Iberomeryx sp.

Métais, Grégoire, Coster, Pauline, Licht, Alexis, Ocakoğlu, Faruk & Beard, K. Christopher, 2023, Additions to the late Eocene Süngülü mammal fauna in Easternmost Anatolia and the Eocene-Oligocene transition at the periphery of Balkanatolia, Comptes Rendus Palevol 22 (35), pp. 711-727 : 714-716

Iberomeryx sp.

( Fig. 2 P-Q)

REFERRED MATERIAL. — Sü-2016 , left m3 (third lobe, hypoconulid lacking)

LOCALITY. — Outcrop of unnamed rock unit consisting of c. 40 cm thick tuffite bed containing gastropod operculae superposed by c. 30 cm thick white silty limestone with silicified nodules exposed in a streambed roughly two km northwest of Süngülü, Ardahan Province, Turkey (de Bruijn et al. 2003: fig. 1). Latest Eocene according to de Bruijn et al. (2018, 2019).

DESCRIPTION

The m3 is incomplete since the third lobe bearing the hypoconulid is damaged, and the mesial margin and labial flank of the protoconid are broken ( Fig. 2). The molar is brachyodont, and the protoconid is slightly taller than the metaconid, which is more mesially positioned than the protoconid. The premetacristid is absent. There is a strong wear facet on the preprotocristid and the mesial part of the molar is broken, hampering evaluation of the extension of this crest mesially and lingually; it is worth noting that the metaconid is not conical but instead shows an incipient labial crest, unlike the condition typically observed on m3 of Iberomeryx . The short internal posprotocristid is lingually oriented and joins the short and posterolabially oriented internal postmetacristid, but they do not reach the mesially oriented and elongated preentocristid that stops at the base of the posterior wall of the trigonid. The external postprotocristid is barely visible (but present) and fused with the distal portion of the prehypocristid. The metaconid displays a short and marked external postmetacristid. Although attenuated (on its labial side), the M-structure is present ( Fig. 2). The entoconid is more mesially positioned than the hypoconid, it displays a strong wear facet on its posterior face, and it is not transversely compressed as in Iberomeryx parvus . The posthypocristid extends lingually and its distal extremity is connected to a mesio-distally extended pre-hypoconulid cristid. There is a crest extending mesio-distally at the base of the posterior wall of the entoconid which is most probably a remnant of the internal pre-hypoconulid cristid, suggesting that the hypoconulid was connected to the rest of the talonid by two cristids.

TAXONOMIC ATTRIBUTION

Even considering intraspecific size variability, this m3 is roughly twice as large as would be expected for an m3 that would match the size of Sü-2009 (m1). The current sample from Süngülü does not allow us to estimate the size variability of Iberomeryx sp. cf. I. parvus , but the size of this m3 surpasses the size variability observable in the extant tragulid Tragulus kanchil (Raffles, 1821) , for example ( Meijaard & Groves 2004). Moreover, the morphology of this m3 is more bunodont and bulkier than the m1 of Iberomeryx sp. cf. I. parvus described below. The combination of an external postprotocristid, an internal postprotocristid, an internal postmetacristid and an external postmetacristid corresponds to the tragulid M-structure or Σ- structure, justifying identification of this molar as that of a tragulid ( Mottl 1961; Rössner 2007). However, given the paucity of the present material and pending additional data, we prefer to assign this tooth to Iberomeryx sp.