Abstract:The Gastropoda contains 80% of existing mollusks and is the most diverse animal class second only to the Insecta. However, the deep phylogeny of gastropods has been controversial for a long time. Especially the position of Patellogastropoda is a major uncertainty. Morphology and some mitochondria studies concluded that Patellogastropoda is likely to be sister to all other gastropods (Orthogastropoda hypothesis), while transcriptomic and other mitogenomic studies indicated that Patellogastropoda and Vetigastrop… Show more
“…S6 ). The results thus favor the hypothesis of a clade Orthogastropoda (the united clade of Heterobranchia, Caenogastropoda, Vetigastropoda, and Neritimorpha), which is congruent with morphology-based and recently reported mitogenomic phylogenies 32 , 34 – 36 ; but see Chen and Schrödl 37 . Figure 2 Phylogeny within gastropod lineages and gene family evolution.…”
Stylommatophoran pulmonate land slugs and snails successfully completed the water-to-land transition from an aquatic ancestor and flourished on land. Of the 30,000 estimated species, very few genomes have so far been published. Here, we assembled and characterized a chromosome-level genome of the “Spanish” slug, Arion vulgaris Moquin-Tandon, 1855, a notorious pest land slug in Europe. Using this reference genome, we conclude that a whole-genome duplication event occurred approximately 93–109 Mya at the base of Stylommatophora and might have promoted land invasion and adaptive radiation. Comparative genomic analyses reveal that genes related to the development of kidney, blood vessels, muscle, and nervous systems had expanded in the last common ancestor of land pulmonates, likely an evolutionary response to the terrestrial challenges of gravity and water loss. Analyses of A. vulgaris gene families and positively selected genes show the slug has evolved a stronger ability to counteract the greater threats of external damage, radiation, and water loss lacking a protective shell. Furthermore, a recent burst of long interspersed elements in the genome of A. vulgaris might affect gene regulation and contribute to rapid phenotype changes in A. vulgaris, which might be conducive to its rapid adaptation and invasiveness.
“…S6 ). The results thus favor the hypothesis of a clade Orthogastropoda (the united clade of Heterobranchia, Caenogastropoda, Vetigastropoda, and Neritimorpha), which is congruent with morphology-based and recently reported mitogenomic phylogenies 32 , 34 – 36 ; but see Chen and Schrödl 37 . Figure 2 Phylogeny within gastropod lineages and gene family evolution.…”
Stylommatophoran pulmonate land slugs and snails successfully completed the water-to-land transition from an aquatic ancestor and flourished on land. Of the 30,000 estimated species, very few genomes have so far been published. Here, we assembled and characterized a chromosome-level genome of the “Spanish” slug, Arion vulgaris Moquin-Tandon, 1855, a notorious pest land slug in Europe. Using this reference genome, we conclude that a whole-genome duplication event occurred approximately 93–109 Mya at the base of Stylommatophora and might have promoted land invasion and adaptive radiation. Comparative genomic analyses reveal that genes related to the development of kidney, blood vessels, muscle, and nervous systems had expanded in the last common ancestor of land pulmonates, likely an evolutionary response to the terrestrial challenges of gravity and water loss. Analyses of A. vulgaris gene families and positively selected genes show the slug has evolved a stronger ability to counteract the greater threats of external damage, radiation, and water loss lacking a protective shell. Furthermore, a recent burst of long interspersed elements in the genome of A. vulgaris might affect gene regulation and contribute to rapid phenotype changes in A. vulgaris, which might be conducive to its rapid adaptation and invasiveness.
“…The number of Mollusca species (Hung., Puhatestűek), including the three main groups of Gastropoda (snails), Bivalvia (clams or mussels), and Cephalopoda (polyps) (Henderson and Henderson, 1963) (Hung., csigák, kagylók, and polipok) globally is about 70.000 -118.000 (Bitzilekis et al, 2023) with the difficulties of double/triple description names (Rosenberg, 2014). The 80% of existing Mollusca species belongs to Gastropoda (Chen and Schrödl, 2022). Fossils and petrified Mollusca species (Fig.…”
Land snail Xerolenta (Syn.,Helicella)obvia[MENKE,1828] (Eng., heath snail; Hung., lapos kórócsiga) (1.5-2.0 cm) was analyzed here by in silicodata mining at the DNA sequence site of 18S ribosomal RNAgene (1801 bp; GenBank# GU331943.1)to findthemostrelated snail species. Sequence and dendrogram analysisrevealed thatthe pest land snail Acusta despecta sieboldiana[SOWERBY,1839;PFEIFFER,1850]showsthe closest genetic distanceto X. obvia.The ecological and medicinal impactsof sea and land snail mollusks are indicated.
Mollusca, the second‐most diverse animal phylum, is estimated to have over 100,000 living species with great genetic and phenotypic diversity, a rich fossil record, and a considerable evolutionary significance. Early work on molluscan systematics was grounded in morphological and anatomical studies. With the transition from oligo gene Sanger sequencing to cutting‐edge genomic sequencing technologies, molecular data has been increasingly utilised, providing abundant information for reconstructing the molluscan phylogenetic tree. However, relationships among and within most major lineages of Mollusca have long been contentious, often due to limited genetic markers, insufficient taxon sampling and phylogenetic conflict. Fortunately, remarkable progress in molluscan systematics has been made in recent years, which has shed light on how major molluscan groups have evolved. In this review of molluscan systematics, we first synthesise the current understanding of the molluscan Tree of Life at higher taxonomic levels. We then discuss how micromolluscs, which have adult individuals with a body size smaller than 5 mm, offer unique insights into Mollusca's vast diversity and deep phylogeny. Despite recent advancements, our knowledge of molluscan systematics and phylogeny still needs refinement. Further advancements in molluscan systematics will arise from integrating comprehensive data sets, including genome‐scale data, exceptional fossils, and digital morphological data (including internal structures). Enhanced access to these data sets, combined with increased collaboration among morphologists, palaeontologists, evolutionary developmental biologists, and molecular phylogeneticists, will significantly advance this field.
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