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TWO new ceratopsids
Topic Started: May 18 2016, 03:05 PM (896 Views)
TheNotFakeDK
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Hold on to your butts everyone, because we've got not one but two new species of ceratopsid published in the same day, both in open access to boot.

From the Wahweap formation of Diabloceratops fame, we've got Machairoceratops cronusi, which sports an impressive pair of forward curving epoccipitals.

Posted Image

Article: http://westerndigs.org/new-sword-horned-dinosaur-unearthed-in-utah/
Paper: http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0154403


And after much deliberation, the Judith skull has finally been described and published. Alas, she hasn't revived Ceratops as some had suspected, but her new genus name, Spiclypeus, is a breath of fresh air amongst all the "something-ceratops" we've got kicking about. Reminds me of the likes of Agathaumas or Laelaps.

Paper: http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0154218
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Incinerox
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Āeksiot Zaldrīzoti

Okay, now Machairoceratops is a weird one.
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Acinonyx Jubatus
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I AM THE UNSHRINKWRAPPER!

I agree. Spiclypeus has the better name, though.
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BossMan, Jake
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Son of God

They only have the frill and brow horn yet they are able to determine if it had any nasal horns or not?
Edited by BossMan, Jake, May 18 2016, 11:25 PM.
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TheNotFakeDK
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Given that it's most closely related to Diabloceratops, Nasutoceratops, Avaceratops and Albertaceratops, which all lack the traditional nasal horn, it can be assumed that Machairoceratops probably lacked a nasal horn as well.
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Ulquiorra
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The brow horns, combined with those large epoccipitals, makes Machairoceratops almost look like it has antlers, when you look at the skull from the side.
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Mathius Tyra
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Rat snake is love... Rat snake is life

Err... Anyone else thinking that Machairoceratops could easily be just a new specie of Diabloceratops?
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Posted Image Xenephos
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ᴀ ʟɪᴛᴛʟᴇ ᴏʙsᴇssᴇᴅ

I love how the horns are labeled.
"'Oh,' that's a horn."
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Jon Sam
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Hmm.. Spiclypeus is really interesting.
Machairoceratops too, But i think from the shape of the skull I guess it may be an Old Diabloceratops (Maybe an Alpha Male). Both species looks much
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Posted Image Flish
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I would not be surprised if this just turns out to be new Diabloceratops material.
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TheNotFakeDK
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To quote the relevant portions of the paper:

Quote:
 
Machairoceratops differs from the stratigraphically lower Diabloceratops in a number of key features including: a fan-shaped, subrectangular (rather than rectangular) stepped squamosal, an inferred (based on size and shape of the epijugal contact facet) smaller, elliptical (rather than tetrahedral) epijugal, two anterodorsally (rather than laterally) curved (p1) epiparietals on either side of a midline embayment, and a posteromedially oriented sulcus running the entire length of the posterior surface of the epiparietal loci (p1) ornamentation...

...Machairoceratops shares morphological features of the squamosal with yet another unnamed and stratigraphically lower taxon from the Wahweap Formation (Nipple Butte skull [UMNH VP 16704]). Specifically, the squamosals of each taxon are comparable in overall shape, being subrectangular rather than rectangular, suggesting that there may be at least two distinct lineages of centrosaurines through the Wahweap Formation (i.e., a Diabloceratops lineage and a Machairoceratops lineage). Additionally, the variation observed among the squamosals of these three taxa (i.e., Diabloceratops, Machairoceratops, and UMNH VP 16704) falls well outside the expected intraspecific variation for Diabloceratops based on variation known for other ceratopsids. Moreover, the temporal separation among the aforementioned taxa is similarly outside the expected temporal duration given known species turnover rates for other ceratopsians. Taken together, these attributes suggest the presence of a divergent centrosaurine ceratopsid from the upper member of the Wahweap Formation, thereby increasing the known centrosaurine diversity from the southern portion of Laramidia during the late Campanian.


So at the very least they've provided justification for naming it a distinct genus, which may or may not satisfy you depending where you sit on the lumper-splitter spectrum.
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