Scontromeryx mazzai, Van Der Geer, Alexandra A. E., 2014

Van Der Geer, Alexandra A. E., 2014, Systematic revision of the family Hoplitomerycidae Leinders, 1984 (Artiodactyla: Cervoidea), with the description of a new genus and four new species, Zootaxa 3847 (1), pp. 1-32 : 18

Scontromeryx mazzai sp. nov.

Fig. 6 H in Mazza & Rustioni (2011)

Hoplitomeryx sp. Leinders, 1984 – Rustioni et al. 1992: fig. 3 [uncatalogued skull fragment]; Mazza & Rustioni 1996: fig. 1 [SCT17, redrawn after Rustioni et al., 1992: fig. 1].

Taxon C—Mazza & Rustioni 1999 (partim): p. 307 [STC 72, STC 83].

Hoplitomeryx Leinders, 1984 — Mazza & Rustioni 1999 (partim): p. 305 [SCT80].

Hoplitomeryx matthei Leinders, 1984 — Mazza & Rustioni 2011 (partim): p. 1320, 1321, 1330, fig. 6, tables 1, 2 [SCT17, SCT72, SC T 80, SCT83].

Holotype. Skull fragment SCT17.

Paratypes. Mandible fragments SC T 80, SCT83, SCT72.

Diagnosis. A hoplitomerycid with two pairs of orbital horns. Mandible markedly pachyostotic with brachyodont dentition. The lower m2 and m3 lack ectostylids, a cingulum and cementum and have rugose enamel.

Differential diagnosis. Differs from S. minutus , S. falcidens and S. apulicus by pachyostosis of mandibular ramus and presence of orbital horns, differs from S. falcidens and S. apulicus by rugose enamel on its molars, differs from S. falcidens by absence of ectostylid in m2 and m3 and by having brachyodont teeth. Differs from S. minutus by absence of a cingulum and by rugose lingual enamel wall.

Derivation of name. Named in honour of Paul Mazza for his research on the artiodactyls from Scontrone.

Preservation and deposition. Soprintendenza Archeologica dell’Abruzzo (Chieti, central Italy).

Type locality and horizon. Tortonian Scontrone Member of the Lithothamnium Limestone ( Patacca et al., 2008; 41°45'15.54''N, 14°02' 13.14''E), outskirts of Scontrone, southern border of the National Park of Abruzzi, L’Aquila, central Italy.

Description. See Mazza & Rustioni (2011). Additional characters shown by paratypes revised after Mazza & Rustioni (1999). The paratypes SCT80 (m3), SCT83 (incomplete m2, badly preserved m3) and SCT72 (incomplete m2, m3, alveoles p2–m1) are fragmentary mandibles. The description here is after Mazza & Rustioni (1999) for SCT72 and SCT83. Horizontal ramus with marked pachyostosis. m2-m3. Brachyodont without ectostylids. The ribs and the styles are slightly prominent on the lingual enamel walls. The rear wings of the protoconids are fused to the anterior wings of the entoconids. The labial crescents are obliquely arranged backwards and have a V-shaped outline in occlusal view. The posterior lobe is bicuspid with the labial lobe exceeding the lingual lobe in size. No cingula, no cementum. The enamel is rugose.

Measurements. See Table 2 .

Remarks. Mazza & Rustioni (2011) attributed skull fragment SCT17 and three mandible fragments (SCT80, SCT83, SCT72) from Scontrone to Hoplitomeryx matthei . However, these specimens cannot be attributed to this species. According to Mazza & Rustioni (2011) there is no evidence of the possible presence of the nasal horn core in skull fragment SCT17, yet a nasal horn core is diagnostic for Hoplitomeryx matthei ( Leinders 1984) . Furthermore, the orbital horn cores of SCT17 show a combination of characters of Leinders’ (1984) horn core types I and II and constitutes thus a new horn core type, unlike any of Leinders’ (1984) types. As far as the mandibles are concerned, there is no evidence for the loss of the second premolar. This means that the presence of Hoplitomeryx matthei cannot be confirmed among the material from Scontrone. In order to avoid confusion, the four Scontrone specimens which are excluded here from the H. matthei material are attributed here to a new species as they cannot be attributed to any of the other Scontrone species defined by Mazza and Rustioni (2011).

Figures

FIGURE 6. Postcranial elements of Hoplitomeryx. A, left tibia (RGM 335.882 + 425.328; San Giovannino): medial view; B, right tibia (RGM 425.144; Chiro D 1): anterior view. Astragals of different size in anterior (dorsal) view: C, left astragal (RGM 425.385; Falcone 2 B); D, left astragal (RGM 260.863; San Giovannino); E, right astragal (RGM 425.421; Fina N). F, left astragal (RGM 263.951; Gargano, unknown fissure): lateral view; G, left calcaneum (RGM 260.901; San Giovannino): anterior view; H, same specimen: posterior view; I, same specimen: medial view; J,; K, detail of distal right metatarsal (RGM 178.518; San Giovannino) showing the proximal extension of the dorsal gully into the (fused) cubonavicular.