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Coriocella and the Worms: First Record of Scale-Worm Asterophilia cf. culcitae Ectosymbiotic on a Mollusc
Full text linkSpecies of the mollusc genus Coriocella (Velutinidae) produce defensive biocompounds, making them potentially valuable hosts for other marine invertebrates. However, so far, only two instances of crustaceans ectosymbiotic on their mantle have been reported. This is the first observation, made in New Caledonia, of a pair of scale-worms identified as Asterophilia cf. culcitae (Polynoidae) hiding themselves on the mantle of Coriocella cf. tongana. This finding represents the first evidence of a symbiotic interaction between these two groups, expanding the association range for both taxa, and providing new insight into their, mostly unknown, ecology
The Dancing Marsenia: The First Record of a Swimming Velutinid Mollusc
Full text linkAmong gastropods, the ability to swim has developed independently several times, mostly among Heterobranchia. Only a few species of Caenogastropoda are known to have swimming adults. Velutinidae Gray, 1840, is a family of caenogastropods with a fragile shell enclosed by the mantle. The adults of this family are benthic and ectoparasites of ascidians. Here, we present the first recorded instance of a swimming velutinid, Marsenia cf. gemma, filmed in New Caledonia. The swim propulsion method was based on the movement of the snail’s foot, which followed a ∞-shaped curve. This first report changes our perspective on the biology of this family, unexpectedly placing it within the restricted group of swimming caenogastropods
Neither slugs nor snails: a molecular reappraisal of the gastropod family Velutinidae
Full text linkFassio, Giulia, Stefani, Matteo, Russini, Valeria, Buge, Barbara, Bouchet, Philippe, Treneman, Nancy, Malaquias, Manuel António E., Schiaparelli, Stefano, Modica, Maria Vittoria, Oliverio, Marco (2023): Neither slugs nor snails: a molecular reappraisal of the gastropod family Velutinidae. Zoological Journal of the Linnean Society 197 (4): 924-964, DOI: 10.1093/zoolinnean/zlac091, URL: http://dx.doi.org/10.1093/zoolinnean/zlac09
FIG. 2 in Three new species of Raphitoma Bellardi, 1847 (Mollusca, Gastropoda, Raphitomidae) from Croatian waters (NE Adriatic Sea)
No full textFIG. 2. — Measurements taken on protoconch of Raphitoma pusaterii Prkić & Giannuzzi-Savelli n. sp. Diameter of nucleus (D nuc. = 105 µm), diameter of first half-whorl (D ½ = 159 µm), diameter of first whorl (D 1 = 190 µm), maximum diameter (Max. D = 440 µm), number of whorls (PW = 3.6), number of whorls of protoconch 1 (PW 1 = 1.1). Scale bar: 200 µm.Published as part of Prkić, Jakov, Giannuzzi-Savelli, Riccardo, Pusateri, Francesco, Russini, Valeria, Fassio, Giulia & Oliverio, Marco, 2020, Three new species of Raphitoma Bellardi, 1847 (Mollusca, Gastropoda, Raphitomidae) from Croatian waters (NE Adriatic Sea), pp. 215-237 in Zoosystema 42 (16) on page 218, DOI: 10.5252/zoosystema2020v42a16, http://zenodo.org/record/387230
Raphitoma Bellardi 1847
No full textGenus Raphitoma Bellardi, 1847 Raphitoma Bellardi, 1847: 84. Homotoma Bellardi, 1875: 22, non Homotoma Guérin-Méneville, 1844 (type species Murex textile Brocchi, 1814 by subsequent designation [Fischer 1883]). Cordieria Monterosato, 1884: 131, non Cordieria Rouault, 1848 (type species Murex reticulatus Brocchi, 1814, by subsequent designation [Crosse 1885]). Philbertia Monterosato, 1884: 132 (type species Pleurotoma philberti Michaud, 1829 by subsequent designation [Crosse 1885]). Peratoma Harris & Burrows, 1891: 113 (nomen novum pro Homotoma Bellardi, 1875, non Homotoma Guérin-Méneville, 1844). TYPE SPECIES. — Pleurotoma hystrix Cristofori & Jan, 1832 (nomen nudum, made available by Bellardi 1847 as “ Pleurotoma histrix Jan. ”) by subsequent designation (Monterosato 1872: 54).Published as part of Prkić, Jakov, Giannuzzi-Savelli, Riccardo, Pusateri, Francesco, Russini, Valeria, Fassio, Giulia & Oliverio, Marco, 2020, Three new species of Raphitoma Bellardi, 1847 (Mollusca, Gastropoda, Raphitomidae) from Croatian waters (NE Adriatic Sea), pp. 215-237 in Zoosystema 42 (16) on page 218, DOI: 10.5252/zoosystema2020v42a16, http://zenodo.org/record/387230
FIG. 21. — A in Revision of Mediterranean and NE Atlantic Raphitomidae (Gastropoda, Conoidea) 8: The genus Leufroyia Monterosato, 1884
No full textFIG. 21. — A, Pleurotoma inflata De Cristofori & Jan, 1832, Lectotype, (MCSNM i 4296) Tabiano (Parma) Piacentian (Pliocene), h. 15.3 mm (after Pinna & Spezia, 1978, pl. 40); B, P. inflata, Ficarazzi (Palermo) (Lower Pleistocene), h. 18.9 mm (NMW, 12930), erroneously identified by Monterosato as Leufroyia volutella; C, P. inflata, Monte Pellegrino (Palermo) (Plio-Pleistocene) (MCZR-M-16706), h. 23.9 mm; D, Pleurotoma volutella Kiener, 1839, original drawings by Kiener, h. 25.4 mm; E, P. volutella, Ficarazzi (Palermo) (Lower Pleistocene), h. 21.5 mm; F, Pleurotoma cf. volutella Monte Pellegrino (Palermo) (Pliocene), h. 25.8 mm.Published as part of Giannuzzi-Savelli, Riccardo, Pusateri, Francesco, Prkić, Jakov, Bartolini, Stefano, Russini, Valeria, Fassio, Giulia & Oliverio, Marco, 2020, Revision of Mediterranean and NE Atlantic Raphitomidae (Gastropoda, Conoidea) 8: The genus Leufroyia Monterosato, 1884, pp. 433-473 in Zoosystema 42 (22) on page 464, DOI: 10.5252/zoosystema2020v42a22, http://zenodo.org/record/400287
FIG. 2 in Revision of Mediterranean and NE Atlantic Raphitomidae (Gastropoda, Conoidea) 8: The genus Leufroyia Monterosato, 1884
No full textFIG. 2. — Relationships and genetic divergence among species of Raphitomidae Bellardi, 1875. A, Bayesian topology on the COI alignment. Numbers at nodes are posterior probabilities after a Bayesian analysis, and bootstrap supports after Maximum likelihood analysis on 1000 pseudoreplicates; only values higher than 75% bootstrap support and 95% posterior probability are reported. The boxes comprise the species hypotheses as defined by the ABGD analysis. B, Distribution of the pairwise genetic distances (K2p) among the COI sequences (black bars on the left, intraspecific comparisons; on the right, interspecific comparisons).Published as part of Giannuzzi-Savelli, Riccardo, Pusateri, Francesco, Prkić, Jakov, Bartolini, Stefano, Russini, Valeria, Fassio, Giulia & Oliverio, Marco, 2020, Revision of Mediterranean and NE Atlantic Raphitomidae (Gastropoda, Conoidea) 8: The genus Leufroyia Monterosato, 1884, pp. 433-473 in Zoosystema 42 (22) on page 436, DOI: 10.5252/zoosystema2020v42a22, http://zenodo.org/record/400287
Larval strategies and connectivity in marine gastropods
No full textConnectivity is defined as the property and degree of interchange between populations. In the marine environment, this property is strongly influenced by the strategy of larval development. This is especially true for benthic organisms, which have a sessile adult lifestyle and can rely only on the larval phase for dispersal. Larval developments can be classified into two main types: planktotrophic and non-planktotrophic (mostly lecithothrophic) development. It is reasonable to hypothesize that different larval developments produce different patterns of connectivity. Several hypotheses can be tested on the relationship between genetic connectivity and duration of the larval phase: (i) isolation by distance occurs in species with non- planktotrophic development and not in species with planktotrophic development; (ii) genetic diversity and variance distribution are different in the two classes: low diversity and larger intrapopulation variance with planktotrophic development; high diversity and larger interpopulation variance with lecithothrophic development; (iii) different phylogeographic structure: phylogenetic trees not geographically structured with planktotrophic development and geographically structured with lecithothrophic development; (iv) different haplotypes networks: few haplotypes shared by most with planktotrophic development, and more haplotypes shared by geographically related groups with the lecithothrophic development. We first positively tested these hypotheses on literature datasets of three species of the genus Crepidula with different larval developments. Then we applied the same approaches on three original case studies: the sibling species Columbella rustica (Mediterranean, lecithotrophic) and C. adansoni (Atlantic, planktotrophic); and the Antarctic Capulus subcompressus and Marseniopsis spp. (both planktotrophic). All analyses positively tested the hypotheses of relationship between genetic connectivity and duration of the larval phase. Noteworthy, in Antarctica the planktotrophic development is usually severely counterselected, due the strictly seasonal presence of phytoplankton. Capulus subcompressus is the only Antarctic capulid with a planktotrophic development, and the genetics analyses confirmed the high connectivity patterns among populations as well as for species of the genus Marseniopsis
Figure 2 in High cryptic diversity in the kleptoparasitic genus Hyalorisia Dall, 1889 (Littorinimorpha: Capulidae) with the description of nine new species from the Indo-West Pacific
No full textFigure 2. Phylogenetic relationships of the genus Hyalorisia (Bayesian tree based on the combined dataset). Boxes indicate the three lineages, A, B and C, of Hyalorisia. Numbers at nodes are PP and UFb branch support values, respectively; only values higher than 80% are reported, and black dots indicate maximally supported branches. Scale bar indicates substitutions per site.Published as part of Fassio, Giulia, Russini, Valeria, Buge, Barbara, Schiaparelli, Stefano, Modica, Maria Vittoria, Bouchet, Philippe & Oliverio, Marco, 2020, High cryptic diversity in the kleptoparasitic genus Hyalorisia Dall, 1889 (Littorinimorpha: Capulidae) with the description of nine new species from the Indo-West Pacific, pp. 401-421 in Journal of Molluscan Studies (Rijksuniversiteit te Gent. Fakulteit van de Landbouwkundige en Toegepaste Biologische Wetenschappen) 86 (4) on page 405, DOI: 10.1093/mollus/eyaa028, http://zenodo.org/record/446490
Do larval types affect genetic connectivity at sea? Testing hypothesis in two sibling marine gastropods with contrasting larval development
No full textIn marine environments, connectivity among populations of benthic invertebrates is provided primarily by dispersion of larvae, with the duration of pelagic larval phase (PLD) supposed to represent one of the major factor affecting connectivity. In marine gastropods, PLD is linked to specific larval development types, which may be entirely intracapsular (thus lacking a pelagic dispersal), or include a short pelagic lecithotrophic or a long planktotrophic phase.
In the present study, we investigated two sibling species of the cosmopolitan neogastropod genus Columbella (commonly known as dove shells): Columbella adansoni Menke, 1853, from the Macaronesian Atlantic archipelagos, with planktotrophic development, and Columbella rustica Linnaeus, 1758, from the Mediterranean Sea, with intracapsular development.
We expected to find differences between these two sister species, in terms of phylogeographic structure, levels of genetic diversification and spatial distribution of genetic diversity, if PLD was actually a relevant factor affecting connectivity.
By analysing the sequence variation at the cytochrome c oxidase subunit I (COI) in 167 specimens of the two species, collected over a comparable geographic range, we found that Columbella adansoni, the species with planktotrophic development, and thus longer PLD, showed no phylogeographic structure, lower levels of genetic diversity, interpopulational variance lower than the intrapopulational one and no spatial structure in the distribution of the genetic diversity; Columbella rustica, the species with intracapsular development, thus with evidently lower dispersal abilities, showed a clear phylogeographic structure, higher levels of genetic diversity, high interpopulational and low intrapopulational variance, and a clear signature of global spatial structure in the distribution of the genetic diversity.
Thus, in this study, two sibling species differing almost only in their larval ecology (and PLD), when compared for their genetic variation showed patterns supporting the hypothesis that PLD is a major factor affecting genetic connectivity.
Therefore, it seems reasonable to expect that the ecological attributes of the marine communities - also in terms of the variation in larval ecology of the species involved – are taken into the due consideration in conservation actions, like the design of marine protected areas networks
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