Collagen-like Structures in Ordovician Graptolite Periderm

Towe, Kenneth M.; Urbanek, Adam

doi:10.1038/237443a0

Cited by 64 publications

(52 citation statements)

References 20 publications

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“…Although the graptolites became extinct at the end of the Palaeozoic, they have close living relations in the living pterobranchs (Rhabdopleura, Cephalodiscus) with a cuticle (periderm) that is essentially identical morphologically. On the basis of comparisons of the ultrastructure of the periderm in the living and fossil forms (Towe & Urbanek 1972;Crowther & Rickards 1977;Crowther 1981), their composition has been interpreted as essentially proteinaceous. Decay experiments and observations on Rhabdopleura demonstrated that the periderm and stolon are highly resistant to decay, remaining intact for months while the zooids decay in days (Briggs et al 1995).…”

Section: Secretionsmentioning

confidence: 99%

Resistant biomacromolecules in the fossil record¹

Bergen

Collinson

Briggs

et al. 1995

Acta Botanica Neerlandica

109

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This paper reviews the occurrence of biomacromolecules in fossil plants and animals. The range of techniques used in their release, preparation, microscopy and chemical analysis is described, as is the role of decay experiments in their investigation. The major plant parts that include resistant macromolecules are discussed: algal cell walls, cuticles, spore and pollen walls, propagules, periderm, secondary xylem, and secretions. The chemistry of animal cuticles preserved in the fossil record is briefly considered; they may incorporate macromolecules of plant origin during diagenesis. Some future directions for research are outlined: characterization of sporopollenin, characterization of extant and extinct tissues and organs, chemosystematic investigations, taphonomic processes, investigation of biomacromolecules in animal fossils.

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Section: Secretionsmentioning

confidence: 99%

Resistant biomacromolecules in the fossil record¹

Bergen

Collinson

Briggs

et al. 1995

Acta Botanica Neerlandica

109

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“…The sediment apparently was rich in organic matter, as suggested by abundant trace fossils of minute infaunal nematodes , larger horizontal burrows, pyritized organic peduncles of lingulate brachiopods , 2015 as well as zooids of probable colonial hydrozoans (Baliński et al 2014). Planktonic and benthic graptolites are common (Maletz & Kozłowska 2013), with their originally collagenous (Towe & Urbanek 1972, Armstrong et al 1984) periderm preserved as coalified matter (transformed into aliphatic polymers: Briggs et al 1995, Gupta et al 2006) and frequently pyrite-filled thecae. This mode of preservation contrasts with that of probable hydroids, the originally organic skeleton of which has been pyritized (Baliński et al 2014).…”

Section: Taphonomymentioning

confidence: 99%

An Early Ordovician clonal organism from China with a zig-zagged suture on branches

Dzik¹,

Baliński²,

Sun³

2016

Bull. Geosci.

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An enigmatic clonal organism from the earliest Floian (Arenig) Fenxiang Formation at Tianjialing in Hubei Province, China and here named Crinisdendrum sinicum gen. et sp. nov., shows a puzzling combination of anatomical characters. Lateral colony branches that originate from tubular stolons are built of C-shaped serial oblique units resembling fuselli and merging along a zig-zagged suture, a set of features generally believed to be unique to pterobranch hemichordates. At least most branches taper near their tips and are closed in a manner resembling the termination of thecae previously reported in the extant pterobranch Rhabdopleura normani. The main drawback of the pterobranch model is that previous observations of terminating thecae in R. normani have neither been confirmed by more recent zoological studies nor explained in functional and developmental terms. Pyritized Crinisdendrum specimens preserved in shale were scanned using X-ray microtomography, enabling restoration of early stages of colony development (astogeny). Pyritic internal moulds of probable thecae, showing their interiors in negative relief, and phosphatized walls of thecae overgrown by black corals were recovered chemically from samples of calcareous intercalations in the Fenxiang Formation. Both sets of specimens exhibit a thread-like cylindrical structure resembling a stolon inside the theca and located below the zigzagged suture. A similar organization of branches also characterizes the feathery colonies of Webbyites from the Early Ordovician Klabava Formation of Bohemia, although these colonies are known in less detail. A new family, Crinisdendridae is proposed to encompass these two genera. Further testing of the hypothesis of a pterobranch affinity for these 470-million-year-old organisms will require a better understanding of the anatomy and growth of extant clonal hemichordates.•

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“…Most of the definitions, explaining basic relationships, have been formulated by Towe & Urbanek (1972, , Crowther & Rickards (1977), Crowther (1981), Urbanek, Mierzejewski & Rickards (in press) and Urbanek & Mierzejewski (1984). Description of graptolite ultrastructure has become increasingly complex as improved techniques of electron microscopy have revealed unsuspected ultrastructural elemental relationships, and have resolved the morphology of some ultrastructural elements.…”

Section: Introductionmentioning

confidence: 99%

Graptolite ultrastructure: evolution of descriptive and conceptual terminology

Rickards

Dumican

1985

Geol. Mag.

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Graptolite ultrastructural studies using SEM and TEM are now more than a quarter of a century old and have reached the stage of routine procedure where material of suitable preservation is to hand. (Specimens may be chemically isolated from the rock or, in SEM and STEM studies, may be retained in the matrix.) Description of ultrastructural elements has evolved from the purely empirical to a conceptual/biological classification following (a) the recognition of the role of collagen fibrils in skeletal construction, and (b) the realization that at least two models of skeletal secretion are possible, each essentially opposed to the other. In this paper old terminology is explained with reference to current practice and the latter is tabulated and referred to the increasing number of described ultrastructural elements. Some of the outstanding problems of interpretation are outlined; and a set of concise, in some cases revised, ultrastructural definitions is given together with illustration, where appropriate, of the ultrastructural element defined.

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Collagen-like Structures in Ordovician Graptolite Periderm

Cited by 64 publications

References 20 publications

Resistant biomacromolecules in the fossil record¹

Resistant biomacromolecules in the fossil record¹

An Early Ordovician clonal organism from China with a zig-zagged suture on branches

Graptolite ultrastructure: evolution of descriptive and conceptual terminology

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Collagen-like Structures in Ordovician Graptolite Periderm

Cited by 64 publications

References 20 publications

Resistant biomacromolecules in the fossil record1

Resistant biomacromolecules in the fossil record1

An Early Ordovician clonal organism from China with a zig-zagged suture on branches

Graptolite ultrastructure: evolution of descriptive and conceptual terminology

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Product

Resources

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Resistant biomacromolecules in the fossil record¹

Resistant biomacromolecules in the fossil record¹