Search results for "Geometric morphometric"

Ecomorphological inferences in early vertebrates: reconstructing

2017

Our knowledge about the body morphology of many extinct early vertebrates is very limited, especially in regard to their post-thoracic region. The prompt disarticulation of the dermo-skeletal elements due to taphonomic processes and the lack of a well-ossified endoskeleton in a large number of groups hinder the preservation of complete specimens. Previous reconstructions of most early vertebrates known from partial remains have been wholly based on phylogenetically closely related taxa. However, body design of fishes is determined, to a large extent, by their swimming mode and feeding niche, making it possible to recognise different morphological traits that have evolved several times in no…

L’IMPIEGO DELLA MORFOMETRIA GEOMETRICA E IL CONTRIBUTO DELLA CITOGENETICA NELLO STUDIO DELLA TRIBÙ CERCOPITHECINI (ORDINE PRIMATES)

The tribe Cercopithecini is a large and colourful taxon of African primates. Together with the tribe Papionini, it belongs to the subfamily Cercopithecinae (Gray, 1821). Despite several studies carried on the present species of Cercopithecini (guenons and sister genera), up to date a strong and clear systematics is missing. The evolutionary relationships inside the tribe are controversial, as are the numbers of genera and species. This lack prevents our full comprehension of the evolution of the tribe. We decided to investigate the tribe Cercopithecini through the use of two methodologies: geometric morphometrics and cytogenetics. The geometric morphometric survey was conducted on 1126 cran…

Species identification of the psammophilous tenebrionid beetles Phaleria acuminata Juster, 1852 and Phaleria bimaculata (Linnaeus, 1767) from central…

2013

Dominating global arid environments, from desert to coastal dunes, most Tenebrionidae are highly specific in their habitat preferences and display limited dispersal potential, thus exhibiting a remarkable degree of regional genetic and morphological differentiation. The tenebrionid genus Phaleria is speciose and widely distributed, with P. acuminata and P. bimaculata having a wide Mediterranean distribution, with numerous morphological differentiations at population level, often described as different taxa of doubtful taxonomical significance. In order to investigate the variability of the central Mediterranean populations of P. bimaculata and P. acuminata and to compare the results obtaine…

Comparative morphometrics of sharpsnout seabream (Diplodus puntazzo Cetti, 1777), reared in different conditions

1999

The same genetic stock of sharpsnout seabream (Diplodus puntazzo), cultured in different conditions (lot A, monoculture tank; lot B, monoculture offshore cage; lot C, polyculture tank), was analysed using geometric morphometrics in order to detect changes in shape. Rearing in the offshore cage (lot B) had a significant effect on shape variation when compared to rearing in the two enclosed tanks (A and C). Fish from the tanks show a higher frequency (43.7% in lot A and 37.5% in lot C) of the so-called ‘goitred’ and ‘dorsal flat’ forms, their deformations shown by displacements in the corresponding landmarks of the infraopercular and dorsal areas. In contrast, the so-called ‘belly’ fish were …

L'ornementation des bracelets de l'âge du Bronze européen : analyse descriptive et perspectives

2013

This paper discusses the ornamental patterns of metal bracelets worn on the arms and legs of people during the European Bronze Age. A method has been specially created to study geometric patterns. Some sets of metal bands (bracelets métalliques) of Bronze Age reach a high level of complexity due to the use of combined patterns in an overall structure. This paper deals with an experimental criterion concerning this phenomenon. The methodology, developed for the purpose i.e. the experimental criterion developed for the purpose of this study, was to extract geometric patterns from the original media. The principle is to release the geometrical compositions of the deformations induced by the mo…

The Human Biodiversity in the Middle of the Mediterranean. Study of native and settlers populations on the Sicilian context

2020

[IT] Negli ultimi 200.000 anni, la specie umana si è diffusa in tutta la Terra, adattando la sua morfologia e fisiologia a un'ampia gamma di habitat. Lo scheletro umano ha quindi registrato i principali effetti ambientali e di conseguenza i reperti scheletrici assumono grande importanza nell'indagine dei processi evolutivi. Oggi le moderne tecniche di indagini quantitative delle principali caratteristiche morfologiche consentono di metterle in relazione con la variabilità genetica. La posizione geografica della Sicilia, l'isolamento e la sua lunga e dinamica storia di colonizzazione (diversi e numerosi contributi culturali e biologici) hanno creato un contesto peculiare che consente uno stu…

Morphological variability in and distributional data on phaleria bimaculata populations from islands of the central mediterranean area

2011

This study aimed to collect new taxonomic and distribution data on Phaleria bimaculata (L.) (Coleoptera Tenebrionidae) from Sicily (southern Italy), the circum-Sicilian islands and the Maltese archipelago. Particular attention was paid to the diagnostic morphological features observed in the populations sampled, focusing on the subspecies Phaleria bimaculata marcuzzii Aliquò. P. bimaculata individuals were collected from 20 different locations, of which 2 were located in the Sicilian mainland, 9 in circum-Sicilian islands and 9 in the Maltese Islands. In addition, four Phaleria acuminata Kuster populations were also recorded along southern Sicilian shores. The two Phaleria species were neve…

Differences in inner ear asymmetry levels between slow-moving and fast-moving primates

2021

International audience; The vestibular system of the inner ear, highly involved in maintaining balance during activities and positional behaviour of animals, has been deeply studied in order to link its morphology with the specific type of locomotion. Previous studies (e.g. Perier et al. 2016, Gonzales et al. 2018) have shown that, in primates, the amount of morphological variation is higher in slow-moving species than in fast-moving ones. These results indicate a lower selective pressure and a reduced functional demand for postural adjustments in the former group, and a higher selective pressure for balance and postural capabilities in the latter. In this study, we assessed if the differen…

ANALYSIS OF THE SEXUAL VARIABILITY IN THE SHELL OF THE SPANISH UPPER CRETACEOUS TURTLE DORTOKA VASCONICA (PAN-PLEURODIRA, DORTOKIDAE)

2021

The present study characterizes the morphological variability related to the sexual dimorphism in the shells of the Spanish Upper Cretaceous turtle  Dortoka vasconica . This study is based on the material from its type locality: Lano, Burgos. Two morphotypes were identified there based on the posterior plastral area as well as two for the anterior plastral lobe. However, a correlation with the previously indicated morphotypes could not be established due to the disarticulation of the specimens and the limited information available on the sexual dimorphism of Pleurodira. The morphological variability previously identified for  Dortoka vasconica  is analysed here through a quantitative approa…

Ecomorphological variation within and among the two marine species of genus Salaria: Salaria basilisca and Salaria pavo (Perciformes: Blenniidae)

2022

In order to highlight the variation of the form due to the presence of different ecological factors, we investigated in this paper the morphological variation between and within the two marine species Salaria basilisca and S. pavo. This study was based on two approaches, the Truss network and the geometric morphometric and involved specimens of both species divided into marine and lagoon samples. The two approaches yielded complementary results showing clear morphological discrimination of the two species Thus, S. basilisca is distinguished by a higher depth and length as well as a higher head with a compressed snout compared to S. pavo which has a shortened body, a lower head and a slightl…