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The relationships among basal sauropodomorphs are controversial. Results of cladistic analyses vary from a fully paraphyletic assemblage to a monophyletic core‐prosauropod. We apply the comparative cladistics method to three published cladistic analyses of sauropodomorph dinosaurs, in order to identify root causes for differences between phylogenetic results. Except for three taxa (Saturnalia, Thecodontosaurus, and Efraasia) and one clade (Gravisauria), the remaining genera are recovered with conflicting positions. The comparative method is based on indices that allow for the quantification of the degree of similarity in characters and character states among analyses. A comparison of primary data, character selection, and scoring highlights significant discrepancies in data sets. Our results suggest that one character out of two varies from one analysis to the other. These are the root causes for the phylogenetic incongruence observed. The hurdle of the phylogenetic definition of the clade Sauropoda, which has been defined in four different ways, is also treated. We concur with several recent papers following the first node‐based definition of Sauropoda. © 2015 The Linnean Society of London

Fabre and Christiane Mendrez (MNHN) (Table 1). The expedition was followed by the first description of the bones of the Maphutseng dinosaur, and their attribution to Euskelosaurus browni (Ellenberger and Ginsburg, 1966).In September 1970, P. Ellenberger oversaw the last expedition in Maphutseng, with the assistance of L. Ginsburg, J. Fabre and Bernard Battail (MNHN) (Table 1; Fig. 2). The bones collected were brought to Paris. Between 1959 and 1970, based on the excavation plan of 1959 and the total number of excavated pieces given by P. Ellenberger (Ellenberger, 1970: 345), we estimate to approximately 400 the number of Maphutseng fossils sent to France. The brothers Ellenberger attributed a field number to each excavated bone between 1959 and 1970. Given that the numbers range from 684 to 1303, the number of fossils is extended to 600. However, only 210 are nowadays housed in the MNHN, in Paris. This significant difference can be explained if we consider that, on the field, several numbers can be attributed to fragments of the same bone. Consequently, some subcomplete bones of the collections display until 4 field numbers. The Ellenberger themselves wrote in 1956: "The second [fieldwork], in February 1956, increased this number to almost 700 (which should represent more than 450 complete and distinct bones), […]" (Ellenberger and Ellenberger, 1956b: 100).In 1970, Paul Ellenberger returned for good to France, and continued his work on Lesotho fossils in Montpellier (Southern France). The same year, he wrote a review about Lesotho stratigraphy, in which appear all the fossils, ichnofossils and deposits he discovered during his expeditions. In this paper appears the first name attributed to the Maphutseng dinosaur, which was, at that time, no longer considered as a specimen of Euskelosaurus. Indeed, P.Ellenberger wrote: "A new type of 'Euskelosauridae', perhaps closer to sauropods: 'The Maphutseng Beast' or 'Thotobolosaurus mabeatae' (under study), 1150 bones extracted with