A scanning electron microscope study of notum structures in some dorid nudibranchs (Gastropoda: Opisthobranchia)

Abstract

Skin structures of nine different species of dorid nudibranchs were examined at the scanning electron microscope and the light microscope levels. From these observations the animals are grouped into three categories.1. Dorids with spicule-supported tubercles carrying a sensory knob (Rostanga rubra, Jorunna tomentosa, Onchidoris sparsa, Onchidoris pusilla).2. Dorids with small sensory papillae set in pits and distributed randomly between projecting spicules (Aegires punctilucens).3. Dorids with tubercles differing in shape from one species to another, invested with numerous spicules but without conspicuous sensory structures. The tips of the tubercles do, however, contain single sensory epithelium cells (Archidoris pseudoargus, Acanthodoris pilosa, Onchidoris muricata, Onchidoris bilamellata).

Morphology and biological roles of spicule networks in Cadlina luteomarginata (Nudibranchia, Doridina)

“…3B,C), which I interpret to be muscle insertion points. Similar muscular attachments to spicules are seen in caryophyllidia of Rostanga arbutus A ngus 1864 and other species, and may allow retraction of these structures, although this has not yet been observed in living specimens (Kress 1981; Foale & Willan 1987). These muscle insertions suggest the intriguing possibility that the role of this spicule network is partly for muscle antagonism.…”

The Anatomy of Respiratory Structures in the Dorid Nudibranchs,Onchidoris BilamellataandArchidoris Pseudoargus, With Details Of The Epidermal Glands

“…Recently Kress (1981) described the dorsal mantle of a number of dorid nudibranchs including light and scanning micrographs of Onchidoris bilamellata and Archidoris pseudoargus. The tubercle structures are described in detail, including the arrangement of the spicular support as well as the distribution of cilia, which are widespread in O. bilamellata and which protrude above surrounding microvilli.…”

“…Herdman (1890) and Rao (1936) give histological details, but do not seriously add to the understanding of the function of dorid gills or their circulation system. While the gill ciliation of bivalves (Atkins, 1938) and prosobranchs (Yonge, 1947) has been thoroughly examined this is not so in dorid nudibranchs and only the ciliation of the notaspid Pleurobranchus membranaceus has been described in any detail (Thompson & Slinn, 1959;Thompson, 1976) and the dorsal mantle of some dorids (Kress, 1981). Much of the general anatomy of opisthobranchs is reviewed by Hoffman (1939).…”

Systematics and phylogeny of the caryophyllidia-bearing dorids (Mollusca, Nudibranchia), with descriptions of a new genus and four new species from Indo-Pacific deep waters

“…However, in these species the spicules are not organized in a circular pattern and there is no a central ciliated tubercle. On the other hand, Kress (1981) showed caryophyllidialooking spiculose tubercles in two species of Onchidoris Blainville, 1816 (phanerobranch dorids). However, according to Foale & Willan (1987), because of the phylogenetic distance between the genus Onchidoris and the caryophyllidia-bearing dorids, any similarities in mantle structures should be attributed to evolutionary convergence.…”

“…Caryophyllidia were first identified, described and named by Labbe (1929Labbe ( , 1930Labbe ( , 1933 from Atlantic cryptobranch dorids of the genera Jorunna Bergh, 1876and Rostanga Bergh, 1879. Kress (1981 studied these organs for the first time using scanning electron microscopy (SEM), and Foale & Willan (1987) invesiigated the structure of caryophyllidia combining of spiculose mantle differentiation within the Doridina.…”