Crinoids Research Articles

Sea Lily Muscle Lacks a Troponin-Regulatory System, While it Contains Paramyosin

Troponin, a Ca(2+)-dependent regulator of striated muscle contraction, has been characterized in vertebrates, protochordates (amphioxus and ascidian), and many invertebrate animals that are categorized in protostomes, but it has not been detected in echinoderms, such as sea urchin and sea cucumber, members of subphylum Eleutherozoa. In this study, we examined the muscle of a species of isocrinid sea lilies, a member of subphylum Pelmatozoa, that constitute the most basal group of extant echinoderms to clarify whether troponin is lacking from the early evolution of echinoderms. Native thin filaments were released from the muscle homogenates in a relaxing buffer containing ATP and EGTA, a Ca(2+)-chelator, and were collected by ultra-centrifugation. Actin and tropomyosin, but not a troponin-like protein, were detected in the filament preparation. The filaments increased Mg(2+)-ATPase activity of rabbit skeletal muscle myosin irrespective of the presence or absence of Ca(2+). The results indicate that Ca(2+)-sensitive factor, troponin, is lacking in the thin filaments of sea lily muscle as in those of the other echinoderms, sea urchin and sea cucumber. On the other hand, a paramyosin-like protein that is absent from chordates was detected in sea lily muscle as in the muscles of the other echinoderms and invertebrate animals of protostomes.

Active feeding behavior of and current modification by the sea lily Metacrinus rotundus (Echinodermata: Crinoidea)

All modern crinoids, categorized as articulate crinoids, possess muscular articulations in their arms that allow them to maintain their feeding posture in changing current conditions. We tested the responses of the isocrinid Metacrinus rotundus to the introduction of suspended particles in the water column and to the chemical properties of the suspended particles (organic versus inorganic), and measured changes in flow patterns during feeding. The crinoids demonstrated specific behavior in response to organic particles in the current, and chemical extracts consisting of organic matter induced a change in the posture. The currents around the crinoids were disturbed by the crinoid arms only when the particles were passing through the arms, and the current speed and direction were maintained within a certain range. Crinoids are considered to actively form an effective filtration fan in the current, detect if organic matter is present in the current, and control and maintain the current condition to maximize their filter feeding. Living stalked crinoids are restricted to the deep sea, and the abovementioned crinoid strategies are key characteristics for their life in an oligotrophic environment. The development of muscular articulation provides not only a free locomotion but also a sophisticated filter feeding mechanism by acquiring an idealized filtration fan.

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.

Ancient ancestor of starfish and sea lilies found in Morocco

Ancient ancestor of starfish and sea lilies found in Morocco

Is the species flock concept operational? The Antarctic shelf case.

There has been a significant body of literature on species flock definition but not so much about practical means to appraise them. We here apply the five criteria of Eastman and McCune for detecting species flocks in four taxonomic components of the benthic fauna of the Antarctic shelf: teleost fishes, crinoids (feather stars), echinoids (sea urchins) and crustacean arthropods. Practical limitations led us to prioritize the three historical criteria (endemicity, monophyly, species richness) over the two ecological ones (ecological diversity and habitat dominance). We propose a new protocol which includes an iterative fine-tuning of the monophyly and endemicity criteria in order to discover unsuspected flocks. As a result nine « full » species flocks (fulfilling the five criteria) are briefly described. Eight other flocks fit the three historical criteria but need to be further investigated from the ecological point of view (here called « core flocks »). The approach also shows that some candidate taxonomic components are no species flocks at all. The present study contradicts the paradigm that marine species flocks are rare. The hypothesis according to which the Antarctic shelf acts as a species flocks generator is supported, and the approach indicates paths for further ecological studies and may serve as a starting point to investigate the processes leading to flock-like patterning of biodiversity.

Fixed, free, and fixed: The fickle phylogeny of extant Crinoidea (Echinodermata) and their Permian–Triassic origin

Although the status of Crinoidea (sea lilies and featherstars) as sister group to all other living echinoderms is well-established, relationships among crinoids, particularly extant forms, are debated. All living species are currently placed in Articulata, which is generally accepted as the only crinoid group to survive the Permian–Triassic extinction event. Recent classifications have recognized five major extant taxa: Isocrinida, Hyocrinida, Bourgueticrinina, Comatulidina and Cyrtocrinida, plus several smaller groups with uncertain taxonomic status, e.g., Guillecrinus, Proisocrinus and Caledonicrinus. Here we infer the phylogeny of extant Crinoidea using three mitochondrial genes and two nuclear genes from 59 crinoid terminals that span the majority of extant crinoid diversity. Although there is poor support for some of the more basal nodes, and some tree topologies varied with the data used and mode of analysis, we obtain several robust results. Cyrtocrinida, Hyocrinida, Isocrinida are all recovered as clades, but two stalked crinoid groups, Bourgueticrinina and Guillecrinina, nest among the featherstars, lending support to an argument that they are paedomorphic forms. Hence, they are reduced to families within Comatulida. Proisocrinus is clearly shown to be part of Isocrinida, and Caledonicrinus may not be a bourgueticrinid. Among comatulids, tree topologies show little congruence with current taxonomy, indicating that much systematic revision is required. Relaxed molecular clock analyses with eight fossil calibration points recover Articulata with a median date to the most recent common ancestor at 231–252mya in the Middle to Upper Triassic. These analyses tend to support the hypothesis that the group is a radiation from a small clade that passed through the Permian–Triassic extinction event rather than several lineages that survived. Our tree topologies show various scenarios for the evolution of stalks and cirri in Articulata, so it is clear that further data and taxon sampling are needed to recover a more robust phylogeny of the group.

Was autotomy a pervasive adaptation of the crinoid stalk during the Paleozoic?

The crinoids were the most diverse and numerically most common echinoderms in the Paleozoic, as well as being one of the most important groups of sessile invertebrates. Autotomy (self-mutilation) in the stem, that is, the casting off of the more distal part, is only known to occur in one extant group of crinoids, the post-Paleozoic isocrinine sea lilies. These crinoids have a long distal stalk with regularly spaced articulations (i.e., cryptosymplexies) adapted for autotomy. They are connected together by short, mutable collagenous tissues that undergo irreversible destabilization during autotomy; the distal opening of the axial canal is then sealed by new growth of calcite. Paleozoic crinoids lacked cryptosymplectial articulations, but have other adaptations that may have singly or collectively facilitated autotomy. These include the linking of adjacent short lengths of stalk (i.e., noditaxes) by short ligaments; the evolutionary trend to narrow the axial canal; occlusion of the axial canal in some species; and the ability to seal the axial canal. Other morphological features of relevance to autotomy include the common division of the stem into morphologically distinct regions and attachment by a distal, recumbent radicular runner. The ability to autotomize the distal stem in many Paleozoic crinoid clades was, at the very least, latent; if overt, it would have facilitated escape from environmental disturbance. It may, in part, explain the great abundance of disarticulated crinoid stem fragments in many Ordovician to Permian sedimentary deposits.

Erratum to: On the swimming function of crinoid cirri

Erratum to: On the swimming function of crinoid cirri

Larval development in the feather star Antedon mediterranea

Echinoderms have been used often as experimental models in developmental biology and evolutionary biology studies. Numerous data on echinoid and asteroid development are available, whereas little is known about crinoid larval biology. This contribution focussed on the life cycle of the Mediterranean feather star Antedon mediterranea. Light and electron microscopy were used to characterize, in detail, the morphology and behaviour of the main larval stages. Similarities and differences with respect to what is already known for other crinoids, and echinoderm species, were explored. In view of the importance of serotonin during settlement and morphogenesis, analyses of the distribution of this molecule were carried out on swimming larvae. Immunolabelling results suggested a role for serotonin in A. mediterranea development, underlining the ancestral importance of this conserved neurotransmitter in deuterostome evolution.

Inhibition of Hepatitis C Virus Replication and Viral Helicase by Ethyl Acetate Extract of the Marine Feather Star Alloeocomatella polycladia

Hepatitis C virus (HCV) is a causative agent of acute and chronic hepatitis, leading to the development of hepatic cirrhosis and hepatocellular carcinoma. We prepared extracts from 61 marine organisms and screened them by an in vitro fluorescence assay targeting the viral helicase (NS3), which plays an important role in HCV replication, to identify effective candidates for anti-HCV agents. An ethyl acetate-soluble fraction of the feather star Alloeocomatella polycladia exhibited the strongest inhibition of NS3 helicase activity, with an IC50 of 11.7 µg/mL. The extract of A. polycladia inhibited interaction between NS3 and RNA but not ATPase of NS3. Furthermore, the replication of the replicons derived from three HCV strains of genotype 1b in cultured cells was suppressed by the extract with an EC50 value of 23 to 44 µg/mL, which is similar to the IC50 value of the NS3 helicase assay. The extract did not induce interferon or inhibit cell growth. These results suggest that the unknown compound(s) included in A. polycladia can inhibit HCV replication by suppressing the helicase activity of HCV NS3. This study may present a new approach toward the development of a novel therapy for chronic hepatitis C.

Vollständig erhaltene Crinoiden im Hauptrogenstein bei Freiburg

Vollständig erhaltene Crinoiden im Hauptrogenstein bei Freiburg

Taxonomic Study on the Feather Stars (Crinoidea: Echinodermata) from Egyptian Red Sea Coasts and Suez Canal, Egypt

A taxonomic study on the crinoids (feather stars) collected from 34 sites from the Red Sea coasts and islands as well as the Suez Canal was done during the period from 1992 to 2003. A total of 15 species are now known from the Red Sea belonging to eleven genera under six families. Among them four species are endemic to the Red Sea and the two spe- cies, Decametra chadwicki and Lamprometra klunzingeri, are recorded from the Suez Canal for the first time. Also, the two species, Oligometra serripinna and Dorometra aegyptica, are new record from Gulf of Suez, and Decametra mollis from Gulf of Aqaba and Northern Red Sea. This study represents the first proper documentation of crinoid species in the study area. Summaries are provided of the specific habitats and geographical distribution.

Late Cretaceous (Santonian-Campanian) sea lilies (Echinodermata, Crinoidea) from the glacial rafts of northwestern Poland

Seven Santonian (Isocrinus? minutus, Tetracrinus jagti, Cyathidium senessei, Bourgueticrinidae indet., Notocrinidae indet., Glenotremites paradoxus, Marsupitestestudinarius) and seven Campanian (Nielsenicrinus carinatus, Austinocrinus sp., Bourgueticrinidae indet., Bourgueticrinus cf. constrictus, B. ellipticus, B.? suedicus, Roveacrinina gen. et sp. indet.) crinoid taxa from the Cretaceous glacial rafts of northwestern Poland (near Wolin Island) are described for the first time. The taphonomy and palaeogeographic implications are discussed. The present assemblage differs taxonomically from the crinoid faunules recently described from the glacial rafts of eastern Poland. However, these faunules are similar to crinoids from the autochthonous Upper Cretaceous sediments of southern and eastern Poland (Miechow Trough, Krakow-Czestochowa Upland, Middle Vistula River valley). An update of Late Cretaceous crinoids from the Miechow Trough and Krakow-Czestochowa Upland is also given.

Glycomics of a novel type-2 N-acetyllactosamine-specific lectin purified from the feather star, Oxycomanthus japonicus (Pelmatozoa: Crinoidea)

A lectin - designated OXYL for the purposes of this study that strongly recognizes complex-type oligosaccharides of serum glycoproteins - was purified from a crinoid, the feather star Oxycomanthus japonicus, the most basal group among extant echinoderms. OXYL was purified through a combination of anion-exchange and affinity chromatography using Q-sepharose and fetuin-sepharose gel, respectively. Lectin was determined to be a 14-kDa polypeptide by sodium dodecyl sulphate-polyacrylamide gel electrophoresis under reducing conditions. However, 14-kDa and 28-kDa bands appeared in the same proportion under non-reducing conditions. Gel permeation chromatography showed a 54-kDa peak, suggesting that lectin consists of four 14-kDa subunits. Divalent cations were not indicated, and stable haemagglutination activity was demonstrated at pH 4-12 and temperatures below 60°C. Surface plasmon resonance analysis of OXYL against fetuin showed k(ass) and k(diss) values of 1.4×10(-6)M(-1)s(-1) and 3.1×10(-3)s(-1), respectively, indicating that it has a strong binding affinity to the glycoprotein as lectin. Frontal affinity chromatography using 25 types of prydylamine-conjugated glycans indicated that OXYL specifically recognizes multi-antennary complex-type oligosaccharides containing type-2 N-acetyllactosamines (Galβ1-4GlcNAc) if α2-3-linked sialic acid is linked at the non-reducing terminal. However, type-1 N-acetyllactosamine (Galβ1-3GlcNAc) chains and α2-6-linked sialic acids were never recognized by OXYL. This profiling study showed that OXYL essentially recognizes β1-4-linkage at C-1 position and free OH group at C-6 position of Gal in addition to the conservation of N-acetyl groups at C-2 position and free OH groups at C-3 position of GlcNAc in N-acetyllactosamine. This is the first report on glycomics on a lectin purified from an echinoderm belonging to the subphylum Pelmatozoa.

Staging of regeneration process of an arm of the feather star Oxycomanthus japonicus focusing on the oral‐aboral boundary

Crinoids have strong regenerative capability and rapidly restore their lost body parts such as arms. We observed the regeneration process of arms of the feather star (stalkless crinoid), Oxycomanthus japonicus, and divided the process into 10 stages. We clarify the position at which the oral and aboral epidermis adhere in wound closure and track the oral-aboral boundary in the regenerate during the entire process of regeneration. We suggest that the concepts of distalization and intercalation, which are proposed to understand animal regeneration integrally, are also applicable to arm regeneration of the feather star. In addition, we clarify that pinnules, appendages extending from the sides of an arm, start to grow in the oral region of the regenerating arm even though a complete pinnule has an oral-aboral axis. The mode of morphogenesis of pinnules in arm regeneration suggests that the oral region functions as the primary patterning tissue for pinnules.

Regeneration in crinoids

Regeneration is a biological phenomenon that occurs in a wide range of animals, and is considered to involve different types of cells including those that are considered to be stem cells. Among the echinoderms, which is a phylum with many regenerating members, crinoids (feather stars and sea lilies) are known to possess high potential of regeneration and are able to regenerate most of their organs. In particular, arm regeneration has been studied using the feather star. During regeneration, coelomocytes and amoebocytes originating from the coelomic canal and the brachial nerve, respectively, migrate to the distal wound area and are involved in the regenerative process. A blastema is formed at the regenerating tip and is derived from migratory amoebocytes. On the other hand, migratory coelomocytes contribute to regenerate the coelomic system. Cells proliferate at the blastema, coelomic canals and brachial nerve. Since the migrating cells differentiate into new structures of the arm, they are considered presumably undifferentiated multipotent stem cells. To deepen our understanding of stem cells in general, we may benefit from an approach from a comparative point of view. Further molecular analyses would increase our knowledge of stem cells in crinoids and allow comparative studies to be possible.

Nervous system development of two crinoid species, the sea lily Metacrinus rotundus and the feather star Oxycomanthus japonicus

Nervous system development in echinoderms has been well documented, especially for sea urchins and starfish. However, that of crinoids, the most basal group of extant echinoderms, has been poorly studied due to difficulties in obtaining their larvae. In this paper, we report nervous system development from two species of crinoids, from hatching to late doliolaria larvae in the sea lily Metacrinus rotundus and from hatching to cystidean stages after settlement in the feather star Oxycomanthus japonicus. The two species showed a similar larval nervous system pattern with an extensive anterior larval ganglion. The ganglion was similar to that in sea urchins which is generally regarded as derived. In contrast with other echinoderm and hemichordate larvae, synaptotagmin antibody 1E11 failed to reveal ciliary band nerve tracts. Basiepithelial nerve cells formed a net-like structure in the M. rotundus doliolaria larvae. In O. japonicus, the larval ganglion was still present 1 day after settlement when the adult nervous system began to appear inside the crown. Stalk nerves originated from the crown and extended down the stalk, but had no connections with the remaining larval ganglion at the base of the stalk. The larval nervous system was not incorporated into the adult nervous system, and the larval ganglion later disappeared. The aboral nerve center, the dominant nervous system in adult crinoids, was formed at the early cystidean stage, considerably earlier than previously suggested. Through comparisons with nervous system development in other ambulacraria, we suggest the possible nervous system development pattern of the echinoderm ancestor and provide new implications on the evolutionary history of echinoderm life cycles.

Chemical fate and biological effects of several endocrine disrupters compounds in two echinoderm species

Two echinoderm species, the sea urchin Paracentrotus lividus and the feather star Antedon mediterranea, were exposed for 28 days to several EDCs: three putative androgenic compounds, triphenyltin (TPT), fenarimol (FEN), methyltestosterone (MET), and two putative antiandrogenic compounds, p,p'-DDE (DDE) and cyproterone acetate (CPA). The exposure nominal concentrations were from 10 to 3000 ng L(-1), depending on the compound. This paper is an attempt to join three different aspects coming from our ecotoxicological tests: (1) the chemical behaviour inside the experimental system; (2) the measured toxicological endpoints; (3) the biochemical responses, to which the measured endpoints may depend. The chemical fate of the different compounds was enquired by a modelling approach throughout the application of the 'Aquarium model'. An estimation of the day-to-day concentration levels in water and biota were obtained together with the amount assumed each day by each animal (uptake in microg animal(-1) d(-1) or ng g-wet weight(-1) d(-1)). The toxicological endpoints investigated deal with the reproductive potential (gonad maturation stage, gonad index and oocyte diameter) and with the regenerative potential (growth and histology). Almost all the compounds exerted some kind of effect at the tested concentrations, however TPT was the most effective in altering both reproductive and regenerative parameters (also at the concentration of few ng L(-1)). The biochemical analyses of testosterone (T) and 17beta-estradiol (E(2)) also showed the ability of the selected compounds to significantly alter endogenous steroid concentrations.

PERMIAN CRINOIDS FROM THE SAIWAN AND KHUFF FORMATIONS,SOUTHEASTERN OMAN

Early Permian (Sakmarian) crinoids are described from six horizons in the Saiwan Formation of the Huqf area of southeastern Oman. Each horizon yielded only one to three taxa. All specimens lived in a shallow water environment characterized by mixed siliciclastic or siliciclastic-carbonate sedimentation. Disarticulated arm plates of an indeterminate articulate crinoid are described from a tempestite bed in the Khuff Formation (Wordian) of the Haushi area. The Saiwan Sakmarian crinoids are some of the earlier, although not the earliest Permian crinoids known. Representatives of both primitive (sycocrinids) and advanced (scytalocrinids, blothrocrinids, texacrinids, and cromyocrinids) cladids and articulates are present in the Saiwan crinoids that are dominated by advanced dendrocrinids and belong to families previously reported from the Carboniferous or Permian. They show greatest affinity to the late Sakmarian/early Artinskian fauna from the Callytharra Formation of Western Australia. New taxa described herein double the number of genera (three) previously reported from the same area. The diversity of the Saiwan crinoids is relatively low when compared to the large faunas reported from Timor, Western Australia, Russia, and North America. However, they show affinity with each of the larger faunas. New taxa described are Coeliocrinus arenaceous n. sp., Moapacrinus ? omanensis n. sp., Huqficrinus biserialis n. gen. and sp., and Campbellicrinus nodosus n. sp.

Europe’s Grand Canyon: Nazaré Submarine Canyon

The Nazare submarine canyon extends similar to 210 km westward from the coast of Portugal, down to a water depth of > 4300 m. The considerable habitat heterogeneity found throughout the canyon is affected by strong currents and high turbidity, especially in the upper parts of the canyon. The canyon morphology comprises steep slopes, scarps, terraces, and overhangs, and a deeply incised thalweg is found in the lower part of the canyon. The seabed within the canyon is composed of varying proportions of rock and sediments that range from sand to fine mud. This great variation in physical environment is reflected by the varied fauna inhabiting the canyon. Diversity tends to decrease with depth, but there is also continual replacement of species with increasing water depth. Certain groups, such as the gorgonians and sea lilies, tend to be found on rocky surfaces, while large protozoans dominate the sediments at 3400-m depth. In addition to describing the fauna of Nazare Canyon, we discuss experiments undertaken as part of the HERMES project to elucidate the ecosystem function processes operating in the deeper parts of the canyon.