Subject: Re: mass extinctions and technology - msg#00671

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RE: mass extinctions and technology

>Hi all, > > An old question I would like to reintroduce: > > "If human beings were to become extinct in the next 500 years due to > global warming, pestilence or other catastrophe, what if anything would > remain of our civilization to reveal us to the next super species, 65 > million years from now?" . > > I sent a standard email to 100's of paleontologists and archaeologists > (PHd's in the USA and worldwide), asking this question to try and > get some > consensus. I received approximately 60 replies. The results are as > follows. About 20 thought there would be direct evidence to reveal > us. About 30 were uncertain. About 10 thought there would be no > evidence > to reveal us. > > There seems to be no consensus in paleontology and archaeology. Perhaps no concensus, but science doesn't work by polling... :-) I find it spurious to think that the presence of a technologically advanced (and, consequently, numerically abundant) organism would have little preserved fossil record. Using our only known sample (us), let's take a look at a few aspects of our preservability: * We are abundant, and indeed within the last century are probably the most common large-bodied vertebrate species on the planet (with the possible exception of those species that we have made: i.e., the domestic critters) * We are geographically widespread and inhabit a wide variety of environments * We have a distinctive morphology which is as easily preservable as any other vertebrate In other words, we have all the attributes of an index fossil (save only the one we can't test yet: our duration on the planet!). Additionally, our remains and the remains of our technologies (i.e., trash) make their way into many of the depositional environments (i.e., future sedimentary rocks) of the world. The sediments of the Mississippi, Nile, Ganges-Brahmaputra, etc. river valleys and deltas, and even the deep sea floor, are littered with bits of our machines, our manufactured waste products, and occasional representatives of us. We have engaged in largescale transformation of the surface of the earth: the foundations of shopping malls, airports, strip mines, etc. are some rather large and distinctive trace fossils!! (Particularly the latter, as they actually enter the rock rather than merely unconsolidated sediment or soil). We have been responsible for mass extinctions, but also for the large scale homogenization of the terrestrial (and to a lesser degree aquatic) biota of the Earth; useful and pest species are conciously (or unconciously) transported by us across the planet. All these factors will make our presence exceedingly preservable. The only way that I envision our presence not being recoverable in the 10s-100s of millions of years time scale would be if, for some reason, all Holocene sediments and surfaces were somehow removed from sampling. This seems very unlikely. > Make the following assumptions: > > 1. Locatable and identifiable remains of a Pre-Human Civilization (PHC) > are mostly microscopic > > Widespread microscopic remains of PHC's may exist in the sedimentary > record. The remains may be in the form of particles, persistent organic > pollutants, trace elements, isotopes or other types. See above why this assumption is not necessary valid. However, I agree that our chemical presence is equally well-marked for the future. > 2. Given two isolated civilizations, be they isolated by time OR space, > technology will evolve along similar lines. Actually, a VERY questionable assumption, given our very small sample size. However, since our sample is all we have to go with, it is the best we can do. Additionally, check out Jared Diamond's Guns, Germs and Steel for some interesting observations about the history of our species and its technology. For example, there are good arguments to be made that the idea of writing may have only been developed twice independantly (Sumeria & Mesoamerica), and that all other writing systems were developed with the knowledge and experience that some other people were able to make marks to record information. > Common themes will prevail, with regard to the technological > progression in > isolated civilizations. This is given that many natural laws, that > constrain or direct technological advancement, would be > consistent between > the two systems. This assumption is more relevant to civilizations > separated by time, as the physical environment is more likely similar. > For example, if we consider two such earth civilizations, we might expect > to see non-sustainable utilization of the earths resources in both. Such > activity might include fossil fuel energy or mass extinction. We > might also > expect to see the development of synthetic compounds such as persistent > organic pollutants. Based on this, we have substantial evidence that no PHC ever developed coal-based technologies, as there is no sign of non-human disruption of the late Paleozoic coal deposits of the world. > It seems intuitive, that the more fundamental the technology, the more > likely it will be common to both civilizations. Whereas the more > elaborate, > or obscure a technological advance, the less likely we would see it > represented in both civilizations. > > 3. Let us assume that mass extinction and heavily industrialized > civilization are closely related. > > Let us assume the PHC would cause a gradual mass extinction, as does our > existing civilization. WHOA there!! Check your time scales! What appears to be a "gradual mass extinction" at the scales of human societies would look like an instantaneous event from the point of view of a couple of million years from now or more. In fact, it would BE what a geologist would refer to as an instantaneous event. While your hypothesis is interesting, and the tests you suggest would certainly be useful in supporing the claim of a PHC, let's not lose sight of Occam and multiply entities unnecessarily. As there are as yet no good indication of the presence of said PHCs (either their bodies or their technologies) in the fossil record, and as other physical factors (terrestrial and extraterrestrial) can reasonably be invoked for the cause of mass extinctions, then looking for PHCs at present is comprable to looking for evidence of paleo-time scale alien landings. Sure, it would be phenomenally interesting!! But I would want a lot of good additional supporting evidence before I went invoking this as a possible cause. Would make an excellent plot to a great science fiction story, though. Thomas R. Holtz, Jr. Vertebrate Paleontologist Department of Geology Director, Earth, Life & Time Program University of Maryland College Park Scholars College Park, MD 20742 http://www.geol.umd.edu/~tholtz/tholtz.htm http://www.geol.umd.edu/~jmerck/eltsite Phone: 301-405-4084 Email: tholtz@xxxxxxxxxxxx Fax (Geol): 301-314-9661 Fax (CPS-ELT): 301-405-0796

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Preliminary Discussion of Omnivoropteryx and Scansoriopteryx

Though my copy of Czerkas' book has not yet arrived, Mike Keesey was kind enough to scan me a few images of these new controversial taxa. Here are my preliminary opinions- Omnivoropteryx sinousaorum This is apparently only shown in X-rays, which allow limited detail to be discerned. Description will emphasize comparison to Caudipteryx and Sapeornis, which Ford and Holtz have posited affinities with respectively. The skull is thus complete, but sutures are almost impossible to locate. It does actually resemble Caudipteryx in gross morphology. The snout is shorter and the external nares located more anteriorly. The snout's ventral margin is lower than the posterior skull's, the orbit is extremely large, and the nares are angled sharply anteroventrally. Those are the only details available. The mandible is slender, with a strongly decurved dentary that curves upward at the very tip. There seems to be a long and low external mandibular fenestra, but this is much more posteriorly placed than in Caudipteryx. A cervical and over ten dorsal vertebrae are preserved, along with dorsal ribs. Caudipteryx and other enigmosaurs have ten or less dorsal vertebrae, while non-pygostylian birds had 12-13. It's unfortunate the tail was not preserved. The scapula is extremely useful in identifying this taxon. The blade is sinuously curved, decreases in width posteriorly, and seemingly has no dorsally projecting acromion process. It is extremely similar to Rahonavis in these features, but differs from oviraptorosaurs like Caudipteryx. That of Sapeornis is difficult to compare due to its presevation in lateral view. The humerus is very elongate and strongly curved. It resembles that of Sapeornis in the extent the two can be compared, which is basically restricted to the outline. It just may have the characteristic distal spike on the deltopectoral crest of the latter genus, though the X-ray makes this unclear. Humeri of oviraptorosaurs (eg. Caudipteryx, Microvenator) are more stout and straight (without the strong distal curve). The radius and ulna are also similar to Rahonavis- the ulna is strongly bowed, while the radius is very slender and ends in an abrupt expansion. Caudipteryx lacks the disparity in width between the antibrachial elements, and has no marked distal radial expansion. Metacarpal I is extremely short (~1/7 of mcII), like Sapeornis, Jeholornis and other basal birds, but unlike oviraptorosaurs. Phalanx I-1 is slender and bowed, only half the length of metacarpal II. The reduction is characteristic of derived avians, and the morphology is most comparable to Sapeornis (and to a lesser extent Jeholornis). The whole first digit does not pass the tip of metacarpal II, like Sapeornis, Jibeinia and ornithothoracines. Caudipteryx differs in these characters, with a longer and stouter phalanx I-1, and a first digit that reaches past phalanx II-1. Phalanx II-I might have a distal expansion like Sapeornis, pygostylians and Sinornithosaurus. Phalanx II-2 is shorter than II-1, like Jibeinia and ornithithoracines (but unlike Sapeornis). Phalanx II-2 is bowed and slender distally, as in avians and approached in some eumaniraptorans (eg. Sinornithosaurus). Caudipteryx lacks a distal expansion of II-1, has a longer II-2 than II-1, and has a more robust less bowed II-2. The third metacarpal is closely appressed to the second, like Caudipteryx and Sapeornis, but unlike Jeholornis. I see no indication of phalanges, but Caudipteryx and Sapeornis both have two on that digit in any case. The pubes are preserved in oblique anterior view. The pubic symphysis was reduced (~1/3 of pubic length), like Sapeornis, Jeholornis and pygostylians (Caudipteryx and other oviraptorosaurs have a ratio of ~1/2). The pubic shafts are bent posteriorly a little distal to midlength, as in some eumaniraptorans (eg. Archaeopteryx, Bambiraptor, Sinornithosaurus), but unlike the forward curving pubic shafts of oviraptorosaurs. Finally, the pubic boot projects completely (or almost completely) posteriorly, as in eumaniraptorans. The pubic boot morphology is closest to Archaeopteryx, but differs from enigmosaurs, which have predominantly anteriorly projecting pubic boots. Ilial and possible ischial remains cannot be discerned well. The bowed femora, tibiae and slender fibulae are too poorly figured to describe useful morphologies. The metatarsus is not arctometatarsalian, and no fifth metatarsal is visible. The metatarsals are said to be unfused. The first digit appears reversed, and phalanx I-1 is extremely long and bowed. The latter is much longer than non-avian theropods, Rahonavis, Archaeopteryx, confuciusornithids and most Mesozoic ornithothoracines. It suggests perching abilities were well developed. Phalanx II-2 is subequal to II-1, as in other eumaniraptorans, but unlike oviraptorosaurs. The second digit shows no predatory specializations. The distal phalanges of digits III and IV are also elongate compared to the penultimate phalanges, unlike Caudipteryx and most non-avians (Rahonavis as well). Phylogenetic Relationships- The only oviraptorosaur-like characters are the short snout, ventrally displaced premaxilla and anterior maxilla, decurved dentary and elongate external mandibular fenestra. The first is common in basal birds, especially Jeholornis. The third is also found in Jaholornis, while the third is seen in confuciusornithids. The second character is not known in eumaniraptorans. Characters found in basal avians, but not oviraptorosaurs are- more than ten dorsal vertebrae, scapula decreases in wifth distally, acromion does not project dorsally(?), distal scapular shaft curved to be concave dorsally, distal humerus strongly curved anteriorly/laterally, radius about 1/2 of ulnar width, distal radius abruptly expanded, metacarpal I ~1/7 of metacarpal II length, phalanx I-1 ~1/2 of metacarpal II length, phalanx I-1 slender, phalanx II-2 distally expanded(?), phalanx II-2 shorter than phalanx II-1, pubic symphysis ~1/3 pubic length, pubic shafts bent posteriorly around midlength, pubic boot projects mostly posteriorly, metatarsal V absent(?), elongate metatarsal I, phalanx II-2 subequal in length to II-1, distal phalanges of pedal digits III and IV elongate compared to penultimate phalanges. While a few of these might be expected in a convergently volant oviraptorosaur, many have no particular relation to flight. So Omnivoropteryx is not a volant oviraptorosaur, but is a eumaniraptoran instead. Exactly where within Eumaniraptora Omnivoropteryx should be placed is a difficult question, as the topology around the avian base is uncertain. It is less derived than ornithothoracines based on- scapula not distally tapered; manual unguals not reduced; phalanx II-2 not as shortened; pubic symphysis not as reduced. It shares features with several taxa of basal birds, notably Rahonavis, Sapeornis, Jeholornis and to a lesser extent Archaeopteryx, confuciusornithids and Jibeinia. Thus is will probably end up slightly more derived than Archaeopteryx, but less than pygostylians. Scansoriopteryx heilmanni Scansoriopteryx is very similar to Epidendrosaurus- The specimens are similar in size, Scansoriopteryx being on average 14% larger (elements 5-22% larger). The frontals are nearly identical, strongly triangular with a V-shaped notch between them posteriorly. There appears to be a posterior process on the parietal of Scansoriopteryx, as in Epidendrosaurus. The scapula is strongly expanded distally. The coracoid has a unique C-shape, approached most closely by Archaeopteryx, but more robust. The humeri both have proximally placed deltopectoral crests and are similar in morphology. The metacarpals and manual phalanges have similar and derived proportions, with metcarpal III longest, digit III hypertrophied and phalanges III-1 and III-2 not reduced as in most theropods. Oddly, both specimens seem to have an astragalus missing the ascending process aligned with the tibial axis on a distal edge of the latter. The metatarsi are very similar, with III slightly constricted in the middle, but expanding again proximally to equal its distal width. Metatarsal I is articulated distally in both. The pedal phalanx proportions are similar as well. I can find the following differences- The parietal is shorter compared to the frontal in Scansoriopteryx. The sclerotic ring of Scansoriopteryx is made of about 14 separate elements, unlike the solid ring in Epidendrosaurus. There is no "articular" projecting dorsally in Epidendrosaurus' mandible. The distal scapular edge is perpendicular to the blade axis in Scansoriopteryx. The ulna of Epidendrosaurus is bowed and the radius looks thinner in comparison. The first manual ungual is much larger than the second in Epidendrosaurus, but not in Scansoriopteryx. The "articular" of Epidendrosaurus is better seen as a displaced coronoid, and the distal scapular edge would not be expected to fully ossify in juveniles. It's possible the parietals of Scansoriopteryx are not completely preserved, or have overlapped the frontals. I cannot explain the other differences. I don't believe they warrent generic separation, but perhaps at species level (especially if the two formations they were found in are not contemporaneous). Phylogenetic Relationships- I believe Scansoriopteryx is a basal avialan. This is based on the following lines of evidence. The jugal is slender suborbitally (as in birds), with a posteriorly placed and strongly sloped dorsal process (resembling Bambiraptor most). The quadratojugal has a large posterior process, making it T-shaped. This process is larger than birds, being similar to basal deinonychosaurs like Bambiraptor and Sinornithosaurus. The ventral postorbital process is extremely thin, showing it was nearly absent (but still contacted the jugal). The triangular frontals are similar to eumaniraptorans, while the posterior parietal process is like that of Sinornithosaurus. Assuming the Epidendrosaurus mandible is correctly referred, the teeth lack serrations and are mediolaterally thick, like avians. Although the strong and medially curved dentary symphysis is like oviraptorosaurs, the posterodorsal dentary process is not elongate and the external mandibular fenestra is not as enlarged as oviraptorosaurs. The ninth and more posterior chevrons are strongly flattened dorsoventrally (as in eumaniraptorans), but not as elongate as Jeholornis or dromaeosaurs. They are nearly identical to those in Archaeopteryx and Rahonavis. The caudals with flattened chevrons also elongate to over twice the length of the first caudal centrum, similar to dromaeosaurs, but less than Archaeopteryx, Jeholornis and Rahonavis. Prezygopophyses are elongate, extending to half the proceeding central length. This is much less than dromaeosaurs, but is a bit more than Jaholornis, and much more than Archaeopteryx and Rahonavis. The coracoid is elongate (but not strut-like) and curved posteriorly, being most similar to Archaeopteryx. The ilium has an extremely elongate preacetabular process, like Rahonavis and avians. It has a slight ventral expansion, like Rahonavis and Unenlagia. The postacetabular process on the other hand, is strongly reduced, as in Rahonavis and Aves. The pubis is mesopubic as preserved, like Archaeopteryx, Jeholornis and especially Unenlagia and Rahonavis. The pubic boot is reduced, as in troodontids and Sinornithosaurus. The distally placed and seemingly reversed hallux is similar to avians. Pedal phalanx II-2 is elongate relative to II-1, as in eumaniraptorans. There are several characters distinctly unlike avialans and basal eumaniraptorans (distally expanded scapula, elongate ischium, ischium strongly posteriorly concave, no dorsal ischial processes), but I feel these are overwealmed by the other characters noted above. Regarding integument- there are tuberculate scales preserved with the distal tail of Scansoriopteryx, and elongate ulnar feathers/filaments (~1.5 times ulnar length). There is also filamentous integument associated with the skull, pelvis and proximal tail. I don't see why adult Scansoriopteryx could not potentially fly. Those who want pictures of Omnivoropteryx (skull, feet, and whole specimen) and Scansoriopteryx (skull, whole specimen) e-mail me offlist. Mickey Mortimer

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RE: mass extinctions and technology

> From: owner-dinosaur@xxxxxxx [mailto:owner-dinosaur@xxxxxxx]On Behalf Of > Mark Harvey > > You have got to start somewhere. To my knowledge, the organic > environmental geochemistry of extinction boundary sediments has > never been > examined. Not so: organic (carbon isotope and other) geochemisty has been examined for at least the K/T, and to a lesser degree some of the other events. > You are forgetting the dimension of time. We may be abundant and > widespread, but for how long? One of the explanations given for SETI > (search for extraterrestrial intelligence) NOT receiving any alien > broadcasts is that civilizations capable of radio technology > don't last long. While this would be true for the radio record (Fermi's paradox does indeed neglect the time component) this would not necessarily hold for the geological record. We would not have to recover ALL the places humans occupied (or dropped their trash), just a couple, in order to recognize they we were here. > >We have engaged in largescale transformation of the surface of the earth: > >the foundations of shopping malls, airports, strip mines, etc. are some > >rather large and distinctive trace fossils!! (Particularly the > latter, as > >they actually enter the rock rather than merely unconsolidated > sediment or > >soil). > > Shopping malls and airports are relics of the last 100 years. > This gives > them a very short window of opportunity for preservation. How > much of the > pyramids will remain in even another 10,000 years? Quite a bit of the basal stones, and a lot of the quarries. (In fact, the primary evidence that would remain would, as in archaeology, be primarily the unintended stuff: trash dumps, strip mines, houses and cars buried by floods of the Mississippi or Hawaiian lava flows, etc.) Also, what they lack in history shopping malls and the like make up for in number, thereby increasing their chance of recoverability. > >We have been responsible for mass extinctions, but also for the > large scale > >homogenization of the terrestrial (and to a lesser degree > aquatic) biota of > >the Earth; useful and pest species are conciously (or unconciously) > >transported by us across the planet. > > This homogenization could be obscured by an associated mass extinction / > climate change = sea level instability. However, we don't have to resort to the theoretical here. We a) have a terrestrial fossil record and b) see no evidence at present there IS taxonomic homogenization save for the Pangaean Late Triassic (and even here there is regionalization). Both terrestrial and marine paleobiogeography are topics of some interest, and the expected results of a presence of a PHC have yet to manifest themselves. > >All these factors will make our presence exceedingly preservable. > > I think limited visible (> 1mm) evidence of our civilization may survive, > but a combination of factors might render the evidence hidden, > unrecognizable, or simply unrecognized. ie. scarcity, burial, erosion, > metamorphosis or confusion with contemporary trash. I would argue against most of these. Scarcity. This can always be used as an ad hoc defense for PHCs. However, given our current sample and given some theoretical basis (of an organism capable of transforming some substantial part of the biomass to its own use) we would expect that a PHC would easily be capable of population increases in the exponential mode, as we have done. Burial, erosion, metamorphism. If we are talking about PHCs evolving in the later Phanerozoic (say the mid-Paleozoic onward) then the only remains that would be lost to metamorphism would be through deep burial or those on (at the time) continental margins, which have since been turned into mountain ranges by collisions or lost through subductions. Nevertheless, we still have substantial records of parts of the Earth throughtout this interval. Confusion with contemporary trash. This would be unlikely when you crack open a Permian shale and find the trash therein! Remember that other materials with similar preservability to garbage (i.e., animal parts, leaves, twigs, pollen & spores, etc.) are routinely recovered from ancient sedimentary rocks. If they weren't, there would be no science of paleontology! > >The only > >way that I envision our presence not being recoverable in the 10s-100s of > >millions of years time scale would be if, for some reason, all Holocene > >sediments and surfaces were somehow removed from sampling. This > seems very > >unlikely. > > > It would certainly by recoverable, but you would have to be > looking for the > right tracers in the right environment. I would argue not, particularly if the traces are physical rather than chemical. That is, we can easily recognize a worm burrow or Paleocastor (ancient beaver) burrow when we come across them; an ancient strip or tunnel mine should be much more recognizable given its scale, and eminently more preservable. > Good point, but maybe such disruption has been metamorphosed. Also, I do > not know the estimated depletion of earths late Paleozoic coal > deposits. If we have only scratched the surface of these deposits, then > this would reduce the chance of the same deposit being mined twice. Actually, there are pretty good estimates for their distribution, abundance, and resource size (as you can imagine, there are many vested interests in getting this information!). True, some of these resources were obviously lost during erosion of the Appalachians and other regions. Nevertheless, there do not appear to be big erosional surfaces that one would expect if a coal-based technology utilized substantial portions of this limited resource. > I totally agree with you . It takes an impact scenario these days to get > the public interested in mass extinction (see the first five minutes of > "Armageddon" where Bruce Willis clubs golf balls at the Greenpeace > protesters from his oil platform). Try to tell someone that the earth is > warming by .5 celcius every 10 years and they will yawn and turn up the > sport on the television. Indeed... > No-one was invoking an impact hypothesis until the boundary sediment's > inorganic geochemistry was checked for by Walter Alvarez. For the K/T, no, although it had been suggested long ago for the Late Devonian extinction. Furthermore, the Alvarez team wasn't even investigating the K/T extinction event, despite popular claims to the contrary. They were instead simply trying to find out how much time was represented by the boundary clay, using what they hoped would be a time-averaged stable preservable tracer. Unfortunately, the assumption of time-averaging was a bit skewed in this instance... :-) > I think an alien landing is far less likely to leave globally ubiquitous > geochemical footprint. Having said that, NASA will probably get > around to > checking for these compounds on Mars before anyone bothers to check > earth. I think the real reason we are slow to check these old > sediments ( > from the perspective of organic environmental geochemistry) is that: > > 1. The technology has only been around to do so for 20 years True. > 2. We think we are pretty special (see the dark ages when we literally > thought the univers revolved around us) See rather the points I suggested previously: i.e., without additional supporting evidence one might not run the costly analyses. That being said, there has been a LOT of examinations of organic and inorganic material at the K/T boundary, and some (but less so) at other boundaries. Thomas R. Holtz, Jr. Vertebrate Paleontologist Department of Geology Director, Earth, Life & Time Program University of Maryland College Park Scholars College Park, MD 20742 http://www.geol.umd.edu/~tholtz/tholtz.htm http://www.geol.umd.edu/~jmerck/eltsite Phone: 301-405-4084 Email: tholtz@xxxxxxxxxxxx Fax (Geol): 301-314-9661 Fax (CPS-ELT): 301-405-0796

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just for fun

Maybe you already knew about, however, I've found a site on the net with (mostly) dinosaurs origami the URL is http://www.cs.uu.nl/~hansb/d.origami/dinosaurs.html it's funny, and also pterosaurs, Archie and other critters are featured. Cheers, Silvio Renesto _ The voice from the lake then asked "which is the strangest thing of all?" Judisthira replied "Every day men see other men die, they see the chariots with the corpses and the fires, yet they keep living as they were immortals, this is the strangest thing of all" (from Mahabharatha) Silvio Renesto Dipartimento di Scienze della Terra Università degli Studi di Milano Via Mangiagalli 34 I 20133 Milano Italy phone +39-02-50315511 fax +39-02-50315494 e-mail: renesto@xxxxxxxxxxxxxxxxxxx Silvio.Renesto@xxxxxxxx have a look at our Triassic website at http://users.unimi.it/vertpal/index.htm