scholarly journals Arm swapping autograft shows functional equivalency of five arms in sea stars

2019 ◽  
Author(s):  
Daiki Wakita ◽  
Hitoshi Aonuma ◽  
Shin Tochinai
Keyword(s):  
Sea Urchins ◽  
Positional Information ◽  
Radial Symmetry ◽  
Evolutionary Strategy ◽  
Tissue Formation ◽  
Sea Star ◽  
Sea Stars ◽  
Patiria Pectinifera ◽  
Functional Equivalency ◽  
Typical Shape

AbstractExtant echinoderms show five-part radial symmetry in typical shape. However, we can find some asymmetry in their details, represented by the madreporite position not at the center, different skeletal arrangement in two of the five rays of sea urchins, and a circular cavity formed by two-end closure. We suspect the existence of any difference in hidden information between the five. In our hypothesis, deep equivalency makes no issue in function even after exchanging the position of rays; otherwise, this autograft causes some trouble in behavior or tissue formation. For this attempt, we firstly developed a method to transplant an arm tip to the counterpart of another arm in the sea star Patiria pectinifera. As a result, seven arms were completely implanted—four into the original positions for a control and three into different positions—with underwater surgery where we sutured with nylon thread and physically prevented nearby tube feet extending. Based on our external and internal observation, each grafted arm (i) gradually recovered movement coordination with the proximal body, (ii) regenerated its lost half as in usual distal regeneration, and (iii) formed no irregular intercalation filling any positional gap at the suture, no matter whether two cut arms were swapped. We here suggest a deep symmetry among the five rays of sea stars not only in morphology but also in physiology, representing an evolutionary strategy that has given equal priority to all the radial directions. Moreover, our methodological notes for grafting a mass of body in sea stars would help echinoderm research involving positional information as well as immunology.

scholarly journals KEANEKARAGAMAN BINTANG LAUT (Asteroidea) DI PANTAI LAMALAKA KECAMATAN ILE BOLENG KABUPATEN FLORES TIMUR

2021 ◽  
Vol 3 (2) ◽  
pp. 57-67
Author(s):  
Yunita Rambu Mbana ◽  
Yanti Daud ◽  
Novi I. Bullu
Keyword(s):  
Relative Density ◽  
Radial Symmetry ◽  
Species Density ◽  
Survey Method ◽  
Sea Star ◽  
Sea Stars ◽  
Species Dominance ◽  
A Value ◽  
Invertebrate Animal ◽  
Quantitative Descriptive

Sea star is an invertebrate animal that is included in the phylum Echinoderms from the Asteroidea class. Radial symmetry is shaped and generally has five or more arms and does not have a frame that helps movement. This study aims to determine the diversity of sea star (Asteroidea) in Lamalaka Beach, Ile Boleng District, East Flores Regency.This research will be conducted in July-August 2019, the location of the study is on the Lamalaka coast, Ile Boleng District, East Flores Regency.The method used is a survey method, based on the presence of Asteroidea species that are considered to represent the area. The steps in data collection are field survey, observation, identifying species in each plot, observing and recording their marphological characteristics.Sampling uses the technique of determining the location of sampling using Area sampling. To identify based on Human and Deloach identification guidelines, 2010. Analysis of the data used in this research is quantitative descriptive and the composition of Asteroidea species can be stated based on visual observations calculating species density, relative density, and dominance index, diversity.Based on the results of the study, found 4 species of Asteroidea, namely Protoreaster nodulosus, Linckia laevigata, Echinaster luzonicus, Astropecten polyacanthus. The highest species density calculation results were found in P. nodulosus species with a value of 0.78 ind / m2. while the lowest species density was found in L.laevigata species with a value of 0.63 ind / m2. The highest relative density was found in P. nodulosus species with a value of 27.64%, and the lowest relative density found in L.laevigata species with a value of 22.35 %. The index of starfish species dominance in Lamalaka Beach, obtained a value of D <0.5, indicates that there are no species that dominate in Lamalaka Beach. The existence of starfish in Lamalaka Beach, Ile Boleng District, East Flores Regency needs to be preserved. One form of effort to preserve it is to conduct monitoring with routine monitoring to monitor the condition of the sea star population in these waters. Besides that, it is also necessary to increase the utilization of sea stars as one of the natural tourism objects and as an Ecoedutourism tourism object. Thus, the presence of starfish will be felt by the wider community so that awareness to maintain the existence of starfish will be increased.

scholarly journals Jenis-Jenis Bintang Laut Dan Bulu Babi (Asteroidea, Echinoidea: Echinodermata) Di Perairan Pulau Cilik, Kepulauan Karimunjawa

2018 ◽  
Vol 21 (1) ◽  
pp. 41
Author(s):  
Retno Hartati ◽  
Endika Meirawati ◽  
Sri Redjeki ◽  
Ita Riniatsih ◽  
Robertus Triaji Mahendrajaya
Keyword(s):  
Sea Urchin ◽  
Sea Urchins ◽  
Habitat Type ◽  
Line Transect ◽  
Sea Star ◽  
Acanthaster Planci ◽  
Sea Stars ◽  
Transect Line ◽  
Linckia Laevigata ◽  
Diadema Setosum

Abstract Types of Star Fish and Sea Urchins (Asteroidea, Echinoidea: Echinodermata) In Cilik Island, Karimunjawa WatersEchinoderms are fundamentally good indicators of health and status of coralline communities in marine waters.  Substrat of  sandy, rububle and coral reefs are good habitat for Asteroidea dan Echinoidea.  This study aim to identify sea star (Asteroidea) and sea urchin (Echinoidea) species from Pulau Cilik waters of Karimunjawa Islands. Asteroidea and Echinoidea observed using the line transect method used, ie subjects within the same distance between the transect and the transect square with observations of 2.5 m on the right and left of transect line line. Morphology, habitat type (substrate & depth) and total number of sea stars and sea urchins at each station were determined. The results showed that Pulau Cilik has six species of Asteroidea (Sea star), ie Linckia laevigata, L. multifora, Neoferdifla ocellata (Family Ophidiasteridae), Luidia alternate (Luidiidae Family), Culcita novaeguineae (Family Oreasteridae) and Acanthaster planci which belongs to Family Acanthasteridae. There were 4 species of Echinoidea Sea urchin) found, i.e. Diadema setosum, D. antillarum, D. savignyi and Echinothrix calamaris, which all were family members of Diadematidae Keywords: Ophidiasteridae, Luidiidae, Oreasteridae, Acanthasteridae, Diadematidae AbstrakEchinodermata pada dasarnya merupakan indikator kesehatan dan status dari terumbu karang di laut. Dasar perairan yang landai dengan substrat pasir, terumbu karang dan pecahan karang yang merupakan habitat bagi hewan jenis Asteroidea dan Echinoidea. Penelitian ini bertujuan untuk mengidentifikasi henis-jenis bitang laut dan bulu babi dari perairan Pulau Cilik, Kepulauan Karimunjawa. Pengamatan Asteroidea dan Echinoidea menggunakan metoda line transect yang dimodifikasi, yaitu mengamati subjek dalam jarak yang sama sepanjang garis transect dan kuadrat transect dengan pengamatan 2,5 m di sebelah kanan dan kiri garis line transect. Morfologi, tipe habitat (substrat & kedalaman) dan jumlah total bintang laut dan bulu babi di tiap stasiun dicatat selanjutnya sampel diidentifikasi berdasarkan ciri morfologi tersebut. Hasil penelitian menunjukkan bahwa di perairan Pulau Cilik ditemukan enam spesies Asteroidea (Bintang Laut), yaitu Linckia laevigata, L. multifora, Neoferdifla ocellata (Famili Ophidiasteridae), Luidia alternate (Famili Luidiidae), Culcita novaeguineae (Famili Oreasteridae) dan Acanthaster planci yang termasuk dalam Famili Acanthasteridae. Species Echinoidea (Bulu Babi) ditemukan 4 spesies  Diadema setosum, D. antillarum, D. savignyi dan Echinothrix calamaris  semua anggota famili Diadematidae.Kata kunci : Ophidiasteridae, Luidiidae, Oreasteridae, Acanthasteridae, Diadematidae

Rate of natural mortality in the sea star Archaster angulatus (Echinodermata: Asteroidea)

2017 ◽  
Vol 98 (7) ◽  
pp. 1689-1693
Author(s):  
John K. Keesing
Keyword(s):  
Size Structure ◽  
Sea Urchins ◽  
Maximum Size ◽  
Life History Strategies ◽  
Natural Mortality ◽  
Sea Star ◽  
Sea Stars ◽  
Instantaneous Rate ◽  
Peak Abundance ◽  
Size At Age

The population size structure from a total of 876 individuals, together with published values of growth rate, maximum size and size at age were used to estimate an instantaneous rate of natural mortality (M) of 0.46–0.59 year−1 in a population of the sea star Archaster angulatus from south-western Australia. Peak abundance (17%) of all animals sampled was 105–109 mm arm radius (means of 4.2–4.8 years of age) and only one per cent of sea stars are predicted to live beyond 8 years in the population studied. There are few comparable studies on sea stars but when compared with rates of natural mortality in other echinoderms (sea urchins), A. angulatus is intermediate among species which exhibit the extremes of life history strategies, that is, those which grow very rapidly and may live just two years or less and those with very slow growth rates and which may live for decades.

scholarly journals The Use of Larval Sea Stars and Sea Urchins in the Discovery of Shared Mechanisms of Metazoan Whole-Body Regeneration

Genes ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 1063
Author(s):  
Andrew Wolff ◽  
Veronica Hinman
Keyword(s):  
Sea Urchin ◽  
Sea Urchins ◽  
Whole Body ◽  
Life Stages ◽  
Sea Star ◽  
Sea Stars ◽  
Regenerative Capacity ◽  
New Models ◽  
Ability To Regenerate ◽  
New System

The ability to regenerate is scattered among the metazoan tree of life. Further still, regenerative capacity varies widely within these specific organisms. Numerous organisms, all with different regenerative capabilities, have been studied at length and key similarities and disparities in how regeneration occurs have been identified. In order to get a better grasp on understanding regeneration as a whole, we must search for new models that are capable of extensive regeneration, as well as those that have been under sampled in the literature. As invertebrate deuterostomes, echinoderms fit both of these requirements. Multiple members regenerate various tissue types at all life stages, including examples of whole-body regeneration. Interrogations in two highly studied echinoderms, the sea urchin and the sea star, have provided knowledge of tissue and whole-body regeneration at various life stages. Work has begun to examine regeneration in echinoderm larvae, a potential new system for understanding regenerative mechanisms in a basal deuterostome. Here, we review the ways these two animals’ larvae have been utilized as a model of regeneration.

Phylum Echinodermata*

Zootaxa ◽  
2007 ◽  
Vol 1668 (1) ◽  
pp. 749-764 ◽  
Author(s):  
DAVID L. PAWSON
Keyword(s):  
Vascular System ◽  
Bilateral Symmetry ◽  
Radial Symmetry ◽  
Sea Star ◽  
Sea Stars ◽  
Fossil Species ◽  
Radial Pattern ◽  
Distinctive Group ◽  
Marine Realm ◽  
Living Species

The Phylum Echinodermata, comprising approximately 7,000 living species, and 13,000 fossil species, is epitomized by the familiar sea star, a universal symbol of the marine realm.  This distinctive group of animals may be briefly defined as possessing a skeleton of calcium carbonate in the form of calcite; a unique water-vascular system which mediates feeding, locomotion, and other functions; and a more or less conspicuous five-part radial symmetry.  A closer look at some extant echinoderms will show that some taxa of sea cucumbers lack calcite in their body walls, some taxa of sea stars have “outgrown” five-part symmetry and may have 50 or more arms, and many echinoderms show a more or less conspicuous bilateral symmetry superimposed upon a radial pattern.  Fossil echinoderms can be even more puzzling, for some are decidedly asymmetrical, and others may lack evidence of a water-vascular system.  Perhaps the only truly reliable taxonomic character of the phylum is that its members today are restricted to the marine realm.

scholarly journals The development and neuronal complexity of bipinnaria larvae of the sea star Asterias rubens

2021 ◽  
Author(s):  
Hugh F. Carter ◽  
Jeffrey R. Thompson ◽  
Maurice R. Elphick ◽  
Paola Oliveri
Keyword(s):  
Nervous System ◽  
Sea Urchins ◽  
Developmental Studies ◽  
Sea Star ◽  
Asterias Rubens ◽  
Sea Stars ◽  
Experimental Systems ◽  
Developmental Progression ◽  
Staining Methods ◽  
Molecular Anatomy

AbstractFree-swimming planktonic larvae are a key stage in the development of many marine phyla, and studies of these organisms have contributed to our understanding of major genetic and evolutionary processes. Although transitory, these larvae often attain a remarkable degree of tissue complexity, with well-defined musculature and nervous systems. Amongst the best studied are larvae belonging to the phylum Echinodermata, but with work largely focused on the pleuteus larvae of sea urchins (class Echinoidea). The greatest diversity of larval strategies amongst echinoderms is found in the class Asteroidea (sea-stars), organisms that are rapidly emerging as experimental systems for genetic and developmental studies. However, the bipinnaria larvae of sea stars have only been studied in detail in a small number of species and the full complexity of the nervous system is, in particular, poorly understood. Here we have analysed embryonic development and bipinnaria larval anatomy in the common North Atlantic sea-star Asterias rubens, employing use of a variety of staining methods in combination with confocal microscopy. Importantly, the complexity of the nervous system of bipinnaria larvae was revealed in greater detail than ever before, with identification of at least three centres of neuronal complexity: the anterior apical organ, oral region and ciliary bands. Furthermore, the anatomy of the musculature and sites of cell division in bipinnaria larvae were analysed. Comparisons of developmental progression and molecular anatomy across the Echinodermata provided a basis for hypotheses on the shared evolutionary and developmental processes that have shaped this group of animals. We conclude that bipinnaria larvae appear to be remarkably conserved across ~200 million years of evolutionary time and may represent a strong evolutionary and/or developmental constraint for species utilizing this larval strategy.

scholarly journals Evidence for a trophic cascade on rocky reefs following sea star mass mortality in British Columbia

PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e1980 ◽  
Author(s):  
Jessica A. Schultz ◽  
Ryan N. Cloutier ◽  
Isabelle M. Côté
Keyword(s):  
British Columbia ◽  
Trophic Cascade ◽  
Sea Urchins ◽  
Fold Increase ◽  
Mass Mortality ◽  
Strongylocentrotus Droebachiensis ◽  
Population Declines ◽  
Sea Star ◽  
Sea Stars ◽  
Study Sites

Echinoderm population collapses, driven by disease outbreaks and climatic events, may be important drivers of population dynamics, ecological shifts and biodiversity. The northeast Pacific recently experienced a mass mortality of sea stars. In Howe Sound, British Columbia, the sunflower starPycnopodia helianthoides—a previously abundant predator of bottom-dwelling invertebrates—began to show signs of a wasting syndrome in early September 2013, and dense aggregations disappeared from many sites in a matter of weeks. Here, we assess changes in subtidal community composition by comparing the abundance of fish, invertebrates and macroalgae at 20 sites in Howe Sound before and after the 2013 sea star mortality to evaluate evidence for a trophic cascade. We observed changes in the abundance of several species after the sea star mortality, most notably a four-fold increase in the number of green sea urchins,Strongylocentrotus droebachiensis, and a significant decline in kelp cover, which are together consistent with a trophic cascade. Qualitative data on the abundance of sunflower stars and green urchins from a citizen science database show that the patterns of echinoderm abundance detected at our study sites reflected wider local trends. The trophic cascade evident at the scale of Howe Sound was observed at half of the study sites. It remains unclear whether the urchin response was triggered directly, via a reduction in urchin mortality, or indirectly, via a shift in urchin distribution into areas previously occupied by the predatory sea stars. Understanding the ecological implications of sudden and extreme population declines may further elucidate the role of echinoderms in temperate seas, and provide insight into the resilience of marine ecosystems to biological disturbances.

H3 histone RNA in eggs and embryos of the sea star Pisaster ochraceus

1988 ◽  
Vol 66 (10) ◽  
pp. 1040-1044
Author(s):  
D. K. Banfield ◽  
J. D. G. Boom ◽  
B. M. Honda ◽  
M. J. Smith
Keyword(s):  
Sea Urchins ◽  
Transcript Abundance ◽  
Single Copy ◽  
Sea Star ◽  
Sea Stars ◽  
Pisaster Ochraceus ◽  
Homologous Sequences ◽  
Order Of Magnitude ◽  
Transcript Concentration ◽  
Rna Concentration

Unlike sea urchins, sea stars have little stored histone RNA in their eggs. In an effort to quantify this difference, we have measured H3 RNA concentration in eggs and embryos of the sea star Pisaster ochraceus. The amount of H3 transcript in P. ochraceus 12-h embryos has been measured by RNA excess hybridization kinetics, using a single-strand 32P-labelled coding sequence probe. There are 1 × 105 H3 transcripts in each 12-h embryo. Putative egg H3 transcript concentration was estimated by reciprocal plots. The number of egg H3 homologous sequences (150/egg) is at least an order of magnitude less than rare complex-class, single-copy nuclear DN A transcripts. Slot blots and Northern blots indicate that sea star embryos do not reach the level of H3 transcript abundance seen in sea urchins until at least 16 h of development.

Skeletal elements of crinoid echinoderms: High-resolution structural and microanalytical results

1983 ◽  
Vol 41 ◽  
pp. 194-195
Author(s):  
D. F. Blake ◽  
L. F. Allard ◽  
D. R. Peacor
Keyword(s):  
High Resolution ◽  
Marine Invertebrates ◽  
Sea Urchins ◽  
Structural Features ◽  
Sea Stars ◽  
High Resolution Tem ◽  
Relationship Of ◽  
The Relationship ◽  
Insight Into

Echinodermata is a phylum of marine invertebrates which has been extant since Cambrian time (c.a. 500 m.y. before the present). Modern examples of echinoderms include sea urchins, sea stars, and sea lilies (crinoids). The endoskeletons of echinoderms are composed of plates or ossicles (Fig. 1) which are with few exceptions, porous, single crystals of high-magnesian calcite. Despite their single crystal nature, fracture surfaces do not exhibit the near-perfect {10.4} cleavage characteristic of inorganic calcite. This paradoxical mix of biogenic and inorganic features has prompted much recent work on echinoderm skeletal crystallography. Furthermore, fossil echinoderm hard parts comprise a volumetrically significant portion of some marine limestones sequences. The ultrastructural and microchemical characterization of modern skeletal material should lend insight into: 1). The nature of the biogenic processes involved, for example, the relationship of Mg heterogeneity to morphological and structural features in modern echinoderm material, and 2). The nature of the diagenetic changes undergone by their ancient, fossilized counterparts. In this study, high resolution TEM (HRTEM), high voltage TEM (HVTEM), and STEM microanalysis are used to characterize tha ultrastructural and microchemical composition of skeletal elements of the modern crinoid Neocrinus blakei.

scholarly journals Sea stars generate downforce to stay attached to surfaces

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Mark Hermes ◽  
Mitul Luhar
Keyword(s):  
Body Shape ◽  
Control Volume ◽  
Water Channel ◽  
Morphological Plasticity ◽  
The Body ◽  
Sea Star ◽  
Sea Stars ◽  
Hydrodynamic Loads ◽  
Spherical Dome ◽  
Star Models

AbstractIntertidal sea stars often function in environments with extreme hydrodynamic loads that can compromise their ability to remain attached to surfaces. While behavioral responses such as burrowing into sand or sheltering in rock crevices can help minimize hydrodynamic loads, previous work shows that sea stars also alter body shape in response to flow conditions. This morphological plasticity suggests that sea star body shape may play an important hydrodynamic role. In this study, we measured the fluid forces acting on surface-mounted sea star and spherical dome models in water channel tests. All sea star models created downforce, i.e., the fluid pushed the body towards the surface. In contrast, the spherical dome generated lift. We also used Particle Image Velocimetry (PIV) to measure the midplane flow field around the models. Control volume analyses based on the PIV data show that downforce arises because the sea star bodies serve as ramps that divert fluid away from the surface. These observations are further rationalized using force predictions and flow visualizations from numerical simulations. The discovery of downforce generation could explain why sea stars are shaped as they are: the pentaradial geometry aids attachment to surfaces in the presence of high hydrodynamic loads.

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