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Priory_of_Sion

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Posts posted by Priory_of_Sion

  1. On 2/15/2017 at 2:41 PM, Collimatrix said:

    What?!  Choristoderes have been known to be oviviparous for ages now!  Are they not considered archosaurimorphs anymore or something?

    Don't know

    Quote

    The phylogenetic position of choristoderans is also ambiguously resolved in this analysis, but is constrained to the base of either Lepidosauromorpha or Archosauromorpha. Six synapomorphies support the position of choristoderans within Archosauromorpha and Lepidosauromorpha in each case (see Synapomorphies of some trees that include choristoderans in Results). It should be noted that only three additional steps are necessary to force the position of choristoderans outside Sauria, and the present taxonomic and character sample is not focused on non-archosauromorph diapsids. Therefore, this result invites future work testing the phylogenetic position of the group within Neodiapsida in light of the information provided here.

     

  2. 17 minutes ago, Collimatrix said:

    What does the algae do?

    I believe it takes up excess carbon dioxide and provides oxygen in the often oxygen poor environments that these salamanders are found in.

    Here's a paper that goes a little more in depth about the relationship. 

     

    Pereira_eggs-300x212_f_improf_300x212.pn

  3. Ambystomatids are a group of salamanders living in North America and are known collectively as Mole Salamanders because most of them live underground for the majority of their adult life. Some of the more well known members of this group are the Tiger Salamander and Mexico’s Axolotl which is known for not metamorphosizing. This paedomorphic state is actually not that uncommon among the ambystomatids as the common Mole Salamander can be found in a paedomorphic state retaining much of its larval characteristics but being sexually mature. However, all of these individuals that don’t metamorphosize can be induced to do so, including the Axolotl. This is not nearly the strangest aspect of this clade of salamanders though, it gets a hell of a lot stranger with a group of species around the Great Lakes. 

    D53xV1x.png

    My sexy hand holding an adult paedomorphic Mole Salamander(ambystoma talpoideum) and some dumbass fucking bug 

    The laterale-jeffersoniaum complex of mole salamanders includes within it numerous populations of unisexual salamanders that have are hybrids of up to 4 different species. Their method of reproduction is also unique from other unisexual tetrapods, as these salamanders all share an identical cytoplasm make up from a female ancestor dating back anywhere from 2.4 to 3.9 mya, but steal the genomes from males of the other relative salamander species in the area and incorporate their genome into their all female offspring. This has created a number of different combinations of diploid and polyploid unisexual ambystomids living around the Great Lakes, which were considered distinct species based on their morphologies(such as the Silvery salamander) until herpetologists realized that these fuckers aren’t really species but just a fucking car accident of genetic material that seems to be quite adaptive compared to other unisexual organisms which usually just have clonal offspring (which some of these ambystomids do as well after utilizing sperm to stimulate cell division without actually incorporating the male's genetic information at all). This is thought to explain the relatively old origin of these populations. This mode of "stealing" genomes has been termed kleptogenesis. 

     

    Here's a phylogeny of this complex, and what's weird is that the unisexual ambystomids do not really incorporate the genome from the most closely related species the Streamside Salamander

    A6dLJpM.png

     

    LL and JJ represent good species, the laterale and jeffersonianum, but you also have some examples of some polyploid unisexual salamanders here that have combinations of the genomes from each of these species. They can also include genomes from texanum and tigrium. 

    Figure-2-Ambystoma-laterale-and-unisexua

    Figure-3-Ambystoma-jeffersonianum-and-un

     

    I still don't understand it either. 

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