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New titanosauriform (Sauropoda) from the Poison Strip Member of Cedar Mountain Formation (Lower Cretaceous), Utah
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... The centrum of this vertebra is dorsoventrally taller than anteroposteriorly long, with a slightly concave anterior articular surface; the posterior articular surface is poorly preserved. Considering that the anterior articular surface does not have a deep concavity typical of vertebrae classified as procoelous, and that the middle caudal vertebrae of the same specimen are amphicoelous (MCF-PVPH 917/2 and MCF-PVPH 917/3; Fig. 2E-N), it is likely that the posterior face of MCF-PVPH 917/1 was slightly convex or flat, as in the procoelous-opisthoplatyan (see [40]) anterior vertebrae of Malarguesaurus [30]. In contrast, derived titanosaurians have procoelous anterior caudal vertebrae (e.g., Aelosaurini, Saltasaurinae, and Rinconsauria). ...
... The transverse processes are reduced to a low protuberance (Fig. 2F). As in Titanosauriformes, the neural arch of the middle caudal vertebra is placed in the anterior half of the dorsal surface of the centrum (e.g., Giraffatitan, Venenosaurus, Tastavinsaurus, and Dreadnoughtus; [59]; [40]; [60]; [61]). The height of the pedicels (below the level of prezygapophyses) is greater than that of other titanosauriforms (e.g., Lusotitan, Venenosaurus, and Cedarosaurus; [57]; [40]; [62]) but slightly less than the height observed in Malarguesaurus ( [30]: Fig. 6). ...
... As in Titanosauriformes, the neural arch of the middle caudal vertebra is placed in the anterior half of the dorsal surface of the centrum (e.g., Giraffatitan, Venenosaurus, Tastavinsaurus, and Dreadnoughtus; [59]; [40]; [60]; [61]). The height of the pedicels (below the level of prezygapophyses) is greater than that of other titanosauriforms (e.g., Lusotitan, Venenosaurus, and Cedarosaurus; [57]; [40]; [62]) but slightly less than the height observed in Malarguesaurus ( [30]: Fig. 6). The neural spine is transversely thicker and rectangular in lateral view, being 1.5 times as long as high (Fig. 2F, I). ...
The Portezuelo Formation preserves an outstanding record of the upper Turonian – lower Coniacian. Despite the discovery of a significant quantity of sauropod fossil material from the formation, only two species have been formally described to date: Malarguesaurus florenciae and Futalognkosaurus dukei. Here we present new sauropod material mostly composed of non-articulated caudal vertebrae (MCF-PVPH 916 and 917) that belong to two titanosauriforms on the basis of the following features: anterior caudal vertebrae with procoelous-opisthoplatyan articulations, transverse processes that reach the posterior articular face of the centrum and neural spines with a transverse width of around 50% of their anteroposterior length; anterior and middle caudal vertebrae with the neural arch restricted to the anterior half of the centrum; middle caudal centra with circular cross-section. Phylogenetic analysis recovers the new material in close relation to Malarguesaurus within a monophyletic clade at the base of Somphospondyli. This clade shares large pedicel height with a vertical anterior border on the middle caudal vertebrae, a vertical orientation of the neural spines on the distalmost middle caudal vertebrae and proximalmost posterior caudal vertebrae, and subequal relative lengths of the proximal ulnar condylar processes. The specimens presented here are distinct not only from Futalognkosaurus, but also from other indeterminate titanosaurian remains from the same formation. However, there are no significant differences between the specimen MCF-PVPH 917 and Malarguesaurus, but there are differences between the posterior caudal vertebrae of MCF-PVPH 916 and Malarguesaurus, so they could be considered different species. Whilst we err on the side of caution in not naming new taxa here, the two specimens significantly expand what we know about sauropods in the Turonian–Coniacian ecosystems of Patagonia, which will continue to do so as more material is discovered.
Supplementary Information
The online version contains supplementary material available at 10.1186/s12862-024-02280-9.
... The centrum of this vertebra is dorsoventrally taller than anteroposteriorly long, and has a slightly concave anterior surface whereas the posterior one is poorly preserved. Considering that the middle caudal vertebra of the same specimen is amphicoelous (MCF-PVPH 917/2; Fig. 2D-F), it is likely that the posterior face is slightly convex or at, as to the procoelous-opistoplatyan (see [35]) anterior vertebrae of Malarguesaurus [26]. In contrast, derived titanosaurs have procoelous caudal vertebrae (Aelosaurini, Saltasaurinae and Rinconsauria taxa). ...
... Fig. 2E). As in Titanosauriformes, the neural arch of the middle caudal vertebra is placed in the anterior half of the dorsal surface of the centrum (e.g., Giraffatitan, Venenosaurus, Tastavinsaurus, Dreadnoughtus;[51];[35]:Fig. 11.4;[52]: Fig. 8; [53]). ...
The Portezuelo Formation preserves an outstanding record of the upper Turonian - lower Coniacian of Gondwana. Despite the discovery of a significant amount of sauropod fossil material from the Formation, only two species have been formally described to date: Malarguesaurus florenciae and Futalognkosaurus dukei . Here we present new sauropod material mostly composed of non-articulated caudal vertebrae that belong to at least two different titanosauriforms on the basis of following features: anterior caudal vertebrae with procoelous-opistoplatyan articulations, transverse processes that reach the posterior articular face of the centrum and neural spines with a lateromedial width of ~ 50% of its anteroposterior length; anterior and middle caudal vertebra with the neural arch restricted to the anterior half of the centrum; middle caudal centrum with circular cross-section. Phylogenetic analysis recovers the new material in close relation to Malarguesaurus within a monophyletic clade sister to Somphospondily. This clade shares large pedicel height with a vertical anterior border on the middle caudal vertebrae, a vertical orientation of the neural spines on the distalmost middle caudal vertebrae and proximalmost posterior caudal vertebrae, and subequal relative lengths of the proximal ulnar condylar processes. The specimens presented here are distinct not only from Malarguesaurus and Futalognkosaurus , but also from other indeterminate titanosaur remains from the same formation. Whilst we err on the side of caution in not naming new taxa here, the two specimens significantly expand what we know about sauropods in the Turonian-Coniacian ecosystems of Patagonia, which will continue to do so as more material is discovered.
... In lateral view, the proximal articular surface is slightly convex (Figure 15E), as in Limaysaurus and Sauroposeidon (Calvo and Salgado 1995;Rose 2007), unlike the condition present in several Titanosauriformes where this surface is strongly posteriorly inclined (e.g. Antarctosaurus, Epachthosaurus, Gobititan, Venenosaurus, and Notocolossus;von Huene 1929;Tidwell et al. 2001;You et al. 2003;Martínez et al. 2004;González Riga et al. 2016). ...
... On the other hand, in Agustinia, the anterior and posterior surfaces of metatarsal I are straight and sub-parallel in lateral view, at least up to half of the bone, a unique condition within Sauropoda ( Figure 4S). In Tazoudasaurus the anterior and posterior surfaces are straight in lateral view but only in the proximal third of the metatarsal I ( Figure 4U), whereas in Venenosaurus only the anterior edge is straight in lateral view up to half of the bone (Fig. 4AC) (Tidwell et al. 2001;Allain et al. 2004;Allain and Aquesbi 2008;Peyer and Allain 2010). Conversely, the metatarsal I of the rebbachisaurid Lavocatisaurus MAU-PV-1232/81 ( Figure 4A) shows a laminar and prominent posterior surface that strongly resembles the condition seen in Agustinia, although the anterior surface is shallow and concave in lateral view. ...
The Lohan Cura Formation (Albian) at the Cerro de los Leones locality (Neuquén Province, Patagonia, Argentina) yielded several fossil materials, especially sauropod specimens. Among these, Agustinia ligabuei includes postcranial elements of a single individual, with widely debated taxonomy and phylogeny. Here, we provide an extended osteological description and illustrations of the axial and appendicular elements of Agustinia, as well as a revised diagnosis. Moreover, the phylogenetic analysis including a new combination of morphological features recognises Agustinia as a basal Rebbachisauridae, closely related with other South American rebbachisaurids. Our results suggest a more diversified sauropod fauna in the Neuquén Basin, where different members of both neosauropod lineages (i.e. Macronaria and Diplodocoidea) survived in the same region during the Albian age. The reassessment of Agustinia as a basal rebbachisaurid improves our knowledge about the early stages of evolutionary history of Rebbachisauridae, adding new information on the morphological and taxonomic diversification of the clade during the Early Cretaceous of southwestern Gondwana.
... (Continued.)Tidwell et al.[299]; D'Emic et al.[246] royalsocietypublishing.org/journal/rsos R. Soc. Open Sci. ...
Titanosaurian sauropod dinosaurs were diverse and abundant throughout the Cretaceous, with a global distribution. However, few titanosaurian taxa are represented by multiple skeletons, let alone skulls. Diamantinasaurus matildae, from the lower Upper Cretaceous Winton Formation of Queensland, Australia, was heretofore represented by three specimens, including one that preserves a braincase and several other cranial elements. Herein, we describe a fourth specimen of Diamantinasaurus matildae that preserves a more complete skull—including numerous cranial elements not previously known for this taxon—as well as a partial postcranial skeleton. The skull of Diamantinasaurus matildae shows many similarities to that of the coeval Sarmientosaurus musacchioi from Argentina (e.g. quadratojugal with posterior tongue-like process; braincase with more than one ossified exit for cranial nerve V; compressed-cone–chisel-like teeth), providing further support for the inclusion of both taxa within the clade Diamantinasauria. The replacement teeth within the premaxilla of the new specimen are morphologically congruent with teeth previously attributed to Diamantinasaurus matildae, and Diamantinasauria more broadly, corroborating those referrals. Plesiomorphic characters of the new specimen include a sacrum comprising five vertebrae (also newly demonstrated in the holotype of Diamantinasaurus matildae), rather than the six or more that typify other titanosaurs. However, we demonstrate that there have been a number of independent acquisitions of a six-vertebrae sacrum among Somphospondyli and/or that there have been numerous reversals to a five-vertebrae sacrum, suggesting that sacral count is relatively plastic. Other newly identified plesiomorphic features include: the overall skull shape, which is more similar to brachiosaurids than ‘derived' titanosaurs; anterior caudal centra that are amphicoelous, rather than procoelous; and a pedal phalangeal formula estimated as 2-2-3-2-0. These features are consistent with either an early-branching position within Titanosauria, or a position just outside the titanosaurian radiation, for Diamantinasauria, as indicated by alternative character weighting approaches applied in our phylogenetic analyses, and help to shed light on the early assembly of titanosaurian anatomy that has until now been obscured by a poor fossil record.
... Otherwise, Berriasian-Valanginian sauropod faunas in North America are dominated by turiasaurians [253,254], a group for which there is currently no Jurassic-or post-Valanginian-record in North America. Barremian-lower Aptian deposits in Utah have produced the brachiosaurid Venenosaurus [255] and indeterminate titanosauriforms [256,257], and lower Aptian deposits in Maryland have produced abundant evidence of titanosauriforms [258][259][260][261][262][263]. The nontitanosaurian somphospondylan Sauroposeidon (=Paluxysaurus) spans the Aptian-Albian of Texas and Oklahoma [221,[264][265][266][267][268], and possibly Arkansas [269]; other titanosauriforms recorded from this interval include indeterminate forms from Nevada, Montana and Wyoming [270][271][272][273][274], the brachiosaurid Abydosaurus [2] and the somphospondylan Brontomerus [64,275] from Utah, and a brachiosaurid possibly referable to Cedarosaurus [276][277][278], the somphospondylan Astrophocaudia [276,278] and indeterminate forms [276] from Texas. ...
The Upper Cretaceous Winton Formation of Queensland, Australia, has produced several partial sauropod skeletons, but cranial remains—including teeth—remain rare. Herein, we present the first description of sauropod teeth from this formation, based on specimens from three separate sites. An isolated tooth and a dentary fragment from the Diamantinasaurus matildae type locality are considered to be referable to that titanosaurian taxon. A single tooth from the D. matildae referred specimen site is similarly regarded as being part of that individual. Seventeen teeth from a new site that are morphologically uniform, and similar to the teeth from the two Diamantinasaurus sites, are assigned to Diamantinasauria. All sauropod teeth recovered from the Winton Formation to date are compressed-cone-chisel-shaped, have low slenderness index values (2.00–2.88), are lingually curved at their apices, mesiodistally convex on their lingual surfaces, and lack prominent carinae and denticles. They are markedly different from the chisel-like teeth of derived titanosaurs, more closely resembling the teeth of early branching members of the titanosauriform radiation. This provides further support for a ‘basal’ titanosaurian position for Diamantinasauria. Scanning electron microscope microwear analysis of the wear facets of several teeth reveals more scratches than pits, implying that diamantinasaurians were mid-height (1–10 m) feeders. With a view to assessing the spatio-temporal distribution of sauropod tooth morphotypes before and after deposition of the Winton Formation, we provide a comprehensive continent-by-continent review of the early titanosauriform global record (Early to early Late Cretaceous). This indicates that throughout the Early–early Late Cretaceous, sauropod faunas transitioned from being quite diverse at higher phylogenetic levels and encompassing a range of tooth morphologies at the start of the Berriasian, to faunas comprising solely titanosaurs with limited dental variability by the end-Turonian. Furthermore, this review highlights the different ways in which this transition unfolded on each continent, including the earliest records of titanosaurs with narrow-crowned teeth on each continent.
The Upper Cretaceous sauropod fossil record from Romania is abundant, mostly originated from the Maastrichtian deposits of the western-southwestern margin of the Transylvanian Basin, and in the Hațeg and Rusca Montana basins. Most specimens were found in isolation or in low degree of association and only few partial skeletons have been reported. The presence of at least four taxa was recently considered, including three defined forms: Magyarosaurus dacus, Paludititan nalatzensis and “Magyarosaurus” hungaricus. However, the phylogenetic affinities of these taxa within Lithostrotia are still under debate. A large sample of appendicular remains, predominantly composed by unpublished specimens, is described here in detail to provide new data about the diversity of the sauropods of the Hațeg Island during the Maastrichtian. All specimens show affinities or are compatible with lithostrotian sauropods, even if the availability of characters of some of them does not allow its attribution to this clade. Five morphotypes for the femora, three to four for the humeri, three for the fibulae, and two for the radii, ulnae, manus, pubes, ischia, tibiae, and pedes are established, supporting the presence of four or five taxa in this domain. A unique partial manus morphology characterized by its extreme gracile metacarpals is reported, only surpassed by an unpublished manus found in the Spanish Lo Hueco fossil-site (late Campanian-early Maastrichtian), suggesting that a titanosaurian lineage with extremely elongated manus inhabited the European realm, in both Hațeg and Ibero-Armorican islands, at the end of the Mesozoic.
The Upper Cretaceous fossil vertebrate fauna of the Bajo de la Carpa Formation (Santonian), derived from several different locations in the Neuquén Basin, is relatively abundant and diverse, comprising mainly small to medium-sized reptiles, birds and fishes. The Cerro Overo – La Invernada locality (CO – LI), in the north of the basin, records a similar faunal component for that age, but stands out for its relatively greater abundance and diversity of titanosaur sauropods. The study of the materials presented here allows us to establish the presence of specimens of sauropods other than Overosaurus, the only titanosaur recorded so far in the area, the coexistence of small–medium sized forms with larger forms, which in turn represent some forms with more basal characteristics and others with more derived features. The abundance of the record of sauropods in CO – LI shows both morphological and evolutionary variations, so the discovery of more complete specimens will allow paleofaunistic, paleobiological, and paleoecological studies to be carried out. This will provide a better understanding of the role of titanosaurian sauropods in Late Cretaceous ecosystems.
A new somphospondylan titanosauriform from the Lower Cretaceous of Spain is described from the remains found at the Sant Antoni de la
Vespa site (upper Barremian Arcillas de Morella Formation) located in Morella. Garumbatitan morellensis gen. et sp. nov. is diagnosed by 11
autapomorphies and eight local autapomorphies; and our phylogenetic analyses suggest that Garumbatitan morellensis might correspond to an
early-branching somphospondylan. The presence of several somphospondylan traits in Garumbatitan morellensis supports the somphospondylan
hypothesis. The phylogenetic distribution of some titanosauriform and somphospondylan novelties in the femur (markedly developed lateral
bulge, high shaft eccentricity, linea intermuscularis cranialis, and trochanteric shelf) is discussed. The tarsus and pes of Garumbatitan morellensis
are distinctive, being characterized by the loss of the calcaneum, relative slenderness of the metatarsals II, III, and IV when compared to the
retracted metatarsals I and V, three pedal phalanges in digit IV, and reduced ungual III. The sauropod fauna of the Iberian Peninsula during
the Hauterivian–Aptian shows a complex phylogenetic mosaic, including forms with Laurasian affinities, mainly titanosauriforms (Soriatitan,
Garumbatitan, and possibly Tastavinsaurus and Europatitan), and Gondwanan affinities, the rebbachisaurid Demandasaurus. Faunal exchange
during the Early Cretaceous between the Europe, North America, East Asia, and Africa is plausible.
Osteological knowledge of the sauropod dinosaur Ligabuesaurus leanzai is increased by the description of new postcranial elements assigned to the holotype MCF-PVPH-233. Furthermore, a newly referred specimen, MCF-PVPH-228, is recognized after a detailed revision of the abundant sauropod material collected from the Lohan Cura Formation outcrops in the Cerro de los Leones locality (southern Neuquén Basin, Patagonia, Argentina). Recent laboratory preparation and fieldwork allowed us to recognize several new morphological features of the pectoral and pelvic girdles and the cervical and caudal anatomy. Thus, a new diagnosis of Ligabuesaurus is proposed that includes new autapomorphies and a unique combination of features. A phylogenetic analysis based on this new material recovers Ligabuesaurus as a non-titanosaurian somphospondylan, more derived than Sauroposeidon. Therefore, we discuss the palaeobiogeographical implications for the diversification and distribution of South American somphospondylans, especially in the Neuquén Basin, which are closely related to the early stages of evolution of Titanosauria. In this context, Ligabuesaurus represents one of the more complete Early Cretaceous Titanosauriformes and the earliest non-titanosaurian somphospondylan of South America. Finally, the new information on Ligabuesaurus contributes not only to reconstruction of the sauropod faunal composition of south-western Gondwana, but also sheds light on the early stages and emergence of titanosaurians.
Ankylosaurs are relatively common in the Cedar
Mountain Formation and include (1) Gastonia burgei,
(2) Sauropelta sp., and (3) Animantarx ramaljonesi new
genus, new species. Animantarx ramaljonesi is characterized
by a highly domed cranium, very small postorbital
"horns," moderately developed lateral notch in the
skull roof for the lateral temporal fenestra, indistinguishable
pattern of armor on the skull roof, small quadratojugal
"hom," elongated coracoid that is about 63% of
the scapula length, a high shoulder on the deltopectoral
crest, and an oblique ridge on anterolateral surface of the
femur below the lesser trochanter.
The Cedar Mountain ankylosaurs appear to be
restricted to distinct stratigraphic units: Gastonia burgei
to the Yellow Cat Member, Sauropelta sp. to the Poison
Strip Sandstone, and Animantarx ramaljonesi to the
Mussentuchit Member. Provisionally, such a distribution
supports a threefold division of the Cedar
Mountain dinosaur faunas. The diversity of
ankylosaurs in the Cedar Mountain is the
highest of any Lower Cretaceous formation
and may eventually provide important information
about the evolution and adaptive radiation
of these dinosaurs.
Preparation of an approximately two-thirds complete, well-preserved Camarasaurus skeleton has recently been finished. Its detailed osteological description presented here provides a number of interesting characters, some not previously reported for the genus. This specimen (BYU 9047) was earlier named Cathetosaurus lewisi, n. gen. et sp., based on seven characters cited by Jensen (1988). Of these characters, four appear to be age related (this skeleton represents a very old individual) and not of taxonomic significance. Nevertheless, they are useful in advancing our understanding of the ligamentation associated with the sacral and posterior dorsal regions, not only of Camarasaurus but of the sauropods in general. These characters also contribute to a greater knowledge of the ontogenetic development and fusion of the sacral elements. Camarasaurus lewisi (Jensen, 1988) is a valid species whose diagnostic characters include (1) a deep but narrow cleft in the neural spines of presacral vertebrae, which most significantly persists to the sacrum rather than ending in the mid-dorsal region, as in all other species of Camarasaurus; (2) a forward rotation of the ilium with respect to the long axis of the sacrum, a hitherto unreported major character of the genus Camarasaurus; and (3) a steep angle that the posterior chevron articulating facets make with the horizontal plane.
Studies of a complete left pes of the Texas Lower Cretaceous sauropod, Pleurocoelus sp. indet., show-on the basis of the form and size of the elements, particularly the claws-some adaptations for scratch-digging. Four distinct claws are associated with the pedal skeleton, supporting the view that this species was at least one of the Glen Rose trackmakers. Evidence presented here allies Pleurocoelus with the brachiosaurids.
Chubutisaurus insignis Del Corro (1975) from the Aptian Gorro Frigio Formation) of Chubut Province, Argentina, is a large sized dinosaur having controversial phylogenetic relationships within the Sauropoda. Orginally it was regarded as a member of a new family (Chubutisauridae) because of the amphiplatyan caudal vertebrae. Chubutisaurus insignis was then distinguished from the well-known and widely reported Late-Cretaceous titanosaurids, characterized by procoelous caudal vertebrae. Finally, it was suggested to include Chubutisaurus insignis within the Brachiosauridae because it shares several characters with Brachiosaurus and other members of the group. The holotype of Chubutisaurus insignis is here redescribed and interpreted. Probable affinities of this fossil are discussed adding information to the faunal characteristics of the mid-Cretaceous of Gondwana. -from Author
Remains assigned to Aeolosaurus Powell, 1986 from the Allen Formation are described. The specimen differs from the holotype of Aeolosaurus rionegrinus Powell, 1986 in the length of the prezigapophyses, relative position of the postzigapophyses, and radius and ischium morphology. Considerations on a specimen tentatively assigned to the type species, and modified diagnosis of genus are included. Association of dermal plates to the specimen here described is commented. -English summary
