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RE: Small theropod dinosaurs from Morrison Formation of Como Bluff, Wyoming (free pdf)
Looks like my message fell victim to the DML chopping bug. Here's the complete
version that will hopefully post correctly-
This paper and Dalman's other one in this volume naming a new Allosaurus
species are... what's the word? Terrible. Admittedly, I've just skimmed them
so far, but let's look at his new supposed ceratosaurid Fosterovenator. The
holotype is a partial tibia with fused astragalus, and the paratype is a
supposed fibula "of a much larger individual". So how can it be referred to
Fosterovenator if it can't be compared to it? Maybe they both have
ceratosaurid features, you say? Dalman says the tibia "clearly belongs to a
basal tetanuran theropod that differs from all other known taxa from
the Morrison Formation by a strongly inclined anterior articular surface and by
the “C”-shaped incisura tibialis." Wait, what? An impossible ceratosaurid
tetanurine? Later we read "Fosterovenator churei (YPM VP 058267) is identified
as a ceratosaurid theropod, which based on its overall morphology is more
closely related to Elaphrosaurus than to Ceratosaurus." So... Elaphrosaurus is
a ceratosaurid too in Dalman's view? And just after that- "Therefore, based on
this evidence both the Fosterovenator and the Garden Park “Elaphrosaurus”
(Chure, 2001) most likely represent the first occurrence of basal Late Jurassic
abelisauroids in the Northern Hemisphere." Ohhh, so it's a tetanurine,
abelisauroid ceratosaurid? Triply impossible. Note nowhere in the paper is
the attempt even made to identify features that are most similar to
Ceratosaurus or Elaphrosaurus. Ironically, the tibia IS clearly tetanurine
because its fibular crest is widely separated from the lateral condyle, n
ot that Dalman mentions this character at all. So this is no ceratosaur. The
'fibula' on the other hand, is pretty certainly not a theropod fibula. There's
almost no distal taper to the shaft, the distal end is 84% as wide
anteroposteriorly as the proximal end, etc.. The distal end has the triangular
outline of a tetanurine tibia, so
uess is it's a tibia with a crushed and/or broken proximal end. And it's not
just the science that's bad, the editing gives it a run for its money. Behold
this wonderous section of text-
"In medial view the YPM VP 058267D tibia closely resembles the tibia of YPM VP
058267A, which is a small bone and most likely belongs to a juvenile
individual. Therefore, some of the morphological features may represent
ontogenetic variation. In medial view, the (YPM VP 058267A) tibia closely
resembles the tibia of some basal tetanuran theropods such as Neovenator and
Sinraptor, but also those of small abelisauroid theropods. YPM VP058267A is a
small bone and most likely belongs to a juvenile individual. Therefore, some of
the morphological features may represent ontogenetic variation."
Who edited this? Also note D is supposed to be the fibula, though the tibial
pieces are also labeled D in the figure, although the text clearly says the
proximal tibia is A. The distal tibia with attached astragalus is
alternatively identified as B or C, so who knows which is right for that one.
As for Allosaurus lucasi, note this is the specimen from Dalman et al.'s (2012)
SVP abstract. It's based on fragments that are photographed in Malkani-style-
low resolution with no indication of what are broken surfaces. In 2012, it was
reported to have four premaxillary teeth, but is here correctly described as
having five. Though claimed in both places to have an unusually short
premaxilla, it matches the A. fragilis premaxilla drawn next to it almost
exactly in length vs. height. The masterful editing is obvious two ways in
this figure alone- A. fragilis' picture is credited to Madsen 1993 instead of
1976, a mistake that is repeated everywhere including the bibliography; and
what's supposed to be Neovenator's premaxilla clearly is not, with a short body
and three teeth. As with Fosterovenator, Dalman refers another specimen to A.
lucasi, a smaller dentary fragment and supposed splenial fragment, that aren't
said to share any unique charac
bstract says "All the cranial elements, including the braincase, left
premaxilla, maxilla, quadratojugal, and dentary were CT scanned so that digital
3D reconstructions could be done, allowing morphological description and
comparisons", but there's no evidence of that here. In short, A. lucasi is
just a fragmentary A. fragilis.
Seriously, whoever edited these (the acknowledgements suggest Spencer Lucas)
was asleep at the wheel or just didn't care. I'd be very interested to know
how the claimed peer review by Lucas, Hunt, Foster and (the one who wisely
chose to remain) Anonymous went down.
References- Dalman, Paulina-Carabajal and Currie, 2012. A new large-bodied
theropod dinosaur from the Upper Morrison Formation (Late Jurassic, Tithonian)
of Colorado. Journal of Vertebrate Paleontology. Program and Abstracts 2012, 84.
Dalman, 2014a. Osteology of a large allosauroid theropod from the Upper
Jurassic (Tithonian) Morrison Formation of Colorado, USA. Volumina Jurassica.
12(2), 159-179.
Dalman, 2014b. New data on small theropod dinosaurs from the Upper Jurassic
Morrison Formation of Como Bluff, Wyoming, USA. Volumina Jurassica. 12(2),
181-196.
Mickey Mortimer
----------------------------------------
> Date: Mon, 15 Dec 2014 16:24:40 -0800
> From: mickey_mortimer111@msn.com
> To: dinosaur@usc.edu
> Subject: RE: Small theropod dinosaurs from Morrison Formation of Como Bluff,
> Wyoming (free pdf)
>
> This paper and Dalman's other one in this volume naming a new Allosaurus
> species are... what's the word? Terrible. Admittedly, I've just skimmed
> them so far, but let's look at his new supposed ceratosaurid Fosterovenator.
> The holotype is a partial tibia with fused astragalus, and the paratype is a
> supposed fibula "of a much larger individual". So how can it be referred to
> Fosterovenator if it can't be compared to it? Maybe they both have
> ceratosaurid features, you say? Dalman says the tibia "clearly belongs to a
> basal tetanuran theropod that differs from all other known taxa from
> the Morrison Formation by
and by the “C”-shaped incisura tibialis." Wait, what? An impossible
ceratosaurid tetanurine? Later we read "Fosterovenator churei (YPM VP 058267)
is identified as a ceratosaurid theropod, which based on its overall morphology
is more closely related to Elaphrosaurus than to Ceratosaurus." So...
Elaphrosaurus is a ceratosaurid too in Dalman's view? And just after that-
"Therefore, based on this evidence both the Fosterovenator and the Garden Park
“Elaphrosaurus” (Chure, 2001) most likely represent the first occurrence of
basal Late Jurassic abelisauroids in the Northern Hemisphere." Ohhh, so it's a
tetanurine, abelisauroid ceratosaurid? Triply impossible. Note nowhere in the
paper is the attempt even made to identify features that are most similar to
Ceratosaurus or Elaphrosaurus. Ironically, the tibia IS clearly tetanurine
because its fibular crest is widely separated from the lateral condyle, n
> ot that Dalman mentions this character at all. So this is no ceratosaur.
> The 'fibula' on the other hand, is pretty certainly not a theropod fibula.
> There's almost no distal taper to the shaft, the distal end is 84% as wide
> anteroposteriorly as the proximal end, etc.. The distal end has the
> triangular outline of a tetanurine tibia, so if this belongs to a theropod,
> my guess is it's a tibia with a crushed and/or broken proximal end. And it's
> not just the sci
> y. Behold this wonderous section of text-
>
> "In medial view the YPM VP 058267D tibia closely resembles the tibia of YPM
> VP 058267A, which is a small bone and most likely belongs to a juvenile
> individual. Therefore, some of the morphological features may represent
> ontogenetic variation. In medial view, the (YPM VP 058267A) tibia closely
> resembles the tibia of some basal tetanuran theropods such as Neovenator and
> Sinraptor, but also those of small abelisauroid theropods. YPM VP058267A is a
> small bone and most likely belongs to a juvenile individual. Therefore, some
> of the morphological features may represent ontogenetic variation."
>
> Who edited this
tibial pieces are also labeled D in the figure, although the text clearly says
the proximal tibia is A. The distal tibia with attached astragalus is
alternatively identified as B or C, so who knows which is right for that one.
>
> As for Allosaurus lucasi, note this is the specimen from Dalman et al.'s
> (2012) SVP abstract. It's based on fragments that are photographed in
> Malkani-style- low resolution with no indication of what are broken surfaces.
> In 2012, it was reported to have four premaxillary teeth, but is here
> correctly described as having five. Though claimed in both places to have an
> unusually short premaxilla, it matches the A. fragilis premaxilla drawn next
> to it almost exactly in length vs. height. The masterful editing is obvious
> two ways in this figure alone- A. fragilis' picture is credited to Madsen
> 1993 instead of 1976, a mistake that is repeated everywhere including the
> bibliography; and what's supposed to be Neovenator's premaxilla clearly is
> not, with a short body and three teeth. As with Fosterovenator, Dalman
> refers another specimen to A. lucasi, a smaller dentary fragment and supposed
> splenial fragment, that aren't said to share any unique characters with the
> dentary fragme
nt
> of the holotype. The SVP abstract says "All the cranial elements, including
> the braincase, left premaxilla, maxilla,
> t digital 3D reconstructions could be done, allowing morphological
> description and comparisons", but there's no evidence of that here. In
> short, A. lucasi is just a fragmentary A. fragilis.
>
> Seriously, whoever edited these (the acknowledgements suggest Spencer Lucas)
> was asleep at the wheel or just didn't care. I'd be very interested to know
> how the claimed peer review by Lucas, Hunt, Foster and (the one who wisely
> chose to remain) Anonymous went down.
>
> References- Dalman, Paulina-Carabajal and Currie, 2012. A new large-bodied
> theropod dinosaur from the Upper Morrison Formation (Late Jurassic,
> Tithonian) of Colorado. Journal of Vertebrate Paleontology. Program and
> Abstracts 2012, 84.
>
Jurassic (Tithonian) Morrison Formation of Colorado, USA. Volumina Jurassica.
12(2), 159-179.
>
> Dalman, 2014b. New data on small theropod dinosaurs from the Upper Jurassic
> Morrison Formation of Como Bluff, Wyoming, USA. Volumina Jurassica. 12(2),
> 181-196.
>
> Mickey Mortimer
>
> ----------------------------------------
>> Date: Mon, 15 Dec 2014 12:51:39 -0800
>> From: bcreisler@gmail.com
>> To: dinosaur@usc.edu
>> Subject: Small theropod dinosaurs from Morrison Formation of Como Bluff,
>> Wyoming (free pdf)
>>
>> Ben Creisler
>> bcreisler@gmail.com
>>
>> A new paper in open access:
>>
>> Sebastian G. Dalman (2014)
>> New data on small theropod dinosaurs from the Upper Jurassic Morrison
>> Formation of Como Bluff, Wyoming, USA
>> Volumina Jurassica 12 (2): 181-196
>> DOI : 10.5604/17313708 .1130142
>> https://www.voluminajurassica.org/volumina/article/view/171/151
>>
>>
>> In 1879, Othniel C. Marsh and Arthur Lakes collected in the Upper
>> Jurassic Morrison Formation Quarry 12 at Como Bluff, Wyoming, USA,
>> several isolated axial and appendicular skeletal elements of small
>> theropod dinosaurs. Since the discovery the specimens remained
>> unnoticed for over a century. The skeletal remains of small theropods
>> are rare at Como Bluff and throughout the Morrison Formation. Their
>> bones are d
>
>> the bones of large-bodied theropods. The bones of small theropods
>> described here were found mixed with isolated crocodile teeth and
>> turtle shells. Comparison of the skeletal materials with other known
>> theropods from the Morrison Formation reveals that some of the bones
>> belong to a very small juvenile Allosaurus fragilis and Torvosaurus
>> tanneri and also to a new ceratosaur taxon, here named Fosterovenator
>> churei, whereas the other bones represent previously unidentified
>> juvenile taxa of basal tetanuran and coelurid theropods. The discovery
>> and description of these fossil materials is significant because they
>> provide important information about the Upper Jurassic terrestrial
>> fauna of Quarry
>> unidentified theropod taxa in the Morrison Formation indicates that
>> the diversity of basal tetanuran and coelurid theropods may have been
>> much greater than previously expected. Although the fossil material
>> here described is largely fragmentary, it is tenable that theropods of
>> different clades co-existed in the same ecosystems at the same time
>> and most likely competed for the same food sources.
>>
>> ===
>