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My new purchase of Modern Numis


lostwords

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  • 1 month later...

I really like the Buffalo coin. Can't see myself able to spend that much on one right now but sure do wish I could.

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  • 4 weeks later...

They are nice.

 

Technically, though, the "dinosaur" isn't a dinosaur! It turns out to be something far more interesting in many ways, it's a "mammal-like reptile."

 

About 320 million years ago the hardshell egg laying lineage (amniotes) split into two, and the finback critters are "synapsids"--a term which means one fenestral opening in the skull--more specifically, they are pelycosaurs. Synapsids are ancestors of therapsids, which in turn are ancestral to today's mammals. In fact by the strict rules of cladistics we are considered amniotes, synapsids, pelycosaurs and therapsids ourselves even though we don't lay hardshelled eggs or have a fin on our backs (but our remote ancestors did).

 

Bathygnathus belonged to the specific group of pelycosaurs (sphenacodontia) from which the therapsids arose. Sphenacodontia split into two lineages, therapsids and sphenocodontidae, and bathygnathus is on the latter branch--so it's not quite our ancestor, but it's darned close. Bathygnathus lived about 270 million years ago during the Permian, which was the last period before the start of the Mesozoic (which is typically caricatured as the "age of the dinosaurs"). When I was a kid the "dimetrodon" was fairly famous, it too was a sphenocodontidae and therefore also not quite our ancestor.

 

The other big branch of amniotes is the "diapsids" (two fenestral openings) which are ancestral to two large groups: Lepidosaurs--most reptiles as we know them today (lizards, snakes, amphisbaenians, and tuatara), and Archosaurs (dinosauria and crocodilomorphs--self-explanatory terms). Birds in turn are the only remaining lineage of the dinosaurs; they stem from a branch very closely related to the famous "Velociraptor" and not all that far off from T-Rex. (If you want to visit the real world Jurassic park, go to an aviary.) It doesn't taste like chicken, it tastes like velociraptor.

 

At some point long ago, "anapsids" (no fenestral opening) developed and became the turtles, but exactly how they fit in (are they a sister linage to diapsids or did they branch off of lepidosaurs?) is still unsettled--other extinct lineages with "anapsid" skulls existed but they may have developed independently.

 

OK, I hope you found that digression into "extreme genealogy" interesting.

 

But now... back to fabricated metal discs!

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They are nice.

 

Technically, though, the "dinosaur" isn't a dinosaur! It turns out to be something far more interesting in many ways, it's a "mammal-like reptile."

 

About 320 million years ago the hardshell egg laying lineage (amniotes) split into two, and the finback critters are "synapsids"--a term which means one fenestral opening in the skull--more specifically, they are pelycosaurs. Synapsids are ancestors of therapsids, which in turn are ancestral to today's mammals. In fact by the strict rules of cladistics we are considered amniotes, synapsids, pelycosaurs and therapsids ourselves even though we don't lay hardshelled eggs or have a fin on our backs (but our remote ancestors did).

 

Bathygnathus belonged to the specific group of pelycosaurs (sphenacodontia) from which the therapsids arose. Sphenacodontia split into two lineages, therapsids and sphenocodontidae, and bathygnathus is on the latter branch--so it's not quite our ancestor, but it's darned close. Bathygnathus lived about 270 million years ago during the Permian, which was the last period before the start of the Mesozoic (which is typically caricatured as the "age of the dinosaurs"). When I was a kid the "dimetrodon" was fairly famous, it too was a sphenocodontidae and therefore also not quite our ancestor.

 

The other big branch of amniotes is the "diapsids" (two fenestral openings) which are ancestral to two large groups: Lepidosaurs--most reptiles as we know them today (lizards, snakes, amphisbaenians, and tuatara), and Archosaurs (dinosauria and crocodilomorphs--self-explanatory terms). Birds in turn are the only remaining lineage of the dinosaurs; they stem from a branch very closely related to the famous "Velociraptor" and not all that far off from T-Rex. (If you want to visit the real world Jurassic park, go to an aviary.) It doesn't taste like chicken, it tastes like velociraptor.

 

At some point long ago, "anapsids" (no fenestral opening) developed and became the turtles, but exactly how they fit in (are they a sister linage to diapsids or did they branch off of lepidosaurs?) is still unsettled--other extinct lineages with "anapsid" skulls existed but they may have developed independently.

 

OK, I hope you found that digression into "extreme genealogy" interesting.

 

But now... back to fabricated metal discs!

 

I found it extremely interesting and thank you for taking the time to post it.

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  • 3 weeks later...

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