Wednesday, September 14, 2016

The caudofemoral musculature on the titanosaurian tail skeleton


Comments about the paper titled:

The influence of caudofemoral musculature on the titanosaurian (Saurischia: Sauropoda) tail skeleton: morphological and phylogenetic implications

Authors: Lucio M. Ibiricu, Matthew C. Lamanna & Kenneth J. Lacovara

Reference: Lucio M. Ibiricu, Matthew C. Lamanna & Kenneth J. Lacovara (2014) The influence of caudofemoral musculature on the titanosaurian (Saurischia: Sauropoda) tail skeleton: morphological and phylogenetic implications, Historical Biology, 26:4, 454-471, DOI: 10.1080/08912963.2013.787069



This is an interesting and smart paper about the anatomy of caudal vertebrae of titanosaurs. The authors reconstruct the morphology and interpret the implications of selected soft-tissues associated with the titanosaurian caudal skeleton. These tissues, especially the M. caudofemoralis longus (CFL), exerted a considerable influence on the anatomy of the caudal vertebrae and haemal arches. 

The authors propose the existence of three general evolutionary states in titanosaurian proximal caudal vertebrae: (1) a protuberance on the lateral aspect of the vertebrae that persists until at least caudal 20 (considered state 0), (2) a primary lateral surface that becomes dorsoventrally narrow distally and is replaced by the secondary lateral surface at approximately caudal 9–12 (considered state 1) and (3) a rim that migrates across the lateral aspect of the centrum, becoming situated on its ventrolateral corner at about caudal 8 (considered state 2). These three states may easily be rephrased as a character statement for use in phylogenetic analysis, as follows: ‘morphology of lateral aspect of proximal and middle caudal vertebrae: transverse process or rudimentary transverse process persists until at least caudal 20 (0); primary lateral surface replaced by secondary lateral surface at approximately caudal 9–12 (1); low rim migrates ventrally across lateral surface of centrum,  terminating on ventrolateral corner at approximately caudal 8 (2).’


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The caudal vertebrae of titanosaurs are the most abundant skeletal elements in the fossil record (González Roga, 2011). In the last years, papers on osteology and miology give us new phylogenetic and functional information.  

Reference: Gonzalez Riga BJ. 2011. Paleontologıa y dinosaurios desde America Latina: Proceedings del III Congreso Latinoamericano de Paleontologıa. In: Calvo J, Porfiri J, Gonzalez Riga BJ, Dos Santos D, editors. Paleobiology of South American titanosaurs. Mendoza: Universidad Nacional de Cuyo. p. 125–141.



  LABORATORIO Y MUSEO DE DINOSAURIOS DE LA UNIVERSIDAD NACIONAL DE CUYO: FUNDACIÓN, HISTORIA Y DESCUBRIMIENTOS CIENTÍFICOS BERNARDO J. GONZÁ...