Hoplitomeryx apruthiensis, Mazza & Rustioni, 2011

Mazza, Paul P. A. & Rustioni, Marco, 2011, Five new species of Hoplitomeryx from the Neogene of Abruzzo and Apulia (central and southern Italy) with revision of the genus and of Hoplitomeryx matthei Leinders, 1983, Zoological Journal of the Linnean Society 163 (4), pp. 1304-1333 : 1322-1324

HOPLITOMERYX APRUTHIENSIS SP. NOV.

( TABLE 1, FIGS 4 , 5 )

Holotype: Right hemimandible SCT 29.

Paratypes: Maxillaries SCT 59, SCT 125; mandibles SCT 16, SCT 50, SCT 51, SCT 58 + SCT 67, SCT 79, SCT 71, SCT 81, SCT 89, SCT 102, SCT 195, RGM 261.134, RGM 425.473, RGM 178.547.

Type locality and horizon: Holotype and paratypes tagged SCT from the Tortonian Scontrone Member of the Lithothamnium Limestone ( Patacca et al., 2008; 41°45′15.54″N, 14°2′13.14″E), outskirts of Scontrone , southern border of the National Park of Abruzzi, L’Aquila, central Italy . Paratype RGM 261.134 comes from the Messinian karstic fissure filling called Nazario 4 in the limestone quarry Nazario ; RGM 178.547 comes from the Messinian karstic fissure filling called Pizzicoli 1 in the limestone quarry Pizzicoli ; RGM 425.473 comes from the Messinian karstic fissure filling called Fina N in the limestone quarry Fina. The three quarries are located between Apricena and Poggio Imperiale, Foggia, Gargano promontory, south-eastern Italy (41°48′12″N, 15°23′04″E) .

Preservation and deposition of type specimens: Scontrone specimens: Soprintendenza Archeologica dell’Abruzzo ( Chieti , central Italy); Gargano specimens: Museum Naturalis, Leiden (the Netherlands) .

Etymology: From the Latin name of the region Abruzzo (central Italy).

Diagnosis: Apomorphies of species: mesodont cheek teeth ( HI = 1.02). Parastyle and mesostyle very robust and paracone supported by prominent median rib. Weak external rib of metacone and weak metastyle. Upper molars very similar to one another, with trapezoidal, closely packed lingual crescents. Protocone somewhat smaller than metacone. Tiny entostyle on second molars. Lingual walls somewhat more corrugated than labial walls in upper check teeth, opposite in lower ones. Mandible with slightly sinuous horizontal ramus; marked mandibular scissure; lower cheek dental formula: 2–3; premolars compressed mesiodistally and enlarged labiolingually; molars elongated mesiodistally and somewhat compressed labiolingually; paraconid absent or rudimentary; lingually open mesial fossette; metastylid and postentocristid strong; small ectostylid on each lower molar; third lower molars with wide, mesiolingually open mesial fossette; distal margin of hypoconulid separated from entoconulid occlusalward, and fused to it towards the collar; cementum occasionally present; cingula absent in lower cheek teeth.

Differential diagnosis: See Table 1.

Description of holotype: Lingual crescents of upper molars closely packed. Mandible tapers abruptly rostrally. Fairly long diastema in front of p2. Ventral profile markedly convex under the lateral dentition. Marked mandibular scissure. p3 and p4 short, somewhat compressed mesiodistally and enlarged labiolingually. Parastylid well developed, paraconid absent; weak, backward verging metaconid. Entoconid well developed and backward verging like metaconid. Entostylid very small. Vertical groove on the posterolingual region of p4. Labial enamel wall corrugated, lingual wall smooth. m1–m2 elongated mesiodistally and somewhat compressed labiolingually. Labial conids markedly triangular. m1 tightly in contact with p4, mesial wall flattened, preprotocristid bent abruptly in lingual direction with marked angle. Premetacristid very sharp and prominent lingually. Metastylid and postentocristid also very sharp and prominent. Preprotocristid fused to premetaconid crista, and postprotocristid to pre-entocristid. Hypoconid isolated. Small ectostylids. Labial enamel wall corrugated, lingual wall quite smoother. Residual cementum. m3 with tetraconid similar to that of m2. Premetacristid bent lingually, and preprotocristid separated from it, mesial fossette thus wide and opened mesiolingually. Distal margins of hypoconulid and entoconulid separated occlusalwards and rapidly fused towards collar.

Additional characters shown by paratypes: Hoplitomeryx apruthiensis is the most mesodont of the species described here. Lower premolar to molar ratio (p3-p4/m1-m3) in lower cheek toothrows of Scontrone specimens: 0.33–0.34; not assessable in the available Gargano specimens. Occlusal surfaces of lower cheek teeth quite inclined outwards; inner cuspids sharp and pointed for long, whereas outer cuspids affected by relatively higher degrees of wear.

M1–M2–M3. Molars very similar to one another. All bear robust parastyles, even stronger mesostyles, as well as considerably developed labial rib of the paracone. Much weaker external rib of metacone and metastyles. Lingual crescents trapezoidal, and postprotocristae and postmetaconule cristae robust. M3 with large metaconule. Cingula and cementum not present. Lingual crescents very closely spaced. Tiny entostyle in M2.

p3–p4. Paraconid absent, or rudimentary in poorly worn specimens, obliterating as wear progresses.

m1–m2. In unworn or moderately worn first lower molars, preprotocristid extended to contact premetaconid crista, and postprotocristid to contact preentocristid. As wear progresses, these structures normally fuse together, so that protoconid connects mesially with premetaconid crista, as well as distally with pre-entocristid. Hypoconid isolated from the other conids at most levels of wear; only in considerably worn specimens posthypocristid fused to postentocristid. Prehypocristid fused mesially to postprotoscristid only in heavily worn teeth. Small ectostylid. Labial enamel wall corrugated, lingual wall quite smoother. Residual cementum on some specimens.

Measurements: See Table 2.

Figures

Figure 4. A, Hoplitomeryx apruthiensis sp. nov., right maxillary (SCT 59): labial view. B, Hoplitomeryx apruthiensis sp. nov., right maxillary (SCT 59): lingual view. C, Hoplitomeryx apruthiensis sp. nov., right maxillary (SCT 59): occlusal view. D, Hoplitomeryx apruthiensis sp. nov., right mandible (SCT 29): labial view. E, Hoplitomeryx apruthiensis sp. nov., right mandible (SCT 29): lingual view. F, Hoplitomeryx apruthiensis sp. nov., right mandible (SCT 29): occlusal view. G, Hoplitomeryx magnus sp. nov., left maxillary (SCT 86): occlusal view. H, Hoplitomeryx magnus sp. nov., left maxillary (SCT 86): lingual view. I, Hoplitomeryx magnus sp. nov., left maxillary (SCT 86): labial view. J, Hoplitomeryx magnus sp. nov., left mandible (SCT 20): labial view. K, Hoplitomeryx magnus sp. nov., left mandible (SCT 20): lingual view. L, Hoplitomeryx magnus sp. nov., left mandible (SCT 20): occlusal view. M, Hoplitomeryx magnus sp. nov., left mandible (RGM 260.951): lingual view. N, Hoplitomeryx magnus sp. nov., left mandible (RGM 260.951): labial view. O, Hoplitomeryx magnus sp. nov., left mandible (RGM 260.951): occlusal view.

Figure 5. Hoplitomeryx minutus sp. nov., left p3: occlusal view. B, Hoplitomeryx minutus sp. nov., left p4: occlusal view. C, Hoplitomeryx minutus sp. nov., left m3: occlusal view. D, Hoplitomeryx falcidens sp. nov., left p3: occlusal view. E, Hoplitomeryx falcidens sp. nov., left p4: occlusal view. F, Hoplitomeryx falcidens sp. nov., left m3: occlusal view. G, Hoplitomeryx apulicus sp. nov., right p3: occlusal view. H, Hoplitomeryx apulicus sp. nov., right p4: occlusal view. I, Hoplitomeryx apulicus sp. nov., right m3: occlusal view. J, Hoplitomeryx matthei sp. nov., left p3: occlusal view. K, Hoplitomeryx matthei sp. nov., left p4: occlusal view. L, Hoplitomeryx matthei sp. nov., left m3: occlusal view. M, Hoplitomeryx apruthiensis sp. nov., right p3: occlusal view. N, Hoplitomeryx apruthiensis sp. nov., right p4: occlusal view. O, Hoplitomeryx apruthiensis sp. nov., right m3: occlusal view. P, Hoplitomeryx magnus sp. nov., left p3: occlusal view. Q, Hoplitomeryx magnus sp. nov., left p4: occlusal view. R, Hoplitomeryx magnus sp. nov., left m3: occlusal view.