs were supposed to have kicked the bucket. Further discoveries of unusual Cretaceous allosauroids (namely Australovenator) have allowed us to identify several other species, which previously were scattered around in different groups and their relationships unknown, as belonging to the same group, the Neovenatoridae. This includes the mysterious genus Megaraptor, as well as the dinosaur Orkoraptor, previously thought to be a coelurosaur. Orkoraptor is interesting because it lived at the very end of the Mesozoic, in the Maastrictian period of the Late Cretaceous. Since we have evidence of some dinosaurs making the trip from South America to North America (Alamosaurus and possibly the alvarezsaurids), who’s to say that allosaurs could not have made the same journey.

So what is Labocania? The point is, plain and simple is that we don’t know. The material we have already is too fragmentary to make any judgments one way or the other. Unfortunately, between political strife within Mexico and arguments of bureaucracy between Mexico and other countries, it doesn’t look like there will be any new expeditions to Baja California anytime soon. But to end this tale on a bright note, Mexico is increasingly taking its place in the world of paleontology, and this country, oftentimes passed over in paleontological studies, is starting to gain attention through new discoveries in the Cohuila province (Velafrons and some other new dinosaurs that I’m really not supposed to talk about). So perhaps one day we will get a perfectly preserved skeleton of Labocania, someday…

Predatory Dinosaurs of the World by Gregory S. Paul
Dinosaurs and Other Mesozoic Reptiles of California by Richard P. Hilton

Monday, April 13, 2009

The Success of the Primates

Many speculative evolutionary scenarios have primates going extinct. However, as we shall see, primates are actually very adaptable and successful creatures, and will very likely survive into the future.

The first primate, Purgatorius, appeared in the Late Cretaceous or Early Paleocene of North America. If one were to look at this animal, the idea that these animals led to monkeys, or even us, would not come to mind. This animals was about the size of a possum, and if one could not tell that this animal gave live birth, one might mistake it for an odd possum as well.

The actual age of Purgatorius is in debate. Some fossils of Purgatorius seem to suggest that it was present in the Late Cretaceous, while other scientists seem to suggest that Purgatorius is earliest Paleocene in age, and the Cretaceous fossils in question were washed out of their original burial position and reburied in Cretaceous strata. However, if the former idea is true, then the primates would have been around during the Cretaceous…and survived the infamous bolide impact that killed off the dinosaurs. Even if Purgatorius is not Cretaceous in age, genetic studies have shown that the earliest primates probably originated somewhere in the later Cretaceous, and even barring that the primates more archaic relatives, the tree shrews, probably evolved during the Cretaceous.

Tree shrews are also around today. Like mentioned above, they are not related to shrews as all, but would be better classified as primitive primates. But the treeshrews are actually classified in their own group, Scandentia, in the grand scheme of mammalian classification. Many species of Scandentia today are considered low-risk, and are rather likely to survive into the future.

Primates themselves have also proven to be adaptable and widespread. Primates are actually rather generalized mammals, retaining five digits on each limb, a full set of teeth (in comparison to other mammals, such as felids and bovids, who have lost many of their molars, canines, and incisors). They have survived for quite some time as well.

Primates have had two great radiations, one of the non-simiomorph primates (lemurs and tarsiers), which include the lemurs as well as extinct groups such as adapids and omomyids. However, due to the Eocene drying, primates began to become restricted in their range. Once found on North America, Asia, Africa, and Europe, primates became restricted to Africa. However, once there, primates adapted, and thrived. Then came the radiation of the “advanced primates” the simiomorph primates, which include all of the monkeys and apes of the world today. In addition to the various species of arboreal African monkeys, this radiation also resulted in the South American monkeys, the platyrhines; the baboons, and the lineage that led to our family, the great apes and hominids.

While several lineages of primates, such as the modern apes such as gibbons, chimpanzees, gorillas, and orangutans are critically endangered, and their chances for surviving into the future seem rather dim, many of the other primates appear to be doing okay. There are over 350 species of primates, making it the fourth largest order of mammals outside of bats, rodents, and the shrews. Many of these are very likely to survive, and are not endangered at all. While they may not deviate further from their arboreal lifestyle, primates are very likely to survive into the future.

Wednesday, April 8, 2009

This Ends Now...

As a mammal paleontology enthusiast, I have come across numerous reconstructions of prehistoric mammals. However, one particular group is always reconstructed the same way. The ground sloths are always portrayed as omnivorous opportunists, feeding on leaves and plant matter, but also eating meat and carrion as well.

The entire idea that ground sloths could have eaten meat comes from a single paper entitled “Megatherium, the stabber”. In it, the scientists suggest that Megatherium and its ground sloth kin were carnivorous superpredators, on the sole basis that the muscles of Megatherium were strongly anchored, and could thus move fast.

This claim is rather dumb. While being able to move an react fast does mean Megatherium was bad-ass, it doesn’t make it a carnivore. We know that ground sloths were more energetic than their slow, tree-climbing kin today, so it makes sense that they could react and move faster. In short, if you tick a Megatherium or an Eremotherium off, it will take your head off in a second. By the same idea that is claimed here, because pronghorn can run very fast, they must chase down prey. Or, because peccaries have big, nasty teeth, they use them to hunt and kill other animals.

Enter exhibit two, the teeth. The teeth of ground sloths are dull, flat, and horribly unsuited for meat consumption. Most carnivorous or omnivorous animals have somewhat pointed teeth, for tearing off consumable chunks of flesh. But ground sloths don’t have even the closest semblance to these, and their teeth actually resemble dull molars more than ripping canines and incisors.

Still aren’t convinced? Well, here’s the final nail in the coffin. In the deserts of the Southwest United States, desiccated sloth dung has been found; specifically from the genus Nothrotheriops, a close cousin to Megatherium and Eremotherium. This dung is not fossilized, just dried out, and scientists have analyzed it to find out what sloths ate. The dung had no animal matter in it, just vegetation; mostly made up of the globemallow tree.

In short, the idea that Megatherium was a giant glyptodont killer or a scavenger as suggested in the paper is completely bogus. It is little more than a claim based on “The Rule of Cool” (http://tvtropes.org/pmwiki/pmwiki.php/Main/RuleOfCool). Scientific evidence has shown us that ground sloths were large herbivores, and although badass, were not likely to eat your remains after they beat you to a bloody pulp.

Tuesday, April 7, 2009

Family of the Week: The Tusked Sinecrus

This is a small family of animals that are derived from elephant shrews. They somewhat resemble the modern manatees, and are found only in what is today the Hawaiian Islands. They are rather more slenderly built than manatees, and have a long tail and small hind flippers. The front flippers are large and strong and tipped with short, flat fingernails. They are very flexible and used for grasping the aquatic plants and grasses that these animals feed on. The body is long and barrel-shaped, the head is short and blunt, the canine teeth have become tusks that grow outward rather than up or downward. There is no fur, but the flesh can be very brilliantly colored, especially in the males. The tail is like those of whales, only somewhat longer. They propel themselves through the water with an undulating motion of their tail. They are considerably faster and more high-energy swimmers than manatees. Like manatees though, they inhabit lakes and ponds. The forelimbs are powerful enough that these animals can actually move from one body of water to another. They pull themselves on land in the same manner as the mud-skippers (Gobiidae, Oxudercinae) of the Cenozoic. They have no layers of blubber, as in whales, so they will not crush themselves under their own weight. They can actually stay on land for several hours before needing to retreat back into water.

Most species have about 2 tusks that protrude out the mouth. However, Cornurostris has only one tusk. These tusks are most often used for sparring among males, and the males indeed have the largest tusks. The tusks play no part in feeding. The only species that has the smallest tusks are in Egeodonta. In this species, the tusks never extend out of the mouth. All these species are basically large and slender, the largest among them is about 11 feet long. These are in the genus Bidens. However, they are still very capable of walking along the land when necessary. But they are not blubbery like whales or dolphins. This allows these animals to easily move on land for considerable distances.

The only time these sinecrus come to land is to relocate or mate. The females usually birth their calves in the water, away from any land-based predators. They only give birth to a single offspring, and the baby is born tail first, as in whales. The mother then nurses the baby. She floats to the water’s surface, still safe away from land-based predators, and exposes her belly, where the nipples are, and the baby eats that way. The mother’s nipples are fixed so that she herself pumps the milk out so the baby doesn’t have to suction the milk out it’s self. But this way the baby can eat and breathe at the same time and so can the mother. Often, she will even use her foreflippers to hold the baby to where the nipple is. The baby is well protected, though the males play no part in the family role, the mother is perfectly capable of defending her baby by using her sharp tusks as a defense against predators.

The islands where these animals live is not exactly teaming with predators. Among the worst predators are the smaller carnivorous sinecrus of the family Ephodozoidae. These are the worst because they can, and usually do, attack the tusked sinecrus and their young right in the water. Predatory bats like Cercomoloch may take the young from the air, as the mother is nursing them. Sometimes, adults may also fall prey to these pteropods as they are crossing the forest floor to move from one pond to another. Cercomoloch can easily kill even an 11-foot long adult with their powerful talons. Another predatory candidate would be the predatory rats that inhabit these islands. They may take down the tusked sinecrus as well as they try to cross the forest floor. But these animals are not completely without defenses. They can use their tusks easily to ward off any predatory attacks. The tusks are sharp and powerful and can quite simply act like the blade of a swiss army knife, and slice open a predator. Or a well-placed stab can immobilize and even kill a predator.

Saturday, April 4, 2009

Parallel Evolution

So what is parallel evolution? What are some good examples? Well, parallel evolution is when different species are alike in either physical features or natural habits. Modern examples of parallel evolution are how tree shrews are like a lot of modern lower primates. Both families live in trees, have opposable fingers and toes, and tree shrews even closely resemble the earliest primate families. However, they are not really related. Though that is still a subject of some debate. Or like the similarities between beavers and otters. Both are adapted for an almost fully aquatic lifestyle. But they are in no way related. The list of parallel evolution just goes on and on.

I was looking at some of my own animals of the future and noticed I took advantage of this theory quite a bit! For example, the similarities between the family Promonsamiidae and the species Oreolemur. Both are pentadactyls of the Metazoic that take to the water, instead of the trees. They resemble each other in a lot of ways. They are all otter-like lemurs and have flat tails and webbed feet. Though their timelines don't collide, so they don't compete with each other. Though they are both lemurs with many similarities, they are in no ways related. They are separated by about 30 million years of evolution. By the time Oreolemur comes around (about 70-100 million years AM), the Promonsamiidae have already become the family Delphinadapidae. Oreolemur is in a family of lemurs that are all primarily tree-dwellers, like Leptonosoma and Mesocheirus, and actually evolved from a small, cat-like, river-dwelling lemur called Potamailuria. This lemur is a weaker swimmer than Oreolemur, but powerful enough to battle tough currents, crawling along the river floor in search of fish and mollusks.

Then there is the Delphinadapids. They come along during a time when a larger, more well-established predator rules the oceans. This predator is Thalassogenetta. It is the largest of all Viverrids, but they resemble the Delphinadapids in many ways. The tail is made to move in a very eel-like fashion. The main difference is Thalassogenetta has the cat-like retractable claws, and they use them to grasp their prey, even in the ocean. The tail is used to propel them, and the foreflippers are used for steering. Thalassogenetta feeds on anything. Their primary prey is the giant sea turtles in their range. But they do not stop there. They also feed on fish, giant squid, and sea mammals, including the Delphinadapids and Oreolemur. Though Thalassogenetta taking Oreolemur is somewhat rare, as they prefer to prey on larger animals. But this is a great example on how I capitalized on parallel evolution in my animals of the future. And this isn't all, there are several examples of this phenomenon throughout my site.

Many of the animals on my site would even be considered to have evolved parallel to modern animals. Such as the similarity between lemurs like Leptonosoma and the modern sifakas. Both have disproportionately long legs for easily moving through the trees, long tails, and short forearms. But there are some differences as well. Leptonosoma is more slenderly built than the sifakas. This and several other adaptations to their skeletal structure make them much more phenominal leapers than sifakas. They also have larger ears that they can move independently, and they have a more mixed diet. Also, I have the Metazoic versions of camels, apes and hyenas. None are related to the families we have today, but they evolved parallel to the lifestyle of these animals, and when you look at them and their lifestyles in the Metazoic, it's hard to tell the difference between them and their modern counterparts.

Friday, April 3, 2009


Don't mind me, I'm doing a test. For some reason, the comment option was eliminated from the last post and I don't know why.

Thursday, April 2, 2009

What's He Going To Do, Nibble Your Bum?

I re-watched my old copy of Monty Python and the Holy Grail recently, and it got me thinking, specifically about this scene here...

My question is, if the world actually does go nutters and a rabbit does develop carnivory, what exactly would it look and act like? Its not exactly as far-fetched as it seems, rabbit mothers do eat their own young on occasion to hide the smell of a dead baby, though it is highly unlikely. So for the sake of discussion lets look at the biology of Carnilagus montypythonorum

The first think one has to ask about this rabbit is the teeth. Lagomorphs, like their cousins the rodents, have large, evergrowing teeth, which allow them to tear through tough plant matter. However, unlike rodents, rabbits also have a second, smaller pair of incisors in the front of the mouth, which help to reinforce the first pair. The first pair of incisors will become our killing tools for the rabbit. The incisors will become hypertrophied, forming long, spear-like fangs.

But what of the other four incisors? What becomes of them? Well, these teeth become sharp too, though not the saber-like killing tools of the first pair. Instead, these teeth move, the upper pair of incisors stay where they are, and the rear pair move out to the sides of the main two. What's the point of this? Well, quite simply, these rear incisors keep the front pair sharp. To make sure the rabbit is able to kill at any time, the rear pair of incisors grind against the front pair. When the upper pair grow too long, they break off from the pressure given to them by the upper pair, thus keeping them sharp.

As for the rest of the teeth, the only thing I can think of is that the first two pairs of molars change. The first premolar becomes buzzsaw-like and sharp, much like the premolars of the carnivorous macropod Propleopus. The tooth behind it becomes the carnassial, working to shear off flesh from the carcass of the dead. The skull of Carnilagus has some differences from that of its kin. The most noticable is that the condyles have shifted back, and a saggital crest has developed. This gives the rabbit a more powerful bite needed to take down prey.

As for the external appearance of the rabbit, it has a few extra tricks up its sleeve. Its eyes have become larger and...may I say....cuter, in order to take in more light to hunt in lower light conditions, such as at dusk. Its fur is covered in a sort of oil that keeps blood and pieces of flesh from sticking to it, and keeps its fur white and looking clean.

So how exactly does Carnilagus live? My guess would be that due to its small size, the majority of Carnilagus' diet is made up of small animals; rodents and birds. However, its ferocious weaponry "with big nasty teeth" means that if threatened, it can take on foes even multiple times its size, including blundering knights.

...unfortunately, all of these wonderous adaptations do little in the face of The Holy Hand Grenade.

You've Been Punked

As many of you may have guessed, yesterday's post was a humorous prank, for April Fools Day. I wanted to just mention a disclaimer that there is no feathered crurotarsian named Agriosuchoides inexpectatus. In fact, that's why I called it Agriosuchoides instead of Agriosuchus, so as not to make a cool name a nomen dubium. I hope you all enjoyed my little joke as much as I did, and be sure to keep tuning into Metazoica.

Wednesday, April 1, 2009

Feathered Crocs?!

Hot on the heels of the recently discovered feathered ornithiscian Tienyulong confucusi from China is another amazing discovery, one that shakes up our idea of archosaurs as we know them. For years now, the Fergana region of Kyrgyzstan has been known to produce amazingly preserved fossils, mostly insects and invertebrates, but occasionally strange and unusual vertebrates, such as the enigmatic Sharovipteryx and Longisquama.

Well, today, another strange critter made that list. Meet Agriosuchoides inexpectatus, a crurotarsian archosaur from the Late Triassic (Ladinian/Carnian time) of Kyrgystan. This find is important enough by itself, the anatomy of Agriosuchoides appears to suggest that it is the most primitive crocodylomorph ever found, possible related to the sphenosuchians or other primitive, gracile crocodiles. But that is not even the most exciting part. The most exciting part of all is that the fossil appears to be preserved with what appear to be protofeathers around the shoulders, neck, and head!

This has amazing implications. If Agriosuchoides is real, this would mean that feathers or protofeathers are not just found in ornithodirans, as the current fossils of pterosaurs, Tienyulong, Psittacosaurus, and theropods suggest, but that they were present on all archosaurs. The modern day crurotarsians, the semi-aquatic crocodiles, probably lost their feathers secondarily to retain heat better in water, just like whales have today.

Once we get past the feathers, Agriosuchoides appears to be a normal, if somewhat primitive crurotarsian. Some have suggested that Agriosuchoides is not actually a crocodylomorph, but instead a much more primitive crurotarsian archosaur, one that evolved a sphenosuchian-like body shape through convergent evolution. But none doubt that it is a crurotarsian; the distinctive crurotarsian ankle makes that point very clear.

So what does this mean for paleontology? Well, for one it could suggest that all of those Triassic archosaurs we see could be fluffy. Rauisuchians, aetosaurs, probably not phytosaurs, but they all could be fuzzy to an extent. It also raised the question "how basal are feathers". The feathers of Agriosuchoides are more primitive than those found in pterosaurs and dinosaurs; slightly more scale-like than "dino-fuzz", but it still doesn't answer our question as to how early did feathers evolve. More fossils will be needed for the answer.