Abstract
Larvae of the two southern hemisphere lamprey genera, Mordacia and Geotria, possess one and two intestinal diverticula, respectively, each originating at the oesophageal-intestinal junction. These diverticula comprise an inner layer of simple columnar epithelium composed solely of zymogen and mucous cells, a middle layer consisting mainly of a blood sinus, and an outer serosa layer covered by a simple squamous epithelium (mesothelium). The inner surface is highly folded only in Mordacia. The secretion of mucus probably protects the epithelium from the effects of digestive enzymes secreted by the zymogen cells and/or bile, which enters the diverticulum at its tip. Unlike the situation in southern hemisphere lampreys, the zymogen cells of the larvae of holarctic lampreys are located in the anterior intestine, a condition considered to be “primitive”. It is thus proposed that intestinal diverticula were developed during the evolution of southern hemisphere lampreys. The relocation of zymogen cells in the diverticula increases the area for these cells, and thus the capacity for the synthesis and secretion of digestive enzymes, particularly in Mordacia where the inner surface is folded.
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References
Barrington EJW (1972) The pancreas and intestine. In: Hardisty MW, Potter IC (eds) The biology of lampreys, vol 2. Academic Press, London, pp 135–169
Berridge MJ, Oschman JL (1972) Transporting epithelia. Academic Press, New York London
Brachet A (1897) Sur le développement du foie et sur le pancréas de l'Ammocoetes. Anat Anz 13:621–636
Cake MH, Potter IC, Power GW, Tajbakhsh M (1992) Digestive enzyme activities and their distribution in the alimentary canal of larvae of the three extant lamprey families. Fish Physiol Biochem 10:1–10
De Ridder C, Jangoux M (1993) The digestive tract of the spantangoid echinoid Echinocardium cordatum (Echinodermata): morphofunctional study. Acta Zool (Stockholm) 74:337–351
Epple A, Brinn JE (1987) The comparative physiology of the pancreatic islets. Springer, Berlin Heidelberg New York
Forey P, Janvier P (1993) Agnathans and the origin of jawed vertebrates. Nature 361:129–134
Hansen SJ, Youson JH (1978) Morphology of the epithelium in the alimentary tract of the larval lamprey, Petromyzon marinus L. J Morphol 155:193–218
Hardisty MW (1982) Lampreys and hagfishes: analysis of cyclostome relationships. In: Hardisty MW, Potter IC (eds) The biology of lampreys, vol 4B. Academic Press, London, pp 165–259
Hilliard RW, Potter IC (1988) Morphology of the exocrine pancreas of the southern hemisphere lamprey, Geotria australis, and changes during metamorphosis. J Morphol 197:33–52
Hubbs CL (1952) Antitropical distribution of fishes and other organisms. Proc Pacific Sci Congress 7:324–329
Hubbs CL, Potter IC (1971) Distribution, phylogeny and taxonomy. In: Hardisty MW, Potter IC (eds) The biology of lampreys, vol 1. Academic Press, London, pp 1–65
Luppa H (1964) Histologische und topochemische Untersuchungen am Epithel des Oesophagus und des Mitteldarmes von Lampetra planeri (Bloch). Z Mikrosk Anat Forsch 71:85–113
Luppa H, Ermisch A (1967) Untersuchungen zur Struktur und Funktion des exokrinen Pankreas von Neunaugen. Morphol Jb 110:245–269
Maskell FG (1930) On the New Zealand lamprey, Geotria australis, Gray. Part 2. On the mid-gut diverticula, the bile duct and the problem of the pancreas in the ammocoetes stage. Trans R Soc New Zealand 61:478–497
Moore JW, Mallatt JM (1980) Feeding of larval lamprey. Can J Fish Aquatic Sci 37:1658–1664
Palade GE (1975) Intracellular aspects of the process of protein secretion. Science 189:347–358
Potter IC (1970) The life cycles and ecology of Australian lampreys of the genus Mordacia. J Zool 161:487–511
Potter IC (1980a) The Petromyzoniformes with particular reference to paired species. Can J Fish Aquatic Sci 37:1595–1615
Potter IC (1980b) Ecology of larval and metamorphosing lampreys. Can J Fish Aquatic Sci 37:1614–1657
Potter IC (1986) The distinctive characters of southern hemisphere lampreys (Geotriidae and Mordaciidae). In: Uyeno T, Arai R, Taniuchi T, Matsuura K (eds) Proceedings of the Second International Conference on Indo-Pacific Fishes. Ichthyological Society of Japan, Tokyo, pp 9–19
Potter IC, Hilliard RW (1986) Growth and the average duration of larval life in the southern hemisphere lamprey, Geotria australis Gray. Experientia 42:1170–1173
Potter IC, Hilliard RW (1987) A proposal for the functional and phylogenetic significance of differences in the dentition of lampreys (Agnatha: Petromyzontiformes). J Zool 212:713–737
Strahan R, Maclean JL (1969) A pancreas-like organ in the larva of the lamprey, Mordacia mordax. Aust J Sci 32:54–55
Welsch U (1975) The fine structure of the pharynx, cyrtopodocytes and digestive caecum of Amphioxus (Branchiostoma lanceolatum). Symp Zool Soc Lond 36:17–41
Youson JH (1983) The alimentary canal. In: Hardisty MW, Potter IC (eds) The biology of lampreys, vol 3. Academic Press, London, pp 95–189
Youson JH, Potter IC (1993) An immunohistochemical study of enteropancreatic endocrine cells in larvae and juveniles of the southern hemisphere lampreys, Geotria australis and Mordacia mordax. Gen Comp Endocrinol 92:151–167
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Bartels, H., Potter, I.C. Structural organization and epithelial cell types of the intestinal diverticula (protopancreas) of ammocoetes of southern hemisphere lampreys: functional and phylogenetic implications. Cell Tissue Res 280, 313–324 (1995). https://doi.org/10.1007/BF00307804
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DOI: https://doi.org/10.1007/BF00307804