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12 pages, 2727 KiB

Open AccessEditor’s ChoiceArticle

Being Safe, but Not Too Safe: A Nudibranch Feeding on a Bryozoan-Associated Hydrozoan

by Davide Maggioni, Giulia Furfaro, Michele Solca, Davide Seveso, Paolo Galli and Simone Montano

Diversity 2023, 15(4), 484; https://doi.org/10.3390/d15040484 - 24 Mar 2023

Viewed by 2224

Abstract

Nudibranchs have a mostly carnivorous diet, and they prey on a wide variety of other animal taxa. Many species, mainly belonging to the Cladobranchia suborder, feed on cnidarians, including member of the class Hydrozoa. Several hydrozoan species display a symbiotic lifestyle, being associated [...] Read more.

Nudibranchs have a mostly carnivorous diet, and they prey on a wide variety of other animal taxa. Many species, mainly belonging to the Cladobranchia suborder, feed on cnidarians, including member of the class Hydrozoa. Several hydrozoan species display a symbiotic lifestyle, being associated with other benthic invertebrates, including for instance bryozoans, corals, octocorals, and sponges. In our knowledge, no record of nudibranch predation on symbiotic hydrozoans has been reported so far, possibly thanks to the protective action by the host towards its symbiotic hydrozoan. Here, we show the unexpected case of a nudibranch belonging to the recently described species Sakuraeolis marhe (Fernández-Simón and Moles, 2023) feeding on Zanclea sp. 2, a hydrozoan associated with the cheilostome bryozoan Celleporaria sp. This trophic association is confirmed by the presence and storage of the nematocysts into the nudibranch cnidosacs. Moreover, the nudibranch appears to selectively store mostly a single type of nematocyst, that is large size stenotele. The observation here reported represents the first well-documented record of a nudibranch feeding on a symbiotic hydrozoan and the first confirmed case of predation on Zanclea polyps. Moreover, we provide additional genetic information and the first description of the internal anatomy of S. marhe. Full article

(This article belongs to the Special Issue Systematics and Evolution of Gastropods)

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27 pages, 4531 KiB

Open AccessArticle

Is a Modified Actin the Key to Toxin Resistance in the Nudibranch Chromodoris? A Biochemical and Molecular Approach

by Cora Hertzer, Nani Ingrid Jacquline Undap, Adelfia Papu, Dhaka Ram Bhandari, Stefan Aatz, Stefan Kehraus, Fontje Kaligis, Robert Bara, Till F. Schäberle, Heike Wägele and Gabriele M. König

Diversity 2023, 15(2), 304; https://doi.org/10.3390/d15020304 - 18 Feb 2023

Viewed by 2293

Abstract

Five Chromodoris species from North Sulawesi, Indonesia, were investigated for their sequestration of marine natural products. The cytotoxic 2-thiazolidinone macrolide latrunculin A (LatA) was the major metabolite in all examined Chromodoris species, as well as in one of the associated sponges Cacospongia mycofijiensis [...] Read more.

Five Chromodoris species from North Sulawesi, Indonesia, were investigated for their sequestration of marine natural products. The cytotoxic 2-thiazolidinone macrolide latrunculin A (LatA) was the major metabolite in all examined Chromodoris species, as well as in one of the associated sponges Cacospongia mycofijiensis (Kakou, Crews & Bakus, 1987), supporting a dietary origin of LatA. Furthermore, LatA was secreted with the mucus trail, suggesting a possible use in short-range chemical communication. MALDI MS-Imaging revealed an accumulation of LatA throughout the mantle tissue, mucus glands, and especially in vacuoles of the mantle dermal formations (MDFs). Cytotoxicity of the isolated LatA was tested in HEK-293 cells, confirming that LatA targets the actin cytoskeleton. In vivo toxicity experiments with the sacoglossan Elysia viridis (Montagu, 1804) showed 100% mortality, but 100% survival of Chromodoris specimens, demonstrating resistance to LatA. A novel actin isoform was detected in all investigated Chromodoris species with two amino acid substitutions at the ‘nucleotide binding’ cleft, the binding site of LatA. These are suggested to cause insensitivity against LatA, thus enabling the storage of the toxin within the body for the slugs’ own defense. Full article

(This article belongs to the Special Issue Systematics and Evolution of Gastropods)

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23 pages, 6858 KiB

Open AccessEditor’s ChoiceArticle

Mediterranean Matters: Revision of the Family Onchidorididae (Mollusca, Nudibranchia) with the Description of a New Genus and a New Species

by Giulia Furfaro, Egidio Trainito, Marco Fantin, Marcella D’Elia, Enric Madrenas and Paolo Mariottini

Diversity 2023, 15(1), 38; https://doi.org/10.3390/d15010038 - 29 Dec 2022

Cited by 5 | Viewed by 2209

Abstract

The Mediterranean Sea hosts a great Nudibranchia diversity and has proved to be particularly intriguing in the case of the family Onchidorididae, a group of dorid nudibranchs that lately increased its diversity with the addition of one recently described Mediterranean species. The Onchidorididae [...] Read more.

The Mediterranean Sea hosts a great Nudibranchia diversity and has proved to be particularly intriguing in the case of the family Onchidorididae, a group of dorid nudibranchs that lately increased its diversity with the addition of one recently described Mediterranean species. The Onchidorididae family has a troubled systematic history to date, characterized by uncertainties and genera that are considered valid or not, according to the different authors. This confused taxonomy reflects the lack of a broad and comprehensive view on the phylogenetic relationships occurring between Onchidorididae members, an incorrect interpretation of the diagnostic morphological characters, and a poor knowledge of important biological aspects characterizing the different genera included in the family. To shed some light on the systematics of Onchidorididae, an integrative taxonomic revision was carried out involving morphological, ecological, and molecular analyses on an updated dataset. Mediterranean specimens and species were added to the dataset of the already known Onchidorididae and a new species from the Adriatic Sea (Central Mediterranean Sea) is described here. Furthermore, historical controversies are clarified due to the discovery of new important synapomorphies useful to define genera belonging to the Onchidorididae family and to describe a new genus. Finally, the taxonomic status of all the known Onchidorididae species is investigated and discussed, filling the gap of knowledge on neglected species. Full article

(This article belongs to the Special Issue Systematics and Evolution of Gastropods)

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16 pages, 15057 KiB

Open AccessArticle

How Many Abalone Species Live in the Mediterranean Sea?

by Giacomo Chiappa, Giulia Fassio, Andrea Corso, Fabio Crocetta, Maria Vittoria Modica and Marco Oliverio

Diversity 2022, 14(12), 1107; https://doi.org/10.3390/d14121107 - 13 Dec 2022

Cited by 3 | Viewed by 3777

Abstract

Morphological traits in Haliotidae may be highly variable and not consistently diagnostic for species identification, highlighting the need for an integrative approach to the taxonomy of the family, including genetic data. Four species of the genus Haliotis are currently reported for the Mediterranean [...] Read more.

Morphological traits in Haliotidae may be highly variable and not consistently diagnostic for species identification, highlighting the need for an integrative approach to the taxonomy of the family, including genetic data. Four species of the genus Haliotis are currently reported for the Mediterranean Sea and the neighboring Atlantic Ocean: Haliotis tuberculata, the common European abalone with the widest Atlanto-Mediterranean range; Haliotis mykonosensis, from the Aegean, the Tyrrhenian, and the Adriatic; Haliotis stomatiaeformis, from Malta, Lampedusa, and southeastern Sicily; and the Lessepsian Haliotis pustulata, only known on the basis of few samples from the Levant. However, their taxonomic status still relies only on shell morphology. Here, sequences of two fragments of the mitochondrial molecular marker COI were obtained from 84 abalone specimens collected in the Mediterranean Sea and the neighboring Atlantic and analyzed in order to provide for the first time a genetic framework for species delimitation. This study’s results prove that H. mykonosensis is genetically identical to H. tuberculata, whereas H. stomatiaeformis is a distinct species, endemic to a restricted area of the southern Mediterranean Sea. Finally, Haliotis tuberculata coccinea from Macaronesia may deserve its status as a subspecies of H. tuberculata, with genetic signature of a limited gene flow found in specimens of the nominal subspecies (H. t. tuberculata) in both the Atlantic and the Mediterranean Sea. Full article

(This article belongs to the Special Issue Systematics and Evolution of Gastropods)

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24 pages, 5348 KiB

Open AccessArticle

Mollusc Crystallins: Physical and Chemical Properties and Phylogenetic Analysis

by Irina N. Dominova and Valery V. Zhukov

Diversity 2022, 14(10), 827; https://doi.org/10.3390/d14100827 - 01 Oct 2022

Cited by 2 | Viewed by 1546

Abstract

The purpose of the present study was to perform bioinformatic analysis of crystallin diversity in aquatic molluscs based on the sequences in the NCBI Protein database. The objectives were as follows: (1) analysis of some physical and chemical properties of mollusc crystallins, (2) [...] Read more.

The purpose of the present study was to perform bioinformatic analysis of crystallin diversity in aquatic molluscs based on the sequences in the NCBI Protein database. The objectives were as follows: (1) analysis of some physical and chemical properties of mollusc crystallins, (2) comparison of mollusc crystallins with zebrafish and cubomedusa Tripedalia cystophora crystallins, and (3) determination of the most probable candidates for the role of gastropod eye crystallins. The calculated average GRAVY values revealed that the majority of the seven crystallin groups, except for μ- and ζ-crystallins, were hydrophilic proteins. The predominant predicted secondary structures of the crystallins in most cases were α-helices and coils. The highest values of refractive index increment (dn/dc) were typical for crystallins of aquatic organisms with known lens protein composition (zebrafish, cubomedusa, and octopuses) and for S-crystallin of Pomacea canaliculata. The evolutionary relationships between the studied crystallins, obtained from multiple sequence alignments using Clustal Omega and MUSCLE, and the normalized conservation index, calculated by Mirny, showed that the most conservative proteins were Ω-crystallins but the most diverse were S-crystallins. The phylogenetic analysis of crystallin was generally consistent with modern mollusc taxonomy. Thus, α- and S-, and, possibly, J1A-crystallins, can be assumed to be the most likely candidates for the role of gastropod lens crystallins. Full article

(This article belongs to the Special Issue Systematics and Evolution of Gastropods)

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16 pages, 2424 KiB

Open AccessArticle

Alien Travel Companies: The Case of Two Sea Slugs and One Bryozoan in the Mediterranean Sea

by Erika Mioni and Giulia Furfaro

Diversity 2022, 14(8), 687; https://doi.org/10.3390/d14080687 - 21 Aug 2022

Cited by 3 | Viewed by 1906

Abstract

Mediterranean marine fauna is constantly changing due to the entry of non-indigenous (NI) species and the loss of endemic biodiversity. In this framework, it is very important to monitor this constant change and investigate possible new pathways of dispersion. Marinas and ports are [...] Read more.

Mediterranean marine fauna is constantly changing due to the entry of non-indigenous (NI) species and the loss of endemic biodiversity. In this framework, it is very important to monitor this constant change and investigate possible new pathways of dispersion. Marinas and ports are considered key stations to detect and study some important ecological aspects, such as NI and invasive species, the effects of climate change, and pollution. Here, we reported the case of a group of NI species that presumably reached the Mediterranean Sea together, each of them being ecologically associated with one another. The bryozoan Amathia verticillate and the sea slugs Favorinus ghanensis and Polycerella emertoni were found in the shallow waters of Fezzano’s marina in the gulf of La Spezia (Ligurian Sea, Mediterranean Sea). Molecular analyses were carried out to exclude cryptic diversity and to investigate the phylogenetic relationships occurring between closely related taxa. The spreading of these two NI sea slugs into the Mediterranean Sea was confirmed and the first record of P. emertoni from the Ligurian Sea reported. These findings shed some light on the poorly known ecology of these species that could be useful for future monitoring and conservation strategies. Full article

(This article belongs to the Special Issue Systematics and Evolution of Gastropods)

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17 pages, 2208 KiB

Open AccessArticle

The Sea Slug Doriopsilla areolata Bergh, 1880 (Mollusca, Gastropoda) in the Mediterranean Sea: Another Case of Cryptic Diversity

by Giulia Furfaro, Christopher Schreier, Egidio Trainito, Miquel Pontes, Enric Madrenas, Pascal Girard and Paolo Mariottini

Diversity 2022, 14(4), 297; https://doi.org/10.3390/d14040297 - 15 Apr 2022

Cited by 6 | Viewed by 3466

Abstract

The Mediterranean Sea diversity is still far from being fully disclosed. Marine Heterobranchia are one of the most paradigmatic species-rich groups, with many recent systematic studies revealing the high density of new, cryptic, and endemic species occurring in the Mediterranean basin. In this [...] Read more.

The Mediterranean Sea diversity is still far from being fully disclosed. Marine Heterobranchia are one of the most paradigmatic species-rich groups, with many recent systematic studies revealing the high density of new, cryptic, and endemic species occurring in the Mediterranean basin. In this study, sea slug Doriopsilla areolata, which was considered until today one of the most widespread nudibranchs worldwide, was investigated using a molecular approach to compare Mediterranean and Atlantic populations for the first time. The molecular analyses involved three different molecular markers, the two mitochondrial COI and 16S, and the nuclear H3 gene. The results revealed a complex of species within D. areolata that indeed consists of three potentially species, two of which are endemic to the Mediterranean Sea: Doriopsilla areolata, which is distributed in the Adriatic Sea (the type locality of the former species), D. rarispinosa, which occurs in the Western Mediterranean basin and along the Tunisian coast, and one additional Atlantic species here provisionally defined as Doriopsilla sp. 1. This study helps to unveil another case of cryptic diversity within Mediterranean Heterobranchia and to increase the knowledge on Doriopsilla genus diversity. Full article

(This article belongs to the Special Issue Systematics and Evolution of Gastropods)

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30 pages, 9976 KiB

Open AccessArticle

Stripes Matter: Integrative Systematics of Coryphellina rubrolineata Species Complex (Gastropoda: Nudibranchia) from Vietnam

by Irina Ekimova, Yury Deart, Tatiana Antokhina, Anna Mikhlina and Dimitry Schepetov

Diversity 2022, 14(4), 294; https://doi.org/10.3390/d14040294 - 13 Apr 2022

Cited by 7 | Viewed by 3442

Abstract

Coryphellina rubrolineata (Gastropoda: Nudibranchia: Flabellinidae) was believed to be a widespread tropical species demonstrating high diversity in external and internal morphological traits. In this paper, we perform an integrative analysis of the C. rubrolineata species complex based on samples collected in Vietnam waters, [...] Read more.

Coryphellina rubrolineata (Gastropoda: Nudibranchia: Flabellinidae) was believed to be a widespread tropical species demonstrating high diversity in external and internal morphological traits. In this paper, we perform an integrative analysis of the C. rubrolineata species complex based on samples collected in Vietnam waters, combined with available data from other localities of the Indo-West Pacific. The methods of the study include morphological analysis of external and internal traits using light and scanning electron microscopy and the molecular analysis of four markers (COI, 16S, H3, and 28S). The phylogenetic hypothesis was performed using Bayesian and maximum likelihood approaches, and the species delimitation analyses included ASAP, GMYC, and bPTP. Our results support the validity of the genus Coryphellina as a distinct taxon and confirm that Coryphellina rubrolineata is restricted to the type locality and adjacent waters, while in the Indo-West Pacific, it represents a complex of pseudocryptic species. Based on our integrative analysis, we describe four new species: Coryphellina pseudolotos sp. nov., Coryphellina pannae sp. nov., Coryphellina flamma sp. nov., and Coryphellina aurora sp. nov. For the first time, Coryphellina lotos is reported in Vietnam waters. All five species differ in combination of coloration and other external traits and show minor differences in internal morphology. Full article

(This article belongs to the Special Issue Systematics and Evolution of Gastropods)

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3 pages, 3959 KiB

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Aposymbiotic Specimen of the Photosynthetic Sea Slug Elysia crispata

by Paulo Cartaxana, Diana Lopes, Begoña Martinez, Patrícia Martins and Sónia Cruz

Diversity 2022, 14(5), 313; https://doi.org/10.3390/d14050313 - 20 Apr 2022

Cited by 1 | Viewed by 2523

Abstract

Elysia crispata is a sacoglossan sea slug that retains intracellular, functional chloroplasts stolen from their macroalgal food sources. Elysia crispata juveniles start feeding on the algae following metamorphosis, engulfing chloroplasts and turning green. In laboratory-reared animals, we report one juvenile “albino” specimen unable [...] Read more.

Elysia crispata is a sacoglossan sea slug that retains intracellular, functional chloroplasts stolen from their macroalgal food sources. Elysia crispata juveniles start feeding on the algae following metamorphosis, engulfing chloroplasts and turning green. In laboratory-reared animals, we report one juvenile “albino” specimen unable to retain chloroplasts. Within 6 weeks post-metamorphosis, the aposymbiotic sea slug was significantly smaller than its chloroplast-bearing siblings. This evidence highlights that chloroplast acquisition is required for the normal development of E. crispata. Full article

(This article belongs to the Special Issue Systematics and Evolution of Gastropods)

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