Content uploaded by Maria Byrne
Author content
All content in this area was uploaded by Maria Byrne
Content may be subject to copyright.
A preview of the PDF is not available
The feeding behavior of Florometra serratissima (Echinodermata: Crinoidea)
Canadian Journal of Zoology
Abstract
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.
... One prediction of osmotrophy that can be tested using CFD is the distribution of flow; macroscopic osmotrophs would be expected to adopt a morphology and/or position in the water column that distributes flow over their entire absorptive surface (see for example, the distribution of water flow over Charniodiscus fronds in Singer et al., 2012), thus maximizing the potential for nutrient absorption. By contrast, sessile organisms adopting an alternative mechanism such as suspension feeding adopt life positions whereby feeding structures are repositioned in flow [such as crinoid fanssee Baumiller (1997) and Byrne & Fontaine (1981], or they develop morphologies that redirect flow to sites of feeding, such as in thecosomatous pteropods (Gilmer, 1990), upsidedown jellyfish (Santhanakrishnan et al., 2012), and black fly larvae (Chance & Craig, 1986;Lacoursière & Craig, 1993). However, while these flow patterns can be used to infer locations of nutrient acquisition in Ediacaran organisms, they provide little information about actual mechanisms for moving nutrients across body tissues (Liu et al., 2015). ...
Over 3.7 billion years of Earth history, life has evolved complex adaptations to help navigate and interact with the fluid environment. Consequently, fluid dynamics has become a powerful tool for studying ancient fossils, providing insights into the palaeobiology and palaeoecology of extinct organisms from across the tree of life. In recent years, this approach has been extended to the Ediacara biota, an enigmatic assemblage of Neoproterozoic soft-bodied organisms that represent the first major radiation of macroscopic eukaryotes. Reconstructing the ways in which Ediacaran organisms interacted with the fluids provides new insights into how these organisms fed, moved, and interacted within communities. Here, we provide an in-depth review of fluid physics aimed at palaeobiologists, in which we dispel misconceptions related to the Reynolds number and associated flow conditions, and specify the governing equations of fluid dynamics. We then review recent advances in Ediacaran palaeobiology resulting from the application of computational fluid dynamics (CFD). We provide a worked example and account of best practice in CFD analyses of fossils, including the first large eddy simulation (LES) experiment performed on extinct organisms. Lastly, we identify key questions, barriers, and emerging techniques in fluid dynamics, which will not only allow us to understand the earliest animal ecosystems better, but will also help to develop new palaeobiological tools for studying ancient life.
... Phylum Echinodermata is composed of the sea stars (Asteroidea), sea cucumbers (Holothuria), brittle stars (Ophiuroidea), feather stars (Crinoidea), and sea urchins (Echinoidea). All species within this phylum, apart from several predatory Asteroidea, are passive and highly efficient marine filter feeders, algal grazers, or detritivores [1,2]. Members of the Echinoidea have evolved a number of very interesting anatomical and neurobiological features, which we believe could inspire novel robotic designs. ...
Neuromorphic engineering is the approach to intelligent machine design inspired by nature. Here, we outline possible robotic design principles derived from the neural and motor systems of sea urchins (Echinoida). Firstly, we review the neurobiology and locomotor systems of sea urchins, with a comparative emphasis on differences to animals with a more centralized nervous system. We discuss the functioning and enervation of the tube feet, pedicellariae, and spines, including the limited autonomy of these structures. We outline the design principles behind the sea urchin nervous system. We discuss the current approaches of adapting these principles to robotics, such as sucker-like structures inspired by tube feet and a robotic adaptation of the sea urchin jaw, as well as future directions and possible limitations to using these principles in robots.
... Community 2 was also typified by the F. serratissima crinoid. F. serratissima only inhabits areas with specific gentle flow [65], and the highest frequency of F. serratissima corresponded with the local wave base limit at ca. 150 m [11]. Community 3 was defined by the overlap of two foundation taxa (Corallinales spp. ...
Partially owing to their isolation and remote distribution, research on seamounts is still in its infancy, with few comprehensive datasets and empirical evidence supporting or refuting prevailing ecological paradigms. As anthropogenic activity in the high seas increases, so does the need for better understanding of seamount ecosystems and factors that influence the distribution of sensitive benthic communities. This study used quantitative community analyses to detail the structure, diversity, and distribution of benthic mega-epifauna communities on Cobb Seamount, a shallow seamount in the Northeast Pacific Ocean. Underwater vehicles were used to visually survey the benthos and seafloor in ~1600 images (~5 m 2 in size) between 34 and 1154 m depth. The analyses of 74 taxa from 11 phyla resulted in the identification of nine communities. Each community was typified by taxa considered to provide biological structure and/or be a primary producer. The majority of the community defining taxa were either cold-water corals, sponges, or algae. Communities were generally distributed as bands encircling the seamount, and depth was consistently shown to be the strongest environmental proxy of the community-structuring processes. The remaining variability in community structure was partially explained by substrate type, rugosity, and slope. The study used environmental metrics, derived from ship-based multibeam bathymetry, to model the distribution of communities on the seamount. This model was successfully applied to map the distribution of communities on a 220 km 2 region of Cobb Sea-mount. The results of the study support the paradigms that seamounts are diversity 'hotspots', that the majority of seamount communities are at risk to disturbance from bottom fishing, and that seamounts are refugia for biota, while refuting the idea that seamounts have high endemism.
... Rubenstein and Koehl (1977) published a landmark paper linking aerosol filtration theory to modes of filtration utilized by suspension feeders. This study provided a solid conceptual framework within which to interpret the ecology of modern crinoids (Meyer, 1979;Byrne and Fontaine, 1981;Liddell, 1982;Meyer, 1982), and was quickly utilized by paleoecologists to infer and explain niche partitioning and distribution patterns of fossil crinoids (Ausich, 1980;Kammer, 1985;Kammer and Ausich, 1987). An overview of aerosol filtration theory and its application to crinoids can be found in this volume (Baumiller, 1997). ...
Crinoids were a common component of Paleozoic benthic paleocommunities, yet they have been under-utilized in paleoecological analyses. Recent efforts to incorporate disarticulated ossicles into these analyses have greatly increased the robustness of paleoecological patterns noted for the Crinoidea. Analyses of crinoid functional morphology, particularly filtration dynamics, have provided testable hypotheses concerning the distribution of crinoids among benthic environments. These models predict that crinoids with dense-mesh filtration fans should be most common in high energy, shoreward paleoenvironments, whereas open-fan crinoids should be most common in low-energy, offshore paleoenvironments. Review of the Paleozoic fossil
record appears to support these general predictions- from the Late Ordovician to the end of the Paleozoic, dense-fan crinoids are most abundant in nearshore paleoenvironments, whereas open-fan crinoids are most abundant offshore.
The partitioning of crinoid diversity through the Paleozoic shifted through time. Beta diversity was highest in the Ordovician, implying that the early diversification of crinoids was focused on partitioning the benthic landscape among taxa. Beta diversity was quite low by the late Paleozoic, however, local and within-habitat alpha diversity
was much greater than during the Ordovician. This resulted in generally higher levels of eurytopy in the late Paleozoic compared to the Ordovician. Patterns of faunal disassembly associated with regional extinctions in North America during the Ordovician and Permian underscore the differences in the paleoecology of these crinoid faunas.
Recent advances in crinoid functional morphology have been concentrated predominantly in two areas, one involving the study of mutable collagenous tissues (MCTs), and the other dealing with the implications of crinoids' rheophilic nature. The presence of MCTs in crinoid cirri and stalks, and their importance to the function of these structures has been demonstrated in several studies. It has been recently reported that MCTs have contractile properties (Birenheide and Motokawa, 1996); if this is corroborated, it would help resolve many fundamental problems in crinoid functional morphology. Studies of the crinoids in their natural setting have confirmed their predominantly rheophilic nature. The application of the rheophilic paradigm and the principles of physics and engineering to crinoids has provided insights into several areas of crinoid functional morphology, including: (1) mechanics of particle interception—direct interception (and not sieving) as the dominant mode of particle capture by the tube feet (no mucus net); (2) the importance of feeding posture and orientation—(a) bilateral symmetry of the feeding posture (oral side downcurrent), (b) the problems associated with maintaining such a posture under bi- or multi-directional flow (swiveling of pinnules, arms, and /or entire filters); (3) the effect of filter resistivity on fluid interception—solid filters need high ambient current velocities; and (4) the influence of nearest neighbors on fluid interception—side-by-side neighbors might be favored over upstream–downstream neighbors.
Neuropeptides are one of the largest and most diverse families of signaling molecules in animals and, accordingly, they regulate many physiological processes and behaviors. Genome and transcriptome sequencing has enabled the identification of genes encoding neuropeptide precursor proteins in species from a growing variety of taxa, including bilaterian and non-bilaterian animals. Of particular interest are deuterostome invertebrates such as the phylum Echinodermata, which occupies a phylogenetic position that has facilitated reconstruction of the evolution of neuropeptide signaling systems in Bilateria. However, our knowledge of neuropeptide signaling in echinoderms is largely based on bioinformatic and experimental analysis of eleutherozoans—Asterozoa (starfish and brittle stars) and Echinozoa (sea urchins and sea cucumbers). Little is known about neuropeptide signaling in crinoids (feather stars and sea lilies), which are a sister clade to the Eleutherozoa. Therefore, we have analyzed transcriptome/genome sequence data from three feather star species, Anneissia japonica, Antedon mediterranea, and Florometra serratissima, to produce the first comprehensive identification of neuropeptide precursors in crinoids. These include representatives of bilaterian neuropeptide precursor families and several predicted crinoid neuropeptide precursors. Using A. mediterranea as an experimental model, we have investigated the expression of selected neuropeptides in larvae (doliolaria), post-metamorphic pentacrinoids and adults, providing new insights into the cellular architecture of crinoid nervous systems. Thus, using mRNA in situ hybridization F-type SALMFamide precursor transcripts were revealed in a previously undescribed population of peptidergic cells located dorso-laterally in doliolaria. Furthermore, using immunohistochemistry a calcitonin-type neuropeptide was revealed in the aboral nerve center, circumoral nerve ring and oral tube feet in pentacrinoids and in the ectoneural and entoneural compartments of the nervous system in adults. Moreover, functional analysis of a vasopressin/oxytocin-type neuropeptide (crinotocin), which is expressed in the brachial nerve of the arms in A. mediterranea, revealed that this peptide causes a dose-dependent change in the mechanical behavior of arm preparations in vitro—the first reported biological action of a neuropeptide in a crinoid. In conclusion, our findings provide new perspectives on neuropeptide signaling in echinoderms and the foundations for further exploration of neuropeptide expression/function in crinoids as a sister clade to eleutherozoan echinoderms.
Crinoids were a common component of Paleozoic benthic paleocommunities, yet they have been under-utilized in paleoecological analyses. Recent efforts to incorporate disarticulated ossicles into these analyses have greatly increased the robustness of paleoecological patterns noted for the Crinoidea. Analyses of crinoid functional morphology, particularly filtration dynamics, have provided testable hypotheses concerning the distribution of crinoids among benthic environments. These models predict that crinoids with dense-mesh filtration fans should be most common in high energy, shoreward paleoenvironments, whereas open-fan crinoids should be most common in low-energy, offshore paleoenvironments. Review of the Paleozoic fossil record appears to support these general predictions—from the Late Ordovician to the end of the Paleozoic, dense-fan crinoids are most abundant in nearshore paleoenvironments, whereas open-fan crinoids are most abundant offshore.
The partitioning of crinoid diversity through the Paleozoic shifted through time. Beta diversity was highest in the Ordovician, implying that the early diversification of crinoids was focused on partitioning the benthic landscape among taxa. Beta diversity was quite low by the late Paleozoic, however, local and within-habitat alpha diversity was much greater than during the Ordovician. This resulted in generally higher levels of eurytopy in the late Paleozoic compared to the Ordovician. Patterns of faunal disassembly associated with regional extinctions in North America during the Ordovician and Permian underscore the differences in the paleoecology of these crinoid faunas.
Comatulid crinoids, or featherstars, are the dominant group of living crinoids and occur in a wide range of modern marine environments from the intertidal zone to the abyss. This chapter outlines current understanding of comatulid classification, distribution, feeding ecology, diets, predation, and taphonomy. A detailed introduction to morphological features, terms and associated symbology is given together with a discussion of practical aspects of working with specimens and the difficulties associated with species identifications. An artificial key to the families of comatulids is included.
Two species of eoparisocrinid crinoids from the Middle Ordovician Galena Group of northern Iowa and southern Minnesota are described, namely Eoparisocrinus crossmani n.sp. and E. grandei n.sp. The post-larval development of Eoparisocrinus crossmani is examined. The ecological niche of a stalked crinoid is related to four basic parameters: stem length, food groove width, tube-foot spacing, and branch density. Stem length limits the highest elevation above the seafloor. The column of E. crossmani becomes longer during ontogeny due to the formation of new columnals and height growth of old ones. Consequently, individuals gradually "move up' until the adult elevation of about 50 mm is reached. The growth rates of stem length relative to crown size are slow in the youngest and mature animals but rapid in juveniles. The various taxa are more or less separated by different food groove widths at most comparable elevations. This pattern minimizes ecological overlap and probably competition between the different species. -from Author
Evolution does not occur in a vacuum. It takes place against a background of changing conditions, some of a climatic or tectonic nature, some created by organisms themselves. The extent to which the rate and direction of evolution are controlled by organisms is the central question in a debate that has been raging for as long as evolution has been part of the intellectual vocabulary of scientists. In an effort to stimulate empirical work on the subject, we organized a symposium on the contributions that functional morphology and comparative physiology are making to paleobiology. The symposium was held as part of the North American Paleontological Convention on July 1, 1992, at the Field Museum of Natural History in Chicago. This issue of Paleobiology contains all the submitted and accepted papers presented at the symposium.
MOST modern crinoids (Echinodermata) are comatulids, which lack the
stalk characteristic of Palaeozoic crinoids. The specialisation and
adaptation to different ecological niches made possible by loss of the
stalk have resulted in several different ways of spreading the arms and
pinnules in an array for suspension feeding. Until the 1960s, most
observations were based on specimens in aquaria. These suggested that
the comatulids sit on the substratum with the mouth orientated upwards,
the arms stretched out in the form of a broad funnel or collecting bowl.
The crinoid was thought to wait passively for a rain of its food
material from above1. This feeding posture is used by some
deep water crinoids2,3. Direct observations of the feeding
behaviour of a shallow water comatulid in the Red Sea during the 1960s
demonstrated that the arms are withdrawn during the day, but at night
are arrayed in a vertical plane to form a filtration fan. This fan is
orientated perpendicular to a prevailing weak current, filtering some
40,000 1 of water at a current speed of 2 cm s-1 during one
period of activity4. These observations and a review of
deep-sea photographs indicated that modern crinoids favour an
environment with moderate currents and are to some degree
current-seeking (rheophilic)5. Application of these ideas to
the palaeocology of Palaeozoic stalked crinoids suggested that most were
rheophilic, using the stalk to raise the calyx above the substratum and
allowing the arms to be outspread in a planar, circular filtration
fan2. The morphology of some ancient forms, however, was
considered indicative of a rheophobic mode of life.
SUMMARY 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 simi- lar 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. T HIS paper forms part of a comparative study of the histology, functional morphology, and evolution of the tube-foot system of echinoderms. The purpose of this paper is to describe the histological structure of the tube-feet of the crinoid Antedon bifida Pennant and to show that in their basic structure and activities they closely resemble better-known tube-feet, such as those of asteroids (Smith, 1946, 1950) or irregular echinoids (Nichols, 1959 a, b), despite the impression to the contrary given in many textbooks. Besides the tube-feet themselves the structure of adjacent parts of the water-vascular canal is described, since these are shown to be analogous with the ampullae of other extensile tube-feet, and are thus of importance in protraction.
The feeding mechanisms of Ophiocomina nigra have been re-examined. A new mechanism, the mucus-net method, is described for the first time. This is essentially a method of suspension feeding in which seston is trapped in a net of mucous threads between the arm spines. The entangled material is formed into boluses by simultaneous activities of ciliary currents and the tube-feet and is transported to the mouth by the tube-feet.
The food of 3 feather-stars, Lamprometra klunzingeri
Hartlaub, 1890), Heterometra savignii (J. Mller, 1841) and Capillaster multiradiatus (Linnaeus, 1758), from the shallow water of Eilat (Red Sea) was found to be composed of planktonic and semi-benthalic organisms with a strong dominance of zooplankton. Monthly analyses of stomach contents showed seasonal changes in the participation of various systematic units in the diet. Food-comprising organisms were found to be selected according to size, and those measuring up to 400 formed 90% of the diet.
The feeding behavior, living position, and skeletal morphology of 8 species of reef-dwelling Caribbean comatulid crinoids are intimately related to the regime of water movement prevailing in the microhabitat. These adaptations are related to the dependence of the crinoid suspension-feeding mechanism on externally produced water movements for a continuous food supply. Greater numbers of co-occurring comatulid species (6 to 7) and larger populations have been found off Colombia and Panam than off Curaao and Jamaica (4 species). It is suggested that these differences may be related to increased or diversified primary productivity close to the larger land masses. Overal food availability as determined by primary productivity may, thus, be an important factor controlling the regional diversity and abundance of these species.
Ophiopholis aculeata, a suspension feeding brittle star, is capable of removing artificial particles from seawater by some mechanism or mechanisms
other than sieving; the animal can capture a finite proportion of particles in all size classes available from at least 30
to 360 micrometers in diameter. A marked shift in the size distribution of particles caught by the animal toward larger particle
sizes agrees with predictions derived from aerosol filtration theory. Adhesion of particles to the tube feet is strongly dependent
on the presence of fixed charged groups on the surface of the particles.
gestions and criticisms; and to the Director of the Bamfield Marine Station for use of its facilities The phenomenon of aggregation in echinoderms with particular reference to the ophiuroid Ophiocomina nigra (Abildgaard) and the crinoid Antedon bijida (Pennant) A monograph of the existing crinoids
- M Byrne
gestions and criticisms; and to the Director of the Bamfield Marine Station for use of its facilities. BYRNE, M. 1978. The phenomenon of aggregation in echinoderms with particular reference to the ophiuroid Ophiocomina nigra (Abildgaard) and the crinoid Antedon bijida (Pennant). B.Sc. thesis, University College Galway, Ireland. CLARK, A. H., and A. M. CLARK. 1967. A monograph of the existing crinoids. Bull. U.S. Natl. Mus. 82(1): 299-309.