New material of Alierasaurus ronchii (Synapsida, Caseidae) from the Permian of Sardinia (Italy), and its phylogenetic affinities

Romano, Marco; Ronchi, Ausonio; Maganuco, Simone; Nicosia, Umberto

doi:10.26879/684

Cited by 15 publications

(20 citation statements)

References 36 publications

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“…; Romano & Nicosia ; Romano et al . ) and likely had a bulky torso for high‐fibre fermentation. The study indicated that the portion of a long bone most affected by allometric growth is the mid‐shaft width of the bone (Romano ).…”

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confidence: 99%

Long bone scaling in Captorhinidae: do limb bones scale according to elastic similarity in sprawling basal amniotes?

Romano

Rubidge

2019

LET

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Captorhinids are a speciose clade of sauropsids that are crucial to understand several aspects of basal amniote general biology. Members of the Captorhinidae explored different diets and, amongst basal amniotes, were one of the first groups to demonstrate high‐fibre herbivory. Several papers have been published on the cranial anatomy of captorhinids, but there are relatively few studies which focus on the post‐cranium, especially on the appendicular skeleton and long bones. This contribution presents the first quantitative long bone scaling in Captorhinidae performed through morphometric analyses. From classical biomechanical research, it is well‐established that to accommodate an increase in size, gravity will result in elastic deformation of long bones. This outcome is especially significant in terrestrial tetrapods with a sprawling limb posture such as captorhinids, where great torsional stresses are applied to long bones, both during locomotion and in the resting phase. In this paper, we test whether the consistent evolutionary size increase in captorhinids led to major re‐patterning in long bone structure as theoretically expected, based on the theory of elastic similarity. Morphometric analysis shows that, apart from a small positive allometry in the humerus, captorhinid long bones scale geometrically as body size increases. Thus, the predicted elastic similarity to maintain similar levels in peak stress with an increase in dimensions does not seem not to apply to long bone evolution in captorhinids. We propose that, as already observed experimentally in larger‐bodied varanid lizards, large captorhinids could also mitigate size‐related increases in stress by reducing femur rotation and increasing the percentage of the stride cycle during which the right hindfoot was on the ground (i.e. the duty factor). In this way, large captorhinids could avoid reaching peak stress thresholds by sacrificing speed during locomotion and without a substantial long bone re‐patterning or postural change.

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confidence: 99%

Long bone scaling in Captorhinidae: do limb bones scale according to elastic similarity in sprawling basal amniotes?

Romano

Rubidge

2019

LET

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“…(Cassinis et al, 2003) in the Torre del Porticciolo locality. The chronostratigraphic position of this rock unit was not well established until the discovery of the caseid Alierasurus ronchii (Romano & Nicosia, 2014;Romano, Ronchi, et al, 2017;Ronchi et al, 2011), which established attribution of the unit to the latest Kungurian-Roadian. interbedded with dark-red finer material (see also Ronchi et al, 2011).…”

Section: The Cala Del Vino Fmmentioning

confidence: 99%

“…In previous work, these fossils were ascribed to the new genus and species Alierasaurus ronchii , referable to the family Caseidae (Romano & Nicosia, ), a long‐lived group of herbivorous “pelycosaurs” primarily known from North America, but with a few European records as well (Brocklehurst, Romano, & Fröbisch, ; Reisz et al, ; Romano, ; Romano, Brocklehurst, & Fröbisch, ; Romano & Nicosia, ; Sigogneau‐Russell & Russell, ). More recently, additional material of Alierasaurus described from the type locality established the phylogenetic position of the Sardinian taxon within the monophyletic Caseidae (Romano, Ronchi, Maganuco, & Nicosia, ); in addition, the analysis of new recovered material has shown how this genus probably represents the largest “pelycosaur” ever found, with an estimated total length of 7 m (see Romano, Ronchi, et al, ).…”

Section: Introductionmentioning

confidence: 96%

“…More recently, additional material of Alierasaurus described from the type locality established the phylogenetic position of the Sardinian taxon within the monophyletic Caseidae (Romano, Ronchi, Maganuco, & Nicosia, 2017); in addition, the analysis of new recovered material has shown how this genus probably represents the largest "pelycosaur" ever found, with an estimated total length of 7 m (see Romano, Ronchi, et al, 2017).…”

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confidence: 99%

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New basal synapsid discovery at the Permian outcrop of Torre del Porticciolo (Alghero, Italy)

Romano

Citton

Maganuco³

et al. 2018

Geological Journal

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The Torre del Porticciolo fossil locality is notable for producing the first osteological material of a basal (i.e., non-mammalian) synapsid in Italy, the giant herbivore Alierasaurus ronchii, which although known from fragmentary remains, likely represents the largest known late early to early middle Permian synapsid (6-7 m total length). Recently, a new productive site was discovered about 100 m from the Alierasaurus type locality, but roughly at the same stratigraphic level. The fragmentary nature of most of the recovered bones prompted a taphonomical analysis in order to define the type of find, the kind of burial, and the mode of preservation. The vertebrate remains allowed us to infer a complex taphonomical process involving a multiphase entombment. The recovered bones were subjected to both re-exhumation and reworking. The last short and violent transportation phase before final entombment occurred as a high-energy flow, probably caused by a river flood that carried sediment and bones together to be emplaced in a semi-perennial pond in a crevasse splay deposit. Preliminary analysis of recovered material indicates the presence of a large carnivorous basal synapsid referable to the family Sphenacodontidae. This discovery represents the first carnivorous non-therapsid synapsid from the Permian of Italy and one of only very few known from Europe.

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“…The find also constitutes the third paleontological site of the Torre del Porticciolo area. From this area, the first palaeontological site (TdP1) yielded the bone remains of a huge caseid synapsid (Ronchi, Sacchi, Nicosia, & Romano, ; Ronchi, Sacchi, Romano, & Nicosia, ) named Alierasaurus ronchii (Romano & Nicosia, , ; Romano, Ronchi, Maganuco, & Nicosia, ). The second one (TdP2), discovered in 2015 and excavated in 2016 and 2017, returned cranial and post‐cranial remains, temporarily ascribed to a meat‐eating synapsid (Romano et al, ).…”

Section: Introductionmentioning

confidence: 99%

First tetrapod footprints from the Permian of Sardinia and their palaeontological and stratigraphical significance

Citton

Ronchi

Maganuco³

et al. 2018

Geological Journal

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The Torre del Porticciolo palaeontological locality (Alghero, north‐west Sardinia, Italy) is important for having provided the skeletal remains of the first Permian basal synapsid from Italy, Alierasaurus ronchii, the largest late early Permian to early middle Permian non‐therapsid synapsid known to date. Recently, other skeletal remains preliminarily attributed to a carnivorous non‐therapsid synapsid were described from a second site, approximately from the same stratigraphic level within the Cala del Vino Fm. During the excavation of this second site, tetrapod tracks were found near Cala Viola, about 1 km from the first two sites. The new find represents the first ichnological record from the Permian of Sardinia. The ichnological analysis allowed the recognition of tetrapods presently not recognized, just on the base of skeletal remains. This new evidence sheds more light on the faunal diversity within the Cala del Vino Fm., which is one of the few examples in the Permian of Europe of a combined ichno‐ and body‐fossil record. The tracks have been referred to as Merifontichnus, an ichnotaxon established from the uppermost portion of the Permian succession of the Lodève Basin in southern France. The new material is the first reliable occurrence of this ichnotaxon from Italy and would represent, to date, the oldest occurrence of the ichnogenus.

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New material of Alierasaurus ronchii (Synapsida, Caseidae) from the Permian of Sardinia (Italy), and its phylogenetic affinities

Cited by 15 publications

References 36 publications

Long bone scaling in Captorhinidae: do limb bones scale according to elastic similarity in sprawling basal amniotes?

Long bone scaling in Captorhinidae: do limb bones scale according to elastic similarity in sprawling basal amniotes?

New basal synapsid discovery at the Permian outcrop of Torre del Porticciolo (Alghero, Italy)

First tetrapod footprints from the Permian of Sardinia and their palaeontological and stratigraphical significance

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