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Re: [dinosaur] North American Ornithomimids Pedal Unguals + Journal of Iberian Geology 44(1) (free pdfs)



Regarding the first paper:

Chase Doran Brownstein (2018)
Rebuttal of McFeeters, Ryan and Cullen, 2018, 'Positional variation in pedal unguals of North American ornithomimids (Dinosauria, Theropoda): A Response to Brownstein (2017)'.
Vertebrate Anatomy Morphology Palaeontology 6: 68-72
DOI 10.18435/vamp29340
https://journals.library.ualberta.ca/vamp/index.php/VAMP/article/view/29340

The Arundel Clay of Maryland is among the only Early Cretaceous terrestrial units known from eastern North America. Research on some theropod dinosaur bones from this layer has indicated the presence of two ornithomimosaur taxa in the assemblage. However, a recent paper discussed issues with the definite assignment of any of these unguals to Ornithomimosauria and suggested that morphological differences originally interpreted to be indicative of the presence of two ornithomimosaurs could be explained by positional variation. Here, I show that substantial evidence persists for the presence of two ornithomimosaurs in the Arundel Clay assemblage, even considering the recent description of positional variation in ornithomimosaur pedal unguals. Furthermore, the argument against the confident assignment of these unguals to ornithomimosaurs is shown to be based on oversimplified comparisons that do not take into account the combination of features in the Arundel specimens that allow for their assignment to that clade. Although several small points made in the initial paper describing the Arundel specimens are incorrect or unsubstantiated, the differences between the Maryland unguals are outside the spectrum of positional variation and are indicative of the presence of two ornithomimosaurs in the Arundel Clay assemblage.

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Bradley McFeeters , Michael Ryan & Thomas Cullen (2018)
Response to Brownstein (2018) 'Rebuttal of McFeeters, Ryan and Cullen, 2018'.
Vertebrate Anatomy Morphology Palaeontology 6: 73-74
DOI 10.18435/vamp29343
https://journals.library.ualberta.ca/vamp/index.php/VAMP/article/view/29343





On Sat, May 26, 2018 at 10:31 AM, Ben Creisler <bcreisler@gmail.com> wrote:



Ben Creisler
bcreisler@gmail.com


Some recent and not so recent papers that are now in revised form and with free pdfs:

I posted an earlier version of this paper this week. However, it has now been retitled and revised. Here is the revised version at the same link:

free pdf

Bradley McFeeters, Michael J. Ryan & Thomas M. Cullen (2018)
Positional Variation in Pedal Unguals of North American Ornithomimids (Dinosauria, Theropoda): A Response to Brownstein (2017).
Vertebrate Anatomy Morphology Palaeontology 6: 60-67


Positional variation is documented in ornithomimid pedal unguals from the Dinosaur Park and Horseshoe Canyon Formations of Alberta, Canada, and characters for identifying the position of isolated ornithomimid pedal unguals are discussed. Ungual morphology has been used recently to argue for the coexistence of two distinct ornithomimosaurs, a basal taxon and distinctly more derived taxon, in the Early Cretaceous Arundel Clay of Maryland, USA. However, these conclusions are based on misconceptions of the morphology and positional variability of ornithomimosaur unguals. Some characters previously cited as diagnostic of ornithomimosaur unguals are not actually observed in this clade, or are more homoplastically distributed among theropods. Other characters proposed to distinguish between the two pedal ungual morphs in the Arundel Clay material are shown in the Albertan ornithomimid material to consistently distinguish the different ungual positions within the pes of one individual. Claims of multiple distinct ornithomimosaur taxa in the Arundel Clay are premature, as the two pedal ungual morphotypes more likely represent positional variation in a single taxon.


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Theses papers were posted earlier in advance publication form. Some were free but most were not.Â
The March 2018 issue of Journal of Iberian Geology now has all free pdfs. Here are the vertebrate articles with pdf links:

Journal of Iberian Geology 44(1)

Palaeodiversity and evolution in the Mesozoic world


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Borja Holgado & Maite SuÃer (2018)
Palaeodiversity and evolution in the Mesozoic world.
Journal of Iberian Geology 44(1): 1-5

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A. Alonso, J. M. Gasca, P. Navarro-LorbÃs, C. Rubio & J. I. Canudo (2018)
A new contribution to our knowledge of the large-bodied theropods from the Barremian of the Iberian Peninsula: the "Barranco del Hocino" site (Spain).
Journal of Iberian Geology 44(1): 7-23

Introduction

Barranco del Hocino-1 is a new fossil site located near Estercuel, Teruel province, Spain. The fossil site is located geologically within the Oliete sub-basin, in the Blesa Formation (Barremian in age). Barranco del Hocino-1 shows a diverse assemblage of tetrapod vertebrates similar to other sites in the Blesa Formation.

Materials and methods

Six isolated teeth belonging to Theropoda have been found. A study of their qualitative and quantitative characters, along with statistical (DFA) and cladistic analyses, enable us to identify four different dental morphotypes.

Results

These morphotypes belong to separate tetanuran theropod taxa. One is related to Spinosauridae. The other morphotypes show affinities with non-spinosaurid tetanurans, probably related to Carcharodontosauria.

Conclusions

The results are congruent with the known theropod record of the Iberian Peninsula and western Europe. This work is a new contribution to what is known of the palaeobiodiversity and distribution of large-bodied theropods from the Barremian of the Iberian Peninsula.

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Kamila L. N. Bandeira, Arthur S. Brum, Rodrigo V. PÃgas, Giovanne M. Cidade, Borja Holgado, Andrà Cidade & Rafael Gomes de Souza (2018)
The Baurusuchidae vs Theropoda record in the Bauru Group (Upper Cretaceous, Brazil): a taphonomic perspective.
Journal of Iberian Geology 44(1): 25-54


Purpose

The Bauru Group is worldwide known due to its high diversity of archosaurs, especially that of Crocodyliformes. Recently, it has been suggested that the Crocodyliformes, especially the Baurusuchidae, were the top predators of the Bauru Group, based on their anatomical convergence with theropods and the dearth of those last ones in the fossil record of this geological group.

Methods

Here, we erect the hypothesis that assumption is taphonomically biased. For this purpose, we made a literature survey on all the published specimens of Theropoda, Baurusuchidae and Titanosauria from all geological units from the Bauru Group. Also, we gathered data from the available literature, and we classified each fossil find under a taphonomic class proposed on this work.

Results

We show that those groups have different degrees of bone representativeness and different qualities of preservation pattern. Also, we suggest that baurusuchids lived close to or in the abundant flood plains, which explains the good preservation of their remains. Theropods and titanosaurs did not live in association with such environments and the quality of their preservation has thus been negatively affected.

Conclusions

We support the idea that the Baurusuchidae played an important role in the food chain of the ecological niches of the Late Cretaceous Bauru Group, but the possible biases in their fossil record relative to Theropoda do not support the conclusion that baurusuchids outcompeted theropods. Rather, this taphonomic bias must be tackled first, which previous studies have not regarded.

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J. Parrilla-Bel & J. I. Canudo (2018)
New longirostrine crocodylomorph remains from the Blesa Formation (Barremian) in the Iberian Peninsula (Spain).
Journal of Iberian Geology 44(1): 55-66

Purpose

Crocodylomorpha has been a highly morphologically and ecologically diverse clade over time. During the Mesozoic and Cenozoic, several crocodylomorph lineages colonized the marine environment; however, by the late Early Cretaceous the extinction of Thalattosuchia and the origination of new marine forms occur, and the âMiddleâ Cretaceous is a period of time where marine crocodylomorphs are poorly known. Here we describe two rostrum fragments (MPZ 2016/78 and MPZ 2016/79) collected in the upper part of the Blesa Formation (Barremian, Lower Cretaceous) in Teruel (Spain). The âUpperâ Blesa Fm has been interpreted as a coastalâtransitional depositional environment.

Results

The specimens correspond to long-snouted crocodylomorphs. MPZ 2016/78 is the left half of a fragmentary rostrum with heterodonty in dentition size, M4? and M5? being the largest alveoli. This suggests that it belongs to a crocodylomorph with a generalist diet. By contrast, MPZ 2016/79 is a fragmentary right half of a more gracile and slender long rostrum. It is homodont in size, with several small teeth, common in animals specialized for ichthyophagy.

Conclusions

MPZ 2016/78 and MPZ 2016/79 have been assigned to Crocodylomorpha indet. This new crocodylomorph material, together with the fossil remains of marine vertebrates previously found in the same region (plesiosaurs, chelonians, osteichthyans, chondrichthyans and a new crocodylomorph), suggests that the âUpperâ Blesa Formation was a coastal zone with a great wealth of fauna, making it an interesting area for the study of Barremian marine vertebrates.


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Flavio Bellardini, Mattia A. Baiano, Francisco Barrios, Borja Holgado & Rodolfo A. Coria (2018)
New Titanosauria (Dinosauria, Sauropoda) remains from the Upper Cretaceous (Plottier Fm) of the southern NeuquÃn Basin (Patagonia, Argentina).
Journal of Iberian Geology 44(1): 75-84

Purpose

New sauropod remains (MCF-PVPH-889, MCF-PVPH-899, and MCF-PVPH-900) collected from the Plottier Fm (ConiacianâSantonian) in the south-west of the NeuquÃn Basin, are here reported. The materials proceed from a fluvial outcrop composed by siltstone and fine sandstone, whose fossil record is known for large-sized sauropod taxa.

Methods

Due to the fragmentary condition of the dorsal ribs and the tibia, we focus the description mainly on the femur and the fibula.

Results

The specimen MCF-PVPH-889 consists of partially associated postcranial elements represented by a left femur and three fragmentary dorsal ribs of a Titanosauria indet. A right fibula (MCF-PVPH-900) represents another titanosaurian element, while a proximal portion of a right tibia (MCF-PVPH-899) of a smaller individual than others is here referred to as a Sauropoda indet. MCF-PVPH-889 and MCF-PVPH-900 share some features with other titanosaurian taxa (e.g., a femur with medial deflection of the proximal end and elliptical mid-shaft cross-section, a fibula with slightly sigmoidal shaft and well-developed lateral tuberosity) like in Epachthosaurus and Antarctosaurus. However, the femur, with a poorly developed lateral bulge and a relatively low head, and a fibula, with a slender and nearly straight proximal third of the shaft, represent plesiomorphic conditions among titanosaurians.

Conclusions

The new remains represent a new sauropod record from the Plottier Fm (Upper Cretaceous). Nevertheless, due to the lack of more diagnostic elements, we prefer to consider the specimens MCF-PVPH-889 and MCF-PVPH-900 as Titanosauria indet, and the MCF-PVPH-899 as Sauropoda indet. This new evidence expands the Coniacian sauropod record of the NeuquÃn Basin and contributes, in some measure, to our knowledge of the stratigraphical distribution of sauropods from the Patagonian Upper Cretaceous fossil-bearing levels.


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A. de Celis, I. NarvÃez & F. Ortega (2018)
Pelvic and femoral anatomy of the Allodaposuchidae (Crocodyliformes, Eusuchia) from the Late Cretaceous of Lo Hueco (Cuenca, Spain).
Journal of Iberian Geology 44(1): 85-98


Purpose

The fossil record of postcranial remains assigned to Allodaposuchidae is currently sparse. However, the Late Cretaceous paleontological site of Lo Hueco (Cuenca, Spain), from where two new taxa of allodaposuchid have been described, has yielded numerous postcranial remains assignable to this clade. Among them, the large amount of pelvic and femoral material is notable, providing the opportunity to study these allodaposuchid elements and assess their morphological similarity with other eusuchian remains.

Methods

The comparison with extant crocodylians was accomplished using traditional morphometric techniques, whereas the comparison with other fossils and establishment of morphotypes was done using morphological criteria.

Results

The results of the cluster and principal components analyses show morphological differences between extant crocodylians and allodaposuchids from Lo Hueco, allowing the segregation of these lineages. The similarities found between the pelvic and femoral remains from Lo Hueco, and those referred to Allodaposuchus precedens and other putative allodaposuchids from the Iberian Peninsula, allows referral of these remains to allodaposuchids. The differences found among the femoral and pelvic remains of Lo Hueco enables us to recognize two morphotypes per each element.

Conclusions

This study allows a better understanding of allodaposuchid postcranial elements that were previously poorly known. The ilia, ischia and femora from Lo Hueco allodaposuchids are distinct from those of other crocodylian lineages. Finally, the fact that there are two morphotypes per each element at Lo Hueco is congruent with the presence of two different allodaposuchids at the site.


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ElÅbieta M. Teschner, P. Martin Sander & Dorota Konietzko-Meier (2018)
Variability of growth pattern observed in Metoposaurus krasiejowensis humeri and its biological meaning.
Journal of Iberian Geology 44(1): 99-111

Purpose

Histological studies on temnospondyl amphibian bones remain rare. A systematic revision of the histology was applied for the purpose of testing the histovariability in the humeri and becoming new information about the growth pattern.

Methods

The present study includes 12 humeri of Metoposaurus krasiejowensis, which originate from the Late Triassic clay pit near KrasiejÃw, southwestern Poland. The specimens were scanned with a microCT and the histological thin-sections have been obtained with the standard petrographic method.

Results

The evaluation of the studied bones shows a uniform growth series resulting in one morphotype. Strikingly, the histological analysis reveals a greater diversity with two different histotypes: Histotype I shows a distinct differentiation between alternating zones and annuli with poor to moderate vascularization and increase of bone remodeling during growth. Histotype II does not show any distinct zones and annuli but is characterized by a high vascularization and fast growth coexisting with an extensive bone remodeling.

Conclusions

Based on these two different growth patterns, several hypotheses can be established: The specimens do not show any pattern of histological variation; humeri represent a taxonomic diversity; the analyzed Metoposaurus bones stem from two different populations separated by space and; or time or sexual dimorphism.


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Ignacio DÃaz-MartÃnez, Silvina de Valais & Carlos CÃnsole-Gonella (2018)
New sauropod tracks from the Yacoraite Formation (MaastrichtianâDanian), Valle del Tonco tracksite, Salta, northwestern Argentina.
Journal of Iberian Geology 44(1): 113-127


Purpose

A relative long sauropod trackway and hundreds of varied indeterminate dinosaur tracks, many of them probably related to ornitischians, were found many years ago in the Valle del Tonco tracksite (Salta, northwestern Argentina). This sauropod trackway is now described and analyzed in an updated context.

Methods

Ichnological analyses were mainly conducted during fieldwork. Fossiliferous surface was mapped and digitalized in order to recognize the track shape and their distribution.

Results

The trackway-bearing surface belongs to an inverted section from the uppermost Cretaceous Caliza Amblayo Member, the lower unit of the Yacoraite Formation in this area. The sauropod trackway is moderate to poorly-preserved and includes twelve manusâpes imprint sets as convex hyporelief (natural casts). The heteropody is high and the PTR index indicates a medium category for the trackway gauge. The pes tracks, longer than wide, have subtriangular posterior edge and a general rhomboidal shape, lacking a lateral notch, and the digit-claw traces are laterally located. The manus tracks are subrounded to rectangular with at least two short, posteriorly oriented digit imprints.

Conclusions

Their main features and preservation/weathering do not allow a precise assignment to a particular ichnotaxon. Taking into account the best-preserved CampanianâMaastrichtian sauropod pes tracks, two different general shapes can be differentiated: the Campanian Humaca shape (Bolivia) and the Maastrichtian Fumanya shape (Spain). The Valle del Tonco pes prints show similarities with the Fumanya shape. The presence of two pes track shapes in this age suggests that at least two different titanosaur feet morphology were present in the uppermost Cretaceous.

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