Variability of mandible shape in the freshwater glacial relict Eurytemora lacustris (Poppe, 1887) (Copepoda, Calanoida, Temoridae)

Crustaceana ◽

10.1163/15685403-00003985 ◽

2020 ◽

Vol 93 (3-5) ◽

pp. 337-353

Author(s):

Łukasz Sługocki

Keyword(s):

Body Size ◽

Morphological Variability ◽

Large Body ◽

Dental Crowns ◽

Trophic Network ◽

Mandible Shape ◽

Food Conditions ◽

Glacial Relict ◽

Morphological Differences ◽

Mandibular Teeth

Abstract The mandibles of copepods are used to classify the feeding modes of certain species, because these appendages have specific shapes. The number, shape, location, and structure of the mandibular teeth are traits that are related to the feeding preferences of copepods. Therefore, the mandibles have been used as parameters in order to determine the role of the corresponding species in the trophic network. In this study, we aimed to determine the morphological variability of the mandible shape in a rare calanoid, Eurytemora lacustris (Poppe, 1887). The size of the mandibles of E. lacustris is closely related to its body size; however, considering the proportions of the width of the mandibles to that body size, young individuals have relatively larger mandibles. Despite the large body size of males, the females are characterized by larger mandibles than those of males. The teeth of males were found to be smaller, because of intensive abrasion. Moreover, the season and habitat affected the size of the mandibles and also the values of the edge index (EI). The food conditions in the studied lakes fluctuated within seasons, which led to changes in the shape of the dental crowns. Using this index (EI), E. lacustris was classified as an omnivorous species; however, the range of calculated values varied considerably. We note that the values of the EI decrease along with maturation, which suggests that with increase in age, the copepod becomes more herbivorous; however, this contradicts the paradigm that copepods become omnivorous during maturation. All those morphological differences, furthermore, indicate the high phenotypic plasticity of the species, which was found to be related to maturity, sex, phenology, and the environmental conditions of the habitat.

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Integration and Modularity of Quantitative Trait Locus Effects on Geometric Shape in the Mouse Mandible

Genetics ◽

10.1093/genetics/166.4.1909 ◽

2004 ◽

Vol 166 (4) ◽

pp. 1909-1921

Author(s):

Christian Peter Klingenberg ◽

Larry J Leamy ◽

James M Cheverud

Keyword(s):

Quantitative Trait ◽

Parametric Bootstrap ◽

Interval Mapping ◽

Procrustes Analysis ◽

Bootstrap Test ◽

Mandible Shape ◽

Trait Locus ◽

F2 Generation ◽

Analysis Interval ◽

Qtl Effects

Abstract The mouse mandible has long served as a model system for complex morphological structures. Here we use new methodology based on geometric morphometrics to test the hypothesis that the mandible consists of two main modules, the alveolar region and the ascending ramus, and that this modularity is reflected in the effects of quantitative trait loci (QTL). The shape of each mandible was analyzed by the positions of 16 morphological landmarks and these data were analyzed using Procrustes analysis. Interval mapping in the F2 generation from intercrosses of the LG/J and SM/J strains revealed 33 QTL affecting mandible shape. The QTL effects corresponded to a variety of shape changes, but ordination or a parametric bootstrap test of clustering did not reveal any distinct groups of QTL that would affect primarily one module or the other. The correlations of landmark positions between the two modules tended to be lower than the correlations between arbitrary subsets of landmarks, indicating that the modules were relatively independent of each other and confirming the hypothesized location of the boundary between them. While these results are in agreement with the hypothesis of modularity, they also underscore that modularity is a question of the relative degrees to which QTL contribute to different traits, rather than a question of discrete sets of QTL contributing to discrete sets of traits.

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Robust and Accurate Mandible Segmentation on Dental CBCT Scans Affected by Metal Artifacts Using a Prior Shape Model

Journal of Personalized Medicine ◽

10.3390/jpm11050364 ◽

2021 ◽

Vol 11 (5) ◽

pp. 364

Author(s):

Bingjiang Qiu ◽

Hylke van der van der Wel ◽

Joep Kraeima ◽

Haye Hendrik Glas ◽

Jiapan Guo ◽

...

Keyword(s):

State Of The Art ◽

Maxillofacial Surgery ◽

Cone Beam ◽

Oral And Maxillofacial Surgery ◽

Metal Artifacts ◽

Shape Model ◽

High Attenuation ◽

Mandible Shape ◽

Prior Shape ◽

Segmentation Models

Accurate mandible segmentation is significant in the field of maxillofacial surgery to guide clinical diagnosis and treatment and develop appropriate surgical plans. In particular, cone-beam computed tomography (CBCT) images with metal parts, such as those used in oral and maxillofacial surgery (OMFS), often have susceptibilities when metal artifacts are present such as weak and blurred boundaries caused by a high-attenuation material and a low radiation dose in image acquisition. To overcome this problem, this paper proposes a novel deep learning-based approach (SASeg) for automated mandible segmentation that perceives overall mandible anatomical knowledge. SASeg utilizes a prior shape feature extractor (PSFE) module based on a mean mandible shape, and recurrent connections maintain the continuity structure of the mandible. The effectiveness of the proposed network is substantiated on a dental CBCT dataset from orthodontic treatment containing 59 patients. The experiments show that the proposed SASeg can be easily used to improve the prediction accuracy in a dental CBCT dataset corrupted by metal artifacts. In addition, the experimental results on the PDDCA dataset demonstrate that, compared with the state-of-the-art mandible segmentation models, our proposed SASeg can achieve better segmentation performance.

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Mandible shape modeling using the second eigenfunction of the Laplace-Beltrami operator

10.1117/12.877537 ◽

2011 ◽

Cited By ~ 5

Author(s):

Seongho Seo ◽

Moo K. Chung ◽

Brian J. Whyms ◽

Houri K. Vorperian

Keyword(s):

Beltrami Operator ◽

Shape Modeling ◽

Mandible Shape

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Biometric Analysis of Cranial and Somatic Features in the Pannonian Root Vole

Animals ◽

10.3390/ani11020576 ◽

2021 ◽

Vol 11 (2) ◽

pp. 576

Author(s):

Ivan Baláž ◽

Filip Tulis ◽

Michal Ševčík

Keyword(s):

Body Weight ◽

Feeding Ecology ◽

Adult Population ◽

Tail Length ◽

Cranial Base ◽

Biometric Analysis ◽

Root Vole ◽

Average Value ◽

Hind Foot ◽

Glacial Relict

The Pannonian root vole Alexandromys oeconomus ssp. mehelyi represents a rare glacial relict, whose occurrence is nowadays bound to several areas in Europe. Four somatic and 25 craniological features were analysed, based on 355 measured specimens. Sex is a significant factor affecting the average value of all four somatic features, where all of them achieve higher values in males than in females. While body length and tail length were also affected by seasons, body weight and the length of the hind foot were stable features present across the seasons. In cranial features, the largest variability in the adult population is characterised by neurocranium breadth (LaN), total length of the cranial base (LB), and skull (LCr); whereas the smallest variability of the cranial dimensions is reflected in the values of the greatest palatal breadth (PS) and postorbital breadth (Io). Calculating the weight from cranial remains may be used to estimate the size of the prey and to determine vole biomass consumed by predators, such as raptors, highlighting the utility of studying feeding ecology.

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Population dynamics of the glacial relict amphipods in a subarctic lake: role of density‐dependent and density‐independent factors

Ecology and Evolution ◽

10.1002/ece3.8260 ◽

2021 ◽

Author(s):

Alexey A. Maximov

Keyword(s):

Population Dynamics ◽

Density Dependent ◽

Subarctic Lake ◽

Glacial Relict

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Survey and Distribution of Crustacea Malacostraca in Poland

Crustaceana ◽

10.1163/156854093x00540 ◽

1993 ◽

Vol 65 (2) ◽

pp. 176-191 ◽

Cited By ~ 12

Author(s):

Krzysztof Jaźdźewski ◽

Alicja Konopacka

Keyword(s):

Eriocheir Sinensis ◽

Inland Waters ◽

Asellus Aquaticus ◽

Astacus Leptodactylus ◽

Relict Species ◽

Mysis Relicta ◽

Orconectes Limosus ◽

Echinogammarus Ischnus ◽

Glacial Relict ◽

The Baltic

AbstractThe paper presents a survey of Polish malacostracan fauna. In two tables the distribution of freshwater and Baltic species is presented according to the regionalization of the country used in "Catalogus Faunae Poloniae". Figures present some interesting distributions of freshwater malacostracan taxa. Own studies as well as the review of ample literature aimed at the preparation of the successive issues of "Catalogus Faunae Poloniae" allowed to present this survey of 121 malacostracan taxa, viz., Bathynellacea - 1 species, Mysidacea - 9, Amphipoda - 50, Isopoda - 47, Tanaidacea - 1, Cumacea - 1, Euphausiacea - 1, Decapoda - 11. In inland waters 31 species and subspecies do occur (Batynellacea - 1, Mysidacea - 1, Amphipoda - 22, Isopoda - 2, Decapoda - 5). In brackish waters of the Baltic Sea and its lagoons- 54 species (Mysidacea - 8, Amphipoda - 24, Isopoda - 12, Tanaidacea - 1, Cumacea - 1, Euphausiacea - 1, Decapoda - 8). Bi-environmental species are Asellus aquaticus and Eriocheir sinensis. The land malacostracan fauna of Poland includes 4 amphipod and 34 isopod (oniscoid) taxa. The Polish malacostracan fauna is composed mainly of species that have invaded this region of Europe in the postglacial period, but the oldest, preglacial elements are subterranean amphipods (niphargids, Crangonyx) and Bathynella natans, occurring only in southern Poland. The earliest postglacial invaders of the Baltic and/or the northern lakes were glacial relict species like the Mysis relicta group, Pallasiola quadrispinosa, Monoporeia affinis and Saduria entomon. The Southern Baltic malacostracan fauna is dominated by Boreal and Arctic/(Subarctic)-boreal elements but one third of this fauna is Mediterranean-boreal or Lusitanian-boreal in origin. Inland waters were probably settled next by Gammarus lacustris, G. pulex, Synurella ambulans, Asellus aquaticus and Astacus astacus, then by later incomers, like Gammarus balcanicus. Canal constructions in the XVIIIth century helped the immigration of Ponto-Caspian elements: Corophium curvispinum and Echinogammarus ischnus. Intentionally introduced to Polish waters are Astacus leptodactylus, Orconectes limosus and Pacifastacus leniusculus; unintentionally brought along were Eriocheir sinensis and Rhithropanopeus harrisii tridentatus, as well as Talitroides alluaudi and Trichorhina tomentosa to some greenhouses.

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Great Plains Ladies’-tresses (Spiranthes magnicamporum) in the lower Great Lakes region and a new record for New York State

The Canadian Field-Naturalist ◽

10.22621/cfn.v129i2.1700 ◽

2015 ◽

Vol 129 (2) ◽

pp. 183

Author(s):

Daniel F. Brunton

Keyword(s):

New York ◽

Great Lakes ◽

Great Plains ◽

New Records ◽

New York State ◽

The United States ◽

Great Lakes Region ◽

Long Distance ◽

York State ◽

Glacial Relict

Six populations of Great Plains Ladies’-tresses (Spiranthes magnicamporum Sheviak) have recently been discovered in three locations east of the lower Great Lakes region of Canada and the United States. The possible occurrence of S. cernua × magnicamporum hybrids was detected at one New York site. These discoveries are from both natural alvar and disturbed meadow and shore sites. The new records suggest that S. magnicamporum occurs more widely than was suspected previously, its presence perhaps masked by its similarity to the common S. cernua (L.) Richard. Eastern occurrences may represent a combination of post-glacial relict populations, responses to climate change, and the results of long-distance dispersal events. These range extensions constitute the most easterly known populations of S. magnicamporum in North America. They also represent new records for New York State (including Jefferson and St. Lawrence Counties) and for the City of Ottawa in Ontario.

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