The Validity of Supersaurus vivianae

Supersaurus vivianae is a Diplodocid Sauropod (one of many from the Morrison formation). The holotype (BYU 9025) is a scapulocoracoid 2.2m long. Jensen described this as a Brachiosaurid, along with UltrasaurusDystylosaurus (Jensen, 1985). Later, Jensen realized Supersaurus was a Diplodocid, and he transferred the dorsal from Ultrasaurus (which was the holotype of Ultrasaurus) to Supersaurus (as he realized it was a posterior Diplodocid dorsal, not an anterior Brachiosaurid dorsal) & made the holotype of Ultrasaurus the giant 2.5m scapulocoracoid. (Jensen, 1987). Curtice, Stadtman, & Curtice (1996), knowing that the ICZN does not allow the holotype to be transferred, & thus Ultrasaurus (which by this point had been renamed Ultrasauros, because a small, non-diagnostic, fragmentary, piece of crap Sauropod from South Korea had been named Ultrasaurus in 1983) became a junior synonym of Supersaurus, with the giant scapulocoracoid referred to Brachiosaurus. Curtice & Stadtman (2001) referred Dystylosaurus to Supersaurus. Thus the Jensen Three became the Jensen One.

 

In 2007, a new specimen, WDC-DMJ-021, nicknamed Jimbo, was described. Jimbo is a rather complete Diplodocid skeleton. Lovelace, Hartman, & Wahl (2007) referred it to Supersaurus. However, Jimbo does not preserve a scapula or a coracoid. So what was their reasoning for this referral? They referred Jimbo to Supersaurus based on the similarities to the other postcranial elements (cervicals, dorsals, caudals, etc) from the Dry Mesa Quarry.

 

supersaurus-jimbo-skeletal-sh

Fig. 1. Skeletal restoration of Jimbo, compared to Barosaurus lentusBrontosaurus louisae. Skeletals by Scott Hartman. Used for educational purposes only.


In 2016, an SVPCA abstract was released by Mike Taylor & Matt Wedel of SVPOW! In this abstract,  they refer (rather convincingly) a pair of three cervicals (from BYU quarry  3GR) belonging to a 33-37m Barosaurus. They also refer BYU 9024 (from Dry Mesa quarry), the longest cervical known at 137cm, to Barosaurus, after originally being referred to Supersaurus by both Jensen (1987) & Lovelace, et al (2007). This belongs to a Titanic 45+m Barosaurus specimen. As well, Taylor & Wedel (in press) state that because of lack of cervical bifurcation & a pronounced ventral keel, Dystylosaurus can’t be referred to Supersaurus, or any other Diplodocid for that matter. Thus Dystylosaurus is most likely a valid genus once more. As well, the Ultrasauros scapulocoracoid, referred to Brachiosaurus (Curtice, et al 1996; Taylor, 2009), most likely doesn’t belong to Brachiosaurus, & is likely a valid genus (Paul, 2012). So the Jensen One had once more become the Jensen Three.

This creates a multitude of problems. Jimbo was referred to Supersaurus based on comparisons with the other Diplodocid postcranial material at Dry Mesa. This won’t work if the postcranial is more than Supersaurus. We know for sure there’s a Barosaurus & a Dystylosaurus present at the site, & we can’t just automatically assume all of the other Dry Mesa material is Supersaurus. So let’s take a look at Supersaurus vivianae in detail. The first step is to look at the holotype specimen, BYU 9025. Tschopp, Mateus, & Benson (2015) listed six characters that distinguish BYU 9025 from Diplodocus:

362. Angle between the acromial ridge and scapular blade – This differs between the right and left scapulocoracoids from the type locality, and the range overlaps with the range in other diplodocid species, although it’s closer to the apatosaurine average than the diplodocine average.
366. Orientation of glenoid – This is variable (perhaps ontogenetically) in apatosaurines, and individually varies in Diplodocus carnegii. Supersaurus has the typical non-apatosaurine state.
367. Shape of acromial edge of blade – Individually variable in DiplodocusSeismosaurus and lacks a clear phylogenetic signal elsewhere.
369. Ovate muscle scar on lateral face of blade at base – Variable in Brontosaurus parvus and Seismosaurus hallorum.
370. Subtriangular projection at base of blade, posterior to the glenoid – Individually variable in B. parvus and S. hallorum.
371. Distal expansion of blade – Individually variable in B. parvus, with BYU 1252-18531 being the only diplodocid to resemble Supersaurus in this regard.

So the takeaway here is that both Brontosaurus parvus UW 15556 & BYU 1252-18531 differ in a few scapular characters, & that Diplodocid scapulae may not be particularly reliable for diagnosing a species or genus. Jimbo is definitely a distinct taxon, but given that we can’t say for sure what Dry Mesa material is & is not Supersaurus, I recommend for the moment to retain Jimbo as “Supersaurus” sp., & to wait until we discover a new specimen which has overlap with both Jimbo & BYU 9025. At the moment, I still leave both as Supersaurinins (along with Dinheirosaurus, Australodocus, Tornieria). Another thing to realize is we continue to underestimate Morrison Sauropod diversity (which will definitely be a post at another time). Tally ho folks, & we will have more Sauropod stuff soon!

References


  1. Curtice, B.; Stadtman, K. (2001). “The demise of Dystylosaurus edwini and a revision of Supersaurus vivianae“. In McCord, R.D.; Boaz, D. Western Association of Vertebrate Paleontologists and Southwest Paleontological Symposium – Proceedings 2001. Mesa Southwest Museum Bulletin 8. pp. 33–40.
  2. Curtice, B., Stadtman, K., and Curtice, L. (1996) “A reassessment of Ultrasauros macintoshi (Jensen, 1985).” Pp. 87-95 in M. Morales (ed.), The Continental Jurassic: Transactions of the Continental Jurassic Symposium, Museum of Northern Arizona Bulletin number 60.
  3. Jensen, J.A. (1985). “Three new sauropod dinosaurs from the Upper Jurassic of Colorado.” Great Basin Naturalist, 45: 697-709.
  4. Jensen, J.A. (1987). “New brachiosaur material from the Late Jurassic of Utah and Colorado”. The Great Basin Naturalist 47 (4): 592–608.
  5. Lovelace, D. M.; Hartman, S. A.; Wahl, W. R. (2007). “Morphology of a specimen of Supersaurus (Dinosauria, Sauropoda) from the Morrison Formation of Wyoming, and a re-evaluation of diplodocid phylogeny”. Arquivos do Museu Nacional 65 (4): 527–544.
  6. Paul, Gregory S. (2012). “Some Notes on the Diverse Brachiosaurid Sauropods of the Late Jurassic of North America, Europe and Africa”
  7. Taylor, M.P. (2009). “A Re-evaluation of Brachiosaurus altithorax Riggs 1903 (Dinosauria, Sauropod) and its generic separation from Giraffatitan brancai (Janensch 1914).”Journal of Vertebrate Paleontology, 29(3): 787-806.
  8. Taylor, M.P., & Wedel, M. J. (In press). “How big did Barosaurus get?” SVPCA Liverpool 2016 Abstracts: 30.
  9. Tschopp, E., Mateus O., & Benson R. B. J. (2015). “A specimen-level phylogenetic analysis and taxonomic revision of Diplodocidae (Dinosauria, Sauropoda).” PeerJ. 3, e857.

SuperBarosaurus and Dystylosaurus

I have discovered some very interesting news in the Diplodocid camp lately. An SVPCA abstract by Mike Taylor and Matt Wedel (here, on pg. 30) described some BYU cervicals which belong to Barosaurus. We all know and love Barosaurus of course. From the mighty AMNH 6341, the quintessential Barosaurus specimen:

Fig. 1. AMNH 6341. Image copyright the AMNH.


to ROM 3670, the largest known Barosaurus specimen, at roughly 27m long.

Fig. 2. ROM 3670, skeletal restoration by Scott Hartman.


In this abstract, they describe a set of three dorsal vertebrae from BYU quarry 3GR (which is what I will refer to the specimens as from now on). These vertebrae are of uncertain position exactly, but based on neural spine bifurcation the last one (vertebra C) belongs to C9-C11. The C9-C11 of AMNH 6341 are 685, 737, and 775mm long, respectively.

Image result for amnh 6341

Fig. 3. Left column, C9-12. right column, C14-16. From Taylor & Wedel, 2013b.


Vertebra C from BYU 3GR is 1220mm. This vertebrae is 1.57 to 1.78 times longer than that of AMNH 6341, and belongs to a neck 13.3-15.1m long, as the AMNH Barosaurus has an 8.5m neck. This implies a Barosaurus 33 to 37.38m long. That’s a huge size leap for Barosaurus.

Incredibly though, the story doesn’t end there. BYU 9024 is a very large cervical (in fact it’s the longest Sauropod cervical known, at 1330mm). This cervical was originally referred to Supersaurus, but it shares the same characters with Barosaurus as those of BYU 3GR (elongation, broad prezygapophyseal facets, “hinged” prezygapophyseal rami with dorsomedial and dorsolateral faces, narrow, posteriorly set diapophyses bearing posterior tubercles, and wing-like postzygadiapophyseal laminae). This vertebra (also potentially C9) is twice as long as the C9 of AMNH 6341. Thus this implies a neck twice as long as AMNH 6341, at 17m. Let me reiterate that: 17 METERS! So a nice quick scale up of AMNH 6341 to a 17m long neck yields a total length of 42m for BYU 9024! Just some perspective on this, the total length of Puertasaurus (widely considered to be one of the largest Dinosaurs) is 32m (per my skeletal, see below).

Puertasaurus reuili Paper Me

Fig. 4. Skeletal restoration of Puertasaurus reuili. Scale bar equals 4m.


And here is one of Scott Hartman’s lovely Barosaurus skeletals scaled to a 17m neck.

Super Barosaurus

Fig. 5. Barosaurus with a 17m neck. Chart created by RandomDinos.


Super Barosaurus is awesome, but this isn’t the only news from this abstract. In the abstract, they also state:

Dystylosaurus has also been referred to Supersaurus. Although the holotype and only vertebra is clearly a diplodocid anterior dorsal (it has dual centroprezygapophyseal laminae, a large cotyle and “drooping” parapophyses), its tall, unsplit neural spine and pronounced ventral keel prevent assignment to any known diplodocid. It may be a valid, distinct genus.”

Now, as we all know, Dystylosaurus is a part of the mess that is the Dry Mesa Sauropods. The three, Supersaurus, Ultrasauros, and Dystylosaurus were all described as separate genera, until Curtice, Stadtman, & Curtice (1996) and Curtice & Stadtman (2001) reanalyzed the remains and found that Dystylosaurus was likely Supersaurus, and the holotype dorsal of Ultrasauros actually belongs to Supersaurus, and the giant Ultrasauros scapulocoracoid is Brachiosaurus (which I don’t agree with, but that’s for another time). However, a Taylor & Wedel show, Dystyosaurus can’t be presently referred to any existing Diplodocid species, and may once more be distinct. Wooo! #Dystylosaurushype!

What do you guys think? Let me know below.

References


  1. Taylor, M.P., & Wedel, M. J. (In press). “How big did Barosaurus get?” SVPCA Liverpool 2016 Abstracts: 30.
  2. Curtice, B., Stadtman, K., and Curtice, L. (1996) “A re-assessment of Ultrasauros macintoshi (Jensen, 1985).” Pp. 87-95 in M. Morales (ed.), The Continental Jurassic: Transactions of the Continental Jurassic Symposium, Museum of Northern Arizona Bulletin number 60.
  3. Curtice, B.; Stadtman, K. (2001). “The demise of Dystylosaurus edwini and a revision of Supersaurus vivianae“. In McCord, R.D.; Boaz, D. Western Association of Vertebrate Paleontologists and Southwest Paleontological Symposium – Proceedings 2001. Mesa Southwest Museum Bulletin. 8. pp. 33–40.

 

Thoughts on Aegyptosaurus

Ah Aegyptosaurus. We all know that Ernst Stromer described this for a set of appendicular and axial elements from the Cenomanian epoch of Egypt’s Baharya Oasis. And of course, along with Spinosaurus and Carcharodontosaurus, the remains were obliterated by RAF bombing on April 24/25 1944 (damn Brits…), and the only known specimen of Aegyptosaurus was forever condemned to the history books.

Aegyptosaurus-019

Fossil material of Aegyptosaurus (Stromer, 1932a).


 

Or so it would seem. Fortunately, through communication with several members of the Paleo community, I managed to get my hands on the original description paper. So (naturally) I’ve spent a lot of time looking at the fossil material as figured by Stromer.

So what can we see? Well the middle caudals are procoelous, which means that this is at least beyond Malawisaurus in derivedness (one day will be a post on the different types of articulations in vertebrae). Interestingly, the femur of Aegyptosaurus is very similar to the femora of both Lognkosauria and Euhelopodidae (two unrelated groups who developed VERY similar femoral morphs so much so that sometimes it’s hard to tell which belongs to which (cough Ruyangosaurus cough). Which means that either the femur and caudals are from different genera, or (more likely) that Aegyptosaurus is a Lognkosaurian of sorts. Don’t believe me, check it out below.

Titanosaur Femora

Comparison of various Somphospondyl femora, modified by Paleo King. Note how similar the femora of Ruyangosaurus, Malawisaurus, and Daxiatitan are to Aegyptosaurus. Same massive lateral tuberosity and all.


 

Personally I fully expect this to be a Lognkosaur. Same femur morphology and procoelous middle caudals (as in Mendozasaurus, Futalognkosaurus, and Dreadnoughtus). However, due to the humerus morphology (the proximal humeral head is nowhere near as ridiculously expanded transversely as in Notocolossus, and is still even less so than that of Dreadnoughtus) Aegyptosaurus may be a much more basal Lognkosaur, perhaps intermediate between Malawisaurus and Mendozasaurus.

Notocolossus-003

Notocolossus humerus, along with the pubis and pes. Note how massive the humeral head is compared to Aegyptosaurus.


 

Of particular interest to note is that Aegyptosaurus actually has been included in a phylogenetic analysis before. This is Curry-Rogers (2005). When it was released it was the definitive analysis on Titanosaurs. And even now, 11 years later, it still holds up quite well, despite many former characters no longer being accurate enough, and some of the character codings are wrong (seriously, Argentinosaurus as an Opisthocoelicaudiine?! That makes about as much sense as Huabeisaurus as a Nemegtosaurid). In the only MPT Aegyptosaurus was included in, it was found within a large polytomy of essentially every non-Saltasauroid Titanosaur with the exception of Malawisaurus, Paralititan, and the (definitely not a Titanosaur) Phuwiangosaurus, though this polytomy also includes the oddly out of place Alamosaurus, Aeolosaurus, and Agustinia (which may not even be a Titanosaur!).

One more thing: Lapparent (1960) referred a caudal sequence to Aegyptosaurus, based on “a short, compact vertebral centrum that is flattened laterally and not dorsoventrally; they are strongly procoelous. These characters indicate the family Titanosauridae…leads me to refer these elements to Aegyptosaurus baharijensis.” Now I don’t have the figures in my copy of Lapparent, 1960 (hint hint), but these caudals MAY be referrable to Aegyptosaurus. However in recent years another new Titanosaur emerged, Paralititan stromeri (Smith, et al 2001), and this genus also features procoelous caudals (no middle caudals are known, but the anterior caudals are). As well, the Continental Intercalaire formation from which these caudals were described is from the Albian epoch from Algeria, while both Aegyptosaurus and Paralititan are from the Cenomanian in Egypt. Do I think these caudals belong to Aegyptosaurus or Paralititan? No, but they may be from a close relative of either Lognkosauria or Argyrosauridae (maybe even Euhelopodids, which are also known for procoelous caudals).

So to conclude, Aegyptosaurus  was a potential Lognkosaur which was likely a valid genus, and coexisted alongside the much larger Paralititan. Feel free to leave any comments below if I missed something (or if someone has a copy of Lapparent 1960 with figures).

References


Panamericansaurus, translated!

Yep. In following the footsteps of the Polyglot Paleo site, I’ve begun translating the papers that have so far been untranslated. The first one is Panamericansaurus. Why Panamericansaurus you might ask? Welp, I’m just working through the entirety of Titanosauria at the moment, so I’m just going from advanced to basal.

I’m assuming you are interested in this paper, fair enough, here you go:

In PDF form: file: https://drive.google.com/file/d/0B8Yj0tBZ6RyTV2NhQzJQQlVPaDQ/view

In Google Docs form: https://docs.google.com/document/d/1gbq8tHBVii53rWMDNNjx0MeE6_ucgrxY-iLPI0LvvmM/edit

Original Citation: Calvo, J.O. & Porfiri, J.D. (2010). “Panamericansaurus schroederi gen. nov. sp. nov. Un nuevo Sauropoda (Titanosauridae-Aeolosaurini) de la Provincia del Neuquén, Cretácico Superior de Patagonia, Argentina”. Brazilian Geographical Journal: Geosciences and Humanities research medium 1: 100–115.

Brachiosaurs redux! I – Sonorasaurus

Rejoice! Yesterday marked the release of the redescription of Sonorasaurus thompsoni, the oldest (confirmed) Brachiosaurid known, and the only one known from my current state of residence. This paper can be read here (I already downloaded the paper from Sci-Hub, so you can just download and read).

And as a nice pleasant surprise, Brachiosauridae continues to be recovered as monophyletic, Europasaurus is the most basal, Sonorasaurus & Giraffatitan come out as sister taxon, and VenenosaurusLusotitan show up within Brachiosauridae.

Sonorasaurus-Reassessment-026

The strict consensus tree, based on the data matrix of D’Emic (2012), with a couple additional characters, as well as (obviously) the addition of Sonorasaurus.  _________________________________________________________________

On the bright side, now I have an even better reason to get around to restoring Sonorasaurus, with pretty much every single known bone photographed now, this’ll be a whole lot easier.

This paper was published by D’Emic, Foreman, & Jud, and as (unfortunately) seems to continue with D’Emic’s papers, they continue to be published under a paywall. Just think about it: a juvenile Barosaurus specimen (published in JVP); the description of a (likely) Camarasaurid from the USA (the oldest one known from the Cretaceous) also was published in JVP; a paper on a baby Rapetosaurus specimen (he isn’t the head author, but he’s still on it) was published in Science Mag. The (controversial) paper on Astrophocaudia, a new specimen of Cedarosaurus, and the (not very convincing in my eyes) referral of Paluxysaurus jonesi to Sauroposeidon proteles (that’s a lot for one paper, eh?) was published in the Journal of Systematic Paleontology (also owned by Taylor & Francis). I’m really starting to wonder if some paleontologists have even been paying attention to what SV-POW! and others in the blogosphere have been saying (Open-access, please!).

References                                                                                                                                                          ………………………………………………………………………………………………………………….

D’Emic, M.D., Foreman, B.Z., Jud, N.A. (2016), Anatomy, systematics, paleoenvironment, and age of the sauropod dinosaur Sonorasaurus thompsoni from the Cretaceous of Arizona, USA. Journal of Paleontology.

Ratkevich, R (1998). “New Cretaceous brachiosaurid dinosaur, Sonorasaurus thompsoni gen et sp. nov, from Arizona.” Arizona-Nevada Academy of Science 31; 71-82.

In the beginning…

This is the post excerpt.

…there was one blog post.

Hi, I’m Gunnar Bivens. I’m an amateur Paleontologist. I study in my free time (what with school and all). I have had an interest in Dinosaurs my whole life. As such, they will be the main focus of this blog. However, I also have profound interest in Rock N Roll (more of what we consider classic rock [AC/DC, Guns N Roses, Mötley Crüe, Metallica, Van Halen, Dio, Bon Jovi, Queen, Black Sabbath], but I do also like new bands too [Avenged Sevenfold, Nickelback). I also find extreme interest in the military, specifically the weaponry (tanks, firearms, warships). As with most other people, I do love my video games (Call of Duty, World of Tanks/World of Warships, Minecraft).

I will try to post as often as possible.