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June 2022
45-1
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Print ISSN: 0031-0247
Online ISSN: 2274-0333
Frequency: biannual

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A New caseid Synapsid from the Permian (Guadalupian) of the Lodève basin (Occitanie, France)
 
Ralf Werneburg, Frederik . Spindler, Jocelyn . Falconnet, Jean-Sebastien Steyer, Monique Vianey-Liaud and Jörg-W. Schneider
Keywords: ; Caseidae; France; Guadalupian; semi-aquatic lifestyle

doi: 10.18563/pv.45.2.e2
 
  Abstract

    Lalieudorhynchus gandi gen. nov. and sp. nov. is a new caseid synapsid from the Permian of the Lodève Basin, Occitanie, France. This new taxon is represented by a partial but well-preserved postcranial skeleton, and is characterized by the following apomorphies: a transverse section of the sacral and anterior caudal neural spines with a very thin keel-like process anteriorly, a slender dorsal tip of the dorsal and caudal spines, a narrow distal end of the first sacral rib, a fossa on triceps process of metacoracoid, and a very large distal tarsal 1 of same width than the astragalus, with nearly all sides being shallowly concave.
    The skeleton corresponds to a sub-adult individual that was excavated from the La Lieude Formation dated as Roadian-Capitanian (Guadalupian). A sedimentological and taphonomical analysis of the type locality, together with preliminary osteohistological observations, suggest that this new French caseid was rather aquatic, as already hypothesised for other large forms.
    A phylogenetic analysis of caseids is performed to test the position of this new taxon and to better understand the evolution of the clade: interestingly, Lalieudorhynchus gandi gen. nov. et sp. nov. is closer to the NorthAmerican “Cotylorhynchushancocki than to the other French caseids Ruthenosaurus and Euromycter from the Artinskian of the geographically closer Rodez Basin. These two last caseids document the Artinskian radiation of the clade, which remained diverse until Olson’s extinction. Caseids survived, as Lalieudorhynchus is one of the youngest representatives of the clade, and may have used novel ecological strategies to access their vegetarian food sources.

      


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Small sauropod tracks in the Hettangian of Southern France – A case of ichnite fossilization in an intertidal zone
Pierre Demathieu, Alain Izart, André Charrière and Monique Vianey-Liaud
Keywords: Intertidal zone; Lower Jurassic; Sauropods; Southern France; Tracks

doi: 10.18563/pv.45.2.e1
 
  Abstract

    This paper presents the description and the interpretation of recently discovered traces on a Lower Hettangian dolomitic outcrop in the Bédarieux area, Southern France. One trace set immediately attracted the attention by its resemblance to a small sauropod pes-manus couple but no trackway was visible. As the other traces have a variety of shapes with no obvious significance, it took a thorough examination of the 3D and sedimentological data to come to the conclusion that most traces likely were sauropod tracks made under diverse conditions. Sedimentological and ichnological data indicate that the tracks have been made in the intertidal zone of a carbonated tidal flat shortly before an emersion period. It appears that that the variety of trace shapes is due to a variety of water depths: the sauropods were punting when the water level was high. The lack of trackways seems due to the combination of an underprint situation, buoyancy effects and the small size of the track-bearing slab. Several hypotheses can be considered for explaining the very small size of the tracks, such as insular dwarfism or the immaturity of the trackmakers. 


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