Tuebingosaurus maierfritzorum, Fernández & Werneburg, 2022

Fernandez, Omar Rafael Regalado & Werneburg, Ingmar, 2022, A new massopodan sauropodomorph from Trossingen Formation (Germany) hidden as ' Plateosaurus ' for 100 years in the historical Tuebingen collection, Vertebrate Zoology 72, pp. 771-822 : 771

Tuebingosaurus maierfritzorum sp. nov.

Diagnosis.

As for the type and only species.

Etymology.

The species name refers to Uwe Fritz and Wolfgang Maier. The former is the editor-in-chief of the journal Vertebrate Zoology, and, in his journal, he facilitated the Festschrift edited by Ingmar Werneburg and Irina Ruf in honour of Wolfgang Maier. The latter was a professor of evolutionary zoology in Tübingen from 1987 to 2007, and the Festschrift was published on the occasion of his 80th birthday in 2022.

Holotype.

GPIT-PV-30787, specimen historically referred to as ' GPIT IV’, comprising a complete pelvis (three sacral vertebrae, two ilia, two pubes, two ischia), five anterior caudal vertebrae, four chevrons, left femur, left tibia, left and right fibulae, left astragalus, left calcaneum, metatarsal I, pedal fingers 3 and 4 (Fig. 5 ).

Diagnosis.

Sauropodomorph with a unique combination of features: a fused pair of primordial sacrals; a robust and rugose expansion in the postacetabular process of the ilium; a pentagonal outline in the distal surface of the tibia, characterised by an additional posterior projection; a deep lateroventral fossa on the anterior margin of the astragalus; a ventrally directed heel with a lateral projection on the lateral articulation of the astragalus supporting the reduced calcaneum.

Description and comparison.

The anatomic terminology adopted in this work follows Galton and Upchurch (2004) for general anatomy, Wilson (1999) for vertebral laminae, Wilson et al. (2011) for vertebral fossae, and Wilson (2011) for the sacrum. Stacked photographs of the bones produced the plates Figs 6 - 18 , and the scale is an approximate reference. Every object has a scale in a different plane, roughly scaled up to the same size. However, for accurate measurements, please refer to the tables or the raw photographs stored in Morphobank.

Specimen GPIT-PV-30787 was referred to as P. ' Plateosaurus longiceps ' by Galton (2001b). The specimen was first illustrated by von Huene (1932) in his plate 38 and includes elements of the left forelimb (radius, metacarpal IV, phalanges from the fingers I, II and III), a sacrum with a pelvic girdle (including left and right ilia, left and right pubes, and left and right ischia), the first five anterior caudal vertebrae, and the left hindlimb (femur, tibia, fibula, and pes) ( von Huene 1932; Galton 2001a).

3.1.1. Sacrum (Figs 6 - 7 , Table 4 )

The sacrum of Tuebingosaurus maierfritzorum is composed of two sacrals and one caudosacral. Sacral 1 and sacral 2 have co-ossified neural spines, whereas the caudosacral is broken at the anterior corner of the neural spine, and it is not possible to know if the co-ossification extends all the neural height of the caudosacral (Fig. 6 ). Most early-diverging sauropodomorphs possess three sacral vertebrae, unlike early sauropods with four. Due to the distortion, it is possible to see more fine details through the left-hand side (Fig. 6 ). The neural spines of sacral 1 and sacral 2 have an expanded spinal table. The intercostal fenestrae are small and face ventrally (Fig. 6 ); the alar process of the sacral rib is extensive, articulating with most of the medial iliac surface, and the acetabular process is thinner and posteriorly displaced compared to the alar process (Fig. 7 ). The sacral ribs between sacrals 1 and 2 form a large dorsal intercostal foramen (icf1) (Fig. 7 ). Sacral 1 has an intercostal foramen that is anteriorly facing. The anterior articular surface of sacral 1 is slightly concave, with parallel lateral margins and a rounded ventral margin. The centrum of sacral 1 is fused to sacral 2, but the suture between them is still visible. The prezygapophyseal centrodiapophyseal fossa (prcdf) is discernible, with very thick centroprezygapophyseal lamina (cprl) and a thicker prezygodiapophyseal laminae (prdl). Sacral 1 has a spinoprezygapophyseal laminae (sprl) with a rounded margin that meets at the base of the neural spine, where they merge into a prespinal lamina (prsl). Sacral 1 also has a thick strut in the spinopostzygapophyseal lamina (spol) position. It is unclear if there is an intracostal foramen in the second sacral rib. The centrum of sacral 2 is not completely fused into the caudosacral, with a pronounced suture. Through icf1, it is possible to see that sacral 2 also has a prezygodiapophyseal lamina (prdl) and a prezygodiapophyseal fossa. The second ala of the sacrum is thicker than the first one, with a developed dorsal shelf in the alar process.

The anterior corner of the neural spine of the caudosacral is broken. The neural spine of the caudosacral also has an expanded dorsal table. The morphology of the caudosacral rib is similar to that of sacral rib 2, with the alar process expanding towards the iliac surface after a median depression that expands into the intracostal foramen 2. The caudosacral rib is not separated into alar and acetabular projections. The caudosacral rib articulates with the medial side of the Coloradisaurus brevis fossa, and a suture between these two elements is quite clear (Fig. 6 ). A cavity suggests a spinodiapophyseal lamina (spdl) in sacral 2 and a prespinal lamina (prsl) in the caudosacral (Fig. 6 ). The caudosacral has two developed rounded struts in the position of the spinopostzygapophyseal lamina (spol); they remain separated along with the height of the neural spine (Fig. 6 ).

3.1.2. Anterior caudal vertebrae (Fig. 8 - 9 , Table 5 )

The first five anterior caudal vertebrae are preserved (Fig. 8 ). The morphology of the vertebrae is typical of non-eusauropodan sauropodomorphs, amphicoelous, and constricted mediolaterally with a deeply concave ventral surface in lateral view. The ventral margin of the articular surfaces has a thickened lip that serves as the articulation point for the chevrons (= haemal arches). In Lufengosaurus and Antetonitrus Yates and Kitching, 2003, the centrum is higher than long, a trait also observed in Tuebingosaurus , and as in many early sauropodomorphs, the lamination is reduced. The neural arches extend along the centrum length, starting at the anterior articular surface and ending short of the posterior centrum margin.

The first caudal vertebra is attached to the sacrum (Figs 6 - 7 ). The posteroventral corner of the centrum has been remodelled with plaster. Unlike the sacrals, the first caudal is apneumatic. The posterior articular surface is markedly convex on the ventral end, but a concavity extends below the neural arch. The neural spine ends in a knob-like structure, not a dorsal table like the preceding sacral vertebrae. The spinoprezygapophyseal lamina (sprl) meets at the midline at the base of the neural spine and forms an expanded pre-spinal lamina. The spinopost-zygapophyseal laminae (spol) run from this knob-like structure to the postzygapophyses without forming a postspinal lamina. The diapophyses and the parapophyses are fused, but the former is longer than the latter allowing to distinguish both processes.

The second anterior caudal vertebra is obliquely twisted, with a deeply concave anterior articular surface and a shallow concave posterior articular surface (Fig. 8 ). The prezygapophyses, the postzygapophyses and the distal tip of the neural spine are broken. The ventral margin of the anterior articular surface has a large ventral lip for the chevron articulation, but the morphology of this process is difficult to assess due to distortion and breakage (Fig. 8 ). On both sides of the central body, there is a shallow concavity corresponding to a shallow centrodiapophyseal fossa (Fig. 7 ). The anterior articular surface is also more prominent than the posterior articular surface. The anterior margin of the neural spine is set more posteriorly than the position of the prezygapophyses, lending it a saddle-shaped outline, possibly due to a prominent spinoprezygapophyseal lamina (sprl) (Fig. 8 ). A distinct and broad anterior centrodiapophyseal lamina (acdl) is discernible. The spinopostzygapophyseal laminae run along the posterior margin of the neural spine, but the cortical bone is lost towards the tip, and it is impossible to know if they meet (Fig. 8 ).

Two anterior caudal vertebrae are preserved fused, and according to the illustration made by von Huene (1932) documenting the specimen, they correspond to the third and fourth caudal vertebrae. The vertebrae are dorsoventrally compressed on the right side (Fig. 8 ). The posterior part of the third anterior caudal neural arch is damaged, but a hypanthrum was present (Fig. 8 ). The neural canal is circular, and the diapophyses are oriented laterally (Fig. 8 ). It is not possible to discern the shape of the articular surface’s outline due to the distortion (Fig. 8 ). The ventral lips on the posterior surfaces are wider than the ventral lips on the anterior surfaces. The neural arch is twice as high as the central height in both vertebrae. The spinoprezygapophyseal laminae meet at the base of the neural spine, whereas the spinopostzygapophyseal laminae remain separated throughout the neural spine, and in the third anterior caudal, there is a somewhat deep sulcus separating the two laminae (Fig. 8 ). The neural spines retain a constant width and end in a rounded dorsal surface with no mediolateral expansion. The prezygapophyses of the third anterior caudal are broken at the tips, and they seem to be dorsolaterally oriented, whereas the prezygapo-physes of the fourth anterior caudal end in a point and are dorsally oriented. The anterior centrodiapophyseal lamina (acdl) is broad and short, only present in the second anterior vertebra (Fig. 8 ). The postzygapophyses are placed higher than the prezygapophyses in both neural arches.

The fifth anterior caudal vertebra is broken with part of the posterior half missing and has the same oblique twisting, even more markedly than in the preceding vertebrae (Fig. 8 ). As in the previous caudal vertebrae, the anterior articular surface is deeply concave, but the ventral margins are damaged, and the outline is unclear. The neural arch is slightly shorter than the centrum length, set posterior to the anterior articular surface and anterior to the posterior articular surface. The anterior margin of the neural spine is well set posterior to the anterior articular surface, aligned with the diapophysis. The prezygapo-physes do not have the same tip morphology as the preceding vertebrae; instead, they are dorsoventrally widened in the proximal part.

Four chevrons are preserved and based on the description by von Huene (1932), corresponding to the three anterior-most chevrons. The chevrons have a closed Y-shaped chevron, with two proximal rami placed on each side of the haemal canal and distally composed of a laterally compressed blade. Proximally, the haemal canal is closed by a bony bridge connecting both rami and closing the canal dorsally. The chevrons have a straight outline in lateral view (Fig. 9 ). All chevrons show signs of compressive deformation, and two are complete. In the two complete chevrons, it is possible to see a posterior grove extending until the blade’s mid-shaft (Fig. 9 ).

3.1.3. Ilium (Fig. 6 , Table 6 )

The pre-acetabular process resembles other early-diverging sauropodomorphs in being a triangular projection rather than a vertically tall subtriangular plate seen in more advanced sauropodomorphs. The pre-acetabular process is facing anteriorly in both lateral and dorsal views, and on both ilia, there is a bulge on the lateral surface of the processes. In addition, a preacetabular ridge is present in both ilia (Fig. 6 ).

The dorsal margin of the ilium is different on the left and right sides, suggesting a diagenetic distortion of the specimen that has slightly compressed the right-hand side and expanded the left-hand side (Fig. 6 ). The dorsal margin in the lateral view is convex in the middle portion, with two slight inflexions at the pre- and post-ace-tabular processes. The ilium of P. trossingensis (GPIT-PV-30784) has a sigmoid dorsal margin in lateral view, and in Melanorosaurus and Riojasaurus , the ilium is stepped. A stepped ilium is also present in the Ellingen material ( Moser 2003). The iliac blade is thinner dorsal to the acetabulum than the postacetabular process. The lateral surface of both ilia is concave along the anteroposterior and dorsoventral axes, but the degree of the concavity is different on both sides due to the distortion. This concave surface extends ventrally to a point close to the acetabular margin, as Meroktenos . In non-sauropod sauropodomorphs, this surface is restricted to the dorsal half of the iliac blade, as illustrated in Lufengosaurus ( Young 1941), the Ellingen material ( Moser 2003) and Riojasaurus (Bonaparte 1971). The iliac blade of Tuebingosaurus is very high, approximately two-thirds of the iliac height, a condition shared with Meroktenos .

The acetabulum is fully open like in most sauropodomorphs, except for Pantydraco (Galton and Ker-mack, 2010), Eoraptor Sereno et al., 1993 and Burio-lestes Cabreira et al., 2016. The acetabular region is dorsoventrally high with a pronounced medial wall, similar to the morphology described for Anchisaurus Marsh, 1885 ( Galton and Cluver 1976), and Yunnanosaurus youngi Lü et al., 2007.

The pubic peduncle is prominent and projects anteriorly to the anterior tip of the pre-acetabular process (Fig. 6 ). The transverse cross-section through the pubic peduncle is laterally expanded and medially narrow, giving it a D-shape in distal view. The lateral margin is expanded into a supraacetabular ridge extending well above the acetabulum, similar to P. trossingensis (GPIT-PV-30784). The pubic peduncle is distally expanded lateral view when compared to its base.

The ischial peduncle is prominent and anteroposteriorly wide, and the articular surface extends posteriorly, forming a ‘heel’ (Fig. 6 ), and this character is present in the Ellingen material ( Moser 2003), Riojasaurus (Heerden 1979) and Melanorosaurus ( Galton et al. 2005). However, the ischial heel in P. trossingensis (GPIT-PV-30785) and BSP 1962 ( Moser 2003) is more acute than in Tuebingosaurus . In addition, the ischial peduncle is positioned at the mid-length of the ilium, producing an elongated postacetabular process.

The postacetabular process comprises about 48% of the ilium length and is widened transversely towards the posterior-most corner of the postacetabular process, in contrast to the narrow dorsal margin like in Ruehleia (pers. obs.) and Lufengosaurus (pers. obs.). The ventral margin of the postacetabular process is ventrally deflected at the most posterodorsal corner and does not meet the posterodorsal margin of the postacetabular process (Fig. 6 ). The lateral profile of the postacetabular process is square-ended with rounded margins, as also occurs in more derived sauropodomorphs and contrasts with the acute lateral outline seen in other early-diverging sauropodomorphs such as Ruehleia (pers. obs.) and Jingshanosaurus . The base of the postacetabular process and the base of the ischial peduncle are connected by a strongly developed Coloradisaurus brevis fossa with an M-shaped posterior margin (Fig. 6 ). The Coloradisaurus brevis shelf is lost in sauropods but present in most dinosaurs as a plesiomorphic state (Gaton and Kermack, 2010). The postacetabular process of the ilium is 1.08 times longer than the distance between the ischiadic and the pubic peduncle (Table 6 ).

3.1.4. Pubis (Fig. 10 , Table 7 )

Both pubes are preserved, although the left pubis has the obturator plate medially broken and is deformed in the proximal end (Fig. 10 ). As in most early-diverging sauropodomorphs, the pubis is long and slender, whereas sauropods have broad pubes ( Galton and Upchurch 2004). The proximal end is slightly twisted and laterally expanded in the anterior view, followed by a plate-like shaft that continues towards the distal end (Fig. 10 ). The overall morphology is similar to that of Plateosaurus (SMNS 13200) and Antetonitrus (BP/1/4952), but in the medial view, the proximal end is anterodorsally expanded, as the condition in the Ellingen material (BSP 1962, in Pl. 30, Moser 2003). The iliac peduncle is not laterally expanded, giving the pubis straight medial and lateral margins in the anterior view, unlike the more derived condition in Antetonitrus and Vulcanodon Raath, 1972, that have a waisted outline, and the ‘intermediate’ slightly concave condition in Lufengosaurus and Massospondylus carinatus .

In P. trossingensis (SMNS 13200), the ischiadic articular surface is separated by an ample nonarticular surface from the iliac articular surface ( Moser 2003). In contrast, in Tuebingosaurus , the ischiadic articular surface is separated from the iliac articular surface by a deep borrow, giving the distinctive sauropodomorph morphology of inflexion in the proximal anterior pubic profile. This borrow is present on both pubes, although the iliac articular surface in the left pubes is broken off (Fig. 10 ). The obturator foramen is relatively large and fully visible in lateral view, unlike in Antetonitrus , where the iliac peduncle obscures the obturator foramen. The iliac pedicel of the pubis partially occludes the obturator foramen in anterior view, a character shared with Saturnalia Langer et al., 1999, and Guaibasaurus Bonaparte et al., 1999. The pubic plate is approximately one-quarter of the total pubic length, measured from the proximal articular surface of the iliac peduncle to the distal surface of the pubic apron, a condition also observed in the Ellingen material (BSP 1962, Pl. 30, Moser 2003), Adeopapposaurus , Lufengosaurus (pers. obs.), Antetonitrus and Meroktenos . In Lessemsaurus and Vulcanodon , the pubic plate is closer to a third of the pubic length and is almost half the length in eusauropods, e.g., Giraffatitan brancai (Janensch, 1914) (MB.R.2180). As in Coloradisaurus and Plateosaurus , the distal end of the pubic apron is markedly anteroposteriorly expanded, and unlike Antetonitrus , Riojasaurus and Meroktenos . There is a pubic tubercle present on the left pubis, very prominently and directly ventral to the obturator foramen, but the same area on the right pubis is damaged. This pubic tubercle is present in Efraasia , Plateosaurus and Plateosauravus ( Yates 2003b, 2007).

The conjoined width of the pubes represents 38% of the total length of the pubis (Table 7 ), unlike in more derived sauropodomorphs where the conjoined width of the pubes is larger than 75% of the pubic length. In addition, the minimum transverse width of the apron is 28% larger than the distance between the pubic and ischiadic peduncle of the ilium; a condition shared with most early-diverging sauropodomorphs and like more derived sauropodomorphs, where the width of the pubic apron is smaller than 40% of the distance between the iliac peduncles (Table 7 ).

3.1.5. Ischium (Fig. 11 , Table 8 )

Both ischia in Tuebingosaurus are preserved and fused along the midline (Fig. 11 ). As in many early-diverging sauropodomorphs, the ischia are almost rod-like and subtriangular structures where the ischiadic plate is the thinnest region and occupies the proximal third of the bone. As in Colorodisaurus , Plateosaurus and Lufengosaurus , the proximal plate is medially concave and laterally convex, but unlike Coloradisaurus and Plateosaurus , the distal end is not as dorsoventrally expanded and lacks their sub-ovoid morphology. The cortical end on the distal end is not preserved, and only the general morphology can be discerned, and it is not possible to know if there was a posteriorly directed heel as seen in SMNS 13200. Tuebingosaurus has a more strongly dorsoventrally expanded axis than the mediolateral axis, a condition shared with Lufengosaurus .

The pubic process is widest transversely at the acetabular margin and tapers ventrally, giving it a V-shaped outline (Fig. 11 ). The mediolateral expansion corresponds to a medial projection that makes the internal border of the acetabular foramen. The ventral margin is expanded in the proximal part of the ischium forming an obturator plate but drastically decreases where the ischiadic shaft starts, with a notch separating the posteroventral end of the ischial obturator plate and the ischial shaft, which then retains a constant dorsoventral width up to the distalmost third where the distal expansion starts (Yates and Kitching, 2003) (Fig. 11 ). The iliac peduncle has a distinctive morphology, as posterior to the iliac articular surface, there is a concavity followed by a posteriorly oriented projection, which is not seen in the original illustration ( von Huene 1932) nor other sauropodomorphs. Along the proximal part of the ischium is a well-developed and deep longitudinal dorsolateral sulcus, a common condition in sauropodomorphs (Fig. 11 ). In Tuebingosaurus , the ventral margins of the pubic process meet up to a third of the length of the ischiadic shaft, unlike in P. trossingensis (GPIT-PV-30784 and GPIT-PV-30785, as illustrated in Yates 2003a), and Lufengosaurus , where the margins met by the beginning of the ischium.

In Tuebingosaurus , the distal end of the ischiadic shaft ends in a distal expansion (Fig. 11 ). In the distal view, the medial margin that meets the antimere is higher than the lateral margin. Only the left ischium has the distal surface of the distal expansion preserved, showing a subquadrangular outline (Fig. 11 ). In Plateosaurus (SMNS 13200), the distal expansion has a more subtriangular outline, where the medial expansion is four times larger than the lateral margin, and the lateral margin ends more in a point. In Tuebingosaurus , the anteroposterior length of the medial margin is slightly shorter than the lateromedial length of the distal surface.

In contrast, in Plateosaurus (SMNS 13200), the anteroposterior length of the medial margin is almost three times as big as the lateromedial length, giving the distal expansion in Plateosaurus a more gracile shape. The morphology of the distal expansion is similar, then, to Lufengosaurus (pers. obs.) and Mussaurus ( Otero and Pol 2013). However, in the lateral view, the distal expansion has a small anterior projection, that in Plateosaurus (SMNS 13200) has more of a heel-like morphology, in Tuebingosaurus is more triangular; this triangular expansion is unlike Mussaurus ( Otero and Pol 2013) and Lufengosaurus (pers. obs.), where is a continuous expansion that starts from the midshaft.

3.1.6. Femur (Fig. 12 , Table 9 , 10 )

In Tuebingosaurus , only the left femur is partially preserved, missing most of the medial condyle, and the medial condyle is reconstructed in the distal end with plaster (Fig. 12 ). The femur has the general morphology seen in early sauropodomorphs, straight in an anterior view and curved in a lateral view ( Galton and Upchurch 2004, Fig. 12 ). In the earliest forms, like Buriolestes ( Müller et al. 2018), the femur is curved in the anterior and lateral view, whereas in more derived forms, like in Barapasaurus Jain et al., 1975 ( Bandyopadhyay et al. 2010), it is straight in both views. In specimen SMNS 13200, the femoral head is slightly visible in lateral view, not fully medially inturned, whereas, in Tuebingosaurus , the femoral head is completely inturned and hidden in lateral view.

The femoral head is broken on its anterior half, missing the anteromedial and anterolateral features. The sulcus for the ligamentum capitis femoralis is flat, compared to the marked concavity in Buriolestes ( Müller et al. 2018), followed by a markedly concave but narrow facies articularis antitrochanterica. No proximal groove is on the proximal surface, like the one seen in Buriolestes ( Müller et al. 2018).

The lesser trochanter is prominent, a feature shared with specimen SMNS 13200 ( Moser 2003), but unlike in SMNS 13200, the dorsolateral trochanter (= trochanter major) is only a small bump, whereas in SMNS 13200 is a more developed protuberance. In the fourth trochanter in SMNS 13200, the dorsal margin and the ventral are parallel and similarly slope dorsoventrally ( Moser 2003). The femur in Tuebingosaurus has the fourth trochanter with a dorsal margin running dorsoventrally and a ventral margin running more horizontally, giving the fourth trochanter a somewhat trapezoid shape (Fig. 12 ), quite similar to the morphology seen in Riojasaurus (Bonaparte 1972). In Coloradisaurus , the dorsal margin runs dorsoventrally but not so steeply, whereas the ventral margin runs ventrodorsally with a more pronounced slope, giving the fourth trochanter a distinctive trapezoidal shape in an inverted orientation compared to Riojasaurus ( Apaldetti et al. 2013). In Buriolestes ( Müller et al. 2018) and Anchisaurus ( Galton 1976), the fourth trochanter has a tra-pezoidal shape, with the dorsal margin running dorsoventrally and the ventral margin running ventrodorsally, both with similar slopes, giving the fourth trochanter a regular trapezoid shape. In Mussaurus ( Otero and Pol 2013), the dorsal and ventral margins run somewhat parallel, close to the horizontal, but have markedly curved edges. In Buriolestes ( Müller et al. 2018), the fourth trochanter is closer to the medial margin along the mediolateral axis. In the medial view, the medial surface expands continuously onto the fourth trochanter; in the lateral view, there is an inflexion separating the lateral surface from the fourth trochanter. This same condition is observed in SMNS 13200, where the medial surface is continuously expanded onto the fourth trochanter plate in anteromedial view but separated from the lateral surface by an inflexion. The fourth trochanter in Tuebingosaurus has the same morphology, and this condition can be found in other early sauropodomorphs, e.g., Riojasaurus (Bonaparte 1972), Anchisaurus ( Galton 1976), and Coloradisaurus ( Apaldetti et al., 2014). In Mussaurus ( Otero and Pol 2013), the fourth trochanter is closer to the lateral side, and the lateral surface continuously expands onto the fourth trochanter, whereas a marked inflexion separates the posterior surface from the fourth trochanter.

In the distal view, the median portion of the femur is reconstructed by plaster, but the outline seems more ovoid (Fig. 12 ). For instance, in SMNS 13200 and Coloradisaurus , the mediolateral axis is considerably longer than the anteroposterior one, giving the distal surface a more flattened elliptical shape. In Mussaurus , the distal end is hourglass-shaped, with a marked popliteal fossa posterior and a deep extensor depression anteriorly. Due to the plaster, it is impossible to know which of these two morphotypes is present in the femur. An extensor depression is present in most sauropodomorphs, except for the earliest forms, such as Buriolestes , Saturnalia , Pantydraco and Efraasia (SMNS 12216, pers. obs.). The plaster in the specimen does not outline an extensor depression, imitating the plesiomorphic condition. In Buriolestes ( Müller et al. 2018), the medial condyle and the anterolateral tuber are similar, with a very lateromedially reduced lateral condyle. In Coloradisaurus , the medial condyle is the most prominent of the three condyles, and the tibiofibular condyle has a triangular outline, unlike the quadrangular one seen in earlier forms. The lateral condyle is laterally projected and separated from the tibiofibular condyle by a significant inflexion. The condylar morphology of Coloradisaurus is also seen in SMNS 13200 and Anchisaurus ( Galton 1976). Despite the plaster, the medial condyle is larger in the lateromedial axis than the tibiofibular condyle. The lateral condyle is laterally projected and separated from the tibiofibular condyle by an inflexion, although not as marked as in Coloradisaurus . The morphology in Mussaurus is unclear, as this portion is broken off ( Otero and Pol 2013). Furthermore, a Ward clustering of the measurements in sauropodomorph femora in Table 10 , showing Tuebingosaurus is placed in a cluster with Mussaurus and Lessemsaurus (Appendix 3, Figure A1).

3.1.7. Tibia (Fig. 13 , Table 11 )

The tibia is approximately 0.85 times the length of the femur (Tables 9 and 11 ), a proportion similar to all non-eusauropod sauropodomorphs ( Apaldetti et al. 2013). The anteroposterior axis of the proximal end is horizontal in lateral view as in Mussaurus and Anchisaurus , whereas the anteroposterior axis in specimen SMNS 13200 and Coloradisaurus is dorsoventrally skewed. In the proximal view, the proximal end of the tibia has a scalene shape, with the medial condyle posteriorly expanded relative to the medial condyle and the cnemial crest facing laterally (Fig. 13 ). In specimen SMNS 13200, the medial and lateral condyles are roughly aligned, and the cnemial crest is more anteriorly oriented. In Coloradisaurus , the medial and lateral condyles are roughly aligned, but the cnemial crest is laterally oriented, whereas, in Mussaurus , the proximal outline is similar to that of specimen Tuebingosaurus . In earlier forms, such as in Buriolestes , the cnemial crest is laterally oriented, forming a 90 degrees angle with the anteroposterior axis of the proximal end of the tibia. In Tuebingosaurus , the fibular articular surface has a large protuberance, similar to the outline in SMNS 13200, although this protuberance is less pronounced. In Mussaurus and Coloradisaurus , this protuberance is more like a small tuber (Fig. 13 ).

The shaft of the tibia is straight with a sub-elliptical cross-section. The distal end has a quadrangular outline, with two lateral processes, the anterolateral and posterolateral processes, and a posteromedial and an anterolateral condyle (Fig. 13 ). The anterolateral process is twice as wide as the posterolateral process. In Tuebingosaurus , the medial surface has an additional projection not seen in other sauropodomorphs. In Coloradisaurus , the anteromedial process is medially expanded relative to the posteromedial condyle, a feature seen in Adeopapposaurus , Mussaurus and SMNS 13200. The distal end is lateromedially elongated, and in the posterior view, the posterolateral process (= posteroventral process, = caudoventral process) is distally expanded relative to the anterolateral process and reaches the lateral margin of the distal tibia, a condition shared with SMNS 13200, Riojasaurus , Adeopapposaurus and Coloradisaurus , but unlike Mussaurus , Anchisaurus and Aardonyx Yates et al., 2010, and other advanced sauropodomorphs, where the posterolateral process does not reach the lateral margin. As in most early sauropodomorphs, the posterolateral process distally exceeds the limits of the anterolateral process. The distal surface of the posterolateral process is horizontally oriented, whereas the distal surface of the anterolateral process is distolaterally oblique for the articulation of the ascending process of the astragalus.

Tuebingosaurus sits between the morphospaces outlined for Massospondylidae and " Melanorosauridae " in a bivariate plot of the ratios between the total length and anteroposterior depth of the proximal end of the tibia (L/Pw) concerning the ratio between the total length and anteroposterior depth at mid-length of the tibia (L/Mw) (Fig. 14 ). Noteworthy, Plateosaurus has a large morphospace, compared to the other sauropodomorphs in the sample. First, this could represent that the morphospace of Plateosaurus captures better the intraspecific variability in the tibiae given the larger sample compared to other sauropodomorphs; however, the gradual increase in the robustness through time is quite clear. Furthermore, a restricted definition of Plateosaurus (SMNS 13200 and GPIT-PV-30785) occupies a similar space in the bivariate plot. Specimen BSP 1962 is, on the other hand, nested within " Melanorosauridae ", close to Tuebingosaurus and Mussaurus , and supports the idea that the similarity between Tuebingosaurus and BSP 1962 outlined above in the pubis, ischia and the tibiae are better explained by considering BSP 1962 as a massopodan as well (Appendix 3-Figure A2).

3.1.8. Fibula (Fig. 15 , Table 12 )

The two fibulae are preserved and have similar sizes. The fibula is a slender and long bone with an anteroposteriorly expanded proximal end and, to a lesser degree, the distal end (Fig. 15 ), similar to the condition in Riojasaurus , unlike in Anchisaurus and Mussaurus , where the distal end is not expanded. The proximal articular surface has a concave medial margin and a convex lateral margin, forming a crescent-shaped outline as in SMNS 13200, Adeopapposaurus and Mussaurus . However, in Tuebingosaurus , the medial margin is concave only in the anterior portion and straight in the posterior one. The shaft is straight in lateral and anterior views, unlike in Adeopapposaurus and Mussaurus , where the fibula is curved in anterior view. The distal end in lateral view is anteriorly slanted but horizontal in posterior view, as in Mussaurus and Adeopapposaurus . There is a small protuberance on the anteromedial surface, a feature that has not been reported for sauropodomorphs and is present on both fibulae, discarding a noticeable pathological feature (mfp in Fig. 15 ). The medial condyle is larger than the lateral condyle, and a shallow triangular fossa is visible on the medial face of the distal end of the fibula. The lateral face of the fibula is, in turn, flat.

3.1.9. Astragalus (Fig. 16 , Table 13 )

The astragalus has the classic non-eusauropod sauropodomorph morphology, with a somewhat kidney--shaped outline (Fig. 16 ). In dorsal view, the medial margin is about 50% larger than the lateral margin; the lateral margin has a sigmoidal articulation, and the medial margin is posteriorly curved. The posterior margin is convex, as in Mussaurus ( Otero and Pol 2013), Blikanasaurus Galton and van Heerden, 1985 (Galton and van Heerden 1998), Vulcanodon ( Cooper 1984), and Tazoudasaurus Allain et al., 2004 ( Allain and Aquesbi 2008); nevertheless, a convex posterior margin is also present in P. trossingensis (as illustrated in von Huene 1926).

The posterior margin is straight in Unaysaurus Leal et al., 2004 ( McPhee et al. 2019) and Macrocollum Müller et al., 2018. The medial margin in Unaysaurus , Macrocollum and Blikanasaurus has a prominent triangular process anteromedially projected, similar to the outline in Tuebingosaurus . At the midlength of the posterior margin, there is a prominent bulge like that present in Mussaurus , and a bulge is present in Blikanasaurus and P. trossingensis but not as pronounced (Fig. 16 ). The anterior margin has its highest point on the medial side, whereas the posterior margin has its highest point on the lateral side. The proximal surface is divided into two distinct articular facets: a lateral facet, with a deep socket-like concavity for the articulation with the distal end of the fibula, and a flat medial facet occupying most of the proximal surface, where the distal end of the tibia articulates with the astragalus. These two facets are divided by a rounded ridge that continues to form the posterior margin of the ascending process. As in many other early sauropodomorphs, the ascending process is not as prominent, and in anterior view, the ascending process rises slightly above the posterior bulge. Towards the lateral end of the anterior margin, there is a deep depression similar to those in early saurischians, e.g., Herrerasaurus Reig, 1963, Eoraptor ( Sereno et al., 2012), and Saturnalia Langer (2003), but faces anterolaterally rather than lateroventrally, and it is placed right beneath the anterior margin of the ascending process. This fossa occupies a prominent space of the anterior margin, and it is not a feature seen in other early sauropodomorphs. Ventral to this fossa, a ventrally directed projection with a heel-like morphology supports the calcaneum by a laterally oriented projection. The distal surface has the characteristic rugose roller-shaped articulation in other sauropodomorphs.

3.1.10. Calcaneum (Fig. 16 -A, D, Table 13 )

The calcaneum in Tuebingosaurus is significantly reduced, albeit conserving the early-diverging sauropodomorph triradiate morphology. The calcaneum is lateromedially flattened, but the anterior end is thicker than the posterior end and lacriform in dorsal view. The anterior end is not straight but bears a distinct anterior projection in the anterolateral margin. The ventral process rests on the anterolateral projection of the lateral margin of the astragalus. The medial margin of the calcaneum is concave and articulates along the sigmoidal lateral margin of the astragalus. This articulation generates a pocket between the two elements that were probably filled with cartilage. The mediolateral length of the calcaneum represents 21% of the astragalar mediolateral length. In early sauropodomorphs, such as Saturnalia , the calcaneal length is roughly 50% of the astragalar length, and in Coloradisaurus , it is 40%, and towards the more derived sauropodomorphs, we have values lower than 30%, such as in Anchisaurus , Vulcanodon , Shunosaurus Dong et al., 1983 and Camarasaurus Cope, 1877. This reduced calcaneum is consistent with what we expect in more obligated quadrupedal animals, such as sauropods.

3.1.11. Metatarsal IV (Fig. 17 , Table 13 )

According to the early drawings by von Huene (unpublished), an almost complete pes was recovered from the block as part of specimen " GPIT IV". The drawings show metatarsals I, II, III, and IV articulated to their respective phalanges. Currently, only metatarsal IV, the complete digits II and III, and one phalange of digit I are preserved in the collection (Fig. 17 ).

The only metatarsal element preserved is metatarsal IV. The metatarsal IV is a robust element with a constriction along the mid-section. Its proximal end is expanded lateromedially and flattened dorsoplantarly, whereas the distal end is expanded not as lateromedially but expanded dorsoplantarly, with a morphology similar to Massispondylus carinatus (BPI/I/4377) and Mussaurus (MLP 61-III-20-22) (Fig. 17 ). A well-developed crest on the proximal end extends proximodistally along the dorsal surface of the proximal end. This crest delimits a concave medial surface where metatarsal III articulates. The dorsoventral length at the crest level represents 30% of the lateromedial length of the proximal end of metatarsal IV, as in Mussaurus and Massospondylus , whereas this ratio reaches 50% in Saturnalia , Coloradisaurus , Plateosaurus , and Blikanasaurus .

The dorsal and plantar edges of the lateral half are parallel through the metatarsal length (Fig. 17 ), as in Mussaurus . The cross-section is ovoid, where the lateral margin is narrower than the medial one. The medial margin of metatarsal IV has a bulge close to the proximal end, a feature in Massospondylus , Mussaurus and Plateosaurus . In other early-branching sauropodomorphs, this bulge fits in a slight depression on the lateral margin of the shaft of metatarsal III. Distally, there is another bulge along the distal end of the shaft of metatarsal IV, a condition shared with Mussaurus .

The distal articular surface is quadrangular in distal view with an undivided and marked convexity, similar to Riojasaurus (PVL 3526). The lateral margin on the distal end has two processes that project laterally in distal view, whereas the medial margin has a marked expansion in the medio-plantar corner. On the lateral margin, the two projections are separated by a well-developed concavity; the medial margin is roughly straight.

3.1.12. Pedal digits (Fig. 18 , Table 13 )

Only two digits are preserved, pedal digit II and pedal digit III, with two and three phalanges, respectively, and the first phalanx of digit I. Phalanx I.1 is identified due to the morphology, with a proximomedial projection (Fig. 18 ) like the morphology reported in Plateosaurus ( von Huene 1926) but more developed. The proximal lateromedial width corresponds to 84% of the total proximodistal length of the phalange (Table 14 ). The proximal articular surface is concave, reniform and undivided with a concave dorsal edge and a convex ventral edge. The major axis of the proximal articular surface is twisted 5o to the lateromedial axis of the distal surface. The shaft has subparallel lateral and medial margins, with a flat dorsal surface and a deeply concave plantar surface. The distal margin has two well-developed condyles separated by an intercondylar groove. The dorsoplantar length of the lateral and medial condyles is roughly the same, but the medial collateral ligament pit is more deeply concave.

Pedal digit II has two non-terminal phalanges and a well-developed ungual. Phalanx II.1 is robust, where the proximal lateromedial length is 78% of the proximodistal length. In phalanx II.1, the distal lateromedial length is similar to the lateromedial length, with a distinctive shaft with concave lateral and medial margins. The dorsal margin of the proximal articular surface of phalanx II.1 is shorter than the ventral margin. On the distal end, there is a distinctive dorsal depression (Fig. 18 ). The collateral ligament pits are not deeply excavated. A markedly concave intercondylar groove separates the lateral and medial condyles. Phalanx II.2 is shorter than II.1, with similar robustness to phalanx II.1 (proximal lateromedial length is 79% of the proximodistal length). The lateral and medial margins of phalanx II.2 are more concave, and the shaft is comparatively shorter than the one in phalanx II.1 (Fig. 18 ). The collateral ligament pits of phalanx II.2 are more deeply marked and seem to face dorsally, although this could be the product of deformation. Phalanx II.2 has a distinctive dorsal flange. The ungual pedal digit II is lateromedially flattened and distinctively curved. The articular surface is undivided.

Pedal digit III has three non-terminal phalanges. Phalanx III.1 is robust, with the proximal lateromedial length being 72% of the proximodistal length. The shaft of phalanx III.1 is defined by markedly concave lateral and medial margins (Fig. 18 ). The dorsal surface is slightly concave, but the plantar one is strongly concave. Phalanx III.1 has a more hour-glass shape than phalanx II.1. The dorsal margin of the proximal articular surface of phalanx III.1 is shorter than the ventral margin, and this morphology is also seen in the other non-terminal phalanges of pedal digit III. Phalanx III.1 has a very developed dorsal flange and a very developed ventral flange. Phalanx III.2 is also robust (proximal lateromedial length is 73% of the proximodistal length), with a more open concave lateral margin. The dorsal flange of phalanx III.2 is more reduced than in phalanx III.1, but the ventral flange is still prominent. The collateral ligament pits are deeply excavated (Fig. 18 ). Phalanx III.3 is more robust than the preceding phalanges, with the proximal lateromedial length representing 83% of the proximodistal length of the phalanx. The medial and lateral condyles are more defined than the preceding phalanges, and the collateral ligament pits are more deeply excavated. The pedal ungual III is more curved than pedal ungual II (Fig. 18 ).

3.1.13. Other material previously associated with specimen " GPIT IV"

According to von Huene (1932), during the expedition of 1922 in the Trossingen Formation near Tübingen. It is impossible to know how nearby these elements were to the pelvis and hind limb of Tuebingosaurus , as von Huene (1932) did not provide details on this. In two separate blocks located near the semi-articulated specimen described above, there was a mandible (in block 169), a partially articulated forearm (block 185) and a cervical vertebra (block 159). The mandible has a similar outline to P. trossingensis , with 24 alveoli and 23 preserved (3rd tooth is missing); the mandible is damaged due to post-excavation preparation. The forearm elements correspond to a radius, a metacarpal (possibly metacarpal III, and manual digits I to III (digit I is complete, digit II is probably missing one phalange, and digit III only has two phalanges). The radius is more straightened and less mediolaterally twisted than that of GPIT-PV-30785 and has a proximal outline that is more similar to Plateosauravus (based on the drawings in Remes 2007). The preservation of the bone is also slightly better than the preservation of the elements outlined above. There is no evident distortion; the cortical bone is not flaked like the other long elements in Tuebingosaurus , suggesting a faster burial and less environmental exposure. It could be possible that the forearm got buried earlier than the rest of the carcass. The cervical vertebrae could not be located in the collection.

Furthermore, there are no relevant details or documentation regarding the excavation from 1922 available to us. The pelvis, the hind limb, and the caudal vertebrae articulate with each other, and it is possible to associate them with a single individual, whereas the other bones are associated with this based on their distance to the larger block. These specimens were embedded into a plastic matrix as part of the diorama display to simulate the mud-burial. When trying to remove the mandible, it was clear that the material was glued to the plastic, and its removal may endanger the specimens. Thus, the mandible and the forearm are removed from specimen GPIT-PV-30787 and, as such, from the holotype of Tuebingosaurus . However, further work should test whether these specimens can be referred to the holotype.

Figures

Figure 5. Reconstruction of Tuebingosaurus maierfritzorum gen. et sp. nov. as a quadruped dinosaur, using the outline of Riojasaurus as a base - next to the silhouette of Friedrich von Huene. The drawing of the bones is based on and modified from the original illustrations of specimen " GPIT IV " in von Huene (1932, pl. 38) that have been replicated in the literature. The right fibula is marked in grey as it was found nearby with similar measurements to the left fibula and has been assumed to be part of the same individual.

Figure 6. Ilia, sacrum and anterior caudal vertebra of Tuebingosaurus maierfritzorum (GPIT-PV- 30787). A right lateral view; B posterior view; C anterior view; D dorsal view. Abbreviations: bf, Coloradisaurus brevis fossa; Ca 1, anterior caudal 1; CS, caudosacral; csr, caudal sacral rib; ib, iliac blade; ilp, ischiadic peduncle; isva 1,2, intercostal space ventral aperture; paf, preacetabular fossa; pap, preacetabular process; par, iliac preacetabular ridge; pop, postacetabular process; prz, prezygapophyses; pup, pubic peduncle; S 1, sacral 1; S 2, sacral 2; sac, supracetabular crest; sr 1, sacral rib 1; sr 2, sacral rib 2.

Figure 7. Surface scan of the pelvis of Tuebingosaurus maierfritzorum (GPIT-PV- 30787) in posterodorsal view and some cross sections organised from the anterior to the posterior views. A Cross sections in sagittal planes along the first primordial sacral 1 ordered along the anteroposterior axis. B Cross sections in sagittal planes along the primordial sacral 2 ordered along the anteroposterior axis. C Cross sections in sagittal planes along the caudosacral vertebra are ordered along the anteroposterior axis. Abbreviations: icf 1, intracostal fenestra 1; icf 2, intracostal fenestra 2; icf 3, intracostal fenestra 3; il, ilium; ip, ischidiac peduncle; ns, neural spine; rs 1, sacral rib 1; rs 2, sacral rib 2; rs 3, sacral rib 3; sa, supraacetabular crest.

Figure 8. Anterior caudal vertebrae of Tuebingosaurus maierfritzorum (GPIT-PV- 30787): A - E second anterior caudal vertebrae; F - I third and fourth anterior caudal vertebrae; J - L fifth anterior caudal vertebrae; in right lateral (A, F, J), in dorsal (B, I, L), in anterior (C, G, K), in posterior (D, H), and ventral (E) views. Abbreviations: cva, chevron articular surface, d, diapophysis, ns, neural spine, pr, prezygapophyses, pr 1, prezygapophysis in third anterior caudal, pr 2, prezygapophysis in fourth anterior caudal, pz, postzygapophysis, spof, spinopostzygapophseal fossa, spol, spinopostzygapophyseal lamina, sprf, spinoprezygapophseal fossa, sprl, spinoprezygapophyseal lamina.

Figure 9. Chevrons of Tuebingosaurus maierfritzorum (GPIT-PV- 30787) in anterior (A, C, F, G), posterior (B) and right lateral (D, E) views. Abbreviations: b, chevron blade, bb, bony bridge, car, chevron articular surface, hc, haemal canal, pg, posterior groove.

Figure 10. Pubes of Tuebingosaurus maierfritzorum (GPIT-PV- 30787). A - C Right pubis in (A) lateral, (B) anterior, (C) medial views. D - F Left pubis in (D) posterior, (E) anterior, (F) lateral views. Abbreviations: am, acetabular margin; ap, pubic apron; ila, iliac articular surface; ip, ischiadic peduncle; isa, ischiadic articular surface; ml, median lamina; op, obturator plate; pp, proximal plate. Scale bar: 50 mm.

Figure 11. Conjoined ischia of Tuebingosaurus maierfritzorum (GPIT-PV- 30787). A right lateral view; B proximal view; C left lateral view; D distal view. Abbreviations: am, acetabular margin; ari, articular surface for the ilium; arp, articular surface for the pubis; de, distal expansion; dr, dorsal ridge; nf, non-articular fossa; op, obturator plate; vm, ventral margin.

Figure 12. Left femur of Tuebingosaurus maierfritzorum (GPIT-PV- 30787) in (A) posterior, (B) medial, (C) anterior, (D) lateral, (E) proximal, (F) distal views. The medial condyle is separated from the rest of the bone by plaster, and the shape of the medial condyle is reconstructed as a square, following a typical morphology in early diverging sauropodomorphs. The panel below shows the distal outlines in other non-sauropod sauropodomorphs: Yunnanosaurus huangi (IVPP V 20), Lufengosaurus (IVPP V 15), Plateosaurus (SMNS 13200), Coloradisaurus (PVL 5904), Sarahsaurus (TMM 43646 - 2), Mussaurus (MLP 68 - II- 27 - 1 specimen A). Abbreviations: fh, femoral head; ft, fourth trochanter; lc, lateral condyle; lt, lesser (= anterior) trochanter; mc, medial condyle; tfc, tibiofibular crest; ts, trochanteric shelf.

Figure 13. Left tibia of Tuebingosaurus maierfritzorum (GPIT-PV- 30787) in the centre, and outlines in other sauropodomorphs for comparisons. The left tibia is shown in (A) proximal, (B) lateral, (C) medial and (D) distal views. The panels to the left and right show the proximal and distal outlines, respectively, of four sauropodomorphs: Plateosaurus (SMNS 13200), Coloradisaurus (PVL 5904), Mussaurus (MLP 68 - II- 27 - 1) and Tazoudasaurus (To 1 - 380). The outlines are not set to scale. Abbreviations: alp, anterolateral process, aspa, articular surface for the ascending process, cn, cnemial crest, lc, lateral condyle, mc, medial condyle, plp, posterolateral process.

Figure 14. Bivariate plot showing the ratio between the total length and anteroposterior depth of the proximal end of the tibia (L / Pw) concerning the ratio between the total length and anteroposterior depth at mid-length of the tibia (L / Mw). Data was taken from Ezcurra and Apaldetti (2011) and first-hand assessments obtained by ORRF. The convex hulls with solid lines show the morphospace generated by the groups ' Guaibasauridae ', Massospondylidae, ' Melanorosauridae ' and Sauropoda. The name ' Melanorosauridae ' is here used to refer to sauropodomorphs that are not traditionally considered as sauropods. The triangles represent taxa traditionally considered sauropods, and the stars represent non-sauropod sauropodomorphs. The colours of the points represent the age of the taxa, with purple for the Late Triassic and blue for the Early Jurassic. The dashed convex hull represents the morphospace corresponding to Plateosaurus as currently defined. The yellow convex hull represents the taxa placed in a polytomy before the diversification of Massospondylidae and Sauropodiformes.

Figure 15. Left fibula of Tuebingosaurus maierfritzorum (GPIT-PV- 30787) in (A) anterior, (B) medial, (C) proximal, (D) distal anteromedial view of the fibular, (E) distal views. Abbreviations: asa, astragalar articular surface, caa, calcaneum articular surface, mfp, anteromedial fibular process, tia, tibial articular surface.

Figure 16. Astragalus of Tuebingosaurus in (A) dorsal, (B) posterior and (C) anterior views. Calcaneus in A) dorsal and D) lateral views. The panel to the bottom left shows the astragali in other sauropodomorphs: Plateosaurus (SMNS 13200, in posterior view and articulated with the tibia), Mussaurus (MLP 68 - II- 27 - 1 specimen A), Tazoudasaurus (To 1 - 31, mirrored), Coloradisaurus (PVL 3967). The panel to the right shows the astragali in other sauropodomorphs in dorsal view: Plateosaurus (SMNS 13200), Mussaurus (MLP 68 - II- 27 - 1 specimen A, mirrored), Tazoudasaurus (To 1 - 31, mirrored), Coloradisaurus (PVL 3967, mirrored). Abbreviations: asp, ascending process; afo, anterior foramen; cas, concavity of the posterior surface of the ascending process; fdp, facet for descending process of the tibia; ff, fibular facet; pf, posterior fossa; pmc, posteromedial corner. The yellow dotted line represents the astragalar-calcaneum articulation.

Figure 17. Pes of Tuebingosaurus maierfritzorum (GPIT-PV- 30787). A Reconstruction of the pes of Tuebingosaurus maierfritzorum as illustrated by von Huene (Pl. 38, fig. 10). The elements coloured in brown correspond to the only material that has been located in the collection. Metatarsal IV in (B) plantar, (C) dorsal, (D) proximal, and (E) distal views. The panel to the right shows the proximal outlines of the metatarsals of four sauropodomorphs: Lufengosaurus (IVPP V 15), Mussaurus (MLP 61 - III- 20 - 22, Otero and Pol 2013, mirrored), Coloradisaurus (PVL 5904, Apaldetti et al. 2013, mirrored), and Blikanasaurus (Galton and Van Heerden 1998). Abbreviations: d, dorsal; p, plantar; dc, dorsal crest; mtI (I), metatarsal I; mtII (II), metatarsal II; mtIII (III), metatarsal III; mt III cs, contact surface of metatarsal III; mtIV (and IV), metatarsal IV; mtV cs, metatarsal V contact surface; V, metatarsal V.

Figure 18. Pedal phalanges I to III of Tuebingosaurus maierfritzorum (GPIT-PV- 30787). A - E Phalanx I. 1, in dorsal (A), ventral (B), distal (C), proximal (D), right lateral I views (F). Pedal digit II in dorsal view: G - I Phalanx II. 2 in left lateral (G), proximal (H) and distal (I) views, (J) ungual II in left lateral view, (K) Pedal digit III in dorsal view. L - M Phalanx III. 1 in left lateral (L) and distal (M) views, (N) Phalanx III. 2 in left lateral view, (O) Phalanx III. 3 in left lateral view and, (P) ungual III in left lateral view. The outlines on the left corner, reconstructions of the feet of Plateosaurus (SMNS 13200), and Blikanasaurus (Galton and van Heerden 1998). Abbreviations: colp, collateral ligament pit, dd, dorsal depression, mf, medial flange, I, pedal digit I, V pedal digit V.