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

Crustaceana ◽  
2020 ◽  
Vol 93 (3-5) ◽  
pp. 337-353
Author(s):  
Łukasz Sługocki

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.

2018 ◽  
Vol 8 (1) ◽  
pp. 222-232 ◽  
Author(s):  
R. V. Yakovlev ◽  
N. A. Shapoval ◽  
G. N. Kuftina ◽  
A. V. Kulak ◽  
S. V. Kovalev

The Proclossiana eunomia (Esper, 1799) complex is currently composed of the several subspecies distributed throughout Palaearсtic region and North America. Despite the fact that some of the taxa have differences in wing pattern and body size, previous assumptions on taxonomy not supported by molecular data. Therefore, the identity of certain populations of this complex has remained unclear and the taxonomic status of several recently described taxa is debated. Here, we provide insights into systematics of some Palaearctic members of this group using molecular approach, based on the analysis of the barcoding fragment of the COI gene taking into account known morphological differences.


2020 ◽  
Vol 29 (2) ◽  
pp. 278-283
Author(s):  
S.G. Ermilov

The oribatid mite subgenus Scheloribates (Topobates) Grandjean, 1958, is recorded from the Neotropical region for the first time. A new species of this subgenus is described from the leaf litter collected in Cayo Agua Island, Panama. Scheloribates (Topobates) panamaensis sp. nov. differs from its related species by the very large body size and presence of a strong ventrodistal process on the leg femora II–IV.


Author(s):  
Ricardo Wilches ◽  
William H Beluch ◽  
Ellen McConnell ◽  
Diethard Tautz ◽  
Yingguang Frank Chan

Abstract Most phenotypic traits in nature involve the collective action of many genes. Traits that evolve repeatedly are particularly useful for understanding how selection may act on changing trait values. In mice, large body size has evolved repeatedly on islands and under artificial selection in the laboratory. Identifying the loci and genes involved in this process may shed light on the evolution of complex, polygenic traits. Here, we have mapped the genetic basis of body size variation by making a genetic cross between mice from the Faroe Islands, which are among the largest and most distinctive natural populations of mice in the world, and a laboratory mouse strain selected for small body size, SM/J. Using this F2 intercross of 841 animals, we have identified 111 loci controlling various aspects of body size, weight and growth hormone levels. By comparing against other studies, including the use of a joint meta-analysis, we found that the loci involved in the evolution of large size in the Faroese mice were largely independent from those of a different island population or other laboratory strains. We hypothesize that colonization bottleneck, historical hybridization, or the redundancy between multiple loci have resulted in the Faroese mice achieving an outwardly similar phenotype through a distinct evolutionary path.


PLoS ONE ◽  
2009 ◽  
Vol 4 (1) ◽  
pp. e3876 ◽  
Author(s):  
C. Jaco Klok ◽  
Jon F. Harrison

Author(s):  
I. Boujenane ◽  
D. Petit

SummaryThe objective of this study was a morphological characterization of five Moroccan sheep breeds (Béni Guil, Boujaâd, D'man, Sardi and Timahdite) to assess between- and within-breed variability using multivariate analyses. Fourteen morphological measurements were collected on 876 adult animals of both sexes in 98 different flocks located in 22 geographic localities of five breeds. The multiple analysis of variance revealed that significant morphological differences existed between breeds. The overall proportion of total variance due to between-breed component was 28.3 percent. The factor analysis revealed three factors accounting for 50.1, 11.8 and 7.54 percent of total variance. The first factor had high loadings for variables relating to body size, whilst the second factor had high association with traits reflecting tail length and ear size. The third factor had high loadings for wool trait. The squared Mahalanobis distance between the five sheep breeds were highly significant (P< 0.001). The largest morphological divergence was shown between Béni Guil and Sardi breeds (23.5) and the smallest one was between Boujaâd and Sardi breeds (3.54). The discriminant functions clearly discriminated and assigned 94.4 percent of Béni Guil, 79.7 of Boujaâd, 88.5 percent of D'man, 86.7 of Sardi and 80.1 percent of Timahdite sheep into their breed of origin. Overall morphological differences observed within-breeds were due for 18.1 percent to geographic locality and for 20.7 percent to flock management. It was concluded that the information reported in this study will be the basis for the establishment of characterization and selection strategies for Moroccan sheep.


Author(s):  
И.А. Баландина ◽  
А.М. Некрасова ◽  
А.А. Баландин

Работа основана на морфологическом исследовании ампул маточных труб 130 рожавших женщин молодого и старческого возраста. Применены макрометрический, гистологический, иммуногистохимический и микрометрический методы исследования. Выявлены закономерности возрастной морфологической изменчивости ампулы маточной трубы, проявляющиеся в уменьшении параметров их длины, а также наружных диаметров в середине ампулы и в местах перехода перешейка в ампулу и ампулы в воронку от молодого возраста к старческому возрасту. Гистоархитектоника ампул маточных труб у женщин в старческом возрасте характеризуется уплощением эпителия слизистой оболочки, образующей обилие близлежащих утолщенных складок, формирующих неравномерное сужение просвета ампулы. Определяется истончение мышечной оболочки с разрастанием вместо нее соединительной ткани и скоплением адипоцитов в подсерозной основе. В старческом возрасте отмечается более выраженная экспрессия виментина, прослеживающаяся не только в эндотелии и субэндотелиальном слое кровеносных сосудов, включая капилляры, но и в отдельных фибробластах. Установлено, что особенности микрометрических характеристик ампул маточных труб заключаются в уменьшении внутреннего периметра эпителиальной выстилки и площади просвета, наряду с увеличением площади их стенки при срединном сечении, в старческом возрасте в сравнении с молодым. The work is based on a morphological study of ampoules of the fallopian tubes of 130 young and senile women who gave birth. Macrometric, histological, immunohistochemical and micrometric methods of investigation were applied. The regularities of age-related morphological variability of the fallopian tube ampoule are revealed, which are manifested in a decrease in the parameters of their length, as well as external diameters in the middle of the ampoule and at the places of transition of the isthmus into the ampoule and ampoule into the funnel from young age to old age. Histoarchitectonics of ampoules of the fallopian tubes in women in old age is characterized by flattening of the epithelium of the mucous membrane, which forms an abundance of nearby thickened folds that form an uneven narrowing of the lumen of the ampoule. The thinning of the muscle membrane is determined with the growth of connective tissue instead of it and the accumulation of adipocytes in the subserose base. In old age, there is a more pronounced expression of vimentin, which can be traced not only in the endothelium and subendothelial layer of blood vessels, including capillaries, but also in individual fibroblasts. It was found that the features of the micrometric characteristics of the fallopian tube ampoules consist in a decrease in the inner perimeter of the epithelial lining and the lumen area, along with an increase in the area of their wall at the median cross-section in old age compared with young age.


Author(s):  
Isain Zapata ◽  
M. Leanne Lilly ◽  
Meghan E. Herron ◽  
James A. Serpell ◽  
Carlos E. Alvarez

AbstractVery little is known about the etiology of personality and psychiatric disorders. Because the core neurobiology of many such traits is evolutionarily conserved, dogs present a powerful model. We previously reported genome scans of breed averages of ten traits related to fear, anxiety, aggression and social behavior in multiple cohorts of pedigree dogs. As a second phase of that discovery, here we tested the ability of markers at 13 of those loci to predict canine behavior in a community sample of 397 pedigree and mixed-breed dogs with individual-level genotype and phenotype data. We found support for all markers and loci. By including 122 dogs with veterinary behavioral diagnoses in our cohort, we were able to identify eight loci associated with those diagnoses. Logistic regression models showed subsets of those loci could predict behavioral diagnoses. We corroborated our previous findings that small body size is associated with many problem behaviors and large body size is associated with increased trainability. Children in the home were associated with anxiety traits; illness and other animals in the home with coprophagia; working-dog status with increased energy and separation-related problems; and competitive dogs with increased aggression directed at familiar dogs, but reduced fear directed at humans and unfamiliar dogs. Compared to other dogs, Pit Bull-type dogs were not defined by a set of our markers and were not more aggressive; but they were strongly associated with pulling on the leash. Using severity-threshold models, Pit Bull-type dogs showed reduced risk of owner-directed aggression (75th quantile) and increased risk of dog-directed fear (95th quantile). Our findings have broad utility, including for clinical and breeding purposes, but we caution that thorough understanding is necessary for their interpretation and use.


2019 ◽  
Vol 41 (3) ◽  
Author(s):  
Nguyen Ngoc Chau

Bakernema enormese sp. n., collected from rhizosphere of forest wood trees in Muong Phang, Dien Bien Province (north Vietnam) is described and illustrated. The new species is characterized by large body size and stylet. In general, this new species is close to two existing species of the same genus, B. inaequale and B. dauniense by cuticle structure in transparent membranous projections which appear in lateral view as spine-like structures on each annulus. These structure arranged into several rows along the body. In morphology, the new species differs from B. inaequale and B. dauniense  by body and stylet length, i.e. 609–842 µm and 143.5–150 µm vs. 391–578 µm and 59–74 µm for B. inaequale and vs. 391–461 µm and 65–74 µm for B. dauniense. In addition, new species can be distinguished from B. inaequale by the longer membranous projection, 8–12 vs. 6–10 µm and vagina shape, curved vs. sigmoid. From B. dauniense, the new species differs by the much longer membranous projection, 8–12 vs. 1.4–2.2 µm and less number annules between vulva and tail end (RV), 3–4 vs. 7.8 annules. The presence of Criconema (Nothocriconemella) graminicola Loof, Wouts & Yeates, in Vietnam with morphometrics, illustrators and remarks given.


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