Functional morphology of the membranous lobe within the preoral cavity of Thenus orientalis (Crustacea: Scyllaridae)

Johnston, D.J. (1994) Functional morphology of the membranous lobe within the preoral cavity of Thenus orientalis (Crustacea: Scyllaridae). Journal of the Marine Biological Association of the United Kingdom, 74 (4). pp. 787-800.

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The membranous lobe of Thenus orientalis (Lund) is a broad fleshy protuberance arising midventrally from the sternal skeleton between the second maxillipeds. Its position, morphology and structure are described and its association with the metastome of other crustaceans discussed. Several roles during ingestion can be postulated. The lobe extends anteriorly towards the mandibles and forms the roof of the preoral cavity and posterior boundary of the mouth. It has a flattened strengthening rod extending the width of the aboral surface, which is covered by three types of anteriorly-directed annulate setae and densely arranged clusters of microscales and microspines. Histologically it is characterized by large amounts of longitudinal and circular striated muscle and tegumental glands beneath the oral surface. These glands secrete sulphated acidic mucopolysaccharides which lubricate food during ingestion. Spherical cells are dispersed throughout the connective tissue beneath the aboral surface. These are characterized by a granular homogeneous cytoplasm, a peripheral cell nucleus and few organelles. Their contents stain positively for protein and neutral mucopolysaccharides and their role is most likely storage of these compounds, although the significance of this is not known. During ingestion, food is passed over the lobe surface and its anterior lip retracts ventro-posteriorly, dilating the preoral cavity to allow quick and efficient swallowing of large food items.

Item ID: 27255
Item Type: Article (Research - C1)
ISSN: 1469-7769
Date Deposited: 30 May 2013 00:36
FoR Codes: 06 BIOLOGICAL SCIENCES > 0603 Evolutionary Biology > 060301 Animal Systematics and Taxonomy @ 33%
06 BIOLOGICAL SCIENCES > 0606 Physiology > 060603 Animal Physiology Systems @ 34%
06 BIOLOGICAL SCIENCES > 0608 Zoology > 060808 Invertebrate Biology @ 33%
SEO Codes: 96 ENVIRONMENT > 9608 Flora, Fauna and Biodiversity > 960899 Flora, Fauna and Biodiversity of Environments not elsewhere classified @ 50%
97 EXPANDING KNOWLEDGE > 970106 Expanding Knowledge in the Biological Sciences @ 50%
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