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Terra Avis; and yet another project
Topic Started: Jan 8 2009, 05:03 PM (2,050 Views)
Carlos
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Adveho in me Lucifero
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In addition to Terra Alternativa (not finished yet) and to WIW (also not finished), I present you another of my twisted alternate worlds. This one is almost finished; I just need to present individual species/clades.

The following is an "introduction", if you wish:
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Terra Avis (Terra=Earth, Avis=Bird) is my speculation of how a world dominated by birds would look like. It diverged from our world in the K-T boundary, after the disappearence of dinosaurs, pterosaurs, and non-neornithe birds. Mammals survived, but there are no true marsupials nor placentals, just basal therians, monotremates and the flying volaticotheres; none of these groups achieved dominance over the terrestrial megafauna niches, though monotremates (and some otter like therians) gave rise to quite large aquatic forms and volaticotheres occur in most landmasses; shrew and mustelid like therians occur in the northern landmasses. Reptiles like crocodiles, tortoises and some big lizards and tuataras did produced large forms, but, just like on our Earth, they are also limitated. Instead, it were neornithes, the pioners of archosaur success, that, in terms of diversity, species count and biomass, became the ultimate rulers of the world.

On land, the vast forests and grasslands are inhabited by huge flocks of fast, flightless grazers and browsers. Ratites, during the Paleogene, took most of these niches; ostriches were dominant in Eurasia, but afterwards they lost ground for invaders from Africa and North America: large, flightless galliformes and gruiformes respectively. Today, however, ostriches still are common, with 9 species in Eurasia and Africa and 3 in the Americas. Rheas were dominant in South America for most of the Cenezoic, but the Great Faunal Interchange caused their demise, with now as much as 3/4 species, barely more than in our world. In Oz, cassuwaries, isolated from the other landmasses, still remain the dominant omnivores, though emus were largely replaced by anseranatids; kiwis also occur outside of New Zealand, having produced "avian echidnas" (whereas monotremates produced mole like forms, which birds never did). Flying paleognaths still exist as well, besides the obvious tinamous, there's also rail, shorebird and mesite like lithornids (none of these are present on present Terra Avis).

Galloanseres, composed of Anseriformes and Galliformes, which proved to be very adaptable on our world, achieved major roles in megafaunal niches. Pheasants took the niches in our world occupied by pigs and large rodents in Eurasia (in the Americas they were taken by turkeys, curassows and tinamous, and in Oz by megapodes), while peafowl relatives became antilope analogues in Africa and southern Eurasia; guinea fowl produced both mountain dweelers and a bird's answer to a black rhino (convergently similar to the Australian cassuwaries). Anseriformes, besides familiar waterfowl, large browsers and grazers; South America has giant screamers as the main browsers, nearly all continents have large flightless geese browsing and grazing, and Oz has dromornids; there's also some waterfowl that became fligthless divers, the avian analogues of manatees and dugongs. Oz also has fast running, grazing relatives of the magpie goose. On islands like Madagascar and New Zealand, ratites are the main browsers, but waterfowl are the main grazers.

In the seas, the absence of sea mammals (aside from beaked whale like monotremates and leopard seal like therians in the poles) allowed birds to diversify, though they never produced fully marine forms, since they still need to lay eggs. Penguins and plotopterids are the dolphins and seals of Terra Avis, with cormorants, loons and auks as smaller fish hunters. In the absence of baleen whales pelicans and swanmingoes (derived flamingoes that resemble swans) taking the main filter feeding niches; while they haven't produced flightless forms, they are still huge, the biggest reaching 8 meters of wingspan. Gannets and boobies are also more diverse than on our Earth, and so are tropicbirds (there's no frigate birds on Terra Avis).

The predatory niches are occupied by Acciptriformes and Strigiformes; owls produced flightless, cat like forms, while large eagles similar to the Haast's eagle occur all over the world, and flightless relatives of the secretary bird dominate the plains of Eurasia and Africa; a similar niche is occupied by phorusrhacids in the Americas. Bear and hyena analogues are either flightless vultures or New World vultures, with caracaras, herons/storks and ravens being small oportunists.

Mousebirds are common arboreal birds, the squirrels of TA, while hoatzins have produced "sloth birds". Parrots take similar niches to those of primates; ironically, though, they haven't produced a grassland dweeling form akin to hominids. That niche was taken by ground hornbills, which might produce a future sophont
Lemuria:
http://s1.zetaboards.com/Conceptual_Evolution/topic/5724950/

Terra Alternativa:
http://s1.zetaboards.com/Conceptual_Evolution/forum/460637/

My Patreon:

https://www.patreon.com/Carliro

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Carlos
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Adveho in me Lucifero
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AFTER AN ETERNITY I now answer: I find quadrupedalism in birds, while not totally impossible, very unlikely, and mostly impratical when bipedal birds are present. I have a linage of birds that could be considered quadrupedal, but even so they walk around much differently than you would expect from a quadrupedal animal, and that can be best described as "hooping". These are of course, pelagic fish hunters, too specialised to produce flightless quadrupeds (though I might include inland azhdarchid like forms)
Lemuria:
http://s1.zetaboards.com/Conceptual_Evolution/topic/5724950/

Terra Alternativa:
http://s1.zetaboards.com/Conceptual_Evolution/forum/460637/

My Patreon:

https://www.patreon.com/Carliro

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