Cattle imported from the Iberian Peninsula spread throughout America in the early years of discovery and colonization to originate Creole breeds, which adapted to a wide diversity of environments and later received influences from other origins, including zebu cattle in more recent years. We analyzed uniparental genetic markers and autosomal microsatellites in DNA samples from 114 cattle breeds distributed worldwide, including 40 Creole breeds representing the whole American continent, and samples from the Iberian Peninsula, British islands, Continental Europe, Africa and American zebu. We show that Creole breeds differ considerably from each other, and most have their own identity or group with others from neighboring regions. Results with mtDNA indicate that T1c-lineages are rare in Iberia but common in Africa and are well represented in Creoles from Brazil and Colombia, lending support to a direct African influence on Creoles. This is reinforced by the sharing of a unique Y-haplotype between cattle from Mozambique and Creoles from Argentina. Autosomal microsatellites indicate that Creoles occupy an intermediate position between African and European breeds, and some Creoles show a clear Iberian signature. Our results confirm the mixed ancestry of American Creole cattle and the role that African cattle have played in their development.
Skull size and shape have been widely used to study domestic animal populations and breeds. Although several techniques have been proposed to quantify cranial form, few attempts have been made to compare the results obtained by different techniques. While linear morphometrics has traditionally been used in breed characterization, recent advances in geometric morphometrics have created new techniques for specifically quantifying shape and size. The objective of this study was to compare two morphometric methods for their ability to describe external morphology. For this purpose, 20 skull specimens of adult male Araucanian horses were examined. Two age categories were established (the “mature group”, M3 not fully erupted to moderately worn, n = 7; and the “senile group”, M3 totally erupted and highly worn, n = 13). Both methods showed that there were statistical differences between generations, but discrimination rates were different between methods with the geometric morphometric analysis obtaining a rate of 97.5%. Although linear morphometrics was found to be compatible with geometric morphometrics, the latter was better able to discriminate the two groups and it also provides more information on shape.
Within the genus Macrolophus (Heteroptera: Miridae), the species M. costalis (Fieber), M. melanotoma (Costa) and M. pygmaeus (Rambur) are present in the Mediterranean region on a wide variety of plant species. While M. costalis can easily be separated from the other two by the black tip at the scutellum, M. pygmaeus and M. melanotoma are cryptic species, extremely similar to one another in external traits, which has resulted in misidentifications. M. pygmaeus is an efficient biological control agent, both in greenhouse and field crops. The misidentification of these cryptic species could limit the effectiveness of biological control programs. Although the morphology of the left paramere of the male genitalia has been used as a character for identification of these two cryptic species, there is controversy surrounding the reliability of this character as a taxonomic tool for these species. Using geometric morphometric techniques, which are a powerful approach in detecting slight shape variations, the left parameres from these three Macrolophus species were compared. The paramere of M. costalis was larger and had a different shape to that of M. melanotoma and M. pygmaeus; however, no differences in size or shape were found between the left paramere of M. melanotoma and that of M. pygmaeus. Therefore, our results confirm that this character is too similar and it cannot be used to discriminate between these two cryptic species.
A variety of skull shapes are frequently used for discrimination between animal species, breeds, and sexes. In this study, skulls of three different breeds of cats were examined by the geometric morphometric method, with the aim of revealing skull shape differences. For this purpose, 27 cats (6 British Shorthair, 7 Scottish Fold, and 14 Van cats) were used. The skulls of cats were modeled by computed tomography. Geometric morphometrics was applied using dorsal (8 landmarks, 63 semilandmarks) and lateral (8 landmarks, 63 semilandmarks) skull projections on these models. Centroid size differences between the breeds were statistically insignificant. However, the differences in shape were statistically significant for both the dorsal view and lateral view. Shape variation was less in the British Shorthair than in other breeds. Shape differences generally occurred around the orbit. In the skull of Scottish Folds, the orbit was situated more caudally than in other breeds. The British Shorthair had the largest orbital ring. In dorsal view, the Scottish Fold had the largest orbital diameter. The orbital ring of Van cats was smallest in both dorsal and lateral views. In the canonical variate analysis, it was seen that the breeds were separated from each other. The shape difference in the skull between different cat breeds could be revealed by geometric morphometrics. The results of this study provide useful information for taxonomy.
The distinction between bones of sheep and bones of goats is a difficult issue in zooarchaeology. Several studies undertaken in the past to facilitate this task have relied upon both qualitative criteria and osteometry. Geometric morphometrics has proved to be a powerful tool to evaluate morphological differences in a rigorous and detailed manner. This study aims to analyse variations in the morphology of the calcaneum among sheep and goats based upon two-dimensional geometric morphometrics (GM). Twenty landmarks were selected on the surfaces of 79 calcanea (47 sheep and 32 goats) to calculate the principal components of shape variations among these specimens. Clear interspecific differences in the morphology of this bone were extracted. Most are located on the calcaneal tuber and neck, the sustentacular tali region, the articular surfaces of both the malleolus and the cubonavicular. Furthermore, the use of GM methods has enabled us to assess small but significant amounts of geometric variation that are difficult to measure using traditional morphometric techniques. They provide a new and useful perspective to what is already known in the published literature. Our results shed new light upon the possibility of the existence of qualitative features that may help to distinguish caprine breeds.
31 July 1995 in Journal of Equine Veterinary Science