Berrulestes pellouini, Hooker & Russell, 2012

Hooker, Jerry J. & Russell, Donald E., 2012, Early Palaeogene Louisinidae (Macroscelidea, Mammalia), their relationships and north European diversity, Zoological Journal of the Linnean Society 164 (4), pp. 856-936 : 877-880

BERRULESTES PELLOUINI SP. NOV.

( FIGS 8 , 11C, D , 12A–H, 14)

vp 1964 Adunator lehmani Russell : pl. 3, fig. 1d.

Etymology: After Monsieur J.-L. Pellouin for finding key specimens of the species.

Holotype: LM 1, MNHN.F.I-567, bed 5, Berru.

Paratypes: RM 1 , MNHN.F.CR-111-Ph; two LM 3, MNHN.F.CR-377, CR-548; two RP 4 s, MNHN.F.CR- 1135-Pn, CR-39- MD; LM 1 , MNHN.F.CR-143-Pn; RM 1 , MNHN.F.CR-1154-Pn; LM 2, MNHN.F.CR-1719-Pn; RM 2 , MNHN.F.CR-1425-Pn; LM 3, MNHN.F.CR- 15928; all Cernay.

LM 2, MNHN.F.I-253; two LM 3 s, MNHN.F.BR-3, BR-6; all bed 5, Berru.

Referred material: RM 1, MNHN.F.CR-149-Pn; LM 2, MNHN.F.CR-4428; RM 2, MNHN.F.CR-1126; all Cernay.

Cast in MNHN.F: RDP 4, CR-44-Lass, Cernay.

Age and distribution: Sables de Châlons-sur-Vesle supérieurs, late Thanetian, Late Palaeocene, Cernay and Berru (bed 5), France.

OR, observed range; SD, standard deviation; V, coefficient of variation (SD as percentage of the mean).

Diagnosis: Small Berrulestes , mean length of M1 2.55

mm. Cusps of cheek teeth acute. P 4 with metaconid extending mesially (shared with B. phelizoni ). M 1 postcingulum and metacingulum confluent, postmetaconule crista not reaching them. M 1 hypocone subequal in height with protocone (shared with B. phelizoni ). M 1 with shallow postflexus (shared with B. poirieri ); crest linking postprotocrista to hypocone. Lower molars with paraconid cuspate, half the height of the metaconid on M 1 in lingual view. Lower molar precingulid shelf-like, bulging mesially (shared with B. phelizoni ). M 1–2 with protoconid taller than tooth width. M 1 talonid longer and wider than trigonid.

Description

M 1: One specimen represents the diagnostic upper molar characters (Fig. 12A). It is fairly heavily worn, so it is difficult to judge relative heights of cusps. The characters of the confluence of the postcingulum and metacingulum bypassing the postmetaconule crista and the presence of a postprotocrista–hypocone crest, although not testable for variation in B. pellouini , do not occur in any B. phelizoni M 1. They are thus judged reliable. The specimen also has a short premetaconule crista and no postparaconule crista.

M 3: The single specimen is 1.28 mm long by 2.04 mm wide. It is similar to M 3 of Pa. dolloi but slightly larger, with a more expanded protocone lobe and weak postprotocrista (Fig. 12B). There is a large parastyle and a complete ectocingulum. The postcingulum lacks a hypocone.

P 4: Both specimens show a metaconid extending mesially right to the valley behind the paraconid ( Figs 11C, D , 12C). This extent is slightly more than

› Figure 12. Scanning electron micrographs of gold-palladium coated epoxy casts of teeth of Berrulestes pellouini gen. et sp. nov., late Thanetian (A–H), and Berrulestes sp. 1 , Châlons-sur-Vesle Formation, middle Thanetian (I), both France. A, RM 1, Cernay (MNHN.F.CR-111-Ph). B, LM 3, Cernay (MNHN.F.CR-377). C, RP 4 (reversed), Cernay (MNHN.F.CR-39- MD). D, holotype LM 1, bed 5, Berru (MNHN.F.I-567). E, RM 2 (reversed), Cernay (MNHN.F.CR-1425-Pn). F, LM 3, bed 5, Berru (MNHN.F.BR-6). G, LM 2, Cernay (MNHN.F.CR-1719-Pn). H, LDP 4, Cernay (MNHN.F.CR-52-Pn). I, LM 1, Châlonssur-Vesle (NHMUK.M84835). Views are: buccal (A1, B1, C2, D2, E2, F2, G2, H2, I2), occlusal (A2, B2, C1, D1, E1, F1, G1, H1, I1), and lingual (C3, D3, E3, F3, G3, H3, I3). Scale bar = 2 mm.

›

in B. phelizoni , but is also subject to variation in B. pellouini . Otherwise the only difference from B. phelizoni is size. The postcristid is strong, subsuming the hypoconulid. Like B. phelizoni , there is variation for structure of the paraconid and entoconid ( Fig. 11C, D ).

M 1: The attachment position of the cristid obliqua to the back of the trigonid is variable. In two specimens it is essentially at the midline, in two others it is more buccal (Fig. 12D1). The range of variation resembles that of B. phelizoni . There is also slight variation in crown height as evidenced by two unworn specimens, but both are taller (Fig. 12D2, D3) than in B. phelizoni .

M 2: There is variation in height of the paraconid. It ranges from half to less than one third of the height of the metaconid in lingual view (Fig. 12E3, G3). There is also variation in strength and length of the precingulid (Fig. 12E2, G2). The talonid is narrower than the trigonid in all the specimens (Fig. 12E1, G1). Like M 1, there is variation in the attachment position of the cristid obliqua to the back of the trigonid. One specimen is unusual in appearing slightly lower crowned than the other M 2 s, thus more like B. phelizoni in this respect, although wear prevents measurement. In addition, the postentocristid is absent and the paraconid is the lowest of all the M 2 s (Fig. 12G1, G3).

M 3: The three specimens have relatively elongate talonids with hypoconid, entoconid, and hypoconulid as distinct cusps, the entoconid being more distal than the hypoconid (Fig. 12F). The paraconid is very small. Two have a mesially convex premetacristid like M 1–2, in the other it is straight. All have a precingulid that extends distally round the entire protoconid. For size see Figure 14 .

DP 4: Five teeth have similar morphology to DP 4 of B. phelizoni (Fig. 12H), but are substantially smaller, ranging from 2.08–2.31 mm in length (mean 2.23) and 1.23–1.45 mm in talonid width (mean 1.33). They differ in that the lingual protoconid rib is less salient and extensive in the trigonid basin. There is some variation in the position of the contact of the cristid obliqua with the back of the trigonid, but in all cases it is substantially buccal. The precingulid may extend distally half way round the hypoconid (Fig. 12H1, H2) or it may be restricted to the mesial half of the protoconid, with an additional small section adjacent to the hypoflexid.

Figures

Figure 8. Scatter diagrams of Ln length vs. Ln width in millimetres of cheek teeth of Walbeckodon, Paschatherium, and Berrulestes from Cernay, Berru and Châlons-sur-Vesle. A, M; B, M; C, P; D, M1. Hollow square = Cernay; hatched 1 2 4 square = Paschatherium dolloi, Cernay; hollow circle = bed 5, Berru; solid circle = bed 4, Berru; solid triangle = Berrulestes sp. 1, Châlons-sur-Vesle. The cross hairs in A, B, and D give the range of measurements of Pa. dolloi from the Dormaal type assemblage from López-Martínez et al. (2006: table 2).

Figure 11. RP4s (reversed) of Berrulestes phelizoni (A, B) and Berrulestes pellouini (C, D), shown as from left side, to show individual variation. Views are: occlusal (A1, B1, C1, D1), buccal (A2, B2, C2, D2), and lingual (A3, B3, C3, D3). A, MNHN.F.I-602; B, MNHN.F.CR-1448; C, MNHN.F.CR-39-MD; D, MNHN.F.CR-1135-Pn. Scale bar = 2 mm.

Figure 14. Scatter diagram of length versus trigonid width in millimetres of M3 of species of Berrulestes, to show the different proportions of Berrulestes poirieri sp. nov. Hollow circle = Berrulestes pellouini sp. nov.; solid circle = Berrulestes phelizoni sp. nov.; hollow square = B. poirieri sp. nov.