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1.
A new species of dicyemid mesozoan is described from Benthoctopus sibiricus Loyning, 1930, collected in the eastern Chukchi Sea. Dicyemennea chukchiense n. sp. is a medium species that reaches about 2,000 μm in length; it lives in folds of the renal appendages. The vermiform stages are characterized in having 23 peripheral cells, a conical calotte, and an axial cell that extends to the base of the propolar cells. An anterior abortive axial cell is present in vermiform embryos. Infusoriform embryos consist of 37 cells; a single nucleus is present in each urn cell and the refringent bodies are solid. This is the first dicyemid described from the Arctic waters.  相似文献   

2.
A new species of dicyemid mesozoan is described from Octopus hubbsorum Berry, 1953, collected in the south of Bahia de La Paz, Baja California Sur, México. Dicyema guaycurense n. sp. is a medium-size species that reaches about 1,600 μm in length. It occurs in folds of the renal appendages. The vermiform stages are characterized as having 22 peripheral cells, a conical calotte, and an axial cell that extends to the base of the propolar cells. Infusoriform embryos consist of 39 cells; 1 nucleus is present in each urn cell and the refringent bodies are solid. This is the first of a dicyemid species from a host collected in the Gulf of California.  相似文献   

3.
4.
Two species of dicyemid mesozoan are redescribed from Rossia pacifica Berry, 1911, collected off Iwase in Toyama Bay, Honshu, Japan. Dicyemennea brevicephaloides Bogolepova-Dobrokhotova, 1962, is a large species that reaches about 4,000 microm in length. This species attaches to the surface of the branchial heart appendages. The vermiform stages are characterized as having 23 peripheral cells, a disc-shaped calotte, and an axial cell that extends to the propolar cells. An anterior abortive axial cell is absent in vermiform embryos. Infusoriform embryos consist of 35 cells; a single nucleus is present in each urn cell and the refringent bodies are absent. Dicyemennea rossiae Bogolepova-Dobrokhotova, 1962, is a medium species that reaches about 2000 microm in length. This species lives in folds of the renal appendages. The vermiform stages are characterized as having 29-34 peripheral cells, a conical calotte, and an axial cell that extends to the middle of the metapolar cells. An anterior abortive axial cell is present in vermiform embryos. Infusoriform embryos consist of 39 cells; 2 nuclei are present in each urn cell and the refringent bodies are solid.  相似文献   

5.
Three new species of dicyemid mesozoan are described from Octopus sasakii Taki, 1942, collected from Tosa Bay and Kii Strait in Japan. Dicyema shimantoense n. sp. is a medium-size species that reaches about 3,000 microm in length, and lives in folds of the renal appendages. The vermiform stages are characterized by having 22 peripheral cells, a conical calotte, and an axial cell that extends to the base of the propolar cells. Infusoriform embryos consist of 37 cells; a single nucleus is present in each urn cell, and the refringent bodies are solid. Dicyema codonocephalum n. sp. is also a medium-size species that reaches about 2,000 microm in length. It too lives in folds of the renal appendages. The vermiform stages are characterized by having 17-22 peripheral cells, an elongated calotte, and an axial cell that extends to the middle of propolar cells. Infusoriform embryos consist of 37 cells; a single nucleus is present in each urn cell, and the refringent bodies are solid. Dicyemennea pileum n. sp. is a medium species that reaches about 2,000 microm in length. It attaches to the surface of the renal appendages. The vermiform stages are characterized by having 23 peripheral cells, a disc-shaped calotte, and an axial cell that extends to the propolar cells. An anterior abortive axial cell is absent in vermiform embryos. Infusoriform embryos consist of 38 cells; 2 nuclei are present in each urn cell, and the refringent bodies are liquid. These are the first dicyemids to be described from Octopus sasakii.  相似文献   

6.
Three new species of dicyemid mesozoans are described from the renal appendages of Amphioctopus fangsiao, collected off Akashi, in Harima Nada, and from Osaka Bay. Dicyema akashiense n. sp. is a small species that reaches about 900 microm in length. The vermiform stages are characterized as having 15-17 peripheral cells, a conical calotte, and an axial cell that extends to the base of the metapolar cells. Infusoriform embryos consist of 37 cells; two nuclei are present in each urn cell, and the refringent bodies are solid. Dicyema helocephalum n. sp. is a small species that reaches about 800 microm in length. The vermiform stages are characterized as having 22 peripheral cells, a disc-shaped calotte, and an axial cell that extends to the base of the propolar cells. Infusoriform embryos consist of 37 cells; a single nucleus is present in each urn cell, and the refringent bodies are solid. Dicyema awajiense n. sp. is a small species that reaches about 300 microm in length. The vermiform stages are characterized as having 22 peripheral cells, a conical calotte, and an axial cell that extends to the middle of the propolar cells. Infusoriform embryos consist of 37 cells; a single nucleus is present in each urn cell, and the refringent bodies are solid. In A. fangsiao various occurrence patterns of dicyemid species were observed, including instances where different dicyemid species were found in the renal appendage on each side. This suggests that dicyemids infect each renal appendage independently. The prevalence, reproductive traits, calotte shapes, and co-occurrence patterns of dicyemids are briefly discussed.  相似文献   

7.
We describe here two new species of oegopsid squids. The first is an Asperoteuthis (Chiroteuthidae), and it is based on 18 specimens. This new species has sucker dentition and a funnel–mantle locking apparatus that are unique within the genus. The second new species is a Promachoteuthis (Promachoteuthidae), and is based on a unique specimen. This new species has tentacle ornamentation which is unique within the genus. We also describe a new genus and a new species of sepioid squid in the subfamily Heteroteuthinae (Sepiolidae) and it is based on four specimens. This new genus and species exhibits unique modifications of the arms in males.  相似文献   

8.
Coleoids are part of the Cephalopoda class, which occupy an important position in most oceans both at an ecological level and at a commercial level. Nevertheless, some coleoid species are difficult to distinguish with traditional morphological identification in cases when specimens are heavily damaged during collection or when closely related taxa are existent. As a useful tool for rapid species assignment, DNA barcoding may offer significant potential for coleoid identification. Here, we used two mitochondrial fragments, cytochrome c oxidase I and the large ribosomal subunit (16S rRNA), to assess whether 34 coleoids accounting for about one-third of the Chinese coleoid fauna could be identified by DNA barcoding technique. The pairwise intra- and interspecific distances were assessed, and relationships among species were estimated by NJ and bayesian analyses. High levels of genetic differentiation within Loliolus beka led to an overlap between intra- and interspecific distances. All remaining species forming well-differentiated clades in the NJ and bayesian trees were identical for both fragments. Loliolus beka possessed two mitochondrial lineages with high levels of intraspecific distances, suggesting the occurrence of cryptic species. This study confirms the efficacy of DNA barcoding for identifying species as well as discovering cryptic diversity of Chinese coleoids. It also lays a foundation for other ecological and biological studies of Coleoidea.  相似文献   

9.
10.
The statocyst shows a remarkable combination of features of decapods and octopods confirming that Vampyroteuthis is a relic somewhere near the ancestor of both groups. The lining of the statocyst separates from the outer wall, forming an inner sac, filled with endolymph, surrounded by perilymph. This is the condition found in octopods, never in decapods. The macula is partly divided into a macula princeps and macula neglecta, as in decapods but never in octopods. There are numerous statoconia, but no large statolith has been seen. The crista has four parts as in decapods, but they are not sharply separated. There are numerous small anticristae, with the general form found in decapods, differentiated into pegs and hooks.
The wall of the inner sac contains numerous hair cells. These hairs protrude between the epithelial cells. The bases of the cells are drawn out into fine processes, presumably some dendritic and some axonal. There is thus a plexus of nerve fibres all over the wall, communicating with the crista nerve.
There is a very large posterior sac of unknown function, lying behind the crista. It contains only one large anticrista and the opening of Kölliker's canal, which is very large.  相似文献   

11.
Marion  Nixon  Peter  Boyle 《Journal of Zoology》1982,196(4):439-444
Eledone drills holes in the carapace of crustaceans with the tooth-covered salivary complex in conjunction with salivary secretions.  相似文献   

12.
A new species of dicyemid mesozoan is described from a cuttlefish Sepia latimanus Quoy and Gaimard collected off Nago, Naha and Onnason, Okinawa Islands, Ryukyu Islands, Japan. Dicyemennea ryukyuense n. sp. is a large species that reaches about 5 mm in length. The vermiform stage is characterised by 23 peripheral cells, a conical calotte and an axial cell that extends to the base of the propolar cells. The infusoriform embryo consists of 37 cells; two nuclei are present in each urn cell and the refringent bodies are solid. In the type of reproductive strategy, rhombogens of D. ryukyuense form a small number of infusorigens and produce a relatively large number of gametes per infusorigen. In the family Dicyemidae, Dicyemennea Whitman, 1883 is the largest group after Dicyema von Kölliker, 1849. Other dicyemid species, including those belonging to Dicyema, were not detected. Dicyemids have never previously been detected in cephalopods living on corals and rocks off the Ryukyu Islands, even though they are benthonic in habitat. This is the first report of a dicyemid mesozoan from S. latimanus and also from off the Ryukyu Islands. S. latimanus inhabits coral reefs, often swimming over the coral but usually lying on the sandy bottom. Dicyemids cannot possibly infect cephalopods which live exclusively over coral and rock.  相似文献   

13.
A species of dicyemid mesozoan is redescribed from the giant Pacific octopus, Enteroctopus dofleini (Wülker, 1910), collected off Iwase in Toyama Bay, Honshu, Japan. Dicyemennea nouveli McConnaughey, 1959, is a large species that reaches about 12,000 microm in length. This species lives in folds of the renal appendages. The vermiform stages are characterized as having 30-41 peripheral cells, a conical calotte, and an axial cell that extends to the middle of the metapolar cells. An anterior abortive axial cell is present in vermiform embryos. Full-grown vermiform embryos have as many as 4 agametes. Infusoriform embryos consist of 39 cells; 2 nuclei are present in each urn cell and the refringent bodies are solid.  相似文献   

14.
Nautilusr pompilius and N. macromphalus shells show, under cathodoluminescence microscopy. a zoned luminescence of yellow to green for the former and blue to blue-green for the latter. Cathodoluminescence results from fluctuations in the amount of manganese present in the aragonite. There is a relationship between this phenomenon and growth lines. Luminescence intensity increases with ontogeny. Variations in the metabolic activity appear to be linked with the manganese content of the shell. Environmental factors may have an effect by way of their repercussion on the metabolic activity of Nautilus . The Mn2+ amount may be influenced by the physico-chemical pattern of the surrounding water but it appears also to be controlled at the species level.  相似文献   

15.
Octopus vulgaris drills holes in the shells of a variety of molluscs. The walls of the cavities drilled exhibit dissolution of mineral and organic material. The features which characterize the cavities have been described. The composition and structure of the shell itself is important in determining the size, shape and form of the cavity drilled, and not the size of the octopus. Capture, drilling the shell, and eating the occupant may take less than one hour.  相似文献   

16.
The ocular photophore of Bathothauma emits light. The presumed photogenic tissue is cellular and contains a mass of highly organized crystalloids. One of its surface abuts against a fibrous system that probably acts as a light guide. The rest of the organ is surrounded by a pigment screen of modified iridophores.  相似文献   

17.
In the larvae of some cranchiid squids the eyes are carried sideways on long stalks and also possess a presumed luminous organ. The structure of this organ is described but the only sign of light producing tissues is some possible luminescent bacteria. The stalked eye may be connected with plankton feeding at great depths, perhaps improving distance judgement. The older animals of these species carry a different form of luminous organ.  相似文献   

18.
Tritoniid sea slugs (Mollusca, Gastropoda, Opisthobranchia) are reported for the first time from Bouvet Island. Tritonia dantarti sp. n. shows morphological and anatomical differences with regard to the two previously known tritoniids reported from Antarctica and Sub-Antarctica, Tritonia vorax (Odhner 1926) and Tritonia challengeriana Bergh, 1884. Regarding the external morphology, T. dantarti sp. n. is characterized by a very bright orange coloration in the dorsum, white dorsal crests, highly ramified dendritic gills (the largest vertically orientated and the rest laterally orientated), and a quadrangular cross section. The radula presents very long, thin lateral teeth and the jaws present mainly unicuspidate, striated denticles. The seminal receptacle is large, pear-shaped and its grey pigmentation differs from the rest of the genital system. The Antarctic species T. challengeriana was also found in waters off Bouvet Island, while the Subantarctic species T. vorax was not found.  相似文献   

19.
Dicyemennea canadensis n. sp. is described from a bathyal octopus collected off Canada in the Bay of Fundy. The dicyemid is a small species that rarely exceeds 600 microm in length. The vermiform stages are further characterized as having 17-23 peripheral cells, a conical-shaped calotte, an axial cell that extends to the base of the propoplar cells, and no abortive axial cells. Infusoriform embryos consist of 37 cells. There is 1 nucleus in each urn cell, and refringent bodies are absent. This is the first dicyemid to be described from the cephalopod Bathypolypus arcticus (Prosch. 1847), and the first dicyemid reported from Canada. In addition, it is the first species of Dicyemennea from the northwestern Atlantic Ocean to be described.  相似文献   

20.
Taxonomic accounts of octopodids frequently describe the spermatophore, the penis that releases the spermatophore from the internal organs, and the ligula and calamus that transfer it to a female. To explore relationships among these male features and body size, this study applies principal components analysis to data from 43 species of the family Octopodidae, or benthic octopuses. Covariation in penis and mantle length opposed by covariation in ligula and calamus lengths forms primary shape variation. Secondary shape variation is due to opposing variation between ligula and calamus lengths. Primary shape variation is greatest among shallow-water species. The calami and ligulae of diurnal and crepuscular shallow-water species are short compared to those of nocturnal shallow-water species. Because these structures contain heterogeneous collagen arrays and lack camouflaging chromatophore organs, they are white. Diurnal and crepuscular octopus species may minimize their lengths due to selection imposed by visual predators. Secondary shape variation is greater in deep-sea and high-latitude octopuses. Members of Voss's Eledoninae (except Eledone) and Graneledoninae and two species of Benthoctopus have exceptionally long calami and comparatively short ligulae; these lengths vary among members of the Bathypolypodinae. Variation in spermatophore length is independent of the structures considered.  相似文献   

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