Ontogenetic Studies Research Articles

Brazilian Bothrops diporus, in fact a lineage of Bothrops pubescens: Mitogenomic, venomic and ontogenetic studies

Brazilian Bothrops diporus, in fact a lineage of Bothrops pubescens: Mitogenomic, venomic and ontogenetic studies

Suggested mechanisms underlying pollen wall development in Ambrosia trifida (Asteraceae: Heliantheae).

By a detailed ontogenetic study of Ambrosia trifida pollen, tracing each stage of development with TEM, we aim to understand the establishment of the pollen wall and to unravel the mechanisms underlying sporoderm development. The main steps of exine ontogeny in Ambrosia trifida, observed in the microspore periplasmic space, are as follows: spherical units, gradually transforming into columns, then to rod-like units; the appearance of the initial reticulate tectum; growth of columellae under the tectum and initial sporopollenin accumulation on them; the appearance of the endexine lamellae, first in fragments, then in long laminae; the cessation of the glycocalyx growth and its detachment from the plasma membrane, resulting in the appearance of gaps; massive accumulation of sporopollenin on the tectum, columellae, and endexine, and the appearance of the foot layer at the young post-tetrad stage, accompanied by establishment of caveae in sites of the former gaps; and final massive sporopollenin accumulation. This sequence of developmental events in all probability corresponds to the sequence of self-assembling micellar mesophases. This gives (together with earlier findings and experimental modeling of exine) strong evidence that the genome and self-assembly share control of exine formation. In this sense, self-assembly itself can be seen as an inherent mechanism of evolution.

Ontogeny of the Massospondylus labyrinth: implications for locomotory shifts in a basal sauropodomorph dinosaur

AbstractOntogeny is a vital aspect of life history sometimes overlooked in palaeontological studies. However, the changing geometry of anatomical structures during growth can be informative regarding ecological and functional reconstructions. The inner ear, or labyrinth, is an ideal ontogenetic study system because it has a strong functional signal in its morphology that is linked to locomotor mode. Yet almost nothing is known about labyrinth development in dinosaurs. We quantified labyrinth scale and geometry through ontogeny in the Early Jurassic dinosaur Massospondylus carinatus, which has an exceptional fossil record and is hypothesized to have undergone a gait change, from quadrupedal juvenile to bipedal adult. To test whether this putative locomotor shift is reflected in labyrinth morphology, computed microtomography (μCT) and propagation phase‐contrast synchrotron radiation microtomography (PPC‐SRμCT) were used to obtain labyrinths from eight specimens, ranging from near‐hatchling to adult. Labyrinths grow substantially but scale with slight negative allometry compared to skull length throughout ontogeny, the first time this has been documented in dinosaurs. Geometric morphometric analysis of the labyrinth using a sliding semilandmark approach shows some morphological change through ontogeny, but little evidence supporting a locomotor shift. These results have implications for our understanding of sauropodomorph development and provide a better understanding of dinosaur locomotory evolution.

A reappraisal of the genus Tethyrhynchia Logan, 1994 (Rhynchonellida, Brachiopoda): a conflict between phylogenies obtained from morphological characters and molecular data.

The genus Tethyrhynchia Logan in Logan Zibrowius, 1994 is revised on the basis of different methods of analysis including SEM observations, detailed ontogenetic study of the crural development, transverse serial sections, and shell microstructure. Some morphological characters cited in the original diagnosis are analysed and contested by the ontogenetic results. The type of crura of Tethyrhynchia, often placed in the arcual group, appears to be of the raducal group, instead. Paedomorphosis and heterochronic development offer the possibility of opening a dialogue between morphological and phylogenetic approaches to classification of rhynchonellide brachiopods.

Haustório, haustor, apressório, extensor:

A forma de vida parasitária em plantas está associada à formação de um órgão que pode ser genericamente denominado haustório, responsável pela conexão entre parasita e hospedeira. A grande diversidade de espécies parasitas - cerca de 1% das angiospermas viventes - somada à diversidade de potenciais hospedeiras, resulta numa multiplicidade de estruturas, tecidos e tipos celulares peculiares dessas interações. Entretanto, é frequente a observação de que toda esta variedade morfoanatômica seja abordada com o uso de poucos termos comuns e, até mesmo, com sinônimos, mas também com uso ambíguo e em estruturas de homologia dúbia ou não comprovada ontogeneticamente. O uso de publicações originalmente em outras línguas que o português (i.e. inglês, principalmente; espanhol; francês; italiano; alemão), com traduções literais, falsos cognatos e outras influências da linguística também promoveram confusões. De modo a promover uma utilização mais clara e precisa, além de realizar um resgate histórico das acepções originais dos termos, foi realizada uma compilação e reestruturação de termos do modo como vêm sendo abordados, de forma a promover um melhor entendimento da nomenclatura utilizada. Adicionalmente, estudos anatômicos e ontogenéticos têm sido realizados e confrontados com a literatura, e então resignificados sob uma perspectiva filogenética. Com base em nossos resultados e reflexões, apresentamos um glossário ilustrado e referenciado, com o qual sugerimos uma padronização de termos mais adequados na descrição da interface parasita-hospedeira de diversas famílias em língua portuguesa.

Solea senegalensis skeletal ossification and gene expression patterns during metamorphosis: New clues on the onset of skeletal deformities during larval to juvenile transition

Farmed Senegalese sole (Solea senegalensis) still show a high incidence of vertebral anomalies that limit its intensive production and hamper its economic profitability. A great effort towards understanding how fish species develops and grows in captivity has been undertaken in the last decade, with particular emphasis to how different biotic and abiotic factors affect its skeletal development. Although some work has been performed on its skeletal development and expression patterns of key genes in developmental signaling pathways, a detailed description of the above-mentioned processes is still lacking. Here, the progression of skeletal development of cranial, appendicular and axial skeleton has been described through the implementation of an acid free double staining protocol; while the gene expression pattern of vitamin A (VA) and thyroid hormones (THs) signaling pathways were assessed through quantitative PCR (qPCR) during larval fish development under a standard larval rearing protocol and in Senegalese sole larvae fed with increased dietary VA levels (8-fold increase) during the Artemia feeding phase (from 6 to 27 dph). The ontogenetic study allowed us to identify the onset and follow-up the development of most skeletal structures in this fish species, and to gather some insights on the potential onset of deformities originated at the larval to juvenile transition affecting Senegalese sole rearing. The pro-metamorphosis stage is when the caudal fin vertebrae are formed, where the most common skeletal deformities are found in Senegalese sole. A highly coordinated expression of VA- and TH-related genes has been revealed during larval to juvenile transition, while a comparative gene expression analysis in larvae fed control and high dietary VA content identified the specific timing of VA and THs signaling disruption through which VA and THs directly or indirectly might increase the incidence of skeletal deformities in this species. The present research work represents an important step forward towards the proper identification of the onset of some skeletal deformities and urge the investigation of nutritional and rearing conditions during the switch of larval behavior - from pelagic to benthonic - in order to overcome them in this important species for southwestern European aquaculture.

Why Kinesthesia, Tactility and Affectivity Matter: Critical and Constructive Perspectives

This article offers critical and constructive perspectives essential to understanding living bodies, and, in effect, to showing that kinesthesia, tactility and affectivity matter because they are central to animate life. Critical perspectives focus on practices that distance us from the lived realities of animate nature, on insights into those realities, and on ways in which language is intimately related to those realities. Constructive perspectives focus on ontogenetic studies that empirically testify to our being animate organisms from the start. The studies validate Husserl’s insight into the developmental progression from ‘I move’ to ‘I do’ to ‘I can’. On the basis of these perspectives, concluding observations focus on the mutual validation of empirical and phenomenological research, on the distinction between movement and objects in motion, on the distinction between perceiving and feeling one’s body, and on the distinction between having a body and being a body.

Comparative description and ossification patterns of Dendropsophus labialis (Peters, 1863) and Scinax ruber (Laurenti, 1758) (Anura: Hylidae).

Although comparative studies of anuran ontogeny have provided new data on heterochrony in the life cycles of frogs, most of them have not included ossification sequences. Using differential staining techniques, we observe and describe differences and similarities of cranial and postcranial development in two hylid species, Scinax ruber (Scinaxinae) and Dendropsophus labialis (Hylinae), providing new data of ontogenetic studies in these Colombian species. We examined tadpoles raining from Gosner Stages 25 to 45. We found differences between species in the infrarostral and suprarostral cartilages, optic foramen, planum ethmoidale, and gill apparatus. In both species, the first elements to ossify were the atlas and transverse processes of the vertebral column and the parasphenoid. Both species exhibited suprascapular processes as described in other hylids. Although the hylids comprise a large group (over 700 species), postcranial ossification sequence is only known for 15 species. Therefore, the descriptions of the skeletal development and ossification sequences provided herein will be useful for future analyses of heterochrony in the group.

The foliar change in two species of Melaleuca (Myrtaceae): a morpho-anatomic and ontogenetic approach

In Melaleuca minutifolia mature leaves are linear, in Melaleuca micromera scale-like and peltate. This peltation is caused by swollen basal mesophyll without meristematic fusions. Thus, a novel peltation strategy is described. The foliar change of two Australian Melaleuca species (Myrtaceae) was investigated in different ontogenetic stages from cotyledons up to the mature leaf types. In both taxa (M. minutifolia and M. micromera), a strong leaf reduction occurs. While in M. minutifolia the mature leaf type is linear, inverse bifacial and strongly adpressed to the shoot axis, in M. micromera it is scale-like, aequifacial, minute and peltate. The mature leaf type of M. micromera is one of the rare examples of peltation among woody species. The ontogenetic studies on the mature peltate leaf type of M. micromera showed that a shield-like leaf base and typical peltate leaf morphology can be formed, not exclusively by meristematic fusions, as is the case for peltate leaves in the classical sense, but instead by strongly swollen mesophyll, particularly in the basal part of the leaf. While most species with peltate leaves are herbaceous perennials from very moist to aquatic habitats and lack reduced leaves, the four Melaleuca species known with the M. micromera type of peltation are from habitats showing either seasonal water stress, soil infertility or both and all show extreme leaf reduction. Given our morpho-anatomical data, it is clear that, as well as the classical type of peltation, a novel, second strategy for achieving peltation needs to be distinguished. The two types are correlated with quite different environmental conditions.

Floral meristem size and organ number correlation in Eucryphia (Cunoniaceae).

We present a comparative flower ontogenetic study in five species of the genus Eucryphia with the aim of testing whether differences in the organ number observed can be explained by changes in the meristematic size of floral meristem and floral organs. Species native to Oceania, viz. E. milliganii, E. lucida and E. moorei, have the smallest gynoecia with ca. 6 carpels, while the Chilean E. glutinosa and E. cordifolia present more than ten carpels. E. milliganii has the smallest flower with the lowest stamen number (ca. 50), while the other species produce around 200 stamens and more. Standardized measurements of meristematic sectors were taken in 49 developing flowers that were classified into three well-defined ontogenetic stages. Sizes of meristems varied significantly among species within each developmental stage as revealed by ANOVA analyses. Significant regressions between organ number and corresponding meristem size were consistent with the premise that a larger meristem size prior to organ initiation could be determining for a higher organ number. Flower organogenesis in Eucryphia also involves relevant meristem expansion while the organs are initiated, which results in a particular androecium patterning with a chaotic stamen arrangement. Meristem expansion also appears to be slower but more extensive in species with larger initial meristematic size, suggesting that flower phenotype can be determined in ontogeny by this heterochronic interplay of space and time.

THE MORPHOLOGY AND ONTOGENETIC OF TAREBIA GRANIFERA (LAMARCK, 1822) FROM INDONESIA (GASTROPODA: CERITHIOIDEA: THIARIDAE)

The freshwater gastropod Tarebia H. Adams & A. Adams, 1854, are found in rivers, lakes, and other limnetic habitats. In Indonesia, Tarebia granifera (Lamarck, 1822) is the only species within the genus that has a wide distribution. The systematics and identity of this species are still doubtful due to high variation in shell morphology, especially shell height and ornamentation or sculpture of shell. To determine the identity of T. granifera from Lombok, Banten, and Maros, ontogenetic studies have been conducted. The results showed that T. granifera from Lombok produce the highest number of embryonic shells. The number of progeny in the brood pouch from a single individual of T. granifera can vary between 9 to 203 embryonic shells which are found in various stages of 0.22 mm to about 5 mm in size inside the brood pouch.

Revisit the Cavernous Sinus from Fetus to Adult-New and Old Data.

This article highlighted three advances in the study of the cavernous sinus: (1) the initial formation of the sinus reticulum in early development of the sphenoid bone before ossification (2) extension of reticulum of the sinus and connection with other venules, and (3) the cavernous sinus and the nerves evolved inside this sinus during gestation, for example, the trigeminal nerve already formed bundles of motor and parasympathetic components during fetal development. This ontogenetic study further confirmed the cavernous sinus is not a single or a dual set of sinuses, but a group of extensions of venous sinuses or sinusoids. These new insights were integrated with previous understandings of the cavernous sinus to form this review article. Anat Rec, 301:819-824, 2018. © 2017 Wiley Periodicals, Inc.

Ultrastructure and development of non-contiguous stomatal clusters and helicocytic patterning in Begonia.

Helicocytic stomata are characterized by an inward spiral of mesogenous cells surrounding a central stomatal pore. They represent a relatively rare feature that occurs in some drought-tolerant angiosperm species. In some Begonia species with thick leaves, the stomata are not only helicocytic but also clustered into groups that are spaced apart by at least one cell. This paper presents a detailed ontogenetic study of this characteristic non-contiguous stomatal patterning in a developmental and phylogenetic context. Light microscopy and both scanning and transmission electron microscopy were used to examine stomatal development in several species of Begonia. Published reports of stomatal development in Begonia and other angiosperms were reviewed to provide a comprehensive discussion of the evolution of stomatal patterning. Helicocytic stomata develop from meristemoids that undergo a series of oriented asymmetric divisions to produce a spiral of mesogene stomatal lineage ground cells (SLGCs) surrounding a stoma. A clear developmental similarity between anisocytic and helicocytic stomata is positively correlated with the number of iterations of amplifying divisions that result in SLGCs. Stomatal clusters develop from asymmetric divisions in neighbouring SLGCs. Within each cluster, non-contiguous spacing of meristemoids is maintained by asymmetric divisions oriented away from each developing meristemoid. Formation of non-contiguous stomatal clusters in Begonia relies on two primary developmental factors in the epidermis: an inwardly spiralling series of amplifying divisions that result in helicocytic stomata, and the development of a variable number of meristemoids from neighbouring SLGCs within each cluster. Optimization of these features on an angiosperm phylogeny indicates that the occurrence of amplifying divisions could be pre-adaptive for these factors. Both factors have been thoroughly studied in terms of developmental genetics in Arabidopsis, suggesting gene orthologues that could be implicated in Begonia stomatal patterning.

Ontogenetic changes in foot strike pattern and calcaneal loading during walking in young children

The assumption that the morphology of the human calcaneus reflects high and cyclical impact forces at heel strike during adult human walking has never been experimentally tested. Since a walking step with a heel strike is an emergent behavior in children, an ontogenetic study provides a natural experiment to begin testing the relationship between the mechanics of heel strike and calcaneal anatomy. This study examined the ground reaction forces (GRFs) of stepping in children to determine the location of the center of pressure (COP) relative to the calcaneus and the orientation and magnitude of ground reaction forces during foot contact. Three-dimensional kinematic and kinetic data were analyzed for 18 children ranging in age from 11.5 to 43.1 months. Early steppers used a flat foot contact (FFC) and experienced relatively high vertical and resultant GRFs with COP often anterior to the calcaneus. More experienced walkers used an initial heel contact (IHC) in which GRFs were significantly lower but the center of pressure remained under the heel a greater proportion of time. Thus, during FFC the foot experienced higher loading, but the heel itself was relatively wider and the load was distributed more evenly. In IHC walkers load was concentrated on the anterior calcaneus and a narrower heel, suggesting a need for increased calcaneal robusticity during development to mitigate injury. These results provide new insight into foot loading outside of typical mature contact patterns, inform structure-function relationships during development, and illuminate potential causes of heel injury in young walkers.

The growth pattern of Neandertals, reconstructed from a juvenile skeleton from El Sidrón (Spain).

Ontogenetic studies help us understand the processes of evolutionary change. Previous studies on Neandertals have focused mainly on dental development and inferred an accelerated pace of general growth. We report on a juvenile partial skeleton (El Sidrón J1) preserving cranio-dental and postcranial remains. We used dental histology to estimate the age at death to be 7.7 years. Maturation of most elements fell within the expected range of modern humans at this age. The exceptions were the atlas and mid-thoracic vertebrae, which remained at the 5- to 6-year stage of development. Furthermore, endocranial features suggest that brain growth was not yet completed. The vertebral maturation pattern and extended brain growth most likely reflect Neandertal physiology and ontogenetic energy constraints rather than any fundamental difference in the overall pace of growth in this extinct human.

Carapace ontogeny of the bromeliad dwelling ostracod Elpidium bromeliarum Müller, 1880 (Crustacea: Ostracoda)

ABSTRACTOstracods have discontinuous development, marked by ecdyses, and determinate growth. Ontogenetic studies have suggested a pattern of nine postembryonic stages (eight juvenile phases and the adult) for the main freshwater ostracod superfamilies Cypridoidea, Cytheroidea and Darwinuloidea. However, cases of a supposed extra moult in the adult stage have been proposed for some ostracod species, which would amount to 10 postembryonic growth stages. One such example is Elpidium bromeliarum Müller, 1880, a cytheroidean that inhabits tank-bromeliads. The present study is aimed at investigating the ontogenetic development of E. bromeliarum using width and length measurements, as well as carapace and appendage morphology in order to test the existing hypothesis of an additional growth stage in adults of this species. Our results revealed nine postembryonic growth stages (eight juvenile and the adult), with sexual dimorphism beginning its expression in the last juvenile stage. Thus, the ontogenetic development of E. bromeliarum agrees with the overall pattern observed for podocopid ostracods and the hypothesis of 10 postembryonic growth stages was not corroborated. We argue that the inability to differentiate juveniles from adults, or different species from one another, may have misled to the assumption of an additional moult in E. bromeliarum.

Morphology and development of the hyolaryngeal apparatus of Pipa arrabali (Anura: Pipidae)

Two different perspectives guide ontogenetic studies. On one hand, there is a concern with objective processes and the understanding of the underlying mechanisms that governed the appearance of morphological differences between taxa; on the other hand, there are similarities between ontogenetic patterns that are used as phylogenetic characters. One focus of ontogenetic studies is to understand how morphology and timing of development differ among species. Such studies also aim to serve as a guide in proposing hypotheses of homology, especially when extremely modified structures are under scrutiny, such as the hyobranchial apparatus of amphibians. Here, we describe the morphology and development of the hyobranchial apparatus of Pipa arrabali (based on the examination of 51 embryos and six newly hatched specimens). Its morphology is compared to that described in the literature for other species. In P. arrabali, Copula I is absent, Copula II is present, and the ceratobranchials are simple, without spines or cartilaginous rays. In general, the ontogeny of the hyobranchial apparatus of P. arrabali seems to be accelerated when compared with that of other frogs, with some stages being skipped and the absence of some tadpole-specific structures observed in other species of pipids and non-pipids.

Pollen wall ontogeny in Polemonium caeruleum (Polemoniaceae) and suggested underlying mechanisms of development.

By a detailed ontogenetic study of Polemonium caeruleum pollen, tracing each stage of development at high TEM resolution, we aim to understand the establishment of the pollen wall and to unravel the mechanisms underlying sporoderm development. The main steps of exine ontogeny in Polemonium caeruleum, observed in the microspore periplasmic space, are spherical units, gradually transforming into columns, then to rod-like units (procolumellae), the appearance of the initial tectum, growth of columellae in height and tectum in thickness and initial sporopollenin accumulation on them, the appearance of the endexine lamellae and of dark-contrasted particles on the tectum, the appearance of a sponge-like layer and of the intine in aperture sites, the appearance of the foot layer on the base of the sponge-like layer and of spinules on the tectum, and massive sporopollenin accumulation. This sequence of developmental events fits well to the sequence of self-assembling micellar mesophases. This gives (together with earlier findings and experimental exine simulations) strong evidence that genome and self-assembly probably share control of exine formation. It is highly probable that self-assembly is an intrinsic instrument of evolution.

The Development of the Silurian Trilobite Aulacopleura koninckii Reconstructed by Applying Inferred Growth and Segmentation Dynamics: A Case Study in Paleo-Evo-Devo

Fossilized growth series provide rare glimpses into the development of ancient organisms, illustrating descriptively how size and shape changed through ontogeny. Occasionally fossil preservation is such that it is feasible to test alternative possibilities about how ancient development was regulated. Here we apply inferred developmental parameters pertaining to size, shape, and segmentation in the abundant and well-preserved 429 Myr old trilobite Aulacopleura koninckii that we have investigated previously to reconstruct the post-embryonic ontogeny of this ancient arthropod. Our published morphometric analyses associated with model testing have shown that: specification of the adult number of trunk segments (polymorphic in this species) was determined precociously in ontogeny; that growth regulation was targeted (i.e., compensatory), such that each developmental stage exhibited comparable variance in size and shape; and that growth gradients operating along the main body axis, both during juvenile and adult ontogeny, resulted from a form of growth control based on positional specification. While such developmental features are common among extant organisms, our results represent the oldest evidence for them within Metazoa. Herein, the novel reconstruction of the development of A. koninckii permits visualization of patterns of relative and absolute growth and segmentation as never before possible for a fossilized arthropod ontogeny. By conducting morphometric analysis of appropriate data sets it is thus possible to move beyond descriptive ontogenetic studies and to address questions of high interest for evolutionary developmental biology using data from fossils, which can help elucidate both how developmental processes themselves evolve and how they affect the evolution of organismal body patterning. By extending similar analyses to other cases of exceptional preservation of fossilized ontogeny, we can anticipate beginning to realize the research program of “paleo-evo-devo”.

Segmental morphometrics of the olive baboon (Papio anubis): a longitudinal study from birth to adulthood.

The linear dimensions and inertial characteristics of the body are important in locomotion and they change considerably during the ontogeny of animals, including humans. This longitudinal and ontogenetic study has produced the largest dataset to date of segmental morphometrics in a Catarrhini species, the olive baboon. The objectives of the study were to quantify the changes in body linear and inertial dimensions and to explore their (theoretical) mechanical significance for locomotion. We took full‐body measurements of captive individuals at regular intervals. Altogether, 14 females and 16 males were followed over a 7‐year period, i.e. from infancy to adulthood. Our results show that individual patterns of growth are very consistent and follow the general growth pattern previously described in olive baboons. Furthermore, we obtained similar growth curve structures for segment lengths and masses, although the respective time scales were slightly different. The most significant changes in body morphometrics occurred during the first 2 years of life and concerned the distal parts of the body. Females and males were similar in size and shape at birth. The rate and duration of growth produced substantial size‐related differences throughout ontogeny, while body shapes remained very similar between the sexes. We also observed significant age‐related variations in limb composition, with a proximal shift of the centre of mass within the limbs, mainly due to changes in mass distribution and in the length of distal segments. Finally, we observed what we hypothesize to be ‘early biomechanical optimization’ of the limbs for quadrupedal walking. This is due to a high degree of convergence between the limbs’ natural pendular periods in infants, which may facilitate the onset of quadrupedal walking. Furthermore, the mechanical significance of the morphological changes observed in growing baboons may be related to changing functional demands with the onset of autonomous (quadrupedal) locomotion. From a wider perspective, these data provide unique insights into questions surrounding both the processes of locomotor development in primates and how these processes might evolve.