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Parasitic vertebrates
Topic Started: May 14 2017, 03:53 PM (1,277 Views)
HangingThief
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The thing with the shark and the eels clearly isn't natural. Probably has something to do with the Plum Island Animal Disease Testing Facility.
Hey.


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IIGSY
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What about tetrapods? Could a vampire bat continue specialization for a parasitic life? Its actually pretty reasonable if you think about it. It could lower it's metabolism for starters.
Projects
Punga: A terraformed world with no vertebrates
Last one crawling: The last arthropod

ARTH-6810: A world without vertebrates (It's ded, but you can still read I guess)

Potential ideas-
Swamp world: A world covered in lakes, with the largest being caspian sized.
Nematozoic: After a mass extinction of ultimate proportions, a single species of nematode is the only surviving animal.
Tri-devonian: A devonian like ecosystem with holocene species on three different continents.

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Phylogeny of the arthropods and some related groups


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kusanagi
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I have no idea other than that teleosts can exist as faculative endoparasites. In tetrapods obligate sanguinivory is found in a clade of bats and faculative vampirismis documented in two clades of passerine birds. Seagulls will also snatch living tissues from surfacing whales which is a form of parasitism and like the other birds and the bats they can obviously fly. Is flight a constraint for ectoparasitic tetrapods? I have no idea because parasitic behaviour is so rare in vertebrates.
Edited by kusanagi, Jul 20 2017, 05:37 PM.
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Greta
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Mostly because vertebrates tend to require higher energy and protein quantities than simpler invertebrates and fish, so a vertebrate endoparasite would eat its victims to death.

Still, I have one decent endoparasite in Lemuria, the paleognath Titicula.

My thought too, but yours is better expressed.

In truth, many mammals are parasitic, regularly engaging in kleptoparasitism, there the cost to the host is not their body but their food and hard-earned useful stuff. Further, predation could be thought of as quick lethal parasitism.
Edited by Greta, Aug 24 2017, 12:55 AM.
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kusanagi
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But facultative endoparasitism exists in an eel, and obligate endoparasitism in pearlfishes.

Think what was lost in fishes - vertebrae in hagfishes, paired fins/legs several times, other fins several times, eyes, lateral line. Deep sea teleosts are notoriously simplified by progenesis in a way no sarcopterygians or elasmobranchs are, specifically to overcome the stresses of abyssal life. Using the metabolisms of deep sea teleosts as a basis some vertebrates - or at least teleosts - can evolve atrophied organ systems and low energy requirements fairly easily.
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Noah's Raven
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When I was in high school, I had this wacky theory that alvarezsaurids might have been obligate sanguinivores. The idea was that they used those stumpy foreclaws with all those powerful muscle attachments to latch onto the legs of much larger dinosaurs, bite open a blood vessel, and lap the blood up with their tongues like hummingbirds.

Not very plausible, I know, but it's a very fun idea.
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VALLES INCOMPERTUS: A Natural History of Earth's Last Uncharted Land
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kusanagi
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No one knows what those forearms were for: the animal was not an anteater any more than a vampire bat. Ignore the sternum and the claw, and the shortness and strength of the forearms is shared by tyrannosaurs and abelisaurs. The claw is perhaps a relict from a more raptorial past.
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Noah's Raven
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kusanagi
Aug 24 2017, 12:00 PM
No one knows what those forearms were for: the animal was not an anteater any more than a vampire bat. Ignore the sternum and the claw, and the shortness and strength of the forearms is shared by tyrannosaurs and abelisaurs. The claw is perhaps a relict from a more raptorial past.
I always thought the myrmecophagy explanation was bullshit; the poor thing would have to give termite mounds a belly-rub just to get those claws to reach it. But I don't get the vestigial explanation either. If they're an evolutionary holdover, why are the muscle attachments so strong, or the claws so robust?
"In the land of the blind, the one-eyed man EATS EVERYONE." --Dromaeosaurus

VALLES INCOMPERTUS: A Natural History of Earth's Last Uncharted Land
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kusanagi
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There doesn't seem to be a reason: its just how tyrannosaurid and abelisaurid forearms reduced in size whilst retaining strength. A number of theropods have large claws on digit II. Ignore the claws and the combination of strength and shortness is not atypical for atrophied theropod forearms. The sternum is however a puzzle if those forelimbs are not functional as digging organs: incidentally the forearms are built for tearing - prey? - not for digging. Living things have evolutionary histories creating organs that are no longer functional: the queer sternum is a puzzle - does pleiotropy explain the large heads and strange sternums of alvarezsaurs and birds? Though the cursoriality of alvarezsaurs resembles that ornithomimosaurs they do not have an expanded hindgut as in herbivores: maybe they pecked at plants but they were foraging insectivores, perhaps snapping at small frogs and lizards but taking smaller prey than the troodontids at the same localities. Mononykines are habitat specialists though brain endocasts show aquatic(!) adaptations. So far a coelurosaur called Haplocheirus is the most probable alvarezsaurs ancestor, whilst the basal ornithomimosaur(?) Nqwebasaurus. compsognathids and even megaraptors all show similarities.

Returning to vertebrate parasites: pentastomes latch onto soft tissues with four incompletely arthrodised legs and feed by muscular suction. Vertebrate jaws can latch on be it as rasping catfishes or candiru or vampire bats. As enamel is uneccessary it might or might not be lost in our hypothetical teleost but teeth are how gnathostomes pierce surfaces. Is it possible that external gills would be absent if respiration is through the dermis? There is obviously no need for a swim bladder. The smallest frogs and teleosts are within the size range of invertebrate endoparasites. A problem is the life cycle as an ova must be ingested to enter the intestinal tract. Alternatively larvae could locate a host if they are free swimming but eggs would still have to be excreted through the gut, else out of nasal openings etc. In the sea larvae can simply approach and infect fishes or other gill breathing animals.
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IIGSY
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kusanagi
Aug 24 2017, 02:50 PM
There doesn't seem to be a reason: its just how tyrannosaurid and abelisaurid forearms reduced in size whilst retaining strength. A number of theropods have large claws on digit II. Ignore the claws and the combination of strength and shortness is not atypical for atrophied theropod forearms. The sternum is however a puzzle if those forelimbs are not functional as digging organs: incidentally the forearms are built for tearing - prey? - not for digging. Living things have evolutionary histories creating organs that are no longer functional: the queer sternum is a puzzle - does pleiotropy explain the large heads and strange sternums of alvarezsaurs and birds? Though the cursoriality of alvarezsaurs resembles that ornithomimosaurs they do not have an expanded hindgut as in herbivores: maybe they pecked at plants but they were foraging insectivores, perhaps snapping at small frogs and lizards but taking smaller prey than the troodontids at the same localities. Mononykines are habitat specialists though brain endocasts show aquatic(!) adaptations. So far a coelurosaur called Haplocheirus is the most probable alvarezsaurs ancestor, whilst the basal ornithomimosaur(?) Nqwebasaurus. compsognathids and even megaraptors all show similarities.

Returning to vertebrate parasites: pentastomes latch onto soft tissues with four incompletely arthrodised legs and feed by muscular suction. Vertebrate jaws can latch on be it as rasping catfishes or candiru or vampire bats. As enamel is uneccessary it might or might not be lost in our hypothetical teleost but teeth are how gnathostomes pierce surfaces. Is it possible that external gills would be absent if respiration is through the dermis? There is obviously no need for a swim bladder. The smallest frogs and teleosts are within the size range of invertebrate endoparasites. A problem is the life cycle as an ova must be ingested to enter the intestinal tract. Alternatively larvae could locate a host if they are free swimming but eggs would still have to be excreted through the gut, else out of nasal openings etc. In the sea larvae can simply approach and infect fishes or other gill breathing animals.
Would it be possible for a vertebrate to evolve cyst like eggs?
Projects
Punga: A terraformed world with no vertebrates
Last one crawling: The last arthropod

ARTH-6810: A world without vertebrates (It's ded, but you can still read I guess)

Potential ideas-
Swamp world: A world covered in lakes, with the largest being caspian sized.
Nematozoic: After a mass extinction of ultimate proportions, a single species of nematode is the only surviving animal.
Tri-devonian: A devonian like ecosystem with holocene species on three different continents.

Quotes


Phylogeny of the arthropods and some related groups


In honor of the greatest clade of all time


More pictures


Other cool things


All African countries can fit into Brazil
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kusanagi
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To be honest I'm unsure how animals like pentastomes do it: they must have a chemical defence against digestion? But depending upon the site of infestation it may not be neccessary to pass through a tummy.
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IIGSY
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kusanagi
Aug 24 2017, 05:32 PM
To be honest I'm unsure how animals like pentastomes do it: they must have a chemical defence against digestion? But depending upon the site of infestation it may not be neccessary to pass through a tummy.
Maybe in the lungs or mussel tissue?
Projects
Punga: A terraformed world with no vertebrates
Last one crawling: The last arthropod

ARTH-6810: A world without vertebrates (It's ded, but you can still read I guess)

Potential ideas-
Swamp world: A world covered in lakes, with the largest being caspian sized.
Nematozoic: After a mass extinction of ultimate proportions, a single species of nematode is the only surviving animal.
Tri-devonian: A devonian like ecosystem with holocene species on three different continents.

Quotes


Phylogeny of the arthropods and some related groups


In honor of the greatest clade of all time


More pictures


Other cool things


All African countries can fit into Brazil
Offline Profile Quote Post Goto Top
 
kusanagi
Adolescent
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Yes bury in from outside like swan mussel and botfly larvae or go in and out via the gills. Its not too hard to imagine.
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Bassoe
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Jul 20 2017, 01:22 PM
I wonder if you could make an amphibian with parasitic tadpoles. Like, imagine if their environment wasn't suitable for completely waterbound young to survive (toxic chemicals, inconsistent climate); a parasitic larval stage sounds like a good solution, if you could make the transitional forms work.
It isn't that great a leap from this, although it would be less parasitism and more swapping out their oviparous reproductive systems for viviparous ones.
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