Kennetheredium leesi, Sigogneau-Russell, 2003

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

Kennetheredium leesi n. sp.

HOLOTYPE. — BMNH J.746, left lower molar ( Fig. 17A ).

ETYMOLOGY. — leesi , to acknowledge the essential contribution of Mr A. Lee’s drawings to this paper.

ATTRIBUTED LOWER MOLARS. — BMNH J.379,?J.430, J.514, right lower molars; BMNH J.289,?J.518, J.824, left lower molars.

LOCALITY AND HORIZON. — Clay Bands of the “Kirtlington mammal bed” ( Freeman 1979), Kirtlington Old Quarry, Oxfordshire. Forest Marble (upper Bathonian).

DIAGNOSIS. — As for genus by monotypy.

DESCRIPTION ( Fig. 17A, C )

This taxon would be represented by at least seven teeth with a complete and sometimes denticulated lingual cingulum. The latter is quite different from that of the three teeth mentioned above (p. 509), in that it slopes regularly from front to back and ends in a low situated talonid. The trigonid is high with closely grouped cusps. The talonid (preserved on three specimens only) is shorter than that in Palaeoxonodon but still relatively elongated and with a short occlusal concavity; it is again labially recurved distally. There is no distal metacristid, only a very short crest at the base of the metaconid limiting labially the talonid surface. Where preserved, the paraconid is slightly inclined forwards and slightly smaller than the metaconid as a consequence of the distally inclined lingual cingulum. The antero-labial cusp (f) is well indicated and occupies the whole anterior base of the protoconid. Moreover, a slight labial cingulum may be present (the type is not preserved low enough). At most, one root is preserved so that the relative proportions of the two roots are uncertain; they were at least subequal if not equal.

The enamel of the holotype tooth not being intact, only the ovale f facet is certain. J.514 has a narrow wear facet on the anterior face of the protoconid which joins that of f and that on the tip of the paraconid, and a wider posterior facet which joins that of the paracone sulcus; the situation is nearly the same anteriorly on J.430. On J.289 the paraconal sulcus goes up to the tip of the metaconid.

This morphology partially resembles that of spalacotheriid symmetrodonts with the notable difference of a longer talonid with a concave occlusal component and the absence of a labial cingulid. Given the fact that the reduction of the talonid is the only apomorphic character of the lower molars recognized for symmetrodonts ( Prothero 1981), the ordinal attribution of the new taxon must remain indeterminate.

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.