Kennetheredium sp.

Sigogneau-Russell, Denise, 2003, Holotherian mammals from the Forest Marble (Middle Jurassic of England), Geodiversitas 25 (3), pp. 501-537 : 522-524

? Kennetheredium sp.

MATERIAL EXAMINED. — BMNH J.428, J.515, J.532, J.801, right lower molars; BMNH J.214, J.846, left lower molars.

Six more lower molars could belong to a closely related taxon: but the low situated talonid is more extended labio-lingually than antero-posteriorly; it is thin and recurved labially in the most complete tooth. The attribution of these teeth to the preceding taxon meets with the other following difficulties.

BMNH J.214 (left) has a barely sloping lingual cingulum which does not underline the whole paraconid, starting only at its posterior end; the paraconid is anteriorly inclined; an f cusp is present; the metacristid may have been present, in which case this particular trigonid would not fit here. On J.428 (right; Fig. 17B ) the cingulum is extremely faintly indicated, but the erosion of the enamel might explain this situation; the distal end of the talonid is recurved upwards distally as in? Kennetheredium leesi n. gen., n. sp. J.430; there is a strong cusp f. The roots are slightly unequal at the expense of the anterior root (a situation opposite to that of the amphitheriids). J.801 (right) lacks a lingual cingulum; this may be due again to the absence of enamel. It has a high and narrow trigonid, with a completely transverse posterior face and no distal metacristid, at least in the present state of preservation. An antero-labial cingulum may have been present. Roots were subequal. J.846 (left) is a posterior half of a molar with uncertain charac-

a b c d

ters except a possible lingual and labial cingulum and the same type of talonid. J.532 (right) might also have had a complete lingual cingulum, now eroded; however it differs from the other teeth considered above by the equally high, parallel, tubular para- and metaconid; and the former is not inclined forwards. Finally J.515 (right; Fig. 10B ) is slightly larger and more stocky; the lingual cingulum is very faint and incomplete under the metaconid; cusp f was smaller. There was no metacristid ; the talonid, of which the occlusal border is abraded, is recurved labially while the paraconal sulcus is oriented rather vertically. The roots were unequal at the expense of the posterior one. It is clear that these last two teeth, whatever their shared features, cannot belong to the same taxon .

On J.515, there are two independent wear facets posteriorly, one on the metaconid, one on the protoconid; on this same tooth the anterior face of the protoconid is worn; so is f, a cusp less extended than on the Kennetheredium n. gen. specimens. The paraconal sulcus as well as the antero-labial face of the talonid are deeply incised.

Figures

FIG. 17. — Lower molars; A, Kennetheredium leesi n. gen., n. sp., holotype BMNH J.746, × 25; B,?Kennetheredium sp., BMNH J.428, × 26; C,?Kennetheredium leesi n. gen., n. sp., BMNH J.430, × 26; a, labial view; b, lingual view; c, posterior view; d, anterior view; e, occlusal view.

FIG. 10. — Lower molars; A, Palaeoxonodon sp., BMNH J.702, × 22; B,?Kennetheredium sp., BMNH J.515, × 20; C, Palaeoxonodon sp., BMNH J.802, × 25; a, labial view; b, lingual view; c, posterior view; d, anterior view; e, occlusal view.