scholarly journals Morphometric assessment of pterosaur jaw disparity

2018 ◽  
Vol 5 (4) ◽  
pp. 172130 ◽  
Author(s):  
Charlie A. Navarro ◽  
Elizabeth Martin-Silverstone ◽  
Thomas L. Stubbs
Keyword(s):  
Morphological Diversity ◽  
Feeding Strategies ◽  
Size Distributions ◽  
Clear Trend ◽  
Geometric Morphometric ◽  
Lower Jaw ◽  
Successful Group ◽  
Outline Analysis ◽  
Key Driver ◽  
Morphometric Assessment

Pterosaurs were a successful group of Mesozoic flying reptiles. They were the first vertebrate group to achieve powered flight and varied enormously in morphology and ecology, occupying a variety of niches and developing specialized feeding strategies. Ecomorphological principles suggest this variation should be reflected by great morphological diversity in the lower jaw, given that the mandible served as the primary apparatus for prey acquisition. Here we present the first study of mandibular shape disparity in pterosaurs and aim to characterize major aspects of variation. We use a combination of geometric morphometric approaches, incorporating both outline analysis using elliptical Fourier analysis and semi-landmark approaches. Our results show that morphological convergence is prevalent and many pterosaurs, belonging to diverse dietary groups and subclades, overlap in morphospace and possessed relatively simple ‘rod-shaped’ jaws. There is no clear trend of size distributions in pterosaur mandibular morphospace, and larger forms are widely distributed. Additionally, there is limited functional signal within pterosaur lower jaw morphospace. Instead, the development of a large anterior ventral crest represents the major component of disparity. This suggests that a socio-sexual trait was a key driver for innovation in pterosaur lower jaw shape.

scholarly journals Split-footed lacewings declined over time: indications from the morphological diversity of their antlion-like larvae

PalZ ◽  
2021 ◽  
Author(s):  
Gideon T. Haug ◽  
Carolin Haug ◽  
Serita van der Wal ◽  
Patrick Müller ◽  
Joachim T. Haug
Keyword(s):  
Morphological Diversity ◽  
Single Specimen ◽  
Burmese Amber ◽  
The Past ◽  
The World ◽  
Poor Group ◽  
Outline Analysis ◽  
Loss Of Diversity ◽  
Over Time ◽  
Antlion Larvae

AbstractNymphidae, the group of split-footed lacewings, is a rather species-poor group. Split-footed lacewings nowadays are restricted to Australasia, while fossil forms are also known from other areas of the world, indicating that the group was more species-rich and therefore likely diverse in the past. Split-footed lacewings have rather distinct larvae, roughly resembling antlion larvae, but differing from the latter especially with regard to the mandibles. Antlion larvae usually have three prominent teeth on each mandible, while at least extant larvae of split-footed lacewings only have a single prominent tooth per mandible. Fossils interpreted as larvae of split-footed lacewings are well known from amber from Myanmar (ca. 100 myr; Burmese amber) and by a single specimen from Baltic amber (about 40 myr). We here report additional fossil specimens from Myanmar amber, expanding the known record of fossil forms from six depicted specimens to 15. For the extant fauna, we could compile 25 larvae. We compare the diversity of shape of extant and fossil larvae through time using an outline analysis (based on elliptic Fourier transformation) of the head. The results of this analysis indicate that the morphological diversity, or disparity, of split-footed lacewing larvae was higher in the past than it is today. With this type of analysis, we can show a loss of diversity over time, without the necessity to identify the fossil larvae down to a narrow taxonomical range. A similar pattern has already been recognised in silky lacewings, Psychopsidae. This might indicate a general loss of diversity of lacewing larvae.

Geometric morphometric analysis of different species of Cyprideis deriving from the Early Pleistocene record of Greece.

2021 ◽  
Author(s):  
Ypermachia Dimitriou ◽  
Penelope Papadopoulou ◽  
Maria Kolendrianou ◽  
Maria Tsoni ◽  
George Iliopoulos
Keyword(s):  
Endemic Species ◽  
Early Pleistocene ◽  
Geometric Morphometric ◽  
Representative Species ◽  
Lower Pleistocene ◽  
Close Relationship ◽  
Outline Analysis ◽  
Geometric Morphometric Analysis ◽  
The Right ◽  
Of Greece

<p>The genus Cyprideis is one of the most widespread ostracod representative of the Pleistocene brackish palaeoenvironments. Especially <em>Cyprideis torosa </em>is often found in great numbers and even in monospecific taphocoenoses and for this reason its study is very useful for palaeoenvironmental reconstructions.  The identification of different species of Cyprideis is often complicated and needs careful morphology inspection. This becomes even more difficult in the case of endemic species which present significant similarities with each other.  In this work, we have studied and analyzed several  Cyprideis species (<em>C.torosa, C. frydaci, C.dictyoti, C. pannonica, C. elisabeta, C. seminulum, C. heterostigma</em>) deriving from brackish palaeoenvironments of a Lower Pleistocene marl sequence in Sousaki Basin (Northeastern Corinth Graben, Greece). More specifically size measurements and geometric morphometrics (lateral valve outline of both right and left valves as well as females and males) were used in order to attest the similarities and dissimilarities between the different species and draw conclusions about their origin.  According to the valve outline and the multivariate analysis a close relationship between the valve shape of all Cyprideis species can be noticed. <em>C. torosa</em> is commonly grouped with <em>C. pannonica</em> except in the male right valve where the two species show some differences.  The endemic species <em>C. frydaci</em> and <em>C. dictyoti</em> can be identified by the differences in the right valve of the male and female respectively.  The other species could not be substantially differentiated using just the outline analysis which possibly denotes their common genetic origin.  The valve outline has proved to be a very useful character for recognizing the different species especially when the two valves of both females and males are considered. More analyses of representative species of Miocene and Pliocene Cyprideis are needed in order to establish their phylogenetic relationships and draw conclusions about their common ancestor.</p>

scholarly journals Morphological diversity in tenrecs (Afrosoricida, Tenrecidae): comparing tenrec skull diversity to their closest relatives

2015 ◽  
Author(s):  
Sive Finlay ◽  
Natalie Cooper
Keyword(s):  
Quantitative Analysis ◽  
Quantitative Methods ◽  
Morphological Diversity ◽  
Lateral View ◽  
Ecological Niches ◽  
Diverse Group ◽  
Geometric Morphometric ◽  
Skull Shape ◽  
Morphometric Analyses ◽  
The Family

Morphological diversity is often studied qualitatively. However, to truly understand the evolution of exceptional diversity, it is important to take a quantitative approach instead of relying on subjective, qualitative assessments. Here, we present a quantitative analysis of morphological diversity in a Family of small mammals, the tenrecs (Afrosoricida, Tenrecidae). Tenrecs are often cited as an example of an exceptionally morphologically diverse group. However, this assumption has not been tested quantitatively. We use geometric morphometric analyses of skull shape to test whether tenrecs are more morphologically diverse than their closest relatives, the golden moles (Afrosoricida, Chrysochloridae). Tenrecs occupy a wider range of ecological niches than golden moles so we predict that they will be more morphologically diverse. Contrary to our expectations, We find that tenrec skulls are only more morphologically diverse than golden moles when measured in lateral view. Furthermore, similarities among the species-rich Microgale tenrec Genus appear to mask higher morphological diversity in the rest of the Family. These results reveal new insights into the morphological diversity of tenrecs and highlight the importance of using quantitative methods to test qualitative assumptions about patterns of morphological diversity.

scholarly journals Morphological diversity of the stone crayfish − traditional and geometric morphometric approach

2019 ◽  
pp. 1 ◽  
Author(s):  
Leona Lovrenčić ◽  
Vjera Pavić ◽  
Stefan Majnarić ◽  
Lucija Abramović ◽  
Mišel Jelić ◽  
...  
Keyword(s):  
Morphological Variability ◽  
Morphological Characteristics ◽  
Morphological Diversity ◽  
Dorsal Side ◽  
Small Scale ◽  
Geometric Morphometric ◽  
Discriminant Analyses ◽  
Stone Crayfish ◽  
Multivariate Discriminant ◽  
First Time

Austropotamobius torrentium is one of four native European crayfish species inhabiting Croatian freshwaters. Existence of eight divergent monophyletic mtDNA phylogroups was described within A. torrentium; six of them are distributed in Croatia, with the highest genetic diversity established in its northern-central Dinaric region. Recent small-scale study of the stone crayfish morphological variability indicated significant differences among different phylogroups. In the present study larger sample size, covering populations from five phylogroups, was analysed with the aim of determining whether there are morphological characteristics that reliably separate stone crayfish from different phylogroups. Aiming this, 245 stone crayfish were analysed through traditional (TM) and, for the first time, geometric morphometric (GM) analyses. Multivariate discriminant analyses included 24 TM characteristics per crayfish, while GM comprised analyses of 22 landmarks on the dorsal side of cephalon. Both methods revealed congruent results, and significant differences among phylogroups in analysed features were obtained, with the cephalon shape contributing the most to crayfish discrimination. Research confirmed that both approaches, combined with statistical methods, are useful in distinguishing and separating crayfish phylogroups. Findings of present study are compatible with the previous molecular findings; stone crayfish present several distinct evolutionary lineages whose species status are currently undefined and require urgent clarification.

scholarly journals Optimal fishing samplers to reveal the morphological structure of a fish assemblage in a subtropical tidal flat

2019 ◽  
Vol 17 (1) ◽  
Author(s):  
Carolina C. Siliprandi ◽  
Víctor M. Tuset ◽  
Antoni Lombarte ◽  
Marc Farré ◽  
Carmen L. D. B. Rossi-Wongtschowski
Keyword(s):  
Tidal Flat ◽  
Fish Assemblage ◽  
Fish Assemblages ◽  
Morphological Variability ◽  
Morphological Structure ◽  
Morphological Diversity ◽  
Morphological Characters ◽  
Otter Trawl ◽  
Brazilian Coast ◽  
Geometric Morphometric

ABSTRACT Morphological characters of species are essential for assessing the functional structure of a fish assemblage, since differences between them, for example in body shape, are related to many functional and ecological traits (e.g., swimming, search for food, striking and capturing prey, evading predators, spawning). Globally, tidal flats are relevant to fish assemblages by offering feeding, refuge, and reproduction grounds. To analyze the morphofunctional structure of the fish assemblage from a tidal flat on the Brazilian coast, we conducted standardized sampling using nine different fishing gears. The geometric morphometric method was applied to describe the fish shapes and verify the morphological structure of the assemblage. Here, we present the influence/susceptibility of each gear type on the morphological diversity of the fish assemblage. The results indicated that beach seine, otter trawl, marginal encircling gillnet, and fish traps, together, were the most effective gears to represent the maximum morphological variability of fish inhabiting that tidal flat. Moreover, the assemblage showed high morphological redundancy considered as a resistance of the ecosystem for avoiding functional diversity loss, emphasizing the importance of complementary gear use when determining fish assemblages in a conservation context.

A geometric-morphometric assessment of three-dimensional models of experimental cut-marks using flint and quartzite flakes and handaxes

2019 ◽  
Vol 517 ◽  
pp. 45-54 ◽  
Author(s):  
Gonzalo José Linares-Matás ◽  
José Yravedra ◽  
Miguel Ángel Maté-González ◽  
Lloyd A. Courtenay ◽  
Julia Aramendi ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Geometric Morphometric ◽  
Cut Marks ◽  
Dimensional Models ◽  
Three Dimensional Models ◽  
Morphometric Assessment

Functional diversity in biters: the evolutionary morphology of the oral jaw system in pacus, piranhas and relatives (Teleostei: Serrasalmidae)

2019 ◽  
Vol 127 (4) ◽  
pp. 722-741 ◽  
Author(s):  
Alessia Huby ◽  
Aurélien Lowie ◽  
Anthony Herrel ◽  
Régis Vigouroux ◽  
Bruno Frédérich ◽  
...  
Keyword(s):  
Morphological Traits ◽  
Morphological Diversity ◽  
Evolutionary Morphology ◽  
Trophic Specialization ◽  
Jaw Muscles ◽  
Lower Jaw ◽  
Carnivorous Species ◽  
Herbivorous Species ◽  
Fish Group

Abstract Serrasalmid fishes form a highly specialized group of biters that show a large trophic diversity, ranging from pacus able to crush seeds to piranhas capable of cutting flesh. Their oral jaw system has been hypothesized to be forceful, but variation in bite performance and morphology with respect to diet has not previously been investigated. We tested whether herbivorous species have higher bite forces, larger jaw muscles and more robust jaws than carnivorous species. We measured in vivo and theoretical bite forces in 27 serrasalmid species. We compared the size of the adductor mandibulae muscle, the jaw mechanical advantages, the type of jaw occlusion, and the size and shape of the lower jaw. We also examined the association between bite performance and functional morphological traits of the oral jaw system. Contrary to our predictions, carnivorous piranhas deliver stronger bites than their herbivorous counterparts. The size of the adductor mandibulae muscle varies with bite force and muscles are larger in carnivorous species. Our study highlights an underestimated level of functional morphological diversity in a fish group of exclusive biters. We provide evidence that the trophic specialization towards carnivory in piranhas results from changes in the configuration of the adductor mandibulae muscle and the lower jaw shape, which have major effects on bite performance and bite strategy.

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