The lophophore and ciliary feeding mechanisms of the brachiopod <i>Crania anomala</i> (Müller)

Atkins, D.; Rudwick, Martin J. S.

doi:10.1017/s0025315400054163

Cited by 25 publications

(27 citation statements)

References 20 publications

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“…During the subsequent spirolophous stage two inhalant streams enter the anterolateral regions of the gape as previously reported by Orton (1914) and Atkins & Rudwick (1962). At times there is only a single exhalant current issuing at the anteromedial region, confirming the previous observations of Orton.…”

Section: Discussionsupporting

confidence: 89%

“…During feeding the valves parted along the entire commissure when the animal was undisturbed, but only along the anterior and lateral regions of the commissure when disturbed as was previously noted by Atkins & Rudwick (1962). In both cases the brachia and cirri would remain contracted so that no water currents were produced.…”

Section: Some Observations On Large Specimensmentioning

confidence: 68%

“…The early developmental stages of the brachia of C. anomala were observed by Rowell (1960). An account of the ciliary feeding mechanisms in specimens of about 2 mm dorsal shell width with a spirolophe of 45 pairs of cirri and above was given by Atkins & Rudwick (1962). The ciliary currents on the mantle lobes and the ciliary feeding mechanisms of adult specimens were first described by Orton (1914).…”

Section: Introductionmentioning

confidence: 99%

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Observations on the ciliary feeding mechanism of the brachiopod Crania anomala

Chuang

1974

Journal of Zoology

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In young Crania anomala with a trocholophe or an early schizolophe one inhalant current enters the anterior gape, filters past the single bell‐shaped cirrous basket and spills out diffusely as exhalant current both anteriorly and laterally. Late schizolophe or early spirolophe forms two separate cirrous baskets which produce two separate inhalant currents: the exhalant current still diffuses out anteriorly and laterally. In later stages either one single exhalant current comes out at the anteromedial region, or three exhalant currents, including an additional one at each posterolateral region. The roof of the visceral cavity is attached in five places to the dorsal valve of Crania to form a mantle recess, an anterior passage and two lateral passages. A hole bored through the dorsal valve into the mantle recess or the anterior passage lets out exhalant current. The palaeobiological significance of this lies in the possible use of the hole in the perforate shell valve of the siphonotretid fossil inarticulate Schizambon australis as an exhalant opening. In this species the hole leads into the mantle recess, which also communicates via a lateral passage with each posterolateral part of the mantle space.

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Section: Discussionsupporting

confidence: 89%

Section: Some Observations On Large Specimensmentioning

confidence: 68%

Section: Introductionmentioning

confidence: 99%

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Observations on the ciliary feeding mechanism of the brachiopod Crania anomala

Chuang

1974

Journal of Zoology

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“…Genera studied include: Lingula (Chuang 1959;Rudwick 1970), Novocrania [as Crania] (Orton 1914;Rowell 1961;Atkins & Rudwick 1962 ), Magasella [as Terebratella] (Rudwick 1962), Notosaria [as Tegulorhynchia], Calloria [as Terebratella or Waltonia], Neothyris (Rudwick 1962(Rudwick , 1970 and Megerlina (Savage 1972). Genera studied include: Lingula (Chuang 1959;Rudwick 1970), Novocrania [as Crania] (Orton 1914;Rowell 1961;Atkins & Rudwick 1962 ), Magasella [as Terebratella] (Rudwick 1962), Notosaria [as Tegulorhynchia], Calloria [as Terebratella or Waltonia], Neothyris (Rudwick 1962(Rudwick , 1970 and Megerlina (Savage 1972).…”

Section: Modern Analoguesmentioning

confidence: 99%

A reappraisal of feeding current systems inferred for spire-bearing brachiopods

Manceñido¹,

Gourvennec²

2007

Earth and Environmental Science Transactions of the Royal Socie

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International audienceSpire-bearing brachiopods formally comprise four different rhynchonelliform orders. A calcified spiral brachidium (presumably supporting a spirolophe when alive) and variable median fold and sulcus (probably aiding separation of incurrent from excurrent flows) are peculiar characteristics they all share. Inferences regarding feeding current systems for these extinct taxa have long remained controversial. Two rival models (the Williams–Ager model and the Rudwick–Vogel model) have been developed, each of which has gained supporters as well as critics over the years. In this present paper they are both contrasted and reassessed on the basis of available evidence, together with a new approach that combines: (a) a morpho-functional analysis applying the plankton net as a suitable seston-collecting paradigm; (b) a review of actualistic data showing that all extant spirolophes are functionally inhalant (irrespective of water entering the valves laterally or not); (c) an evaluation of known outcomes from flume experiments yielding consistent empirical results where gaping shells are oriented transversally and dorsally upcurrent; and (d) a reappraisal of the distributions of certain epizoobionts and endosymbionts revealing compatible patterns. The evidence thus accumulated supports the main conclusion that, in most groups (with laterally tapering spiralia), the inhalant current was located medially with the exhalant currents on either side; only in atrypides (with centrally to dorsally tapering spiralia) does the reverse situation appear to have occurred

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“…For example, craniiforms and linguliforms possess a circumferential mantle cavity, a muscle system with oblique muscles, and two pairs of shell adductors, a transitional median tentacle during lophophore development and a median division of the brachial canals into two separate cavities within the lophophore. Craniiforms and rhynchonelliformes exhibit a proteinaceous calcitic shell, a single row of tentacles on a trocholophous lophophore, gonads suspended in the mantle sinus, and lecithotrophic larvae (Rowell 1960;Atkins and Rudwick 1962;Williams et al 1996).…”

Section: Introductionmentioning

confidence: 99%

Neuromuscular development in Novocrania anomala: evidence for the presence of serotonin and a spiralian‐like apical organ in lecithotrophic brachiopod larvae

Altenburger

Wanninger

2010

Evolution and Development

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The phylogenetic position of Brachiopoda remains unsettled, and only few recent data on brachiopod organogenesis are currently available. In order to contribute data to questions concerning brachiopod ontogeny and evolution we investigated nervous and muscle system development in the craniiform (inarticulate) brachiopod Novocrania anomala. Larvae of this species are lecithotrophic and have a bilobed body with three pairs of dorsal setal bundles that emerge from the posterior lobe. Fully developed larvae exhibit a network of setae pouch muscles as well as medioventral longitudinal and transversal muscles. After settlement, the anterior and posterior adductor muscles and delicate mantle retractor muscles begin to form. Comparison of the larval muscular system of Novocrania anomala with that of rhynchonelliform (articulate) brachiopod larvae shows that the former has a much simpler muscular organization. The first signal of serotonin-like immunoreactivity appears in fully developed Novocrania anomala larvae, which have an apical organ that consists of four flask-shaped cells and two ventral neurites. These ventral neurites do not stain positively for the axonal marker alpha-tubulin in the larval stages. In the juveniles, the nervous system stained by alpha-tubulin is characterized by two ventral neurite bundles with three commissures. Our data are the first direct proof for the presence of an immunoreactive neurotransmitter in lecithotrophic brachiopod larvae and demonstrate the existence of flask-shaped serotonergic cells in the brachiopod larval apical organ, thus significantly increasing the probability that this cell type was part of the bauplan of the larvae of the last common lophotrochozoan ancestor.

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The lophophore and ciliary feeding mechanisms of the brachiopod Crania anomala (Müller)

Cited by 25 publications

References 20 publications

Observations on the ciliary feeding mechanism of the brachiopod Crania anomala

Observations on the ciliary feeding mechanism of the brachiopod Crania anomala

A reappraisal of feeding current systems inferred for spire-bearing brachiopods

Neuromuscular development in Novocrania anomala: evidence for the presence of serotonin and a spiralian‐like apical organ in lecithotrophic brachiopod larvae

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