Abstract: In this paper, a new species in the genus Graphis Jeffreys, 1867 is described. Graphis peruviana sp. nov. from Chérrepe Beach (7°10′34″S, 79°41′25″W), Lambayeque, Peru, represents the first report of a member of the genus Graphis in the eastern South Pacific.
{"title":"First Report of the Genus Graphis (Gastropoda: Tofanellidae) in the Eastern South Pacific, with a Description of a New Species","authors":"L. E. C. Siadén, J. Céspedes, H. Kajihara","doi":"10.4003/006.035.0209","DOIUrl":"https://doi.org/10.4003/006.035.0209","url":null,"abstract":"Abstract: \u0000 In this paper, a new species in the genus Graphis Jeffreys, 1867 is described. Graphis peruviana sp. nov. from Chérrepe Beach (7°10′34″S, 79°41′25″W), Lambayeque, Peru, represents the first report of a member of the genus Graphis in the eastern South Pacific.","PeriodicalId":7779,"journal":{"name":"American Malacological Bulletin","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2017-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.4003/006.035.0209","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48778926","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}
Abstract: The invasive New Zealand mud snail, Potamopyrgus antipodarum (Gray 1843), has been present in the Laurentian Great Lakes for at least 20 years. Recently, the snail has spread to streams that empty into Lake Ontario. In the deep waters of Lake Ontario, detritus is the common food source for the snails; while in streams periphyton becomes an important part of their diet. This experiment was designed to test the hypothesis that a diet of periphyton will lead to a higher growth rate compared to detritus. Benthic sediment was collected from 18 m depth in Lake Erie. Periphyton was grown on small rocks collected from Spring Run stream in central Pennsylvania. Eighty juvenile snails (0.6–1.0 mm in length) were placed individually into plastic cups and divided into four treatments: control snails that were fed Spirulina powder (standard lab diet), snails kept in lake sediment, snails reared on rocks with periphyton growth, and snails in a combination habitat of rock and lake sediment. After six weeks, the snails were measured again. Snails in the periphyton-only treatment had a significantly greater growth rate than snails in the remaining treatments. The other three treatments resulted in similarly low growth rates. These results suggest that the change in diet from detritus-based to periphyton-based as the snails move from a lake to a stream environment may result in higher individual and possibly population growth rates, and thus could increase their invasion success.
{"title":"A Periphyton-Based Diet Results in an Increased Growth Rate Compared to a Detritus-Based Diet in the Invasive New Zealand Mud Snail (Potamopyrgus antipodarum).","authors":"E. P. Levri, S. Landis, Brittany J. Smith","doi":"10.4003/006.035.0109","DOIUrl":"https://doi.org/10.4003/006.035.0109","url":null,"abstract":"Abstract: The invasive New Zealand mud snail, Potamopyrgus antipodarum (Gray 1843), has been present in the Laurentian Great Lakes for at least 20 years. Recently, the snail has spread to streams that empty into Lake Ontario. In the deep waters of Lake Ontario, detritus is the common food source for the snails; while in streams periphyton becomes an important part of their diet. This experiment was designed to test the hypothesis that a diet of periphyton will lead to a higher growth rate compared to detritus. Benthic sediment was collected from 18 m depth in Lake Erie. Periphyton was grown on small rocks collected from Spring Run stream in central Pennsylvania. Eighty juvenile snails (0.6–1.0 mm in length) were placed individually into plastic cups and divided into four treatments: control snails that were fed Spirulina powder (standard lab diet), snails kept in lake sediment, snails reared on rocks with periphyton growth, and snails in a combination habitat of rock and lake sediment. After six weeks, the snails were measured again. Snails in the periphyton-only treatment had a significantly greater growth rate than snails in the remaining treatments. The other three treatments resulted in similarly low growth rates. These results suggest that the change in diet from detritus-based to periphyton-based as the snails move from a lake to a stream environment may result in higher individual and possibly population growth rates, and thus could increase their invasion success.","PeriodicalId":7779,"journal":{"name":"American Malacological Bulletin","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2017-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.4003/006.035.0109","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45717997","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}
70 If you search the NCBI nucleotide database for “Mollusca” and sort the entries by date modifi ed, the fi rst sequence to appear in the list is a 119 bp sequence from the 5.8S rRNA gene from the snail Helix pomatia Linnaeus, 1758, which was published by Fang and colleagues in 1982. Since then there has been, to put it lightly, signifi cant growth in the amount of available molecular sequence data from molluscs (3,371,221 sequences in the NCBI nucleotide database alone at the time of writing this manuscript). This growth has been punctuated by advances in DNA sequencing technology. I was born around the time that 5.8S sequence was uploaded and I’ve only ever seen discarded relics of the labor-intensive denaturing polyacrylamide-urea gel and autoradiography equipment that were used to generate it. When I began my Ph.D. dissertation research in 2007, my fi rst chapter was aimed at amplifying nuclear protein-coding genes via PCR from cDNA and sequencing them using Sanger sequencing on a capillary sequencer. We performed our own capillary sequencing and, although I imagine it was a breeze compared to running sequencing gels, every successful reaction felt like a personal victory. About a year after starting my dissertation research and before I was able to collect enough data using this approach to have anything remotely worthy of a publication, Roche 454 pyrosequencing came out and it became clear that it would be faster to start all over using this “cutting-edge” technology. In less than ten years, we have watched Roche 454 pyrosequencing rise and fall, Illumina sequencing soar in popularity and capability, and the cost of sequencing a human genome drop two orders of magnitude (Muir et al. 2016). Today, there are instruments that can generate about one billion sequences slightly longer than the aforementioned 5.8S rRNA sequence in 3 days for about USD $1,000 (Illumina 2016). Recent leaps forward in high-throughput DNA sequencing technology have made it feasible for single laboratories working on non-model organisms to conduct whole genome sequencing, sequence numerous transcriptomes, conduct targetcapture approaches to sequence pools of DNA enriched for genes of interest, etc. These exciting advances in highthroughput sequencing have led to a number of high profi le papers dealing with diverse aspects molluscan biology (e.g., Kocot et al. 2011, Smith et al. 2011, 2013, Zhang et al. 2012, Introduction to the AMS symposium “Phylogenomics of Mollusks,” 82 annual meeting of the American Malacological Society
{"title":"Introduction to the AMS Symposium “Phylogenomics of Mollusks,” 82nd Annual Meeting of the American Malacological Society","authors":"K. Kocot","doi":"10.4003/006.035.0110","DOIUrl":"https://doi.org/10.4003/006.035.0110","url":null,"abstract":"70 If you search the NCBI nucleotide database for “Mollusca” and sort the entries by date modifi ed, the fi rst sequence to appear in the list is a 119 bp sequence from the 5.8S rRNA gene from the snail Helix pomatia Linnaeus, 1758, which was published by Fang and colleagues in 1982. Since then there has been, to put it lightly, signifi cant growth in the amount of available molecular sequence data from molluscs (3,371,221 sequences in the NCBI nucleotide database alone at the time of writing this manuscript). This growth has been punctuated by advances in DNA sequencing technology. I was born around the time that 5.8S sequence was uploaded and I’ve only ever seen discarded relics of the labor-intensive denaturing polyacrylamide-urea gel and autoradiography equipment that were used to generate it. When I began my Ph.D. dissertation research in 2007, my fi rst chapter was aimed at amplifying nuclear protein-coding genes via PCR from cDNA and sequencing them using Sanger sequencing on a capillary sequencer. We performed our own capillary sequencing and, although I imagine it was a breeze compared to running sequencing gels, every successful reaction felt like a personal victory. About a year after starting my dissertation research and before I was able to collect enough data using this approach to have anything remotely worthy of a publication, Roche 454 pyrosequencing came out and it became clear that it would be faster to start all over using this “cutting-edge” technology. In less than ten years, we have watched Roche 454 pyrosequencing rise and fall, Illumina sequencing soar in popularity and capability, and the cost of sequencing a human genome drop two orders of magnitude (Muir et al. 2016). Today, there are instruments that can generate about one billion sequences slightly longer than the aforementioned 5.8S rRNA sequence in 3 days for about USD $1,000 (Illumina 2016). Recent leaps forward in high-throughput DNA sequencing technology have made it feasible for single laboratories working on non-model organisms to conduct whole genome sequencing, sequence numerous transcriptomes, conduct targetcapture approaches to sequence pools of DNA enriched for genes of interest, etc. These exciting advances in highthroughput sequencing have led to a number of high profi le papers dealing with diverse aspects molluscan biology (e.g., Kocot et al. 2011, Smith et al. 2011, 2013, Zhang et al. 2012, Introduction to the AMS symposium “Phylogenomics of Mollusks,” 82 annual meeting of the American Malacological Society","PeriodicalId":7779,"journal":{"name":"American Malacological Bulletin","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2017-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.4003/006.035.0110","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47998976","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}
Abstract: The genus Pyropelta McLean & Haszprunar, 1987 is exclusively restricted to deep-sea chemosynthesis-based environments, that range from the Western and Eastern Pacific to West Africa. In the present study, a new species, Pyropelta elongata sp. nov., collected from a methane seep area in South China Sea is described and illustrated. The generic assignation is mainly based on shell and radula characters. Pyropelta elongata sp. nov. is characterized by relatively large, elongate shell with a low profile and has a radula formula of (ca. 20)+5+1+5+(ca. 20). These features can distinguish the new species from other congeners.
{"title":"Description of Pyropelta elongata sp. nov. (Gastropoda, Pyropeltidae) from a Methane Seep Area in the South China Sea.","authors":"Shuqian Zhang, Suping Zhang","doi":"10.4003/006.035.0106","DOIUrl":"https://doi.org/10.4003/006.035.0106","url":null,"abstract":"Abstract: The genus Pyropelta McLean & Haszprunar, 1987 is exclusively restricted to deep-sea chemosynthesis-based environments, that range from the Western and Eastern Pacific to West Africa. In the present study, a new species, Pyropelta elongata sp. nov., collected from a methane seep area in South China Sea is described and illustrated. The generic assignation is mainly based on shell and radula characters. Pyropelta elongata sp. nov. is characterized by relatively large, elongate shell with a low profile and has a radula formula of (ca. 20)+5+1+5+(ca. 20). These features can distinguish the new species from other congeners.","PeriodicalId":7779,"journal":{"name":"American Malacological Bulletin","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2017-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.4003/006.035.0106","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47863643","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}
Abstract: Despite the existence of more than 565 islands in the upper three United States Great Lakes, land snails have been reported from only about 1% of them. This first publication about land snails of any island in eastern Lake Michigan reports on the 38 species (10,162 individuals) of land snails we found on South Fox Island. We examined leaf litter samples collected from 14 localities on South Fox Island in the years 1993 and 1997. We provide identification notes and habitat notes (beech-maple forest, cedar forest, meadow) for each of the species. The number of species, 38, on South Fox Island is about average when compared to the number of species from six other islands in the upper three Great Lakes that have had comparable sampling intensity. We report the northernmost published localities for two minute snails, Carychium nannodes G.H. Clapp, 1905 and Striatura meridionalis (Pilsbry and Ferriss, 1906), and one of the northernmost localities for the minute snail Guppya sterkii (Dall, 1888). The absence of two larger species that are present on the adjacent mainland is consistent with our hypothesis that the sequences of glacial history, island development, and northward snail colonization have influenced modern distributions of snails.
{"title":"Terrestrial Gastropods of South Fox Island, Leelanau Co., Michigan, U.S.A.","authors":"T. Pearce, Christen M. Drescher","doi":"10.4003/006.035.0105","DOIUrl":"https://doi.org/10.4003/006.035.0105","url":null,"abstract":"Abstract: Despite the existence of more than 565 islands in the upper three United States Great Lakes, land snails have been reported from only about 1% of them. This first publication about land snails of any island in eastern Lake Michigan reports on the 38 species (10,162 individuals) of land snails we found on South Fox Island. We examined leaf litter samples collected from 14 localities on South Fox Island in the years 1993 and 1997. We provide identification notes and habitat notes (beech-maple forest, cedar forest, meadow) for each of the species. The number of species, 38, on South Fox Island is about average when compared to the number of species from six other islands in the upper three Great Lakes that have had comparable sampling intensity. We report the northernmost published localities for two minute snails, Carychium nannodes G.H. Clapp, 1905 and Striatura meridionalis (Pilsbry and Ferriss, 1906), and one of the northernmost localities for the minute snail Guppya sterkii (Dall, 1888). The absence of two larger species that are present on the adjacent mainland is consistent with our hypothesis that the sequences of glacial history, island development, and northward snail colonization have influenced modern distributions of snails.","PeriodicalId":7779,"journal":{"name":"American Malacological Bulletin","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2017-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.4003/006.035.0105","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43139189","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}
Abstract: Cladobranchia is a diverse clade of nudibranch gastropods, with ∼1,000 coastal (benthic) and off shore (pelagic) marine species. Their diversity may be tied to dietary specialization and the evolution of remarkable adaptations that are rare among animals, such as the sequestration of cnidarian nematocysts. Due to the deep divergences within Cladobranchia, and other higher-order taxa within Mollusca, phylogenetic analyses based on morphology or a few genes have been unable to resolve relationships within these clades with high support. The introduction of high-throughput sequencing technologies, however, has provided the opportunity to collect large genomic data sets, which have proven useful in resolving relationships within molluscs, as in other metazoan groups. As sequencing costs decrease, it has become easier to collect ever larger data sets in an attempt to resolve relationships within more recently diverged groups, such as Cladobranchia. The phyly and relationships of the three main groups within Cladobranchia (Arminida, Dendronotida, and Aeolidida) have been difficult to determine, primarily due to the rapid evolution of mtDNA and rDNA genes analyzed in traditional molecular phylogenetic studies. In this review, I discuss the systematics of Cladobranchia in regards to morphological data, molecular analyses with one or a few genes, and address the impact of genomic data. I then contend that the supported phylogenetic hypotheses provided by high-throughput sequencing data will provide a better framework for studying taxonomy and character evolution within Cladobranchia, as these data provide strong support for Cladobranchia itself, as well as the nested subclades within it. Although it is important to note that a broader taxon sampling is still needed for genomic data, it is clear that utilizing these data has provided the most-well-supported phylogenetic hypotheses of Cladobranchia to date. In doing so, these genomic data have challenged well-established relationships, including the monophyly of Facelinidae and inclusion of Tritoniidae in Dendronotida, and resolved the position of taxa that have been traditionally quite difficult to place, including Melibe Rang, 1829 and the families Proctonotidae and Dironidae. Finally, these genomic data provide a much stronger phylogenetic framework for studying character evolution within Cladobranchia, including the evolution of nematocyst sequestration, one of the quintessential characters in this clade.
{"title":"Insights into the Systematics, Phylogeny, and Evolution of Cladobranchia (Gastropoda: Heterobranchia).","authors":"Jessica A. Goodheart","doi":"10.4003/006.035.0111","DOIUrl":"https://doi.org/10.4003/006.035.0111","url":null,"abstract":"Abstract: Cladobranchia is a diverse clade of nudibranch gastropods, with ∼1,000 coastal (benthic) and off shore (pelagic) marine species. Their diversity may be tied to dietary specialization and the evolution of remarkable adaptations that are rare among animals, such as the sequestration of cnidarian nematocysts. Due to the deep divergences within Cladobranchia, and other higher-order taxa within Mollusca, phylogenetic analyses based on morphology or a few genes have been unable to resolve relationships within these clades with high support. The introduction of high-throughput sequencing technologies, however, has provided the opportunity to collect large genomic data sets, which have proven useful in resolving relationships within molluscs, as in other metazoan groups. As sequencing costs decrease, it has become easier to collect ever larger data sets in an attempt to resolve relationships within more recently diverged groups, such as Cladobranchia. The phyly and relationships of the three main groups within Cladobranchia (Arminida, Dendronotida, and Aeolidida) have been difficult to determine, primarily due to the rapid evolution of mtDNA and rDNA genes analyzed in traditional molecular phylogenetic studies. In this review, I discuss the systematics of Cladobranchia in regards to morphological data, molecular analyses with one or a few genes, and address the impact of genomic data. I then contend that the supported phylogenetic hypotheses provided by high-throughput sequencing data will provide a better framework for studying taxonomy and character evolution within Cladobranchia, as these data provide strong support for Cladobranchia itself, as well as the nested subclades within it. Although it is important to note that a broader taxon sampling is still needed for genomic data, it is clear that utilizing these data has provided the most-well-supported phylogenetic hypotheses of Cladobranchia to date. In doing so, these genomic data have challenged well-established relationships, including the monophyly of Facelinidae and inclusion of Tritoniidae in Dendronotida, and resolved the position of taxa that have been traditionally quite difficult to place, including Melibe Rang, 1829 and the families Proctonotidae and Dironidae. Finally, these genomic data provide a much stronger phylogenetic framework for studying character evolution within Cladobranchia, including the evolution of nematocyst sequestration, one of the quintessential characters in this clade.","PeriodicalId":7779,"journal":{"name":"American Malacological Bulletin","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2017-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.4003/006.035.0111","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49175739","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}
B. Gołdyn, Ł. Kaczmarek, M. Roszkowska, Pedro Ríos Guayasamín, Z. Książkiewicz-Parulska, H. Cerda
Abstract: We are reporting the first locality of invasive giant African snail, Achatina (Lissachatina) fulica (Férussac, 1821) in the Ecuadorian Amazon. It was found present in 32 out of 50 urban sites studied. The abundance where present was relatively high when compared to literature from other parts of the world. The snails were found in aggregations, usually foraging — most often on dogs' feces. Statistical analysis suggests a preference toward this source of alimentation. This is the first report of such preference in this species, which is highly significant considering the possible implications. Besides the threat posed by an invasive species to the invaluable ecosystems of the Amazon, the pathogens transferred by A. fulica combined with a high abundance of the species in an urban environment and its food preferences may constitute an important health hazard for local human populations.
{"title":"Urban Ecology of Invasive Giant African Snail Achatina fulica (Férussac) (Gastropoda: Achatinidae) on its First Recorded Sites in the Ecuadorian Amazon","authors":"B. Gołdyn, Ł. Kaczmarek, M. Roszkowska, Pedro Ríos Guayasamín, Z. Książkiewicz-Parulska, H. Cerda","doi":"10.4003/006.035.0108","DOIUrl":"https://doi.org/10.4003/006.035.0108","url":null,"abstract":"Abstract: \u0000 We are reporting the first locality of invasive giant African snail, Achatina (Lissachatina) fulica (Férussac, 1821) in the Ecuadorian Amazon. It was found present in 32 out of 50 urban sites studied. The abundance where present was relatively high when compared to literature from other parts of the world. The snails were found in aggregations, usually foraging — most often on dogs' feces. Statistical analysis suggests a preference toward this source of alimentation. This is the first report of such preference in this species, which is highly significant considering the possible implications. Besides the threat posed by an invasive species to the invaluable ecosystems of the Amazon, the pathogens transferred by A. fulica combined with a high abundance of the species in an urban environment and its food preferences may constitute an important health hazard for local human populations.","PeriodicalId":7779,"journal":{"name":"American Malacological Bulletin","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2017-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.4003/006.035.0108","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44605746","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}
Maryori Ruiz-Velásquez, M. Zapata, M. T. González, Daniela Ordenes, Mauricio Escalona
Abstract: The mussel Choromytilus chorus (Molina, 1782) is a commercially and ecologically important bivalve, which is extensively distributed along the Chilean coast (20°S–54°S). However, there are no previous studies regarding the reproductive aspects of this species in the northern part of its range. Mussels were collected at Caleta Errázuriz, along the Antofagasta coast (ca. 24°S), between December 2014 and June 2015. A total of 1620 individuals were examined using histological techniques and macroscopic visual inspection. Seventeen size categories, which included individuals from 5 mm to 100 mm in length, were analyzed. The size at the onset of sexual differentiation and the size at first sexual maturity (50% mature individuals) were determined. Males comprised 49% of the total sample, and 51% were females. Mussels from 5–22 mm in valve length were undifferentiated and from 22–24 mm were sexually differentiated. The size at first sexual maturity was recorded as 38–40 mm. In vitro fertilization trials demonstrated that sexually differentiated individuals were able to produce viable gametes. The biological parameters analyzed for C. chorus were similar to those recorded for populations of this bivalve from the southern latitudes. However, the lower number of eggs per female and the smaller egg size suggests that the population parameters may be different for C. chorus between the northern and southern latitudes.
{"title":"Sexual Differentiation and size at First Maturity of the Mussel Choromytilus chorus (Molina, 1782) (Mollusca, Bivalvia) in Northern Chile.","authors":"Maryori Ruiz-Velásquez, M. Zapata, M. T. González, Daniela Ordenes, Mauricio Escalona","doi":"10.4003/006.035.0104","DOIUrl":"https://doi.org/10.4003/006.035.0104","url":null,"abstract":"Abstract: The mussel Choromytilus chorus (Molina, 1782) is a commercially and ecologically important bivalve, which is extensively distributed along the Chilean coast (20°S–54°S). However, there are no previous studies regarding the reproductive aspects of this species in the northern part of its range. Mussels were collected at Caleta Errázuriz, along the Antofagasta coast (ca. 24°S), between December 2014 and June 2015. A total of 1620 individuals were examined using histological techniques and macroscopic visual inspection. Seventeen size categories, which included individuals from 5 mm to 100 mm in length, were analyzed. The size at the onset of sexual differentiation and the size at first sexual maturity (50% mature individuals) were determined. Males comprised 49% of the total sample, and 51% were females. Mussels from 5–22 mm in valve length were undifferentiated and from 22–24 mm were sexually differentiated. The size at first sexual maturity was recorded as 38–40 mm. In vitro fertilization trials demonstrated that sexually differentiated individuals were able to produce viable gametes. The biological parameters analyzed for C. chorus were similar to those recorded for populations of this bivalve from the southern latitudes. However, the lower number of eggs per female and the smaller egg size suggests that the population parameters may be different for C. chorus between the northern and southern latitudes.","PeriodicalId":7779,"journal":{"name":"American Malacological Bulletin","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2017-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.4003/006.035.0104","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43467785","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}
W. Saunders, R. Mapes, M. White, L. Hastie, K. Yaqin
Abstract: The taxonomic history of Nautilus pompilius Linnaeus, 1758, the most widely distributed species of Nautilus Linnaeus, 1758, is complex, mostly owing to the antiquity of the earliest description by the naturalist Rumphius (Rumpf) in 1705. His account of its habits and illustrations of soft anatomy of specimens from Ambon, Molucca Islands, Indonesia were cited by Linnaeus in his description of N. pompilius. Nevertheless, there is almost no information on Nautilus in Indonesia. Live-caught animals (n = 44) from 150–400 m depth off Ambon provide the first morphologic and genetic details on Nautilus pompilius from the type region, including a recently proposed neotype for the type species. An additional sample (n = 62) obtained from the Sumbawa-Lombok Islands area, Indonesia, 1,500km to the southeast appears identical to those from Ambon. These populations have the largest known mature shells (mean ∼198mm diameter, ∼1,160 g shell plus body weight) of any of the numerous Indo-Pacific occurrences of Nautilus pompilius s.l. presently assigned to this species. Aside from size, few major phenotypic aspects differ from other populations of the species throughout its broad Indo-Pacific range. Data from two mitochondrial DNA gene regions identified a strongly supported clade comprising Ambon, Sumbawa, and Philippines N. pompilius s.s. These new data provide a baseline for evaluating genetic, phenotypic and geographic variation in the broadly distributed species N. pompilius s.l., as well as for establishing taxonomic relationships in populations of living Nautilus, including N. pompilius pompilius Linnaeus, 1758.
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