Rol n e (62 Ergebnisse)

New taxon: Brocchinia canariensis n. sp. 7 pp., 13 figs, br. gr. 8.

5 pp., 10 figs, br. gr. 8.

After some land observations, it is recorded that the gastropod Iselica anomala is a parasitic of the bivalve Atrina rigida. 5 pp., 5 figs, br. gr. 8.

2 pp., 5 figs, br. gr. 8.

The species of the genus Assiminea from the occidental African coast are studied, and comparisons with those previously known are presented. In the absence of definitive proof. it is assumed that Assiminea hessei O. Boettger, 1887 is applicable to the Angolan populations. Five new species are described. New taxa: Assiminea principensis n. sp., Assiminea saotomensis n. sp., Assiminea occulta n. sp., Assiminea senegalensis n. sp., Assiminea moroccoensis n. sp. 19 pp., 11 figs, 4.…

12 pp., 34 figs, 4.

New taxa: Miralda temperata n. sp., Miralda superba n. sp. 8 pp., 7 figs, 8.

New taxon: Lirularia antoniae spec. nov. 7 pp., 9 figs, 8.

A new species of the genus Vitrinella, Vitrinella kaykayae spec. nov., from Concepci?n, Chile, is described. It represents the first record of a species of this genus for that coast. The new species is compared with other species morphologically similar. 6 pp., 7 figs, gr. 8.

New taxon: Eatonina martae n. sp. 6 pp., 4 figs, gr. 8.

A new species of Cerithiopsis, Cerithiopsis krisbergi sp. nov., from Florida, USA, is described. The new species is compared with others of brown color previously known from the Caribbean Sea. Shell, protoconch, radula and operculum are figured. 5 pp., 14 figs, gr. 8.

A new species of Dizoniopsis, Dizoniopsis apexclarus sp. nov., from Principe, Sao Tom? and Annobon is described showing differences with other similar species. 4 pp., 10 figs, gr. 8.

Columbella minor Scacchi, 1836 is revised in the genus Mitrella Risso, 1826, on the basis of its original description and figure, and of the study of shell material from Mediterranean and the nearby Atlantic. A neotype of C. minor is designated. C. minor takes priority on the older name Mangelia vitrea Risso, 1826 on the basis of the article 23.9 of the Code of Zoological Nomenclature. The variability of the shell morphology, of the shell decoration and of the animal chromatism is discussed. A sibling species ranging from Alboran Island to Northern Senegal is described as Mitrella hernandezi sp. nov. Its principal diagnostic features lie in a large white pupoid protoconch instead of a small brown pointed one in M. minor, and in a thin lattice-patterned periostracum instead of a thick coarsely wrinckled on in M. minor. 15 pp., 43 figs, gr. 8.…

A new species Olivella (Olivella) arionata is described from shallow waters off southern Brazil. It is recognitable by characters of colour, subsutural bnd, fasciole, and the lack of an operculum. The pillar structure of young forms shows si,ilarities to subgenus Olivina. 1+3 pp., 2+6 figs, 4.

The species of Metaxia Monterosato, 1844 found in Cuba are shown. The shell and the protoconch of each one are described and figured. M. taeniolata Dall, 1889 is considered a valid species. Also it is described a new species: M. espinosai n. sp. 8 pp., 10 figs, gr. 8.

The species of the genus Amphithalamus in Cuba Island are studied. Three new species, i.e. Amphitalamus rauli n. sp., A. albus and A. niger n. sp., are described. Moreover Amphithalamus vallei Aguayo & Jaume, 1947, the only known species in the area, is redescribed. 11 pp., 15 figs, gr. 8.

A new species in the genus Lodderena (Gastropoda: Skeneidae), Lodderena bunnelli n. sp., is described from Abaco (Bahamas). The new species is compared to L. ornata (Olsson & McGinty, 1958). 6 pp., 12 figs, gr. 8.

Three new species of the genus Alvania collected in Sao Tom? Island are described. The new species are compared with others of similar morphology from the African coast. Some characters, usually considered typical of the genus Manzonia are commented on; these appear in some species here included in the genus Alvania. The latter genus probably constitutes a kind of catchall for many other valid genera that are at present inadequately defined. 10 pp., 23 figs, gr. 8.…

A new species, Onoba nunezi spec. nov., probably endemic of the Canary Islands is described. It is compared with other species of the genus and with Manzonia vigoensis, which is rather similar and with which was previously confused. At the same time a shell of Manzonia vigoensis from the Canary Islands is shown. Some remarks on this species and its geographical range and distribution are given. 7 pp., 12 figs, gr. 8.…

Four species, collected in the Cape Verde Islands, are described as new and asigned to the genus Euthria M. E. Gray, 1830. The new species are compared with other taxa from the Mediterranean Sea and the Cape Verde Archipelago. The genera Euthria, and Buccinulum are compared and the significance of the differences between them is discussed, leading to the conclusion that both genera are valid and should be kept separated. 13 pp., 31 col. figs, gr. 8.…

12 pp., 5 col. pls, stapled 4.

Two new species of Nassariidae (Gastropoda: Buccinacea) from West Africa are described, figured, and compared with the most similar one. Adinopsis skoogi Odhner, 1923, with some comments on this species. Adinopsis being an invalid genus name is replaced by Adinassa n. nom., in which the new species are placed. New taxa: Adinassa barcai n. sp., Adinassa parrulai n. sp. 10 pp., 3 color plates, 4.…

The second species of the genus Plagyostila is described. It was found in Dakar, Senegal. Comparison of the shell characters of the new species with those of the type species Plagyostila asturiana are made. New taxon: Plagyostila senegalensis n. sp. 4 pp., 5 figs, gr. 8.

A new species of the genus Bela Leach in Gray, 1847, from West Africa, is described and figured, and compared with the most similar one, Bela nuperrima (Tiberi, 1855). New taxon: Bela schoenherri n. sp. 8 pp., 3 plates, 4.

Fusinus albacarinoides sp. nov. is described from south Portugal, off the Algarve coast in 14-22 m depth. It is characterized by having a small red-brown to dark brown shell ornamented with a conspicuous white band at the periphery, with a rough shell surface, an elongate slender spire and a short siphonal canal. The new species is distinguished by its shell morphology and the soft parts from all other eastern Atlantic and Mediterranean Fusinus and is compared to a few of them. 11 pp., 30 figs, gr. 8.…

Alvania gascoignei spec. nov. from Annob?n is described as new for science. It is compared with other species of this genus in eastern Africa. 4 pp., 4 figs, gr. 8.

Zospeum percostulatum sp. n. from Cueva de La Herrer?a (Llanes, Asturias) is described. It is characterized by a relatively large shell (1.4?1.8 mm height), conical, with ovate aperture, continuous peristome and thickened parietal callus; shell costulate except two first whorls; without any sort of inner formations. It is the first clearly costulate Iberian species, filling a morphological gap in the Iberian clade, and the largest species from the Cantabrian region, being the first species described from Asturias. 14 pp., 6 figs, gr. 8.…

The genetic structure of two sibling and sympatric species of the genus Littorina was compared using allozymic loci. The two species are biologically and ecologically well-known and mostly show similar life history characteristics. Three populations of Littorina mariae Sacchi & Rastelli and Littorina obstusata (L.) were studied in the Muros-Noya Ria (Galicia, NW Spain). In addition, four microgeographical subsamples taken from one of the populations were analysed for each species. Age, sex and genotypes for nine polymorphic loci were studied in 1250 snails of both species. L. mariae showed larger genetic population subdivision and lower heterozygosity levels for the loci studied than did L. obtusata. Heterozygote deficiencies were found in only a few cases in natural populations of both species, usually affecting the Lap-1 locus. No significant genetic differences among age or sex classes were found. These results may be explained by the lower effective population size in L. mariae than in L. obtusata. Known differences between these species in generation interval and population density during the winter can cause the different effective population sizes suggested. These life history characteristics appear to provide the most likely explanations for the differences in genetic differentiation and heterozygosity between the two species. A previously unknown L. mariae morph from exposed shores is tentatively suggested to be conspecific. 9 pp., 2 figs, 4 tabs, gr. 8.…

Galician exposed shore populations of the direct developing periwinkle Littorina saxatilis are strikingly polymorphic, with an ornamented and banded upper shore form and a smooth and unbanded lower shore form. Intermediates between the two pure forms occur in a narrow mid shore zone together with the parental forms. We have previously shown that the two pure forms share the same gene pool but that mating between them is non-random. This is due to a non-random microdistribution in the zone of overlap, and also to assortative mating. In this study we present data which show that intermediate (hybrid) females mate less often than pure females in micropatches dominated by either of the pure forms, but not in micropatches in which the two pure forms are equally common. Thus, sexual fitness in intermediate females depends on the frequency of both pure morphs. Furthermore, sexual selection against intermediate females also varies with the densities of snails within each micro patch. The biological mechanisms which may explain this particular reduction of female hybrid fitness are discussed. Assortative mating between the pure morphs is sometimes almost complete, while both morphs do not mate the intermediates assortatively. In the light of this, sexual selection against intermediate females may contribute considerably to restrict gene flow between the pure forms. 6 pp., 2 tabs, 4.…

2 pp. + 1 pl. gr. 8.