Kaszab Zoltán (szerk.): A Magyar Természettudományi Múzeum évkönyve 70. (Budapest 1978)

Jánossy, D.: Larger mammals from the lowermost Pleistocene fauna, Osztramos, Loc. 7. (Hungary)

This relatively rich and mainly well-preserved material allows a more detailed analysis. The small dimensions of the remains are remarkable at a first glance. I had the opportunity to compare the remains directly with the skull and mandible of "Ursus ruscinensis DÉPERET" (University of Lyon) deriving from the brick-works of Chefdebien, Perpignan (see DÉPERET, 1897, planche 3; VIRET, 1954, p. 45). Table 1 shows that most of the measurements of the teeth in the Osztramos specimen agree with those of the French one. Not even the morphology of molars differ in both specimens, only minor differences exist obviously due to the individual variation. The canines are weaker and the size of the mandibule is smaller in the Osztramos specimen, either due to the sexual dimorphism or individual variation. The mandible of the Perdignan specimen is broken, thus no length measurement is available. The corresponding measurement (from the front margin of the alveolus of the canine to the processus condyloideus) in the Osztramos bone is about 170 mm. Table 1. Comparative measurements of small Plio-Pleistocene Ursus remains (mm) "Roussillon" (Perpignan) Osztramos, Loc. 7 Length X width of the P

1 14X9.5 13X9.5 Length X width of the M

1 18X 14 18X 14 Length X width of the M~ 24.6 X 14.5 24X 14 Length of upper diastema cca. 24 cca. 24 Length X width of the P

4 13.3X6.7 11.1X6.1 Length X width of the M

x 20.0X9.2 21.0X9.5 Length X width of the M

2 19.5X 12.0 18.0X12.0 Length X width of the M

3 16.0X 12.5 (germ : see text) Height of mandible below the M, 38 30 Length of lower diastema 30 22 Besides the cranial and tooth material, the humerus fragments are of special interest, owing to their dimensions and by possessing a foramen entepicondyloideum, although no supratrochlear foramen is present. The entepicondylar foramen may be considered as a primitive feature, appearing e.g. in the geologically older Canids, Ursids and Amphicyonids, etc. I have not found it in the recent species Tremarctos ornatus and Selenarctos tibetanus. In the Lower Pleistocene material VIRET (1954) found this foramen in the humerus of Ursus etruscus, though the dimensions of the bone were considerably larger. The distal width of the humerus in the Saint Valuer material measures cca 94 mm, the smallest width is on the trochlea 61 mm. The same measurements in the Osztramos material are 63 and 43 mm, expressing a considerable difference in size between the two evolutionary lines. The literature on Lower Pleistocene bears is very vast and puzzling. Most authors suppose two evolutionary lines: a small one with slender extremity bones: Ursus boeckhi, minimus, arvernensis, ruscinensis, stehlini-dehmi etc. and a large one with more robust extremity bones: Ursus etruscus. VIRET (1954) does not accept the presence of this two evolutionary lines and speaks only of a homogeneous Ursus etruscus with great variation in size. KRETZOI (1954) indicated Ursus boeckhi to represent a distinct evolutionary line, possessing in the M

L a primitive, Canidlike metaconid. The small bear of Osztramos 7 evolutionarily somewhat higher is represented in the Hungarian Lower Pleistocene (in the collection of the Hungarian Natural History Museum, Budapest) by the following remains: 1. An upper canine from Püspökfürdő. Total length measuring 56 mm (root and crown together); the length of the crown (outer side, unworn) 29 mm, the maximum width on the boundary of the crown and root 16 mm. •— 2. A right M

3 from Beremend, with the length and width 17x 13 mm. For comparison: the germ of the M

3 in the Osztramos 7 material measures about I6X 12 mm. These two remains were labelled by KORMOS at that time as „Helarctos böckhi" (sic!). I compared the very nice remains of Osztramos 7 with the dentition and humerus of Helarctos malayanus, Tremarctos ornatus and Selenarctos tibetanus. Neither the dentition of Helarctos, nor that of Tremarctos can be compared with the fossil material. Only Selenarctos resembles in outline the extinct form, though does not possesse an entepicondylar foramen in the humerus. Thus, the designation "Helarctos'" must be newly refused (STEHLIN 1933). Summarizing we have to establish, that the two (or more) evolutionary lines in Pleistocene bears seem to be acceptable. The technical name of the small form of Osztramos 7 is, as far as our