Prehistoric fauna

[Serjeant Grumbles]

Because it is an intriguing topic, I thought I'd make a thread dedicated to creatures long extinct. Life really began to diversify in the Cambrian period (542-488 million years ago), with what is known as the Cambrian Explosion. Much like the early episodes of a long-running series often seem a bit strange in retrospect, so it is with some of the bizarre creatures of this time period:

Hallucigenia

Opabinia, of the extinct taxon Dinocaridida, believed to be a stem group of arthropods.

Anomalocaris - another dinocarid, although it was only about one meter long max, it was a monster for its time, and an apex predator.

Nectocaris, tentatively classified as a cephalopod, but some say it's an arthropod.

Pikaia, a chordate of the cephalochordate subphylum, and a likely ancestor of vertebrates.

 

[Saparmurat_Niyazov]

This list isn't limited to that time period, but it's pretty interesting. The Quetzalcoatlus is amazing.

http://www.toptenz.net/top-10-prehistoric-animals.php

 

[damnromulans]

I like Pleistocene era mammals the best, especially elephant ancestors.

 

[Vimana]

Mastodons and mammoths were different genuses, and also smaller than modern elephants. I was pretty disappointed when I found out.

 

[Serjeant Grumbles]

Well, that depends on the species of mammoth. The largest, the Songhua River mammoth, was the second largest land mammal to ever live, after Indricotherium (aka Paraceratherium/Baluchitherium).

But as I'm generally working in chronological order, here is some more early marine life:

Cameroceras, a genus of Nautiloid - Ordovician period (~488-444 mya)

Orthoceras, another Nautiloid, albeit a lot smaller at 15cm, also had its heyday in the Ordovician, but the genus survived all the way until the Triassic period.

Some typical Ordovician life forms.








Some organisms of the order Euryptida (sea scorpions):

Eurypterus, averaging about 5-9 in long, but the largest individual found was 1.3m (4.3 ft) long, of the Silurian period (432-418 mya)

Pterygotus, the second largest known eurypterid, up to 2.3 meters long, Silurian-Devonian.

Jaekelopterus rhenaniae, the largest known eurypterid (2.5 meters), middle Devonian period (~390 mya)

 

[Serjeant Grumbles]

Here are some Paleozoic fish. There is no one class of "fish," rather, there are multiple classes, some extinct, some still extant.

Ostracoderms, jawless armoured fish, originated in the Ordovician period but were extinct at the end of the Devonian period.

Several Cephalaspis species, clockwise from right: C. magnificans, C. poweriei, C. lyelli, C. whitei, early Devonian. (415-398 mya) They were anywhere from goldfish-sized to trout-sized.

Pteraspis, about 8 inches (20cm) long, early Devonian.





Acanthodii were the first vertebrates with jaws, also distinguished by spines supporting their fins; they originated in the early Silurian period and survived until the Permian period.

Mesacanthus, Parexus, Ischnacanthus, all early Devonian.





Chondrichthyes, cartilaginous fishes, are distinct from all other jawed vertebrates which fall under the Teleostomi clade.

Cladoselache, up to 6 feet (1.8m) long, late Devonian.

Stethacanthus, 2.3 feet (70cm) long, late Devonian to early Carboniferous. (385–320 mya)





Placoderms, jawed armoured fish, originated in the mid-to-late Silurian (~430 mya) and were wholly extinct at the end of the Devonian period (~360 mya)

Bothriolepis, around 12 inches (30cm) long, late Devonian. (387–360 mya)

Coccosteus, up to 16 inches (40 cm) long, middle-late Devonian.

Dunkleosteus, at 30 feet long, was the largest of the placoderms, the apex predator of its time, the late Devonian. (380-360 mya)





Sarcopterygii, lobe-finned fish, originated in the late Silurian. (418 mya)

Eusthenopteron, late Devonian.

Tiktaalik, a transitional form between fish and tetrapods (a.k.a. land vertebrates), late Devonian (375 mya)





Actinopterygii, the ray-finned fish, are the most commonplace fish today. They first emerged in the late Silurian, but they didn't start to diversify until the Mesozoic era, so I will save that for later.

 

[arg]

mmmm i want to eat them. as sushi.

i wonder what the species of the distant future will think of us when we're extinct.

 

[viewerfromnihil]

 

[Saparmurat_Niyazov]

Lexington Steele.

 

[Vimana]

Some of my favorite prehistoric animals, therapsids, the predecessors of mammals:

Before learning about them, I originally thought that the first mammals were catlike. Turns out they were more otterlike, and some looked very weird.

 

[Serjeant Grumbles]

Hmm. I'm familiar with the Cynognathus on the bottom, but not the top two. I've looked it up and that middle one, the Ivantosaurus, is of the Biarmosuchia group, the most basal therapsids, and yet I had not looked into the group before. I will post more about therapsids, and synapsids in general, but first, amphibians:

These are all part of the sub-class Labyrinthodontia, a paraphyletic group that excludes modern amphibians (lissamphibians) and amniotes.

Ichthyostegalians (the earliest land-dwelling vertebrates):

Ichthyostega, about 1.5m long, late Devonian. (374-359 mya)

Acanthostega, late Devonian. (365 mya)





Lepospondyls:

Diplocaulus, up to 1m long, Permian period. (299-251 mya)

Ophiderpeton, about 28 inches (70cm) long, late Carboniferous period.





Temnospondyls:

Eryops, a Permian period carnivore, about 1.5-2m (5-6ft) long, 90kg. (200lbs)

Platyhystrix, looks like a Dimetrodon but not at all related, and a lot smaller at 1m long, Permian. (290-270 mya)

Platyoposaurus, 2.5m long, late Permian. (255-250 mya)

Mastodonsaurus, 4-5 meters long (the largest animal of its time), late Triassic. (~200 mya)





Reptilomorphs (as the name would suggest, they are ancestral to reptiles, and all amniotes, by extension):

Seymouria, 2ft long, early Permian. (280-270 mya)

Archeria, a medium-sized aquatic predator, early Permian.

Chroniosuchus, late Permian. (255 mya)

 

[Serjeant Grumbles]

An introduction to synapsids, the "mammal-like reptiles." They are to be distinguished from sauropsids, the true reptiles, it is from synapsids that mammals, their only surviving lineage, are descended. The more basal synapsids are traditionally known as "pelycosaurs," which include some of these:

Ophiacodon, at least 2 meters in length, some species may have been up to 3.6 meters (12 ft) long. Late Carboniferous-early Permian.

The most famous one, Dimetrodon, of the Permian period. (280-265 mya) Often lumped in with dinosaurs, but it is not a dinosaur at all; it predates the age of the dinosaurs, and it is more closely related to mammals than dinosaurs or any modern day reptiles. Dimetrodon grew up to 4 meters (13 ft) in length.

Cotylorhynchus, the largest of the pelycosaurs, the largest terrestrial vertebrates of their time, and the largest up to that time, at up to 20ft in length, early-mid Permian.

Sphenacodon, like a Dimetrodon without the sail, about 3 meters (9.8 ft) in length, early Permian.

 

[Onder]

Thanks and please continue, kind sir.

 

[monoxide_child]

Lexington Steele.

 

[Serjeant Grumbles]

The more advanced synapsids are therapsids, of which there are many interesting ones to be found.

Tetraceratops, of the early Permian (295-285 mya), was either the earliest known therapsid, or another one of the more basal 'pelycosaur' synapsids.




The most basal therapsid group, besides that aforementioned disputed specimen, is Biarmosuchia:

Biarmosuchus, of the late Permian period (~255 mya), up to 1.5-2 meters in length.




The dinocephalians, larged-headed and bulky-bodied:

Anteosaurus, 5-6m long, middle Permian (266-260 mya)

Titanosuchus, mid to late Permian (~255 mya)

Moschops, 5m long, middle Permian (~255 mya)

Estemmenosuchus, 4-5m long, middle Permian (~267 mya)



Gorgonopsids, more slender and generally smaller than the dinocephalians, were top predators of the late Permian period, and include:

Inostrancevia, the size of a bear.

Lycaenops, 1 meter long, about the size of a wolf.



Dicynodonts, the most successful herbivorous therapsids, some of whom lived past the Permian period, such as:

Placerias, of the late Triassic (221-210 mya), up to 3.5 meters (11ft) long.



Cynodonts, the most advanced, mammal-like therapsids:

Cynognathus, of the early-middle Triassic (247-237 mya), 1 meter long.

 

[Serjeant Grumbles]

Some giant arthropods of the Carboniferous period. (360-300 mya) Arthropod size is limited by their tracheal respiratory system, but in this period, there were greater concentrations of oxygen in the atmosphere, so the maximum possible size was much bigger.

Arthropleura, a giant millipede, the largest land arthropod ever (up to 3m long)

Meganeura, a close relative of dragonflies, with a 3ft wingspan.

 

[Onder]

One meter dragonfly is badass as fuck.

 

[Krow]

Really enjoying this thread.

 

[Exodus Prime]

This thread kicks ass. Not seen any of these guys since university. Remember Moschops though...

 

[Krow]

i wonder what the species of the distant future will think of us when we're extinct.

The discovery channel did a really cool thing on this a while back. It's all "what if" but I thought it was really interesting.