Showing posts with label Diplodocoidea. Show all posts
Showing posts with label Diplodocoidea. Show all posts

Thursday, August 15, 2024

[Paleontology • 2024] Campananeyen fragilissimusThey all floated in the Cretaceous: New rebbachisaurid (Sauropoda: Diplodocoidea) with a highly pneumatized skeleton from the Upper Cretaceous (lower Cenomanian) of Patagonia, Argentina

 

 Campananeyen fragilissimus
 Lerzo, Fernández-Baldor, Canale, Whitlock, Otero & Gallina, 2024


ABSTRACT
Rebbachisaurids are a group of basal diplodocoid sauropods that diversified primarily in Gondwana between the early Lower Cretaceous and the early Upper Cretaceous. Their phylogenetic relationships are still under debate given the fragmentary and incomplete nature of its remains. Here, we provide a detailed description of the postcranial remains of Campananeyen fragilissimus gen. et sp. nov. from the Candeleros Formation (lower Cenomanian) of Neuquén Province, Argentina. Campananeyen presents notable features that allow it to be recognised as a new species by the presence of an underdeveloped crista prootica, paraoccipital process internally hollow and a fuse dorsal alar arm of the ilium. The phylogenetic analysis recovered this taxon as a basal rebbachisaurid closely related to Zapalasaurus, Sidersaura and the specimen from La Amarga Formation MACN-Pv-N 35. The new rebbachisaurid is recovered as the sister taxon of Sidersaura due the presence of procoelous posterior caudal vertebrae and dorsoventrally flattened posterior caudal centra. C. fragilissimus presents an extreme pneumatization of the sacral region with an autapomorphic dorsal alar arm of the sacral transverse processes. Finally, the phylogenetic analysis supports a South American origin for Rebbachisauridae and an early diversification to Africa and Europe by the Barremian-Aptian as previously suggested.

KEYWORDS: Candeleros formation, Dinosauria, Pneumatization, Gondwana, Campananeyen, Rebbachisauridae


Campananeyen fragilissimus gen. et sp. nov. 


 
Lucas N. Lerzo, Fidel Torcida Fernández-Baldor, Juan I. Canale, John A. Whitlock, Alejandro Otero and Pablo A. Gallina. 2024. They all floated in the Cretaceous: New rebbachisaurid (Sauropoda, Diplodocoidea) with a highly pneumatized skeleton from the Upper Cretaceous (lower Cenomanian) of Patagonia, Argentina. Historical Biology: An International Journal of Paleobiology. DOI: doi.org/10.1080/08912963.2024.2383708  


Thursday, January 4, 2024

[Paleontology • 2024] Sidersaura maraeThe Last of the Oldies: A basal rebbachisaurid (Sauropoda: Diplodocoidea) from the early Late Cretaceous (Cenomanian–Turonian) of Patagonia, Argentina


Sidersaura marae
 Lerzo, Gallina, Canale, Otero, Carballido, Apesteguía & Makovicky, 2024

 
ABSTRACT
Rebbachisauridae is mainly recorded during the early Late Cretaceous in Gondwana, and in South America in particular. Sidersaura marae gen. et sp. nov. was found in rocks of the Huincul Formation (upper Cenomanian – Turonian) of Neuquén Province, Argentina. Sidersaura has notable characteristics that allow recognising it as a new species and defining its phylogenetic relationships. First, it has a frontoparietal foramen, as in dicraeosauridae. It bears fourteen caudal vertebrae with neural arches displaced closer to the anterior margin of the centrum and a ventral longitudinal hollow on middle of the centra, both characters previously considered as titanosaurian synapomorphies, and here recognised in these diplodocoid sauropods. Sidersaura shows a peculiar tarsal condition with an unusual calcaneum morphology which resembles that of basal sauropods. The haemal arches have a stellate morphology with two sets of projections comparable to the specimen MMCh-PV 47 from the Candeleros Formation (Cenomanian), previously described as a titanosaurian. The phylogenetic analysis retrieves Sidersaura as a basal Rebbachisauridae more closely related to Zapalasaurus than to Limaysaurinae. The presence of a basal taxon at Cenomanian – Turonian times, so close to the extinction of the group, implies that the evolutionary history of rebbachisauridae was more complex than previously thought.

KEYWORDS: Neoauropoda, Rebbachisauridae, Godwana, Huincul Formation, Sidersaura, Frontoparietal foramen




Sidersaura marae gen. et sp. nov. 





Lucas Nicolás Lerzo, Pablo Ariel Gallina, Juan Ignacio Canale, Alejandro Otero, José Luis Carballido, Sebastián Apesteguía and Peter Juraj Makovicky. 2024. The Last of the Oldies: A basal rebbachisaurid (Sauropoda, Diplodocoidea) from the early Late Cretaceous (Cenomanian–Turonian) of Patagonia, Argentina. Historical Biology: An International Journal of Paleobiology. DOI: 10.1080/08912963.2023.2297914 

Thursday, February 25, 2021

[Paleontology • 2021] Dzharatitanis kingi • First Rebbachisaurid Sauropod Dinosaur from Asia


Dzharatitanis kingi 
Averianov & Sues, 2021


Abstract
Dzharatitanis kingi gen. et sp. nov. is based on an isolated anterior caudal vertebra (USNM 538127) from the Upper Cretaceous (Turonian) Bissekty Formation at Dzharakuduk, Uzbekistan. Phylogenetic analysis places the new taxon within the diplodocoid clade Rebbachisauridae. This is the first rebbachisaurid reported from Asia and one of the youngest rebbachisaurids in the known fossil record. The caudal is characterized by a slightly opisthocoelous centrum, ‘wing-like’ transverse processes with large but shallow PRCDF and POCDF, and the absence of a hyposphenal ridge and of TPRL and TPOL. The neural spine has high SPRL, SPDL, SPOL, and POSL and is pneumatized. The apex of neural spine is transversely expanded and bears triangular lateral processes. The new taxon shares with Demandasaurus and the Wessex rebbachisaurid a high SPDL on the lateral side of the neural spine, separated from SPRL and SPOL. This possibly suggests derivation of Dzharatitanis from European rebbachisaurids. This is the second sauropod group identified in the assemblage of non-avian dinosaurs from the Bissekty Formation, in addition to a previously identified indeterminate titanosaurian.

Fig 1. Dzharatitanis kingi, USNM 538133 (holotype), anterior caudal vertebra
in posterior (A), right lateral (B), and anterior (C) views.
Scale bar = 10 cm.

Systematic paleontology
Sauropoda Marsh, 1878 
Neosauropoda Bonaparte, 1986 
Diplodocoidea Marsh, 1884 
Rebbachisauridae Bonaparte, 1997 

Genus Dzharatitanis gen. nov.
 
Diagnosis: Differs from Limaysaurus and Tataouinea by convex anterior centrum articular surface. Differs from Lavocatisaurus and Limaysaurus by absence of pleurocoel on centrum. Differs from Comahuesaurus by ‘wing-like’ transverse process. Differs from Amazonsaurus by dorsally directed ventral surface of transverse process. Differs from Cathartesaura, Comahuesaurus, Demandasaurus, Itapeusaurus, and Tataouinea by shallow PRCDF. Differs from Cathartesaura, Itapeusaurus, Katepensaurus, and Tataouinea by absence of TPRL. Differs from Comahuesaurus, Demandasaurus, and Nigersaurus by absence of ventral contact between prezygapophyses. Differs from Comahuesaurus, Demandasaurus, Itapeusaurus, Limaysaurus, Nigersaurus, and Tataouinea by absence of ventral contact between postzygapophyses. Differs from Demandasaurus and Tataouinea by absence of hyposphenal ridge. Differs from Amazonsaurus, Cathartesaura, Katepensaurus, Limaysaurus, Nigersaurus, and Tataouinea by absence of SPRL and SPOL contact. Differs from Amazonsaurus, Cathartesaura, Katepensaurus, Limaysaurus, Nigersaurus, Tataouinea, and Rebbachisaurus by large SPDL on lateral side of neural spine separate from SPRL and SPOL. Differs from Amazonsaurus, Cathartesaura, Comahuesaurus, Itapeusaurus, Lavocatisaurus, and Limaysaurus by presence of lateral process of neural spine. Differs from Rebbachisaurus by proximodistally shorter and anteroposteriorly wider neural spine, which is convex anteriorly in lateral view, and by much wider PRSL.
 
Occurrence: Central Asia; Late Cretaceous (Turonian).

Etymology: From the Dzharakuduk locality in Uzbekistan and Greek τιτάν (titan), a pre-Olympian god in ancient Greek mythology. The generic name is in the feminine gender.


Dzharatitanis kingi sp. nov. 
 2015 Titanosauria indet.: figure 7 in [2].

Holotype: USNM 538127, nearly complete anterior caudal vertebra. Found by David J. Ward and Hans-Dieter Sues during the URBAC (Uzbekistan/Russian/British/American/Canadian) joint paleontological expedition working in Uzbekistan in 1997.

Type locality and horizon: Dzharakuduk, 32 km SW of Mynbulak, Navoi Viloyat, Uzbekistan. The Bissekty Formation, exposed along the Dzharakuduk escarpment, extends from approximately 42°06’22.60’’ N and 62°37’09.00’’ E to 42°05’44.22’’ N and 62°41’06.49’’ E. Age: Late Cretaceous (Turonian). For additional geological details see Redman and Leighton [5].

Etymology: In memory of our colleague and friend Dr. Christopher King (1943–2015) who did much work on the geology of Cretaceous strata in Central Asia.

Remarks: USNM 538127 is likely the first caudal vertebra because of its slightly opisthocoelous centrum and the absence of chevron facets. First caudals with opisthocoelous centra are known for several rebbachisaurids (see Comparison).

 
Alexander Averianov and Hans-Dieter Sues. 2021. First Rebbachisaurid Sauropod Dinosaur from Asia.   PLoS ONE. 16(2): e0246620. DOI: 10.1371/journal.pone.0246620

New diplodocus-like dinosaur from Uzbekistan as the first rebbachisaurid found in Asia.
 

Tuesday, February 5, 2019

[Paleontology • 2019] Bajadasaurus pronuspinax • A New Long-spined Dinosaur from Patagonia sheds light on Sauropod Defense System


Bajadasaurus pronuspinax
Gallina, Apesteguía, Canale & Haluza, 2019

DOI: 10.1038/s41598-018-37943-3
Illustration: Jorge A. González

Abstract
Dicraeosaurids are a group of sauropod dinosaurs characterized by a distinctive vertebral column with paired, long, neural spines, present in an extreme fashion in the South American form Amargasaurus cazaui. This distinctive morphology has been interpreted as a support structure for a thermoregulatory sail, a padded crest for display, a dorsal hump acting as fat reservoir, and even as inner cores for dorsal horns. Other inferred functions (if any) of this structure were related to sexual display and/or defense strategies. Here we describe a new dicraeosaurid sauropod, Bajadasaurus pronuspinax gen. et sp. nov., from Patagonia which preserves the most complete skull of the group and has extremely elongate bifid cervical neural spines that point permanently forward, irrespective of the neck position. Although much shorter versions of this neural spine configuration were already recorded for other dicraeosaurid taxa, the long, anteriorly bent spines of this new dinosaur support the hypothesis that these elongate spines of dicraeosaurid sauropods served as passive defense structures.




Figure 1 Skeletal reconstruction of Bajadasaurus pronuspinax gen. et sp. nov. (MMCh-PV 75), location and quarry map. 
(A) The neck and skull reconstruction in left lateral view, showing preserved bones in white. The complete anterior cervical vertebra is located tentatively in the fifth position (see Description). The total count of cervical elements, as well as the relative extension of the neural spines, is based in the complete series of the related taxon Amargasaurus, the other dicraeosaurid with extremely elongated bifid neural spines along the neck.
 (B) A map of the surrounding area of the Ezequiel Ramos Mexía lake (Neuquén Province, Argentina) showing the type locality of Bajadasaurus (Bajada Colorada) indicated by a white star. 

(C) A quarry map showing the association and location of the remains in the field. at, atlas; ax, axis; cv, cervical vertebra; d, dentary; f, frontal; m, maxilla; po, postorbital; pt, pterygoid; qj, quadratojugal.


Illustration: Jorge A. González

Systematic palaeontology
SAUROPODA Marsh 1878
DIPLODOCOIDEA Marsh 1884
FLAGELLICAUDATA Harris & Dodson 2004

DICRAEOSAURIDAE Huene 1927

Bajadasaurus pronuspinax gen. et sp. nov.

Etymology: Generic name from Bajada (Spanish for downhill, in reference to the locality Bajada Colorada) and saurus (Greek, lizard). Specific epithet from pronus (Latin, bent over forward) and spinax (Greek, spine), referring to the anteriorly pointed, curved, neural spines of the cervical vertebrae.


    



Pablo A. Gallina, Sebastián Apesteguía, Juan I. Canale and Alejandro Haluza. 2019. A New Long-spined Dinosaur from Patagonia sheds light on Sauropod Defense System. Scientific Reports. 9: 1392. DOI: 10.1038/s41598-018-37943-3

  

    

Sunday, December 16, 2012

[Paleontology • 2012] Kaatedocus siberi • The skull and neck of a new flagellicaudatan sauropod from the Morrison Formation and its implication for the evolution and ontogeny of diplodocid dinosaurs



Life reconstruction of the skull of Kaatedocus siberi.
Note the lateral spur on the lacrimal and the palpebral element covering the orbit.
Illustration by Davide Bonadonna (Milan) | davidebonadonna.it

Abstract 
A new taxon of diplodocid sauropod, Kaatedocus siberi gen. et sp. nov., is recognized based on well-preserved cervical vertebrae and skull from the Morrison Formation (Kimmeridgian, Late Jurassic) of northern Wyoming, USA. A phylogenetic analysis places it inside Diplodocinae (Sauropoda: Flagellicaudata: Diplodocidae), as a sister taxon to a clade uniting Tornieria africana and the classical diplodocines Barosaurus lentus and Diplodocus. The taxon is diagnosed by a unique combination of plesiomorphic and derived traits, as well as the following unambiguous autapomorphies within Diplodocidae: frontals separated anteriorly by a U-shaped notch; squamosals restricted to the post-orbital region; presence of a postparietal foramen; a narrow, sharp and distinct sagittal nuchal crest; the paired basal tuber with a straight anterior edge in ventral view; anterior end of the prezygapophyses of mid- and posterior cervical vertebrae is often an anterior extension of the pre-epipophysis, which projects considerably anterior to the articular facet; anterodorsal corner of the lateral side of the posterior cervical vertebrae marked by a rugose tuberosity; posterior margin of the prezygapophyseal articular facet of posterior cervical vertebrae bordered posteriorly by conspicuous transverse sulcus; posterior cervical neural spines parallel to converging. The inclusion of K. siberi and several newly described characters into a previously published phylogenetic analysis recovers the new taxon as basal diplodocine, which concurs well with the low stratigraphical position of the holotype specimen. Dinheirosaurus and Supersaurus now represent the sister clade to Apatosaurus and Diplodocinae and therefore the most basal diplodocid genera. The geographical location in the less known northern parts of the Morrison Fm., where K. siberi was found, corroborates previous hypotheses on faunal provinces within the formation. The probable subadult ontogenetic stage of the holotype specimen allows analysis of ontogenetic changes and their influence on diplodocid phylogeny.

Keywords: Kaatedocus siberi , new genus, Morrison Formation, Howe Quarry


Etymology.Kaate’ means small in the Crow (Absaroka) language, one of the Native American tribes of northern Wyoming. ‘Docus’ is an allusion to Diplodocus and the Greek dokos/δoκoς ‘beam’. ‘Siberi’ is after Hans-Jakob ‘Kirby’ Siber, b. 1942, doctor honoris causa of the University of Zurich, Switzerland. Siber is the founder and director of the Sauriermuseum Aathal, Switzerland, and organized and funded the excavation, preparation and curation of the holotype specimen of Kaatedocus siberi.




Hans-Jakob ‘Kirby’ Siber, b. 1942, doctor honoris causa of the University of Zurich, Switzerland. Siber is the founder and director of the Sauriermuseum Aathal, Switzerland, and organized and funded the excavation, preparation and curation of the holotype specimen of Kaatedocus siberi.





Tschopp, E.; Mateus, O. V. 2012. The skull and neck of a new flagellicaudatan sauropod from the Morrison Formation and its implication for the evolution and ontogeny of diplodocid dinosaurs. Journal of Systematic Palaeontology: 1. DOI:10.1080/14772019.2012.746589

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