Hoplitomeryx minutus Mazza & Rustioni 2011, SP. NOV.
Creators: name: Mazza, Paul P. A.
name: Rustioni, Marco
Publisher: name: Zenodo
Year: 2011
Subjects: Biodiversity
Taxonomy
Animalia
Chordata
Mammalia
Artiodactyla
Hoplitomerycidae
Hoplitomeryx
Hoplitomeryx minutus

description: HOPLITOMERYX MINUTUS SP. NOV.  (TABLE 1, FIGS 1, 5)   Holotype: Right hemimandible SCT 77.   
 Paratypes: Mandibles SCT 60, SCT 73, SCT 78, SCT 155, RGM 261.147, RGM 261.136.   
 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 261.147 from the Messinian karstic fissure filling called Chiro 29 in the limestone quarry Chiro, and paratype RGM 261.136 from the Messinian karstic fissure filling called Nazario 4 in the limestone quarry Nazario. Both quarries 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: The name refers to the small dimensions of the species.   
 Diagnosis: Apomorphies of species: mandible with horizontal ramus slender and sinuous, and with uniformly convex ventral profile; lower cheek dental formula: 3– 3 in the Scontrone specimens, 2–3 in the Gargano specimens; brachyodont lateral dentition (HI = 0.67); lower premolars very small with no paraconid, robust and salient metaconid and strong entoconid; lower molars with widely spaced, triangular labial conids, flattened mesial enamel walls, isolated hypoconid, even in heavily worn teeth, strong metastylids, postentocristids, and ectostylids; distal margin of hypoconulid separated from entoconulid towards the occlusal edge of the crown and fused with it towards the collar; lingual enamel wall smooth, labial enamel wall moderately corrugated; molars with cingulum on the mesiolabial base of protoconids.   
 Differential diagnosis: See Table 1.   
 Description of holotype: Fragment of horizontal ramus, fairly low and slender, with sharp ventral border. Mandibular scissure barely marked. The specimen preserves the three lower molars. Labial conids markedly triangular, inclined outwards and backwards and fairly widely separated from one another. Mesial walls flat. Preprotocristid abruptly bent lingually forming a marked angle. Mesial fossette opened lingually. Postprotocristid never fused to other structures keeping free all the way down to base of crown. Hypoconid isolated from other conids. Robust wear-resistant lingual ribs and stylids, which give teeth high occlusal relieves. Ectostylids in all molars. Well-developed mesiolabial cingula at the base of protoconids. In m3 distal margin of hypoconulid occlusally separated from entoconulid, rapidly fused to it towards base of tooth. Labial enamel moderately corrugated, lingual enamel smooth.   
Additional characters shown by paratypes: Horizontal ramus tapers gradually rostrally. Lower premolar to molar ratio: p2-p4/m1-m3: 0.50; p3-p4/ m1-m3: 0.38 in the Scontrone specimens; not assessable in the available Gargano specimens. Very thin film of cementum-like veneer occasionally present in labial valleys of lower molars.  
p2. Tooth stout, somewhat compressed mesiodistally and enlarged labiolingually. Parastylid well developed, paraconid absent. Metaconid the highest cuspid, it protrudes considerably lingually. Entoconid well developed, entostylid absent. Lingual enamel wall smooth.  
p3–p4. Morphologically similar to p2, but larger and proportionally more elongated mesiodistally. Parastylid well developed, paraconid rudimentary and  
 Hoplitomeryx   
 (genus characters) H. minutus H. falcidens H. apulicus H. matthei H. apruthiensis H. magnus   
Check teeth brachyodont Brachyodont lateral Mesodont Brachyodont lateral Mesodont Mesodont or mesodont dentition dentition  
Lower cheek dental Lower cheek dental Lower cheek dental Lower dental formula: in Lower cheek dental formula: 3– 3 in the formula: 3– 3 in the formula: 3– 3 in the Gargano specimens: formula: 2–3 Scontrone specimens, Scontrone specimens, Scontrone specimens, 2–3, unknown in  
2–3 in the Gargano 2–3 in the Gargano 2–3 in the Gargano Scontrone specimens specimens specimens representatives at the moment  
Variously developed parastyle and mesostyle in upper cheek teeth  
Sabre-like upper canines Strong, slender, and can Sometimes be sharp upper Canines present Premolars compressed mesiodistally and enlarged labiolingually Upper molars often Molars elongated wider than they are mesiodistally and long somewhat compressed labiolingually  
P3 with centrally situated and lingually directed protocone  
P4 and M3 with large metaconule Upper molars with Upper molars very triangular protocone similar to one another, and trapezoidal with trapezoidal, metaconule closely packed lingual crescents  
Lingual cusps very tightly spaced in M1,  
somewhat more separated in M2 and  
M3  
Protocone somewhat smaller than metacone Metacone sometimes Weak external rib of with small pillars on metacone labial face of upper molars  
Labial wall of metacone almost flat  
Strong external paracone Paracone supported by rib prominent median rib Mesodont  
Lower cheek dental formula: unknown at the moment in the Scontrone representatives, 2–3 in Gargano specimens  
Presence of upper canines  
External rib of metacone absent  
Paracone supported by robust and prominent median rib  
 Hoplitomeryx   
 (genus characters) H. minutus H. falcidens H. apulicus H. matthei H. apruthiensis H. magnus   
Incipient entostyle Entostyle (in upper No entostyles (in upper Tiny entostyle on second occasionally from teeth absent) teeth) molars mesial wall of metaconule of first and second upper molars  
Cingula absent in upper Thin cementum cover cheek teeth  
Lower molars with In lower molars labial Labial conids closely widely spaced labial cuspids widely spaced conids, spaced and somewhat backward-verging  
Lower molars with In lower molars labial Labial conids triangular labial cuspids triangular markedly triangular conids,  
Flattened mesial Flattened mesial walls enamel walls  
Check teeth with globose cuspids and stylids not prominent lower molars with swollen lingual enamel walls and with cuspids that remain isolated even in worn teeth  
Check teeth with occlusal surfaces markedly inclined outwards because of strong differential wear between inner and outer cuspids  
M1 with very reduced entostyle  
Cementum absent and overall smooth enamel in upper cheek teeth  
Lower molars with lingual cuspids relatively less worn than labial cuspids  
Lower molars with widely spaced, triangular, backward-verging labial cuspids  
Flattened mesial enamel walls  
In worn molars protoconid connected mesially with metaconid and distally with entoconid, and hypoconid connected with postprotocristid and postentocristid  
p4 nonmolarized Elongated Mesiodistally Elongated Compressed Compressed compressed trigonid and small talonid  
Lingually open mesial fossette Small paraconid Lower premolars very Paraconid absent or Paraconid sometimes Paraconid present in Paraconid absent or occasionally present small with no present only in present in unworn unworn or poorly worn rudimentary paraconid, robust unworn lower lower premolars lower premolars and salient premolars entoconid well metaconid, and developed in lower strong entoconid premolars  
In p2 protoconid and metaconid of same height  
In p3 protoconid larger than metaconid,  
opposite in p4  
Isolated hypoconid Hypoconid well developed in lower premolars  
Parastylid well developed in lower premolars  
Metastylid generally Strong metastylids Metastylids well Metastylids well Poorly developed stylids Metastylid strong well developed in developed and developed but not lower molars protruding lingually protruding lingually  
Ectostylid occasionally Strong ectostylids Ectostylid low and Ectostylid very small Ectostylid small in m1, Small extostylid on each present, sometimes robust in m1, low in m1, absent in absent in m2 and m3 lower molar quite developed, on and blunt in other other molars lower molars molars  
Complete postentocristid Strong postentocristids Postentocristids well Postentocristids well Postentocristids not Postentocristid strong in lower molars developed and developed but not protruding lingually protruding lingually protruding lingually  
(in m3  
postentocristid hardly developed)  
Infrequent mesiolabial Molars with cingulum Weak cingulum at the Cingulum absent (in Cingula absent (in lower Cingula absent in lower cingulum on the mesiolabial base of the lower teeth) teeth) cheek teeth base of protoconids protoconid in m1  
and m2  
Third lower molars with wide, mesiolingually open mesial fossette Elongated  
In p3 and p4 paraconid barely developed or totally absent  
Protoconid and metaconid of same height protoconid isolated in unworn molars  
Hypoconid isolated in unworn molars  
Metastylid prominent, but blunt  
Ectostylids blunt and robust  
Postentocristid prominent, but blunt  
Protoconids with faint traces of cingulum at their base present only in barely worn teeth, otherwise totally absent; metaconid robust, very salient, exceeding in height the cupsids of all lower premolars, and in contact with protoconid. Entoconid well developed and protruding lingually. Entostylid also well developed. Lingual enamel wall smooth.  
m1. Tooth tightly in contact with fourth premolar. External rib of metaconid and entoconid strong, metastylid and postentocristid also quite robust. Robust ectostylid. Mesiolabial cingulum variously developed and at times supporting tiny cuspule.  
m2. Labial cuspids widely separated from one another with low, blunt ectostylid in between.  
m3. Low, pillar-like enamel structure sometimes present where distal margins of hypo- and entoconulid meet.  
 Measurements: See Table 2.
description: Published as part of 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, pp. 1304-1333 in Zoological Journal of the Linnean Society 163 (4) on pages 1306-1312, DOI: 10.1111/j.1096-3642.2011.00737.x, http://zenodo.org/record/5442183