Pannonictis nestii ( Martelli, 1906 )

Colombero, Simone, Pavia, Marco & Rook, Lorenzo, 2012, Pannonictis nestii (Galictinae, Mustelidae), a new element in the vertebrate association of the human site of Pirro Nord (Italy, Early Pleistocene), Geodiversitas 34 (3), pp. 665-681 : 672-674

Pannonictis nestii ( Martelli, 1906) ( Figs 3 ; 4 )

Proputorius nestii Martelli, 1906: 598 .

Pannonictis nestii – Ficcarelli & Torre 1967: 141. — Rook 1995: 856.

Pannonictis cf. nestii – García & Howell 2008: 9.

HOLOTYPE. — Left hemimandible bearing P 3 -M 2, from Upper Valdarno (Tuscany, Italy), housed in the Museo di Geologia e Paleontologia of the University of Florence and labeled as IGF 916.

MATERIAL EXAMINED. — Adult left hemimandible, almost complete ( PU 120257); uncomplete juvenile right hemimandible ( PU 126946); left lower canine ( PU 118847); right lower canine ( PU 118848); right upper canine ( PU 118846); left P4 ( PU 120242); left humerus ( PU 129095).

DESCRIPTION

Adult left hemimandible

The specimen ( Fig.3C, D ) is not complete in all of its parts. It lacks the coronoid process and, in the anterior part, it completely lacks the symphysis and the alveoli of the incisors are entirely absent. M 1 and P 4 are the only teeth present. The horizontal branch presents a fracture, which reaches the P 4 damaging the protoconid and moderately rotating the anterior part of the mandible.

The hemimandible appears stout and low. The ascending ramus is relatively wide. The angular process is somewhat thick especially in the lower part. It curves towards the medial side which presents a deep concavity. The mandibular condyle is low, slightly tilted to the dental side. No incisor is present. The canine alveolus is not complete but it suggests the presence of a large and deep root. The inferior mandibular margin descends slightly until it meets an inflection point just beneath the M 1 talonid, where it rises again gently. The masseteric fossa is very deep and extends further on the M 2 alveolus, almost reaching the M 1.

Although P 2 and P 3 are not present, we can observe the alveoli of these teeth occupied by the remains of their roots. They do not lie on the same line, but are slightly clockwise rotated. Thus, the posterior root of P 2 is almost at the same level of the anterior root of P 3, suggesting a partial over- lapping of these two teeth. As we have said, P 4 is partially damaged in such a way that the anterior part of the tooth is shifted ahead, not permitting the measurement of the dental element. It has a well-pronounced protoconid, as well as a relatively well-pronounced projection of the posterior basal area where a tiny cusplet rises from enamel swells. The M 1 is very worn, with low cusps. The M 1 protoconid is stout and well developed. The paraconid is well developed too, but it shows a higher degree of wear. The metaconid is not in line with the protoconid but slightly posterior. The talonid is worn and we cannot see other accessory cusps except for a very light sign of the hypoconid. The talonid appears as a concavity with the lingual side being more consumed so that it seems to be inclined towards that part.

Juvenile right hemimandible

The specimen is not complete. It lacks completely the coronoid process. The anterior part is broken at the level of the distal part of the alveolus of the inferior canine. The hemimandible has a lighter structure compared to the adult specimen. The ascending ramus is less large than it appears in the adult form. The angular process is barely developed. The mandibular condylus is not present and we can observe only a partially preserved tiny swelling of the bone. The masseteric fossa is deep, but shorter and more shallow than in the fully developed specimen. The inferior mandibular margin is slightly bended but we cannot observe a clear inflection point. The alveolar ridge is preserved from the posterior part of the canine alveolus. Even if the canine alveolus is partially preserved, it appears large and deeply set in the mandibular body. Slightly distally, a tiny alveolus is present on the buccal side. More lingually, we can notice the erupting P 3. Posteriorly two alveoli are present. Subsequently an M 1 in eruption is observable. The alveolar ridge ends with the M 2 alveolus. The M 1 paraconid is well developed even if lower than the protoconid. The metaconid is not in line with the protoconid but slightly posterior. The talonid is deep and we can observe well developed both the hypoconid and the hypoconulid. On the lingual side a tiny cusp is present developing from a low margin that encloses the basin of the molar. The talonid is inclined towards the lingual side.

By comparison with the adult specimen(PU120257) we can see that the alveolar ridge has comparable size while the posterior part is much shorter, being the whole structure less stout. This condition is also observable in the minor highness of the mandibular body, while the width has closer measures ( Table 1).

Lower canines

The two lower canines show a very similar morphological pattern ( Fig. 3 H-K) but different dimensions ( Table 1).

They have a bent shape with stout and lightly curved root. A high cingulum is clearly visible at the base of the enamel and on the internal side we can see a modest longitudinal depression that continues on the root. The enamel appears crumpled with typical wrinkles and little furrows.

Upper canine

The upper canine has a very modest degree of bending ( Fig.3L, M ). Like the inferior canines, it appears crumpled and wrinkled. An anterolateral depression is present and extends for about ⅓ longitudinally. A more evident groove can be observed on the anterior side, departing from the cingulum up to almost the point of the tooth. The high cingulum decreases on the lingual side.

P4

The upper carnassial has three roots ( Fig.3 N-P). The tooth is completely unworn suggesting that it could belong to a young, sub-adult individual.The paracone is the most developed cusp.It rises in the middle of the tooth, slightly displaced on the labial side. The blade departs from the paracone, gently descending and reaching the metastyle after forming a slightly curved margin.The protocone area is better represented as a concavity surrounded by enamel swelling forming a cingulum. A very little cusplet rises from the enamel. The cingulum continues on the lingual side creating a very low hypocone. When the cingulum reaches the medial point of the tooth, it descends rapidly and then rises up again, forming an evident inflectional point. Then it almost reaches the metastyle. On the buccal side there is a light cingulum that follows the lower margin of the dental crown.

Left humerus

A magnificently preserved left humerus ( Fig. 4 ) provides further evidences on the postcranial skeleton anatomy of Pannonictis .

The diaphysis has a straight appearance in anterior view, while in lateral (and medial) view it is markedly curved backwards and, in its distal end, frontally. The latter curvature is given by the expanded epicondylar (or supinator) crest ( Fig.4 ).

The proximal epiphysis has a round articular head, projected cranially. The diaphysis is transversely compressed and marked by strong ridges: the deltoid ridge is distinct and strong. The pectoral ridge is less stronger than the deltoid one and is present almost throughout the length of the diaphysis. The lateral epicondylar (or supinator) crest is laterally very expanded and extends proximally from the margin of the lateral ecycondyle to reach about 2/3 of the diaphisys. In medial and lateral views it contributes the pronounced curved lateral profile ( Fig. 4C, D ).

On the proximal end, the lesser tuberosity is large and is separated from the greater tuberosity by a marked deep intertubercular groove.

The articulation of the distal epiphysis is wide. The capitulum (or medial condyle; for articulation with the radial head) is relatively wide on the anterior face. The trochlea (or lateral condyle) is narrow and relatively deep. The olecranon fossa is deep and wide. The supracondylar foramen is large, elongated proximo-distally. The radial fossa is deep and wide. The lateral epicondyle is much less laterally extended than the medial one, but it is antero-posteriorly developed and prominent due to the distal extension of the above-mentioned welldeveloped epicondylar crest. The medial epicondyle is well developed and extended medially.

Figures

FIG. 3. — A, B, Pannonictis nestii (Martelli,1906), holotype:left hemimandible (IGF 916) from Upper Valdarno in lingual (A) and labial (B) views;C-G, Pannonictis nestii from Pirro 10: left hemimandible (PU120257) in lingual (C) and labial (D) views; juvenile right hemimandible (PU 126946; reversed pictures) in lingual (E), occlusal (F) and labial (G) views; H-P, Pannonictis nestii from Pirro 10: H, I, left lower canine (PU 118847) in lingual (H) and labial (I) views; J, K, right lower canine (PU 118848) in lingual (J) and labial (K) views; L, M, right upper canine (PU 118846) in lingual (L) and labial (M) views; N-P, left P4 (PU 120242) in labial (N), lingual (O) and occlusal (P) views. Scale bars: 10 mm. Photos of elements A and B, courtesy of Saulo Bambi (Museo di Storia Naturale, Firenze).

FIG. 4. — Pannonictis nestii (Martelli, 1906) from Pirro 10, left humerus (PU 129095) in anterior (A), posterior (B), lateral (C) and medial (D) views. Scale bars: 10 mm.