Seeking criticism/discussion - Translation of Cruzado-Caballero et al., 2005 (New evidence of lambeosaurine hadrosaurs [...])

[Nick Gardner <nick.gardner@gmail.com>]

I finished this translation a day or so ago with the aid of two and
half years of Spanish, Babelfish, and some assistance from various
people, I was able to get this hashed out over a few days, I'm looking
for someone to point out if there are any glaring errors, and
especially those that don't stick out, I know in some places it feels
a little rough, so if anyone would like to correct a mistake
publically, please do so.

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Introduction

The discovery of remains of hadrosaurs in Europe goes back to the end
of the nineteenth century and the beginning of the twentieth century,
when with the description of Orthomerus dolloi Seeley 1883, Trachodon
cantabrigiensis Lyddeker 1888 and Telmatosaurus transsylvanicus
(Nopsca 1900), of which only Telmatosaurus transsylvanicus conserves
taxonomic assignment.  The other taxa are considered at present nomina
dubia (Brinkmann, 1988; Weishampel and Horner, 2004). Most recently,
Casanovas-Cladellas et al. (1993) described a new hadrosaur from the
Maastrichtian of Lleida (Pararhabdodon isonensis Casanovas-Cladellas
et al. 1993). The type specimen is composed of cranial and postcranial
material, the holotype a cervical vertebra. At present, its systematic
position is disputed in the clade Euhadrosauria.  Casanovas et al.
(1999) considered it to be a derived form included within the
lambeosaurines, however, other authors place in a more basal position,
considering that true lambeosaurines have not been found in Europe
(Head, 2001).

Traditionally, it is considered that the European hadrosaurs in the
Late Cretaceous pertained to a primitive clade preserved by endemism
in the European archipegalo (Weishampel et al., 1993). However, the
possible presence of lambeosaurines (Casanovas et al., 1999;
López-Martínez et al., 2001) draws another scenario implicating also
the migration from Asia from North America, or also the vicarious
evolution in Europe.  In order to be able to further the two
paleobiogeographical hypotheses, it is necessary to first continue
contributing data about the presence of lambeosaurines in Europe and
to study if they are more closely related with Asian or North American
forms.  In this direction, the objective of this work is to describe
first the ilium of a lambeosaurine hadrosaur of the Upper
Maastrichtian of the Península Ibérica.

Geographical and geological context

The locality of Arén is situated in the La Ribagorza district (in the
far Northwest of the Huesca province. Fig. 1). The township bordering
with Cataluña, is separated by the river Noguera. The deposits with
remains of dinosaurs were found west of the urban center very near the
col of Blasi, that gives it name to it. Six levels with dinosaur
remains, numbered Blasi 1 to Blasi 5, have been located. Levels 1-3
were found in the same outcropping, and levels 4-5 to the west of
there, but they are clearly correlated stratigraphically
(López-Martinez et al., 2001). The ilium studied in this work
originates from the Blasi 3 level.

In the township of Arén, it is easy to identify the succession of
formations of the Tremp Group of the Cuenca de Tremp. The continental
facies fundamentally are fluvial and are scarcely influenced by the
coastline restricted to the small part of the Group, the Conques
Formation (Oms and Canudo, 2004). In this formation, grey, orange and
brown colored lutites predominate interposed with levels of sandstone
and microconglomerates with vertebrate fossils. In one of these
detritic levels located near the base of the formation (Unit Arén 4)
is where Blasi 3 is located (López-Martínez et al., 2001).
Lithologically, Blasi 3 is massive grey calcareous sandstone with
vertical traces of crustaceans. Its approximate yield is 1 meter,
containing the remains of vertebrates in all of the fossil levels.

Blasi 3, as well as the rest o the deposits of Blasi, is of the late
Maastrichtian considering their micropaleontological content and its
correlations to the level of the river basin (López-Martinez et al.,
2001), confirmed by a recent magnetostratigraphical study (Oms and
Canudo, 2004). The remains have been found in an area of about 40
square meters, belonging the majority to hadrosaur ornithopods. Some
of the remains from Blasi 3 are spectacular, an example is the eight
caudal vertebrae that are in anatomical connection. Also, the isolated
teeth of theropods have been recovered (López-Martínez et al., 2001;
Torices et al., 2004).

Systematic Paleontology

Dinosauria Owen 1842
Ornithischia Seeley 1888
Ornithopoda Marsh 1881
Hadrosauridae Cope 1869 (sensu Weishampel et al., 1993)
Lambeosaurinae Parks 193
Lambeosaurinae indet. (Fig.2)

Material

A right ilium (MPZ 2005/90) deposited in the Museo Paleontológico de
la Universidad de Zaragoza.

Origin and Age

Blasi 3, Arén (Huesca); Tremp Group, Conques Formation, late Maastrichtian.

Description

MPZ 2005/90 is a complete and well preserved right ilium (Fig.2). Its
general form is lengthened and distinctly compressed laterally. It is
formed by the preacetabular process, the iliac body and the
postacetabular process (Fig.3). The dorsal border of the ilium is
sinuous, with the preacetabular and postacetabular processes curved
laterally, the curvature of the postacetabular process is very marked.

The preacetabular process is lengthened, curved and flattened
lateromedially (length 182 mm). The section is subtriangular with the
ventral border acute and longitudinally dorsoventrally gradually
making the anterior part diminished. In medial view, it presents a
well defined crest deflected in the dorsomedial part and reflected
parallel to the dorsal border, terminating at the end of the
preacetabular process. This process preserves marks of the insertion
nof the muscle Iliotibialis which is very developed at the anterior
end. The preacetabular crack is broadened and observed at an angle of
120 degrees (with origin of point of the inflexion of the crack of the
preacetabular process and measured in the cranial direction, Fig.3).

In medial view, the crest happens to be united to a rim that extends
by all the iliac body, where it is more developed. The iliac body
presents in lateral view a supracetabular process ("antitrochanter")
well developed with a semioval inclined form posteroventrally and with
a straight dorsal border. This process is developed at least until
half of the height of the iliac body.

In the ventral edge is the ischial peduncle, the pubic peduncle, and
the acetabulum; both peduncles are in a lateral position in the
ventral border. Between these peduncles, it is observed a convex
structure in the ventral position proximal to the ischial peduncle,
which has an oval form and beyond the iliac body in lateral view,
locating itself underneath the supracetabular process. The acetabulum
is very deep, and its position is advanced extremely anterior.

The postacetabular process is very developed with a length of 110.9 mm
and presents a subtriangular section, whose caudal end is turned aside
laterally in medial view. The dorsal border is heavy and weakly
convex, while the ventral edge is deeply concave and devoid of a
"brevis shelf". The postacetabular crack is ample and an angle of 140
degrees (with the origin of the point of inflexion of the crack of the
postacetabular process and measuring in the caudal direction, Fig.3).
The major part of the medial side has a planar area with impressions
of small muscular insertion nso the muscle Flexor tibialis externus,
being those of the ventral edge the most marked. Also, there is a
crest in the ventral side that unites the final part of the
postacetabular process with the iliac body, finalizing in the
beginning of the iliac body.

Discussion

The ilium of hadrosaurs (Fig.3) is different from "iguanodontids" in
the presence of a large preacetabular process, which is ventrally
deflected and laterally compressed, a large and projecting
supracetabular process, and a tall and long postacetabular process
with a blade-like form, a massive ischial peduncle, and a short and
slight construction nfo the pubic peduncle (Horner et al., 2004). The
ilium of hadrosaurs are often depressed upon the supracetabular
process, and the preacetabular process is dorsally arched. Within
these, the hadrosaurines present usually a dorsoventrally short ilium,
whereas the lambeosaurines have an ilium that is relatively very tall.
In addition, the lambeosaurines generally have a much more massive
supracetabular crest and sometimes, a strongly arched preacetabular
process (Horner et al., 2004).

The most recent phylogenetic proposals for the large ornithopods
(Horner et al., 2004, Norman, 2004) ultilize some characters of the
ilium. Those are in Iguanodontia the form and length of the
preacetabular and postacetabular processes, the dorsal margin of the
iliac body, and the form of the dorsal edge of the ilium and the
ischial peduncle, whereas for the Hadrosauridae are identified by the
size of the supracetabular processthe ilium-pubis articulation, and
the general form of the postacetabular process.

Following these characters, we can say that the ilium MPZ 2005/90
presents a lengthened preacetabular process (0.38 times the overall
length of the ilium 182:468 mm) and thin, and the postacetabular
process is rectangular and long (0.23 times the length of the ilium,
106.68:468 mm) like hadrosaurs and derived iguanodontids. In addition,
within the hadrosaurs, the proportions of total length/maximal width
(4.17), one can accord to the proportions lambeosaurines (3.31 to
5.05) that they are different from the hadrosaurines (4.44 to 6.83)
(Fig.4 and Table 1). Other lambeosaurine characters are present in the
Blasi 3 ilium are the massive preacetabular process that is placed
near the midheight of the iliac body, and a preacetabular process that
is strongly arched with an angle of 120 degrees (Horner et al., 2004)
in comparison with hadrosaurines, which mainly present a straight
process that is deeply deflected ventrally.

Conclusions

The characters present in MPZ 2005/90 permit inclusion in the
lambeosaurine hadrosaurs, determining it provisionally as
Lambeosaurinae indet. Within the group, it is necessary to continue
investigating the rest of the material which is disposed in the same
deposits, still in preparation, because with the data that we have at
the moment, we cannot get to assign any sort of concrete genera. MPZ
2005/90 contributes new evidence that supports the association of
hadrosaurs in Europe at the end of the Cretaceous cannot be explained
exclusively by the presence of endemism developed in the islands of
the European archipelago. Doubtlessly, there are phylogenetic
primitive taxa like Telmatosaurus which could be relicts of the
primitive fauna, but the discovery of fossils like MPZ 2005/90 could
indicate the migration of modern faunas from other parts of Laurasia.
Nevertheless, it's too soon for proposing from where this migration
took place.

Acknowledgements

The Aragosaurus group of investigation in dinosaurs of the Universidad
de Zaragoza is financed by the Ministerio de Ciencia y Tecnología
(project PIVeCI:CGL 2004-03393), the Gobierno de Aragón Dirección
General de Patrimonio Cultural, and Dirección General de Investigación
y Desarrollo [project "Multidisciplinar Juráscio-Cretácico", Financión
de Grupos Emergentes, 2003-2004]. The excavations inBlasi and the
restoration nof the materials have been subsidized by Gobierno de
Aragón, la Diputación Provincial Huesca y el Ayuntamiento de Arén.
Photographs and plates were made by Zarela Herrera and Isabel
Pérez-Urresti of Servicio de Fotografía paleontológica of the
Universidad de Zaragoza.

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Special thanks to everyone who gave some assistance, no matter how
small- zegh, dinosauricon, dinochick, pedro, angaturama, you guys
helped smooth out some of the words I was having trouble with (COLLADO
LOL~), and especially dinosauricon who caught those really silly
grammar issues this afternoon, I missed; thanks to CrimsonGX,
alteridoS and candrodor - you guys were really the most helpful
overall with your aid when things seemed really wierd and I needed a
native speaker to smooth them out.