Nguruwe, Pickford, 1986

Orliac, Maëva J., Karadenizli, Levent, Antoine, Pierre-Olivier & Sen, Sevket, 2015, Small hyotheriine suids (Mammalia, Artiodactyla) from the late early Miocene of Turkey and a short overview of early Miocene small suoids in the Old World, Palaeontologia Electronica 16 (1), pp. 1-18 : 4-8

Nguruwe ? galaticum sp. nov.

Figures 2.1-3, 2.6 -14, 3, 4.1

zoobank.org/ F5EE51A1-3F6F-4E7A-BD88-E92349C813FB

Type specimen. SMT-1, fragmentary cranium preserving portions of the palate, of right and left zygomatic arches, and some fragments of the nasal or lachrymal bone; in situ left M1-M3 (M1 and M3 partly broken) and right P3, associated left P3 and right C isolated.

Type locality. Şemsettin , Çankiri-Çorum Basin , Turkey. Kumartaş Formation, late early Miocene .

Derivatio nominis. Neutral epithet named after « Galatia », name of the area of Çankiri-Çorum Basin at the Greek epoch.

Diagnosis. Hyotheriinae smaller than the species referred to Hyotherium ( H. meisneri , H. major , H. soemmeringi , H. youngi , and H. lacaillei ), with no prezygomatic shelf, similar in size to Aureliachoerus aurelianensis and Nguruwe kijivium as regarding the antero-posterior length of comparable cheek teeth; differs from A. aurelianensis in having a P3 with no accessory cusp in the postparacrista, and with a wider and shallower lingual basin bordered by a smaller lingual cingulum. Differs from available material of N. kijivium in displaying a smoother enamel surface and a paraconule not fused to the anterior cingulum on M2. Differs from

ORLIAC ET AL.: TURKISH EARLY MIOCENE SUIDS

Chicochoerus minus and Nguruwe namibense in its larger size.

Description of the Fragmentary Cranium

The specimen SMT-1 consists of a fragmentary cranium. On the left side, the palate with P3- M3 are preserved: (1) On the left side, the palate with P3-M3, and (2) on the right side, a short portion of the palate with P3 (only tooth preserved on this side), the root of the right jugal part of the zygomatic arch, the jugal portion of the left zygomatic arch, and some fragments of the nasal or lachrymal bone. The left side bears the roots of P4, fragmentary M1-2, and an almost completely broken M3 (only the labial wall of the paracone is preserved); the left P3 is set in a small isolated fragment of maxilla. The right canine is also preserved but is no longer in situ. Dental remains are only slightly worn and most of the groove-and-crest pattern is visible. Based on the available remains, the teeth of the fragmentary cranium SMT-1 can be used for taxonomy; what is left of the zygomatic arches, nasal and lachrymal bones are too damaged and deformed to be described. Only the root of the right zygomatic arch warrants description. The ventral surface of the anteriormost end of the zygomatic arch shows the imprints of the m. depressor rostri (and maybe m. dilatator naris lateralis) on a small concave surface reaching anteriorly the level of P3. This area is overhung by the straight ventral border of the anterior portion of the zygomatic arch. There is no trace of prezygomatic shelf ( Figure 2.3 ).

The right upper canine has most of its crown: only the apex is broken away. It is short, straight, and lingually inflated. Its root has a sulcus on the labial surface, most probably as a relic of the formerly separate roots. The morphology of the canine root suggests that the growth might have been prolonged, but was not continuous like the ever-growing canines of modern suids. The crown/ enamel surface bears an antero-lingual enamel ridge and a posterior one. The lingual side of both ridges is particularly sharp; the enamel is thin on the lingual surface, between the two ridges, compared to that observed on the labial surface of the crown. The anterior ridge is lined by a groove on its ventral surface. The crown has three distinct weakly developed enamel bands: anterior, posterior, and lingual ( Figure 2.6 -9), the ventral being the larger one. There is a little wear facet on the anterior surface of the crown.

The P3s are preserved on both sides of the specimen. The posterior part of the alveolus of P2 is just anterior to the roots of the P3, without a diastema. P3 bears only one cusp, the paracone, from which run two sharp cristae: the preparacrista connects the anterior cingulum at the anterolingual corner of the tooth, and the postparacrista joins the posterior cingulum at the posterolabial corner of the tooth. The tooth is almost unworn and the postparacrista is finely crenulated, with a small style where it connects to the posterior cingulum. The posterior part of the tooth comprises a wide lingual basin; it is anteriorly bordered by a small accessory cusp, merged with the lingual cingulum. The lingual basin is shallow and in continuity with the slope of the lingual flank of the paracone, its surface bears very small enamel knobs. The cingulum is small and continuous all around P3, with only a slight interruption on the labial surface of the paracone. P3 has two roots: a small anterior one and a wide posterior pillar.

The crown of P4 is totally broken and only its outline and roots can be observed. Three roots are identifiable (two labial and a lingual one).

M1 is badly damaged but the lingual half of the protocone and metacone are preserved, together with the metaconule and parts of the postmetacrista and of the centroconule; the paracone is missing. M2 is the most complete upper molar (the metaconule is missing). By contrast, only half of the paracone of M3 is preserved, while the rest of the crown is broken away. However, the outer profile of the tooth indicates clearly the presence of a posterior lobe. CT scan investigation of the specimen reveals that the lingual and labial roots of the molars are not fused ( Figure 3 ). The upper molars are strongly bunodont. On M2, the paracone bears a very light precrista, a long endocrista that joins the endoprotocrista, and a sharp postparacrista. These crests are underlined by grooves: namely the endoparafossa and preparafossa. A paraconule is present, partly fused to the anterior cingulum and separate from the preprotocrista by a groove. The protocone also bears an endoprotocrista but no postprotocrista. There is no clear endoprotofossa; the preprotofossa is short but deep, the preprotocrista is lined lingually by an ectoprotofossa. The centroconule is large on M2. The metacone is preserved on M1-2. It bears two clear cristae: ecto- and premetacrista. The ectometafossa is deep and faces the postparafossa. The presence of the endometacrista is difficult to ascertain; it might be on the edge of the wear facet located on the posterior surface of the metaconid; no trace of a postmetacrista is visible. The metaconule is only partly preserved on M1. The ecto-, pre-, and post-metacristules are visible. The ectometacristule is sharp, lined labially by a deep ectometafossule; it connects a very short lingual cingulum, located at the transverse valley.

The anterior cingulum is thick in all three upper molars; it is continuous with the labial cingulum that extends for the labial side of the tooth on M2, and most probably on M1, judging from its extension on the metacone. The posterior cingulum is strong on M1-2. Anteriorly, on M2, the mesiostyle and parastyle are small but identifiable and an ectostyle is present labially at the base of the paracone. A metastyle occurs on M1-M2 at the postero-labial corner. The enamel surface of the upper cheek teeth is slightly rugose.

Figures

FIGURE 2. Figure 2 Suid remains from Şemsettin, Çankiri-Çorum Basin, north Central Anatolia. Nguruwe? galaticum sp. nov.:1-3, fragmentary cranium, type specimen SMT-1 in 1) occlusal, 2) left lateral, 3) right lateral views; 6-9, right canine associated to SMT-1 in 6) ventral, 7) posterior, 8) lateral, 9) anterior view; 10-14, left P3 associated to SMT-1 in 10) occlusal, 11) labial, 12) anterior, 13) lingual, 14) posterior views. Hyotheriinae gen. et sp. indet: 4-5, isolated right dp4 SMT-2 in 4) occlusal, 5) labial views. Arrows indicate anterior direction for jugal teeth. Scale bars equal 5 mm.

FIGURE 3. 3D reconstruction of SMT-1 from Şemsettin in occlusal view and 1-2) CT scan slide showing root structure at different sections of the specimen: 1) buccal; 2) lingual. Arrows indicate anterior direction. Scale bar equals 10 mm.