Middle Miocene to Pleistocene fossiliferous sedimentary rocks in the Sinap Tepe–Beycedere–Kavakdere area, northwest of Ankara, central Anatolia, in the vicinity of the towns Kazan and Çubuk, are part of the Sinap Formation (summarized in Lunkka et al., 2003). The Sinap Formation comprises seven members (Yellidoruk Mb, Lower Sinap Mb, Middle Sinap Mb, Upper Sinap Mb, Beycedere Mb, Kavakdere Mb, Igbek Mb: see Fig. 1.3 in Lunkka et al., 2003). The basal and oldest member is the Beycedere Mb. It is overlain by the Lower to Upper Sinap Members and the contemporaneous Igbek Mb. The upper units of the Sinap Members and the Igbek Mb overlap the lower part of the successive Kavakdere Mb. All these members are of middle to late Miocene age. The following Çalta Mb is of late Miocene to Pliocene age (see Fig. 1.3 in Lunkka et al., 2003). Outcrops or sections in the Sinap Tepe–Beycedere–Kavakdere area are grouped according to their geographic position into three subareas: 1) Sinap Tepe (incl. the sections Yellidoruk I, Yellidoruk II, Delikayincak Tepe, and Sinap I to VI), 2) Igbek (incl. the Igbek section), and 3) Beycedere–Kavakdere (incl. the sections Beycedere, Kavakdere S, Kavakdere N). Sections in the Sinap Tepe subarea are characterized by the Yellidorik and Sinap Members, magnetostratigraphically correlated as 10.899–9.279 Ma and of early to middle Vallesian age (Kappelman et al., 2003: Koufos et al., 2018). The Igbek subarea is characterized by the Igbek Mb, with an interpolated age of 9.130 Ma and is of late Vallesian age (Kappelman et al., 2003: Koufos et al., 2018). The sections in the Beycedere–Kavakdere subarea are characterized by the Beycedere and Kavakdere Members. These are of early Turolian age, spanning a range from 8.866 to 8.121 Ma (Kappelman et al., 2003: Koufos et al., 2018). The giraffid collection described herein was collected from the upper units of the Kavakdere N section (Kavakdere Mb, see Fig. 1.7 in Lunkka et al., 2003). This horizon is equivalent to Loc. 26 of the latest Sinap Project, conducted by Prof. B. Alpagut during the years 1989–1995 (Kappelman et al., 2003 and Sen, 2003). The sedimentary rock section at Kavakdere N is dominated by silicified mudstones interbedded with marly sediments in the lower part and coarser units in the upper half (Lunkka et al., 2003). The fossiliferous horizon was magnetostratigraphically dated to 8.12 Ma by Kappelman et al. (2003).

The fossil giraffid material from AAK is stored in the Natural History Museum of Ege University, Izmir, Turkey (EUNHM). The present study focuses on fossil dental and post cranial material of Giraffidae and its main goal is to update the faunal list of AAK based on this historical collection. All material was measured using an electronic calliper, as well as a measuring tape, for the larger specimens. Measurements are given in millimetres and presented in the respective tables. Width measurements of dental elements were taken on the base of the crown. Statistical analyses were achieved using the software PAST (Hammer et al., 2001). Dental terminology follows Bärmann and Rössner (2011). Anatomical terms of postcranial elements follow Schaller (2007), Solounias and Danowitz (2016a), and Ríos et al. (2016).

Class Mammalia Linnaeus, 1758

Order Artiodactyla Owen, 1848

Family Giraffidae Gray, 1821

Subfamily Sivatheriinae Zittel, 1893

Genus Helladotherium Gaudry, 1860

Helladotherium duvernoyi (Gaudry and Lartet, 1856)

Material: PV-156, distal part of right humerus; PV-155, left radius; PV-33, distal part of left radius; PV-154, right metacarpal; PV-151, left tibia; PV-157, left astragalus; PV-158, right astragalus; PV-237, right naviculocuboideum; PV-152, right metatarsal; PV-159, proximal phalanx; PV-160, proximal phalanx; PV-161, proximal phalanx; PV-162, middle phalanx; PV-163, middle phalanx (Fig. 2; Table 1).

Descriptions: H. duvernoyi is represented only by post-cranial elements of the front and hind limbs. The humerus (PV-156; Fig. 2A) maintains the distal condyle and most of the diaphysis, while the proximal epiphysis is absent. Medially, the teres tuberosity, for the termination of M. teres major and M. latissimus is well pronounced, narrow and long. The crista humeri is blunt and almost not visible. The radial fossa is shallow but well-defined. The fossa olecrani is open and sub-rounded. The lateral epicondyle is strong giving the lateral trochlea a quadrate shape, while the medial epicondyle is weak and blunt. The distal trochlea is asymmetrical with the medial condyle being notably smaller. In cranial aspect, the medial condyle is interrupted by a grove, which is positioned medio-caudally to the keel of the trochlea.

Two incomplete specimens of radii were recovered. PV-155 (Fig. 2B) represents a radius-ulna with the proximal part, as well as a large part of the diaphysis recovered, while PV-33 (Fig. 2C) represents only the distal part of a left radius. In proximal aspect, the medial articular surface is rounded and notably smaller than the lateral one, which shows a sub-quadrate outline. Both surfaces are wide, slightly concave and well limited by an evident and sharp rim. The lateral protuberance is well developed, but not as strong as the radial tuberosity. The diaphysis is simple, with the medial and lateral surfaces running almost parallel to each other. On the distal trochlea and in cranial aspect, the groove for the extensor carpi radialis and the common extensor tendon is wide and shallow. This area is well defined by two strong crests, which run parallel to each other from the medial plane of the scaphoid facet and the medial plane of the lunatum facet until almost the lower 25% of the length of the radius. The lateral styloid process is strong and more developed than the medial one. In distal aspect, the facet for the scaphoid is deep and rounded. The facet for the lunatum is also deep, with crests of the facet being parallel only caudally. The surface for the pyramidal is shallow and semi-circular. On PV-155, a large part of the ulna is also present. The tuber olecrani is strong, extending caudally. The processus anconeus is absent and the processus coronoideus is completely fused with the caudal plane of the head of the radius. The incisura trochlearis is long and wide. The proximal interosseous space between radius and ulna is long. The lateral and medial borders of the corpus ulnae are not visible, due to the strong fusion with the radius.

The metacarpal (PV-154; Fig. 2D) is long and robust. In palmar aspect, the medial and lateral epicondyles seem equally developed. In dorsal and proximal aspects, however, the medial epicondyle is more developed, due to the positioning of the facet for the trapezoideo-capitatum. This facet is almost rectangular, while the facet for the hamatum is sub-triangular. The epicondyles are well separated by the open synovial fossa, which is deep and extends towards the central trough, a common feature in members of the Sivatheriinae. The latter is deep and concave on the upper part of the shaft and flattens gradually towards the head of the metacarpal. The trough is limited by two strong ridges, with the medial ridge being notably sharper than the lateral ridge. The head is flat, and the keels of the distal condyles are strong and sharp in palmar aspect, getting progressively blunter towards the dorsal side.

The tibia is represented by an almost complete specimen (PV-151; Fig. 2E) with the proximal extremity being absent. The diaphysis is simple and slightly bent. In cranial aspect, the shaft is smooth and there is only a small groove noted towards the proximal end of the tibia, which would lead to the extensor groove. Caudally, the shaft is more ornamented, with a very long popliteal line originating from the distal epiphysis and running through the whole shaft, parallel to the weak curve of the tibia. Additional long muscular lines can be seen towards the lateral margin of the shaft. The medial malleolus is strongly developed. In distal aspect, the facets for the astragalus are parallel, with the lateral one being slightly larger.

Two astragali of Helladotherium have been recovered (PV-157, PV- 158; Fig. 2F). In dorsal aspect, the lateral ridge of the trochlea is very strong. The medial ridge is notably thinner, leading to a blunt lip on the medial margin. The medial bulge at the collum tali is fairly developed and rounded. The head is slightly asymmetrical, with the lateral trochlea being somewhat bigger than the medial trochlea. The groove of the trochlea is open, following the slight curve of the lateral ridge. The ventral articular surface is almost square in shape, with the medial margin interrupted by a distinct medial scala. The proximal triangular fossa is deep and well defined. The distal intracephalic fossa is very weak and the medial scala very prominent, a common feature observed in Helladotherium.

The naviculocuboideum (PV-237; Fig. 2G) is large and oval shaped in proximal view. The astragalar facets are parallel, with the lateral one being notably longer. The lateral peak is short and blunt. The calcaneal facet is long and extends almost behind the lateral peak, as in all Sivatheriinae. In distal aspect, the facet for the metatarsal is sub-triangular. The facet for the external cuneiform is almost as big as the metatarsal facet and it is sub-rectangular in shape. The facet for the medial cuneiform is much smaller, oval shaped and well separated from the medial cuneiform facet by a sharp crest.

The metatarsal (PV-152; Fig. 2H) is long and complete, revealing all distinctive features. In proximal view, the facet for the naviculocuboideum is long and is sub-rectangularly shaped. The facet for the external cuneiform is slightly larger and the facet for the medial cuneiform is small and rounded. In plantar view, the epicondyles are all strong and well separated. The dorsal head of the lateral epicondyle is rounded and robust. The ventral head of the lateral epicondyle is broken, and it seems to be as developed as the dorsal head, but less extended laterally. The medial epicondyle is generally stronger and more robust. The ventral head is very strong, leading to the blunt medial ridge of the central trough. The pygmaios is absent. On the distal epiphysis, the keels of the medial and the lateral condyles are strong and equally developed in plantar and dorsal aspect.

The proximal phalanx (PV-159, PV-160, PV-161; Fig. 2I) is robust. The medial and lateral margins of the body are almost parallel to each other, since the base and the head of the phalanx are only slightly extended mediolaterally. On the articular fovea, the medial articular facet is well separated by the larger lateral articular facet by a distinct trough. In lateral and medial view, the palmar tubercles are strong and long, typical for the taxon. The head of the phalanx is asymmetrical, with the medial trochlea being slightly bigger than the lateral trochlea.

The middle phalanx (PV-162, PV-163; Fig. 2J) is short, with an almost flat palmar surface and a strongly convex plantar margin. The palmar tubercles are robust and postero-dorsally extended. The medial and lateral keels of the distal epiphysis are sharp and well-defined.

Comparisons and remarks: Helladotherium duvernoyi constitutes one of the most common large-sized Miocene giraffids. The stratigraphic origin of the earliest collection from the type locality of Pikermi, described by Gaudry (1860), is unknown. Therefore, there is no designated holotype. However, all the sivatheres of the type locality belong to the same species, and therefore, the assignment of a lectotype is unnecessary (Geraads et al., 2005). Helladotherium duvernoyi is the only species assigned to the genus and it appears in several localities of the Greco-Iranian province, from MN9 to MN13 (Athanassiou, 2002, Bonis et al., 1992, Iliopoulos, 2003, Kostopoulos and Koufos, 2006, Kostopoulos and Saraç, 2005, Kostopoulos et al., 2009, Kostopoulos et al., 1996, Kostopoulos et al., 2003, Kostopoulos, 2009, Koufos, 1990, Koufos, 2006, Koufos et al., 2009, Marinos and Symeonidis, 1974, Solounias, 1981a and Solounias, 1981b).

Although in the studied collection dental remains of H. duvernoyi are completely absent, a collection of fore and hind-limb specimens can clearly distinct this taxon from other large Miocene giraffids, such as Samotherium Forsyth-Major (1888) and Bramatherium Falconer (1845). Morphological differences of post-cranial elements of H. duvernoyi, Samotherium boissieri, S. major and Bramatherium megacephalum were given by Kostopoulos (2009), Rios et al. (2016), and Solounias and Danowitz (2016a).

Due to the scarcity of the fossil material, there is no obvious sexual dimorphism detected within Helladotherium from Kavakdere. However, metrical comparison with specimens from other fossiliferous sites reveal the relative size of the large sivathere from Kavakdere. Following Roussiakis and Iliopoulos (2004), we compared ratios between the proximal and distal epiphyses of all post-cranial long bones (radius, metacarpus, tibia and metatarsus), from various fossiliferous localities, where the size variation is more prominent (Fig. 3). In all cases, the Kavakdere specimens plot very close to the morphospaces of Samotherium major, suggesting a relatively small size of H. duvernoyi.

Genus Bramatherium Falconer, 1845

Bramatherium perimense (Falconer, 1845)

Material: PV-150, left metatarsal; PV-153, left metatarsal; PV-236, proximal phalanx (Fig. 4; Table 2).

Descriptions: The fossil material of B. perimense is limited to two metatarsals, as well as a proximal phalanx. The metatarsus (PV-150, PV-153; Fig. 4A-B) is very long and robust. Proximally, the surface for the naviculocuboideum is oval to kidney-shaped since the palmar rim of the surface bends notably towards the synovial fossa. The surface for the external cuneiform is long and slightly larger than the surface for the naviculocuboideum, with an almost rectangle semi-circular shape. The surface for the medial cuneiform is small, with the palmar rim being slightly bifurcated. Between these two surfaces, an additional small triangle-shaped articular surface can be noted. This surface is on the same level as the cuneiform surfaces and represents the remnant of the lateral fifth metatarsal. In plantar view, the epicondyles are all strong and well-separated. The dorsal head of the lateral epicondyle is rounded, bearing a small bony protuberance proximally. The ventral head of the lateral epicondyle is long and thin, leading to the lateral ridge of the central trough. The medial epicondyle is generally stronger and more robust. The ventral head is blunt but very strong, leading to the blunt medial ridge of the central trough. Between the medial and lateral epicondyles there is a weak but visible spindle-shaped pygmaios, which is slightly elevating above the surface of the basis. The central trough is somewhat shallow, and it flattens towards the distal shaft. On the distal epiphysis, the keels of the medial and the lateral condyles are strong and equally developed in plantar and dorsal aspect.

The proximal phalanx (PV-236; Fig. 4C) is very long and robust. The medial and lateral margins of the corpus are only slightly concave. On the articular fovea, a deep trough is separating the medial from the larger lateral articular facet. The palmar tubercles are long, covering approximately the upper 40% of the phalanx. The head is strongly asymmetrical and has almost the same width as the corpus.

Comparisons and remarks: Bramatherium, including the synonymous genera Hydaspitherium Lydekker (1876) and Vishnutherium Lydekker (1876), constitutes a widespread upper Miocene sivatherine. The taxon has been reported from numerous Asian localities in Thailand, Myanmar, India, Pakistan, United Arab Emirates and Turkey (Antoine et al., 2013, Bhatti et al., 2012, Bibi et al., 2013, Brunet et al., 1981, Colbert, 1935, Gaur et al., 1985, Gentry, 2003, Geraads and Güleç, 1999, Khan et al., 2014, Lewis, 1939, Lydekker, 1878, Matthew, 1929, Nishioka et al., 2014, Raza et al., 2002, Sehgal, 2015, Sehgal and Nanda, 2002a, Sehgal and Nanda, 2002b and Welcomme et al., 1997). However, the determination of the taxon has been almost solely based on cranial and dental characters, while post cranial elements are rarely described.

Bramatherium is no stranger to the fossiliferous horizons at Kavakdere, since it was the first taxon to be comprehensively described from the locality (Geraads and Güleç, 1999). The authors of this study also included a brief description of a humerus and a metatarsus. Later, new comparative studies focused on metatarsals and astragali, gave a better image and understanding of the osteology of the taxon (Rios et al., 2016; Solounias and Danowitz, 2016a), especially in comparison to H. duvernoyi, since the two taxa have been considered synonymous in the past (Matthew, 1929). Nevertheless, the osteological differences between most post cranial skeletal elements of the different Bramatherium species are still unclear.

The three species recognized are B. perimense, B. megacephalum Lydekker (1876), and B. grande Lydekker (1876), with the latter circumscription based solely on dental material. The post cranial long bones, and especially the metapodials of Helladotherium and Bramatherium exhibit a high metrical overlapping (Solounias, 2007; Fig. 5). Therefore, metrical comparison alone, cannot provide a conclusive taxonomic interpretation. Nevertheless, metatarsals of H. duvernoyi and B. megacephalum differ in many ways, with B. megacephalum having an additional distinct pygmaios, as well as a remainder of the lateral fifth metapodial, which are absent in H. duvernoyi (Rios et al., 2016).

The above-described metatarsals both exhibit the general sivatherine characters. However, both PV-150 and PV-153 have a small but distinct pygmaios as well as a remnant of the lateral fifth metatarsal. A metatarsal of Bramatherium sp. from Thailand (RIN 794; Nishioka et al., 2014: Fig. 4) demonstrates all the above-mentioned characters, but the pygmaios is notably more prominent than in the Kavakdere specimens, putting RIN 794 closer to B. megacephalum (AMNH 19688; Rios et al., 2016: Fig. 8). In addition, the irregularly shaped surface for the medial cuneiform in the Kavakdere metatarsalia, as opposed to the perfectly rounded surface of H. duvernoyi, fits closer to the almost heart-shaped medial cuneiform surface of B. megacephalum (Rios et al., 2016). This surface is not visible in the Thai (RIN 794) specimens due to the attachment of the naviculocuboideum at the basis of the metatarsal. Metrically, PV-150 comprises the longest Bramatherium metatarsal ever recorded. It appears approximately 10% longer and 14% and 20% wider in the anteroposterior diameters of the proximal and distal epiphysis, respectively, than in PV-153. This size difference could be attributed to sexual dimorphism, as noticed in long post cranial bones of Helladotherium duvernoyi and Bohlinia attica, Gaudry and Lartet (1856) (Roussiakis and Iliopoulos, 2004). Bramatherium shows a wide metatarsal length fluctuation (Fig. 6A). On a species level though, it becomes clear that B. perimense is generally larger than B. megacephalum (Fig. 6B), which can also be observed in dental measurements (Lewis, 1939).

First phalanges of Bramatherium are reported and illustrated by Colbert (1935) and they share the general sivatherine characters, such as a very long and thick corpus and strong palmar tubercles (Kostopoulos, 2009). The Kavakdere specimen also possesses these characters. However, the fact that PV-236 is much bigger than the rest of the recovered sivatherine phalanges, and it has a notably longer and more robust palmar tubercles than in H. duvernoyi, suggest that it belongs to the larger B. perimense instead of the smaller H. duvernoyi.

Subfamily Palaeotraginae Pilgrim, 1911

Genus Palaeotragus Gaudry, 1861

Palaeotragus rouenii (Gaudry, 1861)

Material: PV-176, right mandible with d3-m1; PV-244, left naviculocuboideum; PV-226, proximal phalanx (Fig. 7; Table 3).

Descriptions: Dental elements of P. rouenii from Kavakdere are only represented by a mandible bearing deciduous dentition (PV-176; Fig. 7A). The clade is short and thin, and the second deciduous premolar is broken. The d3 is long and strongly molarized. The anterior conid and anterior stylid are big and almost equally developed, with the latter being slightly stronger. The anterolabial cristid is large, projecting antero-labially, creating a small crescent surface, in occlusal aspect. The mesolingual and mesolabial conids are the largest cusps and they are well-separated by a transverse fossa. The mesolingual conid carries a strong fold, which is projecting postero-lingually, within the fossa. The posterolabial and posterolingual conids are isolated and separated from each other by a very thin and long fossa with a posterolingual direction. Both conids are strongly developed. Cingula and stylids are completely absent.

The d4 is long with very well-defined ectostylids. All lobes are simple, getting gradually larger posteriorly. The anterolabial conid is thin, with its apex being pointy labially. The anterior stylid is small and curved labially, being in contact with the base of the posterolabial conid of the d3. The anterolingual conid is simple and it extends posteriorly with a strong external-postmetacristid-like enamel projection, which surrounds the mesostylid completely. The metaconid and protoconid are both strong and simple and the metastylid is small and blunt. The entoconid is large, getting sturdier towards the base of the crown. The entostylid is small and isolated. The hypoconid is also large and the posterior apex of the post-hypocristid is bifurcated, surrounding the isolated entostylid.

The m1 carries a very strong anterior cingulum, forming a small stylid towards the protocone, as well as a tall and sharp ectostylid. In occlusal aspect, the overall morphology of the m1 is simple. The anterior lobe is slightly larger than the posterior lobe, due to the strong lingual projection of the metaconid. The anterior and posterior fossae are narrow and deep, while the labial conids exhibit no folds.

The naviculocuboideum (PV-244; Fig. 7B) has a sub-rectangle shape, proximally. The astragalar facets are parallel and almost equal in size. The calcaneal facet is very wide, long and it is not extending behind the lateral peak. In distal view, the facet for the metatarsal is small and semicircular. The facet for the external cuneiform is larger than the metatarsal facet, having a more rectangular shape. The facet for the medial cuneiform is small, triangular and well separated from the external cuneiform facet by a blunt crest.

The proximal phalanx (PV-226; Fig. 7C) is thin and long. The medial and lateral margins of the body are parallel to each other. The medial and lateral articular facets on the fovea are well separated by a deep and wide trough. In lateral aspect, the palmar tubercle is well-developed, but limited on the proximal part of the phalanx. The medial palmar tubercle is less developed than the lateral one, but it extends distally, stopping right above the distal trochlea.

Comparisons and remarks: Palaeotragus constitutes the most abundant late Miocene giraffid in the Greco-Iranian province (Gentry and Heizmann, 1996). The plethora or dental and post-cranial fossil elements brought to light, separated the Palaeotragus taxa into two distinct size groups: a small-sized group including P. rouenii and Palaeotragus microdon Koken (1885) and a large-sized group including Palaeotragus coelophrys Rodler and Weithofer (1890) and Palaeotragus quadricornis Bohlin (1926) (Geraads, 1986, Iliopoulos, 2003, Kostopoulos and Saraç, 2005, Kostopoulos et al., 1996 and Kostopoulos, 2009).

Palaeotragus rouenii comprises the most common palaeotragine species and was originally described from Pikermi, Greece (Gentry and Heizmann, 1996). However, despite the large number of findings, deciduous dentition of Palaeotragus is scarce, with only a few specimens mentioned from China, Ukraine, Moldova, Bulgaria, and Greece, and in most cases with pictures or illustrations lacking (Bakalov et al., 1962, Bohlin, 1926, Borissiak, 1914 and Godina, 1979). Metrical comparison of the lower deciduous dentition of P. coelophrys from China and Ukraine and P. rouenii from Moldova and Greece, reveals a large metrical variation on the length of d3 and d4 (Fig. 8). In both teeth, the large overlapping between the two taxa is significant. Even though the available data is limited, it is evident that the length of the deciduous premolars falls within the variation of P. coelophrys, while the length/width ratio of the d3 of PV-176 shows a closer resemblance to P. rouenii.

The lack of thorough descriptions and illustrations of deciduous lower dentition of Palaeotragus in previous studies, limits a morphological variation study. A mandible of Palaeotragus cf. coelophrys from China (Ex. 9; Bohlin, 1926: Plate II), as well as a mandible of P. rouenii from Samos (SMNS 13281e), share some common characters with PV-176. SMNS 13281e represents a part of left mandible with the d3, d4 and the proximal lobe of the m1 preserved. Although this specimen is notably more worn than P. rouenii from Kavakdere, SMNS 13281e demonstrates an almost identical morphology with PV-176. More specifically, on the d3, both specimens share a strong and crescent-shaped anterolabial cristid, the large and well-separated mesolingual and mesolabial conids and the well separated posterolabial and posterolingual conids. On the d4 of both individuals, the anterolingual conid exhibits a strong external-postmetacristid-like enamel protuberance, which is better pronounced in the Kavakdere specimen. Lastly, both specimens disclose an isolated entostylid. In contrast, the Chinese specimen (Ex. 9) demonstrates an isolated anterior conid and a much more developed anterior stylid and anterolabial cristid. Additionally, the posterolingual conid is strongly connected to the mesolingual conid.

Postcranial elements of late Miocene giraffids are commonly infrequent (Kostopoulos, 2009). Withal, naviculocuboideum specimens are also scarce. However, the metrics reveal that PV-244 belongs to a small palaeotragine. Measurements from previous studies show that Samotherium boissieri appears to be always larger than P. rouenii (Fig. 9). The transverse diameter (TD) of PV-244 is 71.52, slightly smaller than the mean value of the transverse diameter of S. boissieri from Samos (Kostopoulos, 2009). Conclusively, based on the above-listed descriptions and the further on comparisons, we assign the above-mentioned specimens to P. rouenii.

Genus Samotherium Forsyth-Major, 1888

Samotherium boissieri (Forsyth-Major, 1888)

Material: PV-242, right calcaneus; PV-243, right astragalus (Fig. 10; Table 4).

Descriptions: PV-242 represents a complete calcaneum (Fig. 10A). The sustentaculum tali is fairly developed and equally developed laterally and medially. The groove for the tendon of M. flexor digitorum lateralis is deep and well defined. The articular surface for the lateral malleolus is strong and robust. The articular surface for the cubonavicular is slightly concave, with parallel margins.

The astragalus (PV-243; Fig. 10B) is almost symmetrical in dorsal aspect. The lateral ridge of the trochlea is only slightly larger than the medial one. The trochlear groove is wide, and the central fossa is shallow. The head is also symmetrical, with the lateral trochlea being somewhat bigger than the medial trochlea. In ventral view, the proximal triangular fossa is deep, extending into an equally deep interarticular groove. The medial and lateral ridges of the ventral articular surface are parallel. There is a notable medial scala. The distal intracephalic fossa appears in two distinct areas, both positioned laterally, with the second one placed more distally.

Comparisons and remarks: Samotherium was first described by Forsyth-Major (1888) based on the remains of a large artiodactyle from Samos, but without a designated holotype. The two most common Samotherium species, which were widespread across the Pikermian biome, are S. boissieri and the larger S. major. Samotherium major is a descendant of S. boissieri and replaced the latter about 7.4 million years ago, at the transition between the MN11 and MN12 zones (Kostopoulos et al., 2003 and Kostopoulos, 2009). S. boissieri is reported from numerous localities in Greece, Turkey, and Iraq (Becker-Platen et al., 1975, Geraads, 1974, Köhler et al., 1995 and Kostopoulos, 2009 and literature within; Solounias and Danowitz, 2016b and Thomas et al., 1980). In Anatolia, S. boissieri was found at Gülpınar, Mahmutgazi, Kemiklitepe A/B, Akkaşdağı and Taşkinpaşa (Becker-Platen et al., 1975, Geraads, 1994, Karadenizli et al., 2005, Kostopoulos and Saraç, 2005, Saraç, 2003 and Şenyürek, 1954).

The overall structure of the two above-described specimens from Kavakdere agree with the morphology of a medium-sized palaeotragine (Kostopoulos, 2009 and Solounias and Danowitz, 2016a). Further metrical comparison of PV-242 and PV-243 with S. boissieri and S. major from various fossiliferous sites agrees with the morphological conclusion (Fig. 11). Specifically, the calcaneus from Kavakdere shows a small maximum height, plotting very close to the small S. boissieri individuals from Samos. The astragalus falls almost in the middle of the morphospaces of S. boissieri. With a lateral astragalar trochlear length (Llat) of 88.1 mm, in addition to the small maximum calcaneal length, it is concluded that S. boissieri is represented in Kavakdere by one female individual (Kostopoulos, 2009).

Genus Alcicephalus Rodler and Weithofer, 1890

Alcicephalus neumayri (Rodler and Weithofer, 1890)

Material: PV-245, right trapezoideo-capitatum; PV-235, right astragalus; PV-238, right naviculocuboideum (Fig. 12; Table 5).

Reference material: NHMW 2019/0018/0001, left astragalus; NHMW 2019/0018/0002, left astragalus; NHMW 2019/0018/0003, left astragalus; NHMW 2019/0018/0004, right astragalus (Table 6).

Descriptions: The trapezoideo-capitatum (PV-245; Fig. 12A) has a sub-quadrangular shape in cranial aspect, with the transverse diameter being slightly larger than the antero-posterior diameter (Table 5). The medial wall is straight, and the medial groove is shallow and wide. The articular surface for the scaphoid is deep and the lunatum surface is highly asymmetrical and shallow. The crests separating the two facets are strong but short and blunt.

There is only one astragalus of A. neumayri found (PV-235; Fig. 12B). In dorsal aspect, the lateral ridge of the trochlea is significantly taller and only slightly thicker than the medial ridge. However, both ridges are straight and parallel to each other. The central fossa is wide and shallow, extending laterally with a small grove towards the lateral collum tali. The lateral collum tali is flat, while the medial collum tali carries a pointy bulge. In ventral view, the interarticular groove is narrow, leading to a wider triangular fossa. The ventral articular surface is irregularly shaped, with the medial ridge carrying a weak medial scala, which is visible on the medial ridge but not there are no defined limits on the ventral articular surface. The lateral margin gets notably concave distally. The distal intracephalic fossa is present but faint and not well confined.

The naviculocuboideum (PV-238; Fig. 12C) has a rectangle shape in proximal view. The astragalar facets are almost equally developed, with the medial facet being slightly narrower that the lateral one. The medial peak is short but is very prominent and has a sharp apex. The lateral pick is more robust and higher. The calcaneal facet is wide, and it is not extending behind the lateral peak, common feature of samotherines. In distal aspect, the facet for the metatarsal is wide and semi-circular in shape. There is a wide opening on the distal part of that surface, which suggests a strong insertion of the tendons of the digital flexor muscles leading towards the proximal metatarsal canal. The facet for the external cuneiform is notably smaller than the latter surface and sub-rectangle. The medial cuneiform facet is triangular and almost completely isolated from the facet of the external cuneiform.

Comparisons and remarks: Alcicephalus neumayri has been reported from its type locality, Maragheh, as well as from North China and it is the most frequently occurring giraffid at the easternmost border of the Pikermian biome (De Mecquenem, 1924-1925, Gaziry, 1987, Rodler and Weithofer, 1890 and Solounias and Danowitz, 2016b). Due to the similarities between Alcicephalus and Samotherium, the two genera we considered synonymous for a long time (Hamilton, 1978 and Simpson, 1945). However, a recent study by Hou et al. (2014) pointed out the cranial differences between the two genera and re-established Alcicephalus as a valid genus. Even though A. neumayri is mostly known from dental and cranial material, recent data published by Solounias and Danowitz (2016b), as well as new analyses (for this study) on unpublished material from Maragheh (hosted in the collections of NHMW), allowed for a detailed comparison with the astragalus from Kavakdere.

Metrical comparison of the post-cranial elements clearly separates the carpal and tarsal bones of A. neumayri from those of S. major and H. duvernoyi (Fig. 13). The trapezoideo-capitatum (PV-245), astragalus (PV-235) and naviculocuboideum (PV-238) clearly belong to a species smaller than Helladotherium. Morphologically, the trapezoideo-capitatum has an almost rectangle shape and blunt cranial crests, characters that are not only different from those of H. duvernoyi but also typical for samotheriines (Kostopoulos, 2009). Additionally, the naviculocuboideum displays a short calcanear facet, which in uncommon in Sivatheriinae (Kostopoulos, 2009, Nishioka et al., 2014 and Solounias and Danowitz, 2016a). The medial astragalar facet is blunt, protruding only slightly, which is responsible for the faint intracephalic fossa of the astragalus. Lastly, the triangular facet for the medial cuneiform, as well as the fossa on the distal part of the facet for the metatarsal comprise unique characters on the naviculocuboideum of A. neumayri.

The astragalus constitutes a highly diagnostic skeletal element for Giraffidae. A recent study conducted by Solounias and Danowitz (2016a) described and listed all the different characters of the astragali of various giraffid taxa. In a late study, Solounias and Danowitz (2016b) showed the coexistence of Alcicephalus neumayri and Samotherium major at Maragheh, where the astragali are well described and the morphological differences between the two taxa were briefly indicated. Further investigation of the Maragheh collection hosted in NHMW, confirms the coexistence of two samotheriines at Maragheh. Additionally, a descent collection of astragali allowed to depict the morphological differences between the two taxa (Fig. 14).

In dorsal view, the astragalus of A. neumayri exhibits lateral edge which is notably taller but not much thicker that the medial ridge of the trochlea. In Helladotherium and S. major, the lateral ridge is much thicker than the medial one and, in the latter taxon, the two ridges do not exhibit such a height difference (Solounias and Danowitz, 2016a). Additionally, in A. neumayri there is a large and irregularly shaped central fossa, which indicatively expands laterally, between the lateral ridge of the trochlea and the lateral collum tali. The medial groove is very wide, bearing a robust medial bulge. The lateral collum tali is also quite broad without carrying a lateral notch. Respectively, in S. major the central fossa appears to be more rounded and placed centrally, at the base of the trochlear groove. The medial groove is also very open, with a much weaker medial bulge. The lateral collum tali is narrower than in A. neumayri, while bearing a well-developed lateral notch (Solounias and Danowitz, 2016a). In plantar aspect, the astragali of A. neumayri exhibit an irregularly-shaped ventral articular surface. On the distal and lateral side, there is a characteristic concavity of the articular surface, while the medial scala has vague limits or is hardly visible. The distal intracephalic fossa exhibits a double depression, common character for samotherines (Solounias and Danowitz, 2016a). However, the limits of the fossae are hard to define. Correspondingly, the astragali of S. major show a more regular, rectangular shape of the ventral articular surface. The medial scala, even though weak, is distinct with determinable limits, and a characteristic and conspicuous double-sectioned distal intracephalic fossa is also present (Solounias and Danowitz, 2016a).

Up to date, few studies have been conducted on fossil remains from the fossiliferous horizons at Kavakdere. Ozansoy (1965) was the first to study fossil remains from Kavakdere, recognizing Helladotherium sp. and Camelopardalis sp. as the only two giraffid taxa. Later, Becker-Platen et al. (1975) updated the faunal list for Kavakdere, adding Giraffa sp. to the previously identified giraffid taxa. However, in both studies, the basis for their determination is unknown, since comprehensive descriptions and figures of the fossil material are missing. A study by Köhler (1987), focusing on Miocene bovids from Turkey also presented material of Protoryx sp. Forsyth-Major (1891) from Kavakdere, adding yet another taxon to the unclear ruminant list from this locality. The first real taxonomic study on fossil Giraffidae from Kavakdere was conducted by Geraads and Güleç (1999). These authors described an almost complete skull of Bramatherium perimense, hosted in MTA. The material described herein clarifies the taxonomic position of giraffid material from Kavakdere. It verifies the presence of Bramatherium perimense and provides evidence for four additional giraffid taxa, H. duvernoyi, Palaeotragus rouenii, Samotherium boissieri, and Alcicephalus neumayri.

Kavakdere was initially placed between the middle Vallesian and early Turolian by Ozansoy (1965) and later, ambiguously assigned to the MN11 zone by Köhler (1987). Based on new findings, Geraads and Güleç (1999) assigned Kavakdere to middle Turolian. Succeeding, the palaeomagnetic dating established by Kappelman et al. (2003) placed all Kavakdere localities within MN11.

Palaeotragus rouenii has a chronostratigraphic distribution that ranges between late Vallesian (MN10) and late Turolian (MN 13) (Gentry et al., 1999, Kostopoulos, 2009 and Koufos et al., 2009). Helladotherium duvernoyi has also a wide distribution, which ranges from late Vallesian to late Turolian, with the first occurrence from the late Vallesian of Nikiti (Kostopoulos and Koufos, 2006, Kostopoulos et al., 1996, Kostopoulos, 2009 and Koufos et al., 2009). Bramatherium perimense is known from both the MN10 and MN11 of Pakistan and Turkey, as well as from the type locality of Perim (Piram) Island, India (Falconer, 1845, Geraads and Güleç, 1999 and Welcomme et al., 1997). However, the type horizon is unknown, and the exact age of the holotype is uncertain. Samotherium boissieri first appeared in the late Vallesian of Gülpınar and survived until the early middle Turolian (Marra et al., 2011). The taxon finds its peak of abundance in the MN11 where it appears as the dominant species of the famous locality Old Mills Beds, Samos, Greece (Bernor et al., 1996, Kostopoulos et al., 2003 and Koufos et al., 1997).

So far, Alcicephalus neumayri has only been reported from localities at Maragheh, Iran (Bernor, 1986 and Rodler and Weithofer, 1890), as well as China, and it is in fact the most abundant giraffid known from the eastern outskirts of the Pikermian biome (Solounias and Danowitz, 2016b). However, there is no exact indication regarding the stratigraphic origin of A. neumayri, giving the taxon a general chronostratigraphic range of lower to middle Turolian (MN11–MN12). The presence of A. neumayri in Kavakdere comprises the westernmost occurrence of this taxon and suggests a more dominant presence of Alcicephalus in the Pikermian biome than previously advocated.

Conclusively, most faunal remains of Giraffidae from Kavakdere agree with the chronostratigraphic conclusions of previous studies. In addition, the westernmost record of A. neumayri is reported. The new findings enrich the so-far limited fauna list of the fossiliferous site and new insights on the osteology of Bramatherium and Alcicephalus are documented.