Talk:Paraves

Taxonomy contradiction

The infobox on this page lists Epidexipteryx as a separate group from Eumaniraptora, but its own page says it's an avialan and therefore a member of Eumaniraptora. 69.111.189.155 (talk) 02:29, 29 December 2012 (UTC)

Its position outside Eumaniraptora as recovered by Turner, Makovicky and Norell (2012) is also reported in the article Scansoriopterygidae. But yeah, it should be mentioned in its own article as well.--Macrochelys (talk) 10:01, 29 December 2012 (UTC)

That study found several different positions in and out of Paraves for that taxon, so is not definitive and will need further study to resolve. It should not be used as a basis for changing the previously accepted position of Epidexipteryx as an avian. MMartyniuk (talk) 13:31, 29 December 2012 (UTC)

Gigantism and miniaturization

>Both gigantism and miniaturization occurred within Coelurosauria...

Are there terms "gigantism" and "miniaturization" could link to? "Gigantism" links to an article about abnormally large animals in a species. Miniaturization links to manufacturing smaller and smaller versions of a tool or mechanism. Surely, there is a biological term that describes this type of evolution? Rissa, Guild of Copy Editors (talk) 02:27, 22 March 2015 (UTC)

Would Phyletic dwarfism do? Omar (talk) 03:37, 16 November 2023 (UTC)

Move material from intro

I've just moved a bunch of stuff from the intro downward. The rule is that the intro should summarise the body content - but none of this stuff was in the body. It now is, but probably needs some re-organisation. Go to it. Snori (talk) 00:29, 3 June 2015 (UTC)

What's a 'parave'?

What's an 'ave' (member of taxon 'aves')? Well it's a bird. So what's a 'parave' (member of taxon 'paraves)? Par(a)+aves: alongside birds, literally. How about "the most primitive animals that we might consider to be birds, and all of their descendants, some of which are modern birds, along with other extinct animals which were also birds, many being flighted, feathered, and having toothless beaks". A parave is a true bird. True birds arose and diversified in the latter Mesosoic era but most mesosoic birds didn't survive the K-T extinction event.

The intro is a statement of paleo-cladistics in ornithology, and would be at home in the Taxonomy section (currently called 'Classification'). I'm inclined to move it there, and fill in an expanded and readable intro that summarizes the whole article, including taxonomy and cladistics. Start with something like the above definition of paraves.

Sbalfour (talk) 05:14, 17 December 2016 (UTC)

I agree that the opening is unhelpful to ordinary readers; the article should be about the organisms placed in this group, not about cladistics. (More generally, many articles about extinct birds and bird relatives have a dogmatic tone: "birds are dinosaurs, so there". Peter coxhead (talk) 07:23, 17 December 2016 (UTC)

I'm going to take a stab at it, leave it here while I think about it, and obtain validation from seasoned ornithologist-editors.

Proposed article lead

Paraves (literally "near birds") are a clade of small (no larger than a modern macaw) bipedal omnivorous dinosaurs originating in the Jurassic period 165 million years ago (Mya) which were the first true birds. Their descendants were primitive birds and bird-like dinosaurs; among them were the predecessors of modern birds. Most of the descendants of paraves were extinguished at the Cretaceous-Paleogene extinction event (K-Pg) 66 Mya, along with all of the other dinosaurs. Around that time, birds underwent a rapid evolution and dispersal, resulting in most of the major groups of birds we know today.

The paraves were feathered and had toothed beaks or snouts (later untoothed beaks) and elongated forelimbs, possibly wings. The early paraves were unflighted, though it is believed that various groups of paraves glided, jumped, and flapped in precursor flight similar to todays flying squirrels or flying lemurs. Fully flighted birds evolved a few million years later. The iconic Archaeopteryx, a crow-size very bird-like reptile is a genus of early paraves that lived 150 Mya, and may have been the first flighted bird.

Descendants of paraves were not the first or only flighted animals, for example bats, insects and pterodactyls. Pterodactyls were non-dinosaurian flying reptiles contemporaneous with the dinosaurs and not at all related to birds, but once believed to be the predecessors of birds.

The paraves are descended from theropod ("beast foot") dinosaurs among them Tyrannosaurus rex, a group which is part of saurischian (lizard-like) dinosaurs, one of two major divisions of dinosaurs. Dinosaurs are ancient reptiles that evolved 231 Mya, before birds, mammals and humans. Many bird-like attributes had already evolved starting as long as 50 million years before the time the paraves came into existence: notably smaller body size, feathers, a fused bone in the wrist, as well as wings.

Paraves were four-toed like most perching birds, but a notable characteristic is the presence of a raised toe holding a large 'sickle claw', resulting in only two toes supporting the weight of the animal (the first or inner-most toe was reduced in size and splayed to the side or reversed), so that the bird made two-toed footprints. The functional purpose of the sickle claw has been variously attributed to climbing, or shearing or gripping prey.

Recently, a fossil of the earliest known feathered dinosaur designated Aurornis xui discovered in China was tentatively dated to 160 Mya. It is more primitive than Archaeopteryx, and may be the oldest known bird.

Unfortunately there are many basic factual errors in this proposed text. Some examples: If Paraves is taken as a clade (all descendants of a common ancestor), then many are much larger than a macaw. Paraves include the first true birds but they as a group were not the first true birds. Archaeornithes is an obsolete taxon which would be partially overlapping with Parades as used here, resulting in one sentence saying they were the first true birds and the next saying they gave rise to birds which is nonsensical. Most descendants of parades were not "extinguished" at K-Pg because there are more of their descendants alive today then there were in the Mesozoic. No species had "toothed beaks", rather teeth and beaks were variously present in various parts of the skull but did not overlap. Recent research is suggesting that early paravians took off from the ground, so the comparison to flying squirrels is not accurate. The paragraph about "pterodactlys" is weirdly out of place, and it's not worth mentioning bats, which evolved one after the first paravians. Saurischia means lizard-hipped dinosaurs, not lizard-like. The raised sickle-claw is not a universal feature of earl paravians and might have evolved two or three times or been lost in many lineages. Significance of Aurornis as the earliest paravian should be stated that way, without reference to whether or not it's a "bird", and it should be noted that several other paravians are known from the exact same age (also it's discovery is no longer "recent", being 4 years ago). Dinoguy2 (talk) 13:15, 26 December 2016 (UTC)

Wow! Dinoguy2 knows his stuff. I'll rewrite, correct, and/or delete text as necessary until it meets your standard. Thanks. Sbalfour (talk) 17:28, 26 December 2016 (UTC)

Proposed article lead, redux

Paraves (literally "near birds") are a clade of small, bipedal dinosaurs originating in the Jurassic period 165 million years ago (Mya). The group includes all birds as well as bird-like dinosaurs. All the paravian lineages except for modern birds became extinct at the Cretaceous-Paleogene extinction (K-Pg) event 66 million years ago, along with all other dinosaurs. Around that time, birds underwent a rapid evolution and dispersal, resulting in most of the major groups of birds we know today.

The paravians evolved from theropod ("beast-footed") dinosaurs, a group which is part of the saurischian ("lizard-hipped") lineage and includes such iconic members as among them Tyrannosaurus rex. Dinosaurs are archosaurian reptiles that evolved 231 years ago. Many bird-like traits had already evolved in the dinosaur lineage long before the time of the first paravians; notably, these traits include small body size, feathers, a fused bone in the wrist, as well as wings.

All paravians are feathered and have forelimbs modified into wings. Some early lineages were four-winged, with feathered airfoils on both the fore and hind limbs. Most primitive paravians had toothed snouts, but several different advanced lineages evolved beaks and lost their teeth, possibly in conjunction with a change to omnivorous or herbivorous diet. The first paravian groups were flightless, though evidence suggests that some of them glided, jumped, and flapped in precursor behavior to flight. Many later paravian groups have became secondarily flightless, and have evolved into larger species from a small ancestor. Fully flighted species evolved by the early Cretaceous period. The iconic Archaeopteryx, a crow-size bird-like reptile from the late Jurassic, may have been among the first flighted paravians.

Paravians are ancestrally four-toed, though some lineages have evolved fewer toes. A notable characteristic among some early paravian species is the presence of a raised second toe holding a large 'sickle claw', resulting in only two toes supporting the weight of the animal (the first or inner-most toe was reduced in size and splayed to the side or reversed), so that these dinosaurs made two-toed footprints. The functional purpose of the sickle claw has been variously attributed to climbing, shearing, or gripping prey.

Several bird-like dinosaur fossils discovered in China (for example, Aurornis xui and Anchiornis huxleyi) have been dated to the mid-Jurassic period, around 160 million years ago. They are both older and more primitive than Archaeopteryx, and are currently the oldest known definitive paravian remains.

I made some edits for clarity and accuracy to the text above, but otherwise it looks good! Dinoguy2 (talk) 13:49, 8 January 2017 (UTC)

Proposed new section: Origin and evolution

Need to keep this section brief and narrowly focussed on Paravians, else overlap [Origin of birds]] and Evolution of birds.

Basal Paraves were pennaceous-feathered, 'flying', arboreal, long-bony-tailed, four-winged birds. They could 'fly' (i.e. glide) from the trees down, but not from the ground up.

I propose to elaborate a new section under taxonomy (possibly raise to level 2) describing the Origin (ancestry) of paraves, and Evolution (descendants of paraves excluding modern birds, up to their K-T extinction). It's clear now in contrast to what was believed previously - that Archeopteryx burst upon the scene as a fully formed bird - that bird attributes including bipedalism, endothermy, edentulism, featheration, elongated forelimbs w/pennaceous feathers (wings) and others, evolved gradually and piecemeal over a long time, at least 50 million years predating Archaeopteryx, and possibly starting as long as 240 Ma (monofilament feathers), preceding the origin of dinosaurs. Nowhere else discusses this confluence. Likewise, nowhere else discusses the general evolution of non-avian descendants of paraves, i.e. what were originally the Archaeornithes, a disused taxon (so nothing current or meaningful discussed there). There is evidence of an adaptive radiation and evolution of basal paravians in the early Cretaceous, prior to that of the avians starting ca 95 Ma. That isn't presented anywhere, either. If not here, then where? Paraves is a purely hypothetical signpost; what we want to know is how did mostly-reptilian animals become mostly bird, and how did the non-avian bird-like lineages devolve that caused them to all go extinct?

The first dinosaurs were small bipedal possibly fuzzy or feathered predators. For some millions of years, the lineage increased in body size. Then for unknown reasons, probably ecological niche-filling adaptations, the lineage diverged: the stem lineage that eventually became birds decreased in body mass, while outgroups continued to increase in mass. This trend continued even as flighted paravians emerged, in the Troodontidae and Dromaeosauridae. A recent study shows that about 200 million years ago, theropods near the base of the avian lineage were probably in the area of 160 kg. These gave rise to the megalosaurids. By 25 million years later, that stem ancestor had shrunk to 46 kg, but it was still giving rise to lineages like the allosaurs and tyrannosaurs. Ten million years and many branches (including the maniraptors) later, the last group to split off from the birds probably weighed only 3 kg, while the first members of the paravian lineage were less than a kilogram.

"That isn't presented anywhere, either. If not here, then where?" Dinosaur or Avemetatarsalia would be a much better place, since many of the features you cite predate the advent of Paraves by a long time. Even your proposed text seems to discuss the entire evolutionary history of dinosaurs, so the main dinosaur article is where this should go. "Paraves is a purely hypothetical signpost;" As are all clades, by design. "what we want to know is how did mostly-reptilian animals become mostly bird, and how did the non-avian bird-like lineages devolve that caused them to all go extinct?" This would not be a great place to discuss the transition from "mostly reptilian" because Parades were already mostly bird! Coelurosauria might be a better place, since its the most well-known clade close to the advent of bird-like features such as complex feathers and wings. And of course there's no such thing as "devolution", that implies evolution has a direction. The non-avian paravians went extinct for the same reason everything does - too specialized to survive rapid environmental changes. Aves at the time were generalists. Dinoguy2 (talk) 13:22, 26 December 2016 (UTC)

Yeh, after thinking this over, and because another knowledgeable dino editor has already flagged this section as "messed up", I believe any extended discussion of origin and evolution of bird-likeness should move somewhere else. I do consider that Paraves are the aboriginal birds, and I still remember the day when paleontologists thought Archaeopteryx came into existance by a burst of incredibly unlikely bundled adaptations for flight (divine intervention? Oh, please!), because that's the only bird-like dinosaurian fossils we had. So I think we need to state somewhere that Paraves didn't come into existance like that; the evolutionary changes were piecemeal, the timeframe very long (~50 million years at least). I'll keep it short, maybe don't need it to be a subsection. Thanks, again. Sbalfour (talk) 17:49, 26 December 2016 (UTC)

Simplified cladogram

The existing cladogram is more concerned with cladistic detail than usefulness, and doesn't at all show how Paraves (almost a bird) relates to Aves, or to immediate sibling or predecessor taxons. For 'almost' a bird, there's a lot of mostly irrelevant stuff inbetween, most of which isn't shown in the article. I propose something like the following, either to replace or supplement the existing cladogram. It will resist mutation as cladistic boundaries change, and gives a true picture of the lineage, everything that matters. The outgroups can be defined in footnotes. They typically represent a fossil or set of fossils (detail in Fossil record section). Paleontologists tend to invent ersatz names for what otherwise would be node-based clades (like Avebrevicauda) solely to use as placeholders for a new genus/species represented by a single fossil. Every time a new fossil is found, cladograms throughout the paleontology articles need to be changed, sometimes extensively reshuffled. The outgroups are chimera, but that's ok - detailed cladistic relationships of these can be found in the articles of the ancestor taxon, or wikilinks in the footnotes. Sbalfour (talk) 00:27, 19 December 2016 (UTC)

Coelurosauria †Tyrannosaurs and others Maniraptora other Paraves siblings †Oviraptors Paraves outgroup1 †Dromaeosauridae †Troodontidae Avialae outgroup2 Euavialae outgroup3 Pygostylia outgroup4 Ornithothoraces †Enantiornithes Euornithes outgroup5 Ornithurae outgroup6 Neornithes

Stem lineage for Aves Legend: Paraves siblings=†Alvarezsauria, †Therizinosauria, outgroup1=†Scansoriopterygidae, outgroup2=†Archaeopteryx, †Aurornis, outgroup3=list outgroup4=list outgroup5=list outgroup6=list

Cladograms are the results of a data analysis. You can't simply make one that shows something different for simplicity's sake, because the truth is not simple and to do so would be to falsify the data. The cladogram in the article is the result of a peer-reivieewed analysis. Dinoguy2 (talk) 13:27, 26 December 2016 (UTC)

Tetrapterygidae problemmatical taxon

Tetrapterygidae is a family-level taxon using an invalid name, according to the ICZN, because it lacks a type genus Tetrapteryx. Not only that, but it's an apomorphy-based clade grouping taxons from several different levels. No other researchers have affirmed this.WP:primary sources, T:ONES. It appears to me to be nothing more than a proposal. Do we really want this here? Eumaniraptora and Averaptora aren't very stable either, at this time. By elaborating these here, we're more or less entering into the debate, rather than expounding fact. My original statement was "Other clade names have been coined or proposed to split off or combine outgroups immediately descendant from Paraves: Eumaniraptora, Averaptora, Deinonychosauria and Tetrapterygidae." The recent studies are in conflict; until there's consensus, I think we should stop there, with one-liner definitions.Sbalfour (talk) 00:29, 27 December 2016 (UTC)