Monday, March 25, 2013

XenoPermian Biota of the Ural Sea: Elyadia hensonii, a manisuminid


THE XENOPERMIAN OF THE URAL SEA

The Xenopermian is a collaborative effort between Scott, Raven, Zach and myself to outline a very different, speculative world. In some ways this is not all that different than the exercises of Dougal Dixon, After Man and The New Dinosaurs. Rather than speculating on what the dinosaurs would be like if they had not gone extinct, much like his New Dinosaurs or the Spec World project , or project into the future with After Man or The Future is Wild, our team asked the question of ‘what if the Permian Extinction did not happen?

This is the first post about the fauna of the Xenopermian in the Ural Sea region. We have talked about a ‘fossil’ and a faux controversy associated it with. We have talked about the geological staging differences in the XenoPermian timeline, and have even talked about the differences in the world in general under such a different period. We have generalized about the fauna, but now we want to get into specifics. In our last post, we talked about the first faunal member of the Xenopermian, G roma, a pseudochelonid and very derived pareiasaur. Now we are shifting to the trees to talk about our first therapsid, Elyardia hensonii.

Welcome Elyardia: Anomalous Teeth, Beaks and Bites

Elyardia hensonii is an example of a derived anomodont. Anomodonts are one of the major clades of therapsids, very derived synapsids that superceded the pelycasaurs like Dimetrodon. Other famous derviced clades are the gorgonopsids, therocephalians and cynodonts (of which mammals – and you! – are a part of).

The anomodonts had three main clades, as far as we can tell. The two lesser known ones were the venjukoviamorpha (small Laurasian herbivores and possibly omnivores) and the anomocephalians (which were Gondawanan in origin, but large herbivores). The most famous of the anomodonts and most successful in real life were the dicynodonts, of which the relatively famous Lystrosaurus was one. In real life, the other two clades of anomodonts seem to have gone extinct around the Guadalupean. The dicynodonts would be very successful through the Triassic and even survive into the Early Cretaceous of Australia. Again, in real life. All of the anomodonts seem to have had a peculiar front to back chewing mechanism that was developed to the most extreme in the dicynodonts.

XenoPermian Anomodont Phylogeny

All three of the major clades of anomodonts have become important in the Xenopermian. The dicynodonts are the dominant clade, to be sure, filling niches between that of marine herbivore to large herbivore to rodent analog, but the other two are major members of the fauna. The anomocephalans have given rise to the Tiarajudensines. These are derived from Tiarajudens, the earliest known tusked or sabre toothed herbivore. They are split into two clades based on their derived dental arrangement: foreward facing tusks (hastadensids) or sabre teeth (gladiotaurines). They are very large sized herbivores, though rarely gregarious ones. The venjukoviamorpha developed into a cluster of small bodied herbivores and omnivores. They dominate the arboreal and mountain realms. They contest the rodent like niches with juxtarodentia (dicynodonts) in the Arctic and Antarctic regions of Pangaea. They even contest the skies with the two flying diapsid clades. The most common venjukoviamorph in the Ural Sea region is Elyardia hensonii.

Elyardia hensonii is derived from Suminia, a real life fascinating taxon. In the Xenopermian, Suminia was a founder of a fascinating and very important lineage.  E hensonii is a descendent of Suminia as a member of that clade.  Specifically, Elyardia is an example of a nonspecialized, arboreal manisuminid, (handed suminid or suminid with hands). This is a branch of the suminid lineage, those that are derived from Suminia in our fictitious XenoPermian. The other is the Suminopterans, one of the XenoPermian’s three clades of vertebrate fliers.

Something Other This Way Comes: the "Paleo"biology of Elyardia

The manisuminids are mostly, but not exclusively, arboreal. They fill roles similar to squirrels and primates. E hensonii is a relatively basal member of the clade that mostly eats gingko nuts, but supplements its diet by raiding nests for eggs, periodically munching on insects and eating foliage either in tough times or for roughage.  It would be tempting to call the manisuminds the primates of the Xenopermian. There are parallels between the two fictitiously related clades, but there are massive differences as well.

Primates are placental mammals. This allows them to bare live, very developed young. Elyardia and the rest of the manisuminids are definitely not mammals, even if they are fuzzy. They independently developed the ability to bare live young and even suckle their young in a manner similar to monotreme mammals. The live young they bare though are very underdeveloped and must be cared for extensively. However, the time cycle for taking care of their progeny blurs the K/r selection line to some extent. They have fewer pups at a time, but they generally reproduce quite frequently.

One of the great drivers of primate evolution was the presence of fruit. Tropical fruit had a profound impact. Flowering plants do not exist in the XenoPermian. They will arrive, but later, during the alternate Mesozoic and somewhat earlier than their great flowering in the Cretaceous. The presence of the manisuminids and their cousins, the fissonucines, would drive a great deal more innovation in the gingko tree evolution, producing many variants that never existed in OTL. The same held true for changes to coniferous cones as well.


The threats and competitors that the manisuminids would face were radically different than anything the primates did. There are hardly any pterosaurs in the Cenozoic. Nor were there flying primates, which would be the closest parallel with the suminopterans. Pterosaurs are actually one of the biggest problems for manisuminids. While far from large, pterosaurs could and would dive in to raid for young. An adult Elyardia was a serious danger for pterosaurs: their bites are sufficient to lame a pterosaur that they do not outright kill.


Other threats in the trees include, the foliosensids – arboreal insectivorous cynodonts – that take pups and can kill adults if driven to; niictodons (an arboreal parareptilian scavenger with immense bite forces necessary to crush bone) can be a menace if Elyardia is unlucky; and in other habitats, Suminopterans are not above raiding manisuminid nests. Of course, other manisuminids are a problem.

When traversing the ground between copses of gingkoes and other trees, Acerdens (a cynodont that has parallels with badgers), the unnamed ‘sprintocrocs’ and the paratheropods are also problematic. Larger predators rarely notice Elyardia and their kind: they are too much effort for the amount of meat acquired.

The threats from predators have produced some interesting behaviors. Manisuminids are nesters. Depending on the species, how they nest is vastly different. Elyardia nests by finding a large branch and building a large nest from sticks, leaves and other materials. Their hands allow for the innovation that this represents. The nests themselves are often adorned with sticks that have been chewed into a sharpened state and the points are placed outwards.

Elyardia is very gregarious and a colony can occupy a huge tree at very branching point. Every year, the majority of the young leave the colony to either join another or start their own. Most do not succeed, becoming lunch or a snack for some other entity of the XenoPermian.

Likewise, mating season is quite loud and horribly smelly with males jockeying for position in the social structure and females selecting with whom they mate based on the nest construction and displays. Older males, those that have built up their nests over time almost always come out well during the season.

Cha-Cha-Cha-Changes!  Skeletal Changes from Suminia to manisuminids.


Suminia top, Elyardia bottom

The changes to E hensonii from Suminia have been largely constrained to four areas: respiratory, locomotive and cranial. They are driven by the niche and lifestyle of the manisuminids.  Relatively speaking, Elyardia is fairly conservative in its changes, morphologically speaking.

E hensonii and most of the therapsids that made it through the great evolutionary churn that was initiated by the stretched out Siberian Traps of the XenoPermian developed an improved set of lungs. E hensonii came out with an improved tidal breathing apparatus, one that mirrors the method of how the lungs work in modern mammals. Likewise, E hensonii is also endothermic and bounces around the treetops of the Ural Sea region with a great deal of energy.

The changes to the skull are pretty profound on E hensonii compared to Suminia. There are three areas that are of interest. The first is driven by the continued necessities of being a arboreal animal. The suminid line developed binocular vision. Binocular vision developed early on in the suminid line and both the suminopterans and manisuminids retained the trait. The second trait that has developed to an extreme in the manisuminids is heterodontia. The teeth have become more and more specialized. Elyardia has heavy, peglike “incisors” and very molar-like back teeth. This has been driven by the diet related to the gingko nut and its various relatives.


 The chewing action has changed from the basal mill process that anomodonts had, but still processes the food far more than any other therapsids save the cynodonts, other anomodonts and a singular clade of therocephalians. One advantage that the manisuminids have over cynodonts is that they replace their teeth throughout their lives. Although, they are relatively short lives most of the time.

The final collection of traits that has significantly changed from the ancestral sumina is that of locomotion. To speed up, the limbs have become parasaggital. Likewise, the hands have developed into true hands with opposable thumbs. This has allowed the manisuminids to become even more adept climbers and dominate the canopies throughout the XenoPermian world. Their tails have become fully prehensile as well. It is not uncommon to see Elyardia to be dangling by the tail eating or reaching for food.  They are often also used during displays: individuals hanging from their tails and calling and squawking. 

Past the Future

Elyardia's lineage will exist for a long time.  Manisuminids make it past the XenoPermian-Jurassic Extinction and continue to thrive.  They will even make it past the K-E Extinction at the end of the Mesozoic.  They were always a very important member of the fauna, but in the Allozoic (the alternate of the Cenozoic) is when the manisuminids come into their own, being one of the most dominant clades present.  They will outlast the gorgons and parieasaurs.  They will outlast the megafaunal dicynodonts, or at least those not derived from juxtarodentia.  Their response to the greatly increased competition that arose during the late Allozoic glaciations will be fascinating.  However, that is beyond the scope of the XenoPermian, being 213 million years hence.

Notes:

Yeah!  Next Xenopermian done.  The it only took a year and change.  Oy.  There will be two smaller posts in the near future.  The first one will be about our friend the pterosaur.  Given that they are relatively well known from our own timeline I will just touch on them (and risk looking a bit foolish, though I will consult some of the netizens known for their pterosaur knowledge). The next post will not be a year away.

Personally, I loved the touch that Scott put into the first altercation pic: the pseudochelonids of that last post are featured in the beach.  It helps tie, at least visually, the narrative together.

Any questions or comments or corrections, please post.

1 comment:

Scott Elyard said...

Might be the greatest thing ever, having a fictional speculative animal named after me!