Marseniopsis Bergh, 1886 is a genus of marine gastropods (Velutinidae) which includes nine described species, eight of which endemic to Antarctica. This genus is known to feed on tunicates and is characterized by a peculiar planktotrophic larva, the “limacosphaera”, with a potentially long pelagic life, which is a really uncommon developmental strategy for Antarctic gastropods. In the framework of recent scientific expeditions held in the Ross Sea, at the tip of the Antarctic Peninsula and in Weddell sector, a special effort was done in documenting with digital pictures the colour pattern of the different species routinely encountered during sampling activities. Thanks to this live-collected new material, several different colour patterns, within and amongst presumed conspecific samples, were documented, suggesting the existence of at least a partially underestimated diversity. Based on this unprecedented large sampling, our aim was to define the actual diversity of the Antarctic Marseniopsis, including the identification of cryptic species through an integrative taxonomy approach. Our dataset included 78 COI barcode sequences, out of which 21 originate from 18 sampling sites in the Ross Sea and other 57 from 13 sampling sites in the Weddell Sea- Antarctic Peninsula. Through genetic distances, we identified 13 MOTUs, 9 of which exclusively from the Weddell Sea-Antarctic Peninsula and four occurring also in the Ross sea. Automatic Barcode Gap Discovery (ABGD) analysis confirmed the same samples partition and identified a barcoding gap around 2% of genetic distance. The isolation-by-distance analysis did not show any significant correlation between genetic and geographic distances among populations of each clade. These results suggest the presence of a hidden biodiversity of Antarctic Marseniopsis that, if confirmed by further analysis, will almost double the number of species of this genus. In addition, the absence of isolation-by-distance and the presence of some MOTUs in both seas, are congruent with the long pelagic life of the Marseniopsis larva.
Hidden biodiversity of Antarctic Marseniopsis (Velutinidae) / Fassio, Giulia; Oliverio, Marco; Mc, Alvaro; Modica, MARIA VITTORIA; S., Schiaparelli. - STAMPA. - (2014). (Intervento presentato al convegno 7th Congress of the European Malacological Societies tenutosi a Cambridge, UK nel 7-11 Settembre 2014).
Hidden biodiversity of Antarctic Marseniopsis (Velutinidae)
FASSIO, GIULIA;OLIVERIO, Marco;MODICA, MARIA VITTORIA;
2014
Abstract
Marseniopsis Bergh, 1886 is a genus of marine gastropods (Velutinidae) which includes nine described species, eight of which endemic to Antarctica. This genus is known to feed on tunicates and is characterized by a peculiar planktotrophic larva, the “limacosphaera”, with a potentially long pelagic life, which is a really uncommon developmental strategy for Antarctic gastropods. In the framework of recent scientific expeditions held in the Ross Sea, at the tip of the Antarctic Peninsula and in Weddell sector, a special effort was done in documenting with digital pictures the colour pattern of the different species routinely encountered during sampling activities. Thanks to this live-collected new material, several different colour patterns, within and amongst presumed conspecific samples, were documented, suggesting the existence of at least a partially underestimated diversity. Based on this unprecedented large sampling, our aim was to define the actual diversity of the Antarctic Marseniopsis, including the identification of cryptic species through an integrative taxonomy approach. Our dataset included 78 COI barcode sequences, out of which 21 originate from 18 sampling sites in the Ross Sea and other 57 from 13 sampling sites in the Weddell Sea- Antarctic Peninsula. Through genetic distances, we identified 13 MOTUs, 9 of which exclusively from the Weddell Sea-Antarctic Peninsula and four occurring also in the Ross sea. Automatic Barcode Gap Discovery (ABGD) analysis confirmed the same samples partition and identified a barcoding gap around 2% of genetic distance. The isolation-by-distance analysis did not show any significant correlation between genetic and geographic distances among populations of each clade. These results suggest the presence of a hidden biodiversity of Antarctic Marseniopsis that, if confirmed by further analysis, will almost double the number of species of this genus. In addition, the absence of isolation-by-distance and the presence of some MOTUs in both seas, are congruent with the long pelagic life of the Marseniopsis larva.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
