Vallès-penedès localities.

The Vallès-Penedès Basin (Catalonia, Spain) is a half-graben that originated as a result of the extensional tectonics that started by the earliest Neogene in the Western Mediterranean, due to the northward movement of the African plate [21–24]. The sedimentary sequences of this basin cover most of the Miocene [25], mainly corresponding to alluvial fan sediments, although some marine and transitional sequences were deposited during the early and middle Miocene. Sedimentation continued throughout the middle and late Miocene, resulting in a considerable sediment thickness due to continuous subsidence, particularly near to the main active fault, located in the NW margin of the basin.

The Vallès-Penedès Basin has delivered a rich fossil record of terrestrial vertebrates from the early to the late Miocene [26,27]. The ACM series [20,28–30] is situated in the area of els Hostalets de Pierola, which is characterized by thick middle to late Miocene alluvial sequences that correspond to the Upper Continental Complex of the basin [25,31]. The middle Miocene sequences of els Hostalets mainly consist in red to brown mudstones, sandstones, breccias and conglomerates, which were deposited in the distal-to-marginal, inter-fan zones of the coalescing alluvial fan systems of els Hostalets de Pierola and Olesa [20,29,32]. Such depositional environment would have favored the preservation of vertebrate remains in a mudstone-dominated sedimentary environment, thanks to the combination of high rates of subsidence and sediment supply [32]. The exact stratigraphic position of classical localities from els Hostalets [33,34] is unknown in many instances, having traditionally been grouped into Hostalets Inferior (Aragonian levels) and Hostalets Superior (Vallesian levels) [31,33–35]. This contrasts with the situation for the 250 m-thick ACM series, where more than 200 fossil vertebrate localities have been formally defined [20]. The age of these localities and many isolated finds can be accurately estimated on the basis of firm litho-, bio- and magnetostratigraphic correlation (for the last update, see Table S2 in [20]). The whole ACM series corresponds to the late Aragonian (middle Miocene), and from a biostratigraphic viewpoint it can be correlated to the late portion of MN6 and most the MN7+8 [20,36]). On the basis of magnetostratigraphic correlation [20,32,37]), the ACM series spans from ca. 12.6 to 11.4 Ma, and estimated interpolated ages for the several localities can be provided on the basis of average local sedimentation rates for each subchron [20]. The material described here comes from ACM localities C2-A3, C3-A6, C3-A7 and C4-C2. C3-A7 and C2-A3 are the oldest localities (the former being stratigraphically 5 m below the latter), with an interpolated estimated age of 12.0 Ma within C5r.3r; C3-A6 and C4-C2 are slightly younger, being stratigraphically situated several meters above C2-A3 (10 and 20 m, respectively), with an interpolated estimated age of 11.9 Ma, also within C5r.3r. All these localities are correlated to the Megacricetodon crusafonti + Democricetodon crusafonti Interval Subzone of the Vallès-Penedès Basin [20,36]), representing the earlier portion of MN7+8.

Cerro de los Batallones.

Cerro de los Batallones (Torrejón de Velasco, Madrid Basin) includes a set (BAT-1 to BAT-10) of exceptionally rich paleontological sites of Vallesian age (ca. 10–9 Ma, MN10, late Miocene; [38–41]. These sites are situated on the top of the Intermediate Miocene Unit of the Madrid Basin, and are probably synchronous with or even posterior to the deposition of the upper Miocene Unit of the above-mentioned basin. BAT-1 was discovered during the industrial exploitation of sepiolite deposits [38,40,42], which are interpreted as a result of neoformative and transformational processes of fine sediments in a lacustrine margin, due to periodical episodes of lowering of the water level and subaerial exposition [40]. Sedimentological evidence suggests that sepiolite deposits were formed in a lacustrine-palustrine depositional context, whereas fossil remains were accumulated in holes, formed due to pseudokarstic processes (piping), that acted as natural traps [39–41,43] (see [44] for further details on the taphonomy of Batallones). The Varanus material described in this paper comes from BAT-3, which on the basis of micromammalian remains [45] is probably somewhat younger than BAT-1, although being also correlated to MN10.

Remarks.

The name Varanus marathonensis was introduced in the literature by Weithofer in 1888 [15]. He described (on pages 291–292) and figured (in plate 19 in figs. 8–9 in [15]) two fossils from Pikermi (Fig 1A and 1B) without designating a holotype: a slab hosting what he considered to be a premaxilla, a maxilla, and a prefrontal; and an isolated supraorbital. Of these syntypes, only the slab is still available (IPUW 1888-001-001), and its direct examination allowed us to confirm with confidence the identity of the maxilla but not of the premaxilla and the prefrontal. Here we select this specimen as the lectotype of the species, whereas the supraorbital (whose current whereabouts is unknown) would become a paralectotype. It is worth mentioning that Weithofer himself remarked that a monitor lizard from Pikermi was previously reported by Gaudry in 1862 ([49] and figured in table 60, figs. 3 and 4; here shown in Fig 1C and 1D) without erecting any new species but simply writing “Varanus? Vertèbre qui ressemble à celles des grands varans de l’Afrique”. Such vertebra is still available in the collections of the Muséum national d'Histoire naturelle (Paris, France) with the accession number “MNHN Pikermi n. 31”. Fejérváry [50] correctly considered the material described by Weithofer as “type-remains” (see caption of his text fig. 8 in [50]) but other authors apparently overlooked the original paper by Weithofer and considered Gaudry’s vertebra as the holotype of V. marathonensis [7] or refigured it (without explicitly considering it as type material) while discussing V. marathonensis [9]. More recently, Conrad et al. [11] erroneously considered Gaudry’s vertebra as the “original holotype” of V. marathonensis and “treated the partial skull separate from the presumed holotypic vertebra because there is no clear reason to associate them”.

Description of the type material from Pikermi.

IPUW 1888-001-001 is a left incomplete maxilla, 39.80 mm long, preserved on a block of hardened reddish sediment along with a few other unidentified bone fragments (Fig 1). The maxilla shows only the external and, partially, dorsal surfaces. The anterior portion of the maxilla is partly covered by an unidentified bone laying over it. The dorsal tip of the pars facialis and the posterior maxillary process are broken off. The general preservation is rather poor: the bone appears to be significantly mediolaterally compressed; the external surface of the maxilla is missing for about 8 mm at the level of the posterior end of the crista transversalis (a damage also visible in the original drawing by Weithofer [15]; fig 19:8); the lateral surface of the pars facialis and the area below it are severely fractured and the fragments have been apparently glued together so that a yellowish film covers most of the bone. Noteworthy is that in the above-mentioned figure accompanying the original description, these fractures appear like dendroid root traces that are actually absent (compare Fig 1A with Fig 1E). The anterior portion of the maxilla is slightly rotated in dorsal direction. Even if not perfectly preserved, the maxilla shows relevant morphologic characters. The crista transversalis is significantly raised in a dorsal direction (this could be partially due to mediolateral compression). The facial process is raised in the posterior section of the maxilla and its anterodorsal surface gradually slopes in dorsal direction. The anterodorsal sloping surface of the facial process is mediolaterally wide and hosts a deep concavity that is medially expanded. The surface of this concavity is not covered by the yellowish varnish film that covers most of the bone, but it is grayish in color, as the areas of the bones where the film was had been lost, and contrasts with the surrounding reddish matrix. The rims of the concavity are rather close to each other, probably due to compression (Fig 1F). The depth of the depression could be related to compression, but it is also possible that it was slightly excavated during preparation. In dorsal view, the medial edge of the maxilla, in the region between the crista transversalis and the medial expansion of the ascending margin of the processus facialis, is markedly concave. There is no trace of a lateral groove in the anterior sector of the narial opening (see below the section concerning the Iberian remains), probably because of the poor preservation of the bone. Due to incompleteness and breakage of the surface of the maxilla, the lateral foramina are not visible with the exception of a single foramen located close to the ventral edge of the maxilla, approximately in the middle of the preserved portion of the bone (Fig 1E). Four teeth are partly preserved along with the imprints of two additional teeth (the last one may host a tooth fragment). Teeth are triangular and pointed, but they only minimally preserve the original surface (an exception is represented by the apex of the first and third preserved teeth) so that the fine dental morphology (features such as basal wrinkles, denticles on the distal keel of the tooth, structure of the plicidentine) is no longer visible.

Weithofer [15] also described the presence of the premaxilla and prefrontal but the other bones hosted on the same block cannot be identified with confidence and therefore cannot be referred to a monitor lizard. The ‘supraciliare’ (= supraorbital) discussed and figured by Weithofer ([15], fig. 19:9) was not found. Based on Weithofer’s figure, this could be a varanid supraorbital indeed, but a precise description is hindered pending the recovery of the specimen.

In the same collection, a group of six undescribed caudal vertebrae from Pikermi were found. Although incomplete, these specimens, IPUW 5187, clearly belong to a monitor lizard. Given that they come from the type locality, these vertebrae are here referred to the hypodigm of Varanus marathonensis as topotypes. The three better-preserved vertebrae (Fig 2), still in connection, are described collectively below. The anterior edge of the neural arch is slightly notched and does not host any zygosphene. In dorsal view, the anterior surface of the neural arch is characterized by a triangular, deeply recessed area delimited by the ridges connecting each prezygapophysis to the neural spine. A weak but evident sagittal keel is present in the posterior sector of such area. The neural spine is developed in the posterior half of the neural arch; its dorsal development cannot be evaluated due to its incompleteness. The prezygapophyses have roundish facets that are dorsally tilted. The shape of the postzygapophyseal facets most probably matches that of the prezygapophyseal ones. A weak ridge links the pre- and postzygapophysis on the lateral side of the neural arch. The transverse processes are broken off but their remnants clearly indicate a subhorizontal orientation of their base. The ventral rim of the cotyle and condyle is placed posteriorly to the dorsal rim. The cotyle and condyle were probably dorsoventrally flattened. The ventral surface of the centrum has a median constriction (not exactly a precondylar constriction) and hosts two nearly parallel ridges delimiting between them a flat, rectangular region. The ridges originate from the cotyle and terminate into the pedestal for the chevron bone (the only preserved pedestal is the right one of the anterior vertebra). The centrum length of the best-preserved vertebra (the one in the middle) can be estimated to be about 14 mm.

The three other fragmentary vertebrae are isolated, poorly preserved and much smaller in size. The centrum length of the only sufficiently preserved vertebra nearly reaches 9 mm. Their morphology does not differ from that described for the other vertebrae, except for the fact that they are distinctly more elongate.

Description of the material from Abocador de Can Mata.

IPS50119 is the best preserved and largest (43 mm long) of the maxillae analyzed in this study (Fig 3A–3D). The element is highly fractured but most of the fragments are still placed in their original position or have been only slightly displaced. The dorsal area of the facial process, located in the posterior half of the maxilla and preceded by a wide concavity corresponding to the naris, is the only structure that is broken off. All the external and internal surfaces of the maxilla are unsculptured. All along the lateral surface of the maxilla, close to its ventral edge, there is a row of at least ten irregularly aligned alveolar foramina extending from the first to the tenth tooth position; the last foramen is by far the largest, followed by the first one. There is no clear trend in the size of the foramina. The ventral edge of the maxilla is slightly eroded anteriorly (mostly at the level of the third tooth position). Nevertheless, in lateral view, it has no trace of supradental thickening but has a shallow concavity corresponding to the tooth positions from five to nine; in ventral view, it is nearly straight. The anterior part of the maxilla is medially expanded and forms a large lateral premaxillary process and a much smaller medial premaxillary process. The lateral premaxillary process flares in a mediolateral direction, it is apically rounded and, assuming negligible deformation, slightly curved dorsally. The medial process has an irregular medial edge, but it seems to be fairly complete; it is about five times smaller than the lateral process and pointed. The dorsal margin of the medial process is raised into a well-developed, tall and laminar crista transversalis, whereas the crista lateralis of the lateral process is not developed apically (it is present only at the base of the lateral process). The narial margin is therefore nearly smooth in the area of the lateral premaxillary process. A very shallow sulcus is developed along the narial margin in correspondence to the first two tooth positions, then its rims become progressively more elevated in posterior direction (thereby making the sulcus deeper): the lateral rim disappears on the lateral surface of the facial process at the level of the fifth alveolus; the medial rim gives origin to a distinct ridge along the posterior narial margin (on the anterior sloping edge of the facial process), which is clearly visible from the third to the seventh tooth position. The crista transversalis seems to converge with the latter ridge at the level of the fourth alveolus, where an approximately transversal breakage, with margins not perfectly fitting, splits the maxilla. The anterior edge of the lamina intercristalis corresponds to a distinct concavity developed between the lateral and the medial premaxillary processes. Posteriorly, the lamina is clearly recessed between the crista transversalis and the ridge at the posterior narial margin (crista lateralis). The anterior portion of the maxilla gradually slopes in posterodorsal direction toward the facial process, whose dorsal tip is broken off between the seventh and the ninth alveolus. The anterior, sloping surface of the facial process is mediolaterally wide and concave because it develops a medially directed, broad and slightly concave lamina (somehow the continuation of the crista transversalis), whose medial edge is ventrally thickened by a sort of ridge. This medially-expanded lamina is laterally delimited by a blunt ridge. In medial view (Fig 3B), it is clear that the lamina is not confluent with the palatal shelf. In dorsal view (Fig 3C), a deep medial concavity separates this lamina and the crista transversalis. The external surface of the facial process is weakly concave dorsally to the irregular line of the alveolar foramina. The posterior maxillary process, well preserved in the area for the contact with lacrimal and jugal, is short and stout. Its tip is posterolaterally directed. The palatal shelf, medially to the crista transversalis, is slightly broken but clearly characterized, in medial view, by a distinct ventral concavity corresponding to the third, fourth, and part of the fifth tooth positions. The palatal shelf is nearly straight from the sixth to the ninth positions, and bends downward posteriorly to the half of the ninth position. On the medial surface of the maxilla, dorsal to the palatal shelf, there are three main excavations (Fig 3B). The anterior one is delimited dorsally by the crista transversalis and ventrally by the concave sector of the palatal shelf (corresponding to the tooth positions three to five). In correspondence of the anterior margin of the fifth tooth position, such excavation hosts a large foramen (foramen at base of facial process sensu [51]). Posteriorly to the mid of the fifth tooth position, a very wide, deep second excavation, the lacrimal recess, is delimited dorsally by the above-described medial lamina of the facial process, laterally by the facial process and ventrally by the palatal shelf. The posterior excavation, for the contact with jugal, develops posteriorly to the mid of the ninth tooth position (where the palatal shelf forms a distinct step posterior to which it bents posteroventrally); it is anteriorly marked by a weak ridge, and delimited laterally by the medial surface of the posterior maxillary process and ventrally by the palatal shelf itself. The forked shape of the posterior end of the palatal shelf is probably due to breakage (Fig 3C and 3D). The palatal surface of the palatal shelf does not host any dental gutter because the shelf forms a very obtuse ventral angle with the lateral wall (with the exception of the above-mentioned area corresponding to the concavity between dental positions three to five). The tooth row is represented by 10 tooth positions, of which the first, fifth, seventh, and ninth host at least a remnant of a subpleurodont tooth (sensu [52]). The tooth in the first position is truncated close to its base; the one in the fifth position lacks only the tip; the two others are complete, but fractured. The size of the tooth positions increases up to the central ones (from five to seven) and then decreases. The first and ninth teeth are substantially smaller than the other preserved teeth. All preserved teeth are mediolaterally flattened, pointed, and posteriorly curved. They have unserrated keels. The distal keels are more evident than the mesial ones, which are apparently rather worn (the best visible proximal keel is that of the tooth in the seventh position). The orientation of the keels is not parallel to that of the lower edge of the maxilla, but slightly transversal, the tips of the teeth pointing in posteromedial direction. All the preserved teeth are characterized by basoapical grooves (developed for about half of the length of the tooth), thus betraying the presence of plicidentine. This presence is also indicated by the lamellae [53] visible on the section of the first tooth, which is truncated close to its base. Among the tooth positions not hosting teeth, the second and third are clean of matrix and the palatal shelf shows a rough surface with irregular furrows.

The second maxilla IPS50292 (Fig 3E–3H) is smaller (length of the preserved portion: 32.20 mm) than IPS50119 but shares with it all the basic features that are visible in the preserved areas not covered by matrix. It is remarkable the presence in the anterior sector of the narial opening of the lateral sulcus, which is visible in both lateral and dorsal views (Fig 3E and 3G). The lateral rim of this sulcus is more defined than in IPS50119 and, as in the latter, the lateral ridge delimiting the groove terminates on the lateral surface of the facial process, where a foramen filled with matrix is located. Even if the crista transversalis is not preserved, the remnants of the lamina intercristalis indicate the presence of a concavity shallower than that visible in IPS50119. The medially directed, broad and slightly concave lamina on the anterior, sloping edge of the facial process is comparatively more developed in IPS50292 than in IPS50119. The preserved portion of the palatal shelf clearly confirms the presence in IPS50292 of a ventral flexure terminating dorsal to the (presumed) fifth tooth position. The anterior extent of the flexure is unknown because the palatal shelf is broken off. At least eight tooth positions are preserved. Three teeth are present in the anterior sector of the maxilla. Their size is obviously different, but their shape and orientation is congruent with that described above for IPS50119.

IPS57544 is represented by two tooth-bearing bone fragments. The largest corresponds to two tooth positions, the smallest just to one. None of them preserves a complete tooth, but both show the remnants of labiolingually-compressed teeth with longitudinal basal striations. Due to erosion, such striations are well visible, and one of the two teeth of the largest fragment, broken nearly transversally, clearly shows the internal lamellae typical of the plicidentine.

None of the available four trunk and four caudal vertebrae (Fig 4A–4J) is complete nor, if nearly so, completely free of matrix. Trunk vertebrae are characterized by a proportionally massive, long centrum (the length of the posterior fragment of IPS42353 is 15.42 mm, Fig 4A and 4B; IPS43719 is 18.36 mm long, Fig 4E and 4F) with a flat ventral surface. Both the cotyle and the condyle are noticeably dorsoventrally depressed. The cotyle is 3.52 mm high and 8.90 mm wide in IPS42362; the condyle is 5.20 mm high and 10.08 mm wide in IPS42353, and approximately 3.92 mm high and 9.41 mm wide in IPS43719. Due to a different development of their dorsal and ventral rims and edges, the cotyle faces in anteroventral direction, whereas the condyle does in posterodorsal direction. The ventral margin of the condyle is located nearly at the posterior edge of the vertebra. The condyle is separated from the centrum by a marked precondylar constriction (see arrows in Fig 4B and 4F). The ratio between the width at constriction and the width of the condyle is 0.74 in both IPS42353 (7.43 mm/10.08 mm) and IPS57546 (7.58 mm/10.24 mm). As shown by IPS42362 (Fig 4C), on the neural arch there are no distinct depressions between the prezygapophyses and the basis of the neural spine, and there is no hint of zygosphene. The diameter of the neural canal is very small if compared to the vertebra (Fig 4D). The prezygapophyses are dorsally tilted, forming in IPS42362 an angle of about 110° with the anterodorsal edge of the neural arch. The prezygapophyseal facets are oval and markedly elongated in anterolateral direction. The postzygapophyseal facets are similarly oval but are posterolaterally directed. In IPS57546, the lateral development of the prezygapophyses significantly exceeds that of the postzygapophyses. The shape and orientation of the synapophyses varies according to the position of the vertebra within the vertebral column. They can be nearly dorsoventrally oriented, with a ventral edge developed in anterior direction and nearly reaching the cotyle, as in IPS43719, or relatively large, clearly visible in dorsal view, dorsoventrally flattened and anteroposteriorly developed in a nearly horizontal plane, as in IPS42362. The posteroventral surface of the neural arch does not host any zygantrum. The surface of the neural arch, lateral to the neural spine, can be finely striated. None of the dorsal vertebrae preserves a complete neural spine.

Caudal vertebrae (Fig 4G–4J) are characterized by a centrum generally provided with two weak hemal keels connecting the cotyle to the pedestals for the chevron bones placed close to the condyle. The hemal keels are not present in the fragmentary caudal vertebra IPS49408. The pedestals have an oval surface (with a main axis longitudinally developed) facing in posteroventral direction. The cotyle and condyle have a ventral edge well posterior to the dorsal edge; their shape varies according to the position of the vertebra in the tail. The cotyle is markedly flattened dorsoventrally in IPS42400. The ventral surface of the centrum is slightly convex in IPS57547 (the centrum length corresponds to approximately 12.50 mm). The elongated centrum of IPS42400, 10.30 mm long, has sides nearly parallel in ventral view, with a weak interzygapophyseal constriction placed at mid length between the synapophysis and the cotyle; there is no clear precondylar constriction (but the exposed side of the centrum preceding the condyle is slightly damaged). Similarly, IPS42368 has no precondylar constriction. It is present but only moderately developed in IPS57547, because the ratio between the width at constriction (7.18 mm) and the width of the condyle (8.43 mm) is 0.85. A depression between the prezygapophyses and the basis of the neural spine is clearly absent (as in IPS42368), but a ridge links each prezygapophysis to the base of the neural spine, therefore delimiting a concave dorsal surface at the anterior edge of the neural arch. In IPS57547, the prezygapophyses are anterolaterally directed and dorsally tilted; the shape of their facets is oval and noticeably elongated. The postzygapophyses are small, tilted and with oval facets. The postzygapophyseal facets are tilted about 45° in IPS42368. The transverse processes are laminar. Their base is nearly horizontal in lateral view, but they are apically pointing in posteroventral direction (as in IPS42400). The posterior tip of their base can be connected by a ridge to the condyle. The basis of the neural spine develops in the posterior area of the neural arch. IPS42368 shows a depression on the basal anterior surface of the neural spine. The only well-preserved neural spine is that of IPS42400. It is very tall (15.52 mm), moderately inclined posteriorly, slightly expanded distally, and nearly truncated apically.

Description of the isolated material from Batallones-3.

The two fragmentary maxillae from BAT-3 apparently belong to a single individual. The right maxilla BAT-3 1088a (Fig 5A–5D) is better preserved than the left one, BAT-3 1088b (Fig 5E and 5F). BAT-3 1088a is represented by four fragments glued together. The total length of the maxilla is of 32.40 mm. The medial premaxillary process and part of the facial process are broken off but the palatal shelf preserves the entire series of nine tooth positions: teeth of the second, fourth, sixth, seventh, and eight positions are still in place. The morphology of this maxilla, including tooth morphology, is congruent with that of IPS50119 and IPS50292. It is remarkable the presence of the same sulcus delimited by ridges at the lateral edge of the narial aperture (Fig 5A and 5C), and the morphology of the anterior surface of the facial process (Fig 5C). The sulcus reaches posteriorly the level of the fifth interdental position. Despite its incompleteness, the anterior surface of the facial process is dorsally concave and significantly developed in medial direction all along the anterior, sloping surface of the process itself. Particularly wide is the foramen of the jugal trough which opens dorsal to the palatal shelf at the level of the last interdentary space. The posterior end of the palatal shelf is complete and not forked as in IPS50119. Probably due to breakage, the step on the palatal shelf marking the contact area with the jugal (see IPS50119) is not present.

BAT-3 1088b is represented just by a portion of palatal shelf corresponding to eight tooth positions and a little part of the facial process. Just the third preserved position hosts a tooth. None of the characters described above can be discerned on this element.

Two unnumbered isolated teeth and about a dozen bone fragments likely belong to these two maxillae.

The right prefrontal BAT-3 1088c is a rather well preserved triradiate element (Fig 6). The main body and the sublacrimal process are complete, whereas the frontal process and the maxillary flange are apically broken off. Dermal sculpturing and canthal crest on the external surface of the main body are absent, but this surface is slightly rough. The main body is dorsally expanded in medial direction and it significantly overhangs the paranasal recess. The internal surface is characterized by a deeply-excavated paranasal recess. The recess is very well delimited posteriorly (where the frontal process originates). Its smoothness is just altered by a little ridge along the maxillary flange. A little foramen opens on the posterior wall of the recess. The triangular base of the frontal process is stout and thick. The fact that it tapers abruptly could indicate that it was not particularly long. The dorsal surface of the frontal process has an evident knob. There is a little notch at the boundary between the base of the frontal process (the anterior limit of the orbital surface of the frontal process) and the antorbital flange. The latter is markedly convex. The medial surface of the tip of the sublacrimal process has a small but distinct notch, which contacted the palatine. The rim of the lacrimal foramen, located between the maxillary flange and the sublacrimal process, is wide and quite concave. The maxillary flange bears the mark left by the overlapping facial process of the maxilla. Such mark is well defined posteriorly, but rather faint dorsally. With the exception of a tiny foramen located dorsal to the rim of the lacrimal foramen, no evident foramina open on the external surface of the prefrontal. The subpalpebral fossa is also absent.

Description of the nearly complete skeleton from Batallones-3.

The nearly complete skeleton from Batallones-3 is represented by at least 119 skeletal elements, originally found close to each other, corresponding to the following collection numbers MNCN BAT-3 2011–200, –252, –148, –2626, –2627, –2628, and –2629.

Premaxilla–The premaxillae (Fig 7A and 7B) are fused in a single element (MNCN BAT-3 2011–200a). They only partially preserve the long nasal process, but the overall preservation is relatively good, despite the presence of concretion partially hiding the morphological characters. The anterior edge of the premaxillae is roundish and there is no rostrum anterior to the teeth. The right ethmoidal foramen, despite being filled with concretion, is clearly visible on the external surface (more so than the left one). The internal aperture of these foramina is not visible. Three teeth are preserved to the right of the central tooth, whereas only two are visible to the left (plus a small replacement tooth); therefore at least six tooth positions are partially preserved, but their original number could have been slightly higher. Teeth are pleurodont, approximately conical, with a blunt tip and without any sharp keel. They are equal in size. A smooth edge on the right posterolateral sector of the basal plate indicates the presence of a premaxilla-maxilla aperture (due to preservational reasons, neither maxillae show the corresponding notch). The incisive process is present, but because of preservation it is not clear if it was bipartite or not. The general morphology of the basal plate and of the preserved base of the incisive process clearly indicates that the anterior tips of the missing septomaxillae were far from the anterior tip of the premaxilla. The nasal process is much more developed dorsoventrally (3.60 mm) than mediolaterally (1.40 mm). This narrow morphology is an apomorphic feature of Varanus according to our phylogenetic analysis. The total length of the preserved portion is 19.20 mm.

Maxilla–Both maxillae are available, but none of them is complete (Fig 7C–7E). Both their anterior and posterior tips are preserved. Their total length is 43.10 mm (right maxilla) and 42.80 mm (left maxilla). The presence of a concretion hinders the perception of some of the finer morphological details. The concretion adhering to the medial side of the right maxilla embeds two as yet unidentified skeletal fragments that partially cover the maxilla. The tooth positions can be counted with confidence only on the left maxilla, where they are nine, but the same number is likely valid also for the right maxilla. The latter still hosts some teeth or their remnants in the positions one, three, five seven and (just a very basal portion) nine. The left maxilla hosts teeth in the positions one to five and then seven. In both maxillae, the concretion keeps approximately in place some small replacement partial teeth: two teeth are visible in the space of the second tooth position, whereas on the left element two teeth precede and follow the second tooth.

Both maxillae are characterized by the medially expanded ascending surface of the facial process and by the lateral sulcus developed along the narial margin. The medial expansion of the facial process is testified by its remnants that are preserved nearly at the dorsal tip of the facial process of the left maxilla (which is not laminar but has a medial, yet broken, expansion; Fig 7C and 7E). The expanded lamina has two main depressions located dorsal to the third and sixth tooth positions. The narial edge of the maxilla is nearly horizontal dorsal to the first four positions, then steep dorsal to the fifth and sixth positions, and is markedly steeper dorsal to the seventh and eight positions (that is to say, up to the dorsal tip of the facial process). The lateral sulcus developed along the narial margin extends on both maxillae from the second to the fourth tooth position (Fig 7D).

The left maxilla preserves the tip of the facial process, which corresponds to the eight tooth position. In lateral view, it is apically rounded and it overhangs the deeply concave lacrimal recess.

Palatine–A nearly complete left palatine (Fig 7F and 7G) is preserved adhered by matrix to the ventrally overlapping palatine process of the pterygoid (BAT-3 2011–200s). It is a triradiate element only slightly longer than wide. The complete vomerine process is an elongate laminar structure directed anteromedially but also slightly ventrally. The robust maxillary process is only partly preserved; it is anterolaterally directed but morphological details are not visible for preservational reasons. The pterygoid process is directed posteriorly, comparatively wide, laminar and it bifurcates apically. The medial edge of the palatine, linking the vomerine and the pterygoid process, is markedly concave, without any medial expansion. The palatine groove is short without any secondary palate. The presence of concretion at the level of the anterior infraorbital continuation of the maxillary process betrays the probable location of the palatine foramen. Palatine teeth are absent. This absence is apomorphic for Varanus in our phylogeny.

Pterygoid–A left pterygoid is nearly completely preserved (Fig 7H and 7I), being represented by the main body, the palatine and tranverse processes and most of the quadrate process, which misses its basal portion. The basypterygoid buttress and the columellar fossa are not preserved. The tips of both the palatine and tranverse processes are incomplete (the one of the palatine process is preserved along with the palatine BAT-3 2011–200s). There are no pterygoid teeth. As for the missing palatine teeth, the absence of pterygoid teeth is an apomorphy of Varanus (characters 394 and 395 in the phylogenetic analysis have been scored as “?” in the corresponding coding in agreement with the scores for the other Varanus species in the matrix, but these characters are actually non-applicable because none of the Varanus species have pterygoid teeth). The transverse process is rather thick and tall laterally. Its lateral edge is flattened and develops dorsally in a sort of lamina and ventrally in a rounded expansion. The lateral margin of the transverse process is convex, whereas the medial one, hosting the contact facet with the ectopterygoid, is concave. Both the dorsal and ventral surfaces of the main body of the pterygoid are somewhat concave. The edge of the pterygoid between the transverse and the palatine processes is laminar and concave. The posteromedial edge of the transverse process is thicker than the anterolateral one. A distinct ridge runs along the quadrate process, presumably at the ventromedial edge, and the medial surface is weakly concave dorsal to it.

Ectopterygoid–BAT-3 2011–200r is a right, partially preserved ectopterygoid (Fig 7J and 7K). Even though it is incomplete, this element is clearly slender and elongate. The anteriorly placed dorsal pterygoid process is more complete than the posterior region, which preserves only the cavity that hosted the transverse process of the pterygoid. By the general architecture of the palate, it is clear that the ectopterygoid contacted the palatine anterior to the suborbital fenestra.

Lacrimal–A left lacrimal, rather well preserved (Fig 7L and 7M), was found in the lacrimal recess of the maxilla. It is 10.30 mm long. The posterolateral flange, constituting the anterior margin of the orbit, is distinctly developed in a distinct, rounded process whose lateral surface is slightly rugose. The anterior edge hosts laterally the contact surface with the maxilla, and medially that of the prefrontal, whereas the posteroventral tip hosts that of the jugal. At the edge of the ventromedial surface, there is a distinct notch for the contact with the palatine. The ventral opening of the lacrimal foramen [54], filled with sediment, seems to be rather large and opens close to the posteroventral border of the element, by the contact facet with the palatine.

Quadrate–The two quadrates are well preserved. The left element (Fig 7N–7P) is more complete than the right one, lacking only a small ventral portion of the medial crest. These two elements are taller than broad, 19.30 mm and 10.60 mm, respectively. The posterior crest originates ventral to the wide surface for the articulation with the squamosal. It is robust and deeply concave in its dorsal sector. The lateral, or tympanic crest, straight both in lateral and posterior views, is well developed, being only slightly shorter than the maximum width of the posterior crest. The medial crest, slightly curved in medial view, develops in anteromedial direction giving origin to a deep fossa on the anterodorsal surface of the bone. The lateral rim of the fossa is marked by an evident ridge. The saddle-shaped articular condyle shows a lateral hemicondyle much smaller than the medial. The latter develops a process in anteromedial direction, at the base of the medial crest.

Prefrontal–Both prefrontals are preserved (Fig 8A and 8B). The right element (21.20 mm long, 18.30 mm high) is more complete, but also more fractured, than the left one. Their morphology is congruent with that already described for BAT-3 1088c, with some minor differences related to the absence of a knob on the dorsal edge of the bone and the absence of foramina on both the external and internal surfaces. As in BAT-3 1088c, there is no evident sculpturing of the external surface, but a V-shaped scar corresponding to the contact with the supraorbital is present at the dorsolateral edge of the left element (the right one is not well preserved in that area). As in BAT-3 1088c, there is no evidence for the subpalpebral fossa.

Supraorbital–The right supraorbital is nearly complete (Fig 8C and 8D). Its mediolateral length is 13.30 mm. It has the shape of an elongated, posterolaterally directed spine. The proximal end, deeper posteriorly than anteriorly, is much thicker than the pointed tip. The dorsal surface is slightly irregular close to the proximal end, where both the anterior and medial edges are distinctly crenulate. The vaguely triangular medial surface is centrally smooth but crenulate at the edge (it is eroded in the posteroventral sector).

Frontal–The two paired frontals (Fig 8E–8I) are well preserved, and the left one (32 mm long, 12.10 mm wide) is nearly complete. Their dorsal surface is vaguely sculptured. The lateral edge of the dorsal surface is nearly straight, but at mid length it shows a small lateral expansion corresponding to the dorsal notch in the neighboring prefontal. The anteriorly tapering tip of the left element preserves a medial, partly broken, lamina that underlay the nasal, and also the lateral surface, laterally bordering the nasal, that represents the posteromedial edge of the osseous external naris. The contact between the (probably paired) nasals and the frontal is W-shaped. The posterior tips of the nasals were therefore separated from each other and tapering posteriorly in an apically rounded point. There are no nasofrontal fontanellae. The lateral surface hosts anteriorly a marked, wide, V-shaped contact surface for the prefrontal, whereas close to the posterior edge there is the contact surface with the frontal process of the postorbitofrontal. The medial surface is proportionally very thick (4 mm) and characterized by fine striations interlocking in the two opposed frontals when articulated. The posterior surface hosts a markedly interdigitated suture for the parietal. At least the median region of this sutural contact is convex (both the frontals have broken posterolateral edges). Even though they are incomplete in both frontals, the cristae cranii are represented by well-developed, ventromedially directed laminae well delimiting the olfactory tract. The crista of the right frontal, better preserved than that of the left counterpart, is well developed in medial direction, reaching the level of the medial margin of the dorsal surface of the bone (Fig 8I). This indicates that the cristae were ventromedially in contact in the posterior region of the frontal. The intertemporal width is of about 11.60 mm. The parietal tabs are present (an apomorphy of Varanus in our phylogenetic analysis).

Postorbitofrontal–Both the right and left elements preserve their anterior portion, which is characterized by the three evident processes: the anterolateral process, the frontal process and the parietal process (Fig 8J and 8K). The anterolateral processes are robust and pointed with a dorsal surface distinctly irregular. The posterior surface of the frontal process and the medial surface of the parietal process are complementary to that of the bones they contact: the first one is approximately concave, whereas the latter is sloping in ventromedial direction. The left postorbitofrontal also preserves part of the posterior ramus (the squamosal process), the relative robustness of which indicates that it was very long originally (Fig 8J and 8K). The lateral surface of this process hosts the elongated contact facet with the squamosal. Anteriorly, an obtuse angle is formed by the anterolateral and frontal processes, as in V. mokrensis [5]. In contrast with the latter species, however, the squamosal and parietal processes form a very wide angle in the Iberian specimen and the margin between them is distinctly concave (the angle is acute and the margin is V-shaped in V. mokrensis [5]). Moreover, the angle made by the frontal and parietal processes is strongly wider in V. mokrensis compared to the specimen from Batallones. The postorbitofrontal does not contact the jugal nor the prefrontal.

Parietal–This unpaired bone is nearly perfectly preserved (Fig 8L and 8M). Only the tips of the supratemporal processes, the right one more extensively than the left one, are broken off. It is a nearly X-shaped element, with a nearly straight anterior edge and deeply concave lateral and posterior margins. It is 30.70 mm wide at the anterior edge and 33.30 mm long and it is characterized by a marked thickness (about 7.30 mm at the level of the pineal fossa). The intertemporal width corresponds to 12.40 mm. The dorsal surface is flat and its anterior half is slightly vermiculate. The anterior edge has a medial, small anterior projection that slightly separates the frontals from each other. The pineal foramen pierces the parietal just a few millimeters from its anterior edge, well anteriorly to the posterior edge of the facets for the contact with the postorbitofrontal. The lateral edges of the parietal anteriorly host the facets for the contact with the postorbitofrontal and posteriorly form the deeply concave rim of the supratemporal fossae. The surface delimiting the fossae is concave anteriorly but only lateroventrally sloping posteriorly. In the latter area, a thin, approximately longitudinal ridge develops close to the dorsal edge of the parietal.

The supratemporal processes are very long (they are only slightly shorter than half the total length of the parietal) and their preserved tips are 33.80 mm from each other, so that the anterior width of the bone is smaller than the posterior one. The processes are directed posterolaterally in dorsal view and slightly ventrally in lateral view. The posterior angle between the processes is about 90°. Their short axis is ventrolaterally directed. They are somewhat rounded dorsally (but not broad or flat) and rather sharp ventrally. The facets for the contact with the supratemporal extend anteriorly at the level of (on the left) or well beyond (on the right) the anterior limit of the processes, and occupy most of their lateral surface. The contact facets at the distal tip of the supratemporal processes are not preserved or visible with confidence, except for the supratemporal facet that could be present on the left process. The ventral surface of the parietal hosts at its lateral edges, anteriorly to the supratemporal processes, the descensus parietalis (or crista cranii parietalis), a moderately deleveloped crest nearly anteroposteriorly oriented. The fossa parietalis opens posteriorly and is delimited ventrally by a well-developed ridge, the crista juxtafovealis that gives origin to the crista postfovealis, running along the medial surface of the supratemporal processes.

Braincase–The braincase is represented by the isolated parabasisphenoid (Fig 9A–9D) and by a complex including the supraoccipital, the prootics, the otooccipitals and the basioccipital (Fig 9E–9I). The complex is not well preserved, being highly fractured (in some cases with little dislocation) and partly covered by concretion. The left paroccipital process is separated from the rest of the braincase (Fig 9J and 9K) and the presence of a crystalline concretion on the contact surface prevents its reconnection. For preservational reasons, the right side of the complex is more informative than the left one.

The parabasisphenoid is much wider than long. Its ventral surface (as well as that of the basioccipital) is smooth and devoid of any sagittal ridge or recess (Fig 9B). The basipterygoid processes are long, anteroventrally directed, apically expanded and rounded. Their medial surface is convex, whereas the lateral one is flattened. Part of the base of the parasphenoid process and of the trabeculae cranii is preserved. This portion of the bone hosts dorsally two longitudinal ridges, the cristae trabeculares, separated by a sagittal groove. Another groove laterally borders each of the ridges. The ventral surface is smooth. The left trabecula cranii is nearly complete. Lateral to the base of the trabeculae cranii, the small anterior openings of the Vidian canal are located on both sides, being therefore significantly ventral to the dorsum sellae. The latter is rather shallow. The posterior opening of the Vidian canals is clearly visible on the left side: it is completely hosted by the parabasisphenoid. The abducens canals (cranial nerve VI) pierce the bone on the dorsum sellae, close to its anterolateral edge, and on the anterior surface, just medial to the alar processes. The alar processes are robust and anteroventrolaterally directed. The pituitary fossa is filled with concretion and therefore the openings of the carotid canals are not visible. The posterior articulation facets for the basioccipital are tall and robustly built. There is no clear entocarotid fossa within the recessus vena jugularis dorsal to the base of the of the basipterygoid processes of the basisphenoid. The posterolateral flanges of the parabasisphenoid are not developed.

The sutures between the supraoccipital and the surrounding elements are well visible (Fig 9H and 9I). This unpaired element is vaguely pentagonal and characterized by a dorsal surface raised in a broad sagittal ridge. The anterior tip of the supraoccipital, the processus ascendens, is anterodorsally oriented and apically truncated. Lateral to the anterior truncation, it hosts the two contact facets for the lateral rims of the fossa parietalis. The internal surface of the supraoccipital, close to the suture with the prootic, it shows a convexity corresponding to the anterior semicircular canal. Posteriorly, the supraoccipital forms the dorsal margin of the foramen magnum.

Both the prootics preserve the long, anterodorsally and relatively pointed alar process, each distinctly overhanging the relative inferior process (Fig 9E). The fenestra ovalis, as well as the foramen rotundum, cannot be seen directly because of the concretion covering it. However, its absence in the area anterior or dorsal to the sphenooccipital tubercle indicates that it is located posterior to it. For the same reason, it has not been possible to evaluate whether the facial foramen is single or double (but it is single in the remains from Samos attributed to V. amnhophilis; [11]). The prootic contribution to the paroccipital process extends posterolaterally over more than two-thirds of the process (Fig 9F and 9J). The well-developed right prootic crest clearly hosts a well-preserved accessory anterostapedial process, which is anteroposterioly elongate and ventrolaterally expanded. The internal surface of the prootics is markedly convex in correspondence to the semicircular canals.

The tip of the right paroccipital process is not complete but the isolated portion of the left one is perfectly preserved and shows that its dorsal and ventral tips extend equally posterolaterally (Fig 9J and 9K). The ventrolateral margin of the exoccipital part of the left paroccipital process has an accessory lip, which is distinctly offset with a dorsolateral step. On the external surface of the otooccipital, lateral to the dorsal edge of the occipital condyle, as well on the inner surface, between the rim of the occipital canal and the auditory bulla, the openings of the X and XII cranial nerves are present but obstructed by concretion. On the posterior surface, they are apparently hosted in the same depression, whereas on the internal surface they are clearly separated by a well-defined ridge.

Both sphenooccipital tubercles are preserved. They are evident but comparatively small and clearly directed ventrally. They are placed at the anteroventral tip of the tuberal crest. The occipital condyle is proportionally strong and very well defined. It is made ventrally by the basioccipital and laterally by the otooccipitals. The general shape is that of a broad U (Fig 9H).

The tuberal crests (Fig 9E) are laterally eroded (the left one much more that the right one), but it is clear that they inserted on the paroccipital process much more laterally than on the sphenooccipital tubercle. The crests are anteroventrally inclined and, in ventral view, they cover completely the laterally open recessus scalae tympani. The latter is better preserved on the right side of the braincase, but it is nearly completely filled with concretion and therefore most of the fine anatomical details cannot be seen.

Dentary–The two dentaries are isolated and rather well preserved (Fig 10A–10C). They are relatively robust, being proportionally tall and massive (i.e., not as slender and thin as in Varanus salvator). The right element (42.60 mm; Fig 10C) is more informative than the contralateral (38 mm; Fig 10A and 10B). It has ten tooth positions, seven of which still preserving teeth or their fragments (only the fifth, seventh and ninth positions do not host teeth). This number of tooth positions could be congruent with the arrangement shown by the left dentary, whose preservation hinders a precise count. The dorsal edge of the dentaries is clearly concave, whereas the ventral edge is convex. In dorsal view, they are rather straight, but the anterior tip is slightly curved medially. Their lateral, convex surface hosts some mental foramina. In the right dentary, there are six foramina. They are approximately aligned and the last one, corresponding to the posterior edge of the last tooth position, is by far the largest. Due to preservational reasons, only three foramina can be counted on the left element. In both dentaries, a small longitudinal sulcus is developed on the anterolateral surface, ventral to the first three positions and dorsal to the first foramen. The medial surface is characterized by the absence of a subdental ridge (the subdental table, sensu [55], is clearly sloping in medioventral direction with a smooth surface) and by a Meckel’s canal completely open along the entire length of the dentary. The canal is rather narrow in the anterior half of the dentary, where it is restricted to the ventral edge. It reaches the symphysial area, giving to the latter a kidney shape/reniform outline in medial view. The intramandibular septum terminates posteriorly to the last tooth position. Its posteroventral margin is sutured along the dentary wall. It is not clear if and how the dentaries contributed to the anterior inferior alveolar foramen. The morphology of the teeth fits with that described above for those of the maxillae from both the Vallès-Penedès Basin and Batallones. The posterior end is poorly preserved in both dentaries and the posterior processes are broken away.

Surangular, prearticular and articular–Due to fossilization, the right surangular, prearticular and articular are preserved together in a single unit 58.30 mm long (Fig 10D–10G), but they are not all fused together, being most of the sutures among the bones well visible. Their general preservation is relatively good and they provide significant morphological information.

The surangular, which is nearly complete, missing only part of the anterior tip and the area dorsally expanded below the coronoid, is robust. In dorsal view, it is distinctly convex laterally and concave medially. On the anteroventral surface, the surangular has an elongated facet that was overlapped by the missing angular. The ventral portion of this facet is developed on the prearticular. The anterior surangular foramen is visible just ventral to the area that contacted the coronoid. Despite being anteriorly preceded by a shallow concavity that was overlaid by the lingual flange of the coronoid’s anterior process, it is not associated to a groove. It seems likely that this foramen was dorsally bordered by the latter element. The posterior surangular foramen, which clearly opens entirely on the surangular, is close to the surangular-articular suture. The adductor fossa is comparatively small, not expanded, and has a low medial margin not producing a vertical flange. The posterior canal (sensu [56]) opens on the medial surface of the surangular, close to the articular. Anterior to the adductor fossa, the surangular has a drop-shaped facet that was overlapped by the posteriorly directed medial process of the coronoid. The prearticular does not show any crest. The articular forms the glenoid surface without any contribution from the surangular. This surface is characterized by a large, bulbous convexity mostly developed in anteromedial position, associated with a vaguely concave area that borders it posteromedially and posteriorly. The retroarticular process is rather long, massive, not posteriorly expanded, and slightly directed posteromedially.

Coronoid–Both coronoids are preserved (Fig 10H and 10I), but the right one is represented only by part of the dorsal eminence and part of the anterior processes. The latter process is rather long and relatively robust. The coronoid eminence, or coronoid process, is relatively tall and characterized by having a clearly crenulated posterodorsal edge. On the external surface, it has a well-marked ridge, oriented posterodorsally-anteroventrally, that reaches the mid of the preserved portion of the labial flange of the anterior process. The labial flange seems to be rather complete in both coronoids (in the left one the dorsal notch between the labial and lingual flange is preserved), and by superimposing it on the surangular it is clear that in labial view it did not overlap the posterior margin of the coronoid process of the dentary. The labial flange is more developed in ventral direction than the lingual flange. The posterior process of the left coronoid is represented only by a small portion, triangular in cross section, of the original process. The preserved portion of the left coronoid is 25.10 mm long.

Vertebrae–The atlas of the almost complete skeleton is missing, but the axis and the following six cervical vertebrae are preserved (BAT-3 2011–2626; Fig 11A–11E). They are all characterized by having a posteroventrally directed hypapophysis or at least a vestige of it. The hypapophyses of the axis and the cervical vertebrae from four to six are apically notched. The one of cervical vertebra three is rounded (Fig 11B and 11D). The cervical vertebrae are longer than the dorsal vertebrae. Twenty dorsal vertebrae are available (BAT-3 2011–2627; Fig 11F–11J). They are characterized by the absence of zygosphene-zygantra articulations (an apomorphic feature of Varanus in our phylogeny) and by a strong precondylar constriction. The ratio bewteen the minimum precondylar width of the centrum and the maximum condyle width varies, in the four vertebrae that can be measured, from 70.8% to 75.6% (8.5–12.0 = 70.8%, 8.8–11.9 = 73.9%, 9.0–11.9 = 75.6%, 8.3–11.6 = 71.6%). The centrum length is difficult to measure because most of the vertebrae are preserved in connection. Nevertheless, the length of the longest centrum may reach 15.30 mm.

A block of vertebrae cemented by matrix (BAT-3 2011–2628; Fig 12) contains the last trunk vertebra (with rather pointed synapophyses), the two sacral vertebrae, one cloacal vertebra (plus a fragment of a possible second one), and the first caudal vertebra. A further element could represent the proximal portion of the right ischium. There are also a metatarsal and a partial phalanx.

The first sacral vertebra has massive, laterally broad diapophyses (maximum width at the level of the diapophyses is approximately 39 mm, but the left one is not complete). The distal end of the right diapophysis has the shape of a V laying on one side, with the concavity oriented in posterior direction. The dorsal branch of the V is more robust and longer than the ventral one. The second sacral vertebra is better preserved and exposed than the first one. The estimated length of the centrum could reach approximately 15 mm. The diapophyses are slightly bent downward and their distal tip is simply anteroposteriorly elongated. The maximum width at the level of the diapophyses in the second sacral vertebra is of 37.50 mm. Two short longitudinal (following the main axis of the structure) ridges are located at mid length of each diapophyses, close to its posterodorsal and posteroventral edges. At least one vertebra associated to the sacral ones is interpreted as a cloacal vertebra lacking pedestals for chevron bones and synapophyses, but bearing transverse processes. It also lacks lymphapophyses.

Nearly all the tail is preserved on a slab where 51 vertebrae can be counted (BAT-3 2011–2629; Fig 13), with a gap of one vertebra before the last ten preserved ones. Very few chevron bones are associated to the vertebrae 21 to 26. No caudal vertebra shows any evidence of autotomic plane. All the caudal vertebrae are characterized by a single pair of long transverse processes, and by well-developed pedestals for the chevron bones. The pedestals are located slightly anterior to the posteroventral margin of the centrum.

Coracoid–A partial right coracoid is preserved (Fig 14A and 14B). The wide coracoid blade is fractured but nearly complete. It forms the posterior rim of a deep secondary coracoid fossa. Even though the anterior rim of the latter is not complete, it is possible to state that it was relatively small, about the size of the glenoid fossa. The coracoid foramen is located anteroventrally to the glenoid fossa. The thinning of the bone anterior to the coracoid foramen indicates the location of the primary coracoid fenestra. The shallow glenoid fossa is preserved, as is the surface contact with the scapula.

Humerus–Only the left humerus is available (Fig 14C–14F). Even if incomplete, it preserves both the proximal humeral head and the distal epiphysis, which are developed on nearly orthogonal planes. The total length of the humerus is 59.40 mm. An elongated unidentified bone is embedded in the concretion covering the humeral surface posterior to the deltopectoral crest. The head is significantly extended in posteroventral direction. The single deltopectoral crest is well developed in dorsal direction. The stout shaft is elliptical in cross section, with the main axis oriented anteroposteriorly (length of the axis = 7.80 mm), but widens considerably in distal direction (the width of the distal epiphysis is 19.80 mm). The entepicondilar fossa is rather deep and wide. The ectepicondyle is nearly completely broken off, but the hint of a groove can be seen on its ventral surface. The presence or absence of the entepicondilar and ectepicondylar foramina cannot be assessed because of preservational reasons. The radial condyle is thinner but much more developed than the ulnar condyle. The presence of distal articulations clearly indicates the presence of the non-preserved zeugopodial elements. As a whole, the humerus appears rather robust, similarly to the humerus of Varanus sp. reported by Georgalis et al. [57] from the late Miocene of Ravin de la Pluie. These authors suggested a short and stout-limbed morphology for Neogene varanids from Europe and the humerus of the Batallones specimen might support this conclusion, at least for V. marathonensis. Given that the very few fossil Varanus limb bones from the European continent cannot be clearly identified at species level based on our current knowledge, it is not possible to clearly state whether only V. marathonensis possessed this limb morphology or it was shared with other species.

Ilium–Both ilia are preserved (Fig 15A and 15B). The anteroposterior length of the right element is 42.40 mm. The anterior (preacetabular) process is stout, short and anterodorsally directed. The rod-like dorsal process is rather straight in lateral view, but moderately curved, with the tip pointing posterolaterally, in dorsal view. It bears a number of longitudinal striations. A main ridge is developed on the dorsal edge of this process, extending from the anterior process to about the mid of the dorsal process. Here, another ridge, located more medially than the former, originates and extends up to the posterior tip of the ilium. The iliac portion of the acetabulum cavity is wide and weakly delimited.

Femur–Both femora are preserved, but none is complete. The right element, BAT-3 2011–252f (Fig 15C–15F), is 65.30 mm long and lacks the femoral head. The left one, BAT-3 2011– 252e (Fig 15G and 15H), is 67 mm long and lacks most of the tibial condyles. The femoral head is expanded anteroposteriorly. The internal trochanter is well developed and stout. It is connected to the femoral head by a slightly concave surface. The diaphysis is proportionally robust (dorsoventral thickness of the left element: 8.20 mm), straight and nearly cylindrical, being only slightly flattened ventrally. The distal epiphysis is moderately expanded (20.40 mm), with two tibial condyles well separated by a distinct trochlea.

Tibia–The proximal end of a right tibia and a nearly complete left tibia are preserved. The complete element is 46.80 mm long (Fig 15I and 15J). The proximal epiphysis is dorsoventrally flattened and mediolaterally wide (18.90 × 11.20 mm). Both sides of the proximal epiphysis bear a robust ridge. The diaphysis is slightly dorsoventrally flattened. Its maximum diameter reaches 6.40 mm. It widens slightly towards the distal epiphysis, which is 11.10 mm wide.

Fibula—This robust element is represented by its proximal portion (Fig 15K), characterized by a vaguely drop-shaped articulation.