02856naa a2200145 a 450000100080000000500110000800800410001910000160006024501060007626000090018252021540019170000220234570000220236777303210238913148022008-09-15       2008    bl uuuu     u00u1 u    #d1 aMÉNDEZ, J.  aMorphological and structural aspects of the earthworm calciferous gland and its calcareous secretion.  c2008  aThe oesophageal glands of earthworms are commonly referred as calciferous glands and they are present in all species of the family Lumbricidae. Most studies have mainly focused on the well-known Lumbricus terrestris, however many structural aspects are still unknown for the majority of the species included in the family and the significance of their secretions remains uncertain. In this study we provide new insights into the morphology and ultraestructure of several earthworm species belonging to three genera (Allolobophora, Dendrobaena and Octolasion) collected from different locations in Europe. Earthworms were hand-sorted in the field and taken back to the laboratory for removal of the glands by dissection. The morphological studies of the mineral phases involved in the calcareous secretions were analysed by field emission scanning electron microscopy (FE-SEM) of the air dried frozen sections. Results showed that the anatomy of the glands of these three genera falls into three types: (i) pouches and oesophageal enlargements present (Octolasion), pouches present but no enlargements (Allolobophora), pouches absent but enlargements present (Dendrobaena). Calcium secretion usually appears initially to be a ?milky fluid? and in those species with pouches the calcium carbonate crystals aggregate resulting in bigger concretions of different sizes. The morphological characterisation of the mineral secreetion using FE-SEM showed that the glandular segments contained spherulites usually packing the interlamellae spaces. These spherulithic deposits mainly consisted of ovoid to spherical particles varying in size. In contrast, all the morphologies detected in the solid concretions stored in the pouches could be classified into spherulithic, mulberry-like aggregates and rhombohedral crystals. Coalescence between two or more spheres was occasionally observed leading to the formation of larger aggregates, and possibly to the ultimate formation of rhombohedral calcite crystals. These results evidence that the differences in the anatomy of the gland determine the morphology of the calcareous secretion among different species.1 aALVAREZ-OTERO, R.1 aBRIONES, M. J. I.  tIn: INTERNATIONAL COLLOQUIUM ON SOIL ZOOLOGY, 15; INTERNATIONAL COLLOQUIUM ON APTERYGOTA, 12., 2008, Curitiba. Biodiversity, conservation and sustainabele management of soil animal: abstracts. Colombo: Embrapa Florestas. Editors: George Gardner Brown; Klaus Dieter Sautter; Renato Marques; Amarildo Pasini. 1 CD-ROM.