scholarly journals Variation in the pelvic and pectoral girdles of Australian Oligo–Miocene mekosuchine crocodiles with implications for locomotion and habitus

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e3501 ◽  
Author(s):  
Michael D. Stein ◽  
Adam Yates ◽  
Suzanne J. Hand ◽  
Michael Archer
Keyword(s):  
Morphological Variation ◽  
Middle Miocene ◽  
Iliac Crest ◽  
Morphological Changes ◽  
Parsimony Analysis ◽  
Crown Group ◽  
Hunting Strategies ◽  
Pelvic Limb ◽  
Relationship Of ◽  
Cranial Shape

Australian Oligo–Miocene mekosuchines (Crocodylia; Crocodyloidea) display wide diversity in cranial shape and inferred hunting strategies. Terrestrial habitus has been inferred for these distinctive predators. A direct morphological signal for locomotion can be expected in the postcrania, particularly the pelvic and pectoral girdles. Here we describe fossil materials of the girdles, which chart their morphological variation in the subfamily from Eocene through to Middle Miocene. Over this period, both girdles undergo significant morphological changes. Notably, an enclosed, ventrally orientated acetabulum in the ilium is developed in one lineage. This recapitulates the erect parasagittal configuration of the pelvic limb seen in many Mesozoic crocodylomorph lineages, suggesting consistent use of erect high-walking in these mekosuchines. Other pelves from the same Oligo–Miocene deposits display morphology closer to modern crocodilians, suggesting a partitioning of locomotory strategy among sympatric mekosuchines. Plesiomorphic and derived pelvic girdles are distinguishable by parsimony analysis, and the earliest examples of the mekosuchine pelvis more closely resemble gavialids and alligatorids while latter forms converge on crown group crocodylids in the morphology of the iliac crest. This suggests that a revaluation of the base relationship of Mekosuchinae within Eusuchia is necessary.

scholarly journals Sublime recapitulation: Evolution of the appendicular skeleton of Australian Mekosuchinae crocodiles.

2017 ◽  
Author(s):  
Michael D Stein
Keyword(s):  
Finite Element ◽  
Morphological Variation ◽  
Middle Miocene ◽  
Pelvic Girdle ◽  
Appendicular Skeleton ◽  
Finite Element Analyses ◽  
Stress Variation ◽  
Geometric Morphometric ◽  
Collaborative Project ◽  
Hunting Strategies

Australian mekosuchines (Crocodylia; Crocodyloidea) with their wide diversity of cranial shape and inferred hunting strategies present a fascinating window into the diversification processes of crocodilians. This includes lingering questions as to the extent of any terrestrial habitus. A direct morphological signal for locomotion can be expected in the postcrania, particularly the girdles and the limbs of the appendicular skeleton. After a lengthy survey, enough materials of the pelvic girdle are available to chart morphological variation in the subfamily from Eocene through to middle Miocene. Over this period, the pelvis has undergone a vigorous morphological radiation. An enclosed, ventrally oriented acetabulum in the ilium developed in one lineage that apparently recapitulates the pillar-erect configuration of the pelvic girdle seen in many Mesozoic crocodilian lineages, suggesting consistent use of erect high-walk in these mekosuchines. Other pelves from Oligo–Miocene deposits display morphology closer to modern crocodilians despite clearly representing derived forms themselves, indicating a partition of locomotory strategy in the fauna during the Oligo–Miocene. While materials of hindlimb remain frustratingly lacking in light of this discovery, enough materials of forelimb humeri have been uncovered to chart the morphological variation in the subfamily from Eocene through to Pleistocene, corroborating what is seen in the pelvic girdle. As such, a collaborative project has been started that aims to quantitatively asses shape and stress variation in the mekosuchine forelimb using geometric morphometric and finite element analyses.

scholarly journals Sublime recapitulation: Evolution of the appendicular skeleton of Australian Mekosuchinae crocodiles.

2017 ◽  
Author(s):  
Michael D Stein
Keyword(s):  
Finite Element ◽  
Morphological Variation ◽  
Middle Miocene ◽  
Pelvic Girdle ◽  
Appendicular Skeleton ◽  
Finite Element Analyses ◽  
Stress Variation ◽  
Geometric Morphometric ◽  
Collaborative Project ◽  
Hunting Strategies

Australian mekosuchines (Crocodylia; Crocodyloidea) with their wide diversity of cranial shape and inferred hunting strategies present a fascinating window into the diversification processes of crocodilians. This includes lingering questions as to the extent of any terrestrial habitus. A direct morphological signal for locomotion can be expected in the postcrania, particularly the girdles and the limbs of the appendicular skeleton. After a lengthy survey, enough materials of the pelvic girdle are available to chart morphological variation in the subfamily from Eocene through to middle Miocene. Over this period, the pelvis has undergone a vigorous morphological radiation. An enclosed, ventrally oriented acetabulum in the ilium developed in one lineage that apparently recapitulates the pillar-erect configuration of the pelvic girdle seen in many Mesozoic crocodilian lineages, suggesting consistent use of erect high-walk in these mekosuchines. Other pelves from Oligo–Miocene deposits display morphology closer to modern crocodilians despite clearly representing derived forms themselves, indicating a partition of locomotory strategy in the fauna during the Oligo–Miocene. While materials of hindlimb remain frustratingly lacking in light of this discovery, enough materials of forelimb humeri have been uncovered to chart the morphological variation in the subfamily from Eocene through to Pleistocene, corroborating what is seen in the pelvic girdle. As such, a collaborative project has been started that aims to quantitatively asses shape and stress variation in the mekosuchine forelimb using geometric morphometric and finite element analyses.

scholarly journals Rule Based Morphological Variation Removable Stemming Algorithm

2019 ◽  
Vol 8 (4) ◽  
pp. 1809-1814
Keyword(s):  
Feature Selection ◽  
Sentiment Analysis ◽  
Morphological Variation ◽  
Morphological Changes ◽  
The Internet ◽  
Rule Based ◽  
The People ◽  
Stop Word ◽  
Preprocessing Technique ◽  
Better Than

Sentiment analysis is a technique to analyze the people opinion, attitude, sentiment and emotion towards any particular object. Sentiment analysis has the following steps to predict the opinion of a review sentences. The steps are preprocessing, feature selection, classification and sentiment prediction. Preprocessing is the main important step and it consists of many techniques. They are Stop word Removal, punctuation removal, conversion of numbers to number names. Stemming is another important preprocessing technique which is used to transform the words in text into their grammatical root form and is mainly used to improve the retrieval of the information from the internet. It is applied mainly to get strengthen the retrieval of the information. Many morphological languages have immense amount of morphological deviation in the words. It triggered vast challenges. Many algorithms exist with different techniques and has several drawbacks. The aim of this paper is to propose a rule based stemmer that is a truncating stemmer. The new stemming mechanism in this paper has brought about many morphological changes. The new rule based morphological variation removable stemming algorithm is better than the existing other algorithms such as New Porter, Paice/Lovins and Lancaster stemming algorithm

scholarly journals Relationship of arctic fox (Alopex lagopus L.) sperm morphology with age of males, sperm concentration, ejaculate volume and acrosin activity

2018 ◽  
Vol 18 (3) ◽  
pp. 741-752 ◽  
Author(s):  
Karolina Stasiak ◽  
Stanisław Kondracki ◽  
Maria Iwanina
Keyword(s):  
Sperm Morphology ◽  
Semen Quality ◽  
Morphological Changes ◽  
Sperm Concentration ◽  
Arctic Fox ◽  
Young Males ◽  
Arctic Foxes ◽  
Relationship Of ◽  
Acrosin Activity ◽  
Sperm Acrosome

Abstract The aim of the study was to determine the relationship of sperm morphology with age of males, ejaculate concentration and volume, as well as with acrosin activity determined in sperm acrosome extracts. The study used manually collected ejaculates from 9 male arctic foxes, including 6 young males aged one year and 3 older males (between 3 and 5 years of age). All of the 39 ejaculates used in the study were classified as normal based on motility exceeding 70%. The ejaculates collected from the foxes were evaluated for volume, sperm concentration and frequency of morphological changes including primary and secondary defects. The spermiograms of the male arctic foxes were classified according to a six-grade subjective scale. In addition, acrosin activity was determined in the sperm acrosome extracts. The data were analysed using the criteria of male age, sperm concentration, ejaculate volume, and acrosin activity. The morphology of arctic fox spermatozoa was dependent on the age of the male. A greater number of morphologically altered spermatozoa tended to occur in the ejaculates of young foxes, which were in their first breeding season. In addition, statistical analysis revealed positive relationships between the frequency of morphological changes in sperm and their ejaculate concentration. In contrast, there were no significant correlations between the percentages of morphologically changed spermatozoa and the ejaculate volume and the content of acrosin, which is an indicator of acrosomal integrity. Semen quality is dependent on the number of sperm in ejaculate with morphological defects which prevent oocyte fertilization. Therefore, morphological assessment of semen, which covers both the number and type of morphological changes, is highly useful when selecting appropriate males for reproduction.

Morphology, anatomy, phylogenetics and distribution of fossil and extant Trochodendraceae in the Northern Hemisphere

2020 ◽  
Author(s):  
Steven R Manchester ◽  
Zlatko Kvaček ◽  
Walter S Judd
Keyword(s):  
Northern Hemisphere ◽  
Late Cretaceous ◽  
Morphological Characters ◽  
Basal Part ◽  
Parsimony Analysis ◽  
Crown Group ◽  
Modern Species ◽  
The Family ◽  
New Material ◽  
Fossil Fruit

Abstract We present the oldest known occurrences of crown-group Trochodendraceae based on new material from the Palaeocene of Wyoming, USA. Two genera are recognized, Trochodendron and Eotrochion gen. nov. The fossil fruit of Trochodendron infernense sp. nov. is represented by a pedicellate, apically dehiscent capsular fruit composed of nine follicle-like units, each bearing a persistent convex style. The basal part is ornamented with numerous raised stamen scars. From the same deposits, Eotrochion is represented by infructescences, fruits and associated leaves. The infructescences are racemes of numerous apically dehiscent capsules, each with c. 14–16 styles, each with an underlying nectary and receptacles lacking stamen scars, but possessing a prominent perianth scar. A phylogenetic assessment of the modern species, plus representatives of four extinct genera of fossil Trochodendraceae based on available morphological characters, yields a favoured topology of Trochodendron(Eotrochion(Concavistylon kvacekii(C. wehrii (Pentacentron, Tetracentron)))). A parsimony analysis of currently available characters indicates that C. wehrii renders Concavistylon non-monophyletic. Accordingly, we transfer it to Paraconcavistylon gen. nov., characterized by pendent, rather than erect infructescences. We also reconsider the extinct Nordenskioeldia (Late Cretaceous to Miocene), the prior placement of which in Trochodendraceae has been challenged, and we consider it to fall outside the crown group of the family.

scholarly journals Heterochronic Shifts Mediate Ecomorphological Convergence in Skull Shape of Microcephalic Sea Snakes

2019 ◽  
Vol 59 (3) ◽  
pp. 616-624 ◽  
Author(s):  
Emma Sherratt ◽  
Kate L Sanders ◽  
Amy Watson ◽  
Mark N Hutchinson ◽  
Michael S Y Lee ◽  
...  
Keyword(s):  
Morphological Changes ◽  
Shape Variation ◽  
Micro Computed Tomography ◽  
Trophic Specialization ◽  
Evolutionary Patterns ◽  
Dietary Specialization ◽  
Geometric Morphometric ◽  
Sea Snakes ◽  
Morphometric Methods ◽  
Cranial Shape

Abstract Morphological variation among the viviparous sea snakes (Hydrophiinae), a clade of fully aquatic elapid snakes, includes an extreme “microcephalic” ecomorph that has a very small head atop a narrow forebody, while the hind body is much thicker (up to three times the forebody girth). Previous research has demonstrated that this morphology has evolved at least nine times as a consequence of dietary specialization on burrowing eels, and has also examined morphological changes to the vertebral column underlying this body shape. The question addressed in this study is what happens to the skull during this extreme evolutionary change? Here we use X-ray micro-computed tomography and geometric morphometric methods to characterize cranial shape variation in 30 species of sea snakes. We investigate ontogenetic and evolutionary patterns of cranial shape diversity to understand whether cranial shape is predicted by dietary specialization, and examine whether cranial shape of microcephalic species may be a result of heterochronic processes. We show that the diminutive cranial size of microcephalic species has a convergent shape that is correlated with trophic specialization to burrowing prey. Furthermore, their cranial shape is predictable for their size and very similar to that of juvenile individuals of closely related but non-microcephalic sea snakes. Our findings suggest that heterochronic changes (resulting in pedomorphosis) have driven cranial shape convergence in response to dietary specializations in sea snakes.

scholarly journals Comparisons of Waist Circumference Measurements at Five Different Anatomical Sites in Chinese Children

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Chaoran Yang ◽  
Lin Wang
Keyword(s):  
Waist Circumference ◽  
Body Fat ◽  
Fat Mass ◽  
Iliac Crest ◽  
Chinese Children ◽  
Body Fat Mass ◽  
Strongly Correlated ◽  
Fat Percentage ◽  
Relationship Of ◽  
The Relationship

This study compared the waist circumference (WC) measurements of Chinese children at different sites to determine the relationship between WC measurements and body fat. WC was measured at five sites in 255 subjects aged 9–19 years: immediately below the lowest rib (WC1), at the narrowest waist (WC2), the midpoint between the lowest rib and the iliac crest (WC3), 1 cm above the umbilicus (WC4), and immediately above the iliac crest (WC5). Body fat mass (FM), body fat percentage (% BF), body fat mass in the trunk (FM in the trunk), and fat percentage in the trunk (% BF in the trunk) were determined by dual-energy X-ray absorptiometry. The WCs were then compared through ANOVA with repeated measurement. The relationship of WC of each site with FM, % BF, FM in the trunk, and % BF in the trunk was examined through partial correlation. The WCs exhibited the following pattern: WC2 < WC1 < WC3 < WC4 < WC5 (p<0.001) in males and WC2 < WC1 < WC4, WC3 < WC5 (p<0.001) in females. The measured WCs were strongly correlated with FM, % BF, FM in the trunk, and % BF in the trunk. The WC measurements at five commonly used sites among Chinese children are different from one another. Results indicate that standardizing the anatomic point for the WC measurements is necessary.

Distribution, morphological variation, and systematic relationship of Pholis laeta and P. ornata (Pisces: Pholididae) with a description of the related form P. nea n. sp.

1984 ◽  
Vol 62 (2) ◽  
pp. 291-305 ◽  
Author(s):  
Alex E. Peden ◽  
Grant W. Hughes
Keyword(s):  
British Columbia ◽  
New Species ◽  
Morphological Variation ◽  
North Pacific ◽  
Commander Islands ◽  
Systematic Relationship ◽  
The North ◽  
Pacific Waters ◽  
Relationship Of ◽  
Northern Japan

Although Pholis laeta and P. ornata are generally recorded in the literature as being distributed between California and Asiatic waters, we could not find verifiable specimens or records of P. ornata from Alaskan or western Pacific waters. A population in northern Japan is distinguishable and described here as the new species Pholis nea. Differences between P. laeta and P. ornata are too small for recognition of separate genera. Pholis laeta, which ranges from California to at least the Commander Islands, U.S.S.R.; exhibits clinal pigmentary differences between British Columbia and southern Oregon. Morphologically, P. ornata is relatively uniform between populations except for the north–south cline of median counts (= dorsal and anal rays plus vertebrae) typical of many North Pacific fishes.

scholarly journals Evolutionary morphology of the rabbit skull

PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e2453 ◽  
Author(s):  
Brian Kraatz ◽  
Emma Sherratt
Keyword(s):  
Small Proportion ◽  
Phylogenetic Signal ◽  
Morphological Data ◽  
Shape Variation ◽  
Evolutionary Morphology ◽  
Crown Group ◽  
Size Change ◽  
Generalist Species ◽  
Facial Region ◽  
Cranial Shape

The skull of leporids (rabbits and hares) is highly transformed, typified by pronounced arching of the dorsal skull and ventral flexion of the facial region (i.e., facial tilt). Previous studies show that locomotor behavior influences aspects of cranial shape in leporids, and here we use an extensive 3D geometric morphometrics dataset to further explore what influences leporid cranial diversity. Facial tilt angle, a trait that strongly correlates with locomotor mode, significantly predicts the cranial shape variation captured by the primary axis of cranial shape space, and describes a small proportion (13.2%) of overall cranial shape variation in the clade. However, locomotor mode does not correlate with overall cranial shape variation in the clade, because there are two district morphologies of generalist species, and saltators and cursorial species have similar morphologies. Cranial shape changes due to phyletic size change (evolutionary allometry) also describes a small proportion (12.5%) of cranial shape variation in the clade, but this is largely driven by the smallest living leporid, the pygmy rabbit (Brachylagus idahoensis). By integrating phylogenetic history with our geometric morphometric data, we show that the leporid cranium exhibits weak phylogenetic signal and substantial homoplasy. Though these results make it difficult to reconstruct what the ‘ancestral’ leporid skull looked like, the fossil records suggest that dorsal arching and facial tilt could have occurred before the origin of the crown group. Lastly, our study highlights the diversity of cranial variation in crown leporids, and highlights a need for additional phylogenetic work that includes stem (fossil) leporids and includes morphological data that captures the transformed morphology of rabbits and hares.

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