Comparative craniometrical analysis and distributional patterns of medium-sized horseshoe bats (Chiroptera: Rhinolophidae) in Bulgaria (original) (raw)
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Generalized scheme for description of craniometric characters of mammals is presented, with detailed analysis of each group of signs (overall, braincase, rostrum, mandible). Unified system of acronyms for designation of measurements is proposed and applied. Partial schemes are presented, separately for each typical representative of main orders known in the fauna of Ukraine: rodents (Sylvaemus), bats (Eptesicus), insectivores (Crocidura), carnivores (Mustela), ungulates (Capreolus). All partial schemes are illustrated by photos with designations of key points for measurements. Each partial scheme includes about 15–20 metric features. Problems of “excess”, small-sized and group-specific features as well as size of samples are discussed. The application of description of craniometric variation was considered: diagnostics of closed species, differentiation of age and sex groups, analysis of geographic variation, growth changes of features, study of evolutional and ecomorphological diff...
Variability of skull morphometric characters in Nycetereutes procyonoides
Biologija, 2013
The raccoon dog (Nyctereutes procyonoides) is a medium-sized carnivore which spread over Eastern, Central and Northern Europe after its introduction into the European part of the former Soviet Union. The aim of the present study was to perform osteometrical analysis on Tadas Ivanauskas Zoological Museum specimens of raccoon dogs skulls collected in 1957, and compare the results of analysis with those obtained in 2005 in Lithuania and with osteometrical parameters from aboriginal Amur and Khabarovsk populations. In total, 36 skulls of raccoon dogs (20 males and 16 females) were used to examine any variations of skull morphometric characteristics with respect to sex. In total, 7 measurements were taken on each skull of the raccoon dog. The results of the analysis showed that males were larger than females and indicated some differences among raccoon dog skulls collected in different regions of Lithuania. The maximum condylobasal length of the Nyctereutes procyonoides found in 1957 and 2007 Lithuanian populations was larger than in aboriginal populations (Korablev et al., 2013). The mean values of measurements on interorbital constriction (IC), postorbital constriction (PC) and mandible height of skulls in the present study were lower that reported in specimens from the native range of the raccoon dog. The results of comparison analysis revealed higher value of index of raccoon dog skulls in males from Amur, while the lowest indices were observed in specimens from Khabarovsk and Lithuania.
International Journal of Morphology, 2014
Morphological variation of the ramus mandibulae of wild Sus scrofa was described and correlated to sex and age differences. Young forms (n=27, 15 males, 12 females) and adults (n=23, 13 males, 10 females) were analyzed through Geometric Morphometrics (2-D) to assess differences between groups. We found significant differences between age-and sex-related shape variations at ramus mandibulae level. Young wild boars present bulky angular process with backward oriented coronoid process, while adults show slender jaw vertical ramus, and orthogonally oriented coronoid process. The ramus mandibulae in female wild boars is more robust and bulky than in males. The morphological changes between young and adult forms are related to alterations in the osteo-muscular jaw complex along wild boars ontogeny. The jaw morphological variations observed in adult wild boars could also be related to dietary differences between sexes. KEY WORDS: Mandible; Ontogeny; Sexual Dimorphism; Wild boar. HOHL, L. S. L.; SICURO, F. L.; AZORIT, C.; CARRASCO, R. & ROCHA-BARBOSA, O. Age and sex-related geometrical variation of Ramus mandibulae of Sus scrofa's (Mammalia: Artiodactyla) jaws. Int. J. Morphol., 32(4):1282-1288, 2014. HOHL, L. S. L.; SICURO, F. L.; AZORIT, C.; CARRASCO, R. & ROCHA-BARBOSA, O. Variaciones geométricas de la Ramus mandibulae en mandíbulas de Sus scrofa (Mammalia: Artiodactyla) según edad y sexo. Int. J. Morphol., 32(4):1282-1288, 2014.
tCranial size and shape variation of the greater horseshoe bat Rhinolophus ferrumequinum from territoriesin Serbia and Montenegro was examined using geometric morphometric methods. Statistically significantsize and shape differences among specimens from distinct geographic regions (the Carpatho–Balkanides,the Internal and External Dinarides) were observed. Bats from the Carpatho–Balkanides have the small-est crania, while those from the External Dinarides have the largest ones. Compared to specimens fromthe Carpatho–Balkanides, bats from the other two regions have crania wider in the temporal and elon-gated in the facial region, while the basicranial region is smaller. Our analysis of sexual size dimorphismrevealed no statistically significant differences between males and females. Even though significant sex-ual shape dimorphism was observed, cranial shape differences among bats from different geographicregions exceeded those between sexes. We also found that size and shape vary with climatic factors.Allometry has statistically significant effect on cranial shape variation and somehow contributes tocovariation between cranial shape and environmental variables. Although the examined bats were from arelatively small territory, we have provided new insights into important issues like geographic variation,sexual dimorphism and allometry in this species.
Shape and age variation in dentition of Paleogene extinct native South American ungulates (Notoungulata) has been traditionally described using qualitative and quantitative approaches, and has played a controversial role in the systematics of several groups. Such is the case of the Notopi-thecidae, a group of notoungulates with low-crowned teeth, known from the middle Eocene of Patagonia (Argentina). In this group, as well as in other contemporary families, extreme morphological changes associated to increasing dental wear were originally assumed to represent taxonomic differences; thus, dozens of species were erected, clearly reflecting the difficulty of defining discrete characters. In this contribution, a total of 89 upper molars and 91 lower molars were analyzed distributed in two factors, wear and species; three species of notopithecids were considered as study case, Notopithecus adapinus, Antepithecus brachystephanus, and Transpithecus obtentus, based on the large and well-identified sample of upper and lower molars for each species. We have coupled geometric morphometric analyses with traditional comparative methods to get a better understanding and interpretation of both the changes in tooth shape contour and the link between shape and ontogeny. In addition, we evaluate the utility of this approach to identify which changes are strictly wear-related and also test the qualitative characteristics used for diagnosing and differentiating notopithecid species. Our study yielded consistent results when applying independent geometric morphometric analyses on complex structures such as brachydont molar teeth. The landmark data is highly congruent with alternative sources of evidence, such as morphological studies using discrete characters. In notopithecid species, wear is the main factor affecting molar shape, followed by species (in lower molars) and allometry; in addition, lower teeth morphology is more definitive in separating species than upper molars, a fact that entails a key point for systematic studies of Paleogene brachydont notoungulates. however, a general consensus regarding the mechanics of tooth wear and its causes (e.g., the historical dichotomy of phytoliths versus exogenous grit) has not yet been
Revista mexicana de …, 2008
The occlusal pattern of the cheek teeth has traditionally been one of the most widely used features to determinate equid species. Nevertheless, its large ontogenetic variation and subjective assessment of characters has diminished its reliability. For this reason, many workers have reduced emphasis on the cheek teeth in identifying equid species and have turned their attention to other skeletal elements. We re-emphasize the analysis of the oclusal pattern to determine the number of equid species present in the Cedazo local fauna, Aguascalientes, Mexico. In contrast to previous studies, we only analyzed cheek teeth with an equivalent stage of wear and developed a computer program that integrates a digital image processor to analyze the occlusal pattern and also to take measurements of different features of the occlusal surface. Selecting teeth with an equivalent stage of wear reduced the usable sample size signifi cantly. For this reason, the analysis concentrated on the third upper premolars (P 3), because they represent the largest sample size. Specimens of Equus caballus, E. asinus and hybrids were also included to serve as controls. Principal Components and Canonical Discriminant Functions analyses were performed. The extant species were positively discriminated. Moreover, these analyses suggest the presence of two distinct P 3 morphotypes for the fossil sample studied, which indicate the possible occurrence of at least two separate equid species for the Cedazo local fauna. However, it is prudent to collect more material and evaluate these results with a larger sample size and using the remaining tooth positions. The computer program developed in this study serves as a useful tool for analyzing the occlusal pattern of equid cheek teeth.