Caenomeryx filholi (Lyddeker) Berger, 1959

Blondel, Cecile, 2005, New data on the Cainotheriidae (Mammalia, Artiodactyla) from the early Oligocene of south-western France, Zoological Journal of the Linnean Society 144 (2), pp. 145-166 : 160-162

CAENOMERYX FILHOLI (LYDEKKER, 1885A)

1885a Caenotherium Filholi Lydekker , p. 63.

1885b Caenotherium filholi Lydekker , p. 176.

1936? Caenotherium Filholi Lydekker ; Hürzeler, p. 102.

1937 Caenotherium commune aff. elegans Pomel; Dehm, p. 353.

1959 Caenomeryx filholi (Lyddeker) Berger, 1959: 3 .

Holotype: Skull ( BMNH M1399 ). Age and precise locality unknown (Old Quercy collections).

Diagnosis: Diastema between P/1 and P/2 and between C and P1/. Premolars are not shortened. Premaxillo-frontal suture variably present. The ethmoidal slit is irregular. The mandible is high, massive and long ( Berger, 1959).

Referred material: Pech Crabit: two maxillary fragments, one with left P2/-M3/ ( PCT 417), and one with right P3/-P4/ ( PCT 390), two isolated left P3/ ( PCT 392, PCT 418), 12 mandibular fragments, two with left P/2-P/4 ( PCT 437, PCT 453), two with left P/2-M/1 ( PCT 928, PCT 933), one with broken left P/2-M/2 ( PCT 445), one with right P/2-P/3 ( PCT 936), one with right P/3-M/3 ( PCT 449), three with left P/3-P/4 ( PCT 456, PCT 959, PCT 984), one with left P/3-M/2 ( PCT 971), and one with right M/1-M/3 ( PCT 299).

A

Measurements: See Table 6. For C. filholi , the Kolmogorov- Smirnov and Shapiro- Wilk tests confirm normality for P/3 from Pech Crabit (N = 10, K–S, d = 0.201 P> 0.20, W = 0.928 P = 0.386, V = 6.18).

Description

Upper dentition: The material displays all the features that characterize the genus: the double-rooted P2/ is short. It has a wide lingual talon with a well developed lingual cusp. The P3/ is triangular and short. The median protocone is well developed, while the parastyle and the metastyle are prominent on the ectoloph ( Fig. 4C ).

Lower dentition: The single-rooted P/1 is separated from P/2 by a diastema 3.3 mm long ( ITD 944d). The median tubercle of P/2 is poorly developed, and the short P/3 displays a paraconid strongly carried towards the lingual side ( Fig. 4D ).

Comparison: The material reported here represents a species that is larger than C. procommunis ( Tables 5, 6) and similar to the Gaimersheim species ( MP 28) C. filholi in its characters. Moreover, it is very similar to C. filholi forma b described by Berger (1959) in its upper teeth dimensions. However, the mandibular teeth are somewhat smaller.

Discussion

The older age of the Pech Crabit and Itardies localities ( MP 23) might explain the size difference between the specimens from Pech Crabit and from Gaimersheim, although this does not justify the distinction of this form at the specific level. The C. filholi lineage may have evolved between MP23 and MP28 concurrently with C. procommunis . Nothing in the collection indicates the presence of Caenomeryx before MP22. I consider that the C. filholi lineage present near MP23 originated from that of P. cadurcensis because of numerous similar features. The presence of P. cadurcensis and C. filholi near MP23 contradicts the idea that these two species are present at chronologically distinct levels ( Berger, 1959).

Figures

Figure 4. Caenomeryx cf. procommunis. A & B, occlusal view. A, right P2/-P3/ (PCT 420). B, left P/2-M/2 (PCT 951). C. filholi. C & D, occlusal view. C, left P2/-P4/ (PCT 417). D, left P/2-M/1 (PCT 933). Cainotherium sp. E, left P2/-M3/ (PCT 416). Scale bar = 1 mm.