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The only real restriction on a holotype is that it has to be a specimen that preserves enough features for it to be diagnostic from other related animals. This is dependent on what kind of animal you have, for example vertebra are highly diagnostic in sauropods. Ultimately the holotype will be the specimen for which all other specimens of the species are compared, and because of all these factors there isn't really a universal standard for declaring them.

That being said, some people do tend to stretch what could be reasonably considered diagnostic, and we have to be careful about trace fossils. For example, isolated teeth and feathers which are a part of the body, but which have limited diagnostic capabilities (teeth less so). Distinctive trace fossils should be named not as species, but as ichnospecies until a specimen can definitively but a body to the feature.

But wouldn't one think that there should have been a universal standard, or at least a serious attempt to make one, by now?

Hi. I'm Nathanoraptor and I'm new here. Dinosaur breeding habits have been a bit of an interest of mine, in particular, those of sauropods.

From what I've read, there's a real quandary about the topic of sauropod parental care, because, on the one hand, there are theoretical arguments (e.g. the vast size difference between adults and juveniles and the need to move around a lot) and observational factors (a lack of tiny and giant sauropods found together) that argue against any extended form of post-hatching parental care (please note the emphasis on post-hatching).

However, in opposition, there are phylogenetic arguments in support for parental care, as parental care for at least several weeks is present in crocs and birds, and there is plenty of reason to think that it is not a derived trait, but one that is present in Archosauria ancestrally. Based on that, I'd imagine that there's little reason to think sauropods as a group were somehow different to all their relatives in this regard.

Also, there are probably tamphonomic arguments; I know fairly little about geology, but I'd guess that sedimentary systems are highly unlikely to simultaneous preserve large sauropod bones and tiny baby ones in the same depositional settings and that adult sauropods would make tracks on substrates that baby sauropods - or you and I - could not.

I read Myers and Fiorillo's paper on the topic and, from that, I think claims of segregated sauropod herds have to be tested for the possibility of taphonomic size filtering. Please note, however, I'm no geologist and my knowledge of the fossil sites in question is poor; is there any evidence that the juvenile sauropods in question died at the same time?

My personal opinion? I would presume that, since sauropods were a diverse bunch, that there were many different strategies that were employed by the many species, just like the many kinds of child rearing/abandoning behaviour in birds and reptiles today. However, it’s my belief that all dinosaurs practiced some form of parental care; people who think this sort of thing is unique to neornithine birds and mammals need their heads examined. (Of course, this could be anthropomorphic bias; I suffer from that. A lot.)

I'd like for see what others think of this question; is it supported by evidence or am I just suffering from anthropomorphic bias?

First of all, welcome. We hope you enjoy it here.

As for sauropod parental care. Given what we know about how birds and many reptiles-noticeably the crocodile family-do have parental care while other reptiles don't, it's safe to say that some sauropods did have parental care but others didn't. If sauropods had the strategy of sea turtles, then we'd be finding far more skeletons of young sauropods. But given how fast they grew and how few sauropod babies have been found, those support the evidence of sauropod parenting.

If crested theropods grew larger then those without, then how did Gigantoraptor get so...gigantic when compared to the other oviraptoriods? Could it be that the one that was found was a crestless female and the male which, if sexual dimorphism applies here, has yet to be found?

Nathanoraptor wrote:

However, in opposition, there are phylogenetic arguments in support for parental care, as parental care for at least several weeks is present in crocs and birds, and there is plenty of reason to think that it is not a derived trait, but one that is present in Archosauria ancestrally. Based on that, I'd imagine that there's little reason to think sauropods as a group were somehow different to all their relatives in this regard.

Pre-hatching parental care? Probably. Post-hatching parental care? Probably not. Thing is, "bracketing is only a rough guide" used to make predictions that can be tested by finding more fossils. See the Naish/Barrett quote for a good example of that. In this case, the prediction is not supported by the fossils, especially those fossils described in Curry Rogers et al. 2016 ( http://science.sciencemag.org/content/352/6284/450 ). If you can't read the paper itself, Switek's "World’s Largest Dinosaurs Were Born Ready to Roam" is a good summary ( http://news.nationalgeographic.com/2016/04/160421-baby-dinosaur-titanosaur-fossil-independent/ ).

Nathanoraptor wrote:

My personal opinion? I would presume that, since sauropods were a diverse bunch, that there were many different strategies that were employed by the many species, just like the many kinds of child rearing/abandoning behaviour in birds and reptiles today. However, it’s my belief that all dinosaurs practiced some form of parental care;

That's pretty misleading given that sauropods aren't nearly as diverse as the entirety of living reptiles (avian or otherwise). Yes, some trackways & bone beds show segregated herds, while others show mixed herds, but even in the latter, the smallest individuals are "over one third adult size" (See the highlighted paragraph: https://books.google.com/books?id=9BPIRx-OpRMC&pg=PA248&dq=%22over+one+third+adult+size%22&hl=en&sa=X&ved=0ahUKEwjYzZLiz7jQAhUo8IMKHeu0B8wQ6AEIHTAA#v=onepage&q=%22over%20one%20third%20adult%20size%22&f=false ). This is probably for good reason (See "DAY 11": http://isismasshiro.deviantart.com/art/Dinosaur-challenge-2-394645655 ).

Rhedosaurus wrote:

Given what we know about how birds and many reptiles-noticeably the crocodile family-do have parental care while other reptiles don't,

Actually, to quote Naish/Barrett (See Dinosaurs: How They Lived and Evolved), "bonds between babies and their parents are also seen in several lizard groups. Even turtles of one species (the giant South American river turtle) use noises to guide their newly hatched babies on migration journeys."

Rhedosaurus wrote:

If sauropods had the strategy of sea turtles, then we'd be finding far more skeletons of young sauropods. But given how fast they grew and how few sauropod babies have been found, those support the evidence of sauropod parenting.

That's pretty misleading given that "There are some inherent biases in the fossil record such that some things tend to preserve more often than you would expect by chance and others are much more rare. One of the major biases is against young vertebrate animals since being small they are harder to find, and as they are still growing their bones contain more cartilage and so are less likely to preserve well" ( http://dinosaurs-world.com/News/Beautiful-baby-dinosaur-delights-palaeontologists.html ).

Quoting Naish/Barrett (See Dinosaurs: How They Lived and Evolved):

Quote :

Within saurischians, crops are unknown other than in birds. A peculiar swelling in the neck region that's been termed acrop is preserved in a mummified specimen of the hadrosaur Brachylophosaurus. If this really is a crop, it shows that at least some ornithischians evolved a crop independently of the one seen in birds–a reminder that bracketing is only a rough guide to the anatomy of extinct groups. And for all our predictions from bracketing, the possibility exists that other dinosaur groups evolved their own crops or crop-like structures, or their own gizzard-like organs.

does anyone know around what time they figured out Spinosaurus is what it is? like, when did it stop being portrayed as a sailed carnosaur and as a new type of theropod?

Oshronosaurus wrote:

does anyone know around what time they figured out Spinosaurus is what it is? like, when did it stop being portrayed as a sailed carnosaur and as a new type of theropod?

IIRC, it was the mid-late 1990's, around the time that Suchomimus was discovered. That and fragmentary Spinosaurus remains, which may still be semi-debated if it's really Spinosaurus or not, was also found in the late 1990's.

thanks very much, Rhedo  i wanted to know for a project where the original fossil isn't destroyed

Oshronosaurus wrote:

thanks very much, Rhedo  i wanted to know for a project where the original fossil isn't destroyed

No problem. By the way, I forgot to mention something. The discovery of Baryonyx in the 1980's should also be mentioned because since the holotype was remarkably complete-70% complete-that it remains the gold standard of spinosaur fossil remains.

JD-man wrote:

Pre-hatching parental care? Probably. Post-hatching parental care? Probably not. Thing is, "bracketing is only a rough guide" used to make predictions that can tested by finding more fossils. See the Naish/Barrett quote for a good example of that. In this case, the prediction is not supported by the fossils, especially those fossils described in Curry Rogers et al. 2016 ( http://science.sciencemag.org/content/352/6284/450 ). If you can't read the paper itself, Switek's "World’s Largest Dinosaurs Were Born Ready to Roam" is a good summary ( http://news.nationalgeographic.com/2016/04/160421-baby-dinosaur-titanosaur-fossil-independent/ ).

Almost every kind of parental care has been found in almost every other group of dinosaur; anyone who tries to say that this sort of thing is unique to neornithines needs their heads examined. There's abundant evidence of parental feeding in theropods (e.g. Allosaurus and Troodon) and prosauropods (e.g. Massospondylus). And, about pre-hatching parental care... isn't it commonly agreed that there was some form of nest guarding at Auca Mahuevo? I think Scott Sampson believes there was; I remember reading a book by him which stated that there was.

Please note, I rather carefully stated as a group; I wasn't asking if they all did it (there's evidence some didn't; e.g. the titanosaur that buried its eggs in South America). I was merely asking if there's a possibility that some did. Whilst the idea of extensive, elephant-type parental care (e.g. a Land Before Time scenario) comes off to me as ridiculous, I'd guess some sauropods, say, guarded their offspring through different growth phases (as alligators do today), with the offspring perfectly capable of feeding themselves.

JD-man wrote:

Actually, to quote Naish/Barrett (See Dinosaurs: How They Lived and Evolved), "bonds between babies and their parents are also seen in several lizard groups. Even turtles of one species (the giant South American river turtle) use noises to guide their newly hatched babies on migration journeys."

But you don't see lizards setting up creches (ostriches), arranging multi-generational nest provisioning (crows) or guarding offspring through different growth phases (alligators). Yes, some non-archosaurian reptiles practice parental care; but archosaurs are the ones that do it most extensively. However... is this just my mammal bias talking?

Nathanoraptor wrote:

Almost every kind of parental care has been found in almost every other group of dinosaur; anyone who tries to say that this sort of thing is unique to neornithines needs their heads examined. There's abundant evidence of parental feeding in theropods (e.g. Allosaurus and Troodon) and prosauropods (e.g. Massospondylus). And, about pre-hatching parental care... isn't it commonly agreed that there was some form of nest guarding at Auca Mahuevo? I think Scott Sampson believes there was; I remember reading a book by him which stated that there was.

I think you're confused. You specifically asked about parental care in sauropods & I answered accordingly. I clearly didn't say anything about parental care in other non-bird dinos.

Nathanoraptor wrote:

Please note, I rather carefully stated as a group; I wasn't asking if they all did it (there's evidence some didn't; e.g. the titanosaur that buried its eggs in South America). I was merely asking if there's a possibility that some did.

& I answered accordingly.

Nathanoraptor wrote:

Whilst the idea of extensive, elephant-type parental care (e.g. a Land Before Time scenario) comes off to me as ridiculous, I'd guess some sauropods, say, guarded their offspring through different growth phases (as alligators do today), with the offspring perfectly capable of feeding themselves.

By doing so, you'd be ignoring the aforementioned fossils showing that, unlike alligators, baby sauropods looked like miniature adults & didn't join adults until they were "over one third adult size". In other words, baby sauropods were superprecocial. This is like megapodes (which have pre-hatching parental care, but not post-hatching parental care).

Nathanoraptor wrote:

But you don't see lizards setting up creches (ostriches), arranging multi-generational nest provisioning (crows) or guarding offspring through different growth phases (alligators). Yes, some non-archosaurian reptiles practice parental care; but archosaurs are the ones that do it most extensively. However... is this just my mammal bias talking?

Again, I think you're confused. I was clearly responding to Rhedosaurus, not you, correcting his claim that non-archosaurian reptiles lack parental care.

JD-man wrote:

By doing so, you'd be ignoring the aforementioned fossils showing that, unlike alligators, baby sauropods looked like miniature adults & didn't join adults until they were "over one third adult size". In other words, baby sauropods were superprecocial. This is like megapodes (which have pre-hatching parental care, but not post-hatching parental care).

In my defence, I've never been anything but upfront as to the fact I came to these conclusions based on idle speculation. In fact, I came to my conclusions based on a single passage from the Scott Sampson book Dinosaur Odyssey (which didn't talk about Auca Mahuevo in any particular detail and which I have almost certainly misremembered) and stuff about modern-day animals; in particular, alligators and ratites. In fact, when I first posted it, I pretty much stated that the conclusion I came to was utter speculation and was not supported by any kind of evidence whatsoever, except for some (very amateur) phylogenetic bracketing.

Nathanoraptor wrote:

My personal opinion? I would presume that, since sauropods were a diverse bunch, that there were many different strategies that were employed by the many species, just like the many kinds of child rearing/abandoning behaviour in birds and reptiles today. However, it’s my belief that all dinosaurs practiced some form of parental care; people who think this sort of thing is unique to neornithine birds and mammals need their heads examined. (Of course, this could be anthropomorphic bias; I suffer from that. A lot.)

I wasn't acting like I had fossil evidence that sauropods showed alligator-style parental care, I was speculating that MAYBE some of them did; and, given the evidence for two very diverse reproductive strategies in one group, I'd say there's a minor possibility. Given the evidence that some showed pre-hatching parental care, I just made a speculative leap that, maybe, some species stuck around after the eggs hatched. Please be aware of that.

Nathanoraptor wrote:

In my defence, I've never been anything but upfront as to the fact I came to these conclusions based on idle speculation. In fact, I came to my conclusions based on a single passage from the Scott Sampson book Dinosaur Odyssey (which didn't talk about Auca Mahuevo in any particular detail and which I have almost certainly misremembered) and stuff about modern-day animals; in particular, alligators and ratites. In fact, when I first posted it, I pretty much stated that the conclusion I came to was utter speculation and was not supported by any kind of evidence whatsoever, except for some (very amateur) phylogenetic bracketing.

My problem wasn't w/the "idle speculation", but w/repeating said speculation in response to the fossils showing otherwise. In any case, I think we both misunderstood each other. The important thing is that we understand each other now. Also, I know what passage you're referring to (See the highlighted paragraph: https://books.google.com/books?id=RDq5Szn7afoC&pg=PA171&dq=%22example+growing+evidence%22&hl=en&sa=X&ved=0ahUKEwiS4sG6tsTQAhUBXiYKHXmkCg8Q6AEIIzAB#v=onepage&q=%22example%20growing%20evidence%22&f=false ).

aside from Dinotopia, were there ever any hypothetical reconstructions of what Deinocheirus looked like before it was determined to be an ornithomimid?

Oshronosaurus wrote:

aside from Dinotopia, were there ever any hypothetical reconstructions of what Deinocheirus looked like before it was determined to be an ornithomimid?

I do remember seeing a drawing of a hypothetical Deinocheirus in an old book my library had. The book was released some time in the 1990's and it looked a like the new Schleich Herrerasaurus toy. I don't remember the name of the book and my library most likely got rid of it in a book sale. That's the best I can do for now. JD-man might know the book that I'm talking about.

How agile and fast was Triceratops? Would it be on par with something like a rhinoceros or less?

tigris115 wrote:

How agile and fast was Triceratops? Would it be on par with something like a rhinoceros or less?

That's a basically accurate comparison. The rhino may be more agile, but Triceratops would be faster via larger legs and thus larger leg muscles.

How accurate are these?

Spoiler:

tigris115 wrote:

How accurate are these?

Spoiler:

The toe claws on the back legs need to be shorter but those one the front look good to me.

How about the ceratopsian foot

What are the two projections that look more like flaps? I've never seen those on any artworks or film.

I just saw Scott Hartman's new Stegosaurus. What would the proportions of other species such as armatus and ungulatus be?

tigris115 wrote:

How about the ceratopsian foot

Looks good to me.

tigris115 wrote:

I just saw Scott Hartman's new Stegosaurus. What would the proportions of other species such as armatus and ungulatus be?

Armatus was always considered to be slightly shorter and Ungulatus might be the same as Stenops.

So if someone wanted to make true to life theropod noises, what would be the best ingredients? I assume the bellows and hisses of crocodilians along with some material from birds like ducks and ratites.

tigris115 wrote:

So if someone wanted to make true to life theropod noises, what would be the best ingredients? I assume the bellows and hisses of crocodilians along with some material from birds like ducks and ratites.

That and whatever noises that Komodo Dragons make as well.

Another thing. I keep seeing posts that dinosaurs were limited to the sounds ducks make. Is there a source on this that isn't LCD clickbait?

tigris115 wrote:

How agile and fast was Triceratops? Would it be on par with something like a rhinoceros or less?

See ~37:00-43:00: https://www.dailymotion.com/video/x1stnyi_the-truth-about-killer-dinosaurs-part-1-documentary_tv

tigris115 wrote:

I just saw Scott Hartman's new Stegosaurus. What would the proportions of other species such as armatus and ungulatus be?

http://dinogoss.blogspot.com/2015/02/the-evolving-view-of-stegosaurus.html

tigris115 wrote:

So if someone wanted to make true to life theropod noises, what would be the best ingredients? I assume the bellows and hisses of crocodilians along with some material from birds like ducks and ratites.

https://news.utexas.edu/2016/10/12/oldest-known-squawk-box-reveals-dinosaurs-likely-didn-t-sing

Could a theropod like a tyrannosaur or carnosaur have curled its lips like a cat

What is the resting position of an Allosaurus' arms? Like, where in between a tyrannosaur and a raptor?