Research

14 pages, 6369 KiB

Open AccessArticle

Who Lives in the Hot Heart of the Cold Sea? A New Species of Provanna (Caenogastropoda: Provannidae) from the Hydrothermal Zone of Piip Volcano, Northwestern Pacific

by Ivan O. Nekhaev

Diversity 2023, 15(4), 581; https://doi.org/10.3390/d15040581 - 21 Apr 2023

Cited by 3 | Viewed by 1554

Abstract

The benthic macrofauna of Arctic and subarctic seas is mainly represented by widespread species and is generally devoid of endemics. The exceptions are reduced habitats, such as cold seeps, hydrothermal areas, and wood falls, which include endemics of at least the species level. [...] Read more.

The benthic macrofauna of Arctic and subarctic seas is mainly represented by widespread species and is generally devoid of endemics. The exceptions are reduced habitats, such as cold seeps, hydrothermal areas, and wood falls, which include endemics of at least the species level. A detailed study and analysis of such endemics allows us to understand the mechanisms of colonization and to assess the age of the fauna of high-latitude marine regions. Here, the new species Provanna annae sp. nov. is described from the geothermal zone of the Piip volcano in the Bering Sea (subarctic Pacific) based on the morphological and molecular phylogenetic data. The new species appears to be the northernmost and one of the most shallow-water species among the known representatives of the family and is suggested to be endemic to the region. The new species is related to a group of Provanna species from reducing habitats off Japan. Composition of the gut content indicates that the new species bottom sediments. Bacteria are found on the gills of the mollusc and are probably symbionts that also provide nutrition. This type of mixotrophic feeding is rare in gastropods and may be a unique feature among Caenogastropoda. Full article

(This article belongs to the Special Issue Systematics, Phylogeography, Evolution and Conservation of Molluscs)

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32 pages, 5551 KiB

Open AccessArticle

How an Ecological Race Is Forming: Morphological and Genetic Disparity among Thermal and Non-Thermal Populations of Aquatic Lymnaeid Snails (Gastropoda: Lymnaeidae)

by Maxim V. Vinarski, Olga V. Aksenova, Yulia V. Bespalaya, Mikhail Yu. Gofarov, Alexander V. Kondakov, Irina S. Khrebtova, Alexander A. Makhrov and Ivan N. Bolotov

Diversity 2023, 15(4), 548; https://doi.org/10.3390/d15040548 - 12 Apr 2023

Viewed by 2519

Abstract

Hot (geothermal) pools and streams, a specific type of aquatic biotopes having almost worldwide distribution, maintain rich faunas of animals belonging to various taxa. Snails (Gastropoda) represent one of such groups, which form populations in geothermal waterbodies of all continents. Some freshwater snail [...] Read more.

Hot (geothermal) pools and streams, a specific type of aquatic biotopes having almost worldwide distribution, maintain rich faunas of animals belonging to various taxa. Snails (Gastropoda) represent one of such groups, which form populations in geothermal waterbodies of all continents. Some freshwater snail species produce morphologically distinct hot-water populations, whose rank is often debated (full species or thermal ‘ecotype’, or ‘race’). In this study, we used six species of pond snails (family Lymnaeidae) to investigate the morphological and genetic consequences of infiltration of freshwater snails into geothermal habitats. In particular, we aimed at studying the changes in shell shape and proportions as well as the formation of unique hot-water haplotypes and the occurrence of the latter beyond geothermal waterbodies. All six species studied demonstrate diminutive body size in hot sites accompanied, in four species, by apparent alterations in shell proportions. A phenomenon of phenotypic ‘juvenilization’, when adult and able to reproduce individuals demonstrate shell proportions characteristic for full-grown individuals living under ‘normal’ conditions, is described. Unique ‘thermal’ haplotypes, not found beyond the geothermal sites, were normally restricted to a single locality, and no signs of frequent ‘travels’ of snails from one thermal habitat to another are seen. In the vast majority of cases, these exclusive haplotypes are separated from their ancestors by only a few (1–3) mutational steps, which may indicate their relatively recent origin. We are inclined to relate both size reduction and ‘juvenilization’ to the life-cycle re-adjustment following the penetration of lymnaeids to thermal habitats. The ecological (‘thermal’) intraspecific races of different species, forming in geothermal habitats, exhibit, to a great extent, evolutionary predictability (=convergent evolution; =parallelisms). The dilemma ‘ecological race vs. young species’ in application to the taxonomy of these hot-water populations is briefly discussed. Full article

(This article belongs to the Special Issue Systematics, Phylogeography, Evolution and Conservation of Molluscs)

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25 pages, 7263 KiB

Open AccessArticle

The North Asian Genus Kolhymamnicola Starobogatov and Budnikova 1976 (Gastropoda: Amnicolidae), Its Extended Diagnosis, Distribution, and Taxonomic Relationships

by Tatiana Sitnikova, Tatiana Peretolchina, Larisa Prozorova, Dmitry Sherbakov, Eugeny Babushkin and Maxim Vinarski

Diversity 2023, 15(4), 483; https://doi.org/10.3390/d15040483 - 24 Mar 2023

Viewed by 1304

Abstract

The taxonomic position and phylogenetic affinities of the endemic North Asian genus Kolhymamnicola Starobogatov and Budnikova, 1976 (Gastropoda: Amnicolidae) remain unknown. To resolve this, we studied key morpho-anatomical characteristics of Kolhymamnicola snails and performed a molecular phylogenetic analysis based on sequences of COI [...] Read more.

The taxonomic position and phylogenetic affinities of the endemic North Asian genus Kolhymamnicola Starobogatov and Budnikova, 1976 (Gastropoda: Amnicolidae) remain unknown. To resolve this, we studied key morpho-anatomical characteristics of Kolhymamnicola snails and performed a molecular phylogenetic analysis based on sequences of COI mtDNA, 16S rRNA, and 18S rRNA genes. In terms of protoconch microsculpture, operculum, radular teeth, and gill complex morphology, Kolhymamnicola snails do not differ significantly from the North American genera Amnicola Gould and Haldeman, 1840 and Taylorconcha Hershler et al., 1994, and the European genus Marstoniopsis van Regteren Altena 1936. The bifid penis found in Kolhymamnicola is similar to that in the genus Marstoniopsis. The female reproductive anatomy has some features shared by Kolhymamnicola and Taylorconcha (absence of bursa copulatrix, single seminal receptacle in rs_2′ position, and ventral channel). The molecular analysis has revealed Taylorconcha as the closest relative to Kolhymamnicola; the COI-based genetic distance between them amounted to 0.113. We discuss the possible time of divergence of these two genera, as well as of European Marstoniopsis and the Baikal Lake endemic family Baicaliidae. The last common ancestor of these groups was widely distributed in Miocene–Pliocene in the Holarctic waterbodies. Recent Kolhymamnicola snails are distributed in Northern Asia, including lakes of the Baikal rift zone. We rank the Baicaliidae as a family rather than a subfamily of Amnicolidae based on their distinct, unique morpho-anatomical characteristics and highly supported separate position on the molecular tree. The tribe Erhaiini Davis and Kuo, 1985 is elevated to the rank of the family, with 3–4 recent genera included. The family Palaeobaicaliidae Sitnikova et Vinarski fam. nov. is established to embrace the Cretaceous North Asian gastropods conchologically similar to the recent Baicaliidae and Pyrgulidae. Full article

(This article belongs to the Special Issue Systematics, Phylogeography, Evolution and Conservation of Molluscs)

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19 pages, 4780 KiB

Open AccessArticle

Reproductive Biology of the Golden Cuttlefish Sepia esculenta (Cephalopoda, Sepiida)

by Elizaveta V. Vlasova, Rushan M. Sabirov and Alexey V. Golikov

Diversity 2023, 15(3), 455; https://doi.org/10.3390/d15030455 - 18 Mar 2023

Cited by 1 | Viewed by 2917

Abstract

The golden cuttlefish Sepia esculenta is the one of most abundant cuttlefish species around south-east Asia and has a high commercial value. Despite its wide distribution and high commercial value, its reproductive biology is still poorly understood. This study was based on 25 [...] Read more.

The golden cuttlefish Sepia esculenta is the one of most abundant cuttlefish species around south-east Asia and has a high commercial value. Despite its wide distribution and high commercial value, its reproductive biology is still poorly understood. This study was based on 25 males and 6 females. The potential fecundity (PF) of females was 1701–3719 oocytes, which was an increase, as compared to the previously known values. The oocyte resorption reached up to 13.2% of fecundity. The ovulation pattern was group-synchronous, with a predominance of previtellogenic oocytes. The pre-meiotic and primary growth oocyte phases were absent in mature females. The number of spermatophores carried by an individual male was 146–1698 (length 9–20 mm). The spermatophores were characterised by a cement body consisting of conical oral and cylindrical aboral parts. The ontogenetic changes in the spermatophores and their parts were recorded for the first time in the order of Sepiida. Their sperm content and their adhesive abilities also increased during ontogenesis. The data obtained in the present study significantly increased and corrected the existing knowledge of S. esculenta biology. Moreover, these data help to explain the general patterns of reproductive biology in cuttlefish, as well as in Cephalopoda as a whole. Full article

(This article belongs to the Special Issue Systematics, Phylogeography, Evolution and Conservation of Molluscs)

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18 pages, 2444 KiB

Open AccessArticle

Bizarre Morphology Obscures Real Affiliation: An Integrative Study of Enigmatic Cephalaspid Philine denticulata from Arctic Waters Reveals Its Unique Phylogenetic Position

by Elena Chaban, Irina Ekimova, Pavel Lubin, Ekaterina Nikitenko and Dimitry Schepetov

Diversity 2023, 15(3), 395; https://doi.org/10.3390/d15030395 - 09 Mar 2023

Viewed by 1267

Abstract

The biodiversity of Cephalaspidea (Gastropoda: Heterobranchia) is poorly studied, and novel findings often lead to revisions at different taxonomic levels. The family Philinidae has a distinct set of defining characters in the shell, copulatory apparatus, and gizzard morphology, but several species, considered part [...] Read more.

The biodiversity of Cephalaspidea (Gastropoda: Heterobranchia) is poorly studied, and novel findings often lead to revisions at different taxonomic levels. The family Philinidae has a distinct set of defining characters in the shell, copulatory apparatus, and gizzard morphology, but several species, considered part of the family, deviate from it significantly. Philine denticulata (J. Adams, 1800) was considered to be a Philinidae despite the species morphology not fitting well with the family diagnosis. This species has an oval cylindrical external shell, jaws, and a gizzard lined with a chitinous layer with three thickened ridges. We studied Philine denticulata morphology on samples from the White and Barents Seas using the light and scanning electron microscopy methods in addition to computer microtomography. We also reconstructed its phylogenetic position using COI, 16S, 28S, and H3 genetic markers. Our integrative analysis revealed close relationships of this species to the family Aglajidae. Thus, we describe a new genus Philinissima gen. nov., including a single species Philinissima denticulata (J. Adams, 1800) comb. nov. which is the first aglajid registered from the Arctic waters. Our findings highlight possible problems in the Aglajidae taxonomical composition and an overall need for a dedicated integrative revision of the Cephalaspidea. Full article

(This article belongs to the Special Issue Systematics, Phylogeography, Evolution and Conservation of Molluscs)

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16 pages, 1390 KiB

Open AccessArticle

Do Deep Mitochondrial DNA Divergences within Intertidal Gastropods Reveal Phylogeographic Signals from Earlier Glacial Cycles?

by Donald James Colgan

Diversity 2023, 15(3), 346; https://doi.org/10.3390/d15030346 - 01 Mar 2023

Viewed by 1134

Abstract

Climatic cycles have frequently been hypothesised to influence the phylogeography of temperate marine organisms through such factors as hydrological changes and landbridge formation at glacial maxima. However, it is rarely considered whether observed phylogeographic patterns are predominantly influenced by the most recent cycle [...] Read more.

Climatic cycles have frequently been hypothesised to influence the phylogeography of temperate marine organisms through such factors as hydrological changes and landbridge formation at glacial maxima. However, it is rarely considered whether observed phylogeographic patterns are predominantly influenced by the most recent cycle or those that preceded it. Whether high genetic divergences within intertidal taxa provide an opportunity to investigate such questions is studied here. Three southeastern Australian gastropod taxa that exhibit such divergence were studied, namely, Ascorhis tasmanica, Phallomedusa solida and the regions’ two species of the genus Nerita. Maximum likelihood phylogenetic analyses revealed bootstrap-supported clades within Nerita atramentosa, N. melanotragus and P. solida each of which may have been influenced by climatically induced isolation in previous glacial cycles. These clades are all now very widely distributed within the ranges of their respective species. The loss of variants resulting in the divergence of the haplotypes in the clades may be stochastic but was more likely due to selection, at least for P. solida. Ascorhis tasmanica was revealed to have a comparatively large number of sporadically distributed divergent groups; however, their evolution may have been more influenced by factors other than climate cycles. Full article

(This article belongs to the Special Issue Systematics, Phylogeography, Evolution and Conservation of Molluscs)

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11 pages, 1394 KiB

Open AccessArticle

Mate Choice in Molluscs of the Genus Littorina (Gastropoda: Littorinidae) from White Sea

by Eugene V. Kozminsky, Elena A. Serbina and Alexey O. Smurov

Diversity 2023, 15(2), 297; https://doi.org/10.3390/d15020297 - 17 Feb 2023

Viewed by 1408

Abstract

We studied the reproductive behaviour associated with mate choice by size in three species of White Sea molluscs of the genus Littorina—L. saxatilis, L. obtusata and L. fabalis. Three behavioural patterns were revealed after a comparative analysis of the [...] Read more.

We studied the reproductive behaviour associated with mate choice by size in three species of White Sea molluscs of the genus Littorina—L. saxatilis, L. obtusata and L. fabalis. Three behavioural patterns were revealed after a comparative analysis of the behaviour of the male snails. The males of L. obtusata, regardless of their size, could mate with all females but preferred to mate with larger ones. The males of L. fabalis chose females of their own size or larger. The males of L. saxatilis mated with females of approximately their own size. In the first case (L. obtusata), there is a free exchange of genes between all the size groups in the population. In the second case (L. fabalis), the gene transfer from small males to females of any size is free but the gene transfer from large males to small females is limited. In the third case (L. saxatilis), the gene flow is limited between groups of individuals of dramatically different size. Thus, in the case of L. saxatilis and L. fabalis, to varying degrees restriction of random mating associated with size assortativity in choosing a mating partner was expressed, which under certain circumstances (divergence of individuals in different econiches, the presence of ecotypes differing in size, lack of stronger natural selection in the other direction) can favour sympatric speciation. The males of all the three periwinkles’ species preferred larger females but sexual selection in favour of larger females was found only in L. obtusata. In the other two species, there were no statistically significant size differences between copulating and non-copulating females. This appears to be due to the occurrence of size-assortative mating in these species, which limits the ability of males to choose larger female partners. Full article

(This article belongs to the Special Issue Systematics, Phylogeography, Evolution and Conservation of Molluscs)

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13 pages, 1974 KiB

Open AccessArticle

Phylogeography and Genetic Diversity of Duck Mussel Anodonta anatina (Bivalvia: Unionidae) in Eurasia

by Artem A. Lyubas, Alena A. Tomilova, Alexander V. Kondakov, Ekaterina S. Konopleva, Ilya V. Vikhrev, Mikhail Yu. Gofarov, Tatyana A. Eliseeva, Olga V. Aksenova, Galina V. Bovykina, Darya V. Kryuk, Tatyana L. Gorbunova, Oxana Munjiu, Oleg S. Pokrovsky and Ivan N. Bolotov

Diversity 2023, 15(2), 260; https://doi.org/10.3390/d15020260 - 12 Feb 2023

Cited by 4 | Viewed by 2077

Abstract

The duck mussel Anodonta anatina is widely distributed throughout the freshwater basins of Northern, Central, and Western Eurasia, and it has a comprehensive genetic structure. This study was devoted to the analysis of lineages, which are defined based on COI gene sequences. Our [...] Read more.

The duck mussel Anodonta anatina is widely distributed throughout the freshwater basins of Northern, Central, and Western Eurasia, and it has a comprehensive genetic structure. This study was devoted to the analysis of lineages, which are defined based on COI gene sequences. Our new dataset was expanded by samples from freshwater basins of Northern and Central Eurasia. It allowed us to reveal a high level of genetic diversity for the widely distributed trans-Eurasian lineage of A. anatina for the first time. As for results, representative samples from the Russian Plain, Southern Siberia, and the Ural region showed the presence of multiple interactions between duck mussel populations, indicating the existence of connections between freshwater basins in this region during the Late Quaternary. The genetic group from the freshwater basins of Northern Eurasia may be divided into two sub-lineages, which have differences in genetic structure and distribution patterns. It was revealed that there was a post-glacial expansion of duck mussels in the freshwater basins of Northern Eurasia after deglaciations of these territories and that the wide distribution of this species in this region was shaped via ancient connections between periglacial waterbodies. The lineage of A. anatina from the Ponto-Caspian region is a genetically rich and diverged group, which is present in the riverine basins of West-Central Asia related to the Caspian Sea. Full article

(This article belongs to the Special Issue Systematics, Phylogeography, Evolution and Conservation of Molluscs)

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13 pages, 25399 KiB

Open AccessArticle

First Record of Corallivorous Nudibranch Pinufius (Gastropoda: Nudibranchia) in the South China Sea: A Suspected New Species of Pinufius

by Zhiyu Jia, Peng Tian, Wei Wang, Bingbing Cao, Ziqing Xu, Jiaguang Xiao and Wentao Niu

Diversity 2023, 15(2), 226; https://doi.org/10.3390/d15020226 - 04 Feb 2023

Cited by 1 | Viewed by 1479

Abstract

A corallivorous nudibranch from the South China Sea reproduced explosively and caused extensive damage to Porites in our aquarium. In this study, morphological and molecular analyses of the nudibranch were conducted and described. Morphologically, this nudibranch was nearly consistent with Pinufius rebus in [...] Read more.

A corallivorous nudibranch from the South China Sea reproduced explosively and caused extensive damage to Porites in our aquarium. In this study, morphological and molecular analyses of the nudibranch were conducted and described. Morphologically, this nudibranch was nearly consistent with Pinufius rebus in its characteristics intermediate between arminids and aeolids. The only detected difference was that the hook-like denticles on the masticatory border of P. rebus were absent in this nudibranch. In a molecular analysis, phylogenetic results based on the cytochrome oxidase subunit-I, 16S rRNA, and histone H3 gene sequences showed that this nudibranch and P. rebus form a well-supported sister clade under the superfamily Fionoidea, with significant interspecific divergence (0.18). Thus, we presumed that this nudibranch is a new species of Pinufius. Our results extend the distribution of Pinufius to the South China Sea, support the current taxonomic status of Pinufius under the superfamily Fionoidea, and imply that the species composition of Pinufius is more complex than previous records. Moreover, as a corallivorous nudibranch, the potential threat of Pinufius to coral health cannot be neglected. Full article

(This article belongs to the Special Issue Systematics, Phylogeography, Evolution and Conservation of Molluscs)

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25 pages, 5955 KiB

Open AccessArticle

Still Many to Be Named: An Integrative Analysis of the Genus Dendronotus (Gastropoda: Nudibranchia) in the North Pacific Revealed Seven New Species

by Irina A. Ekimova, Anna L. Mikhlina, Maria V. Stanovova, Nellya R. Krupitskaya, Olga V. Chichvarkhina and Dimitry M. Schepetov

Diversity 2023, 15(2), 162; https://doi.org/10.3390/d15020162 - 23 Jan 2023

Cited by 1 | Viewed by 1834

Abstract

In this paper, we report on the discovery of the hidden biodiversity of the genus Dendronotus (Gastropoda: Nudibranchia) in bathyal areas of the North Pacific (the Sea of Okhotsk and the Kuril Islands). We also test different scenarios of Dendronotus expansion to deeper [...] Read more.

In this paper, we report on the discovery of the hidden biodiversity of the genus Dendronotus (Gastropoda: Nudibranchia) in bathyal areas of the North Pacific (the Sea of Okhotsk and the Kuril Islands). We also test different scenarios of Dendronotus expansion to deeper waters. An integrative analysis was implemented based on morphological data (light microscopy and SEM) and molecular data, which included molecular phylogenetic analysis of four markers (COI, 16S, H3, and 28S), molecular species delimitation analyses, and ancestral area reconstruction. Our results indicated the presence of seven species new to science, five of which are described herein. The phylogenetic reconstructions show that these new species are members of different Dendronotus lineages. Ancestral area reconstruction indicates the shallow-water origin of the genus, while the invasion of deep waters occurs independently multiple times. Full article

(This article belongs to the Special Issue Systematics, Phylogeography, Evolution and Conservation of Molluscs)

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