The Mini Dinosaurs from the Harz Mountains

FiReaNGeL writes "When unusually small dinosaur fossils were found in a quarry on the northern edge of the Harz Mountains in 1998, it was initially assumed that these were the remains of a group of young dinosaurs. This was a fallacy, as the Bonn palaeontologist, Dr. Martin Sander, recently discovered. At a maximum estimated weight of one tonne, they were only a fiftieth the weight of their closest relatives, the brachiosaurs, and thus by far the smallest of the giant dinosaurs which have ever been found."

Comments

Small Giants

[crazyjeremy]

Heh heh... he said "smallest of the giant dinosaurs"

Re:Small Giants

[Lectrik]

Heh heh... he said "smallest of the giant dinosaurs"

's a bit like being the most civilized monkey in the zoo...

Re:Small Giants

[NickFortune]

Shush you - or I'll set my minature giant space hamster on you.

Go for the eyes, Boo! GO FOR THE EYES!"

Re:Small Giants

[Whiney Mac Fanboy]

's a bit like being the most civilized monkey in the zoo...

Or the smartest member of congress?

Re:Small Giants

[datafr0g]

's a bit like being the most civilized monkey in the zoo...

Or an insightful comment on slashdot.

:)

Re:Small Giants

[tbone1]

This reminds me of comedian Jeff Rothpan's bit about his unltra-cheap father taking him to a really cut-rate circus:

And now, huuuuuge midgets!

Re:Small Giants

[stonecypher]

I dunno, Gorilla Grodd and the Ultra-Humanite do a pretty good job of it.

Mini-people

[HexRei]

Interestingly...

This all fits in with the discovery which the scientific journal Nature reported on last year: on Flores also the 18,000-year-old bones of a 'dwarf' human. This 'Flores hobbit' was only one metre tall.

This may fit in elegantly, but last I heard (maybe even on slashdot) this discovery was now believed to be a normal human with a disease of some sort.

Re:Mini-people

[afaik_ianal]

This may fit in elegantly, but last I heard (maybe even on slashdot) this discovery was now believed to be a normal human with a disease of some sort.

It's still disputed. Wikipedia has a short summary of the 2 opinions here: http://en.wikipedia.org/wiki/Homo_floresiensis#A_n ew_species.3F

The thing I don't understand about the hypothesis that the fossil is actually a diseased human, is that they found partial fossils of 8 other individuals, which I assume were consistent with the near-complete fossil being debated. What are the chances of them all having this extremely rare defect, given that it shortens life expectancy, and severely limits normal brain function?

Re:Mini-people

[Ponzicar]

They've since uncovered several more skeletons, all of the same stature.

Re:Mini-people

[stonecypher]

Wait. Did you just ask what the chances were that a genetic defect would become prevalent in a tiny isolated group of individuals? After just a few generations it's near-100%. That's why inbreeding is bad. This is what created the pygmies and various other dwarf and midget populations throughout the world.

Granted it's not nessecarily the same defect, but the idea that a small group of people is somehow immune to disease strikes me as silly.

Re:Mini-people

[khallow]

The thing I don't understand about the hypothesis that the fossil is actually a diseased human, is that they found partial fossils of 8 other individuals, which I assume were consistent with the near-complete fossil being debated. What are the chances of them all having this extremely rare defect, given that it shortens life expectancy, and severely limits normal brain function?

First, as pointed out in the other reply to your post, it's not unlikely in small populations for this to occur. Second, neither shortened life expectancy nor severely limited brain function precludes survival. For example, virtually all animals would have severely limited brain function when compared to humans. They survive quite well however. And almost as few animals live as long as humans do. This doesn't hamper their ability to propagate. Finally, let us note that these humans aren't around any more. Ie, they didn't survive. So it is consistent with what we currently know, even if you're correct.

Re:Mini-people

[afaik_ianal]

That's why inbreeding is bad. This is what created the pygmies and various other dwarf and midget populations throughout the world.

I wouldn't mind seeing a reference on a claim like that. I call BS. See http://www.discover.com/issues/may-92/features/aqu estionofsize42/

In summary, it is believed to have been a slow evolutionary process. Some of the factors they believe select a smaller size are: temperature (pygmy populations have evolved almost exclusively around the equator - being smaller makes it easier to disipate heat); landscape (they tend to live next to or in dense forest, and being small makes it easier to move between branches etc).

And from WP:
"Pygmies are smaller because in their early teens they do not experience the growth spurt normal in most other humans. This is an environmental adaptation, smaller bodies have evolved independently in non-human species in response to isolation on small islands or dense forest environments."

Re:Mini-people

[afaik_ianal]

Second, neither shortened life expectancy nor severely limited brain function precludes survival.

This is not the average run-of-the-mill genetic deformity. People with severe microcephaly are extremely unlikely to survive beyond childhood without care. As children, they are unable to feed. As they begin to grow, they experience seizures, fail to develop motor skills, are unable to learn, and can become paralysed. (Basically, the brain continues to try and grow as normal, but the head doesn't). I can handle a microcephalic child surviving to adulthood even tens of thousands of years ago. I don't buy them then going on to care for their own microcephalic child. [Disclaimer: IANAD]

Re:Mini-people

[khallow]

This is not the average run-of-the-mill genetic deformity. People with severe microcephaly are extremely unlikely to survive beyond childhood without care. As children, they are unable to feed. As they begin to grow, they experience seizures, fail to develop motor skills, are unable to learn, and can become paralysed. (Basically, the brain continues to try and grow as normal, but the head doesn't). I can handle a microcephalic child surviving to adulthood even tens of thousands of years ago. I don't buy them then going on to care for their own microcephalic child. [Disclaimer: IANAD]

Very good point. However, let us also recall that genetically people were different back then. And it is possible (though I consider it unlikely) that the genetic defect that leads to microcephaly might manifest in a much less harmful way to that population.

Re:Mini-people

[stonecypher]

I wouldn't mind seeing a reference on a claim like that. I call BS. See http://www.discover.com/issues/may-92/features/aqu estionofsize42/

You should read the article you cited, where it begins to discuss the endocrinological differences between pygmies and average people, their extremely low birth size, their lack of an adolescent growth spurt, and so on. It seems your article actually supports me. Actually, essentially every reference I find which is newer than 1980 supports me. Mercedes de Onis is responsible for a great many studies you can look into if you're interested, but the canonical reference is TJ Merimee's paper in the New England Journal of Medicine, NEJM issue 316, pp906-91. That's in 1987, if you actually intend to look it up, and want to call your library to make sure they have it first. That paper discusses insulin-like growth factor (you can read more about that on the internet as IGF, not ILGF.) Studies show that the Bantu, Ituri, Efe and Mbuti - the peoples we refer to as pygmies from the Congo forests of Zaire - stop growing at between 10 and 12 years of age, have no postpuberty endocrine phase at all (the 13-15 year old omg how tall did you get last summer thing.)

More detailed studies have since been made, though they're not as easy to read. Another reasonable paper is RC Bailey's, from Annals of Human Biology, issue 18 pp113-20, which is from 1991. That paper focuses specifically on the near-total lack of IGF-1, which is the most common reason for non-dysplasic dwarfism (that is, the stuff that isn't about your skeleton binding early.) The group of conditions circling around IGF-1, IGTD and similar chemicals is known as GHD. In the pygmy peoples there's also been a demonstrated lack of ICF-I by Renaldo Martorel, and there are several statistical studies which suggest (we're not sure yet) a resistance to Partial Growth Hormone, presumably due to damage in GHBP's ectodomain. Alternate isolated peoples show problems in other parts of the growth sequence, such as the Mountain Ok, Aeta and Mamanwa, who are lacking Growth Hormone Binding Protien but who do not show the resistance to GH.

A more important paper, but one which is almost impossibly for a layperson to read, is E.Z. Tronick S.A. Winn's paper in the Journal of Pediatric Developmental Behavior, issue 13, pp421-4, from 1992. That paper addresses the complete lack of other problems, most notably reduced vision, mental retardation, brittle skeleton or fragile tendon disorders which would be expected if the lack of growth was based on dietary fault. In fact, the only dietary health problem commonly attributed to the pygmies is hypoglycemia, which is suspected to be largely due to the major and frequently unreliable usage of honey in their diet and trade relationships with surrounding peoples.

Another paper from 1992, Zhou Xianjin's paper to Nature in issue 376, pp771-4, suggests that the Efe may in fact have two seperate kinds of pervasive dwarfism, a flaw in the nuclear scaffolding HmGI-c and HmGI(y), which is critical during embryogenic cycle dependant phosphorylation. Awesomely, Nature actually gives the references for their papers online, which saves me a lot of retyping.

You can also look up the Mountain Ok from Papua New Guinea, who show deficiencies in GHRhR. Unfortunately, the Kongkandji, Indindji and Barbaram aboriginal peoples of Australia are essentially extinct, so we have no idea what kept them small; medical science, working largely from photographs, suggests thanatophoric or diastrophic dysplasia, both of which are genetic disorders with a high recurrence in spontaneous mutation, due to the damage being near the end of the appropr

It's hotly contested.

[jd]

Near the site of the "hobbits", they have found fairly advanced stone tools and stone arrowheads. People so acutely affected by the suggested dwarfing disorder would have inhibited brain function and certainly could not have developed an advanced technology or operated it. This makes it somewhere between unlikely to impossible for all of the people on the island to have been mentally afflicted. This leaves only two options - either these remains are of extremely unusual people, and were in a community of more typical hominids, and it's pure chance that no remains of these typical hominids have been found, OR they genuinely were a miniaturized subcategory of hominid that were not impaired at all, so there is no contradiction involved with there being an advanced technology.

The debate has likely intensified even further with recent genetic studies of Neanderthals, using mtDNA extracted from the teeth. This is because the mtDNA shows vastly greater variation in early Neanderthal genetic makeup than had ever been expected. So much so that all prior studies are now considered grossly inadequate, as they only examined a hundred or so base pairs, considering the rest to be essentially identical. If genetic diversity in early hominids in general was as great as genetic diversity in early Neanderthals is believed to have been, then the probability of there having been a natural experiment in hobbits is considerably greater.

There is, however, one outstanding problem that has NOT been resolved. Dwarfism on islands is common with reptiles. Reptiles do NOT do islands well. However, mammals on islands tend towards giantism - Amblyrhiza Inundata (a giant rat the size of a grizzly) being an excellent example. Birds, although descended from reptiles, also seem to do well on islands - the Moa (a flightless bird that was 13 feet tall) and the Haast Eagle (the largest eagle that ever lived, with a wingspan of 14 feet), both from New Zealand, being good examples. This is because mammals scale well and therefore lose very little by being large, even when resources are scarce. Reptiles don't scale so well, so there is a loss of efficiency in being large. No big deal on a large enough land mass, but on an island, it's a major problem.

Humans, because they are potentially much better at cooperating, are capable of planning and storing, and are able to access a much wider range of foods over a much greater range of environments, should (based on knowledge of other island-based mammals) scale up on islands extremely well, and should only shrink where conflict is greatest, which would typically be a continent. It's hard to say if this is the case, as humans have always been amazingly mobile, but my gut feeling is that you'll find more very tall people on or around islands than you will in the middle of continents. This creates a problem for the hobbits, though. Mammals shrink when being able to run is a far greater survival trait than being able to gather more. On an island, there is very little to run from and almost nowhere to run to. There should, therefore, be no advantage to them being that small and therefore no reason for such a trait to be selected.

I think it likely that the hobbits are indeed a new branch of hominids, but without a good, solid explanation for why they would be small, the theory will never be acceptable to any evolutionary scientist worth a damn, no matter how much they want it to be true, simply because it runs counter to what we know about mammals on islands. Answering that one question will probably quell a lot of the more skeptical scientists, too. A mechanism that ties things together and presents a coherent picture is more acceptable than an extrapolation, no matter how many fossils it is from.

Re:It's hotly contested.

[sumdumass]

How do we explain pigme people in africa? And what is to say these hobbit people originated on the island. It could be very well be that they came ot the island after fleeing from somewere else. As evolution placed the genes in pigmes, it could be the same with the hobbit people. Once it is there, it stays until watered down by outside influences just like the pigme people in africa.

Could it be that we just don't have enough fossil or other records to even prove our current theories as fact. Sure everything points to it being this or that but what if we are missing a very large portion of the story.

Re:It's hotly contested.

[Anonymous Coward]

Also don't forget the dwarf woolly mammoths that inhabited Wrangel island until a few thousand years ago (well in to the current interglacial).

http://en.wikipedia.org/wiki/Dwarf_mammoths

Clearly there are multiple factors at work that affect dwarfism or gigantism. It's not possible to predict the effects of living on an island for any particular kind of animal without a lot more information. This other information might include, size of island, nutritional requirements, habitat, population dynamics, behavior, climate, other animals (predators and competitors for resources), topography, behavior, and probably much, much, more.

NOTE: IANAEB (I am not an evolutionary biologist).

Re:It's hotly contested.

[RockModeNick]

and things do not always go as typical - komodo monitors are from an island.

Re:It's hotly contested.

[callistra.moonshadow]

There are many theories running rampant about the so-called Hobbits, from misidentification to the reduced brain hypothesis. Many pressures in an isolated environment can create enough genetic pressure to lead to odd physical changes. Examples are twin studies of Andes Mountains dwelling children. When separated, one twin staying in the higher elevations and the other growing up at sea level researchers have noted drastic differences in the physical morphology. These observations hold true even though the monozygotic twins are genetically identical. The Andes-dwelling child had a large barrel chest and was shorter. The child living at or near seal level was not barrel-chested and taller. Most creatures within the animal kingdom have within their very genetic code a certain level of plasticity that we've seen demonstrated again and again as in the example above. It is not that surprising that there might have been some recessive gene that was expressed in an isolated population. It may not have been due to brain-reduction, but simply local pressures. Until they can actually identify some kind of smoking gun that can state with pretty good clarity that they can prove that these individuals didn't make the toolkit discovered, I'm more open to the possibilities.

Re:It's hotly contested.

[Anonymous Coward]

Interestingly enough an Adam Brumm from the Australian National University has a different take than you. He says that the tools are actually very simple and the skills to make such tools had been developed on the island for over 800,000 years.

It is amazing how many different opinions there are on the same facts:-)

reference: http://news.bbc.co.uk/1/hi/sci/tech/5021214.stm

Re:It's hotly contested.

[KlomDark]

"Advanced stone tools" - isn't that right up there with 'huge midgets'?

Re:It's hotly contested.

[khallow]

There is, however, one outstanding problem that has NOT been resolved. Dwarfism on islands is common with reptiles. Reptiles do NOT do islands well. However, mammals on islands tend towards giantism - Amblyrhiza Inundata (a giant rat the size of a grizzly) being an excellent example. Birds, although descended from reptiles, also seem to do well on islands - the Moa (a flightless bird that was 13 feet tall) and the Haast Eagle (the largest eagle that ever lived, with a wingspan of 14 feet), both from New Zealand, being good examples. This is because mammals scale well and therefore lose very little by being large, even when resources are scarce. Reptiles don't scale so well, so there is a loss of efficiency in being large. No big deal on a large enough land mass, but on an island, it's a major problem.

I disagree with this claim. First, the claim that reptiles "don't do islands well" seems absurd. The Galopagos tortoise and Komodo Dragon lizard seem excellent counterexamples. And there's a number of examples of dwarfism in mammalian species (another example is Key Deer).

My take is that it depends on the available food supply and whether something already occupies the niche. So if some rodents make their way to a plentiful island with no other large land animals, then some of them will evolve to become large animals and occupy that niche. Similarly, if a population of large animals is stranded on an island with a small food supply, then either it will die out or evolve to a smaller size. There's no reason this couldn't happen to humans.

Re:It's hotly contested.

[captainClassLoader]

Sounds right to me. Take the rocky Shetland Islands between the Scottish mainland and Norway - They seem to be a natural miniaturization lab, due to scarce resources - In TFA, they mention the miniaturization of deer brought over from the mainland to the Shetlands, and Shetland ponies, and Shetland sheep, herded by Shetland Sheepdogs (my breed of choice) are all well-known smaller variants of larger animals from elsewhere.

Re:It's hotly contested.

[stonecypher]

This is a common misunderstanding in the mechanisms underlying natural selection. It is not the case that there's just one direction that things inevitably go, or even in fact that there's a definitive pressure applied by a given type of environment. It is often the case that several contradictory pressures are applied at once, and in many cases a species branches to fulfill both of them.

In fact, it's worth noting that all five of Earth's five biggest reptiles are in the setting that you suggest that they do not do well - the Crocodile Monitor from Papua New Guinea, the Komodo Dragon/Monitor Lizard from the Komodo Islands, Varanus Gigentis which lives on the islands around the coasts of Australia and New Zealand, the Goanna from Kakadu (also an island orbiting Australia) and the Water Monitor from Sumatra (the Nile Monitor is bigger than the Water Monitor, but they swim the oceans - they've been seen in Florida, Norway and Madagascar - so nobody knows where they're from, and locational pressure isn't an issue for them.) For that matter, the Butaan is in the Phillipines, and the Butaan is the only enormous tree lizard (also the only enormous herbivorous lizard) we're even aware of. And then there's Godzilla and Ghidra from Japan, Dark L'tzash "Dick Cheney" Sztsalit from Atlantis, and so on.

It is critically important to remember that speciation and trait selection are fundamentally stochaistic processes - they're _random_ , and in small populations there isn't enough buffer to clear out the mistakes. Sometimes an adaptation occurs not because of pressure, but the adaptation is so fundamentally different that it causes the ecosystem to change around it (the introduction of free oxygen through photosynthesis is the most dramatic example, but you see this gappen a lot when predators' targets are moved up and down the food chain, too.) Hell, sometimes an adaptation in Species A is a force for change in Species B. The oft-reported bit about the color of Rooks in London when industry happened, and made white birds easier to see than black birds, is frequently not followed through: there was a species of falcon which moved entirely away from brightness sight and towards motion sight, and the behavior of the rooks changed to made fewer and sharper turns to compensate.

This notion of "efficiency" isn't really that big of an issue to the reptiles; if it was, they wouldn't gorge and squat the way they do, which is tremendously inefficient (great cats do it too, except in the desert.) It is suspected that the reason some lizards shrink is to hide more effectively in an island where there isn't much room to hide. That explains neatly why it doesn't happen to the lizards that manage to stay at the top of the food chain; they just have no reason to hide in the first place. This is nicely seen in the Blackthroat and Red Acanthurus monitors, both who are from the same part of Indonesia - the Blackthroat got a thicker skin and a stronger jaw, making it the bad boy on the block, but the Red got a hide that looks like the local underbrush, shrank and got a brief turbo boost like crocodiles have.

I think it likely that the hobbits are indeed a new branch of hominids, but without a good, solid explanation for why they would be small, the theory will never be acceptable to any evolutionary scientist worth a damn, no matter how much they want it to be true

Yeah, um, wrong. Genetic historians know that not everything happens for a reason; it's a question of survival. We didn't evolve for spina bifida or kleinfelter's syndrome; it just happened. Sometimes those random things are good - eyeballs. Sometimes they're bad - mongolism. Sometimes they're a mixed bag - sickle cell anemia, which though it causes potentially fatal episodic shock, confers significant resistance to malaria, which before medicine was a pretty big win. Give those people another 50,000 years in the wild, and they'll probably develop a modified sickle cell which still fights the malaria but which doesn't clog the capillar

Re:It's hotly contested.

[jd]

If he didn't say something else, it would hardly be hotly contested, would it? :) Besides, even when I was at University, Professors were forever disagreeing with me. Maybe it's something they're paid to do. :)

I would point out an obvious flaw in his logic, though - in order for something to be under development for 800,000 years (as opposed to merely being used for 800,000 years), you should see signs of progress. That's obvious, right? Well, typically what constitutes progress with a stone tool is the ability to produce a more controlled shape by reducing the minimum flake size you can produce. Stylizing tools (the "Clovis Point" being an example) can only happen once you're able to work at a fine enough level for such styles to be meaningful. Obviously, however, learning more effective styles is itself progress, but it is progress that can only occur after learning how to work the material to the necessary degree.

A "simple" stone tool implies no styling at all and only minimal progress in refining how to work the material. So, the question would be how many steps would it take for the improvement in workmanship to no longer be considered minimal? (Since a fine-grained reduction requires a fine-grained technique, initial steps would necessarily be coarse-grained. The rate of change of reduction in flake size would crudely approximate to a hyperbolic curve.) On the flip-side, how infrequent can improvements be made and still call things "progress" as opposed to "in use"?

Ultimately, improvements would seem to need to be frequent enough that, over the course of 800,000 years, it is simply no longer possible to call the tools "simple", except in relation to - say - later Iron Age or (in the case of this Professor) modern, industrialized, Western civilizations. Either that, or the progress WAS extremely limited, in which case the improvements could NOT be considered evidence of 800,000 years of progress. The professor can't have it both ways - it's either simple OR it's 800,000 years of R&D, it can't be both. The published data seems (to me) to support the conclusion that it was advanced enough to be beyond a culture of severely mentally impaired humans, no matter how long the society had.

(Early Stone Age cultures in Europe developed tools extremely slowly and most experts I've read on the subject usually state quite clearly that, for most of that time, technology was stagnant - to the point where it has been seriously debated as to whether early stone-age Europeans might have had a genetic defect leading to learning disabilities and/or severely crippled long-term memories.)

Re:It's hotly contested.

[jd]

The pygmies of Africa are relatively easy, using the conventional wisdom (ie: that mammals shrink on continents) - it's much harder to explain why there are so many taller people in Africa. Africa's a big place, with land ranging from deserts to thick jungle. Food is not a problem there, but avoiding becoming food is. The problem with a continent is that you have massive biodiversity, which means that there is a much higher likelihood of there being something capable of consuming, say, a human. Mammals have typically survived in such cases by shrinking, so as to be harder to see and to be better able to evade. It's not universal, but it's common enough to be considered a rule-of-thumb.

(Individual survival is also much more important, as there is a far lower probability for any given individual to survive and therefore far lower probability for a particular set of genes to carry on. In relatively isolated environments, such as islands, it is possible for communities of animals to develop a sense of cooperation, as there is no significant pressure on the individual EXCEPT from the community, and no real pressure on the community EXCEPT by reducing the size of the gene pool it can draw from. In an environment where scale is unlimited and individuals are under great stress, communities can afford to lose individuals - a large community won't be affected at all and small communities won't risk resources they don't have. Evolution will select for efficiency of the masses on islands, without regard to the efficiency of the individual, and will select for the efficiency of the individual in continents, without regard to the efficiency of groups.)

Re:It's hotly contested.

[jd]

Definitely maybe, but only always sometimes.

Ok, ok, I'll be serious for a second - it depends on what you define "advanced" as being relative to. If you're talking in the context of stone tools, then your lowest level is a lump of rock picked up from the ground, and your highest level is the finest the stone will fracture repeatably combined with the best possible shaping for the purpose of the tool. If you picture this as an X-Y graph, where (0,0) is the lump of rock and the ideal is (M,N), draw two diagonal lines where each starts on the Y axis, ends on the X axis and do not cross. Anything between (0,0) and that first diagonal is "primitive". Anything between the first diagonal and the second is "middling". Anything between the second diagonal and (M,N) is advanced.

Canarysaurus

[Bob Cat - NYMPHS]

Someone was going to say it. Get it? Hartz Mountain Inc. sells bird seed? Little dinosaurs? No? I'll go back to Digg now...

Re:Canarysaurus

[gurutc]

Bravo! I was looking for the joke that you found. You ciphered it.

But didn't you mean Canarydactyl?

Re:Canarysaurus

[Bob Cat - NYMPHS]

No, if I were going to MINE the joke further, I would have referred to the "Pollydactyl". How about that? A cat + bird pun! (for people not from around here - a polydactyl cat is one with extra toes. Common in New England and some other places. Mrow.)

Re:Canarysaurus

[sharkey]

Lady, I'm going to tell you the same thing I told everybody else: I'm sorry if your dog went blind, but your beef is with Harz Mountain, not with me.

Dinosaur Racing

[monkaduck]

Let's get that cloning going and get some dinosaur racing going on! C'mon, what's cooler -- betting the ponies or betting the 'saurs?

Oxymoron (love this word!)

[Nuffsaid]

Instead of the oxymoron "smallest giant", they should have said "smallest member of a family of dinosaurs whose other members are known to be giants, like the Brachiosaurus".

Re:Oxymoron (love this word!)

[Valdrax]

Now that is a textbook example of pendantry. Never say in 2 words what could be said in 18.
You do realize that everyone knew that's what they meant, right, Mr. Rosetta Stone?

Re:Oxymoron (love this word!)

[Nuffsaid]

Now that is a textbook example of pendantry. Never say in 2 words what could be said in 18.

Thank you. I always strive to excel.

Miniatures

[sciencecneisc]

I like the image of an elephant the size of a St. Bernard as the article referred to (Komodo Dragon food, it said).

Re:Miniatures

[tverbeek]

I like the image of an elephant the size of a St. Bernard

Might I suggest you go shopping for a tapir?

Re:Miniatures

[sciencecneisc]

Cute but as far as a Tapir, "Their closest relatives are the other odd-toed ungulates: horses and rhinoceroses." (from the link)

Re:Miniatures

[tverbeek]

Yes, but they look like cute little elephants. :)

ObUnits

[Scarblac]

From TFA: "Their cousins, by contrast, were up to 45 metres long and weighed in at 80 tonnes - as much as a small town of over 1,000 inhabitants."

I don't understand. How many Volkswagen Beetles is that?

Re:ObUnits

[Anonymous Coward]

How many Volkswagen Beetles is that?

About two and a half footballs fields long, or roughly half the thickness of a human hair.

'Conspiracy' theory

[Netochka]

Anyone ever notice how as you go further and further back in history animals get bigger and bigger compared to their present day counterparts? Like, you go back a little while and you have stuff like mastodons, saber tooth tigers, etc... Then you go back farther and you have stuff like dinosaurs... Trilobites are just like huge bugs... Doesn't anyone else find it weird, like maybe the bones are expanding as time passes or something? Anyways, I don't actually think this is true, I'm just randomly rambling, being stupid.

Re:'Conspiracy' theory

[Anonymous Coward]

Not all trilobites are particularly large. Most, in fact, are about the size of today's arthropods. The main reason arthropods never get particularly big is that if they were much bigger than they are, their bodies wouldn't be able to hold their own weight. (When size doubles, strength increases by a square, but mass increases by a cube)

Re:'Conspiracy' theory

[MichaelSmith]

Anyone ever notice how as you go further and further back in history animals get bigger and bigger compared to their present day counterparts?

• Big stuff lasts longer in the ground and is easier to see when you go digging
• Human beings kill the biggest animals around for food, this being the most efficent way to get dinner. Over time big things become extinct.

Re:'Conspiracy' theory

[khallow]

My take is that a lot of it depended on the dominant plant life and carbon dioxide levels. Modern plants are more resistant to large herbivores. They also efficiently extract CO2 from the atmosphere (grasses in particular use a particularly efficient photosynthesis cycle). In addition, we're in the midst of a long period of ice ages (warm periods like now are infrequent).

What I think this means, is that the modern environment is more hostile to huge plant growth and large herbivores than the eras of the distant past.

Re:'Conspiracy' theory

[RsG]

That doesn't hold up for much of history. The Triassic era didn't have large dinosaurs, but the following eras (Jurrasic and Cretaceous) did. The dinosaurs got bigger as time went on, not smaller - Tyranosaurs were the last and largest of their line. There are plenty of examples of the reverse happening (large dinosaurs getting smaller, see Utah Raptors shrinking down to Deinonocus (Sp?) and Trodon), but there isn't a strong trend in that direction. It was the mass extinction at the end that got all the large animals out of the picture, which is to be expected in a global die off.

Trilobites aren't the best example either - they are not just large bugs, they're a whole different group. There are examples of massive insects from earlier eras (massive meaning much bigger than today, though still not large when compared to a mammal), but those were probably dead ends - insects have a maximum size due to their exoskeletons, and being larger is a disadvantage for them. And if you want examples of big invertebrates today, squids and octopuses come to mind, as do crustaceans like crabs and lobsters.

As for the ice age mammals (mastodons, saber tooth cats and the like), there's a very good reason they got bigger when it got colder. Larger animals have a greater volume relative to their surface area, since surface area increases by the sqaure, and volume by the cube (^2 vs. ^3). Surface area to volume determines the rate of heat loss to the surrounding environment - larger animals retain heat better than small ones. They grew to mammoth size when the ice age made heat retention vital, and they died off or shrunk when the ice age ended.

Re:'Conspiracy' theory

[Anonymous Coward]

Larger animals are more heat efficient. They lose a smaller percentage of their heat energy through thier skin. As we're now, apparently, heading towards a new ice age (Which Global warming might help to prevent. Everybody, buy SUVs!!), you can look forward to a reversal of this getting smaller trend.

Re:'Conspiracy' theory

[Whitemice]

There are lots of well known reasons for this. Most notably the size of animals, especially insects, varies depending upon the amount of O2 in the atmosphere. The composition of the earth's atmosphere has varied significantly over time.

BTW, this is the real flaw with all time travel movies. If you bopped back to the age of the dinosours, you'd probably be dead within minutes as you might as well have jumped to a different planet. And dinosours's cloned back to like today would have to live in big bubbles with elevated oxygen levels [fire hazard!].

Picture of Mini Dinosaur

[Spy Handler]

Scientist's speculation of what the mini dinosaur might have looked like - picture

Re:Picture of Mini Dinosaur

[FirienFirien]

403 forbidden unless you reload the page? Tut tut...

Candy?

[Anonymous Coward]

Did "mini dinosaurs" make anyone else think of chocolate-filled candy? Or is posting this anonymously a good idea?

Mammoths did try a smaller form

[ianscot]

Populations of wooly mammoths did indeed evolve into the "pygmy" mammoth.

Pygmy populations derived from elephants or mammoths are known from several locations throughout the world, including the islands of Malta and Sicily in the Mediterranean, several islands in southeast Asia, and Wrangel Island in the Arctic

Nova did a nice program on the questions about the little hairy elephants a few years ago, I think concentrating on the ones on Wrangel.

Re:Mammoths did try a smaller form

[sciencecneisc]

There's a PBS article on the evolution of pgymy animals and humanls. http://www.pbs.org/wgbh/nova/sciencenow/3209/01-di amond.html

Not just on Wrangel island, either

[ianscot]

"Pygmy" or dwarf mammoths have been found on islands from all over:

Pygmy populations derived from elephants or mammoths are known from several locations throughout the world, including the islands of Malta and Sicily in the Mediterranean, several islands in southeast Asia, and Wrangel Island in the Arctic.

Nova did a nice little show about the Wrangel ones, if I remember right.

hurm...

[Churla]

Small enough to have been a pet it seems.

Did they note the suspicious remains of a Father-son-daughter "routine expedition" nearby? Any three fingered lizard men? Strange pylon with crysatls inside?

Smallest sauropod, most likely

[J.R. Random]

The article was slashdotted so I couldn't read it and this post is the usual Slashdot speculation. The smallest dinosaurs known were about the size of chicken. So I presume they meant this beast is the smallest known sauropod http://en.wikipedia.org/wiki/Sauropod. Most sauropods were humungous, so a one ton adult would be very small.