Assignation of the Vertebra Cpp 494 to Trigonosaurus Pricei

Bol. Mus. Nac. Hist. Nat. Parag. Vol. 17, nº 1 (Ago. 2013): 100-10020-28

ASSIGNATION OF THE VERTEBRA CPP 494 TO TRIGONOSAURUS PRICEI CAMPOS ET AL., 2005 (SAUROPODA: TITANOSAURIFORMES) FROM THE LATE CRETACEOUS OF BRAZIL, WITH COMMENTS ON THE LAMINAR VARIATION AMONG LITHOSTROTIAN TITANOSAURS

Rubén D. Juárez Valieri1 & Sergio D. Ríos Díaz2,3

1Secretaría de Cultura de la Provincia de Río Negro, General Roca, Río Negro, Argentina. E-mail: [email protected] 2Secretaría Nacional de Cultura. Dirección de Bienes Culturales, Asunción, Paraguay. E-mail: [email protected] 3Museo Nacional de Historia Natural del Paraguay, Sucursal 1 Campus, Central XI, San Lorenzo, Paraguay.

Abstract.- A revision of material corresponding to a posterior dorsal vertebra of a titanosaurian sauropod dinosaur, CPP 494, is made. It comes from the Serra da Galga Member, Marília Formation, near the locality of Peirópolis, Minas Gerais Estate, Brazil. This material was originally described in 2006, as belonging to an undetermined titanosaur, but distinguishable from known species on the basis of characters related to the laminar configuration and the development of the dorsal portion of the diapophysis. A detailed comparison of the material leads to reconsider these supposed differences as variations in the dorsal axial sequences, thus allowing assigning the vertebra CPP 494 to Trigonosaurus pricei Campos et al., 2005, which is stratigraphically and geographically close. The issue of taxonomic differentiation based on axial characters described from isolated elements, without considering the sequential variation, is briefly discussed. Key words: Trigonosaurus pricei, dorsal vertebra, sequential variation.

Resumen.- Se realiza una revisión de material correspondiente a una vértebra dorsal posterior de dinosaurio saurópo- do titanosaurio, CPP 494. El mismo procede del Miembro Sierra da Galga, Formación Marília, de las cercanías de la localidad de Peirópolis, Estado de Minas Gerais, Brasil. Este material fue originalmente descrito en 2006, como correspondiente a un titanosaurio indeterminado, pero distinguible de las especies conocidas por una serie de características relacionadas a la conformación laminar y al desarrollo de la cara dorsal de las diapófisis. Una comparación detallada del material lleva a reconsiderar estas supuestas diferencias como variaciones existentes dentro de las secuencias axiales dorsales, permitiendo de este modo asignar la vértebra CPP 494 a Trigonosaurus pricei Campos et al., 2005, el cual es muy próximo tanto geográfica como estratigráficamente. Se discute brevemente la problemática de la diferenciación taxonómica basada en caracteres axiales descritos a partir de elementos aislados, sin considerarse la variación secuencial. Palabras clave: Trigonosaurus pricei, vértebra dorsal, variación secuencial.

As usual in derived sauropod dinosaurs, the son, 2012). lithostrotian titanosaurs display complex neu- In the present work, we discuss the taxo- ral arches with multiple laminae and fossae in nomic significance of the laminar complex the dorsal vertebrae (Salgado et al., 2006; Sal- of a dorsal vertebra (CPP 494) from the Late gado & Powell, 2010). Variation in the configu- Cretaceous of Brazil, previously described by ration of the laminar neural arch is commonly Santucci & Bertini (2006). Here we focus the used in the determination of specific taxa or comparison with the stratigraphically and geo- used as synapomorphies of more inclusive cla- graphically close titanosaurs Trigonosaurus des (McIntosh, 1990; Salgado et al., 1997; Bo- pricei Campos et al. (2005) and Uberabatitan naparte, 1999; Wilson, 2002; Upchurch et al., riberoi Salgado & Carvalho (2008). Additio- 2004; Curry Rogers, 2005; Carballido et al., nally, the variation of the laminar complex in 2011a; D’Emic, 2012; Mannion et al., 2013), both articulated and incompletely known dor- but the implications of the sequential variation sal sequences, and the validity of characters are poorly analyzed for many taxa and can lead associated with them, are discussed for lithos- to errors in systematics (see discussion in Wil- trotian titanosaurs.

Artículo Boletín del Museo nacional de Historia Natural del Paraguay Vol. 17, Nº 1 (Agosto 2013) 21

Institutional Abbreviations the last dorsal, an articulated sacrum with ilium Argentina and several anterior and middle caudals. MAU: Museo Argentino Urquiza, Rincón de Prior to the erection of the genus and spe- Los Sauces, Neuquén cies, this titanosaur has been commonly utili- MCS: Museo Municipal de Cinco Saltos, zed in cladistic analysis (Salgado et al., 1997; Cinco Saltos, Río Negro Sanz et al., 1999, Powell, 2003; Curry Rogers, MPCA: Museo Provincial Carlos Ameghino, 2005). Shortly after, two posterior dorsal verte- Cipolletti, Río Negro. brae, CPP 491 (a centrum) and 494 (a complete MUCPv: Museo de la Universidad Nacional del vertebra) were described by Santucci & Bertini Comahue, Neuquén, Neuquén. (2006) as an unnamed, large titanosaur. They UNPSJB: Universidad Nacional de la Patagonia distinguished it from any previously described San Juan Bosco, Comodoro Rivadavia, advanced titanosaur based on the absence of Chubut. ventral widening or bifurcation of the posterior centrodiapophyseal laminae (pcdl). Additional Brazil differences were reported between the CCP CPP: Centro de Pesquisas Paleontológicas material and Trigonosaurus pricei, including Llewelyn Ivor Price, Peirópolis, Minas the existence of postzygaodiapophyseal lami- Gerais. nae (podl), and the presence of a large area for MCT: Museu de Ciências da Terra, muscular attachment on the dorsal portion of Departamento Nacional de the diapophyses. Produção Mineral, Rio de Janeiro. Lately, a new titanosaur was erected by Anatomical Abbreviations Salgado & Carvalho (2008), Uberabatitan riberoi, represented by three specimens, and acdl: anterior centrodiapophyseal lamina. apcdl: accessory posterior centrodiapophyseal includes axial and appendicular material, the- lamina. reby allowing comparison with many of the aprl: accessory prespinal lamina. other South American titanosaurs. Salgado & aspdl: anterior spinodiapophyseal lamina. Carvalho (2008) considered that CPP 491 and pcpl: posterior centroparapophyseal lamina. 494 probably belong to Uberabatitan or to a podl: postzygodiapophyseal lamina. closely related form, as they mentioned a few prl: prespinal lamina. similarities (alongside several differences) bet- pspdl: posterior spinodiapophyseal lamina. ween them, but no formal association was pro- spdl: spinodiapophyseal lamina. posed. sprl: spinoprezygapophyseal lamina. All the material previously mentioned was BACKGROUND recovered in nearby sites north of the Peirópo- lis locality, Minas Gerais State, southeastern The lithostrotian sauropod Trigonosaurus Brazil, and corresponding to different levels pricei was named by Campos et al. (2005) and, of the Serra da Galga Member, Marília For- to this date, is one of the most complete titano- mation, upper unit of the Bauru Group, Late saur taxon found in Brazil. The partial skeleton Cretaceous. that constitutes the holotype (MCT 1488-R) Despite the abundance of lithostrotian sau- and the associated paratype (MCT 1719-R) ropods in the South American fossil record was previously known as DGM “series B” in (Mannion & Otero, 2012), individuals preser- the literature (Powell, 1987, 2003; Campos ving the complete dorsal axial sequence are & Kellner, 1999). It comprises an articulated rare, and only a few known taxa provide subs- axial sequence from the posterior cervicals to tantial information about the sequential varia-

Assignation of the vertebra CPP 494 to Trigonosaurus pricei from the late cretaceous of Brazil 22 Boletín del Museo nacional de Historia Natural del Paraguay Vol. 17, Nº 1 (Agosto 2013) tion in the configuration of the neural arches. veral laminae of the neural arch (Fig. 1). Among South American forms, besides the Santucci & Bertini (2006) differenciated Trigonosaurus pricei holotype, only three spe- CPP 494 from Trigonosaurus pricei based on cimens preserve the complete dorsal axial se- the presence of postzygodiapophyseal lamina quence: Overosaurus paradasorum (MAU-Pv- (podl), centrodiapophyseal laminae not wide- CO-439; Coria et al., 2013), Futalognkosaurus ned ventrally, and the presence of a large area dukei (MUCPv 323, Calvo et al., 2008a), and for muscular attachment on the dorsal portion an undescribed species from the Late Creta- of the diapophysis in CPP 494. ceous of Neuquén province (MAU-PV-AC-01, Regarding the first character, although this Calvo et al. 1997). lamina is absent in most of the dorsal verte- The last two specimens are actually not brae of MCC 1488-R, in the tenth vertebra a available for comparisons, since their dorsal prominent lamina connecting the diapophysis axial sequences remain unpublished or brie- with the postzygapohysis was identified, des- fly described. Partial dorsal axial sequences cribed and figured as the podl in Campos et al. are also known for Epachthosaurus sciuttoi (2005). In fact, the existence of an incipient (UNPSJB-PV 920; Martínez et al., 2004), Neu- podl in the two posteriormost dorsal vertebrae quensaurus australis (MCS-5; Salgado et al., is even included in the original diagnosis of 2005), and Bonitasaura salgadoi (MPCA-460; Trigonosaurus pricei. Salgado et al. (2006) Gallina 2011). reinterpreted it as an accessory unnamed lami- Some other taxa preserve multiple dorsal na, but more recently Salgado & Powell (2010) elements, such as Argentinosaurus huinculen- objected to this interpretation and considered sis, but the correct position of the vertebrae in it as a true podl. Here we agree in interpreting the sequence is problematic (Novas & Ezcu- this lamina as a podl. Regardless of the identity rra, 2006), restricting their comparative value. of this lamina in Trigonosaurus, it is evident Other taxa are represented by multiple speci- that the same structure is present in CPP 494, mens that were recovered mixed in the same displaying the same position, direction and quarry, obscuring the assignation to particular length. individuals, such as in Saltasaurus loricatus or In relation to the second character, the abs- Muyelensaurus pecheni (Powell, 1992; Calvo ence in CPP 494 of “widening or bifurcation” et al., 2008b). of the posterior centrodiapophyseal laminae, Here we follow Wilson (1999) and Salgado supposedly opposite to the condition of Andes- & Powell (2010) regarding the anatomical no- aurus and more derived titanosaurs as propo- menclature of the laminae present in the titano- sed by Salgado et al. (1997), is rejected becau- saurian dorsal vertebrae. se the same character state is found in the last two dorsal vertebrae of Trigonosaurus pricei RESULTS AND DISCUSSION (see below). This character can be better stated Comparison between the holotype of Trigo- as the presence of an accessory posterior cen- nosaurus pricei and CPP 494 trodiapophyseal lamina (apcdl) reaching the The overall general shape and disposition of dorsocranial region of centrum, as proposed the centrum and neural arch in CPP 494 is by Salgado et al. (2005), or a modified anterior similar to the most posterior dorsals of MCT centrodiapophyseal lamina (acdl) (i.e. Wilson 1488-R. Particular resemblance is displayed & Upchurch, 2009). with the T. pricei tenth dorsal, since both have Since in the caudalmost dorsal vertebrae the the same relative position of the diapophyses pcpl expand their posterior length to reach clo- and parapophyses, the neural spine and the se- se to the caudodorsal area of the centrum, the

R. D. Juárez Valieri & S. D. Ríos Díaz Boletín del Museo nacional de Historia Natural del Paraguay Vol. 17, Nº 1 (Agosto 2013) 23

Figure 1. A. Trigonosaurus pricei posteriormost dorsal vertebrae. A1, ninth and tenth elements of MCT 1488-R in left lateral view; A2, tenth element of CPP 494 in left lateral view; A3, the same in right lateral view. B. Development of the principal lateral laminae discussed in the text. C. Comparison among the distribution of the laminae in: C1, ninth of MCT 1488-R; C2, tenth of MCT 1488-R; C3, tenth of CPP 494.

Assignation of the vertebra CPP 494 to Trigonosaurus pricei from the late cretaceous of Brazil 24 Boletín del Museo nacional de Historia Natural del Paraguay Vol. 17, Nº 1 (Agosto 2013)

pertaining to the presence of a large area for muscular attachment on the dorsal portion of the diapophysis, is also present in the ninth and tenth dorsal of Trigonosaurus, which are clearly visible in dorsal view (Powell 2003, pl. 15, fig. 5). In fact, this feature characterizes most somphospondylians (Sanz et al., 1999; D’Emic, 2012). The existence of an anterior spinodiapophyseal lamina (aspdl) (or a displaced postzygodiapophyseal lamina (podl) sensu Salgado et al. 2006) was reported on the right side of the neural arch of CPP 494. It was interpreted as an abnormality by Santucci and Bertini (2006, p. 355). Salgado and Carvalho (2008) interpreted this as equivalent to their podl+spdl (here Figure 2. Trigonosaurus pricei holotype MCT aspdl+pspdl), that is present in Uberabatitan 1488-R, tenth dorsal vertebra in left posterola- riberoi and Trigonosaurus pricei. In the holo- teral view. Based on Campos et al. (2005). Ab- type of Trigonosaurus pricei the aspdl+pspdl breviations: aspdl: anterior spinodiapophyseal complex is prominent from the fifth to the lamina; pspdl: posterior spinodiapophyseal la- eight dorsal vertebrae as reported by previous mina. authors, although here we note the presence of the two lamina in the tenth dorsal vertebra too apcdl (or acdl) is restricted to a higher area of (Fig. 2). Thus, if CPP 494 is considered homo- the neural arch as in Overosaurus and Rape- logous to the tenth dorsal of MCC 1488-R and tosaurus, or laking, as in Trigonosaurus, Neu- belonging to the same taxon, the existence of quensaurus, Saltasaurus and Muyelensaurus the aspdl+pspdl complex in the left face should (Coria et al., 2013; Curry Rogers, 2009; Sal- be considered as result of individual variation. gado et al., 2005; Powell, 1992; Juárez Valieri, This assumption is supported by the mor- pers. obs.). The assumption of the presence of phology of the right side of the neural arch of this character as synapomorphic of Titanosau- CPP 494, which is agrees with the morphology ria has to be dismissed, since it is present in present in the Trigonosaurus pricei holotype. more basal somphospondylians and even basal Other reports of lithostrotian titanosaurs with macronarians (Carballido et al., 2011b; Man- asymmetrical configuration of the laminar nion et al., 2013) and reviewed in their precise complex in dorsal vertebrae were given for definition, restricting their validity to anterior Pitekunsaurus macayai (Filippi & Garrido, to middle dorsal vertebrae. 2008), undescribed titanosaur material from Then, the absence of the apcdl in CPP 494 Marília (Santucci & Bertini, 2006), and is also is considered here as evidence of its caudal po- present in other species such as Muyelensaurus sition among dorsals. In fact, the morphology, pecheni (Fig. 3), Rinconsaurus caudamirus length, and placement of the centrodiapophy- and Bonitasaura salgadoi (MAU-PV-9 and seal laminae are the same between the tenth MPCA-460; Juárez Valieri, pers. obs.; Gallina dorsal vertebra of MCC 1488-R and CPP 494. 2011). Finally, the third character proposed as A striking feature of CPP 494 is the presen- differentiating MCC 1488-R and CPP 494, ce of two paired laminae, parallel to the pres-

R. D. Juárez Valieri & S. D. Ríos Díaz Boletín del Museo nacional de Historia Natural del Paraguay Vol. 17, Nº 1 (Agosto 2013) 25

Figure 3. A. Posterior dorsal vertebra of Trigonosaurus pricei, CPP 494 in anterior view. B. Posterior dorsal vertebra of Muyelensaurus pecheni, MAU-PV-412 in anterior view. Not to the same scale. Abbreviations: aprl: accessory prespinal lamina; aspdl: anterior spinodiapophyseal lamina; prl: prespinal lamina. pinal lamina (prl). Santucci & Bertini (2006) as accessory prespinal laminae (aprl) as in San- considered these as “accessory prespinal lami- tucci & Bertini (2006), since it is not possible na”. Salgado & Carvalho (2008) suggested that to confirm their homology with the true sprl. these elements could be homologous with the The presence of the aprl in the tenth dorsal spinoprezygapophyseal laminae. The sprl is vertebra of Trigonosaurus holotype cannot be commonly recorded in the cranialmost dorsal determined as it is in contact with the precedent vertebrae of lithostrotians, and has been repor- element. It is clear that these accessory ele- ted in the mid-dorsal elements of Uberabatitan ments are present in CPP 494, MAU-PV-412, riberoi. and the larger Uberabatitan specimens, all Personal observation of the Muyelensaurus being putatively adults individuals, so they pecheni material, housed in the MAU collec- maybe can be considered as structures of addi- tion, allows us to describe a posterior dorsal tional support to the ligaments which develop vertebra (MAU-PV-412), possibly the ninth or in mature ontogenetic stages. tenth element based on the laminar composi- tion and relative position of the neural spine, CONCLUSION diapophysis and parapophysis, displaying the The presence, orientation and shape of the la- two laminae parallel to the prl (Fig. 2). As no- minae and fossae displayed in the neural arch, ted in Calvo et al. (2008b), some of the poste- and the shape of the centrum and pleurocoel rior dorsal vertebrae of Muyelensaurus display of the dorsal vertebra CPP 494, is concordant two short laminae that join at the base of the with the last dorsal of Trigonosaurus pricei, prl, displaying a triradiate structure, which are and thus CPP 494 is assigned to this taxon. The treated as accessory laminae. These short lami- presence of an additional, larger specimen of nae are here interpreted as homologous to the Trigonosaurus pricei is not unexpected, as it condition present in CPP 494, and considered was recovered in a locality very near from that

Assignation of the vertebra CPP 494 to Trigonosaurus pricei from the late cretaceous of Brazil 26 Boletín del Museo nacional de Historia Natural del Paraguay Vol. 17, Nº 1 (Agosto 2013) of the holotype and belongs to the same levels Calvo, J.O., B.J. González Riga & J.D. Porfiri. of the Marilia Formation. 2008b. A new titanosaur sauropod from Based on the strong changes in the confi- the Late Cretaceous of Neuquén, Pata- guration of the neural arch along the dorsal gonia, Argentina. Arquivos do Museu sequences observed in more complete titano- Nacional, 65(4): 485-504. saurian taxa, the necessity of review of several Campos, D. & A.W.A. Kellner. 1999. On some characters currently used in cladistic analysis sauropod (Titanosauridae) pelves from of lithostrotian or even titanosaurian sauropods the continental Cretaceous of Brazil. is evident. Lastly, extreme caution is suggested National Science Museum Monographs, in the codification of axial characters for taxa 15: 143-166. where complete sequences are unknown. Campos, D.A., A.W.A. Kellner, R.J. Bertini & R.M. Santucci. 2005. On a titanosaurid ACKNOWLEDGMENTS (Dinosauria, Sauropoda) vertebral co- The authors wish to acklowledge Flavio Be- lumn from the Bauru Group, Late Cre- llardini, Lucas Fiorelli, Augusto Haro and Phi- taceous of Brazil. Arquivos do Museu lip Mannion for their helpful review sugges- Nacional, 63(3): 565-596. tions and comments, which greatly improved Carballido, J.L., O.W.M. Rauhut, D. Pol, & L. the original manuscript. To Rubén Barbieri Salgado. 2011a. Osteology and phyloge- (Museo Carlos Ameghino, Cipolletti), Leo- netic relationships of Tehuelchesaurus nardo Filippi (Museo Argentino Urquiza, Rin- benitezii (Dinosauria, Sauropoda) from cón de Los Sauces), Jorge O. Calvo (Centro the Upper Jurassic of Patagonia. Zoo- Paleontológico Lago Barreales, Universidad logical Journal of the Linnean Society, Nacional del Comahue, Neuquén) and Ignacio 163: 605-662. Cerda (Museo Municipal de Cinco Saltos) for Carballido, J.L., O.W.M. Rauhut, D. Pol & L. access to specimens under their care. Finally, Salgado. 2011b. Osteology and phyloge- to Rodrigo M. Santucci and Rosie Barnes, for netic relationships of Tehuelchesaurus providing us with photographs of the CPP and benitezii (Dinosauria, Sauropoda) from MAU specimens, respectively. the Upper Jurassic of Patagonia. Zoo- logical Journal of the Linnean Society, LITERATURE 163: 605-662. Bonaparte, J.F. 1999. Evolución de las vérte- Coria, R.A., L.S. Filippi; Chiappe, L.M.; Gar- bras presacras en Sauropodomorpha. cía, R.A. & Arcucci, A. B. 2013. Ove- Ameghiniana, 36(2): 115-187. rosaurus paradasorum gen. et sp. nov., Calvo, J.O., R.A. Coria & L. Salgado. 1997. a new sauropod dinosaur (Titanosauria: Uno de los más completos titanosáuri- Lithostrotia) from the Late Cretaceous dos (Dinosauria, Sauropoda) registrados of Neuquén, Patagonia, Argentina. Zoo- en el mundo. Ameghiniana, 34(4): 534. taxa, 3683(4): 357-376. Calvo, J.O., J.D. Porfiri, B.J. González Riga Curry Rogers, K.A. 2005. Titanosauria: A & A.W.A. Kellner. 2008a. Anatomy of Phylogenetic Overview. In K.A. Curry Futalognkosaurus dukei Calvo, Por- Rogers & J.A. Wilson (Eds.): The Sau- firi, González Riga & Kellner, 2007 ropods: Evolution and Paleobiology, pp. (Dinosauria, Titanosauridae) from the 50-103. Neuquén Group (Late Cretaceous), Pa- Curry Rogers, K.A. 2009. The Postcranial Os- tagonia, Argentina. Arquivos do Museu teology of Rapetosaurus krausei (Sau- Nacional, 65(4): 511-526. ropoda: Titanosauria) from the Late

R. D. Juárez Valieri & S. D. Ríos Díaz Boletín del Museo nacional de Historia Natural del Paraguay Vol. 17, Nº 1 (Agosto 2013) 27

Cretaceous of Madagascar. Journal of Titanosauridae). XXII Jornadas Argen- Vertebrate Paleontology, 29(4): 1046- tinas de Paleontología de Vertebrados. 1086. 48R-49R. D’Emic, M.D. 2012. The early evolution of ti- Powell, J.E. 1987. Morfología del esqueleto tanosauriform sauropod dinosaurs. Zoo- axial de los dinosaurios titanosauridos logical Journal of the Linnean Society, (Saurischia, Sauropoda) del estado de 166(3): 624-671. Minas Gerais, Brasil. 10° Congresso Filippi, L.S. & A.C. Garrido. 2008. Pitekun- Brasileiro de Paleontologia, Anais: 155- saurus macayai gen. et sp. nov., Nuevo 171. titanosaurio (Saurischia, Sauropoda) del Powell, J.E. 1992. Osteología de Saltasaurus Cretácico Superior de la Cuenca Neu- loricatus (Sauropoda - Titanosauridae) quina, Argentina. Ameghiniana, 45(3): del Cretácico Superior del noroeste 575-590. Argentino. Pp. 165-230. En: Los dino- Gallina, P.A. 2011. Notes on the axial skeleton saurios y su entorno biótico: Actas del of the titanosaur Bonitasaura salgadoi. Segundo Curso de Paleontologia en Anais da Academia Brasileira de Ciên- Cuenca. cias, 83(1): 235-246. Powell, J.E. 2003. Revision of South American Mannion, P.D. & A. Otero. 2012. A reappraisal Titanosaurid dinosaurs: palaeobiologi- of the Late Cretaceous Argentinean sau- cal, palaeobiogeographical and phyloge- ropod dinosaur Argyrosaurus superbus, netic aspects. Records of the Queen Vic- with a description of a new titanosaur toria Museum, New Series, 111: 1-173. genus. Journal of Vertebrate Paleontolo- Salgado, L. & I. de S. Carvalho. 2008. Ube- gy, 32(3): 614-638. rabatitan ribeiroi, a new titanosaur from Mannion, P.D., P. Upchurch, R.N. Barnes, & the Marília Formation (Bauru Group, O. Mateus. 2013. Osteology of the Late Upper Cretaceous), Minas Gerais, Bra- Jurassic Portuguese sauropod dinosaur zil. Palaeontology, 51(4): 881-901. Lusotitan atalaiensis (Macronaria) and Salgado, L., R.A. Coria & J.O. Calvo. 1997. the evolutionary history of basal tita- Evolution of titanosaurid sauropods. I: nosauriforms. Zoological Journal of the Phylogenetic analysis based on the post- Linnean Society, 168(1): 98-206. cranial evidence. Ameghiniana, 34(1): Martínez, R.D., O. Giménez, J. Rodríguez, 3-32. M. Luna & M.C. Lamanna. 2004. An Salgado, L., S. Apesteguía & S.E. Heredia. articulated specimen of the basal ti- 2005. A new specimen of Neuquen- tanosaurian (Dinosauria: Sauropoda) saurus australis, a Late Cretaceous sal- Epachthosaurus sciuttoi from the early tasaurine titanosaur from North Patago- Late Cretaceous Bajo Barreal Formation nia. Journal of Vertebrate Paleontology, of Chubut Province, Argentina. Journal 25(3): 623-634. of Vertebrate Paleontology, 24(1): 107- Salgado, L., R.A. García & J.D. Daza. 2006. 120. Consideraciones sobre las láminas neu- McIntosh, J.S. 1990. Sauropoda. In D.B. Weis- rales de los dinosaurios saurópodos y su hampel, P. Dodson, & H. Osmólska significado morfofuncional. Revista del (Eds.), The Dinosauria, pp. 345-401. Museo Argentino de Ciencias Naturales Novas, F.E. & M.D. Ezcurra. 2006. Reinter- “Bernardino Rivadavia” (nueva serie), pretation of the dorsal vertebrae of Ar- 8(1): 69-79. gentinosaurus huinculensis (Sauropoda, Salgado, L., & J.E. Powell. 2010. Reassessment

Assignation of the vertebra CPP 494 to Trigonosaurus pricei from the late cretaceous of Brazil 28 Boletín del Museo nacional de Historia Natural del Paraguay Vol. 17, Nº 1 (Agosto 2013)

of the vertebral laminae in some South 322. American titanosaurian sauropods. Jour- Wilson, J.A. 1999. A nomenclature for verte- nal of Vertebrate Paleontology, 30(6): bral laminae in sauropods and other sau- 1760-1772. rischian dinosaurs. Journal of Vertebrate Santucci, R.M. & R.J. Bertini. 2006. A large Paleontology, 19(4): 639-653. sauropod titanosaur from Peirópolis, Wilson, J.A. 2002. Sauropod dinosaur phylo- Bauru Group, Brazil. Neues Jahrbuch geny: critique and cladistic analysis. für Geologie und Paläontologie Monats- Zoological Journal of the Linnean So- hefte, 2006(6): 344-360. ciety, 136: 217-276. Sanz, J.L., J.E. Powell, J. Le Loueff, R. Mar- Wilson, J.A. 2012. New vertebral laminae and tínez & X. Pereda-Suberbiola. 1999. patterns of serial variation in vertebral Sauropod remains from the Upper Cre- laminae of sauropod dinosaurs. Contri- taceous of Laño (Northcentral Spain). butions from the Museum of Paleontolo- Titanosaur phylogenetic relationships. gy, University of Michigan, 32: 91-110. Estudios del Museo de Ciencias Natura- Wilson, J. A., & P. Upchurch. 2009. Redes- les de Alava, 14(N.E.1): 235-255. cription and reassessment of the phylo- Upchurch, P., P.M. Barrett & P.D. Dodson. genetic affinities of Euhelopus zdanskyi 2004). Sauropoda. In D.B. Weishampel, (Dinosauria: Sauropoda) from the Early P. Dodson, & H. Osmólska (Eds.), The Cretaceous of China. Journal of Syste- Dinosauria, Second Edition, pp. 259- matic Palaeontology, 7(2): 199-239.

R. D. Juárez Valieri & S. D. Ríos Díaz