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Gyrosprinter / Thar; my new musings on aliens
Topic Started: Feb 24 2010, 03:55 PM (2,649 Views)
Canis Lupis
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Dinosaurs eat man, woman inherits the Earth.

We all know that Earth and Snaiadi animals are quadropeds. Nereid animals are tripeds whereas Pandoran and Furahan animals are hexopods. Creatures from "Alien Planet" are, for the most part, bipeds. With one variation.

It's still a biped, yes. But not the familiar bipeds.

Posted Image

This is a gyrosprinter, presumably descended from a quadroped. Each pair of limbs has merged into one limb so that it has only two limbs: on the front and one on the back.

First, I'd like to know how plausible the gyrosprinter actually is.







But now for the meat of the topic. After watching "Alien Planet" again, I started thinking about a world with a gyrosprinter-like sapient. From there, I started thinking about a world ruled by various gyrosprinter-like creatures. Antelope, lion, whale, mole, and monkey-like animals seem the most plausible creatures for this limb structure. Obviously, flying niches would be out of the question unless they evolve what the flying lizards of Borneo have evolved.




So, how plausible does a world dominated by vertical bipeds (bipeds with a limb structure like a gyrosprinter) sound?




BTW, I'll be adding random creature descriptions here and there on this topic. I'll see if I can add a picture of each.
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Margaret Pye
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Hmmm...

Well, if I can avoid falling over forward or backward, I dare say that thing can avoid falling over sideways. It'd have to be good at leaning into corners!

Would it work better with long sideways balancing-pole extensions?

So how does its evolutionary history work? Descended from a quadruped and the limbs fused? Sounds plausible, but I can't think what selective pressures would cause that, not off the top of my head. Any suggestions, anyone? Maybe it started out with a diamond-shaped body with legs on each side, like mulefa, and then lost the side legs? (Maybe they became extremely specialised - wings or something - and the creature then lost its specialised lifestyle?) Maybe it's descended from an inchworm?
My speculative dinosaur project. With lots of fluff, parental care and mammalian-level intelligence, and the odd sophont.
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Empyreon
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Are you plausible?

If I remember correctly, the gyrosprinter does have some sort of complex balancing organ located in the "shoulder blade" region.

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Descended from a quadruped and the limbs fused?

From other pictures of it, that seems to be the method. (And people mock the prolemuris...) As far as selective pressures, I've always had a hard time skulling that one out. It seems to me that the inherent balance involved with having feet spread out on the ground was too much of an advantage to evolve away from.
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food for thought
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colddigger
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wait, are you trying to figure out the evolution of the gyrosprinter? if so it's almost certainly from a four legged beast, he has several fine sketches of them in his book that definitely show this.



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Canis Lupis
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Dinosaurs eat man, woman inherits the Earth.

Yeah, I'm pretty sure it's a quadroped-descendent.

And yes, it does have a large balancing organ.
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Ddraig Goch
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Ar hyd y nos

The balancers are called halters, and can also be found on several species of Terran fly.
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Canis Lupis
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Dinosaurs eat man, woman inherits the Earth.

Is that what they are called in the gyrosprinter? Halters?



I was thinking that, for my world dominated by similar creatures, that the organisms would have two brains. One in their head to direct the senses and another between the two vertebral columns to mainly focus on the balance.
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Empyreon
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Are you plausible?

Most nereids tetrabrachs have a similar neural setup. The sensory stalk houses a ganglion that in some species is really quite developed, while the central brain is located in the "shoulder" region.
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Margaret Pye
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Halteres. E on the end.
My speculative dinosaur project. With lots of fluff, parental care and mammalian-level intelligence, and the odd sophont.
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T.Neo
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Well, considering limb arrangements on Darwin IV are very confusing to say the least, I doubt it. Side-to-side limb fusion? Maybe, but I think keeping all limbs seperate would be ideal for a fast running organism.

As for the prolemuris and their cousins the Na'vi, the issue isn't the limb fusion but rather the fact that in the latter there appears to be no trace of the second set of fingers or evidence of the limb fusion...
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Pando
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I think that a planet dominated by gyrosprinters could live, that is, unless there are also quadrupeds on the planet...

I think that they could live if they had a big balancer, but that means that big creatures and creatures that live in tight forests probably couldn't live. And how would diggers, flyers, and arboreal creatures live?
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Canis Lupis
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Dinosaurs eat man, woman inherits the Earth.

Well, if the limbs fused early enough, there might not be any external evidence of the limb fusion. Keep in mind that in "Avatar" we were never shown a skeleton of a Na'vi. Just of a great leonopterix. So perhaps there is internal evidence, just like there is internal (but no external) evidence that humans possessed a tail at some point.






Yeah, the limb fusion idea (for the gyrosprinter) seems rather counter-intuitive to me. It would be easier to just remain a quadroped.

The idea I have for my creatures is a bit different. Their ancestors were quite similar to Earth fish, except they possessed no caudal or pectoral fins. Just dorsal fins and ventral fins, which were all extensions of the ribs that they would undulate to move (the ribs in this phyla run to the back and to the front rather than just to the front).

When one species, with a dorsal fin more used for display than movement, began to make its way onto land, a portion of the ventral fin evolved to push it along. Sort of like the foot of that genetically deformed snake (there was once a snake born with one foot). From their, a front portion of the ventral fin evolved to aid the creature in pursuing its fast arthropoid prey and to help it not be so cumbersome on land.

I'll see if I can get some taxonomy posted soon. I've kind of been obsessing over "Alien Planet" for the past week.
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Ddraig Goch
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Ar hyd y nos

Margaret Pye
 
Halteres. E on the end.

Ah, thanks. Knew it was something like that.
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Canis Lupis
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Dinosaurs eat man, woman inherits the Earth.

Well guys, I'm working on basic taxonomy up to the class level.

In the kingdom Tharthazoa (meaning "animals from Thar"), I have decided that there will be five phyla. These five phyla are as follows:

  • Monsorda - means "mountain filter" - while not the most diverse of the Tharthazoan phyla, they are among the largest. The largest resemble large black smokers. The only differences are that these are biotic and exist in warm tropical waters. This phylum is characterized by the presence of few organ systems, the only ones being a primitive digestive system, reproductive system, and a respiratory/circulatory system, which are all fueled by the movement of water through their pores. There are two classes of monsors, both detailed later.
  • Anokagastra - means "open stomach" - in terms of Tharian evolutionary history, this phylum is a direct descendent of the mobile, worm-like larvae of the monsors. While diet and body forms are highly diverse, behavior is not. This phylum, like nematodes of Earth, is made mostly of parasites (the only exception being the circorids). They are characterized by the presence of an open digestive system. In other words, they have a stomach-like chamber just below their skin, leaving only a central column for the heart, respiratory system, reproductive system, and nervous system. There are three classes of anokagastrids, all detailed later.
  • Tulimusca - means "muscle ring" - this phylum, in terms of evolutionary history, arose when the anokagastrids began to feed upon each other. A particular genus of anokagastrids began to evolve a primitive exoskeleton to prevent predators from feeding upon it. This design proved effective and it served as an effective body plan to allow the creatures to grow larger than their non-shelled counterparts. Creatures within this phylum are characterized by possessing a nearly spherical shell which serves to protect their tentacle mouth. Two classes shoot this tentacle out to quickly snap up food, but two other classes have evolved the tentacle for locomotive purposes. The phylum gets its name from the rings of muscles surrounding its central stomach core, known as a semi-closed digestive system. Their digestive system possesses no muscles of its own so it has to rely on the muscles that move the organism. To grind the food, the muscle ring constricts around the stomach core. Doing this continually digests the food enough so it can be squezzed out of a hole in the posterior. This is also the first phylum showing the presence of eyes. There is considerable variation in tentacle shape, shell shape, and shell coverage, making this phylum quite diverse. There are four classes within this phylum, all detailed later.
  • Polykephala - means "many brains - unlike on Earth in which creatures have continually evolved increased cephalization (senses around the head which stores the only brain), creatures of Thar have been continually evolving increased dicephalization. This process involves the formation of two brains and evolving senses around these two brains. The polykephs have mastered the first step and possess one fully formed brain in the anterior with senses coalesced around it. They also possess multiple ganglia in the posterior with senses coalesced around them. It has been suggested that a polykeph gave rise to the dikephs (a phylum showing true dicephalization), but this is not very likely (see the next bullet). In terms of evolutionary history, it is likely that the polykephs are descendents of the trastims (a class of tulimusks) which used their tentacle to drag them across the sea floor. Eventually as predators became speedier, a genus of the class trastimia most likely evolved scutes from their shell and used these to push them along. Eventually, these scutes evolved into fully effective legs allowing the animal to hurry across the ocean floor. The number of legs varys considerably in this phylum. In fact, early classification attempts grouped polykephs into classes based on the number of limbs. But when this method proved polyphyletic, they were grouped by respiratory method and mouth type. This yeilded four monophyletic classes, all of which will be detailed later.
  • Dikephala - means "two brains" - as mentioned above, it was once thought that this phylum descended from a polykeph. This hypothesis was based around the nervous systems of both phyla. It appeared that the nervous system of the dikephs evolved directly from the polykeph's nervous system, but fossil evidence disproved this theory. The critical difference was in the different sciochord ("knowing chord", so named because this chord connects a brain to a brain or a brain to the ganglia) structures. In polykephs, one sciochord grows from the first brain then branches into multiple ganglia once it reaches the posterior (resembling frayed string). In the dikephs, however, two sciochords grow from the first brain then reattach to the second brain in the posterior (resembling an oval). Fossil evidence revealed that these traits appeared at roughly the same time: 50 million years. It appears that the dikephs evolved from the trastims as well, except they evolved a more advanced nervous system. With the initial lack of legs, early dikephs were sessile filter-feeders taking niches similar to anemones and corals sometimes growing on the side of the monsors. Thus, polykephs gained the upperhand for a time. But once the dikephs lost their bulky shell, they began to become more mobile, resembling a strange cross between a hagfish and a sea cucumber. Eventually, bones began to surround the sciochords and the dikephs began to take over the world. As the ribs evolved, effective limbs were developed allowing the dikephs to swim and eventually dominate the land in strange veritical biped forms. There are seven classes in this phyla, making it highly diverse, but still second to the polykephs in terms of diversity. Details on these seven classes will be given later.





Thoughts and opinions on the Tharthazoan phyla? I'll be getting to the classes later tonight.
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colddigger
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Canis Lupis
Feb 26 2010, 03:56 PM
I've kind of been obsessing over "Alien Planet" for the past week.
i prefer the book myself

*smugface poshface*

how do you think up these groups anyway?
Edited by colddigger, Feb 27 2010, 08:43 PM.
Oh Fine.

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