At last...
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Euornithes, as a whole, have been masters at colonising the seabird niches; since the Cretaceous there's basal toothed seabirds like the ichthyorniformes and the hesperorniformes, and both groups are still very common on Spec, having taken the niches of seagulls, terns, skimmers, auks, flamingoes, vultures (a linage of ichthyorniformes abandoned the sea and became scavengers), cormorants, darters and penguins (in the northern hemisphere obviously). Neornithes also produced their own handfull of seabird species; petrels and tropicbirds cruise Spec's skies, shorebird like paleognaths gather in the coast lines, and penguins rule supreme over the southern oceans. However, there's another linage of seabirds that occur in Spec, and which gave rise to the biggest flying birds [aside from the rocs?] that occur in this world.
Perhaps interesting to note is the fact that there's no gannets nor pelicans in Spec, and its albatrosses are reduced to a few species from the south, often refered as "p-Phobetria". Instead, the pseudodontorns, or "false-toothed birds", rule over the large seabird niches.
Pseudodontorns, unlike most marine neornithes, do not belong the "waterbird clade", nor are they p-Charadriiformes (which too never evolved on Spec), but rather they are actually relatives of waterfowl and fowl, and thus they must have diverged from them already in the Cretaceous, when Galloanserae was already well defined. At this time, the ornithocheiroid pterosaurs ruled over large "seabird" niches, but towards the Eocene most of them disappeared, with modern species living as relics here and there. This left a vacuum to be filled, and ichthyorniforme seabirds took advantage, giving rise to big forms; however, towards the Miocene, they started to decline, and so pseudodontorns occupied the niche.
As the name suggests, these birds don't have true teeth (lost forever by the first neornithes, though genetic manipulation does cause pseudodontorns to grow actual teeth), but teeth-like serrations in the bill, which are used to grab prey like ammonites, small/baby baleen squids and fish. Pseudodontorns, like most seabirds (and unlike Anseriformes and Galliformes), have nidiculous chicks, which need parental care for a shorter period of time than other seabirds, up to a month and a half in the bigger species.
Pelagornithidae
The "typical" pseudodontorns, they are mostly gannet, booby and albatross like forms
North Atlantic Grannet (Odontomorus bassanus)
Grannet colonies are a typical sight in the North Atlantic. Fairly larger than their HE analogues, they have wingspans of up to 3 meters; some individuals are reported to reach wingspans of up to 3.7 meters. One of the largest flying seabirds of the northern hemishere, they dive in the manner of HE's gannets, and then swim after their prey underwater like them; in fact, Ondontomorus is the pseudodontorn genus with the shorter and stronger wings. Its still a good fliers though, spending most of its time soaring above the sea in the manner of other pseudodontorns. Unlike HE's gannets, Spec's grannets are slightly more diverse, with three Pacific species in addition to the two Atlantic ones.
Spectacled Hobbie (Adamastosula pelagica)
A quite common specie of hobbie, this bird occurs in the Pacific ocean (sometimes, its range overlaps with the Northen Pacific Grannet, Odontomorus sednai), with breeding colonies in islands such as the Galapagos and Hawaii (it shares its range with more restricted hobbie species, like the Galapagos Hobbie, Adamastosula darwinensis, and the Aloha Hobbie, Adamastosula maui). Its name is derived from the white markings around its eyes (its head is black), which roughly resemble glasses. This bird, a typical sized hobbie (roughly the same size of a grannet, though with a longer wingspan, up to 4 meters) is, as the name suggests, more pelagic than its relatives, which allows it to have a larger distribution across the Pacific. Like all hobbies, its dives from the air in order to capture its prey.
Azorian Lollymawk (Pelagoptera callisto)
A common sight in the Atlantic ocean, this middle sized pseudodontorn (with a wingspan of 4.5-5.3 meters) is a typical "albatross-like" pelagornithid, soaring above the waves feeding on fish and cephalopods from the water surface, rather than diving. It also feeds on the carcasses of dead balleen squids, walducks or mosarks; being the largest seabird on the North Atlantic, it has no problems driving off smaller scavengers.
Wandering Pseudotross (Odontodiomedea exulans)
The largest living flying bird, this creature's wingspan rivals with that of Pteranodon, reaching 8 meters in length. Basically a monstrously huge version of HE's wandering albatross, this magnificient bird is as tall as a man, so most specsplorers don't dare to come very close to their nesting sites in the Austral ocean islands; Kerguelen, in particular, is a well known site. They occur in the southern seas, but occasional speciemens have been reported as north as the Galapagos. Like most pelagornithids, these birds form "life-long" bounds, though they can "divorce" if they fail to have healthy chicks too many times.
Njordornidae
The "odd pseudodontorns", they consist of two genera (plus some fossil ones, which closely resemble modern forms) that took over the pelican and skua niches. Unlike pelagornithids, these birds, which are more coastoal, have broader wings like those of avisaurs and rocs, as they use thermals to fly, rather than just oceanic winds.
Aussie Pelitooth (Ododontopelicanus antipoda)
The pelicans of Spec, pelitooths only have tooth like serrations in the upper jaw, while the lower one has the obvious pouch used to catch and carry the prey. While occuring in the same areas as HE's australian pelican, the aussie pelitooth actually resembles more HE's brown pelican, though obviously larger, with a wingspan of about 4 meters. Pelitooths, unlike pelagornithids, don't form permanent male/female couples; they usually chase after females in male/male couples, like HE's pelicans. Though, unlike them, both males raise the chicks, and so the female can mate with other males and thus have a higher chance of her genes to be transmitted to the next generation.
Hākoakoa (Njordornis australis)
With a wingspan of 3 meters, this bird is Spec's Brown Skua, occuring in Antartic and Sub-Antartic environments. Its beak serrations and size make few penguins safe; only the very big teals, and the deadly penguins of death, can safely ignore this aerial killers (the latter, though, have a taste for hākoakoan flesh). Like pelagornids, they form monogamous pairs, though they usually only last a season.
domingo, 7 de dezembro de 2008
quarta-feira, 3 de dezembro de 2008
Extinct Xenornithes
This a [horrible] essay about extinct xenornithes.
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Modern xenornithes are all classified in two orders: Xenorniformes (bunglebirds and nerds-of-paradise), and Pithecaviformes (carpos and paradise carpos). The origins of this group seem to steam from early Cretaceous †Confuciusornidae, which are very similar to modern bunglebirds; for about 65 million years, however, there was a huge gap in Xenornithe fossil record, though at least two jaws from the Maastrichian and some fragmentary remains from the Paleocene might belong to early Xenornithes. What is clear, though, is that violently reappear in the Eocene; in a space of merely 50,000 years, the Xenornithe fossil record passes from a few near fragmentary remains to thousands of nearly complete (and complete) skeletons; Messel was the site that revealed the larger quantity of Xenornithes so far. Because of the large diversity of Eocene Xenornithes, it very often assumed that the forerunners of the known clades made their first appearence in the late Cretaceous or at least in the Paleocene, but right after the thermal maximum there was literally an explosion on these birds' diversity. Such event is blamed on the effects of the thermal maximum: the expansion of the tropical rainforests, as well as a decline in Enantiornithe diversity (all post-Cretaceous opposite-birds trace their origin to merely 6 different ancestors from the Maastrichian; probably 5 or even 4, if the tweetie birds and specworld finches and parrots turn out as sister taxa, or if that such thing happens with ebergs and euavisaurs, which seem to have diverged from a single seagull/shorebird like ancestor) seemed to have been responsible for the "Eocene Explosion".
Modern Xenornithes, as obvious, made their first appearence in this epoch; the earliest bunglebird, †Eoxenavis, was already present, and the distinction between carpos and paradise carpos had already been made at the Eocene. Some extinct Xenornithes were indeed very closely related to modern carpos.
"Confuciusorniformes"
Many of the Eocene's Xenornithes are very similar to the Cretaceous Confuciusornids. Many Eocene "Confuciusornids" are often mistaken for early bunglebirds, and might in fact belong to Xenorniformes. Such genera include Aristotelornis, Awen and Messelavis.
Thanatiformes
Perhaps the most notable of Spec's Xenornithes, dead or alive, these birds are classified in two families, Thanatids and Tyrannavids. As the crown genus' name, Thanatos (literally "death" in latin), suggests, these birds are assumed to be predatory: their feet strongly resemble those of euavisaurs and those of HE's Falconiformes and Acciptriformes, and they also possess hooked beaks, sometimes with teeth-like serrations akin to those of HE's falcons. Because of their ear asymmetry, they are thought to had been nocturnal, leaving the diurnal predator niches to the first euavisaurs. Their disappearence is consistent with the disappearence of the global forests and the appearence of the first scowls, all in the beginning of the Neogene.
Thanatos
Known mainly from Europe and North America sites, some other thanatid taxa might be synonymous with it. It life, this falcon sized bird would had resembled HE's strigid owls (only with wing claws and a non-zydactyl feet), though more accurate reconstructions depict it with the facial disc of feathers in the head, which Thanatiformes appearently lacked. It has also well defined canine-like serrations on the beak. Three species are known, though only T. adamaste has been well described.
Xenotyto
A close relative of Thanatos, this bird is known mainly from North America and Europe, with fossils in South America as well. It has longer legs than its european relative, probably hinting towards a cursorial lifestyle akin to that of HE's borrowing owls, though it was more likely like HE's barn owls.
Falcostrigyx
Possibly a synonym of Thanatos, it is mainly known from Mongolia. It is almost identical to its european relative, though it lacks the canine-like serrations. Some yet to be described australian forms might belong to this genus, if it is valid.
Enantiophagus
Known exclusively from South America, it differs from other thanatids in the way it might have had a feathered facial disc like HE's owls and Spec's jungle demon. Its name (literally "opposite eater") is a refference to fossiliazed baby enantiornithes (appearently early specworld finches) found in one specimen's stomach; presumably it died before regurgitating the prey's bones in a pellet, as other thanatiformes are known to had done (we have fossil pellets).
Tyrannavis piscivora
The single specie of a single genus of a single family (all other thanatiformes belong to Thanatidae), this bird differs from its closest relatives due to the absence of the typical ear asymmetry (which suggests that it might had been diurnal), and due to its longer, more powerfull beak; in life, it would had been like a HE's osprey with wing claws. It seems to had been a fish eater, as fish scales were found on its stomach.
Enarorniformes
This clade only includes, as far as it is known, only two genera: Enarornis and Pekkalavis. The first fossil uncovered (a metatarsus) came from Finland ("Enare" means lake in sweedish, and this very first fossil was found roughly 2 miles south of lake Inari), though since then more complete remains came from other parts of Eurasia and North America. Both species are turkey sized (Pekkalavis mainly differs from having a hooked beak and a smaller hallux digit in the feet), have big, round wings, and gastroliths in the stomach; it has therefore been asumed that they occupied a niche roughly similar to the Early Cretaceous Omnivoropteryx and Sapeornis (which are unrelated to Xenornithes), as soaring omnivores.
Pithecaviformes
While obviously not extinct, carpos have some extinct relatives.
Germanocarpo
A crow sized Pithecaviforme from Europe, this bird resembles the earliest known carpo, Paleocarpo, though it is still capable of flight; however, it is phylogenetically the most basal known Pithecaviforme (and perhaps the oldest, since fragmentary remains from the late Paleocene might belong to this genus; certainly, the possible xenorthitian owners of the parrot like jaws from the late Cretaceous are related to it). Because it already had a quite parrot like beak, it seems that the less powerfull beak of the paradise carpos isn't an ancestral characteristic of this clade.
Hesperoxenornis
Probably a synonym of Germanocarpo. Known from the Americas.
Parsidiocarpopteryx
An early genus of paradise carpos, appearently still able to fly (though modern paradise carpos might had lost their ability to fly multiple times, as opposed to the true carpos, already flightless in the Eocene); fossils occur in Eurasia and North Africa, thus showing that paradise carpos weren't always restricted to Africa (some undescribed fossils also came from South America).
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Modern xenornithes are all classified in two orders: Xenorniformes (bunglebirds and nerds-of-paradise), and Pithecaviformes (carpos and paradise carpos). The origins of this group seem to steam from early Cretaceous †Confuciusornidae, which are very similar to modern bunglebirds; for about 65 million years, however, there was a huge gap in Xenornithe fossil record, though at least two jaws from the Maastrichian and some fragmentary remains from the Paleocene might belong to early Xenornithes. What is clear, though, is that violently reappear in the Eocene; in a space of merely 50,000 years, the Xenornithe fossil record passes from a few near fragmentary remains to thousands of nearly complete (and complete) skeletons; Messel was the site that revealed the larger quantity of Xenornithes so far. Because of the large diversity of Eocene Xenornithes, it very often assumed that the forerunners of the known clades made their first appearence in the late Cretaceous or at least in the Paleocene, but right after the thermal maximum there was literally an explosion on these birds' diversity. Such event is blamed on the effects of the thermal maximum: the expansion of the tropical rainforests, as well as a decline in Enantiornithe diversity (all post-Cretaceous opposite-birds trace their origin to merely 6 different ancestors from the Maastrichian; probably 5 or even 4, if the tweetie birds and specworld finches and parrots turn out as sister taxa, or if that such thing happens with ebergs and euavisaurs, which seem to have diverged from a single seagull/shorebird like ancestor) seemed to have been responsible for the "Eocene Explosion".
Modern Xenornithes, as obvious, made their first appearence in this epoch; the earliest bunglebird, †Eoxenavis, was already present, and the distinction between carpos and paradise carpos had already been made at the Eocene. Some extinct Xenornithes were indeed very closely related to modern carpos.
"Confuciusorniformes"
Many of the Eocene's Xenornithes are very similar to the Cretaceous Confuciusornids. Many Eocene "Confuciusornids" are often mistaken for early bunglebirds, and might in fact belong to Xenorniformes. Such genera include Aristotelornis, Awen and Messelavis.
Thanatiformes
Perhaps the most notable of Spec's Xenornithes, dead or alive, these birds are classified in two families, Thanatids and Tyrannavids. As the crown genus' name, Thanatos (literally "death" in latin), suggests, these birds are assumed to be predatory: their feet strongly resemble those of euavisaurs and those of HE's Falconiformes and Acciptriformes, and they also possess hooked beaks, sometimes with teeth-like serrations akin to those of HE's falcons. Because of their ear asymmetry, they are thought to had been nocturnal, leaving the diurnal predator niches to the first euavisaurs. Their disappearence is consistent with the disappearence of the global forests and the appearence of the first scowls, all in the beginning of the Neogene.
Thanatos
Known mainly from Europe and North America sites, some other thanatid taxa might be synonymous with it. It life, this falcon sized bird would had resembled HE's strigid owls (only with wing claws and a non-zydactyl feet), though more accurate reconstructions depict it with the facial disc of feathers in the head, which Thanatiformes appearently lacked. It has also well defined canine-like serrations on the beak. Three species are known, though only T. adamaste has been well described.
Xenotyto
A close relative of Thanatos, this bird is known mainly from North America and Europe, with fossils in South America as well. It has longer legs than its european relative, probably hinting towards a cursorial lifestyle akin to that of HE's borrowing owls, though it was more likely like HE's barn owls.
Falcostrigyx
Possibly a synonym of Thanatos, it is mainly known from Mongolia. It is almost identical to its european relative, though it lacks the canine-like serrations. Some yet to be described australian forms might belong to this genus, if it is valid.
Enantiophagus
Known exclusively from South America, it differs from other thanatids in the way it might have had a feathered facial disc like HE's owls and Spec's jungle demon. Its name (literally "opposite eater") is a refference to fossiliazed baby enantiornithes (appearently early specworld finches) found in one specimen's stomach; presumably it died before regurgitating the prey's bones in a pellet, as other thanatiformes are known to had done (we have fossil pellets).
Tyrannavis piscivora
The single specie of a single genus of a single family (all other thanatiformes belong to Thanatidae), this bird differs from its closest relatives due to the absence of the typical ear asymmetry (which suggests that it might had been diurnal), and due to its longer, more powerfull beak; in life, it would had been like a HE's osprey with wing claws. It seems to had been a fish eater, as fish scales were found on its stomach.
Enarorniformes
This clade only includes, as far as it is known, only two genera: Enarornis and Pekkalavis. The first fossil uncovered (a metatarsus) came from Finland ("Enare" means lake in sweedish, and this very first fossil was found roughly 2 miles south of lake Inari), though since then more complete remains came from other parts of Eurasia and North America. Both species are turkey sized (Pekkalavis mainly differs from having a hooked beak and a smaller hallux digit in the feet), have big, round wings, and gastroliths in the stomach; it has therefore been asumed that they occupied a niche roughly similar to the Early Cretaceous Omnivoropteryx and Sapeornis (which are unrelated to Xenornithes), as soaring omnivores.
Pithecaviformes
While obviously not extinct, carpos have some extinct relatives.
Germanocarpo
A crow sized Pithecaviforme from Europe, this bird resembles the earliest known carpo, Paleocarpo, though it is still capable of flight; however, it is phylogenetically the most basal known Pithecaviforme (and perhaps the oldest, since fragmentary remains from the late Paleocene might belong to this genus; certainly, the possible xenorthitian owners of the parrot like jaws from the late Cretaceous are related to it). Because it already had a quite parrot like beak, it seems that the less powerfull beak of the paradise carpos isn't an ancestral characteristic of this clade.
Hesperoxenornis
Probably a synonym of Germanocarpo. Known from the Americas.
Parsidiocarpopteryx
An early genus of paradise carpos, appearently still able to fly (though modern paradise carpos might had lost their ability to fly multiple times, as opposed to the true carpos, already flightless in the Eocene); fossils occur in Eurasia and North Africa, thus showing that paradise carpos weren't always restricted to Africa (some undescribed fossils also came from South America).
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