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| [ARCHIVED] Coconut Crabs | |
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| Topic Started: May 14 2010, 01:17 AM (4,023 Views) | |
| Pando | May 14 2010, 01:17 AM Post #1 |
Obey or I'll send you to the moon
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As the Chinese swamp of 120 MYF nears its end (got a batch ready) I've been wondering about Coconut Crabs. The coconut crab is unique among arthropods that as they went on land their gills didn't turn into body tubes, but is currently in a proto-lung. In the Postozoic it goes further and turns into a real lung, allowing them to grow bigger. What is the biggest size they are able to achieve and what diversity can they have? I'm guessing that they will be able to grow as big as a lot of vertebrates as some seascorpions (including a 7 foot long one) went on land and arthropleura existed. |
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| The Dodo | May 14 2010, 01:22 AM Post #2 |
Prime Specimen
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That depends on competiton, when arthropleura existed there wasn't as much competiton for large herbivore niche. Assuming there is room for them to get into a land niche they could evolve. Also, would the exoskeleton slow them down? |
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| Pando | May 14 2010, 01:24 AM Post #3 |
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Obey or I'll send you to the moon
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After the 90 MYF extinction a LOT of niches were open, and unlike the P-Tr many groups filled the niches. I'm assuming that they can share some of the rodent niches that the rodent geckos now hold. |
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| The Dodo | May 14 2010, 01:28 AM Post #4 |
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Prime Specimen
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Would the coconut crabs survive this extinction? |
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| truteal | May 14 2010, 01:29 AM Post #5 |
forum bigfoot
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it would probably only get bigger on islands (and if other vertebrates didn't get there soon enough) a coconut crab with the ecological niche of an orangutan would be quite interesting |
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My sporadically updated Youtube page Do you get it? I hardly ever come here so I'm like something a cryptozoologist would study | |
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| Pando | May 14 2010, 01:35 AM Post #6 |
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Obey or I'll send you to the moon
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Coconut crabs diversified within the 90 million years, and survived. I should really post a 90 MYF extinction thread, but when I have more 25 and 90 MYF biomes done. I like your idea Truteal. After the extinction plus the flooding of the world brought a lot of islands free of vertebrates, where it can survive. That's how the flying fish of 200 MYF live (by eating island arthropods). But a coconut crab would be too much for a flying fish to tackle. |
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| The Dodo | May 14 2010, 01:42 AM Post #7 |
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Prime Specimen
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Some coconut crabs already climb trees, it wouldn't be to hard to imagine some living up there. Wouldn't the exoskeleton cause some problems. |
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| Pando | May 14 2010, 01:48 AM Post #8 |
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Obey or I'll send you to the moon
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Why? They just need to get rid of that big thing at their butt and their okay to go. How big can they get with their exoskeleton? Breathing is not a player with them anymore since they have lungs. |
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| The Dodo | May 14 2010, 01:53 AM Post #9 |
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Prime Specimen
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I think they're approaching their size limits today, but with the lungs they can get bigger. It might restrict their movement a bit. |
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| Pando | May 14 2010, 02:59 AM Post #10 |
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Obey or I'll send you to the moon
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Their body might get a tad wider to accommodate the lung. And no, coconut crabs are not at the highest size possible. Arthropleura and land sea scorpions existed. But that would be one heck of a molting! |
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| The Dodo | May 14 2010, 03:22 AM Post #11 |
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Prime Specimen
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I meant the limits they can get to today in their present form. |
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| Pando | May 14 2010, 03:23 AM Post #12 |
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Obey or I'll send you to the moon
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What limits? |
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| The Dodo | May 14 2010, 03:27 AM Post #13 |
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Prime Specimen
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Limits in size they can get to in their current form today with their breathing mechanism and the planets atmosphere. |
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| Pando | May 14 2010, 03:30 AM Post #14 |
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Obey or I'll send you to the moon
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Lungs will take care of most atmospheric issues. And also, in a global swamp/rain forest there will be a lot of oxygen. What kinds of diversity can they have? I'm guessing the biggest they can be is about 2-3 feet long with lungs (body length, excluding arms). Then there can be a lineage of carnivorous primates with strong jaws specialized for future coconut crabs. |
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| MitchBeard | May 14 2010, 05:06 AM Post #15 |
proud gondwanan
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One of the biggest problems arthropods have when it comes to getting big is the fact that their muscles are essentially inside their bones. At the moment crabs have all the muscles that move their legs in the joints of the leg that they move. This means that the bigger they get, the more they need, and the less room there is for other important things like nerves and circulation. As I have displayed. What they need to do to get really big is to have the muscles inside the thorax and have tendons running down to segments of the legs that they control. There could be other ways to do it, but none that come to mind. Otherwise, coconut crabs are ripe for speciation. Mostly they specailize on coconuts, but can take other fruit, vegetation and even carrion. There is even a reported incidence of a coconut crab killing and eating a rat inside a trap that was set to tag the crabs. I think they are definitely not getting much bigger than how big they are at the moment, maybe 10-30% bigger in a higher oxygen atmosphere, but bigger than that would be pushing it. There are still a lot of niches that they can take inside that range though. I think the orangutan crabs needs to happen  You can use my gympie crab if you want too man.
Edited by MitchBeard, May 14 2010, 05:21 AM.
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