27.4.16

El esqueleto apendicular de los alodaposúquidos de Lo Hueco en el 1st IMERP-XIV EJIP


Durante el 1st IMERP - XIV EJIP, celebrado en Alpuente (Valencia), Ane de Celis presentó nueva información sobre los alodaposúquidos de Lo Hueco en el trabajo "Study of the pelvis and hindlimb of the Allodaposuchidae (Crocodyliformes, Eusuchia) from the Upper Cretaceous of Lo Hueco (Cuenca, Spain)".

En este trabajo se establecen dos morfotipos diferentes de fémur e ilion, consistentes con la presencia de dos especies distintas de alodaposúquidos, constatada a partir del material craneal por Narváez (2015). Por otro lado, su comparación con cocodrilos actuales mediante el uso de morfometría tradicional, mostró que existen diferencias en este material postcraneal (ilion, isquion y fémur). Las diferencias, aunque pequeñas, pueden resultar interesantes a nivel filogenético y/o locomotor. Puede consultarse el resumen a continuación:

The late Campanian-early Maastrichtian site of Lo Hueco (Cuenca, Spain) has provided numerous macrofossils; among them stands out the great number of cranial and postcranial remains attributable to non-crocodylian eusuchians. Cranial remains have been assigned to two new allodaposuchid species. The early acquisition of evolutionary novelties in Eusuchia is an interesting process to understand the rise of the crown-group Crocodylia. Morphological changes that have been described at basal eusuchians imply the modification of postcranial elements and affect mainly locomotion, but the process of acquisition of associated anatomical features to this shift in the pelvic girdle and hindlimb has not yet been studied in detail.

This preliminar study describes pelvic (illium and ischium) and femoral remains of allodaposuchid crocodiles from Lo Hueco. Taking into account the co-existence of two species in the site, and assuming that the postcranial skeleton of crocodiles is not particularly conservative, it is expected to distinguish two pelvic and femoral morphotypes. Besides, it is expected to find morphological differences between allodaposuchid and nowadays existing crocodiles. The methods employed to determine possible morphotypes were based on morphological criteria, while traditional morphometric techniques were used to establish differences between allodaposuchids and extant crocodiles remains. Measurements were taken and subjected to multivariate data analysis (PCA and CA).

Results allow the identification of two iliac and femoral morphotypes in the sample of Lo Hueco, based on differences at the caudal end of the iliac blade and proportions of the posterior tubercle of the proximal femoral end, among others. Morphometric analysis shows that differences between extant crocodiles and allodaposuchids from Lo Hueco do exist. These differences are found primarily at the iliac blade, ischial blade, femoral fourth trochanter and femoral distal end. These results indicate the existence of particular pelvic and femoral morphologies at Lo Hueco allodaposuchids, and also provide new information about the early postcranial changes in the eusuchian lineage.

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Referencias
Imagen
  • En la imagen, Ane de Celis en el comienzo de su presentación, en una fotografía de Pedro Mocho, al que nunca agradeceremos lo suficiente su labor gráfica.