Search results for "Morphometric"

Natural variation of profundal macroinvertebrate communities in boreal lakes is related to lake morphometry: implications for bioassessment

2009

Modern biological assessment of aquatic systems is often based on the reference condition approach, which requires characterization of biota in undisturbed conditions. For this approach, it is essential to recognize the origins and degree of natural variation in communities. We used data from 55 minimally disturbed Finnish lake basins to investigate the natural variation of profundal macroinvertebrate community composition in relation to environmental factors. Partial canonical correspondence analysis showed that most (68% combined, 39% uniquely) of the total explained compositional variation (29%) was correlated with environmental variables insensitive to human activities, especially lake …

Studying bipedal dinosaur trackways using geometric morphometrics

2019

Phenotypic plasticity in haptoral structures of Ligophorus cephali (Monogenea: Dactylogyridae) on the flathead mullet (Mugil cephalus): A Geometric M…

2015

Abstract Evaluating phenotypic plasticity in attachment organs of parasites can provide information on the capacity to colonise new hosts and illuminate evolutionary processes driving host specificity. We analysed the variability in shape and size of the dorsal and ventral anchors of Ligophorus cephali from Mugil cephalus by means of geometric morphometrics and multivariate statistics. We also assessed the morphological integration between anchors and between the roots and points in order to gain insight into their functional morphology. Dorsal and ventral anchors showed a similar gradient of overall shape variation, but the amount of localised changes was much higher in the former. Statist…

Historical biogeography of olive domestication (Olea europaea L.) as revealed by geometrical morphometry applied to biological and archaeological mat…

2003

Aim  This study intends to improve our understanding of historical biogeography of olive domestication in the Mediterranean Basin, particularly in the north-western area. Location  Investigations were performed simultaneously on olive stones from extant wild populations, extant cultivated varieties from various Mediterranean countries, and archaeological assemblages of Spanish, French and Italian settlements. Methods  A combination of morphometrics (traditional and geometrical) allowed us to study both the size and shape of endocarp structure. Concerning shape, a size-standardized method coupled with fitted polynomial regression analysis was performed. Results  We found morphological criter…

Morphometrics of the wood mouse (Apodemus sylvaticus, Mammalia, Rodentia) in the Mediterranean

1995

Abstract Sexual dimorphism, ontogenetic variation and allometric shape changes related to variation in size were considered and eliminated before performing discriminant analyses on geographic variation of Apodemus sylvaticus in central Mediterranean areas. Preliminary multivariate analyses of A. sylvaticus populations showed influences of sex and age in the ordination results. Giantism, i.e. size increase and shape‐related change, was more pronounced on islands like Pantelleria and Marettimo. By principal component analysis, we found an allometric factor which proved statistically correlated to insularity parameters (area, distance from mainland, and altitude) but not to the number of pred…

Developmental integration in a functional unit: deciphering processes from adult dental morphology

2014

The evolution of mammalian dentition is constrained by functional necessity and by the non-independence of morphological structures. Efficient chewing implies coherent tooth coordination from development to motion, involving covariation patterns (integration) within dental parts. Using geometric morphometrics, we investigate the modular organization of the highly derived vole dentition. Integration patterns between and within the upper and lower molar rows are analyzed to identify potential modules and their origins (functional and developmental). Results support an integrated adult dentition pattern for both developmental and functional aspects. The integration patterns between opposing mo…

Temnothorax pilagens sp. n. – a new slave-making species of the tribe Formicoxenini from North America (Hymenoptera, Formicidae)

2014

A new species of the ant genus Temnothorax Forel, 1890 – Temnothorax pilagens sp. n. is described from eastern North America. T. pilagens sp. n. is an obligate slave-making ant with two known hosts: T. longispinosus (Roger, 1863) and T. ambiguus (Emery, 1895). A differential diagnosis against Temnothorax duloticus (Wesson, 1937), the other dulotic congener from the Nearctic, is presented and a biological characteristics of the new species is given.

Evaluation of criteria for species delimitation of bagworm moths (Lepidoptera: Psychidae)

2014

Accurate identification of species is fundamental for biological research and necessary for species conservation. DNA bar- coding is particularly useful when identification using morphological characteristics is laborious and/or unreliable. However, bar- codes for species are dependent on the availability of reference sequences from correctly identified specimens. The traditional use of morphology to delimit the species boundaries of Finnish bagworm moths (Lepidoptera: Psychidae: Naryciinae: Dahliciini) is contro- versial because there is overlap in their morphological characteristics. In addition, there are no suitable molecular markers. We veri- fied the delimitation of seven out of eight…

Morphometric analysis of Tremadocian (earliest Ordovician) kirkocystid mitrates (Echinodermata, Stylophora) from the Taebaeksan Basin, Korea

2004

Abstract Abundant isolated remains of stylophoran echinoderms (cornutes and mitrates) are reported for the first time in the late Tremadocian (Asaphellus Zone) Tumugol Formation of Korea. Mitrate remains include numerous adorals of Kirkocystidae. Several new important anatomical features have been observed on these adorals, as an internal calcitic layer that is associated to s2 and possibly also to the palmar complex. This observation suggests that the palmar complex would be present not only in mitrocystitid mitrates, but also in peltocystitids. For the first time, several morphometric analyses have been undertaken based on isolated kirkocystid adorals, so as to explore the morphological d…

Revision of the genusTrogulus Latreille: the morphologically divergentTrogulus torosusspecies-group of the Balkan Peninsula (Opiliones: Dyspnoi: Trog…

2013

Within the species-rich European harvestman genus Trogulus Latreille, 1802, the Balkan Trogulus torosus species-group as defined by Schonhofer and Martens is revised. The group is remarkable because it includes the world's largest Opiliones species, Trogulus torosus Simon, 1885, and Trogulus ozimeci sp. nov. is the first member of the family showing obvious adaption to subterranean life. According to nuclear 28S and mitochondrial cytochrome b gene data, the T. torosus species-group and the Trogulus hirtus species-group form a monophyletic unit. Only the former is treated here as a paraphyletic group. Despite this paraphyly, the T. torosus species-group members share a number of morphologica…