Aragosaurus ischiaticus, SANZ ET AL., 1987

Royo-Torres, Rafael, Upchurch, Paul, Mannion, Philip D., Mas, Ramón, Cobos, Alberto, Gascó, Francisco, Alcalá, Luis & Sanz, José Luis, 2014, The anatomy, phylogenetic relationships, and stratigraphic position of the Tithonian-Berriasian Spanish sauropod dinosaur Aragosaurus ischiaticus, Zoological Journal of the Linnean Society 171 (3), pp. 623-655 : 630-644

ARAGOSAURUS ISCHIATICUS SANZ ET AL., 1987

Holotype

Aragosaurus ischiaticus is known from a partial, associated postcranial skeleton, comprising: seven dorsal rib fragments, IG 468 ( V40 ), IG 481 (Cos), IG 487 (Phs1), IG 492 (Uls), V20 ; 14 caudal vertebrae, IG 453 ( V8 ), IG 473 ( V1 ), IG 474 ( V2 s), IG 450 bis ( V5 ), IG 475 ( V3 ), IG 476 ( V4 ), IG 477 ( V5 ), IG 479 ( V7 ), IG 480 ( V8 ), ZH-18, ZH-17, ZH-12, ZH-15, ZH-16; two caudal neural arches, IG 468 ( V55 and X3); one caudal neural spine, IG 493 ( V9 s); eight chevrons, ZH-4, ZH-5, ZH- 7, ZH-8, ZH-9, ZH-11, ZH-13, ZH-14; a right scapula, ZH-1; a distal fragment of the left scapula, IG 482 (Oms); a left coracoid, IG 482 (Oms); a right humerus, IG 490 (Fes); a right ulna, IG 483 (Cu); a right radius, IG 484 (Ra); a right carpal, IG 485 (Cars); a right metacarpal I, IG 486 (rmc1); a right metacarpal II, IG 486 (rmc2); remains of metacarpals III and IV, IG 486 (rmc3), IG 486 (rmc4); a right pubis, IG 489 (Pus); a right ischium, ZH-3; a partial left ischium, IG 492 (Uls), IG 488 (Is); a left femur, ZH-2; two pedal phalanges, ZH-6, ZH- 10; and one ungual pedal phalanx, ZH-19.

Type locality and horizon

Las Zabacheras site, Villar del Arzobispo Formation (upper Tithonian–lower Berriasian).

Revised species diagnosis

Aragosaurus ischiaticus is diagnosed on the basis of the following new autapomorphies identified in the current study: (1) anterior caudal vertebrae possess neural spine summits with shallow, dorsolaterally facing concavities on either side of the midline; (2) small epipophysis-like protuberances on the dorsal surfaces of middle caudal vertebral postzygapophyses; (3) the long interosseous ridges on the ulna and radius represent at least a local autapomorphy, which is convergent with derived titanosaurs; (4) the interosseous ridge on the posterolateral face of the radial shaft terminates distally in a distinct tubercle; (5) carpal subquadrangular in shape in proximal and distal views, with similar lateromedial and anteroposterior diameters; (6) proximal pedal phalanx ( II- 1 or III- 1) possesses a midline ridge on its dorsal surface, where its lateral and medial faces meet each other to form an apex.

Additional comments

Despite the complicated history of the collection, all the bones belong to a single individual. All of them come from the same site, show the same preservation, there is no repetition of elements, and their relative sizes are consistent. A tooth described by Sanz (1982) and subsequently assigned to Aragosaurus ( Sanz et al., 1987) came from a different locality, close to Las Zabacheras ( Sanz et al., 1987; Canudo et al., 2001). As such, its isolation, and the lack of a preserved tooth in the holotype, precludes its referral to Aragosaurus . It was described and illustrated by Sanz (1982) as being more similar to the teeth of Giraffatitan than Camarasaurus . In labial view, the crown shows no constriction at its base, contrasting with non-neosauropods ( Calvo, 1994; Upchurch, 1998), and it has a D-shaped cross section (with the greatest diameter oriented mesiodistally), differing from the cylindrical shape of diplodocoid and titanosaurian teeth ( Wilson & Sereno, 1998). The slenderness index (apicobasal length of the tooth crown divided by its maximum mesiodistal width; Upchurch, 1998) of the crown is 2.45, comparable with the values seen in basal titanosauriforms, but higher than observed in most non-neosauropods and Camarasaurus , and lower than diplodocoids and most titanosaurs ( Upchurch, 1998; Chure et al., 2010). The apical half of the lingual surface of the crown is concave between broad mesial (partly worn away) and distal ridges, although there is no lingual ridge. Serrations and denticles are absent. There is a V-shaped wear facet, contrasting with the planar wear facets present in diplodocoids and derived titanosauriforms ( Wilson & Sereno, 1998). This combination of features suggests that this tooth crown should be regarded as representing an indeterminate titanosauriform.

DESCRIPTION AND COMPARISONS

AXIAL SKELETON

Caudal vertebrae

Portions of 14 anterior to posterior caudal vertebrae are preserved: IG 453 (V8) = Cd1, IG 493 (V9s) = the spine of Cd1, IG 474 (V2s) = Cd2, IG 473 (V1) = Cd3, ZH-18 = Cd4, IG 450 bis (V5) = Cd5, ZH-17 = Cd6, IG 475 (V3) = Cd7, IG 476 (V4) = Cd8, IG 477 (V5) = Cd9, ZH- 15 = Cd10, IG 479 (V7) = Cd11, IG 480 (V8) = Cd12, ZH-12 = Cd13, ZH-16 = Cd14, IG 468 (V55, X3) = fragments of neural arches. Several vertebrae are relatively complete ( Fig. 4 ; Table 2). Although these do not

represent a continuous sequence, they are referred to here as Cd1–Cd14. Centra are amphicoelous/ amphiplatyan, with a concave anterior articular surface and a flat to gently concave posterior surface ( Sanz et al., 1987; Royo-Torres, 2009). This type of articulation, termed ‘planiconcave’ by Tidwell, Carpenter & Meyer (2001), whereby the depth of the concavity of the anterior surface is greater than that of the posterior surface, is a feature common to most sauropods lacking procoelous anterior caudal centra (D’Emic, 2012), including Camarasaurus , Brachiosaurus , and Sauroposeidon (= ‘ Paluxysaurus ’) ( D’Emic, 2013).

Anterior caudal vertebrae of Aragosaurus differ from the procoelous anterior caudal vertebrae of titanosaurs, flagellicaudatans, mamenchisaurids, and turiasaurs ( McIntosh, 1990; Upchurch, 1995, 1998; Royo-Torres et al., 2009; Mannion et al., 2013). All centra have a cylindrical cross section. Unlike many diplodocoids and titanosaurs ( McIntosh, 1990; Upchurch, 1995, 1998; Wilson, 2002; Upchurch et al., 2004a; Curry Rogers, 2005; Mannion & Barrett, 2013), the ventral surfaces lack a midline sulcus or ventrolateral ridges, although very weak ridges support the posterior chevron facets. Anterior chevron facets are relatively weakly developed, but posterior chevron facets are present on all of the preserved centra.

The lateral surface of the centrum merges smoothly into the ventral surface on the anteriormost caudal vertebrae, although this angle becomes slightly more abrupt further along the tail. There are no lateral pneumatic openings on the centra. The most anterior vertebrae bear a bulge on their lateroventral surface below the caudal rib ( Fig. 4 ), probably in Cd1–Cd3. This is a derived character state shared with Giraffatitan , Abydosaurus ( Chure et al., 2010) , Tastavinsaurus , and the titanosaur Andesaurus (D’Emic, 2012; Mannion et al., 2013). This feature is absent in Cd4 and subsequent caudal vertebrae. This feature differs from the moderately well-developed, anteroposteriorly orient- ed ridge that is present on Cd5–8 at approximately two-thirds of the way up the lateral surface of the centrum. This ridge divides the lateral surface into two parts: the more ventral surface is the primary and the more dorsal surface is the secondary (sensu Salgado & Coria, 2002). The caudal ribs are simple, dorsoventrally compressed, laterally projecting processes, differing from the strongly posterolaterally directed ribs of most titanosauriforms ( Mannion & Calvo, 2011; Mannion et al., 2013), but comparable with those of Brachiosaurus ( Taylor, 2009) . A prezygodiapophyseal lamina (PRDL) extends from the anterodorsal margin of the caudal rib ( Fig. 4 of IG 473 and 474), a feature that Aragosaurus shares with a number of basal titanosauriforms, e.g. Tastavinsaurus ( Canudo, Royo-Torres & Cuenca-Bescós, 2008) , Venenosaurus ( Tidwell et al., 2001) , Abydosaurus ( Chure et al., 2010) , Cd1–Cd14 is the ‘series’ shown in Figure 4 . All measurements are in millimetres.

Brachiosaurus , and Giraffatitan ( Wilson, 2002) , but that is also present in more basal eusauropods such as Mamenchisaurus ( Young & Zhao, 1972) , and most diplodocoids ( Wilson, 2002), including the putative basal form Haplocanthosaurus ( Hatcher, 1903).

The neural arches are slightly biased towards the anterior margin of the centrum, but this is not the strong anterior shift seen in most titanosauriforms ( Calvo & Salgado, 1995; Upchurch, 1995, 1998; Salgado et al., 1997), and middle caudal neural arches are situated on approximately the central half of the centrum ( Fig. 4 ). The neural canal is circular in the most anterior caudal vertebrae, and is wider dorsoventrally than transversely in the middle caudal vertebrae ( Sanz et al., 1987). Prezygapophyses project anterodorsally in the anteriormost caudal vertebrae (Cd4 and Cd6), but are directed mainly anteriorly in subsequent vertebrae. The flat prezygapophyseal articular surfaces face medially and slightly dorsally ( Sanz et al., 1987). As a consequence of poor preservation in the postzygapophyseal region, it is not possible to determine whether a hyposphenal ridge was present in any of the anterior caudal vertebrae. Postzygapophyses are unusual in the middle caudal vertebrae in that they project as short processes posterolaterally from the underside of the spine (Cd10, Fig. 4N and O ). These project beyond the posterior margin of the centrum but do not extend as far posteriorly as the tip of the spine. Some postzygapophyses also have epipophysis-like protuberances on their dorsal surfaces (Cd10, Fig. 4 ). This postzygapophyseal morphology is considered an autapomorphy of Aragosaurus .

A single intraprezygapophyseal lamina (with a rounded anterior margin) floors the prespinal fossa, and this fossa is bounded by well-developed, rounded spinoprezygapophyseal laminae (SPRLs). The SPRLS merge into the anterolateral margins of the spine and diverge laterally at their anterior ends. This prespinal fossa differs from that seen in the caudal vertebrae of Tastavinsaurus (MPZ99/9) in that it is not slotlike or closed at its anterior end. Spinopostzygapophyseal laminae (SPOLs) rapidly fade into the posterolateral margins of the spine, meaning that there is no postspinal fossa along the dorsal two-thirds of the spine (Cd4, Fig. 4 ). The base of the neural spine is almost square in cross section, but this is given the appearance of a more transversely compressed cross section by the presence of the SPRLs.

Neural spines project posterodorsally in the anteriormost caudal vertebrae, and are strongly directed posteriorly in middle caudal vertebrae. These caudal neural spine orientations represent the plesiomorphic condition, and thus differ from the derived anterodorsal orientation of the neural spines in some basal titanosauriforms such as Tastavinsaurus , Cedarosaurus , and Venenosaurus (D’Emic, 2012; Royo-Torres, Alcalá & Cobos, 2012). The ratio of the height of the neural spine to centrum height is 1.25 in anterior caudal vertebrae. Towards the dorsal end of the anteriormost neural spines (Cd1 and Cd4), the spine becomes slightly compressed anteroposteriorly and expands strongly transversely, giving the spine a club-shaped outline in anterior view, similar to the anterior caudal neural spines of Brachiosaurus , Camarasaurus , Losillasaurus , Lourinhasaurus , Tastavinsaurus , and Turiasaurus ( Casanovas, Santafé & Sanz, 2001; Canudo et al., 2008; Taylor, 2009; Mannion et al., 2013; Mocho, Royo-Torres & Ortega, 2014). As a result of this expansion, the dorsal surface of the spine is strongly convex transversely and forms rounded projections that slightly overhang the lateral surfaces (Cd1, Fig. 4 ). The anterior, posterior, and dorsal surfaces are strongly rugose, whereas the lateral surfaces of the neural spine are smooth. Shallow dorsolateral concavities are present on either side of the expanded summits of anterior caudal neural spines (Cd1 and Cd4, Fig. 4 ), a probable autapomorphy of Aragosaurus . Subsequent caudal neural spines are laterally compressed plates with only slightly expanded dorsal ends (Cd5, Fig. 4 ), whereas middle–posterior caudal neural spines have cylindrical cross sections and taper to a transversely thin, acute dorsal ridge (Cd10, Fig. 4 ).

Dorsal rib fragments

Seven dorsal rib fragments [IG 468 (V40), IG 481 (Cos), IG 487 (Phs1), IG 492 (Uls), V20] have been recovered, representing portions of the middle and distal shafts. All of them have a solid bone texture and only in two distal ribs is it possible to identify a distal rugose surface. One of them is probably an anterior rib, with a plank-like structure ( Fig. 5A–C ), a feature originally optimized as a titanosauriform character ( Wilson, 2002), and the second is a posterior rib ( Fig. 5D–F ).

Haemal arches

A total of eight anterior–middle chevrons are preserved (ZH-4, ZH-5, ZH-7, ZH-8, ZH-9, ZH-11, ZH- 13, ZH-14; Fig. 6 ; Table 3). All of them are open proximally, although in some cases (i.e. ZH-9) the proximal facets are very close ( Sanz et al., 1987). Proximally open chevrons represent a derived state that occurs in most macronarians, but are also found in Shunosaurus and rebbachisaurids ( Calvo & Salgado, 1995; Upchurch, 1998). Within Macronaria, several Chinese titanosauriforms ( Mannion & Calvo, 2011) and Camarasaurus lewisi ( McIntosh et al., 1996b) display proximally bridged chevrons, and it is possible that some (but not all) chevrons of Lusotitan are bridged (Mannion et al., 2013). The ratio of haemal canal depth to total chevron height varies along the tail: this ratio is approximately 50% in the second most anteriorly preserved chevron, but is only 29% in chevron ZH-4. Wilson (1999, 2002) and Curry Rogers & Forster (2001) noticed that titanosaurs typically possess chevrons in which the ratio of haemal canal height to total chevron length is 0.5, whereas in other dinosaurs (including basal eusauropods and diplodocoids) this ratio is typically 0.3 or lower. The observation that Aragosaurus displays the derived state in some specimens and the plesiomorphic state in others could indicate that the derived condition first evolved in more anterior chevrons, and then spread to middle chevrons later in titanosauriform evolution. If this interpretation is correct, All measurements are in millimetres.

Aragosaurus could be regarded as possessing an intermediate condition between the plesiomorphic and derived states.

The proximal articular surfaces of the haemal arches are flat, lacking the anteroposteriorly convex surfaces of several titanosauriforms ( Mannion & Calvo, 2011), including Tastavinsaurus ( Canudo et al., 2008) . The distal shafts of the two anteriormost preserved chevrons are anteroposteriorly compressed and slightly widened transversely, whereas from the third chevron onwards the distal shaft is transversely compressed. The most distally preserved chevron comes from a middle caudal vertebra, and is strongly curved in lateral view, with the distal shaft projecting backwards and downwards at an angle of approximately 45° to the horizontal. There is no anterior expansion of the shaft, suggesting that Aragosaurus lacked the ‘forked’ chevrons of most non-titanosauriforms ( Berman & McIntosh, 1978; Upchurch, 1995, 1998; Wilson & Sereno, 1998). The haemal arches are generally too incomplete for measurements to be taken, although two measurements were obtained from the near-complete ‘chevron 4’ ( Table 3).

PECTORAL GIRDLE AND FORELIMB

Scapula

This element is known from the nearly complete right scapula (ZH-1) and the distal end of the blade of the left scapula (IG 482) ( Fig. 7 ; Table 3). It will be described with the distal blade oriented horizontally, although in life it probably projected posterodorsally. The right scapula is well preserved, although it is missing portions from the anterodorsal part of the acromion and the dorsal margin of the distal end of the blade. This element is mounted with the medial surface exposed and the lateral surface accessible but facing a wall: consequently some aspects of the lateral surface are difficult to observe directly. The lateral surface of the acromion bears a well-developed acromial (‘deltoid’) ridge. Immediately posterior to this ridge, the lateral surface is shallowly concave as also occurs in most sauropods, except for basal forms (e.g. Shunosaurus ) and some titanosaurs (e.g. Alamosaurus and Opisthocoelicaudia ; Upchurch et al., 2004a; Harris, 2006). The angle between the acromial ridge and the blade appears to be close to 90° or slightly less. The stout glenoid region bears an articular surface that faces anteroventrally: thus, Aragosaurus possesses the plesiomorphic state rather than the derived medial deflection of the glenoid observed in somphospondylans and Apatosaurus ( Wilson & Sereno, 1998; Upchurch, Tomida & Barrett, 2004b). The distinct bulge or triangular ventromedial process close to the proximal end of the ventral margin of the blade observed in forms such as Chubutisaurus ( Carballido et al., 2011a) , Alamosaurus ( D’Emic, Wilson & Williamson, 2011) , and Lourinhasaurus (P.U. and P.D.M., pers. observ., 2009), cannot be observed in Aragosaurus , but this margin might have been damaged. In cross section, the base of the blade has a D-shaped profile, with a thinner dorsal margin and wider ventral margin: this is a derived state that occurs in most neosauropods, except for some derived titanosaurs such as Opisthocoelicaudia , where the cross section becomes subrectangular ( Wilson, 2002). No ridges or rugosities are present on the medial surface of the blade, unlike some advanced titanosaurs such as Lirainosaurus ( Sanz et al., 1999) . It appears that the scapular blade of Aragosaurus expanded in dorsoventral height near its distal end, but the exact degree of expansion cannot be determined because of poor preservation; however, it is unlikely that the dorsal margin was prominently expanded as in rebbachisaurids (see Sereno et al., 2007; Mannion, 2009).

Coracoid

The left coracoid (IG 482) ( Fig. 7 ; Table 3) will be described as if it were connected to a scapula, the distal blade of which is directed horizontally backwards (see above). Only the ventral half of the left coracoid is preserved. In lateral view, the anterior margin of the coracoid is gently convex dorsoventrally: this suggests that this margin and the dorsal margin might have merged smoothly into each other (as occurs in most nonneosauropod eusauropods; Upchurch, 1998; Upchurch et al., 2004a), but the specimen is not well enough preserved for this character state to be established with confidence. The lateral surface of the coracoid is mildly convex and, as in other sauropods, lacks the tubercle on its anteroventral part that occurs in more basal sauropodomorphs ( Upchurch, Barrett & Galton, 2007; Yates, 2007), and in the titanosaurs Lirainosaurus and Opisthocoelicaudia ( Borsuk-Bialynicka, 1977; Díez Díaz, Pereda Suberbiola & Sanz, 2013). The anteroventral portion of the coracoid forms a slightly acute projection that is emphasized by the mild upward concavity of the ventral margin that lies just posterior to this corner. This concave, notch-like area is small (when compared with the size of the glenoid) relative to those observed in other sauropods. The very stout glenoid region lies immediately posterior to this ventral notch. The rugose glenoid articular surface faces posteroventrally, and is not deflected to face medially. The glenoid forms the transversely widest part of the coracoid ( Table 3), largely because it expands prominently along its lateral edge to form a ‘lateral glenoid shelf’. The lateral margin of this glenoid ‘shelf’ curls upwards towards its edge, so that part of the rugose articular surface can be observed in lateral view. This feature is present in other neosauropods, e.g. Lourinhasaurus ( Mocho et al., 2014) , Camarasaurus grandis ( Ostrom & McIntosh, 1966: pl. 46), Brachiosaurus ( Riggs, 1903; 1904; Taylor, 2009), and Giraffatitan ( Janensch, 1961: fig. Abb.1ab; Taylor, 2009). Posteri- or to the glenoid, the lower part of the articulation for the scapula can be observed. This is a robust area (although not as wide transversely as the glenoid), and faced either posteriorly or posterodorsally. Only the smooth posteroventral margin of the coracoid foramen is preserved, indicating that this opening lies close to the scapulocoracoid junction. The medial surface of the coracoid is shallowly concave.

Humerus

The right humerus (IG 490; Fig. 8 , Table 3) appears to be nearly complete, but is preserved as separate proximal and distal halves. This bone was illustrated by Lapparent (1960), but was not described. The broken mid-shaft regions of each of these halves are nearly identical in terms of their cross-sectional shape and dimensions ( Table 3), suggesting that little material has been lost from this region ( Fig. 8 ). The medial portion of the proximal end is missing. In anterior view, the proximal articular surface and lateral margin of the humerus merge smoothly into each other to form a convex region: thus Aragosaurus retains the plesiomorphic state that occurs in most sauropods and lacks the derived ‘squared’ proximolateral corner observed in many somphospondylans ( Upchurch, 1999; Wilson, 2002; Upchurch et al., 2004a; Mannion et al., 2013). Also, unlike derived titanosaurs such as Saltasaurus and Opisthocoelicaudia ( Upchurch, 1998) , the proximolateral corner of the humerus of Aragosaurus lacks a rounded supracoracoideus projection. The proximal part of the deltopectoral crest is preserved, but the more distal (and presumably more prominent) section of this crest is missing. The deltopectoral crest projects mainly anteriorly, but is also deflected slightly laterally: as a result, the lateral surface of the proximal part of the crest is mildly concave. At approximately midlength, where the shaft is broken, the horizontal cross section has a suboval outline, with the long axis of this oval oriented transversely. This cross-sectional profile is formed by relatively straight anterior, rounded lateral and posterior, and acute medial margins. Compared with the overall size of the humerus, the crosssectional area of the mid-shaft is relatively small, with a transverse width of shaft at midlength/humerus length ratio of approximately 0.12 ( Table 3). Such gracile humeri (where the mid-shaft width/humerus length ratio is less than 0.15) also occur in some other sauropods, including the basal eusauropod Lapparentosaurus , several brachiosaurids, and the basal somphospondylan Ligabuesaurus ( Curry Rogers, 2005; D’Emic, 2012; Mannion et al., 2013). The distribution of gracile humeri suggests that this feature evolved several times among different sauropod lineages, and it therefore does not provide strong support for any particular identification of the affinities of Aragosaurus . The profile of the lateral margin of the humeral shaft is concave rather than the derived straight margin seen in some titanosaurs ( Curry Rogers, 2005). The humerus lacks a pronounced tuberosity for the muscle latissimus dorsi, unlike some derived titanosaurs ( Otero, 2010; D’Emic, 2012).

The distal half of the humerus is damaged along its lateral margin. As in other sauropods, the distal part of the anterior surface is mildly convex transversely and lacks the deep concavity observed in basal sauropodomorphs and other dinosaurs ( Upchurch et al., 2007; Yates, 2007). There are two small projections situated close to the midline, where the anterior surface meets the distal articular surface; as such, Aragosaurus retains the plesiomorphic state of a divided anterior condyle, differing from the condition in derived somphospondylans (D’Emic, 2012). The anteromedial part of the distal end is moderately expanded to form a rounded projection: as a result, the distal part of the medial surface faces posteromedially and is mildly convex. Posteriorly, there is a well-developed anconeal fossa that is defined medially and laterally by low rounded ridges that extend from the distal end and fade out proximally, but these are not the acute prominent ridges observed in many titanosaurs ( Upchurch et al., 2004a). The rugose distal articular surface does not curve up onto the anterior or posterior faces of the humeral shaft, unlike the derived condition that occurs in several titanosaurs ( Wilson & Carrano, 1999; Wilson, 2002).

The ratio between humerus and femur lengths is approximately 0.82 ( Sanz et al., 1987; Royo-Torres & Ruiz-Omeñaca, 1999), which is similar to most titanosauriforms (Mannion et al., 2013), as well as Lourinhasaurus ( Mocho et al., 2014) , but differs from the condition in brachiosaurids, whereby this ratio is closer to 1.0 ( Wilson, 2002). In Aragosaurus , this ratio is slightly higher than in other basal macronarians such as Camarasaurus (0.75; Madsen, McIntosh & Berdman, 1995; Ikejiri, 2005) and Tehuelchesaurus (0.72; Carballido et al., 2011b).

Ulna

The right ulna (IG 483; Fig. 9 ; Table 3) is nearly complete and resembles those of other sauropods in most respects. The proximal end is triradiate, formed by long anteromedial and anterolateral processes and a weakly developed posterior process. There is a deep fossa between the anteromedial and anterolateral processes, for reception of the proximal end of the radius. The anteromedial and anterolateral processes are subequal in length ( Table 3): this state also occurs in several other sauropods (e.g. Apatosaurus , Europasaurus , Malawisaurus , and Mamenchisaurus ), whereas the former process is much longer [e.g. Camarasaurus , Giraffatitan , and Sauroposeidon (‘ Paluxysaurus ’ material)] or even twice as long ( Cedarosaurus and Venenosaurus ) as the latter process in several macronarians (Mannion et al., 2013). The articular surface of the anteromedial process is flat longitudinally and slopes strongly anterodistally at an angle of approximately 45° to the horizontal. A similar, potentially derived, condition occurs in the basal macronarian sauropod Lusotitan (Mannion et al., 2013) . In contrast, the articular surface of the anterolateral process is flat longitudinally and moderately convex transversely.

On the anterior surface of the shaft, there is a strong interosseous ridge that first appears on the proximal half of the ulna, increases in prominence distally, and finally disappears about 100 mm above the distal end. Such a ridge is common in other sauropods and probably represents the attachment site of ligaments that bound the ulna and radius together; however, this ridge is normally restricted to the distal part of the ulna, except in several titanosaurs where this structure can occupy most of the length of the element ( Curry Rogers, 2005, 2009; see ‘Radius’ below for further discussion of this feature). Below the end of this ridge there is a triangular striated concavity. Although the distal end of the ulna is expanded relative to the shaft, this expansion does not seem to be particularly marked relative to that observed in most sauropods. The outline of the distal end is between elliptical and subcircular.

Radius

The right radius is complete (IG 484; Fig. 9 ; Table 3). The proximal articular surface is flat and has a suboval outline, with the long axis of this oval oriented mediolaterally. This element is relatively slender (proximal transverse width/radius length ratio = 0.22; Table 3), as in most sauropods: thus Aragosaurus lacks the apomorphically robust radius observed in many titanosaurs, where the proximal transverse width is often more than 30% of the radius length ( McIntosh, 1990; Upchurch, 1995, 1998). In lateral view, the radial shaft is bowed slightly anteriorly. On the lateral part of the posterior surface, a well-developed ridge extends from the proximal end to approximately one-third of the radius length from the distal end, increasing in prominence distally, and corresponding with the ridge described on the anterior face of the ulna (see above). This ridge on the posterior face of the radius terminates in a rounded eminence or tubercle at a point approximately 25% of the shaft length from the distal end of the radius. Curry Rogers (2005: character 283) noted the presence of a well-developed interosseous ridge as a derived state in many titanosaurs (e.g. Aeolosaurus , Ampelosaurus , Neuquensaurus , Opisthocoelicaudia , and Rapetosaurus ). In at least some of these taxa (e.g. Opisthocoelicaudia, Borsuk-Bialynicka, 1977 : fig. 8C; Rapetosaurus, Curry Rogers, 2009 : fig. 36D), the interosseous ridges extend along most of the length of both the ulna and radius, as occurs in Aragosaurus . As Aragosaurus is probably a basal macronarian (see below) that is not closely related to such derived titanosaurs, the elongated interosseous ridge is here provisionally considered to be a local autapomorphy. The tubercle at the distal end of this ridge is also potentially unique to Aragosaurus .

The distal end has a subrectangular outline, similar to most sauropods ( Wilson & Sereno, 1998), although the posterior margin has a slightly concave profile. The distal articular surface is rugose and strongly convex and, in anterior view, slopes proximally towards its lateral margin at an angle of 16–17° to the horizontal. This ‘bevelling’ of the lateral half of the distal articular surface occurs in a wide array of eusauropods (Mannion et al., 2013), although it is more prominently developed and continuous across the distal surface in derived titanosaurs such as Opisthocoelicaudia and Saltasaurus ( Wilson, 2002; Mannion et al., 2013; Mateus, Mannion & Upchurch, in press).

Carpal

A single block-like carpal element is preserved (IG 485; Fig. 10 ; Table 3). It is similar to the carpal bone (cat. no. 445) of Camarasaurus grandis (GMNH-PV 101) that was described as a ‘radiale’ by McIntosh et al. (1996a). Given that the other forelimb and manual elements of Aragosaurus are all preserved from the right side, for the purposes of description it will be assumed that the carpal also belongs to the right manus. This element is subquadrangular in proximal and distal views, with rounded corners. The proximal articular surface is mildly concave, as is also seen in the carpals of Camarasaurus ( McIntosh et al., 1996a) , Turiasaurus , and Losillasaurus (R.R.T., P.U., and P.D.M., pers. observ. 2009). In contrast, the distal surface is mildly rugose and possesses only a mild projection on its posterolateral part, unlike Turiasaurus , where this projection is much more prominent ( Royo-Torres et al., 2006). The Aragosaurus carpal also lacks the less prominent projection that occurs on the posteromedial part of the distal surface in Turiasaurus . Neither the proximal nor distal articular surfaces are divided into two or more separate regions by an anteroposteriorly oriented ridge, differing from the proximal surface of the ‘scapholunar’ carpal described in Apatosaurus by Hatcher (1902: 367). In Aragosaurus , the anterior, posterior, lateral, and medial margins are generally proximodistally rounded, except at the posterolateral corner, where the carpal has its greatest proximodistal thickness. Here, the posterior part of the lateral surface is mildly concave, partly as a result of a slight outwards projection of the distal rim. This element maintains approximately the same proximodistal thickness over virtually all of its extent: thus the bone does not thin towards one or more of its edges, unlike the ‘scapho-lunar’ of Apatosaurus , where the anterior margin is much thinner than the posterior margin ( Hatcher, 1902). The subquadrangular proximal outline of the carpal of Aragosaurus is potentially autapomorphic because the carpals of other sauropods are typically circular or elliptical (e.g. Turiasaurus and Losillasaurus, Royo-Torres et al., 2006 ; Apatosaurus, Hatcher, 1902 ; Ostrom & McIntosh, 1966: pl. 54; and Camarasaurus, McIntosh et al., 1996a ).

Metacarpus

Portions of four metacarpals (I, II, III, and IV) from the right manus are preserved [IG 486 (rmc1), IG 486 (rmc2), IG 486 (rmc3), and IG 486 (rmc4); Figs 11 and 12 ; Table 3]. In the following description, the orientations of these elements are based on the Camarasaurus manus ( Ostrom & McIntosh, 1966; McIntosh et al., 1996a). In life, the metacarpals would have formed a U-shaped arrangement with the long axes of their shafts extending vertically, as in other eusauropods ( McIntosh, 1990; Upchurch, 1998; Upchurch et al., 2004a); however, for the purposes of description, the metacarpals are treated as though they lie side-by-side with their long axes extending forwards and the long axis of the distal end of each metacarpal oriented transversely.

The articular surface of the right metacarpal I [IG 486 (rmc1); Fig. 11 ; Table 3], in proximal view, has a trans- versely compressed D-shaped outline, with rounded dorsal and medial margins, and flat and concave ventral and lateral margins ( Fig. 11 ). The proximal outline is similar to metacarpal I of Giraffatitan ( Janensch, 1961) , and differs from the more circular outline of Camarasaurus ( Ostrom & McIntosh, 1966; McIntosh et al., 1996a). The proximal half of the lateral surface forms a subtriangular and longitudinally striated concavity that extends along the shaft of the metacarpal to approximately midlength. Just distal to midlength, the shaft has an elliptical cross section, with the long axis of this ellipse oriented transversely. There is a ventrolaterally facing longitudinal groove on this central region of the shaft, which is bounded by a distal ridge along the lateral margin. The dorsolateral margin of the shaft also forms a relatively acute ridge. In Aragosaurus the distal end of metacarpal I terminates in two prominent condyles that are separated along their midline by a wide groove. The medial condyle is larger than the lateral one, mainly because it projects further ventrally. In distal end view, these condyles appear to slant ventrally and slightly medially. There is a shallow pit on the lateral surface of the distal condyle below the distal ridge on the lateral margin. The medial surface of the distal condyle is flat and striated.

In the right metacarpal II [IG 486 (rmc2); Fig. 12 ; Table 3], the proximal end is between subtriangular and D-shaped in outline, with a concave area on the proximal part of the lateral surface for articulation with metacarpal III, and a convex margin (with a slight proximodistal ridge) forming the medial area for articulation with metacarpal I. In general, the dorsal and medial surfaces are convex transversely and smooth, whereas the palmar area is flat and rugose. The shaft is triangular in transverse cross section and the distal end has two condyles separated by a groove. These condyles are most strongly developed on the palmar surface. The medial distal condyle is more prominent than the lateral one, but the lateral distal condyle projects further distally than the medial one. The distal articular surface does not appear to extend onto the dorsal surface of the metacarpal, a feature that Aragosaurus shares with most titanosauriforms (D’Emic, 2012). This metacarpal is at least 37% of the radius length ( Table 3), and almost certainly much greater because of missing material: this suggests that Aragosaurus possessed the derived state (longest metacarpal/radius length ratio of 0.45 or greater) that occurs in most macronarians ( Wilson & Sereno, 1998). Metacarpal II of Aragosaurus is different from those in Turiasaurus ( Royo-Torres et al., 2006) , and is similar to the metacarpal of Camarasaurus grandis ( McIntosh et al., 1996a) , because Aragosaurus and C. grandis ( McIntosh et al., 1996a) have two distinct distal condyles in palmar view where the articular surfaces of the distal ends curve down onto the palmar surface, whereas in Turiasaurus this surface is flat and distinct condyles are absent.

Fragmentary remains of right metacarpal III [IG 486 (rmc3); Table 3] and right metacarpal IV [IG 486 (rmc4); Table 3] are preserved. The distal end of metacarpal III has two distinct condyles similar to MC II. The proximal end of metacarpal IV is triangular in outline, lacking the ‘chevron’ profile seen in many titanosauriforms (D’Emic, 2012; Mannion et al., 2013).

PELVIC GIRDLE AND HINDLIMBS

Right pubis

Most of the right pubis is preserved [IG 489; Fig. 13 ; Table 4); however, much of the symphyseal margin (below the ischial articulation) is missing and has been restored, and the obturator foramen is also not preserved in this portion. Royo-Torres et al. (1999) initially identified a separate portion of bone (IG 488) as part of the pubis, but here it is reinterpreted as the pubic peduncle of the left ischium. The articular surface for the ilium is flat and strongly rugose. This articulation has a D-shaped outline in dorsal view, with the convex margin facing anteriorly and laterally. This articular area therefore lacks the extreme transverse compression seen in some titanosaurs (e.g. Andesaurus ; Mannion & Calvo, 2011). Immediately below the iliac articulation, the anterior surface of the pubis forms a broad, slightly flattened triangular area that tapers to a point ventrally (Royo-Torres et al., 1999). This ventral tip extends forwards as a low, rounded projection. Thus, the ambiens process of Aragosaurus resembles those of other sauropods in most respects, especially those of Lourinhasaurus (Royo-Torres, 2009) , Giraffatitan ( Janensch, 1961) , and possibly Haplocanthosaurus ( Rauhut et al., 2005), but there is no prominent hooked ambiens process like the pubes of several flagellicaudatans (e.g. Diplodocus , Barosaurus , and Dicraeosaurus ; McIntosh, 1990; Upchurch et al., 2004a, b). The Aragosaurus pubis resembles those of derived eusauropods, with a broad distal shaft that probably met its partner on the midline along an embayed symphysis (i.e. the anterolateral margins of each pubis lie in front of the plane of the symphysis, and so form a V-shape in horizontal cross section; see Upchurch, 1995; Harris, 2006). The distal end of the pubis is expanded, especially medially. There is a flattened area on the posteromedial surface of the distal end: this probably met a similar area on the left pubis to form a strong ventral end to the midline symphysis. As in most other sauropods, the distal end surface is strongly convex and rugose. The distal end of the pubis is expanded anteriorly, with the anterior margin of the very distal end forming an acute angle with the remainder of the anterior margin, similar to that seen in Camarasaurus ( Ostrom & McIntosh, 1966) , but differing from the rounded ‘boot’-like process that occurs in some titanosauriforms, e.g. Giraffatitan and Tastavinsaurus ( Canudo et al., 2008; Mannion et al., 2013).

Ischium

The ischium is represented by the nearly complete right element (ZH-3), the separate iliac peduncle and distal end of the shaft (IG 492), and a fragment of the pubic peduncle (IG 488) of the left element ( Fig. 14 ; Table 4). There is some reconstruction in the ventral region of ZH-3, where the blade meets the proximal expansion, and at the ventral tip of the pubic articulation. The length of the ischium is a little shorter than the pubis (the ischium/pubis length ratio is 0.9). This value is thus close to 1.0, as occurs in basal macronarians such as Camarasaurus grandis (ratio = 1.07; McIntosh et al., 1996a), Camarasaurus lentus (ratio = 0.98; Gilmore, 1925; Royo-Torres, 2009), Lourinhasaurus (ratio = 0.9–1.0; Mocho et al., 2014), and basal titanosauriforms, such as Giraffatitan (ratio = 1.0; Janensch, 1961). In more derived Titanosauriformes, the typical condition is to have an ischium that is somewhat shorter than the pubis, with a ratio of less than 0.9 (e.g. Tastavinsaurus , Isisaurus , Opisthocoelicaudia , and Saltasaurus ; Calvo & Salgado, 1995; Salgado et al., 1997; Upchurch, 1998; Upchurch et al., 2004a; Canudo et al., 2008; Royo-Torres, 2009; Mannion et al., 2013). The proximal expansion of the ischium resembles those of most other sauropods in having mildly dorsoventrally convex and concave lateral and medial surfaces, respectively, posterior to the pubic articulation. The latter is transversely widest at its dorsal (acetabular) end, and tapers ventrally. The iliac peduncle is widest anteroposteriorly at its base and narrows slightly towards its articular surface: thus, Aragosaurus lacks the distinct ‘neck’ observed in the ischia of several rebbachisaurids ( Sereno et al., 2007) and some derived titanosaurs (e.g. Muyelensaurus ; Mannion & Calvo, 2011). There is no tubercle on the lateral All measurements are in millimetres.

surface of the iliac peduncle, unlike the ischia of the titanosaurs Gondwanatitan and Opisthocoelicaudia ( Borsuk-Bialynicka, 1977; Kellner & de Azevedo, 1999; Upchurch et al., 2004a). The acetabular surface curves smoothly into the lateral surface of the proximal expansion, whereas the medial margin of the acetabulum meets the medial surface of the ischial plate at an abrupt ridge-like edge ( Sanz et al., 1987), contrasting with taxa such as Giraffatitan and Tastavinsaurus , which have a shallower acetabulum ( Sanz et al., 1987; Canudo et al., 2008; Royo-Torres, 2009). The acetabular surface does not display the morphology observed in several rebbachisaurids (e.g. Demandasaurus ; Mannion et al., 2012), in which it is transversely wide at the dorsal end of the iliac peduncle and pubic peduncle, but very narrow in its central portion.

The ischium has a dorsoventrally long pubic peduncle in relation to the element’s total length ( Sanz et al., 1987). This character can be quantified by the next ratio: the distance from the upper corner of the pubic blade up to the posterior margin of the element, to the dorsoventral length of the pubic articular surface ( Salgado et al., 1997: fig. 5). The derived state, characterizing Camarasauromorpha (sensu Salgado et al., 1997), Macronaria ( Wilson & Sereno, 1998), and Apatosaurus (Royo-Torres, 2009) , occurs when the distance from the upper corner of the pubic blade of the ischium to the posterior border of the bone is shorter than the pubic articulation. In Aragosaurus the distal blade is well developed, and the morphology of the midline symphysis of the distal blade suggests that there would have been a V-shaped notch between the left and right ischia in dorsal view when these elements were articulated in life. Consequently, Aragosaurus is likely to have possessed the plesiomorphic style of ischiadic symphysis observed in most sauropods, rather than the derived condition seen in titanosaurs such as Alamosaurus , Andesaurus , and Opisthocoelicaudia , in which the ventral emargination is absent and the midline symphysis extends forwards to the ventral end of the pubic articulation ( McIntosh, 1990; Upchurch, 1998; Wilson, 2002). The distal shaft is directed mainly posteriorly and only slightly ventrally: when the long axis of the distal shaft is projected forwards, it passes through the centre of the pubic articulation, contrasting with the derived condition that occurs in Giraffatitan ( Janensch, 1961) and Lapparentosaurus ( Upchurch, 1995) , where the shaft is directed strongly downwards. The distal ends of the ischia are subtriangular in outline and form a V-shaped arrangement in distal end view. Thus, Aragosaurus retains the plesiomorphic state that occurs in basal sauropods (e.g. Vulcanodon, Cooper, 1984 ; ‘ Bothriospondylus madagascariensis ’, Mannion, 2010 ) and flagellicaudatans, rather than the derived copla- nar arrangement that occurs in Haplocanthosaurus, rebbachisaurids, and most macronarians ( Upchurch, 1998: fig. 16; Wilson & Sereno, 1998).

Femur

The left femur is complete (ZH-2; Fig. 15 ; Table 4). This element displays most of the features that are typical in sauropod femora, including a dorsomedially direct- ed proximal articular head, absence of the lesser trochanter, a shaft that is straight in both lateral and anterior views, and well-developed distal condyles ( McIntosh, 1990; Upchurch, 1995, 1998; Wilson, 2002; Upchurch et al., 2004a, 2007). There is no ‘neck’ or constriction between the proximal articular head and the greater trochanter. The articular surface of the greater trochanter, at its lateral end, curves convexly onto a posteriorly projecting, low, rounded bulge, forming a trochanteric shelf. A similar morphology has been reported in several rebbachisaurids ( Sereno et al., 2007) and titanosaurs ( Otero, 2010; Mannion et al., 2013). In anterior view, the lateral margin of the proximal end is deflected medially relative to that of the shaft, with the long axis of the diaphysis deflected 6° from vertical ( Fig. 15 ), and just below the level of the greater trochanter there is a lateral ‘bulge’. This combined morphology characterizes most macronarians, although the medial deflection is lost in some derived titanosaurs (Royo-Torres, 2009; Royo-Torres et al., 2012; Mannion et al., 2013). This 6° angle also occurs in Tastavinsaurus and Lourinhasaurus (Royo-Torres, 2009; Royo-Torres et al., 2012), so these Iberian taxa might have an intermediate state, with a more derived state represented by an angle of at least 10° in titanosaurs ( Wilson & Carrano, 1999; Wilson, 2002).

As in most other eusauropods, the fourth trochanter of Aragosaurus is a low rounded ridge that is situated on the posteromedial margin of the shaft at approximately midlength, and is not visible in anterior view. Just anterior to the fourth trochanter, there is a shallow concavity on the medial surface of the shaft. At midlength, the femoral shaft is strongly compressed anteroposteriorly (transverse width/ anteroposterior width ratio = 1.96). Wilson & Carrano (1999) noted that the femoral shafts of titanosaurs tend to be more compressed anteroposteriorly than those of other sauropods, and Wilson (2002) defined the derived condition as a transverse width/anteroposterior width ratio of greater than 1.85, although several more basal taxa (e.g. Brachiosaurus , Giraffatitan , and Ligabuesaurus ) also possess the derived state (D’Emic, 2012; Mannion et al., 2013). The distal condyle for articulation with the fibula bears a well-developed vertical groove on its posterolateral margin, as occurs in other sauropodomorphs and most other dinosaurs. The intercondylar groove is well developed, especially on the posterior surface of the femur. The distal articular surface curves up onto both the posterior and anterior faces of the condyles: the latter feature is a derived condition that occurs in many titanosaurs ( Wilson & Carrano, 1999) and Diplodocus ( Wilson, 2002) .

Pedal phalanges

The pedal phalanx ZH-10 most closely resembles the left pedal phalanges II-1 and III-1 of other sauropods, although III-1 is usually slightly longer than wide in dorsal view ( Upchurch, 1993), and so we consider ZH-10 to be phalanx II-1 ( Fig. 16 ; Table 4). It is subrectangular in dorsal view, with the medial distal condyle projecting slightly further distally than the lateral distal condyle ( Sanz et al., 1987). This element is unusual in that it possesses a subtriangular transverse cross section at its midlength, with a dorsally directed apex, convex lateral and medial surfaces, and a mildly concave ventral (plantar) surface. The presence of the midline dorsal apex is provisionally regarded as an autapomorphy of Aragosaurus .

Pedal phalanx ZH-6 is only partially preserved and yields little anatomical data. This element was described by Sanz et al. (1987) as a bone with numerous faces for articulation.

ZH-19 is a typical, recurved eusauropod ungual claw that probably belongs to digit II of the right pes ( Fig. 16 ; Table 4). It is laterally compressed throughout its length, as occurs in other eusauropods ( Wilson & Sereno, 1998; Upchurch et al., 2007; Yates, 2007). The proximal articular surface lies in a plane that is slightly oblique to the long axis of the ungual, so that in life the claw would have been directed forwards and slightly laterally. In dorsal view, the ungual also curves slightly laterally towards its distal tip. The medial surface of the ungual is more convex dorsoventrally than is the lateral surface. The ventromedial margin, in its distal part, is slightly bulbous but does not form the tuberosities seen in many titanosauriforms (Mannion et al., 2013), including Gobititan (IVPP 12579; P.U. and P.D.M., pers. observ. 2007) and Tastavinsaurus (MPZ 99/9; P.U. and P.D.M., pers. observ. 2009). The ungual has a smooth lateral groove that is less deep than in Tastavinsaurus . This feature has also been observed in a possible second ungual phalanx from Galve (MPG CA-1). It is a part of historic material from the Villar del Arzobispo Formation according to Sánchez-Hernández (2005), and this phalanx appears in photographs of the elements of Aragosaurus taken by J.L.S. in the 1980s. This second ungual element could therefore be from Las Zabacheras, but it was never mentioned in the lists of bones from this locality ( Lapparent, 1960; Sanz et al., 1987).

Figures

Figure 4. Caudal vertebrae of Aragosaurus ischiaticus: A, the series of caudals in their relative positions from Cd1 to Cd14 in lateral view; B, C fragment (IG 453, Cd1) of anterior caudal vertebral centrum in anterior (B) and posterior (C) views; D, E, fragment (IG 474, Cd2) of anterior caudal vertebral centrum in lateral (D) and posterior (E) views; F, anterior caudal vertebral centrum (IG 473, Cd3) in anterior view from Lapparent (1960); G–I, anterior caudal vertebra (ZH- 18, Cd4) in left lateral (G), right lateral (H), and anterior (I) views; J–L, anterior caudal neural spine (IG 493, Cd1) in posterior (J), anterior (K), and lateral (L) views; LL, M, middle caudal vertebra (ZH-17, Cd 6) in left lateral (LL) and anterior (M) views; N, anterior caudal neural spine (IG 493, Cd1) in dorsal view; O, P, posterior caudal vertebra (ZH-15, Cd 10) in left lateral (O) and posterior (P) views; Q, distal caudal vertebrae (ZH-12 and 16, Cd 13 and 14) in left lateral view. Arrow 1: a bulge on the lateroventral surface below the caudal rib. Arrow 2: anterior caudal vertebrae possess neural spine summits with shallow, dorsolaterally facing concavities on either side of the midline. Arrow 3: small epipophysislike protuberances on the dorsal surfaces of middle caudal vertebral postzygapophyses.

Figure 5. Dorsal ribs of Aragosaurus ischiaticus: A–D, anterior dorsal distal rib (IG 492 Uls) in lateral (A), posterior (B), medial (C), and distal (D) views; E–H, posterior dorsal distal rib (IG 481) in medial (E), posterior (F), lateral (G), and distal (H) views.

Figure 6. Haemal arches of Aragosaurus ischiaticus: A, B, anterior chevron (ZH-4) in posterior (A) and anterior (B) views; C, D, anterior chevron (ZH-5) in anterior (C) and posterior (D) views; E, anterior chevron (ZH-7) in lateral view; F, G, middle chevron (ZH-9) in anterior (F) and lateral (G) views; H, posterior chevron (ZH-14) in lateral view.

Figure 7. Pectoral girdle elements of Aragosaurus ischiaticus: A–D, left coracoid (IG 482) in lateral (A), ventral (B), medial (C), and anterior (D) views; E, right scapula (ZH-1) in medial view and partial left coracoid in lateral view; F, anatomical articulation between the coracoid and scapula in lateral view.

Figure 8. Right humerus (IG 490) of Aragosaurus ischiaticus: A, humerus (in three portions) in anterior view; B, picture of the humerus, after Lapparent (1960), in anterior view; C, proximal portion in posterior view; D, proximal portion in lateral view.

Figure 9. Right ulna (IG 483) of Aragosaurus ischiaticus in: A, posterior, B, ventral, C, anteromedial, and D, medial views. Right radius (IG 484) of Aragosaurus ischiaticus in: E, anterior, and F, posterior views.

Figure 10. Right carpal (IG 485) of Aragosaurus ischiaticus in: A, anterior, B, posterior, C, medial, D, lateral, E, ventral, and F, dorsal views. Comparison between different carpals: G, Aragosaurus; H, Turiasaurus; and I, Losillasaurus.

Figure 11. Right metacarpal I (IG 486, rmc1) of Aragosaurus ischiaticus in: A, lateral; B, dorsal; C, ventral; D, distal; E, medial; and F, proximal views.

Figure 12. Right metacarpal II (IG 486, rmc2) of Aragosaurus ischiaticus in: A, proximal; B, medial; C, dorsal; D, ventral; E, distal; and F, lateral views.

Figure 13. Right pubis (IG 489) of Aragosaurus ischiaticus in: A, medial; B, anterior; C, lateral; D, dorsal; E, ventral; and F, posterior views.

Figure 14. Right ischium (ZH-3) of Aragosaurus ischiaticus in: A, posterior; B, lateral views. Fragments of the left ischium (IG 492) of Aragosaurus ischiaticus: C, D, pubic peduncle in anterior (C) and lateral (D) views; E, F, iliac peduncle in dorsal (E) and lateral (F) views.

Figure 15. Left femur (ZH-2) of Aragosaurus ischiaticus in: A, posterior; B, medial; and C, anterior views. Features observed in the femur: D, lateral bulge; E, head deflected medially; and F, bevelling of the distal end of the femur relative to the long axis of the shaft.

Figure 16. Right pedal elements of Aragosaurus ischiaticus: A, ungual phalanx II (ZH-19) in dorsal view; B, ungual phalanx II (ZH-19) and proximal phalanx (ZH-10) in medial views; C, ungual phalanx II in lateral view.