13.7.18 0 comentarios

Diversidad de tortugas pleurodiras de Lo Hueco en el XVI Annual Meeting de la EAVP


Siguiendo con la recopilación de trabajos tortuguiles presentados por el Grupo de Biología Evolutiva de la UNED en el XVI encuentro anual de la EAVP, hoy toca el turno de aquel correspondiente al registro de Bothremydidae de Lo Hueco (Cuenca).

El resumen es el siguiente:

Bothremydidae is the best represented group of turtles in the coastal and freshwater Upper Cretaceous sites of southwestern Europe. Several members of Bothremydini have been identified in the Campanian-Maastrichtian record of this area. Rosasia soutoi is only known in the Portuguese record. Several taxa so far restricted to the French record were described: Polysternon provinciale, Elochelys perfecta and Foxemys mechinorum. Polysternon atlanticum was defined in the Spanish upper Campanian site of Laño (Burgos), being unknown outside of this locality. The only species recognized in more than one country is Iberoccitanemys convenarum. It was defined by a shell from the upper Maastrichtian of Haute-Garonne (France), having been subsequently recognized in Central Spain by several well-preserved complete and partial shells from the upper Campanian-lower Maastrichtian site of Lo Hueco (Cuenca), and by isolated remains from the upper Campanian site of Armuña (Segovia).
Besides the fossils attributed to Iberoccitanemys convenarum, a plastron of a second bothremydid was found in Lo Hueco, this site being the only one in Europe where the synchronous and sympatric coexistence of two bothremydids is currently recognized. However, the limited information so far available only allowed its preliminary identification as an indeterminate member of Foxemydina.
Several unpublished remains from Lo Hueco, attributable to that second form, are presented here. This study allows its accurate systematic attribution, being recognized as Foxemys mechinorum, and, therefore, expanding both the knowledge about the diversity of Bothremydidae in the Spanish record and the paleobiogeographical distribution of this taxon so far exclusively recognized in France.

Esta presentación está relacionada con una publicación que ha sido recientemente publicada, y que fue comentada aquí.

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12.7.18 0 comentarios

Barionicinos de Morella en el XVI Annual Meeting de la EAVP


Continuamos con los trabajos presentados en el último Annual Meeting de la EAVP por miembros del Grupo de Biología Evolutiva de la UNED, nos centramos en la comunicación sobre los dinosaurios terópodos de Morella (Castelón, España). En el congreso se presentó el estudio de un conjunto de restos postcraneales, que incluyen una vértebra cervical, fragmentos de dos fémures y una tibia parcial, recogidos en niveles del Barremiense superior de la Formación Arcillas de Morella y que presentan una combinación de características compatible con los espinosáuridos barionicinos.

El resumen es el siguiente:

Megalosauroid theropods are a relatively diverse clade of basal tetanurans with a worldwide distribution. The clade includes piatnitkysaurids, megalosaurids and spinosaurids. The latter are especially well-represented in Cretaceous strata of Africa, South America, and Asia, but also in Europe, mainly in England, Portugal and Spain. Here, new postcranial remains of spinosaurid dinosaurs from the upper Barremian Arcillas de Morella Formation of Spain are described. These elements correspond to a posterior cervical vertebra, a right femur, a proximal fragment of a right femur, and a partial left tibia collected in three sites within the Mas de la Parreta Quarry at Morella (Castellón province, Spain). These remains present a combination of characters compatible with the clade of spinosaurids Baryonychinae, including the cervical vertebra with neural spine low and transversely thin and elongated zygapophyses and epipophyses. Comparison with elements assigned to Baryonyx indicates some differences between the remains from Morella and those of this genus described in the Lower Cretaceous of England, including the less ventral extension of the lateral femoral condyle relative to the medial one and the much less anteroposteriorly compressed femoral proximal end. Based on some identified differences, especially evident on the femora, the specimens from Morella can be confidently referred to a baryonychine distinct from Baryonyx. These new specimens support the previously proposed hypothesis on the presence of baryonychines in the eastern Spain and add information for the knowledge of the diversity and distribution of this clade in the Lower Cretaceous of the Iberian Peninsula.

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11.7.18 0 comentarios

El cráneo de Pelecanimimus en el XVI Annual Meeting de la EAVP


Durante el desarrollo del XVI Annual Meeting de la EAVP, los dinosaurios terópodos tuvieron un pequeño hueco entre tanto Sauroposium y Crocoposium. Durante el último día del congreso, tuvo lugar la sección "Ornithoscelida", donde se comunicaron charlas y póster tanto de terópodos como de ornitisquios. En esta sesión, Elena Cuesta, miembro del GBE, participó con una charla sobre la osteología craneal de Pelecanimimus, mostrando además resultados del primer escáner en 3D que se realiza en este ejemplar. Aunque el trabajo es preliminar ya se muestran resultados interesantes como que Pelecanimimus tiene varias sinapomorfías de Ornithomimosauria y que muestra una serie de autapomorfías ligadas a su dentición, como una dentario sin desviación anteroventral o la presencia de numerosos dientes en ambas mandíbulas.

Este es uno de los primeros trabajos sobre este maravilloso ejemplar, que aún tiene mucho que mostrarnos. Para más información sobre esta ponencia, aquí os dejamos el resumen (en inglés):

Pelecanimimus polyodon was discovered in 1993 in the Spanish Barremian fossil site of Las Hoyas, being the first ornithomimosaurian described in Europe. So far, there is no detailed description of the holotype of Pelecanimimus that is composed by the anterior half of an articulated skeleton that preserves evidence of soft-tissues as a soft occipital crest and a gular structure.

A detailed osteological description of the skull of Pelecanimimus has been carried out, and its features have been compared with those of other ornithomimosaurian. A CT scan and 3D reconstruction have allowed to decipher some features not previously available.

Pelecanimimus shares with other ornithomimosaurs an enlogated premaxilla, a sharp posterior margin of the maxilla, a well-developed jugal ramus of palatal, a hypertrophied prefrontal, and a parasphenoid bulba. However, Pelecanimimus also have several primitive features such as a subnarial foramen, a premaxillary process not reaching the antorbital fossa and a pneumatic recess in the anterior ramus of jugal. Undoubtedly, the most striking feature of Pelecanimimus is the presence of approximately 200 premaxillary, maxillary and dentary teeth, present only also in Nqwebasaurus.

Over the last 25 years, the known diversity of the ornithomimosaurs has increased throughout the world. The placement in context of Pelecanimimus features in current phylogenetic proposals is especially interesting to shed light on the feeding behaviour of Ornithomimosauria.
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10.7.18 0 comentarios

Neuroanatomía de Lohuecosuchus megadontos en el XVI Annual Meeting de la EAVP


Dentro del simposio acerca de la evolución de los crocodilomorfos que tuvo lugar en el pasado XVI Annual Meeting de la EAVP, A. Serrano Martínez presentó una comunicación describiendo las cavidades internas del cráneo de Lohuecosuchus megadontos, especie procedente del yacimiento conquense de Lo Hueco. A partir de las reconstrucciones de dichas cavidades, se pudieron también realizar una serie de mediciones para estimar algunas de las capacidades neurosensoriales y cognitivas de este animal. Aquí el resumen:

The Campanian-Maastrichtian fossil site of Lo Hueco (Cuenca,Spain) has yielded abundant remains of eusuchian crocodylomorphs. Two species have been recently defined on the basis of specimens found at Lo Hueco: Agaresuchus fontisensis and Lohuecosuchus megadontos. They are members of the clade Allodaposuchidae, which comprises exclusively European species and represents one of the closest outgroups to Crocodylia.

The holotype of Lohuecosuchus megadontos is a nearly complete skull. We CT scanned it and reconstructed all its inner cavities in three dimensions. Although the specimen has undergone some deformation during diagenesis, its endocranial anatomy was amenable to digital reconstruction.

The brain and inner ear cavities, the nervous and vascular canals, as well as the morphology of the tympanic and pharyngotympanic systems and of the paranasal sinuses were compared to those of extinct and extant eusuchians, most of them belonging to the three main lineages of Crocodylia. The presence of several plesiomorphic character-states for Eusuchia, such as a flat caudodorsal surface of the cerebrum, huge lateral expansions of the intertympanic recess and a long medial pharyngeal recess, is consistent with Lohuecosuchus megadontos being an early-branching eusuchian.

The inner skull cavities of Lohuecosuchus megadontos were also quantified and analyzed to evaluate its sensory and cognitive capabilities. Our work suggests that Lohuecosuchus megadontos had neurosensorial capabilities similar to those of extant crocodilians, such as an acute sense of olfaction and a hearing most sensitive to low frequencies.

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9.7.18 0 comentarios

Cosas que huelen a Camptosaurus en el XVI Annual Meeting de la EAVP


Hace unos días se presentaron en el XVI Annual Meeting de la European Association of Vertebrate Paleontologist (EAVP), los restos apendiculares y axiales hallados en tres yacimientos enclavados en la orla mesozoica portuguesa y pertenecientes a tres nuevos individuos de ornitópodos anquilopollexios.

Los resultados preliminares presentados en este congreso corroboran que la composición de ornitópodos no estiracosternos del Jurásico Superior ibérico está compuesta al menos por dos formas, una de ellas exclusiva del este registro europeo como es Draconyx loureiroi y otra estrechamente relacionada con alguna de las especies conocidas del género Camptosaurus, pero que, hasta el momento, es difícil de definir debido a lo fragmentario y, por ende, no diagnóstico material fósil conocido.

Aquí va el resumen:

The most common medium to large-sized ornithopod dinosaurs in the Late Jurassic are non-styracoste- rnan ankylopollexians. The ankylopollexian record from the Upper Jurassic of Portugal is not well-known and mainly based on fragmentary material from few fossil-sites located in the Lusitanian Basin. To date the presence of two species have been documented: Draconyx loureiroi and Camptosaurus aphanoecetes. In this context ankylopollexians discoveries in the Lusitanian Basin are noteworthy. Here additional material from three new localities is presented. Two localities have provided a set of well-pre- served caudal vertebrae, whereas a third locality have just provided an isolated femur. The former specimens (SHN 075 and SHN 074) come from the Sobral Formation at Atalaia (Lourinhã) and Praia da Amoreira-Porto Novo Formation at Atouguia da Baleia (Peniche) late Kimmeridgian-early Tithonian and late Kimmeridgian in age, respectively. The isolated femur [SHN(JJS) 073] comes from the locality of Peralta (Lourinhã. Sobral Formation, late Kimmeridgian-early Tithonian in age). Due to its fragmentary nature, the caudal vertebrae reported here cannot be assigned to none of the taxa described in the present-day Portuguese fossil record, and given the absence of diagnostic features are considered as Ankylopollexia indet. The femur from Peralta resembles those of Camptosaurus, but any autapomorphic feature can be con rmed, and lacks the autapomorphic character combination of the femur of Draconyx loureiroi. Therefore, the femur is here better to referred to Ankylopollexia indet. The new occurrences of non-styracosternan ankylopollexians indicates that medium to large-sized ornithopods were common dwellers during the Late Jurassic of southwestern Europe.

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6.7.18 0 comentarios

Las tortugas de Algora en el XVI Annual Meeting de la EAVP


Como fue indicado aquí, varios investigadores del Grupo de Biología Evolutiva de la UNED defendieron algunos de sus trabajos recientes en el XVI encuentro anual de la EAVP (European Association of Vertebrate Palaeontologists), celebrado hace unos días en la localidad portuguesa de Caparica.

Uno de estos trabajos aludía a los resultados recientemente obtenidos en relación a los proyectos de investigación en proceso sobre la fauna del yacimiento de Algora (Guadalajara) y, más específicamente, en aquellos centrados en los nuevos datos sobre Algorachelus, el taxón más común en ese yacimiento.

El resumen es el siguiente:

Several Gondwana lineages of the crown Pleurodira reached Europe through diachronic Mesozoic and Cenozoic dispersion events. The oldest pleurodiran turtle known in Laurasia is the Bothremydid Algorachelus peregrinus. It was defined in the uppermost middle-lowermost upper Cenomanian site of Algora (Guadalajara, Central Spain), having subsequently been recognized in the middle Cenomanian locality of Nazaré (Central Portugal).
The first systematic excavation of relatively long duration carried out in Algora has recently been performed. As a consequence, abundant material of Algorachelus peregrinus was found. The new material analyzed here corresponds to several complete or almost complete and very well-preserved shells, including the most complete, as well as abundant articulated remains of both the carapace and the plastron. The abundance of remains allows the analysis of the general disarticulation patterns experienced by the shells of this littoral form. This study also allows the identification and characterization of several pathologies. In addition, it also improves the knowledge about the anatomy and intraspecific variability of this form.
This new information allows the evaluation of the validity of other Cenomanian bothremydids, both from Middle East and from North America. Thus, Algorachelus is identified in these regions, being represented in both the early or middle Cenomanian of Palestine, and in the uppermost Cenomanian of Utah. A different species is identified in each of the three continents where the genus Algorachelus is identified. Therefore, close biogeographical relationships are recognized, evidencing a relative fast dispersal event, corresponding to the oldest identified for a Gondwanic lineage of Pleurodira in Laurasia.

Esta presentación está relacionada con un trabajo de reciente publicación y que fue comentado aquí.
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2.7.18 0 comentarios

GBE en el XVI Annual Meeting de la EAVP


Durante la semana pasada, del 26 de Junio al 1 de Julio, tuvo lugar el XVI Annual Meeting de la EAVP (European Association of Vertebrate Palaeontologists) en la ciudad portuguesa de Caparica, en la Facultad de Ciencias y Tecnología de la Universidad Nova de Lisboa. El congreso abrió sus puertas con dos workshops, uno de fotogrametría y otro de morfometría geométrica, a los que siguieron una serie de presentaciones cortas para promover la visibilización LGBTQIA+ en ciencia y exposiciones museísticas, y una segunda edición del workshop acerca de las desigualdades de género y los estereotipos atribuidos a las mujeres en la ciencia, y concretamente en la paleontología.

Ya dentro del propio congreso, cabe destacar la gran afluencia a los tres simposios que formaron el núcleo del congreso: Evolución de crocodilomorfos, microvertebrados cuaternarios y dinosaurios saurópodos. Finalmente, durante el fin de semana se llevaron a cabo las dos salidas de campo, a los Jurásicos de la Cuenca Lusitánica y a la Cuenca del Algarve.


En esta ocasión, el Grupo de Biología Evolutiva de la UNED participó de forma masiva, enviando los siguientes trabajos:
Enhorabuena al grupo de paleontologia de la Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa (FCT NOVA) por la magnífica organización... y nos vemos en el XVII EAVP del año que viene en Bruselas....