Chiidax the Northern Fur Seal and the Evolution of the Otariids

Late last year, the New England Aquarium in Boston, Massachusetts received Chiidax, an orphaned northern fur seal (Callorhinus ursinus).  However, it was last July that Alaska SeaLife Center first took in Chiidax, after he was left outside the Alaska Department of Fish and Game offices.  A note which was included on the outside of the box that the pup came in said that the pup's mother had died while she was giving birth.  Notice how in the first two pictures of Chiidax below, the pup is covered in an all black coat, a mark of his young age.

After the pups are weaned at around four months old, they molt into their next coat, the cream and brown color of the young juvenile northern fur seal.  Look for those in these next four pictures, taken sometime last fall.  The post on ZooBorns (read that HERE) doesn't say exactly when the pictures were taken, but given that the post was published late last November, these last photos were presumably taken around then.  

When the first post on Chiidax was written on November 23rd of 2013, he weighed 18 pounds, but when he's full grown, he will definitely be a bit bigger: the males, or bulls, of the species can weigh nearly 600 pounds, which is several times more than the females weigh!  The males have to be so large because they create harems of thirty to forty females, and defend them from other males.  The seals are native to the Pacific Coast of the United States, as well as the coast of the Bering Sea in Canada, Alaska, and Russia.  

The last report on Chiidax was in late December, on the 29th.  Below are several pictures that were shared then.  You can see how smooth he looks, and how perfectly adapted for a life beneath the waves this creature is!  

The northern fur seal is the sole extant member of the genus Callorhinus, but there is also a fossil species of Callorhinus.  C. gilmorei is known from the Pliocene Epoch of southern California and Mexico, as you can see in this paper HERE.  Other sources cite another paper, linked HERE, as stating that this genus is also known from Japan, but I was unwilling to pay the fee to read the paper, so that fact remains unconfirmed.  If you have a subscription to this online journal, let me know what you find!

According to the first paper, the eared seals, or the members of the family Otariidae, can be traced back at least to the Mid to Late Miocene Epoch, approximately 11-12 MYA in California, in the form of Pithanotaria starri.  Another taxon, Thalassoleon mexicanus, is known from Mexico during the Late Miocene, approximately 5-8 MYA.  The authors of the paper suggest that between 5 MYA and today, between our time and the time of Thalassoleon, was when fur seal diversification took off, resulting in the eight extant species of Arctocephalus and the extant Callorhinus ursinus, which includes little Chiidax!  The genus Arctocephalus, along with the genus Callorhinus, comprise the extant members of the eared fur seals.  The writers of the paper also suspect that it is during this 5 million year period that the sea lions developed as well.

Things have probably changed a lot in this area of paleontology since this paper was published in 1986, but unfortunately I can't seem to access most of these papers.  Callorhinus gilmorei still seems to be a valid taxon, however, as do Thalassoleon and Pithanotaria.  Hopefully, new fossils will yield more interesting results regarding these creatures very soon!  

Unless otherwise noted, the photo credit for all of these pictures in the post go to ZooBorns, either this post HERE or HERE.  

Boston on Dwellable

Works Cited:

Top Ten Mammals That Look Like Something They Aren't (Part 2)

Here is Part 2 of this duo of posts.  For Part 1, click HERE.  What are these two posts about?  Well, we are going to be taking a "Top Ten" look at some mammals that look a lot like something they aren't.  Sometimes, these two animals are fairly closely related: other times, they are quite far apart!  All of these examples will be results of a fascinating phenomenon known as "Convergent Evolution," which is where similar ecological and environmental factors cause two very different animals to evolve in a similar fashion.  So let's dive right in!  But first, this is the birthday post of Joseph Kleinkopf, happy birthday Joseph!

5.  Civets and genets - These two groups of animals are quite possibly some of the most unknown animals that are around today.  Members of the family Viverridae in the order Carnivora, if someone does in fact see one, they usually just assume that they are cats, dogs, or something else along those lines.  The family that the viverrids are most closely related to are, in fact, the cats, but they are also related to they hyenas and the mongooses.

4.  Maned Wolf - The maned wolf is neither a wolf, as its name implies, or a fox, as its outward appearance would indicate.  It is related to both, and is in the family Canidae (the dog family) just like wolves and foxes, but it is thought to be most closely related to the South American bush dog.  Interestingly, although small vertebrate prey is quite important to the maned wolf, it eats a great deal of fruits and vegetables, with the most frequently consumed fruit called the wolf apple.

A slightly fuzzy picture of a brown-morph black bear right outside of our tent-cabin in Yosemite!  Photo Credit: Julie Neher

3.  Black Bear - When it comes to the names of the three bears that inhabit North America, they can be very misleading indeed.  ESPECIALLY the black bear, for the black bear, like many other animals throughout the world (including, of course, humans), has different color morphs.  The black bear is, of course, most frequently black.  However, some of the time, the black bear is actually brown, or cinnamon colored, which is not to be confused with the ACTUAL brown bear (or grizzly bear).  In Alaska and northwest Canada, there is the "glacier" color morph, a grey-blue phase.  But I think my favorite is the "Kermode" color phase, which is exclusive to the coast of British Columbia.  This bear is a creamy-white color, and looks a heck of a lot like the polar bear!  How very, very confusing!

2.  Thylacosmilus - Over the course of mammalian evolution, the marsupials have spat out a large number of look-alikes, or animals that evolved via convergent evolution to appear a great deal like other animals throughout the world.  One of the most amazing of all of these (by far, in my opinion) is Thylacosmilus, a marsupial carnivore from the Miocene and Pliocene Epochs of South America.  Thylacosmilus convergently evolved to resemble the saber-toothed cats of North America.  Unfortunately, following the creation of the Isthmus of Panama that connected North and South America around 2 MYA, the saber-toothed cats like Smilodon moved down the newly-formed land bridge to colonize South America during the Great American Interchange, outcompeting Thylacosmilus in the process.

1.  Raccoon Dog - The raccoon dog is a fantastic case of an animal that is now that it appears to be.  You take one look at it, and you decide conclusively that you are looking at a raccoon, no doubt about it.  Your second and third takes yield the same result.  However, the raccoon dog is not a raccoon, as both its name and appearance might indicate: its a canid, through and through!  Listed as "Least Concern" by the IUCN, the raccoon dog is native to eastern Asia, and is not very closely related to any extant species of dog.  Just a tip, if you are trying to make someone look foolish, showing them a picture of a raccoon dog and having them guess what animal it is is an excellent way to show off your animal-prowess.  Unless they know what it is, in which case you will be the more foolish.

Thanks for joining us tonight for our top ten list!  And remember, if you have a birthday coming up, just email me the date at cuyvaldar123946@gmail.com with the date and your favorite animal, and I will do my best to get a post in! 

Top Ten Mammals That Look Like Something They Aren't (Part 1)

Today, we are going to be taking a "Top Ten" look at some mammals that look a lot like something they aren't.  Sometimes, these two animals are fairly closely related: other times, they are quite far apart!  All of these examples will be results of a fascinating phenomenon known as "Convergent Evolution," which is where similar ecological and environmental factors cause two very different animals to evolve in a similar fashion.  So let's dive right in!  But first, this is the birthday post of Joseph Kleinkopf, happy birthday Joseph! (For Part 2, animals 5-1 of the countdown, click HERE.)

10.  Bear Dogs - As their name implies, the bear-dogs are a group of mammalian carnivores that greatly resemble both bears and dogs.  However, they are neither!  According to The Big Cats and their Fossil Relatives by Alan Turner, they are thought to be fairly closely related to dogs, and more distantly related to bears.  Their remains are most commonly found in North America, although they are also found in Europe, Asia, and Africa.  Temporally, these animals lived during the Miocene Epoch, and are though to have arisen about 15 MYA, and fallen into extinction around 12 million years ago (MYA).

9.  Entelodonts - The Entelodonts, frequently referred to as "Hell" or "Terminator Pigs" greatly resemble the extant (still around, opposite of extinct) pigs and peccaries.  However, they are in a separate family from both the pigs and the peccaries, the family Entelodontidae, but all three do reside in the order Artiodactyla.  Some paleontologists believe that these guys are more closely related to whales and their relatives than pigs, but their exact phylogenetic relationship is unclear.  They inhabited North America and Europe during the Oligocene Epoch, around 34-32 MYA. 

8.  Hyrax - This little guy looks like he would be a rodent, but his true relatives are actually much more surprising!  Weighing between about 5 and 10 pounds, the hyraxes are actually fairly closely related to the members of the family Proboscidea, or the elephants and their relatives!  The extant hyraxes have their own family, Hyracoidea, but their ancient ancestors are thought to have branched into the extant hyraxes, the elephants and kin, and most likely the manatee and its relatives!  Hyraxes are found exclusively in Africa and the Middle East.

7.  Red Panda - The red panda has a long history of uncertainty in regards to its phylogenetic relationship to other animals, as has its namesake, the giant panda.  However, now we know that the giant panda is in the family Ursidae, or the bear family, and the red panda is now classified in its own family, Ailuridae, closely related to the mustelids, raccoons, and more, distantly bears.  For more information about the red panda, click HERE.  For more information about the giant panda, click HERE.

6.  Rabbits and Pikas - Even up until just a few years ago, I had assumed that the rabbits and the pikas were both rodents.  They look a lot like them, and they share the trait of continually growing teeth.  However, the members of the order Lagomorpha, which is the order that includes the rabbits and the pikas, differs from the order Rodentia in that they possess four incisors, as opposed to two for the rodents.  Furthermore, most rodents are omnivorous, while the lagomorphs are almost entirely strictly herbivorous.

For Part 2, animals 5-1 of the countdown, click HERE.

And remember, if you have a birthday coming up, just email me the date at cuyvaldar123946@gmail.com with the date and your favorite animal, and I will do my best to get a post in! 

The Denver Gem and Mineral Show Part 2: The Piscivores (Excepting Penguins)

As we started talking about a few weeks ago, my friend Masaki Kleinkopf and I were able to visit the Denver Gem and Mineral Show at the Denver Merchandise Mart.  Last time, we talked about the giant ammonites, the baby eryops that Dr. Robert Bakker was working on, the gliding Indonesian lizards of the genus Draco and the pterosaurs that evolved from creatures purportedly much like this millions of years ago.  Today, we are going to talk about all of the piscivorous animals that we saw there, except for the fossil penguin that I saw there.  Knowing me, that would easily take up one whole post of its own there.  Keep in mind throughout this post that I'm not certain for all of these animals that they actually eat fish, I just know that the large groups that they belong to often eat fish.  Today, we are going to be looking at the mosasaurs, crocodilians, pterosaurs, sea lions, other fish, sharks, and the dreaded piscivorous dinosaur Spinosaurus.  

MESSAGE FROM ZACK FROM THE FUTURE:  Hello, everyone.  This is Zack Neher.  I have travelled to this post from the future.  I wanted to give you a link to the Homebase for these posts.  I am like Rose Tyler, leaving clues in the form of Bad Wolf.  Except this is not quite like that at all really.  Anyways.  The Homebase for the series is HERE.

Myself next to a gigantic mosasaur skull

I am pretty sure that this is the skull of a mosasaur , anyway.....it looks more like a mosasaur skull than the skull of a crocodilian, if you ask me

A mosasaur jaw, from Morocco by the looks of it

A mosasaur skull (Platecarpus, if memory serves, but it is entirely possible that I am wildly off) in front of a fossil ray

Another huge mosasaur skull

We also got to see the teeth of a piscivorous pterosaur.  The teeth of a piscivore are usually different from those of other carnivorous animals due to their conical shape.  The teeth of the fish eaters, like those of crocodilians and dolphins, are usually conical in shape, to prevent prey from struggling out of their grasp.

The teeth of a piscivorous pterosaurs

Below are the skulls of various crocodilians.

 

 

The skulls of these dudes seem like they should be out of a cartoon or something, they are so weird and comic looking!

Here are a pair of photos of fossilized sea lion teeth, both from the extinct sea lion Imagotaria sp., from the Miocene to Pliocene in the Atacama region of Chile.

Imagotaria sp., from the Miocene to Pliocene in the Atacama region of Chile

Imagotaria sp., from the Miocene to Pliocene in the Atacama region of Chile

Next, a picture of a pair of fossil jellyfish!

Fossil jellyfish!

Next are the teeth of the gigantic, fifty to sixty foot long carnivorous (or actually, piscivorous) dinosaur: Spinosaurus.  Also in the picture are the teeth of another enormous carnivorous dinosaur that lived in the same area of Northern Africa as Spinosaurus at this time of the Cretaceous Period: Carcharodontosaurus, who was not a piscivore, at least not primarily a piscivore, like a penguin, or as Spinosaurus is purported to
be.  (Did you see that alliteration?  My language arts teacher would be most impressed).  I discuss both Spinosaurus and Carcharodontosaurus in two previous posts, which you can look at HERE FOR SPINOSAURUS and HERE FOR SPINOSAURUS AND CARCHARODONTOSAURUS.

The teeth of Spinosaurus.  Actually in this shot, it looks as if most or all of these teeth belong to Spinosaurus.

And now for some pictures of the teeth of Megalodon, the largest shark that is ever known to have lived!  I have talked about Megalodon in the past, click HERE to learn more.

 

Now for some random ones.

It's a fish eat fish world out there

A pair of shark jaws.  I am not certain as I don't remember at all and they are unlabeled, but I believe them to be jaws of sand tiger sharks.  Again, I could be totally off on this!

Top Ten: Extinct Sea Monsters (Part 1 of 5)

Since ya'll kinda get gypped on Wednesdays with the "What Is It?" challenge, I decided that, when I do do the challenge, I will also include a "Top Ten" list.  I mean, come on now, who doesn't like lists?  I know some of my friends would be absolutely and completely lost without them!  So for today's "Top Ten," we are going to take a look at some of the world's most amazing, extinct sea monsters.  This is also up for debate, so if you disagree, just give me a holler!  Also, they are not in any particular order, I just kind of threw them all in there!  So without further ado, here we go, with our "Top Ten:  Extinct Sea Monsters!"

1.  Megalodon - This gigantic relative of the extant great white shark was thought to be simply massive: perhaps even sixty feet in length!  Living the world over, Megalodon stalked the seas during the Miocene and Pliocene Epochs, and only died out during the current Pleistocene Epoch, around two million years ago.  It is thought that Megalodon evolved to such gigantic proportions in order to be able to attack the massive whales that had started to evolve in the cooler seas of the Miocene and Pliocene.  Remember now: if it's a shark, then it's a fish!

A tooth fragment from Megalodon at this excellent restaurant called The Crab Shack on Tybee Island off of the coast of Savannah, Georgia. 

2.  Basilosaurus - A massive, predatory whale (and, therefore, a mammal) that cruised the seas in the Late Eocene Epoch, 40 to 34 MYA, fossil discoveries of this massive animal were reportedly so common in the southern United States during the early 19th century, that bones of Basilosaurus would be used as furniture!  It was first discovered in Louisiana, and is the state fossil of both Mississippi and Alabama.  Basilosaurus has also been found in Egypt and Pakistan.  At around sixty feet in length, the same estimated length of Megalodon, Basilosaurus is thought to have been the biggest creature alive at the time.

COMING UP:

3.  Liopleurodon
4.  Shonisaurus
5. Elasmosaurus
6.  Dunkleosteus
7.  Archelon
8.  Leedsichthys
9.  Tanystropheus
10. Tylosaurus

This post is part of the "Top Ten: Extinct Sea Monsters" series.  For the rest of the posts in this series, click HERE. 

Smilodon Vs. Thylacosmilus: The Saber-Toothed Marsupial

Two million years ago, a saber-toothed predator stalked the landscape of South America.  Possessed with long, dagger-like teeth, Thylacosmilus was undoubtedly a terrifying predator of the plains of Patagonia.  This saber-toothed predator would have given even the saber-toothed cats pause, despite the fact that (to paraphrase Obi-Wan Kenobi), "He's more kangaroo now than cat."  Despite superficial similarities, Thylacosmilus was not a saber-toothed cat.  Instead, it was a six foot long, 500 pound saber-toothed marsupial.

A reconstruction of Thylacosmilus by the talented young artist Sam Lippincott.  Interestingly, the super-sized canines of Thylacosmilus grew continually throughout its life, unlike those of Smilodon or Xenosmilus (see below), two of the actual saber-toothed cats.  Photo Credit: Sam Lippincott

The immense canines possessed by Thylacosmilus had previously evolved in both the cat-like Nimravids and the various saber-toothed cats (amongst others), and is a classic example of convergent evolution, a topic, in my opinion, that is one of the most interesting happenstances in nature.  We will hopefully talk about convergent evolution sometime next week.

A mounted skeleton of Xenosmilus, a type of saber-toothed feline, at the Mace Brown Museum of Natural History at the College of Charleston in South Carolina.  I got to visit here in July of 2014, and it was a very nice little museum.  Compare the skull of Xenosmilus with that of Thylacosmilus (below).

Anyways, Thylacosmilus lived during the Miocene and the Pliocene Epochs, from 10-2 MYA.  Up until 2 MYA, South America had been its own, separate land mass, not connected to any other continents since some time during the Cretaceous.  2 MYA, however, something extraordinary happened: the Isthmus of Panama was formed, connecting the two continents.  With this connection, came something scientists have dubbed the "Great American Interchange."  Animals from both continents could move, and spread out into the other continents.  For some creatures, like the saber-toothed cats, this was a good thing; they moved down into South America from North America and dominated the landscape.  For other predators, like the terror-bird Titanis(again, a topic for another time), it was good, for a while; after moving into the southern part of North America, however, Titanis was outcompeted by other predators.  For Thylacosmilus, it was down-right disastrous.  Shortly after the Great American Interchange, fossil evidence of Thylacosmilus entirely disappears, similar to the competition between the dingo and the thylacine that drove the thylacine to extinction on mainland Australia.

The skull of Thylacosmilus on display at the American Museum of Natural History in New York.  Got to see this sucker in person in August 2014, when I visited with my good buddy Zach Evens! 

This is a partial post for the "Convergent Evolution" series.  That means that this post is partially included, but was not made specifically to be a part of that series.  HERE is a link to the Homebase for this series.