First data on the structure of tubes formed by phoronids
| Autor: | Alexander B. Tzetlin, Elena N. Temereva, Tatiana Shcherbakova |
|---|---|
| Rok vydání: | 2020 |
| Předmět: |
0106 biological sciences
0301 basic medicine Geologic Sediments animal structures Annelid Morphology (linguistics) Phoronis biology Behavior Animal biology.organism_classification Cylinder (gastropod) 010603 evolutionary biology 01 natural sciences Invertebrates 03 medical and health sciences 030104 developmental biology Species Specificity Animals Animal Science and Zoology Phoronis australis Tube (container) Composite material Phoronid Layer (electronics) |
| Zdroj: | Zoology (Jena, Germany). 143 |
| ISSN: | 1873-2720 |
| Popis: | Phoronids are marine benthic animals that live in tubes in soft sediment or hard substrata; the phoronids form the tubes by digging or boring. Epidermal glands produce much of the material of the tube, which is completely imbedded in the soft sediment or hard substrata. The structure of phoronid tubes has not been previously studied in detail. In the current research, the morphology and microstructure of the tubes were studied by light microscopy, histology, and scanning electron microscopy for the following species: Phoronis ijimai, Phoronis svetlanae, Phoronis hipporcrepia, Phoronis australis, and Phoronopsis harmeri. In most of these species, the tube consists of an inner organic cylinder and an external layer. The inner organic cylinder is formed by three layers (inner, middle, and outer) of thin films. Each film is formed by fibers, whose thickness differs in different species. These fibers form a net, whose density is higher in digging phoronids than in boring phoronids. The middle layer is formed by highly compressed thin films. The outer layer is the densest portion of the inner cylinder and is associated with the external layer. The external layer is absent in some species (P. australis) but is well developed in digging phoronids. The differences in the organization of tube are consistent with the biology of each species and depend on the type of substrata and on the life style of the animal. Tube organization substantially differs between phoronids and sedentary annelids: the inner organic cylinder is much thicker in phoronid than in annelid tubes, and the fibers that form films are randomly oriented in phoronids but regularly oriented in annelids. In annelids but not in phoronids, inorganic particles in the external layer are usually surrounded and glued together by organic material. These differences may be used to distinguish phoronid tubes from annelid tubes in present-day benthic samples and also in fossil samples. |
| Databáze: | OpenAIRE |
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