Altai Pavón-Paneque, Enrique Ostalé-Valriberas, Free Espinosa, José Carlos García-Gómez
Patella ferruginea, an endemic marine mollusc of the western Mediterranean, faces a severe threat due to historical overexploitation, habitat loss and habitat vulnerability. This specie forms reproductive populations on sheltered dikes within Alboran Sea ports, presenting a persistent management challenge. Investigating both recruitment rates and preferences in artificial habitats, as well as early life stages, is crucial for its conservation. Three experiments, focusing on recruits under 25 mm, were conducted, with two exclusively in Ceuta's port in the Strait of Gibraltar. The first study explored intra-annual recruitment variations across three sites with different elevations (up, down) and inclinations (horizontal, vertical), utilizing fixed quadrats. Quadrats (20 × 20 cm) were surveyed for recruitment in March, April, May, July, October and December 2017. The second experiment, with similar factors, spanned 2017–2019, studying recruitment variations in March, May and July. The third examined the phoresy phenomenon—recruitment over conspecific shells—by comparing Ceuta and Melilla populations. Results revealed higher recruitment rates and smaller recruits in the lower midlittoral zone, followed by postrecruitment migration upwards. No discernible differences emerged regarding the slope or location for phoresy. This study highlights the potential of P. ferruginea recruitment data as an indicator of harbour health, acknowledging the influence of external factors on recruitment success. Long-term monitoring of recruitment patterns, alongside other ecological indicators, is crucial for informing sustainable management of P. ferruginea in port environments.
{"title":"Recruitment and phoresy of the endangered limpet Patella ferruginea in Ceuta (Strait of Gibraltar)","authors":"Altai Pavón-Paneque, Enrique Ostalé-Valriberas, Free Espinosa, José Carlos García-Gómez","doi":"10.1093/mollus/eyae018","DOIUrl":"https://doi.org/10.1093/mollus/eyae018","url":null,"abstract":"Patella ferruginea, an endemic marine mollusc of the western Mediterranean, faces a severe threat due to historical overexploitation, habitat loss and habitat vulnerability. This specie forms reproductive populations on sheltered dikes within Alboran Sea ports, presenting a persistent management challenge. Investigating both recruitment rates and preferences in artificial habitats, as well as early life stages, is crucial for its conservation. Three experiments, focusing on recruits under 25 mm, were conducted, with two exclusively in Ceuta's port in the Strait of Gibraltar. The first study explored intra-annual recruitment variations across three sites with different elevations (up, down) and inclinations (horizontal, vertical), utilizing fixed quadrats. Quadrats (20 × 20 cm) were surveyed for recruitment in March, April, May, July, October and December 2017. The second experiment, with similar factors, spanned 2017–2019, studying recruitment variations in March, May and July. The third examined the phoresy phenomenon—recruitment over conspecific shells—by comparing Ceuta and Melilla populations. Results revealed higher recruitment rates and smaller recruits in the lower midlittoral zone, followed by postrecruitment migration upwards. No discernible differences emerged regarding the slope or location for phoresy. This study highlights the potential of P. ferruginea recruitment data as an indicator of harbour health, acknowledging the influence of external factors on recruitment success. Long-term monitoring of recruitment patterns, alongside other ecological indicators, is crucial for informing sustainable management of P. ferruginea in port environments.","PeriodicalId":50126,"journal":{"name":"Journal of Molluscan Studies","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2024-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141502441","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The Conidae is a family of marine gastropod molluscs that includes carnivorous and venomous species. The venom they produce is remarkably diverse and has recently drawn much interest from a pharmacological perspective. To respond to this growing interest, a better understanding of the ecology and biology of the species is required. Only a few studies have examined the feeding behaviour and the trophic specialization of these species in detail. In this study, we investigated diet through hunger and satiety experiments of eight species of cones that occur in French Polynesia and that present different feeding modes (piscivorous, molluscivorous or vermivorous). Monitoring behaviour of cones during fasting periods demonstrated a correlation between increased hunger and nocturnal cone activity, mainly for piscivorous species, while the molluscivores did not show this correlation. In the study on satiety, we defined an average frequency of feeding for cone species that were fed prey ad libitum. Finally, this study provided indications that will help to define an equilibrium feeding frequency in further studies involving the cultivation of cones.
{"title":"Description of the feeding rhythm of cone snails in French Polynesia","authors":"Valentin Teillard, Camille Gache, Sebastien Dutertre, Tamatoa Bambridge, Bernard Salvat, Serge Planes","doi":"10.1093/mollus/eyae013","DOIUrl":"https://doi.org/10.1093/mollus/eyae013","url":null,"abstract":"The Conidae is a family of marine gastropod molluscs that includes carnivorous and venomous species. The venom they produce is remarkably diverse and has recently drawn much interest from a pharmacological perspective. To respond to this growing interest, a better understanding of the ecology and biology of the species is required. Only a few studies have examined the feeding behaviour and the trophic specialization of these species in detail. In this study, we investigated diet through hunger and satiety experiments of eight species of cones that occur in French Polynesia and that present different feeding modes (piscivorous, molluscivorous or vermivorous). Monitoring behaviour of cones during fasting periods demonstrated a correlation between increased hunger and nocturnal cone activity, mainly for piscivorous species, while the molluscivores did not show this correlation. In the study on satiety, we defined an average frequency of feeding for cone species that were fed prey ad libitum. Finally, this study provided indications that will help to define an equilibrium feeding frequency in further studies involving the cultivation of cones.","PeriodicalId":50126,"journal":{"name":"Journal of Molluscan Studies","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2024-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141153750","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Elizabeth A Bergey, Pongrat Dumrongrojwattana, Tuangthong Boonmachai, Nattawadee Nantarat
Biotic homogenization or the increasing similarity of biota has been documented in urban land snail assemblages in Europe and North America. The resulting biotic homogeneity is caused by a loss of native species and the establishment of non-native species. Climate affects land snail distributions, and because Thailand (exclusive of the southern peninsula) has an almost uniform climate, we hypothesized that urban land snail populations would show a high degree of taxonomic homogeneity. We sampled 76 sites (e.g. yards, temple grounds, restaurants and hotels) over a 38-day period during the rainy season in 2022. These sites included three regions: central (five provinces), north (two provinces) and northeast (five provinces). Both live snails and shells were counted, and the 10,470 counted individuals represented 25 taxa. Biotic homogeneity was indicated by three taxa comprising 69.9% of individuals. By far the most abundant species was the native species Sarika siamensis, which was found at all 76 sites and comprised 50.4% of all individuals. The other two abundant species were non-native species—the giant African snail Lissachatina fulica (60 sites) and Allopeas gracile (50 sites)—both widespread synanthropic species. Three other non-native species were also found. Among native species, slugs, including semislugs, were widespread but occurred in low numbers, and Pupina sp. occurred in high abundance (mean = 97 individuals/site) at 13 highly watered locations within its native range. Urban snail assemblages were not entirely homogeneous, as assemblages in the north region differed from those in the central and northeast regions. In conclusion, urban snail assemblages in Thailand showed a high degree of biotic homogeneity, in large part due to a native species, S. siamensis, indicating that native synanthropic species can contribute to biotic homogeneity.
{"title":"A native species contributes to biotic homogeneity of urban land snails in Thailand","authors":"Elizabeth A Bergey, Pongrat Dumrongrojwattana, Tuangthong Boonmachai, Nattawadee Nantarat","doi":"10.1093/mollus/eyae012","DOIUrl":"https://doi.org/10.1093/mollus/eyae012","url":null,"abstract":"Biotic homogenization or the increasing similarity of biota has been documented in urban land snail assemblages in Europe and North America. The resulting biotic homogeneity is caused by a loss of native species and the establishment of non-native species. Climate affects land snail distributions, and because Thailand (exclusive of the southern peninsula) has an almost uniform climate, we hypothesized that urban land snail populations would show a high degree of taxonomic homogeneity. We sampled 76 sites (e.g. yards, temple grounds, restaurants and hotels) over a 38-day period during the rainy season in 2022. These sites included three regions: central (five provinces), north (two provinces) and northeast (five provinces). Both live snails and shells were counted, and the 10,470 counted individuals represented 25 taxa. Biotic homogeneity was indicated by three taxa comprising 69.9% of individuals. By far the most abundant species was the native species Sarika siamensis, which was found at all 76 sites and comprised 50.4% of all individuals. The other two abundant species were non-native species—the giant African snail Lissachatina fulica (60 sites) and Allopeas gracile (50 sites)—both widespread synanthropic species. Three other non-native species were also found. Among native species, slugs, including semislugs, were widespread but occurred in low numbers, and Pupina sp. occurred in high abundance (mean = 97 individuals/site) at 13 highly watered locations within its native range. Urban snail assemblages were not entirely homogeneous, as assemblages in the north region differed from those in the central and northeast regions. In conclusion, urban snail assemblages in Thailand showed a high degree of biotic homogeneity, in large part due to a native species, S. siamensis, indicating that native synanthropic species can contribute to biotic homogeneity.","PeriodicalId":50126,"journal":{"name":"Journal of Molluscan Studies","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2024-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141062568","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The sex ratio is nearly equal in most organisms, while several ecological and evolutionary factors skew the sex ratio. We evaluated the sex ratios of 12 species in the freshwater snail genus Semisulcospira in and around Lake Biwa. We found highly female-biased sex ratios in all 12 species. The sex ratios were nearly equal or slightly female-biased in the smaller shell-size classes, while they were highly female-biased in the larger size classes. We also found that females were significantly larger in most of these species. Further, the species with a larger size difference between the sexes tended to exhibit a more female-biased sex ratio. Considering the general correlation between shell size and age, this pattern can be explained by longer lifespans in females, shaping the observed female-biased sex ratios. We also found that some Semisulcospira species showed female-biased sex ratios in all shell size classes. This pattern suggests that the distinct longevity hypothesis can not solely explain the observed biased sex ratios. We discussed the possible contributions of the sampling errors and selfish genetic elements to the observed biased sex ratios. This study provides essential information to disentangle the mechanisms of the biased sex ratio in the Semisulcospira snails.
{"title":"Highly biased sex ratios in the twelve species of the freshwater snail genus Semisulcospira in and around Lake Biwa","authors":"Kanta Hamazaki, Osamu Miura","doi":"10.1093/mollus/eyae011","DOIUrl":"https://doi.org/10.1093/mollus/eyae011","url":null,"abstract":"The sex ratio is nearly equal in most organisms, while several ecological and evolutionary factors skew the sex ratio. We evaluated the sex ratios of 12 species in the freshwater snail genus Semisulcospira in and around Lake Biwa. We found highly female-biased sex ratios in all 12 species. The sex ratios were nearly equal or slightly female-biased in the smaller shell-size classes, while they were highly female-biased in the larger size classes. We also found that females were significantly larger in most of these species. Further, the species with a larger size difference between the sexes tended to exhibit a more female-biased sex ratio. Considering the general correlation between shell size and age, this pattern can be explained by longer lifespans in females, shaping the observed female-biased sex ratios. We also found that some Semisulcospira species showed female-biased sex ratios in all shell size classes. This pattern suggests that the distinct longevity hypothesis can not solely explain the observed biased sex ratios. We discussed the possible contributions of the sampling errors and selfish genetic elements to the observed biased sex ratios. This study provides essential information to disentangle the mechanisms of the biased sex ratio in the Semisulcospira snails.","PeriodicalId":50126,"journal":{"name":"Journal of Molluscan Studies","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2024-05-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140934085","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Diana Delicado, Jonathan P Miller, Fernando García-Guerrero, Beatriz Arconada, Marian A Ramos
Multilocus phylogenies have shown that soft-part anatomy alone is insufficient for the systematics of valvatiform- and trochiform-shelled springsnails of the subfamily Islamiinae (family Hydrobiidae) due to morphological similarities between taxa that are not closely related. However, a solid knowledge of their systematics and species boundaries is crucial to conserve this highly imperilled group. Here, we inferred molecular phylogenies based on two mitochondrial and two nuclear gene fragments from representatives of three morphological species of the Iberian genus Iberhoratia and performed multispecies coalescent and shell variation analyses (geometric morphometrics) to reevaluate their taxonomic status. The resulting phylogenetic analyses, which included homologous sequences of 15 other valvatiform-shelled hydrobiid species endemic to the Iberian Peninsula, depicted the topotypical specimens of I. aurorae and I. gatoa elisai distantly related to one another and the type species I. morenoi. Considering their high genetic divergence and morphological differences from other hydrobiid taxa, we have placed the former two species in the new genera Beatrix n. gen. and Actenidia n. gen. The multispecies coalescent delimitation method DELINEATE, a novel approach to the taxonomy of the Hydrobiidae, and shell morphometric data suggested two species within the ‘I. gatoa elisai’ clade. Based on morphological and molecular evidence, we recognized this clade as Actenidia, a new genus comprising the species A. elisai n. gen., n. comb. and A. baetica n. gen., n. sp. Our results underscore the importance of using multiple lines of evidence to delimitate species of Islamiinae and interpret their systematics. We also discuss the implications of our findings for conserving I. gatoa.
多焦点系统进化研究表明，由于形态上的相似性，单凭软体解剖学不足以对伊斯兰亚科（水螅科）的瓣状壳和蝶状壳萌甲进行系统学研究。然而，对其系统学和物种边界的扎实了解对于保护这一濒临灭绝的族群至关重要。在这里，我们根据伊比利亚属三个形态物种代表的两个线粒体基因片段和两个核基因片段推断了分子系统发生，并进行了多物种凝聚和贝壳变异分析（几何形态计量学），以重新评估它们的分类地位。系统进化分析结果显示，I. aurorae 和 I. gatoa elisai 的顶型标本与模式种 I. morenoi 之间的亲缘关系较远。考虑到它们与其他水生类群的高度遗传差异和形态差异，我们将前两个物种归入新属 Beatrix n. gen. 和 Actenidia n. gen.多物种共聚划界法 DELINEATE 是水生生物科分类学的一种新方法，贝壳形态数据表明 "I. gatoa elisai "支系中有两个物种。基于形态学和分子证据，我们将该支系认定为Actenidia，这是一个新属，由A. elisai n. gen., n. comb. 和A. baetica n. gen., n. sp.两个种组成。我们还讨论了我们的发现对保护 I. gatoa 的影响。
{"title":"DNA sequence data, multispecies coalescent and morphometrics shed new light on the systematics of Iberian islamiinae springsnails (Caenogastropoda: Hydrobiidae)","authors":"Diana Delicado, Jonathan P Miller, Fernando García-Guerrero, Beatriz Arconada, Marian A Ramos","doi":"10.1093/mollus/eyae006","DOIUrl":"https://doi.org/10.1093/mollus/eyae006","url":null,"abstract":"Multilocus phylogenies have shown that soft-part anatomy alone is insufficient for the systematics of valvatiform- and trochiform-shelled springsnails of the subfamily Islamiinae (family Hydrobiidae) due to morphological similarities between taxa that are not closely related. However, a solid knowledge of their systematics and species boundaries is crucial to conserve this highly imperilled group. Here, we inferred molecular phylogenies based on two mitochondrial and two nuclear gene fragments from representatives of three morphological species of the Iberian genus Iberhoratia and performed multispecies coalescent and shell variation analyses (geometric morphometrics) to reevaluate their taxonomic status. The resulting phylogenetic analyses, which included homologous sequences of 15 other valvatiform-shelled hydrobiid species endemic to the Iberian Peninsula, depicted the topotypical specimens of I. aurorae and I. gatoa elisai distantly related to one another and the type species I. morenoi. Considering their high genetic divergence and morphological differences from other hydrobiid taxa, we have placed the former two species in the new genera Beatrix n. gen. and Actenidia n. gen. The multispecies coalescent delimitation method DELINEATE, a novel approach to the taxonomy of the Hydrobiidae, and shell morphometric data suggested two species within the ‘I. gatoa elisai’ clade. Based on morphological and molecular evidence, we recognized this clade as Actenidia, a new genus comprising the species A. elisai n. gen., n. comb. and A. baetica n. gen., n. sp. Our results underscore the importance of using multiple lines of evidence to delimitate species of Islamiinae and interpret their systematics. We also discuss the implications of our findings for conserving I. gatoa.","PeriodicalId":50126,"journal":{"name":"Journal of Molluscan Studies","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2024-04-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140592847","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sarah M Boomer, Michael J Baltzley, Bryan E Dutton, Parker N Smith
The Pacific banana slug, Ariolimax columbianus, is the largest land mollusc in North America and occurs in forests ranging from northwestern California to Alaska. We explored the microbial community found within the faeces of 24 slugs from the Oregon Coast Range. Twenty-four slugs were collected in 2019, 12 in the spring and 12 in the fall. These two time points were selected to investigate the composition of microbial populations in wild-caught slugs, also in response to seasonal changes in available plants as food sources. Results from 16S rRNA gene amplicon sequencing indicate that the most prevalent phyla detected from A. columbianus were Proteobacteria (66%) and Bacteriodetes (16%), similar to previous observations from six other species/genera of terrestrial gastropods (Stylommatophora). The most abundant operational taxonomic units across all specimens were Enterobacter sp., Pseudomonas sp. and Flavobacterium sp. Significant seasonal variation was observed for several species of Flavobacteriales, Firmicutes and Proteobacteria, with the majority showing higher abundance in fall. In contrast to Cornu aspersum (previously Helix aspersa, parapatric with A. columbianus) and Geomaculus maculosus, A. columbianus harbours very low levels of Buttiauxella (0.35%). These findings raise questions about the origin, specificity and selection of specific bacteria as components of the intestinal microbiome of terrestrial gastropods.
{"title":"The faecal microbiome of the Pacific banana slug, Ariolimax columbianus, displays seasonal variation","authors":"Sarah M Boomer, Michael J Baltzley, Bryan E Dutton, Parker N Smith","doi":"10.1093/mollus/eyae007","DOIUrl":"https://doi.org/10.1093/mollus/eyae007","url":null,"abstract":"The Pacific banana slug, Ariolimax columbianus, is the largest land mollusc in North America and occurs in forests ranging from northwestern California to Alaska. We explored the microbial community found within the faeces of 24 slugs from the Oregon Coast Range. Twenty-four slugs were collected in 2019, 12 in the spring and 12 in the fall. These two time points were selected to investigate the composition of microbial populations in wild-caught slugs, also in response to seasonal changes in available plants as food sources. Results from 16S rRNA gene amplicon sequencing indicate that the most prevalent phyla detected from A. columbianus were Proteobacteria (66%) and Bacteriodetes (16%), similar to previous observations from six other species/genera of terrestrial gastropods (Stylommatophora). The most abundant operational taxonomic units across all specimens were Enterobacter sp., Pseudomonas sp. and Flavobacterium sp. Significant seasonal variation was observed for several species of Flavobacteriales, Firmicutes and Proteobacteria, with the majority showing higher abundance in fall. In contrast to Cornu aspersum (previously Helix aspersa, parapatric with A. columbianus) and Geomaculus maculosus, A. columbianus harbours very low levels of Buttiauxella (0.35%). These findings raise questions about the origin, specificity and selection of specific bacteria as components of the intestinal microbiome of terrestrial gastropods.","PeriodicalId":50126,"journal":{"name":"Journal of Molluscan Studies","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2024-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140592836","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Many gastropods have columellar folds, defined as continuous spiral ridges extending from the aperture to the shell interior on the adaxial side of the aperture. Despite their ubiquity, columellar folds have received little phylogenetic or functional study. In the vast majority of cases, columellar folds have a symmetrical profile, with the anterior (abapical) slope similar to the posterior (adapical) slope. Here I draw attention to the highly unusual phenomenon of asymmetry of columellar folds, where the anterior slope is markedly less inclined than the posterior slope of each fold. I have detected this condition in the volutid genera Scaphella Swainson, 1832; Cymbiola Swainson, 1831 and Lyrischapa Aldrich, 1911; as well as in the Palaeocene and Eocene genus Eovasum Douvillé, 1920. Following a review of Lyrischapa and Eovasum, I suggest that these two genera are closely related members of the volutid subfamily Indovolutinae, and that asymmetrical columellar folds have evolved three times in Volutidae. Although their function remains elusive, asymmetrical folds might prevent abapical displacement of the soft parts during rapid extension of the foot or feeding organs.
{"title":"Overlooked shell features: asymmetrical columellar folds in volutid gastropods","authors":"Geerat J Vermeij","doi":"10.1093/mollus/eyae004","DOIUrl":"https://doi.org/10.1093/mollus/eyae004","url":null,"abstract":"Many gastropods have columellar folds, defined as continuous spiral ridges extending from the aperture to the shell interior on the adaxial side of the aperture. Despite their ubiquity, columellar folds have received little phylogenetic or functional study. In the vast majority of cases, columellar folds have a symmetrical profile, with the anterior (abapical) slope similar to the posterior (adapical) slope. Here I draw attention to the highly unusual phenomenon of asymmetry of columellar folds, where the anterior slope is markedly less inclined than the posterior slope of each fold. I have detected this condition in the volutid genera Scaphella Swainson, 1832; Cymbiola Swainson, 1831 and Lyrischapa Aldrich, 1911; as well as in the Palaeocene and Eocene genus Eovasum Douvillé, 1920. Following a review of Lyrischapa and Eovasum, I suggest that these two genera are closely related members of the volutid subfamily Indovolutinae, and that asymmetrical columellar folds have evolved three times in Volutidae. Although their function remains elusive, asymmetrical folds might prevent abapical displacement of the soft parts during rapid extension of the foot or feeding organs.","PeriodicalId":50126,"journal":{"name":"Journal of Molluscan Studies","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2024-03-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140197538","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Mucus is a defining feature of many gastropod phenotypes. Its material properties are a product of selection acting on the relationship between mucus composition, structure and performance; however, to date, there are very few studies addressing this. Here, we introduce attenuated total reflection Fourier transform infrared (FTIR) spectroscopy as an accessible analytical technique to record, identify and classify gastropod locomotive mucus, as deposited, with practically no intervention. Advancing the field beyond previous spectroscopic studies, we also probe mucus response to a temperature increase, determining its propensity to remain hydrated (i.e. resist denaturation) and serving as the basis for building cladograms based on spectral similarities. Specifically, the relative content of proteins, their secondary structures, protein-carbohydrate interactions, and thermal stability were investigated and shown to have significant variation between species. Collating and comparing over 648 spectra across 12 species and 7 superfamilies, we report that it is even possible to classify gastropods based solely on their secreted pedal mucus. This was further compared to previously published phylogenetic data and taxonomies enabling a 100% hit rate of genus assignment, implying that mucus FTIR may also be a powerful tool for field-based biodiversity studies.
{"title":"Analysis, classification and identification of gastropod locomotive mucus by Fourier transform infrared spectroscopy","authors":"Edgar Barajas Ledesma, Chris Holland","doi":"10.1093/mollus/eyae005","DOIUrl":"https://doi.org/10.1093/mollus/eyae005","url":null,"abstract":"Mucus is a defining feature of many gastropod phenotypes. Its material properties are a product of selection acting on the relationship between mucus composition, structure and performance; however, to date, there are very few studies addressing this. Here, we introduce attenuated total reflection Fourier transform infrared (FTIR) spectroscopy as an accessible analytical technique to record, identify and classify gastropod locomotive mucus, as deposited, with practically no intervention. Advancing the field beyond previous spectroscopic studies, we also probe mucus response to a temperature increase, determining its propensity to remain hydrated (i.e. resist denaturation) and serving as the basis for building cladograms based on spectral similarities. Specifically, the relative content of proteins, their secondary structures, protein-carbohydrate interactions, and thermal stability were investigated and shown to have significant variation between species. Collating and comparing over 648 spectra across 12 species and 7 superfamilies, we report that it is even possible to classify gastropods based solely on their secreted pedal mucus. This was further compared to previously published phylogenetic data and taxonomies enabling a 100% hit rate of genus assignment, implying that mucus FTIR may also be a powerful tool for field-based biodiversity studies.","PeriodicalId":50126,"journal":{"name":"Journal of Molluscan Studies","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2024-03-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140099728","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this paper, a new genus in the nudibranch family Discodorididae, Avaldesia n. gen., is established for Avaldesia albomacula (Chan & Gosliner, 2007) and Avaldesia tahala (Chan & Gosliner, 2007), originally assigned to the genus Thordisa Bergh, 1877, and a new species, Avaldesia tamatoa n. sp., described here from the central Pacific. To establish species relationships within Avaldesia, as well as the placement of Avaldesia within Discodorididae, we utilized four molecular markers (cytochrome c oxidase subunit I, 16S rRNA, histone H3 and 28S rRNA) in our Bayesian inference and maximum likelihood analyses. Four species delimitation methods were complemented by morphological dissections and scanning electron microscopy. Our results reveal a clear separation between Avaldesia and Thordisa and suggest that Avaldesia is more closely related to the genera Hoplodoris Bergh, 1880 and Asteronotus Ehrenberg, 1831. The most characteristic features of Avaldesia include a radula with increasing denticulation towards the fimbriate outermost laterals and a reproductive system with a lobate vestibular gland, occasional hollow vestibular spine and a penis armed with one or more penial spines. All species of Avaldesia are found in shallow water (5–10 m depth) on rocky reefs, sandy sediments and algal fields with distributions across the Indo-Pacific.
{"title":"Variability in the white spot: a new genus and species of Discodorididae (Nudibranchia) from the central and western Pacific Ocean","authors":"Samantha A Donohoo, Terrence M Gosliner","doi":"10.1093/mollus/eyad027","DOIUrl":"https://doi.org/10.1093/mollus/eyad027","url":null,"abstract":"In this paper, a new genus in the nudibranch family Discodorididae, Avaldesia n. gen., is established for Avaldesia albomacula (Chan & Gosliner, 2007) and Avaldesia tahala (Chan & Gosliner, 2007), originally assigned to the genus Thordisa Bergh, 1877, and a new species, Avaldesia tamatoa n. sp., described here from the central Pacific. To establish species relationships within Avaldesia, as well as the placement of Avaldesia within Discodorididae, we utilized four molecular markers (cytochrome c oxidase subunit I, 16S rRNA, histone H3 and 28S rRNA) in our Bayesian inference and maximum likelihood analyses. Four species delimitation methods were complemented by morphological dissections and scanning electron microscopy. Our results reveal a clear separation between Avaldesia and Thordisa and suggest that Avaldesia is more closely related to the genera Hoplodoris Bergh, 1880 and Asteronotus Ehrenberg, 1831. The most characteristic features of Avaldesia include a radula with increasing denticulation towards the fimbriate outermost laterals and a reproductive system with a lobate vestibular gland, occasional hollow vestibular spine and a penis armed with one or more penial spines. All species of Avaldesia are found in shallow water (5–10 m depth) on rocky reefs, sandy sediments and algal fields with distributions across the Indo-Pacific.","PeriodicalId":50126,"journal":{"name":"Journal of Molluscan Studies","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2024-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139760585","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
John Buckland-Nicks, Arkadiy Reunov, Olga Yurchenko
Fifty years ago, it was reported that individuals of the Pacific boreal limpet Problacmaea (= Erginus) bear a penis for copulation and brood their young in the pallial cavity. These observations were based on light microscopy, but now we reveal new details of the reproductive biology of Erginus (Problacmaea) puniceus with electron microscopy. Gametogenesis is fundamentally similar to other Patellogastropoda, but there are some key differences. Oocytes develop in the ovary, dorsal to the foot in the posterior half of the body, before passing through the oviduct to the pallial cavity, where they are fertilized and brooded. Development is direct with embryos being brooded to the crawl-away juvenile stage. However, sometimes fertilization occurs internally with embryos beginning development in or near the gonad. Free sperm, which were likely autosperm (self) but could have been allosperm (cross), were found near developing oocytes in the gonad. Spermiogenesis results in the formation of an enta-quasperm with a cap-like acrosome, a bullet-shaped nucleus and spherical mitochondria in the midpiece. Copulation was not observed, but we confirm the presence of a penis with a dorsal penial groove that lies below the right cephalic tentacle in males, which is typical of functional penises of some molluscs. Males were always smaller, but intermediate-sized individuals were hermaphroditic to different extents. The largest individuals were entirely female, and their penises were smaller and often lacked the penial groove. Thus, E. (Problacmaea) puniceus appears to be a protandrous hermaphrodite, passing from male to female phase. Remnants of the testis persist into the female phase, suggesting that they are protandrous hermaphrodites with overlap, possibly allowing for self-fertilization to occur on occasion. However, the largest females lacked any testis remnants, suggesting instead that the species may be protandrous sequential hermaphrodites.
{"title":"On reproduction in the Pacific boreal limpet Erginus (Problacmaea) puniceus Lindberg, 1988 (Patellogastropoda: Rhodopetalidae)","authors":"John Buckland-Nicks, Arkadiy Reunov, Olga Yurchenko","doi":"10.1093/mollus/eyad023","DOIUrl":"https://doi.org/10.1093/mollus/eyad023","url":null,"abstract":"Fifty years ago, it was reported that individuals of the Pacific boreal limpet Problacmaea (= Erginus) bear a penis for copulation and brood their young in the pallial cavity. These observations were based on light microscopy, but now we reveal new details of the reproductive biology of Erginus (Problacmaea) puniceus with electron microscopy. Gametogenesis is fundamentally similar to other Patellogastropoda, but there are some key differences. Oocytes develop in the ovary, dorsal to the foot in the posterior half of the body, before passing through the oviduct to the pallial cavity, where they are fertilized and brooded. Development is direct with embryos being brooded to the crawl-away juvenile stage. However, sometimes fertilization occurs internally with embryos beginning development in or near the gonad. Free sperm, which were likely autosperm (self) but could have been allosperm (cross), were found near developing oocytes in the gonad. Spermiogenesis results in the formation of an enta-quasperm with a cap-like acrosome, a bullet-shaped nucleus and spherical mitochondria in the midpiece. Copulation was not observed, but we confirm the presence of a penis with a dorsal penial groove that lies below the right cephalic tentacle in males, which is typical of functional penises of some molluscs. Males were always smaller, but intermediate-sized individuals were hermaphroditic to different extents. The largest individuals were entirely female, and their penises were smaller and often lacked the penial groove. Thus, E. (Problacmaea) puniceus appears to be a protandrous hermaphrodite, passing from male to female phase. Remnants of the testis persist into the female phase, suggesting that they are protandrous hermaphrodites with overlap, possibly allowing for self-fertilization to occur on occasion. However, the largest females lacked any testis remnants, suggesting instead that the species may be protandrous sequential hermaphrodites.","PeriodicalId":50126,"journal":{"name":"Journal of Molluscan Studies","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2024-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139583254","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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