Paleoneurología de ornitópodos estiracosternos de Morella en las XXXIX Jornadas de la SEP

Los ornitópodos estiracosternos de la Formación Arcillas de Morella también tuvieron su protagonismo en la sesión de Paleo3D que se celebró durante el desarrollo de las XXXIX Jornadas de la Sociedad Española de Paleontología celebradas en A Coruña. En este sentido la aplicación de técnicas de tomografía computarizada y el posterior modelado en tres dimensiones permitieron acceder al interior de la cavidad endocraneana de uno basicráneos hallados en el yacimiento localizado en el área denominada Mas de Sabaté (Cantera del Mas de la Parreta de Morella) CMP-MS-05. En la comunicación presentada en el congreso se describieron distintas regiones de este endrocráneo, como los hemisferios cerebrales, los bulbos olfatorios, además de el oído interno. Estas estructuras se compararon con las ya conocidas de otros ejemplares de la Formación Arcillas de Morella junto con al de otras formas de ornitópodos. Los resultados obtenidos aportan información relevante sobre distintos aspectos paleontológicos de este grupo de dinosaurios comedores de vegetación. Aquí va el resumen:

We describe the cavities of the neurocranium of a new basal styracosternan ornithopod from the Mas de Sabaté quarry, a rich fossiliferous locality from the upper Barremian Arcillas de Morella Formation (Morella, Castellón, Spain). The neurocranium was scanned applying computed tomography techniques (CAT-scan), which enabled access to new endocranial anatomical information. A 3D model was generated to virtually reconstruct the morphology of the braincase and its internal cavities. As the neurocranium was complete and well-preserved we were able to obtain a very detailed endocast for this specimen. The olfactory bulbs and tracts (cranial nerve I), cerebral hemispheres, pituitary body, dural peak, cerebellum, and the medulla oblongata were identified. Also, a partial inner ear, most of the cranial nerves and main blood vessels like the internal carotid artery or the caudal middle cerebral vein were also identified and reconstructed. In addition, this endocast model was compared with those of other styracosternan specimens from Morella, all of them displaying notable differences in the general shape of the encephalic mass, with the new one being more slender, the size of its dural peak very pronounced (not only compared with the other Morella specimens but also with other ornithopods) and with different relative position of several cranial nerves and differences in morphology and size of the inner ear semicircular canals. These noticeable differences in their endocasts suggest that the specimens from Morella possibly belonged to different taxa and that they might have occupied different ecological niches.

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Más información: 

• Referencia: Ciudad Real, M., Escaso, F., Gasulla, J. M., Ortega, F. Comparative neuroanatomy of a new basal styracosternan ornithopod from the Arcillas de Morella Formation (Castellón, Spain). In Moncunill-Solé, B., Blanco, A., Grandal d’Anglade, A., González Fortes, G., Santos Fidalgo, L., Bao, R. (Eds.), Libro de Resúmenes de las XXXIX Jornadas SEP. Palaeontological Publications 5, 67. 
• Imagen: María Ciudad Real durante su interlocución en la sesión de Paleo3D del congreso.

La pleurodira europea más antigua en las XXXIX Jornadas de la SEP

El grupo de Biología Evolutiva de la UNED defendió, en las XXXIX Jornadas de la Sociedad Española de Paleontología, varios trabajos relativos a algunas de las investigaciones sobre tortugas fósiles actualmente en curso. Entre ellas se incluye el análisis de las primeras formas de Pleurodira registradas en Europa. Para ello, se expusieron los principales resultados relativos al hallazgo de un caparazón de Algorachelus en niveles depositados junto a la transición entre el Cretácico Inferior y el Cretácico Superior, recientemente publicado. El resumen de esta contribución, con el título “Implications of the discovery of a pelomedusoid turtle in the Boundary Marls Unit (Utrillas Group) of Estercuel (Teruel, Spain)”, es el siguiente:

The recent discovery of a turtle shell at La Dehesa mine, in Estercuel (Teruel Province, northeastern Spain) is documented here. This discovery is the first reptile remain recovered in the mine. It corresponds to an articulated partial shell, preserving most of the plastral plates but only some osseous elements of its carapace. However, the internal cast of the other carapacial areas is also recognized. Its discovery occurred in shallow marine deposits of the Boundary Marls Unit of the Utrillas Group, deposited during the late Albian (latest Early Cretaceous) or earliest Cenomanian (earliest Late Cretaceous). Several characters of this shell, especially the presence of mesoplastra and that of the pelvic girdle sutured with the shell allow its attribution to the crown group Pleurodira. It is identified as a representative of Pelomedusoides and, more specifically, attributed to Bothremydidae. This systematic attribution has important paleobiogeographic repercussions, since it represents the oldest evidence of this successful lineage, of Gondwanan origin, outside this region. In fact, it is also the oldest fossil of a pelomedusoid turtle in Laurasia. The precise systematic attribution of this specimen is discussed.

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Más información:

• Referencia: Pérez-García, A., Rubio, C. Implications of the discovery of a pelomedusoid turtle in the Boundary Marls Unit (Utrillas Group) of Estercuel (Teruel, Spain). In Moncunill-Solé, B., Blanco, A., Grandal d’Anglade, A., González Fortes, G., Santos Fidalgo, L., Bao, R. (Eds.), Libro de Resúmenes de las XXXIX Jornadas SEP. Palaeontological Publications 5, 207.

Análisis de la diferenciación morfológica del paladar en cocodrilos en las XXXIX Jornadas de la SEP

Durante las XXXIX Jornadas de la Sociedad Española de Paleontología celebrada en A Coruña varios miembros del Grupo de Biología Evolutiva presentaron el trabajo titulado “Morphological differenciation of the crocodylian palate: an ontogenetic analysis using geometric morphometrics”. En este trabajo se analizó cómo varía la morfología palatal de las especies de cocodrilo actuales desde que son recién nacidos hasta que alcanzan el estadío adulto, utilizando para ello técnicas de morfometría geométrica. Los resultados muestran que el área del paladar que experimenta mayores cambios durante el crecimiento de los cocodrilos es la fenestra suborbital, y que además los tres grandes clados de cocodrilos actuales (Gavialidae, Alligatoridae y Crocodylidae) no se superponen en el morfoespacio desde el estadío juvenil en adelante. Los aligatóridos y crocodílidos recién nacidos parecen ocupar un mismo morfoespacio, pero en su paso hacia el estadío juvenil ocurre un cambio en su ocupación del morfoespacio, diferenciándose. Por último, los análisis de señal filogenética y proyecciones del morfoespacio (phy-PCA, PACA) indican que los juveniles ya presentan una señal filogenética significativa en la morfología del paladar, de modo que ya en el estadío juvenil los paladares de aligatóridos, crocodílidos y gaviales están suficientemente diferenciados entre sí como para ocupar distintas áreas del morfoespacio. A continuación, el resumen completo:

Ontogenetic series of different organisms are occasionally found in the fossil record, and to understand these, paleontologists rely on the studies produced by neontological disciplines on the organisms most closely related to the fossil organisms being studied. In the specific case of crocodylians, recent studies have examined the ontogenetic morphological changes in the cranium of extant species. However, these studies have primarily focused on the dorsal and lateral views of the skull, and thus the ontogeny of the palate has remained largely unexplored and is poorly understood despite the evolutionary relevance of the palatal structure within Eusuchia. Hence, this study analysed the palatal ontogenetic development in extant crocodylians using postnatal series from 23 species comprising a total of 334 craniums from hatchling to adult individuals. A 2D geometric morphometric approach was used, and analyses of morphospace occupation between ontogenetic stages and analysed clades (Alligatoridae, Crocodylidae, Gavialidae) were performed, as well as analyses of the phylogenetic signal present in the shape data across different ontogenetic stages. The results indicate that the most important shape changes occur in the suborbital fenestrae, and also reveal that the three clades do not overlap in the morphospace from the juvenile stage onwards. Pairwise comparisons to test for morphospace occupation indicate that no significant differences were found between alligatorid and crocodylid hatchlings, suggesting the presence of a conserved embryonic region for these clades, in accordance with previous studies. In addition, the phylogenetic signal analyses indicate that there is a significant phylogenetic signal in the shape of the palate of juvenile crocodylians. The results of this study allow us to better understand the palatal ontogeny of crocodylians and enable us to apply this information to ontogenetic series of Crocodyliformes in the fossil record.

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Más información:

• Referencia: de Celis, A., Narváez, I., Ortega, F. Morphological differentiation of the crocodylian palate: an ontogenetic analysis using geometric morphometrics. In Moncunill-Solé, B., Blanco, A., Grandal d’Anglade, A., González Fortes, G., Santos Fidalgo, L., Bao, R. (Eds.), Libro de Resúmenes de las XXXIX Jornadas SEP. Palaeontological Publications 5, 161.

Una de saurópodos titanosaurios de Lo Hueco en las XXXIX Jornadas de la SEP

Los restos apendiculares de un nuevo saurópodo titanosaurio del yacimiento paleontológico de Lo Hueco han sido presentados en una comunicación durante la celebración de las pasadas XXXIX Jornadas de la Sociedad Española de Paleontología celebradas en A Coruña. Este grupo de dinosaurios es el que presenta una mayor y mejor representación de todo el registro fósil extraído en este yacimiento castellanomanchego perteneciente a la Formación Villalba de la Sierra (Cretácico Superior). Los restos presentados en esta comunicación pertenecen a uno de los individuos más completos de los conocidos hasta hora en Lo Hueco. De entre el registro europeo de saurópodos titanosaurios del intervalo Campaniense superior- Maastrichtiense inferior, los restos apendiculares del ejemplar presentados en esta comunicación se corresponden con una de las extremidades posteriores más completas conocidas hasta el momento. De este modo, estos restos apendiculares aportan información de gran relevancia para conocer diversos aspectos paleobiológicos de esta forma cuadrúpeda y permiten ajustar el estatus filogenético de algunos de los conjuntos esqueléticos de saurópodos conocidos en este rico yacimiento del Cretácico Superior europeo. Aquí va el resumen:

Lo Hueco fossil site (Fuentes, Cuenca) was discovered in the upper Campanian-lower Maastrichtian levels of the Villalba de la Sierra Formation, at the southwestern branch of the Iberian Ranges. The site is a multitaxic bonebed that has yielded over 10,000 fossils, with nearly half of them being titanosaurs, including several partial skeletons, mostly articulated or with low dispersion. The study of partially complete and articulated series of cervical, dorsal and caudal vertebrae suggests the presence of three or four different taxa in this site. An almost complete hindlimb from one of the most complete titanosaurian individuals from Lo Hueco (HUE-EC-06) is herein described. This individual also preserves dorsal, sacral and caudal vertebrae, chevrons, pelvis and an osteoderm in association with the caudal vertebrae. This right hindlimb is one of the most complete in the European upper Campanian-lower Maastrichtian, including femur, tibia, fibula and an almost complete pes (metatarsals I to V, non-ungual pedal phalanges I-1, II-1 and III-1, and unguals I-2 and III-2). The femur has a well-developed lateral bulge, a medial accessory trochanter close to the fourth trochanter, and the distal condyles extended to the anterior surface. The femur of HUE-EC-06 differs from Lohuecotitan in presenting a higher eccentricity in the cross-section of the middle of the shaft and a medially inclined linea intermuscularis cranialis. The fibula displays a well developed anteromedial crest, an asymmetrical proximal end and an accessory anterior trochanter, which is shared by Lohuecotitan and Jainosaurus. The metatarsal IV is larger than metatarsal III, a feature only shared by some giant forms of Colossosauria (Epachthosaurus and Notocolossus) and the saltasaurid Alamosaurus. HUE-EC-06 shares the tail morphology with another individual from Lo Hueco (HUE-EC-13, which did not its preserve hindlimbs) and both were recovered as non-lirainosaurines saltasaurids in the phylogenetic analyses performed.

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Más información: 

• Referencia: Mocho, P., Escaso, F., Marcos-Fernández, F., Páramo, A., Vidal, D., Ortega, F. A titanosaurian hindlimb from the late Campanian–early Maastrichtian fossil-site of Lo Hueco (Cuenca, Spain). In Moncunill-Solé, B., Blanco, A., Grandal d’Anglade, A., González Fortes, G., Santos Fidalgo, L., Bao, R. (Eds.), Libro de Resúmenes de las XXXIX Jornadas SEP. Palaeontological Publications 5, 193. 
• Imagen: Pedro Mocho en un momento de su interlocución en una de las sesiones de científicas del congreso.

Elementos apendiculares de terópodos paravianos del yacimiento de Lo Hueco en las XXXIX Jornadas de la SEP

En las pasadas XXXIX Jornadas de la SEP se presentó un estudio sobre el registro de dinosaurios terópodos del Cretácico Superior de Lo Hueco con el trabajo "Appendicular elements of paravian theropods from the Upper Cretaceous fossil site of Lo Hueco (Cuenca, Spain)”. El conjunto de material estudiado incluye elementos de las caderas escapular y pélvica, así como de los miembros anteriores y posteriores. En estos elementos, aunque posiblemente pertenezcan a distintos individuos, se han podido identificar en su mayoría un conjunto de características compatibles con las de dromeosáuridos velocirraptorinos. Además, algunos de los ejemplares presentan semejanzas con los taxones Balaur bondoc y Pneumatoraptor fodori del Maastrichtiense de Rumanía y el Santoniense de Hungría, respectivamente, así como con algunos restos aislados del Cretácico Superior de Francia. El registro fósil de Lo Hueco incluye uno de los conjuntos más amplios y bien preservados de pequeños terópodos dromeosáuridos conocido hasta el momento en el Cretácico Superior de Europa, destacando su importancia para la comprensión de la diversidad y paleobiogeografía de estos dinosaurios. A continuación dejamos el resumen:

The paleontological fossil site of Lo Hueco (Cuenca, Spain) comprises a sequence of mudstone layers belonging to the upper Campanian-lower Maastrichtian levels of the Villalba de la Sierra Formation, which has yielded a rich and diverse record of vertebrate fossils. Theropod dinosaurs are mainly represented by isolated material, mostly attributed to different maniraptoran clades, and few elements identified as belonging to abelisaurids. Here, a collection of appendicular remains of small-sized theropods collected in Lo Hueco is described and their taxonomic affinities are discussed. This collection includes an almost complete right scapulocoracoid, an almost complete right humerus and a fragment of the distal end of a left humerus, a partial left ilium, and an articulated almost complete left metatarsus. These elements show several features typical of paravian coelurosaurs, including: (1) completely fused scapulocoracoid; (2) almost straight proximal margin of the humerus in anterior and posterior views; (3) well-developed and proximally placed deltopectoral crest; (4) deltopectoral crest straight anteriorly, so that it is approximately perpendicular to the long axis of the proximal surface of the humerus in proximal view; (5) pubic peduncle of the ilium much longer anteroposteriorly than the ischiadic peduncle, and wider anteroposteriorly than the dorsoventral depth; (6) shallow supracetabular crest of the ilium; (7) presence of a supratrochanteric process in the dorsolateral margin of the ilium; (8) distal tarsals fused to the metatarsus; and (9) shaft of metatarsal IV mediolaterally widened and flat in cross section. The combination of features on these elements is compatible with that of velociraptorine dromaeosaurids and shows also some similarities (but not identical) with the enigmatic taxa Balaur bondoc and Pneumatoraptor fodori from the lower Maastrichtian of Romania and the Santonian of Hungary respectively, as well as with some isolated specimens from the Upper Cretaceous of southern France.

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Más información:

• Referencia: Malafaia, E., Escaso, F., Coria, R., Ortega, F. Appendicular elements of paravian theropods from the Upper Cretaceous fossil site of Lo Hueco (Cuenca, Spain). In Moncunill-Solé, B., Blanco, A., Grandal d’Anglade, A., González Fortes, G., Santos Fidalgo, L., Bao, R. (Eds.), Libro de Resúmenes de las XXXIX Jornadas SEP. Palaeontological Publications 5, 183.

Tortugas pleurodiras de Israel en las XXXIX Jornadas de la SEP

Una de las tortugas con mejor registro para el Mesozoico de Europa es Algorachelus. Esta forma fue definida en el centro de España, en la localidad de Algora, en Guadalajara. Su presencia ha sido posteriormente documentada en varias localidades ibéricas, tanto en España como en Portugal. Además, actualmente sabemos que este género vivió también en Estados Unidos. Aunque se había propuesto que Algorachelus podría estar presente el Oriente Próximo, hasta ahora esta hipótesis no había sido adecuadamente justificada. El análisis de varios especímenes de tortugas pleurodiras procedentes del registro cenomaniense (base del Cretácico Superior) de Israel ha sido presentado en las recientemente celebradas XXXIX Jornadas de la Sociedad Española de Paleontología, mediante una comunicación oral cuyo título es “New data on the bothremydid turtle from the Cenomanian of the Middle East”. El resumen de este estudio es el siguiente:

The current biogeographic distribution of pleurodiran turtles is restricted to intertropical regions. This is because they require warm climatic conditions. However, the fossil record allows to recognize that the biogeographical distribution of this lineage was much broader in past periods with warm global temperatures. In this sense, these turtles lived in Europe during different geological stages, becoming very abundant and diverse there. The lineage of Pleurodira recognized as the most successful on this continent is Bothremydidae. It is identified as the earliest to disperse from Gondwanan areas to the northern continents. The oldest bothremydid known in Laurasia is Algorachelus. This genus is identified in the Cenomanian record of the Middle East, Europe, and North America. A different species is identified in each of these regions. Although the oldest identified species of Algorachelus was that from Israel, information about it was, until now, extremely limited. It was erected in the 1970s, when the species was erroneously attributed to another lineage of pleurodiran turtles (i.e., Podocnemididae), being originally attributed to the exclusively South American genus Podocnemis. The detailed revision of the classical material of this species (i.e., Algorachelus parva) is carried out here, numerous anatomical details misinterpreted almost 50 years ago being amended. In addition, new, well-preserved specimens are identified and analyzed. As a result, knowledge about this species of great paleobiogeographic relevance is significantly increased.

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Más información:

• Referencia: Pérez-García, A. New data on the bothremydid turtle from the Cenomanian of the Middle East. In Moncunill-Solé, B., Blanco, A., Grandal d’Anglade, A., González Fortes, G., Santos Fidalgo, L., Bao, R. (Eds.), Libro de Resúmenes de las XXXIX Jornadas SEP. Palaeontological Publications 5, 205.

Reconstrucción esquelética 3D y proporción de extremidades cursoriales de Afrovenator abakensis en las XXXIX Jornadas de la SEP

En las XXXIX Jornadas de la Sociedad Española de Paleontología, celebradas la semana pasada en A Coruña, se presentó una ponencia sobre un nuevo espécimen de Afrovenator abakensis, menos completo y de menor tamaño que el holotipo pero con nuevos restos no presentes en él, incluyendo una tibia y pes mucho más completos. Mediante la fotogrametría y la paleontología digital se reconstruyeron la cola, cadera y patas de ambos especímenes y se infirió en cuestiones ontogenéticas y de capacidad cursorial. Los resultados fueron la posible asignación del espécimen nuevo como un adulto de tamaño pequeño, con menor capacidad cursorial que el holotipo, y presentando este una mayor capacidad respecto a otros terópodos con una masa y longitud similares. El resumen es el siguiente:

We present new specimens from the presumed Late Jurassic age megalosauroid Afrovenator abakensis discovered at the locality of Tawachi in the Tiouraren Formation of Niger. New bones include the premaxillae, dentaries and appendicular skeleton. The new premaxillae have a nasal process with a slight less steep angle than previously reconstructed, resulting in a slightly larger external naris. The new dentaries have a more robust symphysis and a more slender midsection, somewhat reminiscent to the symphyseal expansion in the lower jaw of spinosaurids, albeit not as dramatic. Preserved teeth in situ on the dentaries show characters similar to those on the holotype, compatible with a megalosauroid and different from those expected in a ceratosaur like the contemporary Spinostropheus. The absolute length of the hindlimb of the new specimen of Afrovenator is smaller than the holotype, but the tibia/femur ratio is greater than what was estimated previously. The tibia is longer relative to the femur than previously reconstructed and may have had a length close to that of the femur. Along with the nearly completely pes, only the distal phalanges of Digit II and IV are missing, the hindlimb is almost complete. After digitizing the fossils using computed tomographic scans and SfM photogrammetry we obtained allometric and biomechanical calculations. These indicate that Afrovenator has higher cursorial limb proportion scores than Allosaurus fragilis but lower than the abelisaur Aucasaurus garridoi, all of which are theropods of similar size and body mass. While Afrovenator lacks the cursorial adaptations seen in abelisaurids (e.g., extremely dorsalized caudal ribs for a larger caudofemoralis attachment area) it has a slightly taller iliac blade than its relative Torvosaurus suggesting stronger hip protraction and knee extension.

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Más información:

• Referencia: González Pérez, A., Ciudad Real, M., Simarro Cano, A., Vidal, D., Sereno, P. C. Updated 3D skeletal reconstruction and cursorial limb proportion of Afrovenator abakensis (Theropoda: Megalosauridae) with new specimens. In Moncunill-Solé, B., Blanco, A., Grandal d’Anglade, A., González Fortes, G., Santos Fidalgo, L., Bao, R. (Eds.), Libro de Resúmenes de las XXXIX Jornadas SEP. Palaeontological Publications 5, 71.

Cocodrilos notosuquios del Eoceno de Zamora (sí, Zamora) en las XXXIX Jornadas de la SEP

En las pasadas XXXIX Jornadas de la Sociedad Española de Paleontología celebradas en A Coruña, se presentó una comunicación sobre cocodrilos notosuquios del Cenozoico ibérico. Los notosuquios son crocodyliformes muy alejados filogenéticamente de los cocodrilos modernos y su presencia en Europa se documenta a partir de restos muy fragmentarios recolectados en Portugal, España, Francia y Alemania, lo que no ha facilitado la interpretación del grupo en Europa. En esta comunicación se han presentado nuevos restos procedentes de Corrales del Vino (Zamora), muestreados en niveles de la Formación Corrales (Eoceno Medio, Luteciense). Estos restos aportan información anatómica relevante sobre los notosuquios del Eoceno de la Cuenca del Duero (en este caso del sector Zamora) y permite discutir el estatus taxonómico y filogenético de las formas del Duero en el contexto de los notosuquios del resto de Europa, África y América del Sur. El resumen de lo defendido en esta comunicación dice:

Notosuchian crocodyliforms have been known from the Europe Eocene since the 1960s. However, these finds generally corresponded to fragmentary remains collected in Portugal, Spain, France and Germany, so that their phylogenetic position was controversial. New remains from the Corrales del Vino site (Zamora, Spain), collected from levels of the Corrales Formation (Lutetian, Middle Eocene), are presented here. They comprise mainly disarticulated skull parts and isolated but well-preserved axial elements. Most of them are well ossified, so this condition indicates maturity. In addition, much smaller elements are also identified, such as a complete mandibular ramus with teeth, probably from juveniles. These new remains help to clarify some anatomical information that was not present in the previously recorded specimens from Zamora sites, and also complete the available material assigned to the Portuguese notosuchian Iberosuchus from other localities of the same formation (e.g. the El Viso-Madridanos fossil-site, also in the Zamora Province). The new material shows intraspecific variability, at least partially linked, most probably, with ontogenetic changes of this notosuchian species from Zamora. Recently, some new notosuchians species have been described from Spain and France (e.g. Doratodon, Ogresuchus and Dentaneosuchus), showing the biogeographic extension of these taxa in Europe from the Cretaceous to the Eocene, and several phylogenetic relationships between them and their putative Gondwanan relatives have been proposed. This contribution presents some new anatomical details for the notosuchian from the Eocene of Zamora and discusses its taxonomic and phylogenetic status in the context of the European, African and South American forms.

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Más información: 

• Referencia: Ortega, F., de Celis, A., Martín de Jesús, S., Narváez, I., Pérez-García, A., Catalá, J., Arcucci, A. B. New remains of notosuchian crocodyliforms from the Middle Eocene of Zamora (Spain). Taxonomic and phylogenetic status. In Moncunill-Solé, B., Blanco, A., Grandal d’Anglade, A., González Fortes, G., Santos Fidalgo, L., Bao, R. (Eds.), Libro de Resúmenes de las XXXIX Jornadas SEP. Palaeontological Publications 5, 198. 
• Imagen: Francisco Ortega en un momento de su exposición en la sesión de paleontología general del congreso.
• Nota: El nuevo material ha sido recientemente depositado en la Sala de las Tortugas de la Universidad de Salamanca.

Estudio neuroanatómico de Azzabaremys moragjonesi en las XXXIX Jornadas de la SEP

Aunque la mayoría de especies de tortugas pleurodiras extintas y la totalidad de formas actuales de este grupo son formas dulceacuícolas o de medios litorales, algunos miembros de Bothremydidae presentan adaptaciones a ambientes pelágicos, como es el caso de los Nigeremydini. En las XXXIX Jornadas de la Sociedad Española de Paleontología celebradas en A Coruña entre el 2 y el 5 de Octubre se presentó la primera reconstrucción del único cráneo conocido hasta la fecha de Azzabaremys moragjonesi, que corresponde al holotipo de esta especie del Paleoceno de Mali. En este trabajo se evaluaron las modificaciones neuroanatómicas en este taxón respecto al resto de botremídidos de los que se conoce su neuroanatomía, así como las posibles convergencias anatómicas en las cavidades craneales con otras formas de tortugas adaptadas a un modo de vida marino, principalmente con grupos de criptodiras y otras formas de tortugas mesozoicas basales. El resumen del póster se expone a continuación:

Although all extant side-necked turtles are freshwater forms, as was the case with most extinct pleurodires, some extinct podocnemididoid turtles (i.e., several bothremydid species and the Stereogenyini podocnemidids) have been interpreted as possible inhabitants of coastal or even open marine environments. This assumption is based on sedimentary evidence, rather than on anatomical modifications related to a coastal or pelagic way of life. In this context, Nigeremydini has been identified as a putative marine group of Bothremydidae, which inhabited the Trans-Saharian Seaway from the Maastrichtian to the Paleocene. Anatomical and physiological adaptations to pelagic environments in turtles are linked to the changes in salinity and density of this habitat in relation to freshwater environments, as well as the greater capacity for the locomotion in the open sea. Modifications in appendicular and shell osseous elements, but also the presence of well-developed salt glands related to an osmoregulatory function, have been reported from the representatives of Chelonioidea (including extant and extinct members of Cheloniidae and Dermochelyidae), as well as for some extinct groups of Mesozoic and Cenozoic turtles. Modifications of some neuroanatomical elements, as the pattern of the facial nerve system or the semicircular canals of the endosseous labyrinth, are also related with this pelagic lifestyle. The skull of the holotype and unique known specimen of the Malian Paleocene Azzabaremys moragjonesi was scanned through a high-resolution Micro-CT scan to reconstruct the internal cranial cavities and to analyze the neuroanatomical elements of this member of Nigeremydini. These structures will be compared with those known from marine forms of Cryptodira and other extinct lineages (i.e., Protostegidae, Plesiochelyidae, and Sandownidae) to identifying potential adaptive convergences to pelagic environments.

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Más información:

• Referencia: Martín-Jiménez, M., Pérez-García, A. Evaluating the potential development of neuroanatomical modifications for marine environment adaptations in Pleurodira. In Moncunill-Solé, B., Blanco, A., Grandal d’Anglade, A., González Fortes, G., Santos Fidalgo, L., Bao, R. (Eds.), Libro de Resúmenes de las XXXIX Jornadas SEP. Palaeontological Publications 5, 73.

Más información sobre la anatomía de Paludidraco multidentatus en las XXXIX Jornadas de la SEP

Miembros del Grupo de Biología Evolutiva de la UNED han presentado durante las XXXIX Jornadas de la Sociedad Española de Paleontología, el trabajo titulado “New anatomical information about Paludidraco multidentatus and implications for Simosauridae (Nothosauroidea, Sauropterygia)” en formato oral. En este trabajo se ha presentado la anatomía detallada del holotipo del simosáurido español P. multidentatus. En este sentido, se proporciona una diagnosis actualizada tanto del taxón español, así como de su taxón hermano Simosaurus gaillardoti, y del clado Simosauridae. A continuación, os dejamos el resumen perteneciente a este trabajo:

Paludidraco multidentatus is an eosauropterygian reptile from the Carnian (Late Triassic) of Central Spain, defined less than a decade ago. This taxon is the only species of the clade Simosauridae described from Iberian remains. Its holotype represents one of the most complete sauropterygian skeletons in southwestern Europe, preserving both the skull and the relatively complete and articulated postcranial skeleton. One additional specimen of this taxon has been analyzed so far, corresponding to an isolated skull, identified as the paratype. The only other representative of Simosauridae was previously defined as Simosaurus gaillardoti, from the Ladinian (Middle Triassic) of France and Germany. This species is relatively well known since the 19th century based on abundant but generally isolated material. The Spanish taxon is a bizarre sauropterygian, interpreted as a filter feeder, showing adaptations to a slow swimming lifestyle near the seabed of coastal waters. It notably differs from the ecological niche proposed for S. gaillardoti, identified as an active predator with a relatively durophagous diet. Simosauridae is a poorly understood sauropterygian clade compared to other eosauropterygian lineages such as Nothosauria or Plesiosauria. The well-preserved holotype of P. multidentatus was only briefly described in the paper in which it was defined, the postcranial skeleton being poorly characterized. A further and thorough preparation of this specimen was recently performed, so that a detailed description of the postcranial skeleton could be provided. Here, we present some preliminary results and new information about the axial skeleton of P. multidentatus. In addition, several diagnostic characters involving the axial skeleton of Simosauridae are discussed.

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Más información:

• Referencia: Cabezuelo-Hernández, A., de Miguel Chaves, C., Ortega, F., Pérez-García, A. 2024. New anatomical information about Paludidraco multidentatus and implications for Simosauridae (Nothosauroidea, Sauropterygia). In Moncunill-Solé et al. (Eds.), Libro de Resúmenes de las XXXIX Jornadas SEP. Palaeontological publications 5, 155.