Sacoglossan sea slugs have developed a variety of defence mechanisms against predation. Research on these mechanisms has focused primarily on the chemical defences of these slugs, and little information is available on nonchemical modes of defence, such as autotomy, a behaviour in which an organism voluntarily detaches body structures at a predetermined breakage point in response to danger or stress. Autotomy is diverse in sacoglossan sea slugs and has been well documented. Within Oxynidae, members can autotomize their tail and parapodial lobes, and slugs in Limapontiidae and Hermaeidae can detach their cerata. More recently, reports have been made of Elysia with the capacity to autotomize most of their body. However, despite the widespread assumption that autotomy in this group serves a defensive purpose, the effectiveness of the behaviour in ensuring survival against predation has seldom been examined. The objective of this study was to evaluate the role of autotomy in sacoglossans by assessing the effectiveness of ceratal autotomy in ensuring survival against the attacks of a generalist predator. Placida kingstoni is a small sacoglossan native to Florida and the Caribbean with the ability to autotomize its cerata. Individual P. kingstoni were exposed to shrimps of the Lysmata wurdemanni species complex for 10-min interactions. Most sea slugs were attacked by the predator, often more than once, but the majority of the slugs readily autotomized cerata and survived. Structure detachment was accompanied by the secretion of a mucus that facilitated the formation of ceratal clumps. Most of these clumps were consumed by the predator and effectively diverted their attention, allowing P. kingstoni to crawl away. In this species, the success of autotomy as a defensive strategy appears to be directly related to the palatability of autotomized cerata. The results of this study show that ceratal autotomy in P. kingstoni is an effective defence against predation. Autotomy is a behaviour with a high-energetic cost; however, it has convergently evolved within Heterobranchia on multiple occasions, and it is highly prevalent in cerata-bearing slugs. Although in sacoglossans much of this behaviour remains a mystery, this study provides a clear example of autotomy as a defensive mechanism.
{"title":"Ceratal autotomy as a defensive mechanism of the sacoglossan sea slug Placida kingstoni against a generalist crustacean predator","authors":"D. Gutierrez-Andrade, M. Middlebrooks","doi":"10.1093/mollus/eyad013","DOIUrl":"https://doi.org/10.1093/mollus/eyad013","url":null,"abstract":"\u0000 Sacoglossan sea slugs have developed a variety of defence mechanisms against predation. Research on these mechanisms has focused primarily on the chemical defences of these slugs, and little information is available on nonchemical modes of defence, such as autotomy, a behaviour in which an organism voluntarily detaches body structures at a predetermined breakage point in response to danger or stress. Autotomy is diverse in sacoglossan sea slugs and has been well documented. Within Oxynidae, members can autotomize their tail and parapodial lobes, and slugs in Limapontiidae and Hermaeidae can detach their cerata. More recently, reports have been made of Elysia with the capacity to autotomize most of their body. However, despite the widespread assumption that autotomy in this group serves a defensive purpose, the effectiveness of the behaviour in ensuring survival against predation has seldom been examined. The objective of this study was to evaluate the role of autotomy in sacoglossans by assessing the effectiveness of ceratal autotomy in ensuring survival against the attacks of a generalist predator. Placida kingstoni is a small sacoglossan native to Florida and the Caribbean with the ability to autotomize its cerata. Individual P. kingstoni were exposed to shrimps of the Lysmata wurdemanni species complex for 10-min interactions. Most sea slugs were attacked by the predator, often more than once, but the majority of the slugs readily autotomized cerata and survived. Structure detachment was accompanied by the secretion of a mucus that facilitated the formation of ceratal clumps. Most of these clumps were consumed by the predator and effectively diverted their attention, allowing P. kingstoni to crawl away. In this species, the success of autotomy as a defensive strategy appears to be directly related to the palatability of autotomized cerata. The results of this study show that ceratal autotomy in P. kingstoni is an effective defence against predation. Autotomy is a behaviour with a high-energetic cost; however, it has convergently evolved within Heterobranchia on multiple occasions, and it is highly prevalent in cerata-bearing slugs. Although in sacoglossans much of this behaviour remains a mystery, this study provides a clear example of autotomy as a defensive mechanism.","PeriodicalId":50126,"journal":{"name":"Journal of Molluscan Studies","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2023-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46932538","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}
{"title":"The introduced land snail Tanychlamys indica preys on live land snails","authors":"T. Hirano, M. Tatani, S. Ito, K. Kudo, S. Wada","doi":"10.1093/mollus/eyad010","DOIUrl":"https://doi.org/10.1093/mollus/eyad010","url":null,"abstract":"","PeriodicalId":50126,"journal":{"name":"Journal of Molluscan Studies","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2023-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42560219","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}
Invasive snails, Cernuella virgata, Theba pisana and Cochlicella acuta, infest grain crops prior to harvest in early summer in southern Australia. They breed in autumn–early winter and peak in abundance in spring following the recruitment of young snails. Long-term studies (20 years) were established on three farms in South Australia (two practicing pasture–cereal rotations and one continuous cropping) to better understand the role of prevailing weather in driving the population dynamics of the three snail species and to develop predictive models that might assist farmers and off-farm grain handlers to anticipate future peaks in snail abundance and tailor their management practices accordingly. The three species are asynchronous in their population dynamics; they peak in numbers in different years. The abundance of C. virgata in late spring (preharvest) was most closely associated with, and could be broadly predicted by, the previous autumn to spring rainfall, but no significant associations were found between the rainfall and the abundance of C. acuta and T. pisana. Local air temperatures had little apparent association with the abundance of all three species. Broader scale weather, exemplified by the El Niño Southern Oscillation Index, was only occasionally, and weakly, related to the spring abundance of C. virgata.
{"title":"Long-term relationships between the abundance of pest molluscs and weather in agricultural fields in South Australia","authors":"G. Baker","doi":"10.1093/mollus/eyad009","DOIUrl":"https://doi.org/10.1093/mollus/eyad009","url":null,"abstract":"\u0000 Invasive snails, Cernuella virgata, Theba pisana and Cochlicella acuta, infest grain crops prior to harvest in early summer in southern Australia. They breed in autumn–early winter and peak in abundance in spring following the recruitment of young snails. Long-term studies (20 years) were established on three farms in South Australia (two practicing pasture–cereal rotations and one continuous cropping) to better understand the role of prevailing weather in driving the population dynamics of the three snail species and to develop predictive models that might assist farmers and off-farm grain handlers to anticipate future peaks in snail abundance and tailor their management practices accordingly. The three species are asynchronous in their population dynamics; they peak in numbers in different years. The abundance of C. virgata in late spring (preharvest) was most closely associated with, and could be broadly predicted by, the previous autumn to spring rainfall, but no significant associations were found between the rainfall and the abundance of C. acuta and T. pisana. Local air temperatures had little apparent association with the abundance of all three species. Broader scale weather, exemplified by the El Niño Southern Oscillation Index, was only occasionally, and weakly, related to the spring abundance of C. virgata.","PeriodicalId":50126,"journal":{"name":"Journal of Molluscan Studies","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2023-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42655457","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}
Left–right asymmetries are consistent differences between the left and right sides and represent an intriguing feature of molluscan morphology. Interestingly, external asymmetries, such as inequivalve shells, are often coupled with lateralization in the nervous system, which often includes functional and structural specializations of the left or right sides. In the case of visual asymmetries, lateralized phenotypes frequently include left–right differences in eye position, structure and use. To investigate lateralization and visual asymmetries among bivalves, we examined the visual and nervous systems of the scallop Nodipecten nodosus. We characterized different eye morphologies in the species and determined eye-side frequencies. We also studied the anatomy of the nervous system, focusing on the parietovisceral ganglion (PVG). Our results reveal that the visual and nervous systems of the scallop N. nodosus comprise consistent left–right asymmetries: (1) a greater number of eyes on the left side, (2) increased size of the left PVG lateral lobe, (3) larger glomeruli in the left PVG lateral lobe and (4) radial pallial nerves associated with the left lateral lobe spaced more widely than the more compactly arranged pallial nerves associated with the right lateral lobe. In addition, eyes with a distinctive morphology, where the optic vesicle is rotated, are more frequent on the left side. Considering the habit of this species to rest on the right valve, we hypothesize that curved eyes might contribute to expanding the overall visual field. Even though bivalves are not typically considered in the literature on lateralization, accumulating evidence for scallops, as suggested by our results, indicates their potential to reveal novel patterns of visual asymmetry in benthic invertebrates.
{"title":"Left–right asymmetry of the visual system in the scallop Nodipecten nodosus (Bivalvia: Pectinidae)","authors":"J. A. Audino, J. Serb, J. Marian","doi":"10.1093/mollus/eyad007","DOIUrl":"https://doi.org/10.1093/mollus/eyad007","url":null,"abstract":"\u0000 Left–right asymmetries are consistent differences between the left and right sides and represent an intriguing feature of molluscan morphology. Interestingly, external asymmetries, such as inequivalve shells, are often coupled with lateralization in the nervous system, which often includes functional and structural specializations of the left or right sides. In the case of visual asymmetries, lateralized phenotypes frequently include left–right differences in eye position, structure and use. To investigate lateralization and visual asymmetries among bivalves, we examined the visual and nervous systems of the scallop Nodipecten nodosus. We characterized different eye morphologies in the species and determined eye-side frequencies. We also studied the anatomy of the nervous system, focusing on the parietovisceral ganglion (PVG). Our results reveal that the visual and nervous systems of the scallop N. nodosus comprise consistent left–right asymmetries: (1) a greater number of eyes on the left side, (2) increased size of the left PVG lateral lobe, (3) larger glomeruli in the left PVG lateral lobe and (4) radial pallial nerves associated with the left lateral lobe spaced more widely than the more compactly arranged pallial nerves associated with the right lateral lobe. In addition, eyes with a distinctive morphology, where the optic vesicle is rotated, are more frequent on the left side. Considering the habit of this species to rest on the right valve, we hypothesize that curved eyes might contribute to expanding the overall visual field. Even though bivalves are not typically considered in the literature on lateralization, accumulating evidence for scallops, as suggested by our results, indicates their potential to reveal novel patterns of visual asymmetry in benthic invertebrates.","PeriodicalId":50126,"journal":{"name":"Journal of Molluscan Studies","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2023-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46956366","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 egg mass fluid (EMF) of the freshwater snail Biomphalaria glabrata (Hygrophila: Planorbidae) contains haemocyanin-like 1 (Hcl-1) protein, distinct from respiratory haemocyanins. The distribution of Hcl-1 was investigated among major families of Hygrophila, Physidae and Lymnaeidae, both of which employ respiratory haemocyanins, and Planorbidae, a group that evolved haemoglobin as a respiratory pigment. Immunoblotting detected c. 150 kDa protein (molecular weight of Hcl-1) cross-reactive with anti-keyhole limpet haemocyanin antiserum in the EMF of planorbids Bulinus globosus and Planorbella duryi (from a genus closely related to Biomphalaria), but not Physella acuta (Physidae) and Ladislavella elodes (Lymnaeidae). High throughput sequence data revealed Hcl-1 homologs from Bulinus globosus and Planorbella duryi, representative species that span the range of planorbid phylogeny, but not from Physella acuta (Physidae) and Lymnaea stagnalis (Lymnaeidae). A domain architecture comprising only three functional units (FUs) and predicted secondary structures within the C-terminal FU distinguish planorbid Hcl-1 protein from molluscan respiratory haemocyanins that are natively assembled as functional didecamers. Immunoblotting confirmed a monomeric configuration of native Hcl-1. Molecular clock analysis estimated divergence of Hcl-1 proteins from gastropod respiratory haemocyanins at 267 ± 143 Ma. It is hypothesized that Hcl proteins originated in the ancestor of the planorbid lineage when evolution of respiratory haemoglobin altered selective pressures for maintaining original function, facilitating mutation and refunctionalization of the ancestral respiratory haemocyanin in Planorbidae.
{"title":"Comparative analysis of three families of hygrophilid snails shows that the egg mass fluid protein haemocyanin-like 1 (Hcl-1) is unique to planorbids","authors":"Janeth J. Peña, E. Loker, C. Adema","doi":"10.1093/mollus/eyad006","DOIUrl":"https://doi.org/10.1093/mollus/eyad006","url":null,"abstract":"\u0000 The egg mass fluid (EMF) of the freshwater snail Biomphalaria glabrata (Hygrophila: Planorbidae) contains haemocyanin-like 1 (Hcl-1) protein, distinct from respiratory haemocyanins. The distribution of Hcl-1 was investigated among major families of Hygrophila, Physidae and Lymnaeidae, both of which employ respiratory haemocyanins, and Planorbidae, a group that evolved haemoglobin as a respiratory pigment. Immunoblotting detected c. 150 kDa protein (molecular weight of Hcl-1) cross-reactive with anti-keyhole limpet haemocyanin antiserum in the EMF of planorbids Bulinus globosus and Planorbella duryi (from a genus closely related to Biomphalaria), but not Physella acuta (Physidae) and Ladislavella elodes (Lymnaeidae). High throughput sequence data revealed Hcl-1 homologs from Bulinus globosus and Planorbella duryi, representative species that span the range of planorbid phylogeny, but not from Physella acuta (Physidae) and Lymnaea stagnalis (Lymnaeidae). A domain architecture comprising only three functional units (FUs) and predicted secondary structures within the C-terminal FU distinguish planorbid Hcl-1 protein from molluscan respiratory haemocyanins that are natively assembled as functional didecamers. Immunoblotting confirmed a monomeric configuration of native Hcl-1. Molecular clock analysis estimated divergence of Hcl-1 proteins from gastropod respiratory haemocyanins at 267 ± 143 Ma. It is hypothesized that Hcl proteins originated in the ancestor of the planorbid lineage when evolution of respiratory haemoglobin altered selective pressures for maintaining original function, facilitating mutation and refunctionalization of the ancestral respiratory haemocyanin in Planorbidae.","PeriodicalId":50126,"journal":{"name":"Journal of Molluscan Studies","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2023-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44247674","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}
Sofía Paz-Sedano, D. Smirnoff, T. Gosliner, M. Pola
Goniodoris is the third most diverse genus of the nudibranch family Goniodorididae. The genus has undergone several taxonomic changes, with c. one-third of the recognized species of Goniodoris having been synonymized (most of these are junior synonyms of genera from other families). In addition, Goniodoris includes other synonymized genera within it, such as Pelagella, which was erected for Doris pareti. This species was synonymized with Goniodoris castanea and the genus Pelagella went almost unnoticed. In the present study, we investigate the systematics of the genus Goniodoris by examining specimens of G. castanea from England and Spain, G. joubini from Hawaii and six undescribed Goniodoris species from Australia, the Philippines and Mozambique. The morphology of the new species is studied using dissections of the internal organs and scanning electron micrographs of the radulae, labial cuticles and the penis. We also carried out phylogenetic analyses using partial DNA sequences of mitochondrial and nuclear genes. These analyses show that the type species of Goniodoris, G. nodosa, is not a member of the clade constituted by the focal species of our study; the valid name for this clade is Pelagella. Six new species of Pelagella, P. albopunctata n. sp., P. balanoyensis n. sp., P. longicornis n. sp., P. scottjohnsoni n. sp., P. rubrobranchiata n. sp. and P. vitrea n. sp., are described.
{"title":"When a genus must become two: resurrection of Pelagella Gray, 1850 with the description of six new species","authors":"Sofía Paz-Sedano, D. Smirnoff, T. Gosliner, M. Pola","doi":"10.1093/mollus/eyad008","DOIUrl":"https://doi.org/10.1093/mollus/eyad008","url":null,"abstract":"\u0000 Goniodoris is the third most diverse genus of the nudibranch family Goniodorididae. The genus has undergone several taxonomic changes, with c. one-third of the recognized species of Goniodoris having been synonymized (most of these are junior synonyms of genera from other families). In addition, Goniodoris includes other synonymized genera within it, such as Pelagella, which was erected for Doris pareti. This species was synonymized with Goniodoris castanea and the genus Pelagella went almost unnoticed. In the present study, we investigate the systematics of the genus Goniodoris by examining specimens of G. castanea from England and Spain, G. joubini from Hawaii and six undescribed Goniodoris species from Australia, the Philippines and Mozambique. The morphology of the new species is studied using dissections of the internal organs and scanning electron micrographs of the radulae, labial cuticles and the penis. We also carried out phylogenetic analyses using partial DNA sequences of mitochondrial and nuclear genes. These analyses show that the type species of Goniodoris, G. nodosa, is not a member of the clade constituted by the focal species of our study; the valid name for this clade is Pelagella. Six new species of Pelagella, P. albopunctata n. sp., P. balanoyensis n. sp., P. longicornis n. sp., P. scottjohnsoni n. sp., P. rubrobranchiata n. sp. and P. vitrea n. sp., are described.","PeriodicalId":50126,"journal":{"name":"Journal of Molluscan Studies","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2023-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49382340","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}
Reproductive data on marine molluscs are imperative for informing conservation and management strategies. Most methods for assessing reproductive periodicity are lethal, which could be unfavourable for fragile populations. This study aimed to trial a nonlethal, drill-biopsy technique for assessing the reproductive cycle in the turbinid gastropod, Turbo militaris. This technique was tested in the laboratory, where a small hole was drilled into the shell, from where a biopsy of the gonad was taken. The procedures resulted in zero mortalities and rapid recovery of the animals when returned to seawater. Sex was identified by viewing the gonad colour through the shell hole and confirmed by viewing gametes from a biopsy. Preservation of the female biopsy was investigated, with buffered formalin found to be the most suitable solution. The drill-biopsy method was also tested in the field; five (out of six) recaptured T. militaris had repaired the shell hole after 6 weeks, and two were recaptured on multiple occasions up to the end of this study, 10 months later. The size–frequency distributions of oocytes from female biopsies suggested an increase in mode size over 2 months with a shift towards a higher number of larger oocytes, supporting the practicality of this nonlethal approach to evaluate reproductive periodicity and sex determination. Nonlethal sampling is recommended for broad-scale studies and populations under stress; methods, such as the drill-biopsy technique, facilitate reproductive sampling without detriment to the target populations.
{"title":"Shell drilling and gonad biopsies provide a rapid, nonlethal method for in situ assessment of reproductive periodicity in a turbinid gastropod","authors":"Kate Seinor, K. Benkendorff","doi":"10.1093/mollus/eyad012","DOIUrl":"https://doi.org/10.1093/mollus/eyad012","url":null,"abstract":"\u0000 Reproductive data on marine molluscs are imperative for informing conservation and management strategies. Most methods for assessing reproductive periodicity are lethal, which could be unfavourable for fragile populations. This study aimed to trial a nonlethal, drill-biopsy technique for assessing the reproductive cycle in the turbinid gastropod, Turbo militaris. This technique was tested in the laboratory, where a small hole was drilled into the shell, from where a biopsy of the gonad was taken. The procedures resulted in zero mortalities and rapid recovery of the animals when returned to seawater. Sex was identified by viewing the gonad colour through the shell hole and confirmed by viewing gametes from a biopsy. Preservation of the female biopsy was investigated, with buffered formalin found to be the most suitable solution. The drill-biopsy method was also tested in the field; five (out of six) recaptured T. militaris had repaired the shell hole after 6 weeks, and two were recaptured on multiple occasions up to the end of this study, 10 months later. The size–frequency distributions of oocytes from female biopsies suggested an increase in mode size over 2 months with a shift towards a higher number of larger oocytes, supporting the practicality of this nonlethal approach to evaluate reproductive periodicity and sex determination. Nonlethal sampling is recommended for broad-scale studies and populations under stress; methods, such as the drill-biopsy technique, facilitate reproductive sampling without detriment to the target populations.","PeriodicalId":50126,"journal":{"name":"Journal of Molluscan Studies","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2023-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42264999","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}
Nathaniel Soon, Z. B. R. Quek, Sebastian Pohl, Benjamin J. Wainwright
The advent of molecular systematics has revolutionized our knowledge of biodiversity, revealing undiscovered cryptic lineages across the tree of life. Correspondingly, an increasing number of nudibranch species complexes have been found and described through integrative taxonomic approaches. Pteraeolidia ‘semperi’ (Nudibranchia: Cladobranchia: Aeolidioidea) presently represents a species complex, possessing ambiguous systematics and an underestimated diversity. Sequencing and phylogenetic reconstructions based on the cytochrome c oxidase subunit I marker from 48 samples of P. ‘semperi’ collected from Singapore's southern waters, as well as morphological analyses including scanning electron microscopy of the radula, suggest that P. ‘semperi’ comprises several distinct cryptic lineages. We further characterized the Symbiodiniaceae communities of P. ‘semperi’ from Singapore using metabarcoding of the internal transcribed spacer 2 gene. Pteraeolidia ‘semperi’ from Singapore was found to predominantly host Cladocopium and Durusdinium symbionts, and was significantly structured by biogeography. This study elucidates the present taxonomic diversity of P. ‘semperi’ in Singapore and contributes to the growing body of work on the diversity of algal symbionts associated with this enigmatic taxon.
{"title":"More than meets the eye: characterizing the cryptic species complex and Symbiodiniaceae communities in the reef-dwelling nudibranch Pteraeolidia ‘semperi’ (Nudibranchia: Aeolidioidea) from Singapore","authors":"Nathaniel Soon, Z. B. R. Quek, Sebastian Pohl, Benjamin J. Wainwright","doi":"10.1093/mollus/eyad011","DOIUrl":"https://doi.org/10.1093/mollus/eyad011","url":null,"abstract":"\u0000 The advent of molecular systematics has revolutionized our knowledge of biodiversity, revealing undiscovered cryptic lineages across the tree of life. Correspondingly, an increasing number of nudibranch species complexes have been found and described through integrative taxonomic approaches. Pteraeolidia ‘semperi’ (Nudibranchia: Cladobranchia: Aeolidioidea) presently represents a species complex, possessing ambiguous systematics and an underestimated diversity. Sequencing and phylogenetic reconstructions based on the cytochrome c oxidase subunit I marker from 48 samples of P. ‘semperi’ collected from Singapore's southern waters, as well as morphological analyses including scanning electron microscopy of the radula, suggest that P. ‘semperi’ comprises several distinct cryptic lineages. We further characterized the Symbiodiniaceae communities of P. ‘semperi’ from Singapore using metabarcoding of the internal transcribed spacer 2 gene. Pteraeolidia ‘semperi’ from Singapore was found to predominantly host Cladocopium and Durusdinium symbionts, and was significantly structured by biogeography. This study elucidates the present taxonomic diversity of P. ‘semperi’ in Singapore and contributes to the growing body of work on the diversity of algal symbionts associated with this enigmatic taxon.","PeriodicalId":50126,"journal":{"name":"Journal of Molluscan Studies","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2023-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44747297","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}
Ecoimmunological research on molluscs and other invertebrates frequently quantifies phenoloxidase (PO) activity to estimate the strength of the immune function. PO enzymes form different families whose relative roles in oxidative reactions are typically unknown. Understanding this could allow enzyme-specific assays with higher accuracy than in commonly used nonspecific assays. We tested the contribution of different PO enzyme families to haemolymph PO-like activity in Lymnaea stagnalis snails using substrates specific to enzymes detected in L. stagnalis transcriptome data (p-phenylenediamine, specific to laccases; L-tyrosine, specific to tyrosinases) and compared the reactions to those with a nonspecific substrate (L-dopa). We found laccase-like but no tyrosinase-like activity. However, reactions with L-dopa were the strongest, possibly due to other oxidative enzymes in snail haemolymph. Laccase-like activity is common in molluscs, and we propose the use of enzyme-specific assays in future ecoimmunological studies of this taxon. The lack of tyrosinase-like activity in L. stagnalis contradicts earlier transcriptome data, which calls for investigating the expression of PO enzymes in L. stagnalis at the proteome level.
{"title":"Substrate specificity of phenoloxidase-like activity in an ecoimmunological model species Lymnaea stagnalis","authors":"O. Seppälä, Tamara Schlegel","doi":"10.1093/mollus/eyad005","DOIUrl":"https://doi.org/10.1093/mollus/eyad005","url":null,"abstract":"\u0000 Ecoimmunological research on molluscs and other invertebrates frequently quantifies phenoloxidase (PO) activity to estimate the strength of the immune function. PO enzymes form different families whose relative roles in oxidative reactions are typically unknown. Understanding this could allow enzyme-specific assays with higher accuracy than in commonly used nonspecific assays. We tested the contribution of different PO enzyme families to haemolymph PO-like activity in Lymnaea stagnalis snails using substrates specific to enzymes detected in L. stagnalis transcriptome data (p-phenylenediamine, specific to laccases; L-tyrosine, specific to tyrosinases) and compared the reactions to those with a nonspecific substrate (L-dopa). We found laccase-like but no tyrosinase-like activity. However, reactions with L-dopa were the strongest, possibly due to other oxidative enzymes in snail haemolymph. Laccase-like activity is common in molluscs, and we propose the use of enzyme-specific assays in future ecoimmunological studies of this taxon. The lack of tyrosinase-like activity in L. stagnalis contradicts earlier transcriptome data, which calls for investigating the expression of PO enzymes in L. stagnalis at the proteome level.","PeriodicalId":50126,"journal":{"name":"Journal of Molluscan Studies","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2023-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41603405","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 gastropod radula is highly diverse in structure in comparison with that of other mollusсs. The main radular types in the different phylogenetic groups of gastropods differ not only in the general morphology and configuration of the teeth but also in the mode of tooth synthesis and the ultrastructure of the formation zone. Previously, the formation and anlage of the radula in the ontogeny of radulae of all major phylogenetic gastropods groups have been studied, with the exception of the taenioglossan radula of Caenogastropoda. The data obtained in this study on the radular anlage and synthesis in one littorinimorph species Lacuna pallidula supplement the existing knowledge of diversity in gastropod radula formation. The radula is initially formed at the stage of the post-torsion veliger, with five teeth in each transverse row, and acquires the adult morphology before hatching from the egg mass. The larval radula is synthesized by a few morphologically uniform cells in the radular sac. Synthesis of the adult radula also occurs at the blind end of the radular sac, where groups of numerous odontoblasts each form one tooth, and membranoblasts, located on the ventral side, form the membrane. Characteristic features of the adult radular sac are an additional supporting cartilage-like structure at the radula curve in the middle of the radular sac, a well-defined proliferation zone in the zone of radula formation and the presence of an additional extracellular matrix around the teeth in the maturation zone.
{"title":"Development of Lacuna pallidula (da Costa, 1778) from the White Sea (Caenogastropoda: Littorinimorpha) with emphasis on radula formation","authors":"E. Vortsepneva, D. Herbert, Y. Kantor","doi":"10.1093/mollus/eyad004","DOIUrl":"https://doi.org/10.1093/mollus/eyad004","url":null,"abstract":"\u0000 The gastropod radula is highly diverse in structure in comparison with that of other mollusсs. The main radular types in the different phylogenetic groups of gastropods differ not only in the general morphology and configuration of the teeth but also in the mode of tooth synthesis and the ultrastructure of the formation zone. Previously, the formation and anlage of the radula in the ontogeny of radulae of all major phylogenetic gastropods groups have been studied, with the exception of the taenioglossan radula of Caenogastropoda. The data obtained in this study on the radular anlage and synthesis in one littorinimorph species Lacuna pallidula supplement the existing knowledge of diversity in gastropod radula formation. The radula is initially formed at the stage of the post-torsion veliger, with five teeth in each transverse row, and acquires the adult morphology before hatching from the egg mass. The larval radula is synthesized by a few morphologically uniform cells in the radular sac. Synthesis of the adult radula also occurs at the blind end of the radular sac, where groups of numerous odontoblasts each form one tooth, and membranoblasts, located on the ventral side, form the membrane. Characteristic features of the adult radular sac are an additional supporting cartilage-like structure at the radula curve in the middle of the radular sac, a well-defined proliferation zone in the zone of radula formation and the presence of an additional extracellular matrix around the teeth in the maturation zone.","PeriodicalId":50126,"journal":{"name":"Journal of Molluscan Studies","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2023-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44148772","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：