Maximum Parsimony analysis.

The data matrices and the lists of characters are presented as Supporting Information (S2 Text, S1 File, S4 Table). We perform a Maximum Parsimony analysis to check the position of the giraffid from BAT10 within the Giraffidae, exploring provisionally the phylogenetic structure of the group. We use a morphological dataset of 111 characters (cranial, dental and postcranial), with 31 taxa including those in the outgroup. We used TNT v1.5-beta software [75] to analyze the dataset. All characters are non-additive and un-weighted, and we analyzed the trees using a Traditional Search method (heuristic algorithm) with Tree Bisection Reconnection (TBR) and 1000 replicates (holding 10 most parsimonious trees for each replicate). We used Bremer (BREMER.RUN) to assess branch support.

Emended diagnosis.

Large giraffid with two pairs of ossicones. Smaller anterior pair located above the orbits and anteriorly oriented. Larger posterior pair located posterior to the orbits and posteriorly oriented. Posterior ossicones curved, showing a high number of ridges on their surface. Elongated dp3 and dp4. The dp3 has a posterolingual conid lingually attached to the posterior stylid, mesolingual conid absent, and anterior conid and anterior stylid separated. Elongated DP3 with the anterior lobe almost twice as long as the posterior one, presence of a strong and very wide anterior style, strong buccal cone, and unfolded lingual cone. p2 very simple, without mesolingual conid and with a coniform mesobuccal conid. p3 with posterobuccal conid always attached to the mesobuccal conid, and absence of a mesolingual conid. p4 of variable morphology, with continuous lingual wall, and posterobuccal conid always attached to the mesobuccal conid. Lower molars sporting weak metastylid that fades with wear, and no buccal or lingual cingulids. The m3 has a well-developed third lobe, a semicircular hypoconulid and a strong entoconulid. Upper molars are more longer than wide, with parallel and weak styles, poorly developed buccal cingulum, separated lingual cone and metaconule, occlusally exposed dentine area that fuses late with wear, and no basal pillars. Postcranial skeleton with limbs of medium length and robustness. Metacarpal III–IV with a shallow to medium posterior trough.

Etymology.

Rex, latin for king. Referring to the exceptional fossil remains of this species, that turn it into the king of the Miocene Iberian giraffids.

Diagnosis.

A large giraffid with two pairs of ossicones. Smaller anterior pair located above the orbits and anteriorly oriented. Larger posterior pair located posterior to the orbits and posteriorly oriented. Posterior ossicones curved, showing a high number of ridges on their surface. Middle indentation of the hard palate slightly posterior to the M3. Broad occipital. Long premaxillae. Elongated diastema. p3 lacking mesolingual conid. Slightly molarized p4. Cervical vertebrae of medium length. Scapula with acromion. Robust postcranial skeleton. Metacarpals of medium length showing a medium depth palmar trough. Differs from Decennatherium pachecoi in: p3 with an isolated wall-like mesolingual conid structure; anterior stylid and conid of the p3 always present; and more robust metapodials.

Holotype.

BAT10’13.E2-69, skull with ossicones and mandible (Fig 3).

Paratypes.

The remaining referred material from BAT10.

Locality, age and horizon.

BAT10, Cerro de los Batallones, late Vallesian, MN 10, local zone J, Madrid province, Spain. (ca 9 Ma) (Fig 1).

Material.

BAT10’13.E2-69 (skull), BAT10’08.G3-91(skull), BAT10'09 F3-102 (skull), BAT10’07.G4-127 (calvaria with ossicones), BAT10'08 F1-112 (calvaria with ossicones), BAT10’13.D5-16 (right posterior ossicone), BAT10’13.D5-16 (left posterior ossicone), BAT10’09.F2-97 (left posterior ossicone), BAT10’07.G3-9 (right posterior ossicone), BAT10’10.F3-22 (posterior ossicone fragment), BAT10'07.S1 (posterior ossicone fragment), BAT10'08.F4-49 (right maxillar with P2-M3), BAT10’10.F3-64(right maxillar with P2-M3), BAT10’08.G1-33 (right maxillar with P2-M3), BAT10’13.D5-81(right maxillar with P2-M3), BAT10’08.F3-30(left maxillar with P2-M3), BAT10'07.H4-39 (left maxillar with P2-M3), BAT10’08.G1-45 (left maxillar with P2-M3), BAT10’13.E4-74 (left maxillar with P2-M3), BAT10'09.G2-177 (left maxillar with DP2-M2), BAT10’09.G2-123 (left maxillar with DP2-M2), BAT10'07 I4-1 (left hemimandible with p2-m3), BAT10'07 D5-44 (left hemimandible with p2-m3), BAT10'07.D5-22 (right hemimandible with p2-m3),BAT10'11.E3-21 (right hemimandible with p4-m3), BAT10'08.G2-51(left hemimandible with p2-m3), BAT10'10.F2-18 (left hemimandible with p2-m3), BAT10'08.G2-175 (left hemimandible with p2-m3), BAT10'08 G2-183 (left hemimandible with p2-m3), BAT10'13.E4-68 (left hemimandible with p2-m3), BAT10'11.C5-6 (left hemimandible with p2-m3), BAT10'13.E4-80 (left hemimandible with p2-m3), BAT10'13.D4-80 (right hemimandible with p2-m3), BAT10'07.G3-79 (left hemimandible with p2-m3), BAT10'11.D5-40 (left hemimandible with p2-m3),.BAT10'10.F5-9 (right hemimandible with p2-m3), BAT10'12.D6-85 (left hemimandible with p2-m3), BAT10'10.F2-18 (left hemimandible with p2-m3), BAT10 w/n (right hemimandible with p2-m3), BAT10'07.superficie (left hemimandible with p2-m3), BAT10'08.G2-167-168 (right hemimandible with p2-m3), BAT10’13.E2-69 (right and left hemimandibles with p2-m3), BAT10'09.F4-59 (right hemimandible with dp2-m2), BAT10'08.H4-13-14 (left hemimandible with dp2-m2), BAT10'09.F4-22 (left hemimandible with dp2-m1). The rest of the abundant cranial and postcranial material is listed in the S1 and S2 Tables.

Ossicones.

The skulls have two pairs of ossicones (Figs 3 and 4). The smaller anterior pair is located above the orbits on the frontals. It is anteriorly oriented forming an angle with the skull roof of approximately 60°. Its surface has no ridges. The larger posterior pair is located posterior to the orbits over the parietals and is oriented posteriorly and slightly outwards, with and angle to the skull roof between 48–58°. The posterior ossicones are curved, ornamented by a high number of ridges on their surface, which run longitudinally from the base to the tip of the ossicone. The tips are blunt. We found detached complete ossicones and all show a hollow base. We find two distinct morphotypes depending on the size and development of the ossicones. Morphotype I (BAT10’08.G3-91, BAT10'09.F3-102, BAT10'08.F1-112, BAT10'07.S1) (Fig 4) shows a lower development of the ossicones, with the anterior ossicones reduced to unattached little circular disks with a pointy projection in the middle and slenderer posterior ossicones covered in ridges. They loosely resemble the bony spurs found in some Hyemoschus individuals [1], though in the case of the giraffids from Batallones these frontal ossicones are always present, in the same location and with the same structure and morphology. Posterior ossicones in morphotype I range from 225 mm to 270 mm All of the morphotype I ossicones that are attached to a skull are accompanied by adult dentition. Morphotype II (BAT10’13.E2-69, BAT10’07.G4-127, BAT10'16.D4-53BAT10’16.D4-20, BAT10´13.D5-16, BAT10'07.G3-9, BAT10’09.F2-97) (Figs 4 and 5) shows a higher development in both anterior and posterior ossicones. The distance between the bases of the anterior and posterior ossicones in morphotype II doubles that of morphotype I (~80mm vs ~40mm). The anterior ossicones reach 65 mm of length and the posterior 390 mm. The posterior ossicones are more robust and show very deep ridges on their surface. Some specimens have bumps, mainly located over the dorsal surface, although they can also appear laterally (Fig 6) (See S1 Table from measurements). The largest bump is always located on the middle of the dorsal surface, at a similar height on the right and left ossicones (observed in the same individual). This agrees with Solounias [80] who stated that this small irregular protuberances have a somewhat fixed position, suggesting a genetic basis. There is variability between individuals, with some specimens showing a larger number of bumps. According to Harris [81] the disparity in size and development of the bumps may represent individual variability, but it is also possible that the amount of secondary bone apposition, in the form of ornamentation, may be a function of the age of the individual. The surface of the ossicones is very porous, similarly to the surface of the ossicones of extant Giraffa. This may indicate that even with their large size they were covered in hair, irrigated by the cornual artery [82].

Upper dentition.

The DP2 (Fig 9A) is longer than wide, and shows a strong buccal cone. The only two recovered belong to the same individual and are highly worn out (Fig 9A). The DP3 (Fig 9A) is bi-lobed, slightly molarized, and also longer than wide. The anterior lobe is longer and the posterior lobe is shorter and wider. It has a highly developed mesostyle and the parastyle is weak. There is a lingual cingulum. The internal wall is complete. The DP4 (Fig 9A) is molariform with strong paracone and metacone. The meso and parastyles are equally well developed. Both the protocone and metaconule have a rounded lingual border.

The P2 (Figs 3, 4 and 8A) is longer than wide. The buccal cone is strong and closer to the anterior style. The anterior style is more developed than the posterior style, which is barely developed in most specimens. However, this is not the case of BAT10’10.F3-64 where the posterior style is very developed and projects anterobuccally. The anterior style is straight and also very strong, but less than the anterior style. The P3 (Figs 3, 4 and 8A) is longer than wider. It has a strong and pointy buccal cone, closer to the anterior style, and a moderate anterior style. In most specimens the posterior style is barely developed except in BAT10’10.F3-64 where the posterior style is thicker than the anterior style. It is shorter in height than the anterior style and projects anterobuccally. On the posterior part of the medial notch there is a spur protruding from the posterobuccal crista to the posterolingual crista that shows different degrees of wearing. In the most worn out specimens it connects the two posterior cristas (BAT10’10.F3-64, BAT10’08.G1-45). The P4 (Figs 3, 4 and 8A) is wider than long. The buccal cone is moderate and closer to the anterior style. The anterior style is moderate, thicker than the posterior style. The lingual face is simple, with a half-moon shape and in some specimens there is a weak posterolingual spur and sometimes also a weak posterobuccal spur (BAT10’13.E4-74). The M1 (Figs 3, 4 and 8A) has a buccal wall with stronger parastyle and mesostyle and a much weaker metastyle. The paracone is very strong, and the protocone and metaconule are lingually V-shaped and are well separated, with the posterior lobe slightly wider than the anterior one. The enamel is very rugous. There is metaconule-fold. The M2 (Figs 3, 4 and 8A) is similar to the M1, but larger. The M3 (Figs 3, 4 and 8A) has a hypsodoncy index (height/length in an unworn specimen) between 0,78–0,80 (N = 3). It is very similar to M1 and M2 but it shows a very pointy metaconule (BAT10’13.E4-74) and the metacone in unworn specimens is rounder than the paracone (BAT10’08.F4-49). Also buccally there is a small basal pillar next to the mesostyle in two of the specimens (BAT10’13.E4-74, BAT10’10.F3-64). Finally in BAT10’13.E4-74 there is a spur at the pre-protocrista, similar to the metaconule fold. The length/width index (L/W) mean values of the upper molars are 1.12 (n = 34), similar to those of most of giraffids (~ 1.024, n = 810).

Lower dentition.

The bi-lobed lower canine (Fig 10) has a large rounded anterior lobe larger than the posterior one. The larger anterior lobe is rounded and has a thin depression along the midline. The smaller lobe is more pointed and has a posterior small crest that slightly projects buccally. The deciduous canine (Fig 10) has the anterior lobe only slightly larger than the second lobe. The anterior lobe is rounded, whereas in Giraffa camelopardalis and Okapia johnstoni is pointed. The posterior lobe is pointed and triangular in shape. The incisors (Fig 10) are wide and have a straight crown, and are morphologically similar to those of Giraffa camelopardalis and Okapia johnstoni. The deciduous incisors are smaller versions of the adult ones.

The dp2 (Fig 9B) is a simple tooth with no morphological variability. It is smaller than the p2 but morphologically very similar to it. It has a strong mesobuccal conid, separated from the posterolingual and posterobuccal conids. The dp3 (Fig 9B) is elongated, with a larger anterior lobe and a smaller posterior lobe. The anterior stylid is present. The mesobuccal conid is strong and coniform. The posterolingual conid joins the posterobuccal conid, creating a posterior notch. There is an antero-buccal cingulid. The dp4 (Fig 9B) has three lobes, being the most anterior one smaller than the posterior. There is small basal pillar between each lobe. The lingual wall has a moderately developed metastylid. The similarly sized metaconid and entoconid are aligned. The buccal wall has a well-developed protoconid and hypoconid.

The p2 (Fig 8B–8D) is a simple tooth with no morphological variability (N = 21). The anterior conid is strong and there is no anterior stylid. The strong mesobuccal conid is separated from the posterolingual and posterobuccal conids. The p3 (Fig 8B–8D) always has an anterior stylid. The posterolingual and posterobuccal conids are separated. They run parallel in the buccal side and connect lingually. The mesolingual conid is absent and the mesobuccal conid is strong and coniform. There are four distinct p3 morphotypes in D. rex: morphotype I has a slightly bifurcated posterolingual conid (morphotype I, 47,61% n = 10, N = 21); morphotype II shows a simple posterolingual conid (morphotype II, 33,33% n = 7, N = 21); morphotype III has a posterior lingual conid just next to the posterolingual conid but more lingually positioned and about the same height (morphotype III, 14,28%, n = 3, N = 21); finally morphotype IV has an almost complete lingual wall (morphotype IV, 4,76%, n = 1, N = 21). Most specimens belong to morphotypes I and II. Fig 11 shows these morphotypes as well as the occlusal views of the p3 of the rest of the giraffids in this work (Fig 11N). The p4 (Fig 8B–8D) is molarized, with a large anterior lobe that represents two thirds of the tooth length. The mesobuccal and mesolingual conids are strong and coniform. The posterolingual conid is diagonal or aligned to the mesolingual conid, and is attached to the posterobuccal conid. The posterobuccal conid is slightly bifurcated. There is a strong incision on the buccomedial wall between the posterobuccal and mesobuccal conids. There is a small medial valley. In the anterior side of the lingual wall there is a fold that starts on the anterior side of the preprotocristid and reaches the lower part of the lingual wall at the metaconid level. The second lobe is expanded (posterior length/ total length*100) with an average of 36,62% (N = 16) [10].

The lower molars (Fig 8B–8D) have a lingual wall with a moderate metastylid. The metaconid and entoconid are aligned and similar in size. The buccal wall has a well-developed protoconid and hypoconid. In the anterior side of the lingual wall there is fold that starts on the anterior side of the preprotocristid and reaches the lower part of the lingual wall at metaconid level. There is a buccal basal pillar between the anterior and posterior lobes with a variable degree of development, but always larger in the m1. The m3 has a large third lobe, formed by a strong semicircular hypoconulid in lingual position. The semicircular hypoconulid is attached to the posterior side of the hypoconid and entoconid. In most specimens there is a lingual pillar between the hypoconulid and the entoconid, next to the postentocristid and the posterior notch (e.g. BAT10'10.F5-9), although it is not present in others (e.g. BAT10'12.D6-85).

Atlas.

The atlas (Fig 12) has a cranio-centrally positioned and poorly developed dorsal tubercle on the dorsal arch. The cranial margin of the dorsal and ventral arches is C-shaped. The interarticular indentation is thin. The margin of the dorsal arch terminates on the same plane as the margin of the ventral arch. In lateral view, the alar wing is thin and slightly sigmoid shaped. The ventral tubercle is a posteriorly positioned triangular bulge that protrudes caudally.

Axis.

The spinous process is well-developed, often massive and triangular in shape (Fig 13). In dorsal view, the spinous process is caudally thicker than cranially, slightly arched and inclined cranially. The cranial edge of the spinous process is caudally positioned to the cranial edge of the dens. The dens is dorsally concave and has a rounded cranial end. In its most cranial part there are two rounded lateral concave depressions separated by a bony bulge. The cranial opening of the foramen transversarium is very wide. The caudal articular facets are oval shaped and protrude laterally. The transverse process protrudes laterally and the caudal indentation is semicircular. The ventral ridge is thin and continuous throughout the length of the vertebral body, thickening caudally and protruding more caudally than the caudal vertebral fossa.

Cervical vertebrae.

In dorsal view, the spinous process is situated between the base of the cranial and caudal articular processes, in the middle of the dorsal vertebral body (Fig 14). It is elongated and bulgy and is directed dorsally. The spinous process extends by the majority of the length of the dorsal vertebral body. One distinct ridge radiates from the caudal aspect of the spinous process onto the dorsal lamina. The cranial articular facets are oriented dorsomedially and are rounded. The cranial bulge is convex and oval shaped. The tip of the cranial bulge protrudes over the cranial articular processes. The cranial articular process and facet extend cranially to the same level as the tip of the cranial bulge. In lateral view, the ventral tubercle of the transverse process extends cranially, extending further than the cranial bulge tip. The dorsal tubercle of the transverse process forms a wing that protrudes laterally and connects to the caudal part of the ventral tubercle of the transverse process. The caudal aspect of the vertebra is about the same size of the cranial part. The caudal articular facets are rounded. In ventral view, the cranial end of the vertebra is narrower than the caudal end. The ventral ridge is prominent and continuous longitudinally on the vertebral body. C3s are slightly shorter than the axis and more elongated than the rest of the cervical vertebrae (C4 to C7) that gradually become shorter and wider, while the spinous processes become shorter and higher.

Thoracic vertebrae.

In cranial view, the cranial bulge is triangular (Fig 15). The cranial articular processes are oval shaped and are located slightly anteriorly than the tip of the cranial bulge. In dorsal view, the spinous process is located posterior to the cranial articular processes and is oriented dorsocaudally. It is thicker at the base, becoming thinner towards the top. The spinous processes width is constant along their length. Their height increases suddenly from T1 to T2, reaches a maximum at T2—T4, and then decreases like in the giraffe [85]. The first spinous processes are almost vertical, the T4—T7 segment presents a slight caudoversion, which disappears at the last vertebrae, which are vertical[85]. The transverse processes are thick and protrude laterally and are located exterior to the cranial articular processes. The caudal articular processes are oval and oriented ventrocaudally. In ventral view the ventral crest of the body is cranially bulgy. There is variability in the orientation of the caudal articular processes. In BAT10'08.D5-10 they are ventro-caudally oriented while in BAT10’07.superficie they are completely ventrally oriented. This also indicates a change in the angle of the spinous process, more vertical in BAT10'08.D5-10 and more caudal in BAT10’07.superficie. This is probably due to the more anterior position of BAT10'08.D5-10 and hence the inclination of the process augments proportionally with the relative position of each thoracic vertebra. This is also reflected in the orientation of the cranial articular processes, that is more craniodorsally-oriented in BAT10'08.D5-10 and more dorsally-oriented in BAT10’07.superficie.

Lumbar vertebrae.

The cranial bulge is heart-shaped (Fig 16). The spinous process is located posterior to the cranial articular processes and the mammillary processes. The shaft of the spinous process is dorsally oriented and shows a slightly rugged surface towards the upper part indicating the insertion for the multifidus muscle. The top part of the spinous process projects cranially. It is bulgy, thick and rugous indicating a strong insertion for the wide dorsal muscle and the longissimus and spinous lumbar muscles. The medially oriented cranial articular processes are rounded and curved, and protrude further than the tip of the cranial bulge. The mammillary process is bulgy and has a very rugous surface indicating a strong insertion for the multifidus, longissimus and spinous muscles. The transverse processes are thin and protrude craniolaterally showing in some cases a sigmoidal curvature. They are located exterior to the cranial articular processes. The caudal articular processes are rounded. Some caudal articular processes show half of the circular facet oriented ventrolaterally and the other half oriented cranially (e.g.BAT10'13.D4-40, BAT10. SN). Other specimens show half of the circular facet oriented ventrolaterally and the other half oriented laterally, with a concave surface (BAT10'08.G4-119, BAT10'09.G5-25). In ventral view the ventral crest of the body bulges cranially and the surface of the vertebral body is rugous showing a strong insertion for the diaphragm and the psoas minor muscle. Regarding variability, the L3 BAT10’14.E1-2 shows a spinous process with a curved posterior outline for ¾ of the shaft and a slightly longer spinous process than the rest of the lumbars. Compared to the L3 the L4 BAT10’14.E1-3 has a straighter outline of the posterior spinous process, and the L5 BAT10’14.E1-4 shows a stronger and wider dorsal part of the spinous process. Also its spinous process is wider and a shorter than those of the rest of the lumbars. The transverse process is longer and distally thinner than the transverse process of the other lumbars.

Caudal vertebrae.

We recovered eleven coccygeal vertebrae from the same individual (Fig 17) (BAT10’14.E2-28, BAT10’14.E2-29, BAT10’14.E2-30, BAT10’14.E2-31, BAT10’14.E2-39, BAT10’14.E2-40, BAT10’14.E2-47, BAT10’14.E2-48, BAT10’14.E2-s/n a, BAT10’14.E2-s/n b, BAT10’14.E2-s/n). The first three coccygeal vertebrae are more robust and larger (BAT10’14.E2-28, BAT10’14.E2-29, BAT10’14.E2-30). The vertebral head is pentagonal and the vertebral body is elongated. The hemal process is only slightly developed. The mammillary processes are thin and latero-ventrally oriented. The transverse processes are thin and protrude laterally. There is a gradual size reduction in the absolute length of the vertebral body from the first to the last coccygeal vertebrae. The transverse processes also get reduced, totally disappearing at the fourth vertebra. The mammillary processes also get smaller, disappearing in the last three vertebrae.

Ribs.

The tubercle border has a tear-drop shape. The neck is short and concave. The head has two rounded facets on the medial and lateral sides. There is a tuberosity for the longissimus muscle. On the cranial border there is a rugous surface for the iliocostal muscle. The costocondral articulation is wider than the ventral extremity of the rib.

Scapula.

In lateral view the glenoid cavity is rounded with a thick border (Fig 18). The supraglenoid tubercle is very developed and rugous indicating strong biceps brachii muscle as well as supraspinous muscle. The acromion is developed and rugous. The scapular spine is developed and rugous, disappearing towards the end of the scapula, indicating a strong trapezius and deltoid muscles. The infraspinous fossa and the supraspinous fossa are triangular. The infraspinous fossa has a strong rugous border, especially on the caudal angle indicating strong insertions for the triceps brachii long head muscles.

Humerus.

The apex of the tuberculus major is caudally massive and curves medially indicating a strong supraspinatous muscle (Fig 19A–19F). The tuberculus major is large and very developed with a very rugged surface for the insertion of the deep infraspinatous muscle. The tuberosity for the teres minor is also developed and has a rugous surface. The deltoid tuberosity for the deltoid muscle is moderately developed. The apex of the tuberculus minor is developed and rugous, indicating the insertion for the subscapularis muscle. The convexity of the minor tubercle is semicircular. The humeral head is rounded and has a smooth surface. The area below it is slightly rugous, indicating the insertion of the brachialis muscle. The insertion for the teres major is present as a depression on the medial side. The olecranon fossa is triangular and deep. The lateral and medial epicondyles have very rugous areas caudally and there are also some small tuberosities on the lateral side of the lateral epicondyle for the insertion of both the extensor digitorum communis muscle and the extensor carpi radialis muscle. On cranial view there is a very rugous area right above the capitulum indicating a very strong extensor indicis musle and the extensor digitorum communis. There is also a bulgy rugous area in the diaphysis for the pectoralis descendens muscle.

Radius / Ulna.

In dorsal view the dorsoproximal coronoid process is pointed (Fig 19G–19L). The proximal facets for the ulna are well preserved. The lateral one, smooth and semicircular, is located in a moderately developed pit. The smaller and triangular medial facet does not touch the lateral one. In proximal view, the medial half of the humeral articulation facet is dorsopalmarly and lateromedially wider than the lateral half. The lateral border of the capitulum facet is more or less straight. The groove for the lateral lip of the distal trochlea of the humerus is wide and moderately deep. There is a soft step between the capitulum facet and the rest of the proximal joint. The lateral tuberosity for the insertion of both the flexor digitorum superficialis muscle and the lateral extensor digitorum communis muscle is highly developed. The dorsal groove for the extensor carpi radialis muscle is wide and very shallow, curving towards its distal part. The crests that limit the dorsal groove show a similar development. On the lateral surface the groove for the extensor digitorum lateralis muscle is clearly marked but shallow. Distally, the scaphoid facet is palmarly convex and dorsally concave, and almost oval in shape. Its dorsal contour is more irregular than that of the semilunate facet, which is completely semicircular. The semilunate facet is palmarly convex but flattens dorsally, and its lateral and medial crests reach the palmar side of the radius forming a groove. The triquetrum facet is flatter and its dorsal border is semicircular. The dorsal border of the olecranon is convex and the palmar border is slightly concave. The olecranon tuberosity is strong. The styloid process is well developed.

Scaphoid.

In medial view the dorsal border is straight (Fig 20A–20F). The proximo-palmar process is wide and blunt and it is placed almost at the same level than the dorsal process. The palmar outline shows a proximal bulge. On the disto-palmar area there is a small projection with no articulation facet that in bovids and cervids sports another facet for the semilunate. The proximal side is wide, with a sinuous surface, being dorsally convex and turning palmarly concave. The distal articulation for the magnotrapezoid is wide.

Semilunate.

The proximal facet is concave, with dorsal and palmar bulges (Fig 20G–20L). The dorsal facet is dorsally wider than the distal facet, while the distal facet is palmarly wider than the proximal facet. The proximomedial facet for the scaphoid is complete and straight while the distomedial facet is rectangular and is only dorsally present. In lateral view the dorsoproximal facet for the triquetrum is triangular and wide, and the distopalmar facet for the triquetrum is semicircular. The distal facet for the hamatum is narrower than the magnotrapezoid facet. The keel between these two facets is blunt and the posteropalmar area shows an acute concavity.

Triquetrum (Os carpi ulnare).

In lateral view the dorsal profile is slightly concave (Fig 20M–20R). The distopalmar process is thick and well developed. The profile of the distal facet is concave. The pisiform facet is subrectangular with soft rounded corners (almost oval). In dorsal view, the proximal facet for the semilunate is developed and rounded. On the medial surface the central facet is large and subtriangular. The well-developed central knob placed behind this facet is slightly connected to it. The internal facet of the distal process is semicircular in shape.

Pisiform.

In lateromedial view the pisiform has an asymmetric contour (Fig 20S–20W). The dorsal border is rounded and convex, and the palmar area is thick. The dorsal facet for the triquetrum is pear- shaped and transversely thick.

Magnotrapezoid.

In proximal view the magnotrapezoid has an almost square shape (Fig 21A–21F). The edge between the proximal facets for the scaphoid and the semilunate shows an inflection of ~130°. The lateral facet for the semilunate is narrower than the facet for the scaphoid. The outline of the palmar border is nearly straight. The wide facet for the hamatum reaches the distal surface, extending proximally towards its palmar side. There is a small groove for ligament attachment in the distopalmar end of the medial surface. In palmar view the border for the scaphoid facet shows a medial elongation towards the distal face.

Hamatum.

The proximal surface is semicircular and shows two distinct facets (Fig 21G–21L). The proximal facet for the triquetrum is broad, lateromedially concave and wider than the facet for the semilunate. Medially there is only one scythe-shaped continuous facet for the magnotrapezoid, that extends palmarly. The lateropalmar process is well developed, slightly surpassing the distal edge of the distal facet.

Metacarpal III-IV.

The metacarpals are relatively robust compared to Decennatherium pachecoi, with a robustness index (RI) that ranges from 10,58 to 12,76 [86]. The proximal articular surface is semicircular, with the sub-quadrangular facet for the magnotrapezoid occupying more than 2/3 of the available area (Fig 22). The hamatum facet is triangular in shape. The keel between both facets is well marked and thin. Both the hamatum facet and most of the lateral part of the magnotrapezoid facet extend palmarly. The oval synovial fossa is well developed and closed. The diaphysis widens distally. The central groove on the diaphysis dorsal surface is very shallow, almost imperceptible. The dorso-proximal tuberosity where the tendon of the extensor carpi radialis muscle is inserted is well developed. In lateral position the sulcus for the lateral extensor tendon is short. On the proximal end of the palmar surface there is a rugous area where the interosseous muscles and the flexor carpi radialis muscle insert. The proximal areas of the palmar ridges are rugous. There is a central palmar concavity on the diaphysis called posterior trough [1]. This trough is shallow, extending approximately two-thirds down the shaft length. The distal joints are proportionally short and wide, and the keels are dorsally poorly developed, turning slightly sharper palmarly. The inter-trochlear incision is wide but its shape is not discernible due to the presence of sediment between the two trochleas. In lateral view the dorsal part of the distal articular surface is rounded (not flattened). The internal articular surfaces of the pulleys are wider and more rectangular than the external ones. In the specimen BAT10’09.G2-81 there is a noticeable difference between the two distal trochleas. The lateral one extends further distally than the medial trochlea, placing the distal articulation surface at two different levels, the lateral lower and the medial higher. This disposition may be interpreted as an osteological pathology, possibly being caused by a fracture during this individual’s life.

Pelvis.

The ischiatic tuberosity is very developed and bulgy, especially in the attachment area for the semitendinous muscles (Fig 23). The region of attachment for the gluteo-bideps/femoral biceps mucle is rugous. The ischium body is wide and the sciatic spine is not very developed. The branch of the ischium is thin but has a strong pubian spine for the pectine muscle. The obturator foramen is rounded. The acetabulum is rounded and deep, with a thick border. The acetabulum fossa is rounded and the acetabular incision is very thin. The semi-lunate fossa of the acetabulum is soft and C-shaped. The insertion surface for the right muscle of the cuisse is rugous. The ilium neck is wide but short. The ilium is large and highly expanded with a developed dorsocranial spine and an even larger ventrocranial spine.

Femur.

Proximally, the apex of the great trochanter is moderately developed, with a rugous surface for the gluteus medium muscle (Fig 24A–24F). The crest of the great trochanter, where the broad lateral muscle inserts, is very developed and highly rugous. The femur head is rounded. The neck of the femur is concave and rugous. The small trochanter is also very developed and rugous, showing a strong insertion for the broad medial muscle. Caudally, the intertrochanteric crest is very thick and strong, and the trochanteric fossa is oval and deep. The medial and lateral condyles are asymmetrical, being the lateral condyle larger than the medial. The intercondylar fossa is deep. Medially, the trochlear tubercle and the medial lip of the trochlea are large and bulgy. Medially, the medial epicondyle has a rugous surface. There is a rugous tuberosity for the gastrocnemius and semimembranosus muscles above the medial epicondyle. There are two lateral fossetes, one for the popliteal muscle and the larger more ventrally positioned for ligament insertion.

Patella.

The patella is triangular and cranially broad (Fig 24G–24L). On the lateral side it has a crest for the fascia lata and a very rugous and bulgy area for the insertion of both the gluteofemoral muscle and the broad lateral and broad intermediary muscles. On its dorsal side there is a rugous area for the articular knee muscle. Caudally, the articular surface for the femur is subquadrangular in shape.

Tibia.

In dorsal view the tibial tuberosity is very developed and rugous in the insertion area for the gluteo-biceps muscle (biceps femoral and fascia lata), and the semi-tendinous muscle (Fig 24M–24R). The intercondylar eminences are well developed. The lateral condyle has an almost straight lateral profile, curving plantarly. The medial condyle is almost semicircular, with a rounded medial outline and a rugous area indicating the insertion of the semi-membranous muscle. The popliteal fossa forms an acute concavity. The diaphysis is robust, with a flat dorso-distal surface that confers a quadrangular shape to the cross section of this area. Dorsally the tibia lacks a medio-distal crest. The distal epiphysis is better preserved. In dorsal view the central protuberance is relatively wide and well developed. The dorsal border of the protuberance is straight and placed at a lower level than the medial malleolus. In dorsal view the facet for the fibula is located on the lateral side of the tibia distal border. The medial malleolus is strong, narrowing distally. On the plantar side the groove for the tendon of the flexor digitorum longus muscle and the tibialis caudalis muscle is wide and shallow. The distal plantar surface is moderately convex. In distal view the astragalus articulation (distal cochlea) shows an asymmetric contour, being more developed medially than laterally. The medial half of the distal cochlea is narrower and deeper than the lateral half. The plantar facet for the fibula is concave and bigger than the dorsal facet.

Fibula.

The outline in lateral view is rectangular or subtrapezoidal, with the dorsal border flatter than the plantar border (Fig 24S–24X). The proximal spine is strong. It is slightly displaced plantarly, and well separated from the dorso-proximal angle. The dorso-proximal angle is located at the same high or slightly below the proximo-plantar angle.

Calcaneum.

The dorsal outline of the calcaneum body is straight or slightly convex (Fig 25A–25F). The plantar border is somewhat concave, widening and forming a bump just above the distal end. The plantar surface of the calcaneum body is thick and rough. The proximal and lateral prominences for tendinous insertion of the tuber calcanei are strong. In dorsal view they can reach the same height or the lateral prominence may be more developed than the lateral one. In proximal view the tuber calcanei contour is typically heart-shaped clearly showing the plantar groove and the transversal rim of the insertion area for the gastrocnemius muscle. The sustentaculum tali has a convex proximal border and a rounded and concave distal border. In the distal area of the lateral surface there is a very thickened and bulky area that occupies most of the dorsal part. Farther back of this protuberance a groove-like depressed area can be appreciated. The prominent fibula facet is divided into a larger proximal convex facet and a distal one shorter and slightly concave. The distal facet for the astragalus is long and its dorsal border is inclined.

Astragalus.

In dorsal view the proximal trochlea is longer than the distal one, which is typical of giraffids and can be appreciated in Giraffa camelopardalis and Okapia johnstoni. (Fig 25G–25L). Their medial and lateral borders are straight and parallel, aligned with the borders of the distal trochlea. The lateral lip of the proximal trochlea is thicker than the medial lip. The gorge of the proximal trochlea is wide and the central fossa is very deep. The central projection of the medial border is well developed and blunt. The gorge of the distal trochlea is shallow. The medial lip of the trochlea is shorter than the lateral one and has a more rounded distal border. The proximoplantar prominence is thick and more or less projected in all the specimens. The fossa located in the distal area of the medial surface is relatively deep. In lateral view the central surface of the bone is convex, with an ample fossa on the distal side that has a rough surface. The distal facet for the calcaneus is centered or only slightly displaced relative to the proximodistal edge of the astragalus, and shows a semicircular or kidney-shaped profile. The plantar facet for the calcaneus has a small central concavity, and its medial border is slightly curved.

Navicular-cuboid.

The proximal articulation for the astragalus is subrectangular (Fig 25M–25R), with a shallow plantar fossa between its two halfs. The lateral facet for the calcaneus is long and wide, almost reaching the dorsal border of the bone. In medial view the plantar border is irregular. There is a distal step between the dorsal facet for the ectomesocuneiform and the facet for the entocuneiform. In lateral view there is a distoplantar tuberosity and an insertion groove for the peroneus longus muscle that is moderately wide and well-marked in all the specimens. The laterodistal tuberosity is moderately developed. The dorsal facet for the metatarsal is oval and has a small medial inbound. The medial facet for the ectomesocuneiform is kidney-shaped. The facet for the entocuneiform is convex an oval. On the plantar side there is well-developed proximo-plantodistal process. On this process there is an inclined crest that that extends through all the plantar surface. Lateral to this crest there is a well-developed semicircular canal.

Ectomesocuneiform.

All the ectomesocuneiforms are similar in size, proportions and morphology, and resemble those of extant giraffids. However, in Okapia all the cuneiforms are fused to the navicular-cuboids, and in Giraffa the ectomesocuneiforms and the entocuneiforms are also fused forming a single piece. In proximal view the general contour of the ectomesocuneiform is sub-elliptical (Fig 26A–26F). The surface of the proximal articulation is concave. In the lateral surface the dorso-proximal facet is elongated, semicircular and variable, being bigger in BAT10’12.D5-53 and BAT10’09.F2-40 and smaller in BAT10’12.D6-130. The distal facet for the metatarsal is kidney-shaped, slightly dorsally convex and plantarly flat.

Entocuneiform.

This bone is proximodistally as tall as the ectomesocuneiform (Fig 26G–26L). In dorsal view they show a protuberance on the plantodistal margin that is stronger in BAT10’12.D6-130. In proximal view the articulation facet for the navicular-cuboid is flat and shows a teardrop-shape. The medial surface is flatter than the lateral one. This surface sports a depression. In distal view the articular facet with the metatarsal is wide and oval-shaped.

Metatarsal III-IV.

The metatarsals are medium in robustness relatively to other giraffids, with a robustness index (RI) that ranges from 8,69 to 10,33. They are more slender than the metacarpals. In dorsal view there is a small step between the medial and lateral proximal facets, located at slightly different levels (Fig 27). The common digital artery runs superficially on the dorsal surface of the metatarsal III-IV within a canal (the metatarsal sulcus) that is distally open. This condition of the common digital artery is classified as “moschid-type”[87], meaning that it is superficial but not as superficial as in derived bovids. The metatarsal sulcus is proximally shallower and distally deeper. The proximal canal for the extensor digitorum lateralis is broad. On the plantar side there is a proximocentral fossa that appears to be deeper in BAT10’09.D5-53. In the three specimens a plantar concavity can be observed on the proximal part of the diaphysis. This concavity is shallow and disappears distally, where the plantar surface is flat. In proximal view there is an asymmetry between the lateral and the medial profile. The kidney-shaped articulation facet for the ectomesocuneiform is similar in size to the navicular-cuboid facet, which is semicircular. The entocuneiform facet is relatively big and teardrop-shaped and it stands out over the plantar profile. The metatarsal broadens distally on the last fifth of the bone. The distal trochleas are wide and low and the keels are plantarly narrower and thinner. The dorsal profile of the distal end of the diaphysis is slightly convex. The keels do not extend plantarly into the shaft.

Lateral metapodials II and V.

Metapodials II and V are very reduced (Fig 28). Located proximomedially, next to the metapodial III-IV but not attached to it, they can be recognized as a thin and elongated tubercle between the medial cuneiform facets. There are specimens that only preserve the proximal thicker part (e.g. BAT10’12.D6-97) while others are composed of a proximal part and a more distal part (e.g. BAT10’12.D6-108). The proximal part is rugous and thicker than the thin and stylet-shaped distal part. The complete lateral metapodials do not represent more than 1/8 of the total metatarsal III-IV length.

Metatarsal sesamoid.

The only one preserved attaches to the dorsoventral surface of the metatarsal in a central position. It is rugous and ovoid shape (Fig 27).

First phalanx.

In dorsal view the first phalanges resemble a cone, wider in the proximal part, and narrower distally (Fig 29A–29E). In both lateral and dorsal view, the first phalanges are transversally wide, with strong proximal and distal ends, resembling type A of Köhler in having athe facet of the distal articulation being visible from the dorsal side, and type C in having a stronger proximal end [88].The proximal articular surface is transversally wider than the distal joint. In proximal view proximal facet is heart-shaped and asymmetric, with the inter-digital half shorter and with a rounded profile and he lateral half longer and with a straight border. The central groove is not too deep and it is relatively wide. On the palmar/plantar surface there are two long and rugous bulges with a sulcus between them, more or less deep depending on the specimen. These bulges represent proximal areas for ligament insertion, where the collateral and the sesamoid ligaments, as well as the interosseous muscle tendon attach. The interdigital surface also shows some rugous areas for the interdigital ligament, although this surface is almost even, suggesting than it was not very strong. The outline of the dorsal surface is flat or slightly concave. The distal articulation is well rounded from its lateral aspect and its facet is not visible form the dorsal view. The concave palmar/plantar curvature begins from the middle of the shaft. The distal joint is trapezoidal and asymmetric with the lateral half almost twice wider than the inter-digital one. Two groups of phalanges can be differentiated according to their general dimensions. We analyzed the autopodium of a complete connected specimen and it appears that longer phalanges may be interpreted as anterior phalanges, and the shorter as posterior phalanges but there are no critical morphological or metrical differences between them. This homogeneity agrees with that observed in the related measurements of the distal epiphyses of both metapodials in particular those of the pulleys.

Second phalanx.

In both lateral and dorsal view, the second phalanges are very robust and transversally wide, with strong proximal and distal ends (Fig 29F–29J). The proximal articular surface is transversally wider than the distal joint. In proximal view the joint for the first phalanx is sub-quadrangular in shape. The proximal articular surface is slightly concave and the crest that divides the two articulation sides is soft. The post-articular platform is proximally elongated and the dorsal extensor process is prominent and rugous. Proximally, the impressions for the origin of the interdigital (or cruciate) ligaments and the insertion of the flexor tendon are weak. The dorsal extensor process is high and rugous. The distal articular surface is triangular and asymmetric, with a reduced inter-digital part.

Third phalanx.

In both lateral and dorsal view, the third phalanges are long and transversally narrow (Fig 29K–29S). From a lateral view they show a triangular outline. There is a well-developed dorsal process for the insertion of the extensor digitorum (longus or comunis depending if it is the anterior or the posterior phalanx) that is even more prominent than in Giraffa. The articular facet is rounded, with the exterior part larger than the inter-digital part. Both are concave and are inclined towards the inter-digital side of the phalanx. There is a moderately strong plantar process for the insertion of the deep flexor tendon. There is a small rhomboidal facet for the distal sesamoid. The plantar surface of the phalanges has the shape of an isosceles triangle.

Sesamoids.

The proximal exterior and larger sesamoids show facets for the metapodial semicircular and proximodistally shorter (Fig 30A–30F), while the interdigital ones are elongated and oval (Fig 30G–30L). They also differ in the size, being the interdigital sesamoids dorso-palmarly/plantarly taller. The distal sesamoids show two facets (Fig 30M–30R), both oval in shape. The interdigital one is larger than the lateral.