This is the accepted version of the journal article: Vila, Bernat. «Walter Georg Kühne (1911-1991) and the discovery of the first semi-articulated titanosaurian sauropod from Europe». Historical biology, (July 2022). DOI 10.1080/08912963.2022.2100771 This version is available at https://ddd.uab.cat/record/264384 under the terms of the license 1 WALTER GEORG KÜHNE (1911-1991) AND THE DISCOVERY OF THE 2 FIRST SEMI-ARTICULATED TITANOSAURIAN SAUROPOD FROM 3 EUROPE 4 5 Bernat Vila1,2 1 6 Institut Català de Paleontologia Miquel Crusafont, Universitat Autònoma de 7 Barcelona, Carrer Escola Industrial 23, 08201 Sabadell (Barcelona), Catalonia, Spain. 8 bernat.vila@icp.cat 2 9 Museu de la Conca Dellà, Carrer del Museu, 4, Isona (Lleida), Catalonia, Spain. 10 ORCID ID: 0000-0002-5935-1732 11 12 [Word count: 9386 words] 13 14 Abstract 15 In 1954 Walter Georg Kühne (1911-1991), the renowned discoverer of Mesozoic 16 mammals, explored the south-Pyrenean basins of Catalonia with the aim of finding 17 Cretaceous mammal-bearing sites. As a result, the German paleontologist discovered one 18 of the most important dinosaur fossils in the history of dinosaur research in Spain. In the 19 Tremp Basin, near Orcau village, he found the remains of a large sauropod dinosaur, but 20 a series of incomprehensible vicissitudes made the find forgotten and its extraction 21 incomplete for over 60 years. Unprecedented research into the history of this discovery, 22 including unpublished documents, images, and field notes, has revealed details on the 23 costs of the campaigns, the daily logistics, the field techniques, and the fossils unearthed 24 in the 1954 and 1955 excavations. More importantly, this new research ascertains that 25 Kühne had already determined that the dinosaur skeleton was articulated from the pelvic 1 girdle onwards. Even without being published, that was a historically significant 2 achievement as, back then, the new specimen became the first and semi-articulated 3 titanosaurian sauropod found in Europe. Currently, the sauropod fossils found by Kühne 4 in Orcau, together with additional appendicular and axial bones, are the holotype of 5 Abditosaurus kuehnei (Vila et al., 2022). 6 7 Key words: Dinosaur, Walter Georg Kühne, discovery, titanosaurs, Abditosaurus 8 9 Introduction 10 Walter Georg Kühne (1911–1991), also known as the ‘legendary explorer of Mesozoic 11 mammals’ (Kielan-Jaworowska et al., 2004), was one of the leading paleontologists in 12 the study of fossil mammals during the 20th century (Figure 1). Kühne, Professor of 13 Paleontology at Freie Universität Berlin since 1963, authored more than 70 publications 14 (Schlüter, unpublished; Şengör, 2021) that became a cornerstone in the study of 15 Mesozoic mammals (Kielan-Jaworowska et al., 2004; Kielan-Jaworowska, 2013). 16 Notable examples of such papers include the establishment of the genus Morganucodon 17 (Kühne, 1949) and the monograph on Oligokyphus (Kühne, 1956). Besides researching 18 the evolution of early mammals, Kühne also devoted time to other taxonomic groups 19 (the enigmatic lobopodian Xenusion or the Silurian graptolites; Kühne, 1936, 1953), and 20 to illustrate and develop techniques and methods for discovering, collecting, and 21 preparing microvertebrate fossils (Kühne, 1961, 1971). 22 23
24 1 Despite his prolific and extensive academic and fieldwork background, very few people 2 have been aware that Kühne discovered, excavated, and collected the bones of a large 3 dinosaur in Catalonia, representing a very significant discovery in the history of 4 dinosaur research in southern Europe. Although acknowledged to have produced some 5 of the first dinosaur finds in Spain, Kühne's surveys in the southern Pyrenees were 6 reported only in abstracts or short articles in journals of this country (Talens, 1955a, b; 7 Lapparent and Aguirre, 1956a, b; Lapparent, 1958; Bataller, 1958). Internationally, the 8 scientific impact and the relevance of his discovery were non-existent (Weishampel et 9 al., 2004) and, out of Spain, only two articles (Schlüter, 1981; Kohring and Schlüter, 10 1995) made a very short reference to the dinosaur discovered by Kühne in the Upper 11 Cretaceous of Catalonia. Regarding the precise whereabouts of the fossils extracted by 12 Kühne in the 1950s, they remained completely unknown and unstudied for nearly 60 13 years, and only in the last decade some authors reviewed some of the sites (Pereda- 14 Suberbiola and Ruiz-Omeñaca, 2012) and identified a few of the extracted pieces 15 (Martín et al., 2017; Vila et al., 2022). However, no detailed information was available 16 on when and which dinosaur elements Kühne had discovered and extracted, or what 17 interpretations he made during his fieldwork. 18 The aim of this paper is to comprehensively narrate the story of how Kühne discovered 19 the first semi-articulated sauropod dinosaur in the Upper Cretaceous of Europe, as well 20 as to underscore his meritorious paleontological work during his stay in Catalonia. The 21 historical and documentary research carried out in the last decade allows us to expose 22 for the first time the unpublished data of the finding, the excavation and extraction 23 techniques used, and the conclusions reached by the German paleontologist on the basis 24 of fossils that more than 60 years later gave rise to the new titanosaur species 25 Abditosaurus kuehnei (Vila et al., 2022). 1 2 Materials and methods 3 The historical research here presented is largely based on unpublished field notes by 4 Walter Georg Kühne (property of Urs and Anna Klebe), the regular mail 5 correspondence (letters and reports, Appendix 1) of the Lucas Mallada collection 6 housed in the Archivo MNCN-CSIC (Madrid, Spain), some personal letters housed at 7 the Universitäts Bibliothek Freiburg, and the interviews with Eugeni Nadal (Josep 8 Nadal’s son, collaborator in 1954’s Kühne field campaign), and Professor Emiliano 9 Aguirre and Josep Montané (collaborators in 1955’s Kühne field campaign). 10 11 Geological context 12 In Catalonia, Kühne searched for new vertebrate localities in the uppermost Cretaceous 13 continental deposits of the Tremp basin (eastern Tremp syncline, Lleida province) and 14 the region North of Berga (Vallcebre syncline and surrounding areas, Barcelona 15 province) (Figure 2). The continental deposits in these areas correspond to the Tremp 16 Group (Mey et al., 1968) or ‘Garumnian’ facies (see Rosell et al., 2001 for 17 equivalences), a unit deposited atop the Campanian-Maastrichtian Arén Sandstone Fm 18 in the Tremp basin and atop of the Les Serres Limestone Fm (Souquet, 1967) North of 19 Berga. The Tremp group is divided into different formations that encompass the 20 Cretaceous-Paleogene transition. These are the La Posa Fm (grey marls and sandstones, 21 limestones, and coals with abundant invertebrate fauna), the Conques and Talarn 22 formations (an alternation of brown, ochre, and reddish marls with sandstones), the 23 Suterranya and Sant Salvador de Toló Fm (micritic limestones), and the Esplugafreda 24 and Claret formations (red mudstones, sandstones, and conglomerates). Kühne 25 preferently visited the Cretaceous units of the La Posa Fm, to a lesser degree the 1 Conques Fm, and exceptionally outcrops of the Talarn Fm, which all have a 2 Maastrichtian age (Fondevilla et al., 2019) at the areas surveyed. 3 4 Results 5 First field survey in Catalonia and the Instituto Lucas Mallada 6 The story of the discovery of the “Kühne’s dinosaur” began in 1953 when he first 7 traveled to Catalonia. A year before, he had returned to Germany from the United 8 Kingdom, where he had moved in 1938 in search of new opportunities, and where he 9 had succeeded on his search for Mesozoic mammals (such as with the discovery of 10 several individuals of the cynodont Oligokyphus; Kühne, 1956). In 1952 Kühne had 11 become a lecturer of paleontology at the Freie Universität in West Berlin and, as 12 narrated by Schlüter (1981), he had ‘the intention of making an entirely new beginning’. 13 Most likely, this new research approach included the search for fossil mammals in 14 Portugal and Spain, after the option of doing fieldwork in southern China was rejected 15 (Schlüter and Kohring, 1993). Therefore, in October 1953, Kühne moved to Catalonia 16 on his own and started the field survey in the Montsec Range, in NE Spain. There, he 17 visited the quarries of the Lower Cretaceous konservat-lagerstätte of La Pedrera de 18 Rúbies and later moved northwards to the Tremp basin, where he prospected the 19 Cretaceous outcrops around the Vilamitjana, Suterranya, and Llordà villages (Figure 20 2A). That was his first contact with the continental ‘Garumnian’ facies of the south- 21 Pyrenean basins. 22 23
24 1 In January 1954, after that first field survey in Catalonia, Kühne wrote a letter to 2 Bermudo Meléndez, paleontologist and secretary of the Instituto Lucas Mallada (now 3 included in the Museo Nacional de Ciencias Naturales) in Madrid, expressing his 4 interest in conducting research on coal mines in the southern Pyrenees. He also 5 explained the finding of ‘isolated bones of an amphibian in the ‘Garumnian’ coal mines 6 in Suterranya’ (letter 17/01/1954, can0773). Three months later, in a second letter, he 7 formally presented a plan to the Instituto Lucas Mallada for systematic surveys and 8 excavations in the summer of the same year (letter 20/04/1954, ACN0773). Kühne 9 explained that assemblages of vertebrate fossils occur frequently in the Tertiary coals of 10 Eastern Europe and insisted that the numerous Cretaceous coal deposits that had been 11 discovered in Spain needed to be explored. Kühne justified this by the fact that after his 12 explorations of the Cretaceous coals of Suterranya (Tremp Basin) in the previous year 13 he had collected a jaw with teeth that he had attributed to a lacertid. Therefore, that 14 finding was ‘clear material evidence that, as in the Tertiary coals, vertebrates exist in 15 Cretaceous coals’ (letter 20/04/1954, ACN0773). Thus, according to the Berliner 16 paleontologist, ‘the only way to determine whether vertebrate fossils exist in the 17 Spanish Cretaceous coals is through systematic study and exploration’, and therefore he 18 proposed to prospect in the coal mines of the Pyrenees from August to October of 1954. 19 In the same letter, Kühne made it very clear that his goal was ‘the discovery of 20 Cretaceous mammals’ and set out his working conditions, which included, among other 21 things, the possible hiring of mine personnel during this work. 22 The Instituto Lucas Mallada evaluated the proposal and two months later, on the 28th of 23 June of the same year, Professor Bermudo Meléndez informed Kühne that the Standing 24 Committee of the Instituto Lucas Mallada had approved the plan and a budget of 12,000 25 pesetas (the equivalent of 2800€ in today’s currency) to carry out the work (Figure 3) 1 2
3 4 Fieldwork in northern Berga and the Josep Nadal’s find 5 With the approved budget, Kühne began prospecting on the 29th of August 1954, in the 6 ‘Garumnian’ outcrops of northern Berga (north of Barcelona, Catalonia). He 7 specifically visited the dumps and the surrounding outcrops of most of the active coal 8 (lignite) mines in the vicinities of the Fígols, Vallcebre, Sant Salvador de la Vedella, 9 Cercs, La Nou de Berguedà, Saldes, and La Pobla de Lillet villages (Figure 2B). Kühne 10 mainly prospected the ‘Grey garumnian’ (including outcrops of the ‘lower limestones 11 with coals’ and ‘marls with coals’ units; Aepler, 1967; Oms et al., 2007) and identified 12 some beds with abundant ostracods, gastropods, and other mollusks (e.g., Unio), and 13 plant remains (Talens, 1955a). Regarding dinosaurs and other vertebrates, he only 14 mentioned on his field notes a small limb bone shaft (30cm in length; 4x7cm in cross 15 section) collected in Mina Consolació (Fígols), a small piece of turtle shell from Mina 16 Campos (Saldes) from a private collection, and ganoid fish scales from Mina Tumí 17 (Vallcebre). Some years later, those early surveys became the basis for the Diploma- 18 thesis (equivalent of Master) of Reinhardt Aepler from Freie Universität Berlin (Aepler, 19 1967). 20 In the 20th of September 1954, Kühne focused his efforts on the Tremp basin (Figure 21 2A), around Suterranya village and other outcrops near Vilamitjana, Gavet de la Conca, 22 Basturs, Orcau, and Figuerola d’Orcau, where he collected some vertebrate bone 23 fragments. During the weeks he surveyed the area, Kühne stayed in Suterranya and 24 asked the people of the village about the presence of fossils collected or identified in the 25 area. On the 23rd of September, he ‘took a piece of bone and showed it to all the farmers 1 working in the field and asked them if anybody had seen anything like it before. The 2 third person who was then approached answered my question affirmatively’ 3 (transcribed and translated from German; Kohring and Schlüter, 1995). That person, 4 Josep Nadal Miró (1906-1992), explained that at some point between 1950 and 1952 he 5 had collected a fossil bone while hunting ‘in a ravine halfway between Suterranya and 6 Orcau’ (Kühne field notes). Nadal thought it was a mammoth bone (Eugeni Nadal, 7 personal communication 2015), but the German paleontologist immediately identified it 8 as a dinosaur bone, specifically as the distal end of a metapodial [‘… the farmer showed 9 me half a well-preserved metatarsal bone of a medium-sized dinosaur’] (translated from 10 German; Kohring and Schlüter, 1995). Kühne underscored that ‘It had a dark brown 11 color, distinctly different from the gray-blue color of the bones identified in the eastern 12 Suterranya’ (Kühne field notes). It was the first clear indication of the presence of 13 dinosaur bones in the area (Figure 4A and B). 14 At the end of the summer of 1954, Kühne visited the Instituto Lucas Mallada and 15 handed the bone over to Bermudo Meléndez. On November, Meléndez wrote to Josep 16 Nadal thanking the help given to Professor Kühne and stating that he would be paid 250 17 pesetas for the bone (Figure 4C). The specimen was deposited at the Museo Nacional de 18 Ciencias Naturales de Madrid (specimen no. MNCN59304) but it was not studied by 19 anyone, not even by Kühne, until about 60 years later when Escaso et al. (2010) and 20 Martín et al. (2017) referred it to a humerus of Nodosauridae indeterminate. 21 Interestingly, the present search reveals for the first time that indeed the place where 22 Nadal found the bone was somewhere in the ravine that runs from east of Suterranya to 23 Orcau (Barranc dels Cantals), and therefore in Lower Maastrichtian outcrops of the La 24 Posa or the Conques formations (‘Grey Garumnian’ or ‘Lower Red Garumnian’, 25 respectively) (Fondevilla et al., 2019), but it does not correspond to the ‘Locality 4’ of 1 Lapparent and Aguirre (1956b) also named ‘Suterranya-Mina de lignit’ (contra Sellés 2 and Vila, 2015 and Martín et al., 2017). 3 4
5 6 Discovery and first excavation (1954) 7 After Nadal’s finding, on the 25th of September they both visited the outcrops between 8 Orcau and Suterranya. ‘The next morning the farmer took me to the place where he had 9 collected the piece. It was a 500 m wide erosive ravine with more than 20 gullies. I 10 started my search for the westernmost gully and I found the dinosaur skeleton at the 11 easternmost’ (translated from German; Kohring and Schlüter, 1995). Kühne determined 12 that the bone fragments, some of considerable size, belonged to dinosaurs and he was 13 therefore convinced that it was a place worth excavating. Over the next two days he 14 prepared the excavation and continued prospecting east of Orcau, and north of Basturs 15 (points 19 and 20, Figure 2A). 16 On the 28th of September, the excavation started and nine days later he had already 17 identified about ten bones. Some of them (two chevrons, a right tibia, and the distal half 18 of a left femur) were collected (Table 1). Additional six complete or partial bones (a 19 complete left humerus, the proximal half of a left femur, a ‘large and flat bone’, two 20 articulated dorsal vertebrae, the distal half of a left fibula) were protected with jackets 21 and left at the site. During the excavation days, Kühne wrote important notes on 22 excavation and extraction techniques in his field notebook, as it was an unprecedented 23 excavation with a large skeleton in a remote place. The excavation and extraction of the 24 bones proved difficult for Kühne because the bones were embedded in a marl layer with 25 a strong dip. Therefore, he accompanied the sketch in Figure 5 with a note in which he 1 stated that ‘Future excavation must take place in a cut whose excavation surface falls 2 into the mountain. Only in this way it can be prevented that when a bone is exposed, 3 another bone falls over it, so that in ‘normal excavation’ the excavation surface is 4 covered with imbricating bone ends and no progress is possible.’ (transcribed and 5 translated from Kühne field notes). 6 7 8 9
10 11 The excavation ended on the 6th of October and, after a day of preparing the jackets to 12 safely remove the bones, Kühne and Nadal spent another day transporting them to 13 Nadal’s house in Suterranya. There, before returning to Germany, Kühne asked his 14 colleague to send them to the Instituo Lucas Mallada in the next weeks. Nadal 15 distributed the jackets into four wood boxes and on the 13th of December he registered 16 them to Madrid from the Tremp railway station. By the beginning of January 1955 all 17 the four boxes containing the dinosaur fossils arrived in Madrid in perfect condition. 18 Almost at the same time, Kühne send a field report to Professor Maximino San Miguel 19 de la Cámara, director of the Instituto Lucas Mallada, in which he detailed all the 20 fieldwork activities and the main conclusions after prospecting for and the excavating of 21 the fossil materials. Most significant was the fact that the fossil accumulation was more 22 extensive, that a second excavation was needed to determine whether the skeleton was 23 complete, and that the remains could be assigned to a large sauropod dinosaur of the 24 family Titanosauridae (letter and report 10/01/1955, ACN0738). Based on his report, 25 Jacinto Talens summarized the fieldwork and referred the material tentatively to the 1 genus Titanosaurus (Talens, 1955a), now considered as a nomen dubium (Wilson and 2 Upchurch, 2003). 3 4 Once back in Germany and after the unexpected discovery of dinosaurs near Orcau, 5 Kühne wrote to Professor Otto Heinrich Schindewolf (1896-1971): ‘In Spain I 6 “encountered” a titanosaurid from the Upper Cretaceous and brought some specimens to 7 Madrid, the unearthed huge rest is waiting for me until the summer of 1955. Thus, you 8 go out to find rat-sized Cretaceous mammals (‘Ratten-große’, sic) and bring home a 10- 9 ton beast, and that's just the beginning’ (translated from German, letter to Professor 10 Schindewolf, December 1954). 11 12 Second excavation (1955) 13 With the final report on January 1955, Kühne also submitted a new proposal to the 14 director of the Instituto Lucas Mallada (letter 10/01/1955, ACN0738). This included a 15 new working plan for that year to carry on the excavation of the sauropod skeleton in 16 Orcau and the prospects in the Tremp basin. The proposal included three months of 17 fieldwork and asked for professional fees of 550 German marks, the travel expenses of 18 the round trip from Berlin, the daily subsistence allowances, and an extra fund of 9,000 19 pesetas. Finally, he requested the material costs (plaster, boxes, packaging, and 20 transport) and the hiring of two workers for a month who assisted in removing sediment 21 from the site. Bermudo Meléndez replied that the Instituto Lucas Mallada accepted his 22 plan for the excavation of the sauropod's skeleton, but informed Kühne that the institute 23 would appoint a Spanish paleontologist to accompany him and take charge of the fossils 24 (letters 9, 11/05/1955, ACN0738). The person assigned to accompany Kühne was 1 Emiliano Aguirre (1925-2021), at that time a 30-year-old fellow from the Instituto with 2 a degree in Natural Sciences (letter 15/08/1955, ACN0738). 3 In early July, the Instituto Lucas Mallada officially notified Kühne that it would 4 subsidize his proposal with 12,000 pesetas (the same amount as the previous year) and 5 that they would take care of the remaining expenses, including the daily wage of the 6 worker, the material, and the transportation of the fossils to Madrid (letter 07/07/1955, 7 ACN0738). 8 With all the funding available and the permissions ready, Kühne started the second 9 excavation in the Orcau site. Emiliano Aguirre arrived in Tremp on the 14th of August 10 and joined the excavation from the beginning, on the 16th of August, being mainly 11 responsible for documenting the progress of the work with photographs and notes. 12 On the afternoon of the 17th of August, Kühne and Aguirre headed for the pathway from 13 Suterranya to the ravine where the fossils had appeared the previous year (a ravine now 14 called ‘Barranc dels Cantals’, Figure 6A and B). The German and the Spanish 15 paleontologists entered the ravine from its lowest and westernmost stretch (Figure 6C) 16 and after walking along the riverbed about 500 meters to the east they arrived at the 17 sauropod site (Figures 6D and E) and evaluated it after a year of inactivity. The 18 excavation formally began six days later, on the afternoon of the 23rd of August, when 19 the two paleontologists removed the surface debris to rediscover the six pieces that 20 Kühne had left protected the previous summer. 21 22
23 24 As Kühne had pointed out the year before, the excavation could not be carried out 25 without further digging into the excavation front as this would be covered with 1 sediment and the bones would not be identified. The aim was to remove vertically the 2 southern edge of the gully in order to have more workspace available, and to crop out 3 the layer with bones in the deepest point of the hollow, which plunged strongly to the 4 south. At the same time, it was necessary to lower the northern edge of the gully along 5 the entire width of the excavation front, about 4-5 meters in an east-west direction, in 6 order to make the layer with bones visible on the surface. 7 To carry out this work, Josep Montané Morera, a 21-year-old miner from Suterranya 8 and the person who was finally hired by the Instituto Lucas Mallada to work as a 9 stonecutter, joined the team at the second day. The three expedition members lowered 10 the gully's margins with picks, shovels, and pickaxes, but it soon became clear that 11 more expeditious methods had to be used. 12 The next morning Aguirre went to Tremp to acquire explosives, while Kühne and 13 Montané continued to manually lower the gully's head and its southern and northern 14 margins. By the end of the day, the depth of the excavation front inside the gully had 15 been reduced by 80 cm (Figure 7A). 16 On the morning of the 26th, two explosives’ technicians from the Suterranya mine, Pere 17 Fàbregas and Frederic Vergés, visited the site and exploded several shot holes with 18 dynamite (Figure 7B and C). 19
20 21 Then they all began the work of cleaning the hollow and the surface of the excavation 22 front, removing the excess debris (Figure 7D). This process was repeated for the next 23 two working days until they had cut out a space 3 meters deep, 6 meters wide and 2.5 24 meters length (Figure 8A) with the bone-bearing layer located on the northern edge of 25 the hollow and dipping south (Figure 8B). At the end of this work, on the 31st of 1 August, the first bone appeared (a femur of about 120-130 cm long; Figure 8C) and 2 Kühne began to delimite it. 3 4
5 6 The very same day, Aguirre left the excavation, and from that moment on, Kühne and 7 Montané were the only members of the expedition in charge of discovering and 8 delimiting new bones and extracting and covering them with jackets. On the 1st of 9 September, Kühne began a general mapping of the accumulation of bones (Figure 9A) 10 with sketches of the relative position of the elements and numbered the bones indicating 11 the year and a correlative numbering (e.g., 55/1, 55/2, 55/3, etc.). He also noted features 12 on their preservation. For instance, he documented that ‘except for the shafts of the 13 appendicular bones, most of the bones are pierced by ‘worm’ traces in all directions (not 14 observed in the 3 chevrons). The preservation - with the exception of the largest bones - 15 is poor.’ (transcribed and translated from German, Kühne field notes). 16 Preparing the bones to be safely extracted was a complex task, especially the vertebrae. 17 Kühne annotated in his field notebook that ‘he had worked unsuccessfully on the 18 vertebral mess (‘Wirbelschweinerei’)’ or that ‘at the end of the day I left this hideous 19 preparation!’ (transcribed and translated from German, Kühne field notes). In fact, he 20 could not recover the three articulated dorsal vertebrae (55/6; Figure 9B) and left them 21 on the site. Plate bones such as the scapula were also very difficult to consolidate and 22 extract entirely. This was also the case for the probable ilium (55/10) and perhaps other 23 bones of the pelvic girdle, which appeared fragmented in several parts and with other 24 bones (e.g., ribs) attached on top (Figures 9C and D). Due to these circumstances, 25 Kühne stated that ‘several small parts of this object were extracted (55/10), but most of 1 them are still in the field’ (report 23/02/195, ACN0739). When bones were attached one 2 to each other or were closely articulated he also had problems to safely preserve them. 3 Thus, he admitted that ‘In the recovery of 55/5 [left humerus], the western corner of 4 55/7 [glenoid of left scapula or coracoid] was destroyed before its girdle nature was 5 recognised’, (transcribed and translated from German, Kühne field notes). When 6 possible, Kühne glued bony fragments and consolidated parts of the bones with flour 7 glue and prepared jackets with plaster, jute, and paper (usually newspaper sheets). 8 Altogether, Kühne collected and/or mapped about ten sauropod bones (a complete right 9 femur and humerus, the distal half of a left fibula, the anterior end of a left scapula, a 10 chevron, an indeterminate ‘short’ bone, a few small fragments of an ilium, a complete 11 dorsal vertebra, and fragments of at least three dorsal ribs) together with almost all the 12 bones left in the previous campaign (except for the dorsal vertebrae and other 13 indeterminate bones). In addition, Kühne reported ‘an isolated crocodile tooth’ 14 (transcribed and translated from German, Kühne field notes). As in 1954, Kühne left 15 small parts of mapped bones (most of the ilium fragments, 55/10; two dorsal ribs, 55/11 16 and 12; the posterior blade fragment of the left scapula, 55/9; and three articulated 17 middle dorsal vertebrae; Figure 9B, C) at the site, protected under plaster. The 18 maximum depth of the digged hole at the end of excavation was 3m, reached in the 19 middle of the excavation at a length of 2m. 20 21
22 23 Another important difficulty of the excavation was the access to the site, and thus, the 24 transportation of the bones to the nearest village, Suterranya, represented a real 25 challenge to Kühne and his colleagues. In the first week of work at the site, Emiliano 1 Aguirre remarked that the long trail following the ravine ‘is inaccessible by the mules. 2 The pieces must be carried on the shoulder to the ravine entrance (Figure 6C). From 3 there to the town, [there is] a bad pathway to go on foot and mule.’. So, in the last days 4 of excavation, when Kühne and Montané had to extract and transport the bones out of 5 the site, they ruled out to carry the bones along the riverbed. Therefore, they devised a 6 particular system of transport more suitable to the particular terrain conditions. First, 7 Kühne and Montané put the jacket (20-30kg) they had to carry into a sack full of straw; 8 next, they tied the sack with a 10-meter rope that they dragged down the slope to the 9 riverbed. Once there, the sack was tied to a pole and transported by the two men, who 10 climbed as far as possible to the other side of the ravine. Then, the bag was put back on 11 the rope and dragged up again to a flat area on top of the hill where it was tightly stuffed 12 with more straw and transported by mule to Suterranya. The excavation ended with the 13 last pieces being transported on the 22nd of September (report 23/02/1956, ACN0739). 14 Similarly to what Nadal had made the previous year, Montané stored the jackets in his 15 house, and four days later he distributed them onto nine boxes and registered them to 16 Madrid from Tremp (letter 28/09/1955, ACN0738). 17 18 New attempts for more excavations 19 In February 1956, Kühne sent a report on the excavation conducted the previous 20 summer and asked the Instituto Lucas Mallada to undertake an additional excavation 21 (letter 22, 23/02/1956, ACN0739). In April, the director of Instituto and Bermudo 22 Meléndez responded by expressing great satisfaction with the work done and, although 23 Meléndez could not anticipate the conditions for the excavations and did not yet have a 24 detailed work plan, they conveyed the confidence of continuing the excavations in the 25 summer 1956 (letter 13/04/1956, ACN0739). Meléndez also informed Kühne of an 1 agreement that the Instituto Lucas Mallada had reached with Abbé Albert-Félix de 2 Lapparent, ‘one of the few dinosaur specialists in Europe’. The agreement was ‘for him 3 to be in charge, once the extraction of remains is finished, of his study and assembly in 4 the Museo of Madrid with the collaboration of Emiliano Aguirre’. Thus, the provisional 5 plan was that the 1956 excavation would be carried out by Kühne and Aguirre with 6 some visits of Lapparent (letter 13/04/1956, ACN0739). 7 Indeed, two months later (on the 21st of June), the Instituto Lucas Mallada sent a letter 8 to the president of its board to explain that 9 ‘Professor Lapparent will come to Spain next summer and will be in Madrid to 10 visit the site and study the collected fossils. Apart from the round-trip travel expenses 11 from Paris, the accommodation expenses of the said Professor in Spain can be 12 calculated at about ten thousand pesetas’ (the equivalent of 2,300€ in today’s currency; 13 translated from Spanish, letter 21/06/1956, ACN0739). 14 Four days later, however, Meléndez informed Kühne that they had to cancel the 15 excavations in Tremp because the Consejo Superior de Investigaciones Científicas had 16 denied ‘the credit that in previous years has been granted to this institute [the Instituto 17 Lucas Mallada] for research carried out by foreign professors’ (letter 25/06/1956, 18 ACN0739). Thus, it seems that the Instituto Lucas Mallada did not obtain the funds to 19 subsidize Kühne’s planned work on the Orcau excavation but maintained a commitment 20 for inviting and funding Lapparent to study the material already deposited in Madrid 21 and conduct a new exploration in the Tremp basin. In this context, in the summer of 22 1956, Albert-Félix de Lapparent and Emiliano Aguirre visited the Tremp basin and 23 explored the main ‘Garumnian’ outcrops (Lapparent and Aguirre, 1956a, b). Kühne no 24 longer excavated the Orcau locality and neither Lapparent nor Aguirre extracted more 25 bones from there. Regarding the study of the remains of the sauropod deposited in the 1 Museo Nacional de Ciencias Naturales, it seems that Lapparent had never studied them 2 in detail as they remained in jackets until the 80s and early 2000s. However, Lapparent 3 and Aguirre (1956a) referred part of the collected material to a new species of 4 Hypselosaurus that is currently considered a nomen dubium (Le Loeuff, 1993). 5 6 Other significant findings of Kühne 7 The first week of the 1955 survey, before starting the excavation in Orcau-1, Kühne and 8 Aguirre prospected together the 'Garumnian' outcrops of the Tremp Basin, except for 9 three days (19th to 22nd of August) in which Kühne prospected on his own. On the 19th 10 and 20th of August the German paleontologist visited various outcrops from 11 northeastern Basturs, the Barranc de la Costa Gran and later the western gullies of 12 Barranc de Basturs (Fig. 10A). The descriptions made by Kühne in his field notes 13 during those days refer to unusual fossils. Thus, in the western gullies of Barranc de 14 Basturs he found no bones but ‘flat hand-sized snail and 15-20cm diameter ‘grey’ 15 calcite-covered sphaeres’ (flache handgroße Schnecke und 15-20 cm Durchnesser graue 16 Calzit bedeckte Sphaeren, transcribed and translated from Kühne field notes). 17 At present one knows that the ‘flat hand-sized snail’ most probably corresponds to the 18 Lychnus gastropod, the only gastropod of this size reported in the egg-bearing levels of 19 the Barranc de Basturs and Barranc de la Costa Gran outcrops (Lapparent, 1958; Sanz et 20 al., 1995; Sander et al., 1998), atop of the Aren Sandstone Fm. Alongside the Lychnus 21 gastropod, the “15-20cm diameter ‘grey’ calcite-covered sphaeres’ reported in this 22 stratigraphic level probably might be interpreted as dinosaur (megaloolithid) eggs (Fig. 23 10B). Due to its size and composition, they might be alternatively interpretated as 24 oncolites; however, this interpretation can be ruled out as no oncolite-bearing levels 25 have been reported in none of these two ravines prospected by Kühne. 1 Therefore, I interpret the descriptions of these unusual fossils reported by Kühne as 2 those of likely dinosaur eggs. More specifically, they might correspond to the eggs 3 described three years later, in September 1958, by Albert F. de Lapparent, C. Bézier, 4 and N. Glachant in the Basturs eggsites (Lapparent, 1958). That both scientists referred 5 to the same localities is proved by a citation of the French paleontologist about Kühne's 6 visit at the locality three years before (‘W. Kühne avait déjà reconnus à cette place en 7 1955’; Lapparent, 1958). Despite having misidentified the fossils (probably due to his 8 lack of expertise or to the fact that they were extremely unknown and rare at that time), 9 I argue that Kühne could have been the original discoverer of the dinosaur eggs in the 10 Basturs site in August 1955. However, the formal interpretation of these remains 11 corresponds to the publication of Albert-Félix de Lapparent in 1958. 12 13
14 15 Discussion 16 The most commendable milestone of Kühne’s finding in the Orcau-1 locality is the fact 17 that by the end of the 1955 season he gathered evidence that led him to conclude that 18 the sauropod was articulated from the pelvic girdle onwards, with the body axis oriented 19 north-south, and preserving the neck and the skull (Figure 11A). Therefore, on his field 20 notes he argued: 21 ‘Signs that neck and head are south of the shoulder region: 22 1) One dorsal spine of the three associated vertebrae is northward directed 23 2) The northernmost element is a caudal chevron 24 3) No more than 6 limb bones have been found to date.’ 25 and 1 ‘…many of these [vertebrae], however, [are] in the centre’. 2 In this passage, Kühne probably referred to that they were trunk or dorsal vertebrae, as 3 an indication of their position along the sauropod body length. 4 ‘[there is a] …large cluster of bones in an area of unknown length and about 5 1.5m wide.’ and ‘West of excavation all outcrops thoroughly searched without 6 success, only one loose limb fragment’ 7 Here, he probably underscored the fact that most of bones accumulated in a small area 8 and were in contact one to each other, not dispersed, as a clear signal of authoctony and 9 low transportation. 10 Finally, Kühne concluded that ‘The body axis most probably is in a north-south 11 direction’. 12 13 A review of the bone distribution in the Orcau’s quarry map resulted in additional 14 evidence to support Kühne’s interpretation. First, the main appendicular bones (femora 15 and humeri) appeared symmetrically positioned on both sides (right and left) of the 16 accumulation. Second, some of these bones, specifically the left elements, were found 17 articulated with the corresponding girdles (i.e., the left femur was found articulated with 18 the acetabulum of the left ilium and the left humeri appeared articulated with glenoid 19 area of the left scapula; Fig. 11B). This distribution indicates an authoctonous 20 accumulation of the elements affected by very low transportation and a rapid burial of 21 the sauropod carcass that favored the semi-articulation of the skeletal elements. 22 23
24 Unfortunately, the Instituto Lucas Mallada did not put faith in continuing the extraction 25 of the dinosaur and therefore Kühne’s assumptions could not be confirmed until 60 1 years later (Vila et al., 2022). However, the present literature review denotes how 2 relevant was Kühne’s prediction, as in 1955 there was only one sauropod species 3 described in Europe on the basis of articulated or semi-articulated skeletons (the current 4 nomen dubium ‘Macrurosaurus semnus’ Seeley 1876). Thus, almost all species of 5 sauropods from all ages (Middle Jurassic to the Upper Cretaceous) known in Europe 6 before 1955 had been described from isolated, fragmentary, or disarticulated remains. 7 Therefore, the Orcau sauropod became at that time the second semi-articulated 8 sauropod found in Europe, despite having been only partially collected in 1955. Among 9 titanosaurs, the first species had been described in Europe 23 years before 10 (Magyarosaurus dacus, M. hungaricus, and M. transylvanicus from the Maastrichtian 11 of Romania; Huene 1932) from isolated, fragmentary, and disarticulated material. It was 12 not until the middle 2010s that Lohuecotitan pandafilandi (Díez Díaz et al., 2016) and 13 some other unnamed remains (Ortega et al., 2015) from Lo Hueco site in Spain were 14 described and/or reported as semi-articulated skeletons. Thus, the recently defined 15 species from Orcau (Abditosaurus kuehnei, Vila et al., 2022) was described on the basis 16 of the first semi-articulated titanosaurian skeleton found in the Late Cretaceous of 17 Europe. This fact highlights the importance of Kühne’s finding, reasserts the work 18 conducted by him, and emphasizes his paleontological instinct. 19 20 Finally, the discovery of the Orcau sauropod gives evidence of ‘Kühne’s unusual talent 21 for finding fossils’, as Zofia Kielan-Jaworowska had already stated in 2013. 22 Nevertheless, the finding was accidental as Kühne’s original purpose was to find fossils 23 of Cretaceous mammals specifically in the coal mines of the area. The finding, 24 however, did not include mammals at all but a large dinosaur and occurred in non- 25 carbonaceous sediments. This leads us to speculate on how the methodological 1 principles of Kühne (Schlüter, 1981; Şengör, 2021) changed or failed during the field 2 survey in the Tremp basin. Originally, the discovery of vertebrate remains in the 3 Suterranya coal mine in 1953 led him to follow the principle that Schlüter and Kohring 4 (1993) named as the ‘principle of series-formation’, in which the Berliner paleontologist 5 used to link geological phenomena isolated in time and space to determine the likely 6 whereabouts of new fossil-bearing localities (Şengör, 2021). He had already applied this 7 reasoning with the finding of early mammals in karst fissures in England (Kühne, 1947) 8 and subsequently of amber in the Paris and Acquitanian basins (Kühne et al., 1973). 9 That is to say, Kühne aimed to determine the likely occurrence of mammals (or other 10 vertebrates) in the coal beds of the South-Pyrenean region based on the evidence from 11 the fossil-bearing localities of the Tertiary coal mines of eastern Europe. Therefore, he 12 followed a series of parameters indicative of facies where Tertiary vertebrates 13 eventually occurred to search for fossils in stratigraphically older (Cretaceous) layers. 14 Kühne initially prospected exclusively the coal mines of Suterranya and Llordà in 1953 15 and those from North Berga region in 1954, but with the finding of a dinosaur skeleton 16 away from the carbonaceous facies he expanded the search to other sediments in the 17 later 1954 and 1955 surveys (Figure 2). Thus, in Orcau he most probably did not follow 18 his ‘principle of series-formation’ as he lacked any analogous example for dinosaur 19 bone accumulations in continental deposits. 20 21 Conclusions 22 The Professor Walter Georg Kühne (1911-1991) was one of the most renowned 23 paleontologists in the 20th century, especially for the discovery and description of 24 Mesozoic mammals. In the middle 1950s, he visited the south-Pyrenean basins of 25 Catalonia in the search of new mammal localities following his methodological 1 principles, but against all odds he discovered the remains of a large sauropod dinosaur 2 in the Tremp Basin. Sixty years later, the finding of his field notes, alongside the 3 analysis of unpublished documents and images, and interviews with people that 4 collaborated with him in the field, allows to reconstruct the daily logistics of the 5 campaigns, the field techniques used, and the fossils unearthed. This historical review 6 ascertains that Kühne determined that the dinosaur skeleton was articulated from the 7 pelvic girdle onwards, and thus the new specimen became the first and only semi- 8 articulated titanosaurian sauropod found in Europe. Additionally, the present study 9 concludes that he could have been the discoverer of the famous egg localities of 10 Basturs, in the Tremp basin, three years before Albert Félix de Lapparent reported them. 11 12 Acknowlegments 13 I want to thank the help and collaboration of many people, with particular mention to 14 Josep Montané and Professor Emiliano Aguirre (1925-2021) who excavated alongside 15 Walter G. Kühne. Thomas Schlüter (University of Swaziland), Klaus-J. Reutter (Freie 16 Universität Berlin) and Gerhard Hahn (Berlin and Marburg) provided key information 17 for finding Kühne’s field notes. The children of Kühne, Urs and Anna Klebe, assisted 18 with the transcription and translation of the field notes and gave permission to 19 reproduce images from them. Thomas Schlüter, Rolf Kohring, and Urs Klebe provided 20 bibliographic references. Michael Schudack, Rolf Kohring, Jens Kosch (Freie 21 Universität Berlin), Gabriele Kaiser (Staatsbibliothek zu Berlin), Doris Schweizer 22 (Universitäts Bibliothek Freiburg), Nikolas Malchus, Laila Pilgren, (Institut Català de 23 Paleontologia Miquel Crusafont), and Rodrigo Gaete (Museu de la Conca Dellà) 24 assisted in the documents search. Eugeni Nadal provided information on his father’s 25 find. The Archivo Museo Nacional de Ciencias Naturales-CSIC provided permissions 1 to study and reproduce images and documents. I thank Adán Gregorio, Mònica Vergés, 2 and María del Pilar Rodríguez Luque for let me access the documents. Adán Pérez 3 (UNED) provided some images. Albert Prieto-Márquez reviewed the English. An early 4 version of this manuscript was improved with the comments of Thomas Schlüter, 5 A.M.C. Şengör, and an anonymous reviewer. 6 This research is part of the project VEBPI (reference I+D+i/PID2020-119811GB-I00) 7 funded by MCIN/AEI/10.13039/501100011033/ and the project PLEC2021-007903 8 funded by MCIN/AEI/10.13039/501100011033 and ‘NextGenerationEU’/PRTR. 9 Additional funding was provided by the CERCA Programme and the project 10 CLT009/18/00067 funded by the Departament de Cultura of the Generalitat de 11 Catalunya. 12 13 Disclosure statement 14 The author declares no potential conflict of interest. 15 16 References 17 Aepler R. 1967. Das Garumnian der Mulde von Vallcebre und ihre Tektonik (Spanien, 18 Provinz Barcelona). [The Garumnian of the Vallcebre basin and its tectonics]. 19 [Master thesis]. Berlin: Freie Universität Berlin (Naturwissenschaftlichen Fakultät). 20 German. 21 Ardèvol L, Casanovas ML, Santafé JV. 1995. 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Soc. 32: 25 440–444. 1 Sellés AG, Vila B. 2015. Re-evaluation of the age of some dinosaur localities from the 2 southern Pyrenees by means of megaloolithid oospecies. J. Iber. Geol. 41(1): 125– 3 139. 4 Şengör, A.M.C. 2021. An outstanding scientist, a great book and an infernal title. Int J 5 Earth Sci 110: 759–765. 6 Souquet P. 1967. Le Crétacé supérieur sud-pyrénéen en Catalogne, Aragon et Navarre 7 [The southern Pyrenean Upper Cretaceous in Catalonia, Aragon and Navarre] 8 [dissertation]. Toulouse (France): Université de Toulouse. French. 9 Talens J. 1955a. Descubrimiento de dinosaurios en Tremp (Lleida) [Discovery of 10 dinosaurs in Tremp (Lleida)]. Estud. Geol. 11: 86. Spanish. 11 Talens, J. 1955b. Exploraciones sobre los dinosaurios de la Cuenca de Tremp (Lérida) 12 [Explorations on the dinosaurs of the Tremp Basin (Lérida)]. Estud. Geol. 11: 456. 13 Spanish. 14 Vila B, Sellés A, Moreno-Azanza M, Razzolini NL, Gil-Delgado A, Canudo JI, 15 Galobart À. 2022. A titanosaurian sauropod with Gondwanan affinities in the latest 16 Cretaceous of Europe. Nature Ecology & Evolution DOI: 10.1038/s41559-021- 17 01651-5 18 Weishampel DB, Dodson P, Osmólska H, editors. 2004. The Dinosauria, Second 19 edition. Berkeley (CA): University of California Press. 20 Wilson JA, Upchurch P. 2003. A revision of Titanosaurus Lydekker (Dinosauria – 21 Sauropoda), the first dinosaur genus with a ‘Gondwanan’ distribution. Journal of 22 Systematic Palaeontology 1: 125–160. 23 1 Appendices 2 Appendix 1: Unpublished documents from the Archive MNCN-CSIC (Lucas Mallada 3 collection) 4 5 Collection ACN0773 6 - letter from W.G. Kühne to Professor Meléndez (17/01/1954), 1p. 7 - letter from Professor Meléndez to W.G. Kühne (05/04/1954), 2p. 8 - letter from W.G. Kühne to Professor Meléndez (20/04/1954), 3p. 9 - letter from Professor Meléndez to W.G. Kühne (28/06/1954), 1p. 10 - document of payment approval (26/07/1954), 1p. 11 - letter from Professor Meléndez to Josep Nadal (24/1/1954), 1p. 12 - letter from Josep Nadal to Professor Meléndez (13/12/1954), 1p. 13 Collection ACN0738 14 - letter from W.G. Kühne to the Director of the Instituto Lucas Mallada 15 (10/01/1955), 2pp. 16 - letter (1p) from W.G. Kühne to Prof. M. San Miguel de la Cámara + report 17 (4pp) (10/01/1955). 18 - letter from Prof. Meléndez to W.G. Kühne (09/05/1955), 1p. 19 - letter from Prof. Meléndez to W.G. Kühne (11/05/1955), 1p. 20 - document of payment approval (13/06/1955), 2pp. 21 - letter from Prof. Meléndez to W.G. Kühne (7/07/1955), 1p. 22 - certificate by Bermudo Meléndez (15/08/1955), 1p. 23 - manuscript letter from Emiliano Aguirre to Bermudo Meléndez (16/08/1955), 24 2pp. 25 - field report by Emiliano Aguirre (July-August 1955), 7pp. 1 - manuscript letter from Josep Montané to the Director of the Instituto Lucas 2 Mallada (28/09/1955), 1p. 3 - letter from Bermudo Meléndez to Josep Montané Morera (7/10/1955), 1p. 4 5 Collection ACN0739 6 - letter from W.G. Kühne to Bermudo Meléndez (22/02/1956), 2pp. 7 - letter from W.G. Kühne to Prof. M. San Miguel de la Cámara (22/02/1956), 8 1p. 9 - field report by W.G. Kühne (23/02/1955), 3pp. 10 - letter from Bermudo Meléndez to W.G. Kühne (13/04/1956), 2pp. 11 - letter from W.G. Kühne to Bermudo Meléndez (25/06/1956), 1p. 12 - letter to the President of ‘Patronato ‘Alonso de Herrera’’ (21/06/1956), 1p. 13 1 Figure Captions 2 3 Figure 1. Professor Walter Georg Kühne (1911–1991), during a lecture at the 4 Palaeontological Society of Berlin in 1959 (courtesy of Urs and Anna Klebe). 5 6 Figure 2. Geographic map of Catalonia with indication of the main Upper Cretaceous 7 localities and villages visited by Walter Georg Kühne from 1953 to 1955. A, Tremp 8 basin; B, Northern Berga region. Prospecting areas/localities: 1, ‘around Vilamitjana 9 cemetery’; 2, Mina de Suterranya (i.e., ‘Locality 4’ of Lapparent and Aguirre, 1956b or 10 ‘Suterranya-Mina de lignit’ of Sellés & Vila, 2015); 3, Mina de Llordà; 4, Mina de Sant 11 Josep and Mina Consolació; 5, Mina El Collet; 6, ‘mines around Pobla de Lillet’; 7, 12 Mina de Sant Antoni; 8, mine around La Nou de Berguedà; 9, Mina Maria; 10, Mina 13 Tumí; 11, Mina Campos; 12, ‘mine around Cercs’; 13, Mina del Coll de Pradell; 14, 14 ‘between Suterranya and Vilamitjana’ (including the ‘Locality 3’ of Lapparent and 15 Aguirre, 1956b); 15, ‘between Suterranya and Orcau’; 16, ‘South of Vilamitjana’; 17, 16 ‘South of Fontsagrada’; 18, Orcau-1 (‘between Suterranya and Orcau’, at Barranc dels 17 Cantals; i.e., ‘Locality 5’ of Lapparent and Aguirre, 1956b); 19, ‘between Orcau and 18 Basturs’ (including the ‘Locality 7’ of Lapparent and Aguirre, 1956b equivalent to the 19 Orcau-2 locality of Ardèvol et al., 1995); 20, Barranc de la Costa Gran; 21, ‘between 20 Suterranya and Figuerola d’Orcau’; 22, ‘around Orcau’ (i.e. ‘Locality 6’ of Lapparent 21 and Aguirre, 1956b); 23, Barranc de Basturs (or Barranc dels Corrals) and Barranc de la 22 Costa Gran (including the ‘Locality 8’ of Lapparent and Aguirre, 1956,b and the egg 23 locality reported by Lapparent, 1958); 24, ‘between Basturs and Sant Romà d’Abella’ 24 (e.g. Barranc de les Collades); 25, ‘Barranco de Enmedio’ (Barranc de la Viella); 26, 25 Barranc de la Fonguera; 27, ‘from Orcau to Montesquiu’; 28, ‘between Cellers and 1 Moror’; 29, ‘between Moror, Sant Esteve de la Sarga, and Alsamora’ and ‘between Sant 2 Esteve de la Sarga and Cellers’ (including the locality ‘Moror’of Brinkmann (1984). 3 Localities/prospecting areas 2, 18, 22, 25, and 26 were prospected together with 4 Emiliano Aguirre in the 1955 survey. Maps from GoogleMaps 5 (https://www.google.es/maps/@42.1177987,0.9928178,12z/data=!5m1!1e4; 6 https://www.google.es/maps/@42.1860123,1.8782472,12z/data=!5m1!1e4) accessed 7 the 8 March 2022. 8 9 Figure 3. Document with the budget approval for the grant awarded by the Instituto 10 Lucas Mallada-CSIC to Walter Georg Kühne for the study of Cretaceous deposits in the 11 Pyrenees. July 26, 1954. ACN0773, courtesy of the archive of the Museo Nacional de 12 Ciencias Naturales. 13 14 Figure 4. Josep Nadal’s finding. A, Original handwritting notes of Walter G. Kühne on 15 his field notebook, on the 23rd of September 1954, the day he knew about Josep Nadal’s 16 fossil bone (courtesy of Urs and Anna Klebe, yellow shading text translated from 17 German: ‘ Indication Dino. Well preserved distal end of a metapodial. José Nadal from 18 Suterranea (sic) found the piece while hunting; in a barranca between Suterranea and 19 Orcau between 1950-52. The piece is dark brown, not light grey-blue of the adjacent 20 bones close east of Suterranea’); B, The specimen MNCN59304 found by Josep Nadal 21 (scale bar in cm) and currently housed at the Museo Nacional de Ciencias Naturales, in 22 Madrid; C, Letter by Bermudo Meléndez (Instituto Lucas Mallada) to Josep Nadal 23 (courtesy of Eugeni Nadal; yellow shading text translated from Spanish: ‘Mr. Kühne 24 gave us a fossil bone, collected by you, which corresponds to a phalanx of the metapod 25 (sic) of a dinosaur. Although the specimen itself has no commercial value, the Director 1 of this Instituto has decided to pay you the amount of 250 pesetas for the transfer of said 2 fossil to the Museo Nacional de Ciencias Naturales, as an expression of our gratitude for 3 the help provided to Mr. Kühne.’). 4 5 Figure 5. Sketches of the 1954 excavation made by Kühne on his field notes. The gully 6 with excavated bones in the Orcau site (above) and cross-section (North-South) view of 7 the excavation front with indication of some exposed bones (below). Text transcribed 8 and translated from German. 9 10 Figure 6. Excavation evaluation on the afternoon of August 17, 1955. A, Orthographic 11 view of the Barranc dels Cantals ravine with indication of the Orcau-1 locality (dashed 12 line indicates the itinerary to the site); B, Kühne and Aguirre walked from east 13 Suterranya to the ravine with the dinosaur fossils; C, Kühne (behind the black umbrella) 14 entering the ravine excavated in the Tremp Formation outcrops; D, the fossiliferous 15 gully ‘as it was before starting the works’ (rectangle marks the site, arrow indicates the 16 dip of the layers, North on the right; photography, indications and notes by Emiliano 17 Aguirre); E, Field sketch of the fossiliferous gully by Emiliano Aguirre (ACN0738). 18 Photos (Archivo MNCN-CSIC, ACN0738/003/003, ACN0738/003/003.22, 19 ACN0738/003/003.21) were taken by Emiliano Aguirre, courtesy of the archive of the 20 Museo Nacional de Ciencias Naturales. Orthographic photo by 21 http://www.icc.cat/vissir3/ (accessed the May 15, 2022). 22 23 Figure 7. Excavation works on early days. A, Walter Kühne (right) and Josep Montané 24 (left) on the afternoon of August 25, 1955, after removing manually part of the northern 25 and southern margins of the gully (on the right side is E. Aguirre’s beret, who took the 1 photo); B, The explosive technician Frederic Vergés (on the left) and Walter Kühne 2 preparing one of the five shot holes placed inside the gully on the morning of August, 3 26, 1955; C, Explosion of the dynamite shot holes in the fossiliferous locality (bottom 4 right corner); D, The explosive technicians Pere Fàbregas and Frederic Vergés, the 5 miner Josep Montané (standing from left to right), and Walter Kühne (from behind) 6 after the explosion and before the removal of the excess debris. Images (Archivo 7 MNCN-CSIC, ACN0738/003/003.1_a, ACN0738_003_003.15_a, 8 ACN0738_003_003.9_a, ACN0738_003_003.12_a) taken by E. Aguirre and courtesy 9 of the archive of the Museo Nacional de Ciencias Naturales. 10 11 Figure 8. Excavation and findings on the Orcau-1 locality. A, field scheme by Emiliano 12 Aguirre depicting the progress of the work space available on the site from the 24th to 13 30th, August 1955 (the scheme represents a North-South cross section of the 14 excavation, North on the right side); B, Josep Montané digging the excavation front on 15 the northern margin of the gully with the excavated 3-m deep hollow on behind him, 16 after the use of explosives (the jacketed bone to his lower right corresponds to 55/1; 17 August 31, 1955); C, Right femur (55/3) with an estimated proximodistal length of 130 18 cm (August 31, 1955; the pick handle equals 90 cm). Images (Archivo MNCN-CSIC, 19 ACN0738_003_003.6_a, ACN0738_003_003.4_a) taken by E. Aguirre and courtesy of 20 the archive of the Museo Nacional de Ciencias Naturales. 21 22 Figure 9. Mapping of bone accumulation in the Orcau-1 locality. A, General mapping of 23 the accumulation of bones, initiated by Kühne on September 1st, 1955; B, Detailed 24 sketch of the three articulated dorsal centra (55/6) (September 8, 1955); C, Detailed 25 sketch of the relative position of the left ilium (55/10), femur (‘femur 54’), and scapula 1 (55/9) (September 15, 1955); D, Detailed skecth of the relative position of the distal 2 ends of the left humerus (55/5) and left fibula (55/2). Transcribed and translated text 3 from German: (a) ‘turns out to be a small indefinable remain. Removed’; (b) ‘top view 4 of bone layer 45° falling to S’; (c) ‘1954 vertebrae not found’; (d) ‘ “Humerus” 5 extracted 1954’; (e) ‘end cutted by erosion’; (f), ‘basis of ‘Barranco’; (g) ‘top view of 6 the horizontally placed layer. Surface’; (h) ‘nothing here’; (i) ‘vertebrae not recovered. 7 10/09’; (j) ‘55/7; over 55/7, below 55/9’; (k) ‘55/6 cast of the impression of 3 vertebrae 8 of the lying surface (hanging wall surface was removed during preparation)’; (l) ‘cut 9 bone’; (m) ‘opisthocoelous’; (n) ‘concave to the front’; (o) ‘damage by excavation 10 workers (or other people digging there)’; (p) ‘still stuck in the mountain’; (q) ‘In both 11 parts of 55/2 there are parts of the end of 55/5 above at the (arrow)’; (r) ‘limb bones 12 in approximation’; (s) ‘55/2 in the footwall of 55/5’; (t) ‘damage due to faulting’; (u) 13 ‘end (is) cuttable’. 14 15 Figure 10. Prospected areas and examples of unusual fossils identified by Kühne near 16 Basturs (Tremp basin). A, the Barranc de la Costa Gran and Barranc de Basturs 17 outcrops, prospected by Kühne during the 19th and 20th of August, 1955; B, a dinosaur 18 (megaloolithid) egg from Basturs-2 eggsite, north of Barranc de Basturs. Kühne could 19 have described eggs like this as ‘15-20cm diameter ‘grey’ calcite-covered sphaeres’. 20 Scale bar equals 10 cm. Map from GoogleMaps 21 (https://www.google.es/maps/@42.1177987,0.9928178,12z/data=!5m1!1e4; accessed 22 the 8 March 2022). 23 24 Figure 11. The titanosaurian skeleton from Orcau-1. A, scheme depicting the 25 interpretation on how the sauropod skeleton was preserved at the site, drafted by Kühne 1 on his field notebook (September 14, 1955); B, Site map showing the skeletal elements 2 mapped during excavations since 1954. The position of the remains discovered in the 3 early excavations is based on sketches from Kühne’s field notes (Figure 9A). Table 1. Specimen list of the elements identified and collected by Walter Georg Kühne during the 1954 and 1955 excavations at the Orcau-1 locality. Observations transcripted and translated from German and based on the WGK field notes and reports. Element Field number Recovery year Kühne’s field observations Current repository number Three caudal unknown 1954 (two chevrons) “Chevron in 2 pieces”, “chevron. Very good [preservation]” (1954’s field MNCN 59539, MNCN 62760, chevrons 1955 (one chevron) notes). MNCN 59295 “One chevron degraded and packed (above 55/3)” (1955’s field notes) Right tibia N/A 1954 (3 parts) “A-C femur in 2 pieces+loose middle” (1954’s fieldnotes; Note: WGK MNCN79837-79838-79848 misidentified the tibia as a femur) Left femur “54A” and 1954 (54A) “Half limb bone detached from fault” (1954’s field notes) Unknown “54B” “Femur 1955 (54B) “Half of a limb bone whose other more accessible half was excavated in 54” 1954” (1955’s report). Undetermined 55/1 Unknown “Girdle bone, flat, in two pieces” (1955’s report). Unknown Left fibula 55/2 1955 “Half limb bone“ (1954’s field notes), “55/2 was the eastermost piece MNCN-79847 (distal half) when discovered in 1954” (1955’s field notes). “Limb bone. Part. The rest was destroyed by erosion on the outcrop of the fossil bed” (1955’s report). Right femur 55/3 1955 (3 parts) “Complete limb bone” (1955’s report) MCD-6987 (proximal third) Right humerus 55/4 1955 (2 parts) “Complete limb bone” (1955’s report) MCD-6988 (distal half) Left humerus 55/5 1955 (2 parts) “The humerus is about 160cm long, it is exposed along its entire length” MNCN-79834 (proximal half) (1954) “Complete limb bone” (1955’s report) 3 dorsal vertebrae 55/6 No “Non-extracted vertebra” (1955’s report) Probably MCD-6729 and MCD-6730 Left scapula 55/7 and 55/9 No “In the recovery of 55/5, the western corner of 55/7 [anterior end] was MCD-6715 (posterior end) destroyed before its girdle nature was recognized”, “55/7 might be part of 55/9”, “55/7 and 55/9 lifted off” (1955’s field notes). “Distal end [of 55/9] still on the field” (1955’s report). Undetermined 55/8 Unknown “short bone” (1955’s report) Unknown Ilium 55/10 “Pelvis. Several parts of this object were extracted, most of them are still Probably MCD-6731 (anterior on the field” (1955’s report). margin) Dorsal ribs 55/11 and No “Ribs. Their proximal ends are still on the field” (1955’s report); “Remains MCD-6721 (probably 55/12 of 10 under plaster” (1955’s field notes) corresponds to 55/11) Vertebra 55/13 Unknown “Of the vertebra of 55/13, which was favourably exposed with a clearly Unknown intact corpus, a complete preparation in two parts has been made, on which the preparator can prove whether the recovery of vertebrae is worthwhile.” (1955’s field notes). “Complete vertebra, in two parts” (1955’s report).