Crusafontina Gibert, 1975

Sen, Sevket, 2016, Rodents, lagomorphs and insectivores, Geodiversitas 38 (2), pp. 299-314 : 309-310

Genus Crusafontina Gibert, 1975

TYPE SPECIES. — Crusafontina endemica Gibert, 1975 .

Crusafontina cf. endemica Gibert, 1975 ( Fig. 7 A-C)

TYPE LOCALITY. — Can Llobateres 1, Vellès-Penedes Basin, Spain, MN9.

MATERIAL. — Right mandible (MNHN.F.TRQ962) with complete ramus and part of the body bearing m1 (2.12 × 1.21), right mandible (TRQ963) without ramus and with m1 (1.95 × 1.14), left mandible body fragment (TRQ964) with alveoli of m1-m3, all from Küçükçekmece West.

DESCRIPTION

The MNHN collection includes three fragments of mandibles, two of which have m1 and the alveoli of m2 and m3. The third one has only the alveoli of m1-m3. In labial view, the body has rather sub-parallel lines from below m1 to below m3. The ventral margin is flat below the molars, and slightly curved upward toward the angular process. The foramen mentale is positioned at mid-depth either below the protoconid of m1 (2/3) or below its talonid (1/3). There is a second foramen below the anterior root of m2. The masseteric crest is absent on this face. The ascending ramus is high, and forms an angle of 100° with the body. The coronoid process is slightly enlarged and rounded on its tip. The external temporal fossa is well marked in its upper part, while its lower part is rather shallow; the coronoid spicule, which divides this fossa in two parts, is thick and does not reach the distal margin of the coronoid process. The angle of the upper sigmoid notch is about 95°. The angular process is reduced, being faintly marked by the shallow lower sigmoid notch.

The lingual face of the body is smooth and rather flat. On the ramus, the internal temporal fossa is very large, drop shaped, and is deepest at the mid-level of the articular process, or above the occlusal plan of m3, if preserved. The mandibular foramen is situated just below the internal temporal fossa, but separated from it by a thick ridge that connects the lingual alveolar edge to the base of the articular process. On the articular process, the upper and lower articular facets are broadly connected to form a boomerang-shaped single articular facet. Its upper part is rather triangular, while its lower part is oblong. The pterygoid fossa is deep and bordered disto-ventrally by the articular facet, and mesio-dorsally by a ridge that descends from the dorsal part of the articular facet.The articular process is L-shaped in distal view.

The unique preserved tooth, m1, does not show pigmentation. The trigonid covers about 2/3 of the occlusal length. The blades of the protoconid and paraconid form an angle of 105°. The paraconid and metaconid are much lower than the protoconid, the lowest being the paraconid. On the talonid the oblique crest is directed toward the lingual arm of the protoconid. The hypoconid is ridge shaped.The entostylid is separated from the entoconid by a narrow notch. The entoconid crest joins the base of the metaconid. There are two cinguli, the mesial one below the paraconid, and the distal one along the distal margin of the tooth, both being rather weak and low.

The length of alveoli m1-m3 varies between 4.04-4.41 mm, with an average of 4.14 mm (n=3). According to the alveoli, the m2 is two-rooted and smaller than m1. The two small alveoli of m3 (length about 1 mm) indicate that this molar was reduced and lingually displaced.

Figures

FIG. 7. — Insectivores from Küçükçekmece West, Crusafontina cf. endemica Gibert, 1975: A, right m1 (MNHN.F.TRQ963) in occlusal view; B, C, right mandible with m1 (TRQ962) in lateral (B) and medial (C) views. Schizogalerix sp.: D, right m2 (TRQ961) in occlusal view. Scale bar: 1 mm.