Antedon Bifida Research Articles

Metal concentrations in echinoderms: Assessing bioindicator potential and ecological implications

This study investigates the concentrations of heavy metals and trace elements in five echinoderm species: Holothuria (Platyperona) sanctori, Arbacia lixula, Coscinasterias tenuispina, Ophioderma longicaudum, and Antedon bifida. Given their ecological significance and potential as a food source, understanding the presence and transfer of heavy metals in these species is crucial. Sampling was conducted in 2022 in Canary Islands. Analysis using ICP-OES revealed concentrations of Zn, Cd, Pb, Cu, Ni, Cr, and Fe in mg/kg. The results showed a consistent sequence of metals across all species, with Fe > Zn > Cu > Ni > Cr > Pb > Cd. Holothurians exhibiting the highest levels, followed by sea urchins. Starfish and brittle stars showed similar, lower concentrations, while crinoids exhibited the lowest levels, consistent with their filter-feeding behavior. The findings highlight the potential of holothurians as bioindicators for environmental pollutants. Understanding the role of these echinoderms as bioindicators is essential for assessing ecosystem health and informing conservation efforts in subtropical marine environments.

The genome sequence of the Rosy Feather Star, Antedon bifida (Pennant, 1777)

We present a genome assembly from an individual Antedon bifida (the Rosy Feather Star; Echinodermata; Crinoidea; Comatulida; Antedonidae). The genome sequence is 319.6 megabases in span. Most of the assembly is scaffolded into 11 chromosomal pseudomolecules. The mitochondrial genome has also been assembled and is 15.84 kilobases in length.

Morphology, Immunology of Antedon Bifida (Echinodermata)

Antedon bifida, belongs to the class of Crinoïds. It’s an ancestral ECHINODERMATA. The body is a concave disc surrounded by ten pinnately divided arms, giving it a fem-like appearance. It possesses an axial organ similar to the sea star one : a primitive immune organ. We discover in it : 1) An IGKAPPA Gene recalling the IPA (Invertebrate Primitive Antibody) 3) A Fc receptor gene witch matches with human Fc gene 4) At Last MHC genes.

Evidence of immune genes in the crinoïd: Antedon bifida evidence of A.bifida Igkappa gene and a FC receptor one

Immuno-genomics studies realized in Echinodermata (Invertebrates) were surprising. 3 classes out of 5 Echinodermata presented an IGKappa gene and a Fc receptor gene. It was, first demonstrated, in Asterids and Ophuirids. It was, secondly clearly shown, in the ancestral Crinoid: Antedon bifida

Records of the feather star shrimp Hippolyte prideauxiana in the Orkney Islands and Shetland Islands, northern Scotland—a geographical range expansion

The decapod Hippolyte prideauxiana is a cryptic commensal of the crinoid Antedon bifida , giving rise to its common name ‘the feather star shrimp’. In 2010 and 2013 H. prideauxiana was recorded in the Shetland Islands and the Orkney Islands (‘north isles’), northern Scotland. These observations widen the known geographical distribution of this species by 400 km north from the west coast of Scotland where it was first recorded in 1997. Whilst it is possible that these new records are the result of a range expansion due to climate change it is more likely that this species has been overlooked due to its cryptic coloration, limited awareness of this species and increase in survey effort in the north of Scotland using SCUBA.

Molecular approach to echinoderm regeneration.

Until very recently echinoderm regeneration research and indeed echinoderm research in general has suffered because of the lack of critical mass. In terms of molecular studies of regeneration, echinoderms in particular have lagged behind other groups in this respect. This is in sharp contrast to the major advances achieved with molecular and genetic techniques in the study of embryonic development in echinoderms. The aim of our studies has been to identify genes involved in the process of regeneration and in particular neural regeneration in different echinoderm species. Our survey included the asteroid Asterias rubens and provided evidence for the expression of Hox gene homologues in regenerating radial nerve cords. Present evidence suggests: 1) ArHox1 expression is maintained in intact radial nerve cord and may be upregulated during regeneration. 2) ArHox1 expression may contribute to the dedifferentiation and/or cell proliferation process during epimorphic regeneration. From the crinoid Antedon bifida, we have been successful in cloning a fragment of a BMP2/4 homologue (AnBMP2/4) and analysing its expression during arm regeneration. Here, we discuss the importance of this family of growth factors in several regulatory spheres, including maintaining the identity of pluripotent blastemal cells or as a classic skeletal morphogenic regulator. There is clearly substantial scope for future echinoderm research in the area of molecular biology and certain aspects are discussed in this review.

Occurrence and Activity of Mobile Macrofauna on a Sublittoral Reef: Diel and Seasonal Variation

Underwater television observations were made of mobile macrofauna inhabiting two parts of a sublittoral reef on the west coast of Scotland for 48 h periods in spring, summer, autumn and winter. Continuous occurrence profiles (mean hourly frequency of occurrence, %) were detailed for 12 species of fish (Chirolophis ascanii, Conger conger, Ctenolabrus rupestris, Lepadogaster candollei, Myoxocephalus scorpius, Pholis gunnellus, Pollachius pollachius, Raniceps raninus, Phrynorhombus regius, Zeugopterus punctatus, Thorogobius ephippiatus and Trisopterus minutus), ten crustacean species (Cancer pagurus, Carcinus maenas, Galathea strigosa, Homarus gammarus, Inachus spp., Munida rugosa, Necora puber, Brachyuran sp., Caridean sp. and Pagurid sp.) and four echinoderm species (Antedon bifida, Asterias rubens, Hemicia oculata and Solaster endeca). Rhythmic patterns of diel activity and/or occurrence were identified for several species. Chirolophis ascanii, Ctenolabrus rupestris, L. candollei, Myoxocephalus scorpius, Pholis gunnellus, Pollachius pollachius, Thorogobius ephippiatus, Trisopterus minutus and Munida rugosa were predominantly diurnal, but Ctenolabrus rupestris, Myoxocephalus scorpius and Trisopterus minutus also showed some evidence of crepuscular activity. Raniceps raninus activity was predominantly nocturnal but became continuous in summer. In other species (the topknots Phrynorhombus regius and Z. punctatus and the crustaceans Cancer pagurus and Homarus gammarus) identifiable occurrence patterns changed with season or site. The greatest number of fish species occurred in winter with Myoxocephalus scorpius, Pollachius pollachius and topknots (Phrynorhombus regius and Z. punctatus) showing greater occurrence/activity during spring and winter. Co-occurrence analysis was used to identify species interactions or avoidances.

Functional Morphology of the Introvert and Digestive System of Myzostoma cirriferum (Myzostomida)

AbstractMyzostoma cirriferum feeds by diverting food particles carried by the ambulacral grooves of its comatulid host Antedon bifida. When searching for food, the myzostome uses its protrusible introvert to fulfil two major functions: sensory perception and the capture of food particles. The digestive system is composed of four parts, viz. a pharynx, that is contained within the introvert, a stomach, a series of paired caeca and an intestine that lie in the myzostome's trunk. The pharynx is supplied with a thick muscle which, thanks to peristaltic movements, carries food particles from the mouth to the stomach. Both stomach and caecal cells are able to absorb dissolved nutriments and to store lipids, whereas intestinal cells are only capable of absorption. Due to the beating of their cilia, stomach cells also carry food particles into the caecal lumen, where they are subjected to endocytosis and intracellular digestion by caecal cells. Undigested food fragments eventually gather in a very large, apical vacuole, and the cell apices containing vacuoles are eliminated into the caecal lumen by an apocrinal process. Detached cell apices reach the stomach, where they are embedded in a matrix, together forming a spindle‐shaped faecal mass that is expelled through the postero‐ventral anus. The observed digestive process—entailing the regular elimination of the apical part of the caecal digestive cells—appears to be unique among the Spiralia.

Reproductive seasonality in the comatulid crinoidAntedon bifida(Pennant) from the English Channel

Genital pinnules from the north east Atlantic comatulid crinoid Antedon bifida (Pennant) were sampled monthly over a five-season period , from a site at Berry Head , English Channel, U .K .A. bifidauniquely broods its spawned ova and early larvae, during the period May to July . Nevertheless, a high level of sexual maturity was maintained throughout the annual cycle in both males and females. Three cellular gametogenic features: facets on the mature oocyte cell wall, nutritive phagocytes in the gonad lumen and yolk nuclei in the pre-vitellogenic oocytes, were present at all times of the seasonal cycle. Development of gonads along the length of an arm was not synchronous. All specimens sampled had pinnules, sections of arm or whole arms missing, an damean of 17% of all pinnules from the population were missing or regenerating The commonest small fish in the area, Crenilabrus was observed to nibble oil the genital pinnules. A strategy is suggested involving toleration of such losses, in place of less-expendable parts of the body.

The skeleton of the stalked stages of the comatulid crinoid Antedon bifida (Echinodermata)

The cystidean calyx of Antedon bifida (Pennant, 1777) consists of two superposed series of five inter-radially located plates called basals (lower plates) and orals (upper plates). A single radianal and five radial plates develop in early pentacrinoids. They are radially located between the orals and the basals and alternate with them. During pentacrinoid life, radials grow continuously while orals progressively regress. Basals fuse to the proximal forming the so-called rosette, and the radianal grows till the anal cone is formed and then regresses. The first primibrachials arise in 25 day pentacrinoids. Arms of detached juveniles usually have 13 secundibrachials, with IIBr13 each having a developing pinnule. No infrabasal develops between the series of basals and the upper columnal. During pentacrinoid life, the stalk progressively changes from homeomorphic to xenomorphic while most columnal articulations change from symmorphies to synarthries. Synarthrial fulcral ridges can rotate about 60° from one columnal articulation to another, allowing the stalk to be flexible in every direction. Formation of new columnals is continuous until the proximal appears (i.e. in 65 day pentacrinoids). The number of columnals in the fully-formed pentacrinoid stalk varies from 17 to 24 depending on the individual. Developing cirri are seen in 70 day pentacrinoids. Detached juveniles have two well-developed series of five cirri, which usually consist of ten cirral ossicles.

Oxygen consumption in two shallow-water comatulid crinoids

Rates of oxygen consumption in the two shallow-water comatulid crinoids Antedon bifida bifida Pennant from Ireland and Nemaster rubiginosa Pourtalés from Jamaica are similar to that in other marine poikilothermic invertebrates when expressed in terms of dry tissue weight. The exponent b in the power function Y = a· X b , relating weight-specific respiration to body weight, averaged 0.6. The Q 10 of the weight-independent metabolic rate of both species suggests thermal adaptation to their respective environmental temperatures.

Functional morphology of the podia and ambulacral grooves of the comatulid crinoid Antedon bifida (Echinodermata)

Feeding units — viz. triplets of unequally-sized podia associated with protective lappets — occur all along the pinnules of adult Antedon bifida (Pennant). Small food particles are trapped by direct mucus impingement to the wall of primary and secondary podia (there are no mucus net or mucus thread helping in this process). Large particles are caught by primary and secondary podia which partly curl over them. Small particles accumulate on the collecting podia before being transferred to the groove, while large particles are transferred one by one. Transfer of particles to the groove occurs by wiping the collecting podia on the ciliary tracts against the ciliary current. When active, tertiary podia always paddle against the ciliary current. They serve in bolus formation (mucus embedding of food particles), but do not participate in bolus compaction or propulsion. Elimination of unwanted particles occur through the action of secondary podia whose movements may disrupt the lappet's palisade, thus creating a sideward current that moves particles from the groove to the outside. Typical podial triplets do not occur along brachial and calycinal grooves. Both brachial and calycinal podia function mostly in guiding and regulating particle flow. The feeding structures of early pentacrinoid larvae of Antedon bifida recall to mind those of pinnules of adult individuals. They consist of twenty-five podia arranged in five radial triplets alternating with five interradial pairs. They are similar to the pinnular feeding structures of adults in that they have both collecting (radial) and paddling (interradial) podia.

Nervously mediated change in the mechanical properties of the cirral ligaments of a crinoid

The cirri of crinoid echinoderms are jointed appendages which show variable rigidity but lack muscles. The cirral joints are subtended by collagenous ligaments which determine the passive mechanical behaviour of cirri under tensile load. Creep and stress relaxation tests were performed on the cirri of Antedon bifida. In rigid, initially flexed cirri, the ligaments behave like stiff visco‐elastic solids. When the external K‐ion concentration is elevated by as little as 5 mM, the ligaments become pliant, allowing such cirri to straighten under low loads. Responsiveness to K is depressed or abolished by anaesthetic agents. It requires external Ca, but Sr or Ba can be substituted for Ca. It is enhanced by excess Ca or Mg‐lack, and inhibited by Ca‐lack, excess Mg, or Mn, Co, and La ions. The cirral ligaments are known to be permeated by the processes of neurosecretory‐like cells which are innervated by a branch of the cirral nerve. It is argued that the response to K is nervously mediated and that by depolariz...

The feeding behaviour of Florometra serratissima (Echinodermata: Crinoidea)

The feeding behaviour of the comatulid crinoid Florometra serratissima (A. H. Clark) was studied at two sites around Vancouver Island. It appears to inhabit areas where currents are slight. The arms are held in a cone posture during slack water but in mild currents they orient to form a partial arm fan.Tube foot behaviour was observed in situ and in aquaria. The podia arise in groups of three, each podium of the triplet exhibiting a characteristic behaviour related to its role in feeding. The primary podia are typically held extended; they initiate the mechanism of particle capture, secrete mucous threads, and are sensory. The secondary podia, attached to the lappet for much of their length, scoop to collect particles and perhaps mucous threads. The tertiary podia manipulate material in the food grooves. Lappet action appears to aid particle collection through scraping along the primary podia.These feeding activities are compared with those reported for Antedon bifida (Pennant) and other crinoids.

Observations on the food of Antedon bifida (Echinodermata: Crinoidea)

The gut contents of specimens of the temperate crinoid Antedon bifida (Pennant) were collected from Dalkey, County Dublin, at monthly intervals for 1 yr, and occasionally from other areas around the Irish coast. Quantitative analysis showed the main components to be detritus (65%), plankton (18%) and inorganic particles (17%). This composition was remarkably constant throughout the year and at all locations, the main variation being in the plankton which was at a minimum in February (4%) and reached a maximum in August (36%). Food particle collection appeared to be nonselective within the appropriate size group, the essential feature of a particle being that it would fit into the ambulacral groove. Fragile planktonic diatoms and dinoflagellates, which occurred in blooms in summer and autumn, were digested by A. bifida, but more robust diatoms passed intact through the gut. Histochemical investigations indicate that the bulk of the detritus is refractory, and it is suggested that its associated micro-flora and micro-fauna may be a major source of nutriment for this crinoid.

The feeding behaviour of the featherstar Antedon bifida (Echinodermata: Crinoidea)

The ecology and feeding behaviour of Antedon bifida bifida (Pennant) were studied in situ at five sites on the east and west coasts of Ireland. These encompassed a range of different habitats and hydrographic conditions, including currents of varying intensity, oscillations due to wave action, and multidirectional water movements.Unlike other comatulids hitherto studied, this species was found to be relatively unspecialized in its choice of habitat and to display great flexibility of movement in its arms and pinnules which enable it to adapt to and feed in each of the different types of water movements described. Neither diurnal nor tidal feeding rhythms were observed, the animals being found to feed almost continuously. The relatively unspecialized nature of this species is discussed in relation to the almost cosmopolitan distribution of the genus Antedon.

The fine structure of the yolk nucleus in oocytes of Antedon bifida (Pennant) (Echinodermata: Crinoidea)

The yolk nucleus of Antedon bifida is a large, intensely basophilic structure located in the cytoplasm of small to medium-sized oocytes. Electron microscopy reveals that this yolk nucleus is a conglomeration of hundreds of dense clumps. Each clump, which is a micrometer or two in diameter, consists of finely fibrogranular material in which are embedded ribosome-like particles. Also present in the oocyte cytoplasm are perinuclear dense granules, which may well be the precursors of the clumps making up the yolk nucleus. The yolk nucleus does not appear to participate directly in the elaboration of the yolk granules.

The Histology and Activities of the Tube-feet of Antedon bifida

ABSTRACT The histology of the tube-feet and adjacent parts of the water-vascular canal of the crinoid Antedon bifida is described. The tube-feet possess the same basic structure as other, better-known tube-feet; here, however, they are adapted to collect food particles. They shoot out mucus by means of special muscle-operated glands and bend rapidly inwards to waft the mucus with entrapped particles into the food-grooves. The protraction of the tube-feet is probably brought about by a mechanism very similar to the ampulla system of other extensile tube-feet, but here the contraction of restricted portions of the water-vascular canal provides the necessary hydrostatic pressure.

Papers from the Department of Marine Biology of the Carnegie Institution of Washington Vol xvi Studies in the Development of Crinoids

THE early stages in the life-history of recent crinoids have always been regarded with interest, because it was hoped that they would throw light on the evolution of this class, so rich and various in ancient seas, and on its relation to the other very differently fashioned classes of Echinoderma. Unfortunately, the only forms that have up till now furnished material for the em-bryologist are the unstalked comatulids, or feather-stars, and in the past such material has come from but a single genus, and from only three closely allied species of it—Antedon bifida of our own coasts, A. mediterranea, and A. adriatica. The accounts of their development by W. B. Carpenter, Bury, Seeliger, and others have shown slight differences, due, in part, probably to specific distinctness of the material. Even if it were not feasible to obtain the early stages of any stalked crinoid, still a study of other species, representing other genera of comatulids, was much to be desired, since it might then be possible to infer which features were peculiar to Antedon and which were common to comatulids generally, if not to the whole class Crinoidea. Such a study has now been made by Dr. Morten-sen, who has obtained a fairly complete series in four genera, and the pentacrinoid larvae of two others. His results are set forth in clear English with his usual care, and the memoir is illustrated by admirable drawings from his own pencil. His many interesting results are discussed in a “General Part” which demands the attention of professed morphologists. Here we shall select for comment a few observations that bear on the past history of the class. Papers from the Department of Marine Biology of the Carnegie Institution of Washington. Vol. xvi. Studies in the Development of Crinoids. By Th. Mortensen. (Publication No. 294.) Pp. v + 94+xxviii plates. (Washington: The Carnegie Institution of Washington, 1920.) 6 dollars, post free.