Cycliophora

Wanninger, Andreas; Neves, Ricardo Cardoso

doi:10.1007/978-3-7091-1871-9_5

Cited by 5 publications

(8 citation statements)

References 23 publications

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“…Rabbit antibodies to synthetic FMRFamide (Phe-Met-Arg-Phe-amide) conjugated with bovine thyroglobulin (Immunostar, #20091) were used to detect elements of the pediveliger nervous system. According to published data, the antibody reacts with FMRFamide of various animals including mollusks: gastropods, bivalves, and polyplacophora [12,14,33,36]. The manufacturer has confirmed that these antibodies react with antigens of chitons (Mopalia muscosa), gastropod mollusks (Helix pomatia, Aplysia sp., Ilyanassa obsoleta, Lymnaea stagnalis), and bivalves (Mytilus trossulus).…”

Section: Antibodiesmentioning

confidence: 88%

Comparative Neuroanatomy of Pediveliger Larvae of Various Bivalves from the Sea of Japan

Nikishchenko,

Kolotukhina,

Dyachuk

2023

Biology

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Here, we describe the nervous system structures from pediveligers of eight bivalve species (Callista brevisiphonata, Mactromeris polynyma, Crenomytilus grayanus, Kellia japonica, Mizuhopecten yessoensis, and Azumapecten farreri) with different modes of life in their adult stages, corresponding to the ecological niches that they occupy (burrowing, cemented, byssally attached, and mobile forms). We have identified neuromorphological features of the central and peripheral nervous systems in larval bivalves. We show that the unpaired sensory apical organ is still present in pediveligers along with the developing paired cerebral ganglia characteristic of an adult mollusk. Pediveligers have the pleural ganglia connected to the pedal ganglia via the pedal nerve cords and to the visceral ganglia via the lateral nerve cords. We have found a number of structures of the peripheral nervous system whose presence varies between pediveligers of different species. Mactromeris, Callista, and Pododesmus have 5-HT-immunopositive stomatogastric neurons, whereas the Yesso and Farrer’s scallops have an FMRFamide-immunopositive enteric nervous system. The innervation of the anterior part of the velum is connected to a system of the apical organ and cerebral ganglia, and the innervation of the posterior part is connected to the visceral ganglia. Most differences in the structure of the peripheral elements of the nervous system are species-specific and weakly depend on the ecological niche that pediveligers occupy.

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Section: Antibodiesmentioning

confidence: 88%

Comparative Neuroanatomy of Pediveliger Larvae of Various Bivalves from the Sea of Japan

Nikishchenko,

Kolotukhina,

Dyachuk

2023

Biology

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“…Xenacoelomorpha (Acoela, Nemertodermatida and Xenoturbellida) are thought to branch from the rest of the bilateria very early on. In general, their cleavage is holoblastic, and shares some characteristics with the spiral one (Wanninger, 2015). In Acoela, this cleavage pattern is called duet spiral.…”

Section: Xenacoeloelomorpha + Chaetognathamentioning

confidence: 99%

“…The remaining spiralian phyla display a variety of highly derived forms of spiral cleavage. Many of these deviations from the quartet spiral pattern involve the compressive effect of very elongated eggshells, which produces drastic blastomere rearrangements (Wanninger, 2015). This, in turn, prevents the relative twist between macro and micromeres (Rotifera) and/or even the formation of quartets, thus deleting any spiral appearance (Acanthocephala, Gastrotricha).…”

Section: Spiraliamentioning

confidence: 99%

The Evolution of Cleavage in Metazoans

Brun‐Usan¹,

Salazar‐Ciudad²

2021

Evolutionary Developmental Biology

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Cleavage is the earliest developmental stage. In it, the fertilized oocyte gives rise to a cluster of smaller cells (blastomeres) with a particular spatial pattern (a cleavage pattern). Different metazoan species have different cleavage patterns, but most of them fit into a small set of basic types. The relationship between the phylogeny of a given species and its cleavage pattern is far from direct, but most taxa seem to use the same basic cell processes (such as directed cell division or cell adhesion) to build their cleavage patterns. We assess which are those mechanisms in the first section of this chapter. In a second section, we explore how the combined action of these mechanisms can account for the emergence of particular cleavage patterns in different metazoan taxa and the evolutionary transitions between them.

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“…This is especially the case for well‐studied animals like vertebrates and arthropods. In arthropods, detailed studies of development have been crucial to, for example, correcting old views on the homology of certain structures (Wanninger, 2015).…”

Section: Introductionmentioning

confidence: 99%

“…More recently, this scientific trend has been incorporated into the toolkit of EvoDevo research and has been responsible for some of the most spectacular and unexpected discoveries in the field (Carroll, 2006; Held, 2021). In the case of arthropods, for example, mutants were crucial to discovering the role of homeotic genes in patterning the anteroposterior axis and giving segments and appendages their specific identities (Rosenberg, Lynch & Desplan, 2009; Wanninger, 2015). Nevertheless, despite successes with arthropods and vertebrates, the use of developmental anomalies for the study of EvoDevo in other phyla has not been as prevalent as other types of research more focused on genomics and gene expression patterns.…”

Section: Introductionmentioning

confidence: 99%

Monsters reveal patterns: bifurcated annelids and their implications for the study of development and evolution

2021

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During recent decades, the study of anatomical anomalies has been of great relevance for research on development and its evolution. Yet most animal groups have never been studied under this perspective. In annelids, one of the most common and remarkable anomalies is anteroposterior axis bifurcation, that is animals that have two or more heads and/or tails. Bifurcated annelids were first described in the 18th century and have been occasionally reported since then. However, these animals have rarely been considered other than curiosities, one‐off anomalies, or monsters, and a condensed but comprehensive analysis of this phenomenon is lacking. Such an analysis of the existing knowledge is necessary for addressing the different patterns of annelid bifurcation, as well as to understand possible developmental mechanisms behind them and their evolution. In this review we summarize reports of annelid bifurcation published during the last 275 years and the wide variety of anatomies they present. Our survey reveals bifurcation as a widespread phenomenon found all over the annelid tree. Moreover, it also shows that bifurcations can be classified into different types according to anatomy (lateral versus dorsoventral) or developmental origin (embryonic versus postembryonic, the latter occurring in relation to regeneration, reproduction, or growth). Regarding embryos, three different types of bifurcation can be found: conjoined twins (in clitellates); Janus embryos (two posterior ends with a single head which shows duplicated structures); and duplicitas cruciata embryos (with anterior and posterior bifurcation with a 90° rotation). In adults, we show that while lateral bifurcation can result in well‐integrated phenotypes, dorsoventral bifurcation cannot since it requires the discontinuity of at least some internal organs. The relevance of this distinction is highlighted in the case of the Ribbon Clade, a group of syllid annelids in which some species reproduce by collateral and successive gemmiparity (which involves dorsoventral bifurcation), while others grow by branching laterally. Although most known cases of bifurcation came from accidental findings in the wild or were unintentionally produced, experimental studies resulting in the induction of bifurcation of both embryos and adults are also reviewed. In embryos, these experimental studies show how mechanical or chemical disruption of the zygote can result in bifurcation. In adults, the ventral nervous system and the digestive tract seem to play a role in the induction of bifurcation. Based on the reviewed evidence, we argue that the long‐forgotten study of annelid developmental anomalies should be incorporated into the growing field of annelid EvoDevo and examined with modern techniques and perspectives.

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Cycliophora

Cited by 5 publications

References 23 publications

Comparative Neuroanatomy of Pediveliger Larvae of Various Bivalves from the Sea of Japan

Comparative Neuroanatomy of Pediveliger Larvae of Various Bivalves from the Sea of Japan

The Evolution of Cleavage in Metazoans

Monsters reveal patterns: bifurcated annelids and their implications for the study of development and evolution

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