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  • Extinct Reptiles » Dinosaurs
  • Prehistoric Planet vs. Jurassic World. Different Receptions to Fictional Dinosaurs

    In the past few weeks we have seen the introduction of two major additions to dinosaur media. Both come from well-established franchises, but only one of these is getting lambasted by the online paleo community. Why is that?

    More specifically, why has Jurassic World: Dominion received a mix of resignation and revulsion whereas Prehistoric Planet has garnered near universal praise.

    I mean, they both portray fictional dinosaurs?

    Continue reading  Post ID 12222


  • Archives of the Dinosaur Mailing List (DML)

    Here lies the DML. Long live the DML

    [Editors note: See update on the archive below]

    In the field of vertebrate paleontology and associated paleophilia, the Dinosaur Mailing List (DML) was an invaluable source of information and networking opportunities. For many—including myself—the DML was a formative experience.

    Started back in late 1993/1994 at the University of Pennsylvania, the list initially ran internally with individuals on the list exchanging e-mails back and forth. Then, a few months later, the Cleveland Museum of Natural History agreed to host an archive of these e-mails, creating the now venerable Dinosaur Mailing List Archive. In its heyday, the DML would readily see an influx of more than 100 e-mails a day, covering everything from pack-hunting in theropods to the latest buzz on yet to be published fossils.

    Sadly, over the years and with the rise of social media, the list has fallen into disarray with fewer practicing paleontologists (and people in general) using it. As of this writing the DML sees a handful (1–5) e-mails a day with almost all of them being links to recently released papers and associated news articles (courtesy of the ever diligent Ben Creisler). While the present version of the list is but a shell of its former self it is the immense history of the archive that matters. 27 years of correspondence from various paleontologists throwing around ideas and challenging hypotheses. More than just offering a fascinating glimpse into the past, the DML archive has proven influential enough to even get cited in publication (e.g., Witton and Habib 2010).

    Unfortunately, earlier this year the Dinosaur Mailing List suddenly disappeared from its former location (dml.cmnh.org). Their host, the Cleveland Museum of Natural History, could no longer afford to maintain the archive on the site, forcing it to shut down. DML owner and listserv moderator, Mickey Rowe, attempted to find another host but to no avail. Thus, in late summer 2021 the DML archive officially disappeared from the internet.

    Thankfully, through diligent efforts from Nick Gardner and others, a copy of the archive, prior to shutdown, was obtained from Rowe and distributed freely to anyone willing to host the archives. The hope is that with enough redundant backups out there the archive should never disappear again.

    So, I’m doing my part. The DML Archives from April 1994 to May 2021 can now be accessed on the Reptipage.

    The new archive link can be accessed here: https://reptilis.net/DML/dinosaur.html

    You will also find a menu link at the top of the blog.

    We are still waiting to see where the new archive of the DML will land (for now, no e-mails are being archived). Hopefully, the DML will continue to find a home somewhere. If not, and this is the end of an era, this mirror will be one of the many headstones for this once illustrious interaction of amateurs and professionals.

    Major Update: The University of Southern California has picked up the mantle and started archiving new messages from the DML. 

    https://mymaillists.usc.edu/sympa/info/dinosaur-l

    However, one must be a member of the Dinosaur Mailing List to access the archive. 

    Thanks to Mary Kirkaldy and Ben Creisler for the following information on how to properly get access to the new DML archive (see instructions below).

    To join the DML, you will first need to send a message to sympa@mymaillists.usc.edu from the address that you want to use to subscribe to the list.

    In the subject line, put: subscribe dinosaur-l First Name Last Name.

    Change “First Name Last Name” to your name or the name you want to use.

    Subscription is free.

    The next step is to access information about your subscription to the dinosaur mailing list. Go to: https://mymaillists.usc.edu/sympa

    The first time you visit the site, click on: “First login?” at the upper left of the page.

    Enter your e-mail address and click the “Request first password” button. The site will e-mail you a message with a link.

    Clicking that link will take you back to the site with a page asking you to enter a password twice.

    Once you are logged in, any lists you are subscribed to will appear in a pane on the left. Click on “dinosaur-l” to access your subscription options.

    You can also type “dinosaur” in the Search List on the left. It should bring up the DML main page. From there, click on Archive on the left. It should open and allow you to choose a month.

    If you would like to learn about your subscription options and how to change them, click the “help” tab near the top right. If you are set to digest mode, note that it is in MIME format for the digests. There is an option for plain text if you don’t like the MIME format. The list is configured to send out a reminder once every two months.

    This isn’t as easily accessed as it was in the past, but it’s a heck of a lot better than no archiving at all.

    ~Jura


  • Dinosaur eggshells prove that dinosaurs weren’t molluscs.

    Chicken egg lit up using the candling method. Image from backyarchickens.com

    This week saw the release of a new paper that has implications for dinosaur metabolism.

    Dawson, R.R., Field, D.J., Hull, P.M., Zelenitsky, D.K., Therrien, F., Affek, H.P. 2020. Eggshell Geochemistry Reveals Ancestral Metabolic Thermoregulation in Dinosauria. Sci. Adv. 6:eaax9361. (Open Access)

    The paper makes some pretty hefty claims regarding dinosaur metabolism, and as such, has received a fair share of media coverage touting this as the latest evidence for “warm-blooded” (i.e., automatic endothermic) dinosaurs.

    Every time there is a major headline like that, I feel obliged to go back to the source to see what the media has likely overblown. In this case, media claims don’t seem that far off what was written in the actual paper, which is not necessarily good. Some of these claims do extend beyond the reach of the available evidence (e.g., there actually is no comparison with other contemporaneous reptiles of the region, weakening any arguments for metabolic thermoregulation).

    It’s been an age since I’ve done one of these paper breakdowns, but I think this one warrants a more thorough analysis, especially given the implications of the interpretations.

    Continue reading  Post ID 12222


  • The return of the scaly T. rex to modern paleo-art

    Tyrannosaurus rex walking towards camera. Art by John Sibbick.

    [NOTE: Post has been updated to include a section on scale size]

    This has certainly been an interesting year. Two papers dropped in the past three months that have put the brakes on a recent trend in paleo-art. That trend? Why the feather-coated T. rex of course.

    First, in March, we saw the release of a paper detailing a new species of Daspletosaurus and its relationship to D. torosus.

    Carr, T.D., Varricchio, D.J., Sedlmayr, J.C., Roberts, E.M., Moore, J.R. 2017. New Tyrannosaur with Evidence for Anagenesis and Crocodile-Like Facial Sensory System. Scientific Reports. 7(44942):1–11.

    In this paper, Carr et al. argue for the designation of a new Daspletosaurus species, D. horneri. The authors argue, based on skull shape and chronostratigraphic position, that D. horneri was the direct ancestor to D. torosus. I thought that the authors put forth a compelling argument for this anagenic event and backed up their position well. Interestingly, this part of the paper should have been the most controversial. As anyone who has read anything from Horner and Scanella over the past eight years can attest, arguing for a direct ancestor-descendant relationship for dinosaurs is difficult to do and even harder to win over others in the field. So it is somewhat surprising to see a case for anagenesis in Daspletosaurus taken so well by the palontological community. All the more so given that it involves a tyrannosaur, the poster children for “cool guy” dinosaurs.

    Instead, the most controversial part of the paper wound up being their soft-tissue reconstruction of the face for D. horneri. The author responsible for the soft-tissue reconstruction was Jayc Sedlmayr of Louisiana State University. Sedlmayr did his doctorate on osteological correlates for vasculature in extant archosaurs (birds & crocs). He is the seminal alumnus of the WitmerLab and thus is well within his wheelhouse for this type of soft-tissue reconstruction. Sedlmayr borrowed heavily from the work of another WitmerLab alumnus, Tobin Hieronymus, whose PhD work involved osteological correlates for integument on the skulls of animals. Although the skin is often well away from the underlying bones on most of the body, there are exceptions when it comes to the skull. There, areas that are not heavily muscled, tend to show intimate connections between the skin and the underlying bone. Hieronymus used these connections to determine how different integumentary appendages (scales, hair, feathers) affect the underlying bone (Hieronymus & Witmer 2007; Hieronymus et al. 2009). The authors found that the surface texture along the skull of D. horneri was “hummocky”. That is, it was covered in lots of closely packed ridges. According to Hieronymus & Witmer (2007), this texture correlates to scales as the overlying integumentary appendage. Thus, according to the authors, D. horneri had a scaly face (this is grossly oversimplified as the authors were able to piece together a variety of different integument variants along the skull, but you get the idea).

    Scaly tyrannosaur cannonball one had been shot.

    Then two weeks ago, we saw the release of another paper on tyrannosaur integument. However, unlike the previous paper, this one was specifically dedicated to integumentary types in tyrannosaurids.

    Bell, P.R., Campione, N.E., Persons, W.S., Currie, P.J., Larson, P.L., Tanke, D.H., Bakker, R.T. 2017. Tyrannosauroid Integument Reveals Conflicting Patterns of Gigantism and Feather Evolution. Biology Letters. 13:20170092

    In this paper, the authors set out to survey all known instances of “skin” impressions for tyrannosaurids. Their list of taxa included Albertosaurus, Tarbosaurus, Daspletosaurus, and Gorgosaurus. Their results pretty definitively indicated that scales were the predominant integumentary appendage on tyrannosaurids. The authors then went on to speculate why that would be if earlier tyrannosauroids had filamentous integument. They performed an ancestral character state reconstruction based on Parsimony and Bayesian-based trees from Brussatte and Carr 2016. Their results found that filaments came out strongly as the ancestral character for tyrannosauroids, but by no later than Tyrannosauridae proper, a reversion to scales had taken effect. The authors attributed this to body size evolution. Namely, larger tyrannosauroids reverted to scales over protofeathers.

    Cannonball number 2 had just been shot.

    Continue reading  Post ID 12222


  • New study shreds the dinosaur family tree (and exposes double-standards in Phylogenetic Nomenclature)

    Figurative illustration of the new phylogeny by Baron et al. 2017

    Most folks who visit my site by now have seen the big dinosaur news that has hit the interwebs. A new study from Matthew Baron, David Norman and Paul Barrett from University of Cambridge and the Natural History Museum of London, has seriously challenged the classic interpretation of dinosaur phylogeny.

    Baron, M.G., Norman, D.B., Barrett, P.M. 2017. A New Hypothesis of Dinosaur Relationships and Early Dinosaur Evolution. Nature. 543:501–512.

    Classical dinosaur phylogenetics

    Although originally thought of as two unrelated branches of Reptilia that grew to immense size during the Mesozoic (e.g., Charig et al. 1965), for the last 43 years the group, Dinosauria, has been considered monophyletic (i.e., sharing a single origin) with the subgroups, Saurischia & Ornithischia, forming the first major branches within the group (Bakker et al. 1974). Saurischians, or “reptile hips” were aligned together by their similar hip shapes, skull characters (e.g., open antorbital fenestrae), and inferred soft tissues (e.g., air sacs). Ornithischians, or “bird hips” shared a hip structure that was superficially similar to that of birds, with a pubis that pointed caudally rather than rostrally, along with a variety of unique skull characters such as a neomorphic bone known as the predentary.

    Study after study showed that this relationship was sound, and so it stayed that way. The problem with getting the same answer over and over again is that one eventually stops questioning it. Consistent results become  common knowledge, and may even graduate to dogma. That’s not so bad if that common knowledge is true, but all too often many of these “obvious” cases wind up being just so stories upon closer inspection.

    Continue reading  Post ID 12222


  • Modern-day paleo myths: Dinosaurs as lizards

    Paleomyths

    In this day and age there are no shortage of books, websites, and videos dedicated to debunking classic paleo myths. The majority of this mythbusting focuses on myths about dinosaurs. As the poster children for paleontology, this isn’t that surprising. With so many takes on this subject it comes as no surprise that all of the classic dinosaur myths have long since been debunked, such as dinosaurs as low-energy tail draggers, walking around like Godzilla, being evolutionary failures, inferiority to mammals, being pee brained monsters, etc.

    However, as quickly as these classic dinosaur myths have been eradicated, new ones have come and taken their place. These myths/misconceptions are routinely cited today without any question despite being just as erroneous as the myths that preceded them.

    This is the start of a new series I want to cover on the site: dispelling modern myths in vertebrate paleontology. Given the bent of my website, these myths/misconceptions will largely stay focused on reptile-related animals, though I am open to taking the occasional foray into other animal groups if the myths are egregious enough (which is to say that suggestions are welcomed).

    The seminal installment for this series is one that I see mentioned time and again:

    “Dinosaurs were once thought of as big lizards.”

    Continue reading  Post ID 12222


  • Jurassic World Review

    It's here!
    It’s here!

    I figured if I was going to do a Jurassic World-related post on Stegosaurus I might as well follow it up with a review for the film. I grossly underestimated the draw of dinosaurs to the cinema. Despite 22 years of Jurassic Park, Walking with Dinosaurs (BBC version, not the Disney thing), and so on, people never seem to be burnt out on dinosaurs. That’s good news for paleontology (yay!), and also for movies seeing as how Jurassic World just raked in a record-breaking $208.8 million domestic in its opening weekend.

    So what did I think?  In short: I liked it and found it to be a worthy successor to the franchise.

    If you’d like the longer, spoiler-ridden version click on the jump.
    Continue reading  Post ID 12222


  • Jurassic World and the case of the droopy-tailed Stegosaurus

    As I write this the US premiere of Jurassic World is just around the corner. I had gone back and forth regarding this post given that we currently know very little about the film and as such the interpretations written about here and elsewhere may well be pointless by the time the film premieres.

    Ultimately I decided to post this anyway since the overall thrust of the article should remain true regardless of how the film pans out.


    Now there has been a lot of buzz around Jurassic World since it was first announced last year. The buzz has been mixed, but fairly positive. I suspect this was, in part, because everyone was happy to hear that the godawful military dinosaur idea was shelved in favour of a more “traditional” JP franchise storyline. Nonetheless the movie has still drawn its fair share of detractors, including myself. Most of the people who are unhappy with the film are either paleontologists, or hardcore dinophiles. Many of the problems leveled at the film have to do with the portrayal of the extinct animals. The problems are actually myriad ranging from pterosaurs capable of picking up humans using grasping feet, mosasaurs that are twice the size of blue whales, sauropods covered in elephant skin rather than scales (a problem not unique to Jurassic World), everything about Velociraptor, and of course Indominus rex.  My biggest beef with the film is that the dinosaurs are not being shown as dinosaurs so much as monsters. However, after The Lost World: Jurassic Park came out it became pretty evident that Spielberg’s original vision of portraying dinosaurs as animals had been shelved in favour of the more entertainment-friendly movie monster approach. However, for what seems like a majority of the detractors, the biggest gripe with the film has to do with a lack of  feathers on pretty much all the dinosaurs. This seems to be a common theme these days with a particularly vocal group of dinophiles and paleontologists strongly pushing for the feathering of every dinosaur in sight and insisting that all media that portrays scaly (erroneously called: “naked”) dinosaurs is inaccurate. Never mind the fact that a feathered, pack-hunting, 2 meter tall Velociraptor mongoliensis is still every bit as inaccurate as a scaly one.

    Anyway, I digress. Dealing with the overwhelming amount of internet drama surrounding Jurassic World (and the media depiction of dinosaurs in general) is a topic for another day. My reason for writing this post is centered around one particular criticism that popped up a few weeks ago.

    Continue reading  Post ID 12222


  • Tall spines and sailed backs: A survey of sailbacks across time

    One of the quintessential depictions of prehistoric times is that of an ancient, often volcano ridden, landscape full of animals bearing large showy sails of skin stretched over their backs. Sailbacked animals are rather rare in our modern day and age, but back in the Mesozoic and Paleozoic there were sails a plenty.

    By far the most popular sailbacked taxa of all time would be the pelycosaurs in the genus Dimetrodon. These were some of the largest predators of the Permian (up to 4.6 meters [15 feet] long in the largest species). Dimetrodon lived alongside other sailbacked pelycosaurs including the genus Edaphosaurus. These were large herbivores (~3.5 m [11.5 ft] in length) that evolved their sails independently from Dimetrodon. The Permian saw many species of sphenacodontids and edaphosaurids, many of which sported these showy sails (Fig. 1. [1–8]).

    SailbackRoster
    Fig. 1. A brief survey of the sailbacks of prehistory. Permian sailbacks, the sphenacodontids: Dimetrodon(1), Sphenacodon(2), Secodontosaurus(3), and Ctenospondylus(4). The edaphosaurids: Edaphosaurus(5), Ianthasaurus (6), Echinerpeton(7), Lupeosaurus(8). The temnospondyl: Platyhystrix(9). Triassic sailbacks, the rauisuchians: Arizonasaurus(10), Ctenosauriscus(11), Lotosaurus(12), and Xilousuchus(13). Cretaceous sailbacks, the theropods: Spinosaurus(14), Suchomimus (15), Acrocanthosaurus (16), and Concavenator (17). The ornithopod: Ouranosaurus (18), and the sauropod: Amargasaurus (19). Image credits: Dmitry Bogdanov (1–2, 8, 14–15), Arthur Weaseley (5, 19), Smokeybjb (7), Nobu Tamura (3–4, 6, 8–9, 10–12), Sterling Nesbitt (13), Laurel D. Austin (16), Steven O’Connor (17), Sergio Pérez (18).

    However sails were hardly a pelycosaur novelty. The contemporaneous temnospondyl Platyhystrix rugosus (Fig. 1 [9]) also adorned a showy sail.

    Fast forward 47 million years into the Triassic and we find the rauisuchians Arizonasaurus babbitti, Lotosaurus adentus, Xilousuchus sapingensis, and Ctenosauriscus koeneniall bearing showing sails on their backs (Fig. 1 [10–13]). Much like in the Permian, many of these taxa were contemporaneous and, while related, many likely evolved their sails separately from one another.

    There are currently no fossils of sailbacked tetrapods in the Jurassic (as far as I know. Feel free to chime in in the comments if you know of some examples). However the Early Cretaceous gave  us a preponderance of sailbacked dinosaurs (Fig. 1 [14–19]) including the cinematically famous theropod Spinosaurus aegyptiacus, the contemporaneous hadrosaur Ouranosaurus nigeriensis, the gharial-mimic Suchomimus tenerensis, the potentially dual sailed sauropod Amargasaurus cazaui, as well as the allosauroids Acrocanthosaurus atokensis, and Concavenator corcovatus. Lastly, the discovery announced last year (and just now coming to light in the news) of better remains for the giant ornithomimid Deinocheirus mirificus have revealed that it too may have sported a small sail along its back.

    Once again we find a group of related, largely contemporaneous, animals, most of which probably evolved their sails separately.

    Such a huge collection of sailbacked animals all living around the same time (and sometimes the same place) has begged for some type of functional explanation. The usual go-to for large, showy surfaces like these or the plates of Stegosaurus has been thermoregulation. The thinking being that blood pumped through a large surface area like this, when exposed to the sun, has the ability to warm up faster than other areas of the body. Conversely when the sail is placed crosswise to a wind stream, or parallel to the orientation of the sun, heat will radiate out into the environment faster than other areas of the body. That most sailbacked dinosaurs were “localized” to equatorial areas, coupled with the large sizes of all the taxa (1-10 tonnes depending in species) has favoured a cooling mechanism function for dinosaur sails. Whereas a heating function has been presumed to be the primary function for sails in Dimetrodon and Edaphosaurus. No real function has been ascribed to the sails in rauisuchians or Platyhystrix, though this is probably due to a lack of knowledge/interest in these groups.

    Alternate functions proposed for these sails have included a self-righting mechanism for swimming, sexual signaling and other presumed display functions. In certain cases, namely Spinosaurus aegyptiacus and Ouranosaurus nigeriensis, it has even been argued that the enlarged spines did not support a sail, but rather were supports for a large, fatty hump akin to that of camels or bison (Bailey 1996, 1997).

    Given the wealth of hypotheses for potential sail functions it would be beneficial to first understand what extant sailbacked taxa use their sails for. Unfortunately—though unsurprisingly—there are few if any scientific studies on sail use in extant sailbacked animals. This has lead to the apparent assumption that there are no extant vertebrates with sailbacks.

    There are, in fact, quite a few sailbacked animals alive today. These include various fish, amphibians and even reptile species. Learning what these taxa use their sails for may offer us a glimpse at what extinct animals were doing with their sails.
    Continue reading  Post ID 12222


  • “Feathers” on the big, “feathers” on the small, but “feathers” for dinosaurs one and all?

     

    Yutyrannus artwork by Brian Choo. Sciurumimus artwork by Arkady Rose

    This year has seen the discovery of two big deal dinosaur specimens. At least they are a big deal in regards to dinosaur integument and, possibly, metabolism.

    First off from a few months ago we had the announcement the theropod Yutyrannus hauli, the “beautiful feathered tyrant.”

    Xu, X., Kebai, W., Ke, Z., Qingyu, M., Lida, X., Sullivan, C., Dongyu, H., Shuqing, C., Shuo, W. 2012. A Gigantic Feathered Dinosaur from the Lower Cretaceous of China. Nature. Vol.484:92-95

    This was not just a single fossil, but a collection of three fossils (one might be tempted to call it a family group, but that would only be speculation). As with all other dinosaur fossils that have been found to have filamentous integument, these guys come from Liaoning, China. They are suspected to have come from the Jehol Group in the Yixian formation. I say suspected because the complete three specimen set was a purchase from a fossil dealer, an all too common occurrence for Chinese fossils. As such the provenance information is unknown. A lot of Chinese fossil dealers don’t like to give away the location of their find due to the potential loss of other profitable specimens. This current trend in China is a good example of what happens when capitalism comes into play with fossil collecting (something that the U.S. has been mostly, but not entirely, able to avoid). So it is currently uncertain whether these fossils are from the Yixian. However given that all the others guys are too it is probably a good bet. Given the sketchy nature in which many Yixian fossils are collected, coupled with the possibly large consequences of the find, one should naturally be skeptical of the fossil. Had it been one individual on multiple slabs I would question its validity as a real thing. However since Y.huali is known from three individuals, and the filaments seem to follow a consistent pattern around the body (compare that to the helter-skelter nature of Tianyulong‘s preservation), forgery seems unlikely. These guys are probably the real deal. This has some potentially far reaching consequences to interpretations of Late Cretaceous coelurosaurs and the Jehol Biota itself (more on this in a bit).

    The second announcement came just a few weeks ago. This was the discovery of a potentially new, miniscule theropod from Bavaria Germany.

    Rauhut, O.W.M., Foth, C., Tischlinger, H., Norell, M.A. 2012. Exceptionally Preserved Juvenile Megalosauroid Theropod Dinosaur with Filamentous Integument from the Late Jurassic of Germany. PNAS Early Edition:1203238109v1-201203238.

    The specimen is exceptionally well preserved. So well preserved in fact that it actually looks like a plastic toy. While this degree of preservation warrants importance all its own, the main interest behind this new guy—dubbed: Sciurumimus albersdoerferi (Albersdörfer’s squirrel mimic)—is the apparent presence of filamentous integument on the body coupled with its apparent placement among much more basal theropods. This discovery has far reaching consequences for theropod integument interpretations. Note: As with Y.hauli, Sciurumimus albersdoerferi was also purchased from a private collector. I don’t suspect forgery here either as this was in Germany, where fossil dealing is neither a big problem nor a lucrative business. The exceptional detail on the specimen would also require a substantial amount of theropod knowledge to pull off. Anyone having that amount of knowledge is more likely to be a real paleontologist than a get rich quick forger.

    Continue reading  Post ID 12222