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New Information on Tataouinea hannibalis from the Early Cretaceous of Tunisia and Implications for the Tempo and Mode of Rebbachisaurid Sauropod Evolution.

Fanti F, Cau A, Cantelli L, Hassine M, Auditore M - PLoS ONE (2015)

Bottom Line: We present detailed analyses on the sedimentology and facies distribution at the main quarry and a revision of the vertebrate fauna associated with the skeleton.Results presented here suggest an exclusively South American Limaysaurinae and a more widely distributed Rebbachisaurinae lineage, the latter including the South American taxon Katepensaurus and a clade including African and European taxa, with Tataouinea as sister taxon of Rebbachisaurus.This scenario would indicate that South America was not affected by the end-Jurassic extinction of diplodocoids, and was most likely the centre of the rapid radiation of rebbachisaurids to Africa and Europe between 135 and 130 Ma.

View Article: PubMed Central - PubMed

Affiliation: Dipartimento di Scienze Biologiche, Geologiche e Ambientali, Alma Mater Studiorum, Università di Bologna, Bologna, Italy; Museo Geologico Giovanni Capellini, Alma Mater Studiorum, Università di Bologna, Bologna, Italy.

ABSTRACT
The rebbachisaurid sauropod Tataouinea hannibalis represents the first articulated dinosaur skeleton from Tunisia and one of the best preserved in northern Africa. The type specimen was collected from the lower Albian, fluvio-estuarine deposits of the Ain el Guettar Formation (southern Tunisia). We present detailed analyses on the sedimentology and facies distribution at the main quarry and a revision of the vertebrate fauna associated with the skeleton. Data provide information on a complex ecosystem dominated by crocodilian and other brackish water taxa. Taphonomic interpretations indicate a multi-event, pre-burial history with a combination of rapid segregation in high sediment supply conditions and partial subaerial exposure of the carcass. After the collection in 2011 of the articulated sacrum and proximalmost caudal vertebrae, all showing a complex pattern of pneumatization, newly discovered material of the type specimen allows a detailed osteological description of Tataouinea. The sacrum, the complete and articulated caudal vertebrae 1-17, both ilia and ischia display asymmetrical pneumatization, with the left side of vertebrae and the left ischium showing a more extensive invasion by pneumatic features than their right counterparts. A pneumatic hiatus is present in caudal centra 7 to 13, whereas caudal centra 14-16 are pneumatised by shallow fossae. Bayesian inference analyses integrating morphological, stratigraphic and paleogeographic data support a flagellicaudatan-rebbachisaurid divergence at about 163 Ma and a South American ancestral range for rebbachisaurids. Results presented here suggest an exclusively South American Limaysaurinae and a more widely distributed Rebbachisaurinae lineage, the latter including the South American taxon Katepensaurus and a clade including African and European taxa, with Tataouinea as sister taxon of Rebbachisaurus. This scenario would indicate that South America was not affected by the end-Jurassic extinction of diplodocoids, and was most likely the centre of the rapid radiation of rebbachisaurids to Africa and Europe between 135 and 130 Ma.

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Pelvic elements of Tataouinea hannibalis.Left ilium in lateral view (A). Left pubic peduncle in distal/ventral view (B). Right preacetabular process of ilium in lateral view (C). Right ischium in medial (D) and lateral (E) views. Left ischium in lateral (F) and medial (G) views. Right ischium in proximal (acetabular) view (H). Left ischium in proximal (acetabular) view (I). Scale bar: 10 cm. Abbreviations: am, acetabular margin; col, collapsed area; ic, internal chamber; ilf, iliac facet; pf, pneumatic foramen; prp, preacetabular process; pup, pubic peduncle; se, septa.
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pone.0123475.g019: Pelvic elements of Tataouinea hannibalis.Left ilium in lateral view (A). Left pubic peduncle in distal/ventral view (B). Right preacetabular process of ilium in lateral view (C). Right ischium in medial (D) and lateral (E) views. Left ischium in lateral (F) and medial (G) views. Right ischium in proximal (acetabular) view (H). Left ischium in proximal (acetabular) view (I). Scale bar: 10 cm. Abbreviations: am, acetabular margin; col, collapsed area; ic, internal chamber; ilf, iliac facet; pf, pneumatic foramen; prp, preacetabular process; pup, pubic peduncle; se, septa.

Mentions: Both iliac blades are partially preserved (ONM DT 3, 4; Fig 19A–19C). The dorsal margin of the bones, the postacetabular processes and most of the ischial peduncles are lost. The preacetabular processes are craniocaudally elongate, and flared laterally. In lateroventral view, the cranioventral corner of the preacetabular blade is gently acuminate, with a rounded craniodorsal margin and a slightly concave ventrolateral margin. The cranioventral corner of the lateral surface is rugose and scarred by an irregular series of low bumps. Most of the lateral surface of the blade is uniformly flat, showing a moderate longitudinal convexity toward the ventral margin, where the lateral surface shifts into the ventral surface. The preacetabular blade is internally hollow. A channel is exposed in the broken region craniodorsal to the pubic peduncle. It leads to an internal chamber on the iliac blade. The large size of the exposed channel and the extensive cavitation of the preacetabular blade suggest a pneumatic origin of the feature. It is unclear whether this channel opened externally through a foramen at the level of the damaged area. The pubic peduncle is massive, projected laterally relative to the ventrolateral surface of the preacetabular process, and describing with the latter a wide concavity. In ventral view, the pubic peduncle is “D”-shaped, with the straight caudal margin oriented mediolaterally and the cranial margin broadly rounded. The ventral end of the pubic peduncle is badly eroded, showing the internal pneumatisation composed of large chambers separated by dorsoventrally narrow septa oriented horizontally.


New Information on Tataouinea hannibalis from the Early Cretaceous of Tunisia and Implications for the Tempo and Mode of Rebbachisaurid Sauropod Evolution.

Fanti F, Cau A, Cantelli L, Hassine M, Auditore M - PLoS ONE (2015)

Pelvic elements of Tataouinea hannibalis.Left ilium in lateral view (A). Left pubic peduncle in distal/ventral view (B). Right preacetabular process of ilium in lateral view (C). Right ischium in medial (D) and lateral (E) views. Left ischium in lateral (F) and medial (G) views. Right ischium in proximal (acetabular) view (H). Left ischium in proximal (acetabular) view (I). Scale bar: 10 cm. Abbreviations: am, acetabular margin; col, collapsed area; ic, internal chamber; ilf, iliac facet; pf, pneumatic foramen; prp, preacetabular process; pup, pubic peduncle; se, septa.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4414570&req=5

pone.0123475.g019: Pelvic elements of Tataouinea hannibalis.Left ilium in lateral view (A). Left pubic peduncle in distal/ventral view (B). Right preacetabular process of ilium in lateral view (C). Right ischium in medial (D) and lateral (E) views. Left ischium in lateral (F) and medial (G) views. Right ischium in proximal (acetabular) view (H). Left ischium in proximal (acetabular) view (I). Scale bar: 10 cm. Abbreviations: am, acetabular margin; col, collapsed area; ic, internal chamber; ilf, iliac facet; pf, pneumatic foramen; prp, preacetabular process; pup, pubic peduncle; se, septa.
Mentions: Both iliac blades are partially preserved (ONM DT 3, 4; Fig 19A–19C). The dorsal margin of the bones, the postacetabular processes and most of the ischial peduncles are lost. The preacetabular processes are craniocaudally elongate, and flared laterally. In lateroventral view, the cranioventral corner of the preacetabular blade is gently acuminate, with a rounded craniodorsal margin and a slightly concave ventrolateral margin. The cranioventral corner of the lateral surface is rugose and scarred by an irregular series of low bumps. Most of the lateral surface of the blade is uniformly flat, showing a moderate longitudinal convexity toward the ventral margin, where the lateral surface shifts into the ventral surface. The preacetabular blade is internally hollow. A channel is exposed in the broken region craniodorsal to the pubic peduncle. It leads to an internal chamber on the iliac blade. The large size of the exposed channel and the extensive cavitation of the preacetabular blade suggest a pneumatic origin of the feature. It is unclear whether this channel opened externally through a foramen at the level of the damaged area. The pubic peduncle is massive, projected laterally relative to the ventrolateral surface of the preacetabular process, and describing with the latter a wide concavity. In ventral view, the pubic peduncle is “D”-shaped, with the straight caudal margin oriented mediolaterally and the cranial margin broadly rounded. The ventral end of the pubic peduncle is badly eroded, showing the internal pneumatisation composed of large chambers separated by dorsoventrally narrow septa oriented horizontally.

Bottom Line: We present detailed analyses on the sedimentology and facies distribution at the main quarry and a revision of the vertebrate fauna associated with the skeleton.Results presented here suggest an exclusively South American Limaysaurinae and a more widely distributed Rebbachisaurinae lineage, the latter including the South American taxon Katepensaurus and a clade including African and European taxa, with Tataouinea as sister taxon of Rebbachisaurus.This scenario would indicate that South America was not affected by the end-Jurassic extinction of diplodocoids, and was most likely the centre of the rapid radiation of rebbachisaurids to Africa and Europe between 135 and 130 Ma.

View Article: PubMed Central - PubMed

Affiliation: Dipartimento di Scienze Biologiche, Geologiche e Ambientali, Alma Mater Studiorum, Università di Bologna, Bologna, Italy; Museo Geologico Giovanni Capellini, Alma Mater Studiorum, Università di Bologna, Bologna, Italy.

ABSTRACT
The rebbachisaurid sauropod Tataouinea hannibalis represents the first articulated dinosaur skeleton from Tunisia and one of the best preserved in northern Africa. The type specimen was collected from the lower Albian, fluvio-estuarine deposits of the Ain el Guettar Formation (southern Tunisia). We present detailed analyses on the sedimentology and facies distribution at the main quarry and a revision of the vertebrate fauna associated with the skeleton. Data provide information on a complex ecosystem dominated by crocodilian and other brackish water taxa. Taphonomic interpretations indicate a multi-event, pre-burial history with a combination of rapid segregation in high sediment supply conditions and partial subaerial exposure of the carcass. After the collection in 2011 of the articulated sacrum and proximalmost caudal vertebrae, all showing a complex pattern of pneumatization, newly discovered material of the type specimen allows a detailed osteological description of Tataouinea. The sacrum, the complete and articulated caudal vertebrae 1-17, both ilia and ischia display asymmetrical pneumatization, with the left side of vertebrae and the left ischium showing a more extensive invasion by pneumatic features than their right counterparts. A pneumatic hiatus is present in caudal centra 7 to 13, whereas caudal centra 14-16 are pneumatised by shallow fossae. Bayesian inference analyses integrating morphological, stratigraphic and paleogeographic data support a flagellicaudatan-rebbachisaurid divergence at about 163 Ma and a South American ancestral range for rebbachisaurids. Results presented here suggest an exclusively South American Limaysaurinae and a more widely distributed Rebbachisaurinae lineage, the latter including the South American taxon Katepensaurus and a clade including African and European taxa, with Tataouinea as sister taxon of Rebbachisaurus. This scenario would indicate that South America was not affected by the end-Jurassic extinction of diplodocoids, and was most likely the centre of the rapid radiation of rebbachisaurids to Africa and Europe between 135 and 130 Ma.

Show MeSH
Related in: MedlinePlus