Lartetium africanum ( Lavocat, 1961 )

Lartetium africanum ( Lavocat, 1961)

Fig. 4 A, B View Figure 4

Material and measurements.

One right i 1 (L: 1.90) ( IPS-PAM 207-30 ), one left m 1 (L: 1.25; TRW: 0.82; TAW: 0.91) ( IPS-PAM 207-31 ).

Description.

i 1 (Fig. 4 B View Figure 4 ). The i 1 is a bicuspulate element. The root is almost equal in length to the crown. The crown and the root display only an inconspicuous bending between both, almost standing along a straight axis. There is a well-developed cingulid covering the labial base of the enamel.

m 1 (Fig. 4 A View Figure 4 ). The m 1 has a talonid wider than the trigonid, although both parts of the tooth are quite similar in length. The protoconid is the highest cuspid of the tooth, followed by the metaconid and the hypoconid. The entoconid is a small cone-shaped cuspid placed just anteriorly from an almost completely reduced entostylid. The paraconid is quite similar in height to the entoconid. The blades of the protolophid and the paralophid are remarkably notched. The hypolophid and the oblique cristid descend regularly from the hypoconid towards the entostylid, and to the middle height of the protoconid, respectively. A marked labial cingulid outlines the base of the paralophid in occlusal view.

Remarks.

In the preliminary identification of the material ( Tesón et al. 2010), this taxon could only be identified to the tribe level, following the proposal of Furió et al. (2007). Considering the relative lengths of the talonid and trigonid of the m 1, and the slight bending between the root and the crown of the lower incisor, this form was classified as an archaic member of the family Crocidosoricinae , more specifically as an undetermined Oligosoricini species.

The study by Hugueney et al. (2015), describing unpublished material of Lartetium africanum , shed new light on the oldest fossil shrews from the African continent. Beyond the extreme similarities in the morphologies of i 1 and m 1, the measurements of these elements from the Ouarzazate material fall entirely within the range of the Beni Mellal assemblage, as provided by Hugueney et al. (2015): ( FSL 66873 ) m 1: L = 1.26 × TRW = 0.83 × TAW = 0.93; ( FSL 66874 ) m 1: L = 1.20 × TRW = 0.80 × TAW = 0.88; ( FSL 66875 ) m 1: L = 1.28 × TRW = 0.87 × TAW = 0.93; and ( FSL 66876 ) i 1: L = 1.98.

In the absence of any alternative hypothesis that could challenge this ascription, this identification likely indicates a species that persisted in North Africa for several million years without undergoing any remarkable change in size or morphology.