Naslov
Femoral morphology of cave bears from Croatia

Autori
Jambrešić, Gordana ; Nikolić, Vasilije ; Paunović, Maja

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
5. Internationales Höhlenbaren-Symposium / Döppes, Doris ; Nagel, Doris - Beč : Institute fur Palaontologie der Universitat , Wien, 1999, 23-24

Skup
5. Internationales Höhlenbaren-Symposium

Mjesto i datum
Bad Mitterndorf, Austrija, 24.09.1999. - 26.09.1999

Vrsta sudjelovanja
Poster

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
Cave bears; limb bones; sex dimorphism; biomechanical indices; radiograph analysis

Sažetak
Investigations of Quaternary Cave sediments in Croatia have intensified in the 1980's when processing of the Upper Pleistocene bears from Vindija cave, Veternica cave, Velika pećina (NW Croatia) and Cerovačke cave (Mt. Velebit) began, tend to reconstructing changes in Quaternary environments. From the geographical aspects, localities can be grouped into two types. Vindija, Velika pećina and Veternica would belong to hill-lowlands type habitat and Cerovačke pećine to mountain type habitat. The location of Cerovačke Caves indicates on different paleoclimatic conditions and different paleovegetation than those in Vindija, Velika pećina and Veternica. In the areas of high mountainous regions of Velebit Mt. with mean winter temperature being several degrees Celsius lower that in lowlands, and much more snowfalls, various ecosystems have been established. These conditions have initiated growth of various types of vegetation, mostly conifers with microrefuges of deciduous trees. Differences in paleoenvironment could possibly caused differences in functional-morphology on Cave bear limbs. Total of 160 femurs has been studied ( 62 - Vidija, 4 - Velika pećina, 27 - Veternica and 67 - Cerovačke pećine). In the Urside the males are always larger than females. Sex-specific size differences can be 10 – 50%, depending about species (Stirling 1993). Analyses of Cave bear size are numerous, almost any skeletal dimension will show the sexual dimorphism in size. Generally, the lengths of male cave bear limb bones are reported to be about 15% longer then female ones (Reisinger, Hohenegger 1998). Statistical methods offer the possibility to prove differences in body size of fossil bears. The method of K-means clustering was applied, the method dominantly different from the other known methods. Knowing the sex dimorphism of bears, we compared 9 measurement variables (A-greatest length, B-length between trochanter major and epicondylus, C-proximal width, D-transversal diaphysis diameter, E-antero-posterior diaphysis diameter, F-distal width, G-antero-posterior caput diameter, H- transversal caput diameter, I-collum-corpus angle of femur) and two groups have been extracted as two clusters: a group of higher values represented the population of males, while a group of lower values represented the population of females (Fig.1). After this analysis the population of males and females have been treated separately in further analysis. Bone Indices (BI) This indices is ratio of diaphysis diameters and length between trochanter major and epicondylus BI= ((D+E)/2) / B. This biomechanical indices may reflect certain types of limb loadind. BI were calculated for femurs from Vindija, Veternica, Cerovačke pećine, and compared with BI calculated for femurs from Conturines (Italy), Herdengel and Gamssulzen (Austria). Values of Cerovačke caves are very similar to values of three Late Pleistocene alpine caves Conturines, Herdengel and Gamssulzen, and different from Vindija and Veternica (fig. 2). Radiograph analysis At some bones from each Croatian locality we take radiographs, and measured outer diameter (D), inner diameter (M), lateral cortical thickens (CL) and medial cortical thickens (CM) at 50% of diaphyseal length, measured from the distal end, perpendicular to the central axis. From this parameters we calculated general cortical indices (CI), medial cortical indices (CIM), lateral cortical indices (CIL) and cortical area (CA). All variables are examined using hierarchical Join (tree cluster) analysis. The denrdrogram show clear separation into two classes, one contains males and the other one females. At the bout classes, Cerovačke caves create a subclasses different from Vindija, Veternica and Velika pećina (fig.3). Results from both analysis lead us to conclusion that Cave bears who was living in different environments (different landscapes and climatic condition) like bears from mountain type site Cerovačke pećine and hill-lowlands type sites Vindija, Velika pećina and Veternica, used its limbs on different way. Differently adapted forms have different limb loading and locomotory patterns. These differences manifest itself on morphology of long bones, in this case on femoral morphology.

Izvorni jezik
Engleski

Znanstvena područja
Geologija

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