Malacologia最新文献

{"title":"Use of Native and Nonnative Fish Hosts by the Freshwater Mussel Anodonta californiensis (California Floater) in the Columbia River Basin","authors":"A. Maine, C. O'brien","doi":"10.4002/040.064.0204","DOIUrl":"https://doi.org/10.4002/040.064.0204","url":null,"abstract":"ABSTRACT Populations of many native freshwater mussels such as the California floater, Anodonta californiensis, are declining in the Columbia River Basin in the western United States. There are many possible reasons for this decline, including increased presence of nonnative fishes, especially piscivores that displace and reduce the abundance of native fishes. These nonnative fishes can negatively influence the early life history of A. californiensis, because this mussel uses native fishes to complete its life cycle. While Anodonta spp. can use nonnative fishes as hosts with limited success, the extent of this for A. californiensis is not well understood. We determined if the glochidia (larvae) of A. californiensis can successfully metamorphose using certain nonnative fishes, and we quantified differences in host effectiveness (number of juveniles produced) between native and nonnative fishes based on available fin area for attachment. Overall, native fishes hosted an average of 107.4 ± 39.9 (mean ± SE) juvenile mussels per fish while nonnative fishes hosted an average of 5.5 ± 4.9 juveniles per fish. This conclusion was unchanged when standardized for fish attachment area. Encystment of glochidia on native fishes yielded an average of 1.0 ± 0.1 juveniles/mm2 of attachable surface (total area of fins) area while nonnative fishes yielded an average of 0.16 ± 0.1 juveniles/mm2. The nonnative channel catfish, Ictalurus punctatus, did not yield any juvenile mussels and was identified as a nonhost species for A. californiensis. All other nonnative fishes tested were determined to be poor or marginal hosts. All native fishes were determined to be primary or secondary hosts for A. californiensis. The native fishes that yielded the highest number of juvenile mussels were sculpins, Cottus spp., and the redside shiner, Richardsonius balteatus, with an average of 196 and 151 juveniles per individual of each species, respectively. Our findings show that nonnative fishes are poor hosts for A. californiensis. However, nonnative fishes may contribute to the decline of native mussels in the Columbia River Basin by directly preying on and reducing the abundance of native host fishes and mussels. Future conservation plans for A. californiensis should consider the potential negative influence of nonnative fishes.","PeriodicalId":49895,"journal":{"name":"Malacologia","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2022-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47218181","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":"Review of the Genus Habeas from Brazil, with Description of Four New Species and in Which Anatomical Features Revealed That They Belong to Urocoptidae (Eupulmonata, Stylommatophora)","authors":"L. Simone","doi":"10.4002/040.064.0209","DOIUrl":"https://doi.org/10.4002/040.064.0209","url":null,"abstract":"ABSTRACT South American land snails are relatively poorly known, but their taxonomic relationships can be illuminated with the help of detailed anatomical descriptions and comparisons. The genus Habeas Simone, 2013, species of which are associated with caves, was tentatively described in the prosobranch family Diplommatinidae. Recently collected samples that permitted anatomical investigation, revealed that Habeas actually belongs to the eupulmonate family Urocoptidae. The genus is thus reviewed, including the three so far known species: H. corpus, H. data and H. priscus, all Simone, 2013. Four new species collected in Brazil are described: Habeas lekolus (from Cônego Marinho, Minas Gerais), H. peruassus (from Januária, Minas Gerais), H. lapensis (from Bom Jesus da Lapa, Bahia) and H. claudus (from Cocos, Bahia). Anatomical description is based on H. lekolus, revealing in its most interesting features, the absence of the ureter, presence of a pallial gland, lack of anterior duct to digestive gland, small penis and epiphallus, and absence of bursa copulatrix. Species in this genus usually inhabit cave habitats and are only found in Bahia (BA) and Minas Gerais (MG) Brazilian states, in areas close to São Francisco River. A brief discussion of the family attribution to Habeas is also performed. The present seven species in a genus recently discovered in a relatively small area demonstrate how weak the knowledge on the Brazilian malacofauna is.","PeriodicalId":49895,"journal":{"name":"Malacologia","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2022-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46566975","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":"Integrated Taxonomic Approach for Identification of Octopus Species from the Southwest Coast of India","authors":"Sneha Vargheese, K. K. Sajikumar, V. S. Basheer","doi":"10.4002/040.064.0210","DOIUrl":"https://doi.org/10.4002/040.064.0210","url":null,"abstract":"ABSTRACT Cephalopods are a commercially important resource for the Indian coast. Species of Octopus alone account for around 10% of the global cephalopod fishery and roughly 3% of Indian fisheries. Proper identification of cephalopods in the field is difficult, and accurate identification of species is important for conservation as well as for sustainable fisheries management of octopus species. With a view to identify and genetically catalogue the octopus species from the southwest Indian coast, 28 specimens were collected from different landing centres in the region and identified morphologically. Molecular characterization was done with partial sequence information from the mitochondrial Cytochrome C Oxidase-I (COI) gene. All the specimens analysed in the study belong to the family Octopodidae. The specimens were identified as four species of Amphioctopus: Amphioctopus neglectus, A. marginatus, A. aegina and A. rex, and two Cistopus: Cistopus indicus and C. taiwanicus, as well as, Octopus vulgaris and Callistoctopus macropus. In the present study, Octopus vulgaris showed genetic similarity with Octopus vulgaris Type III but with 1% divergence from Octopus vulgaris Type II and 3% divergence from Octopus vulgaris Type IV.","PeriodicalId":49895,"journal":{"name":"Malacologia","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2022-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45382491","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":"On the Need for Antibiotics to Reduce Subject Losses and Biases in Experiments with Aquatic Molluscs","authors":"T. DeWitt, H. L. Prestridge","doi":"10.4002/040.064.0211","DOIUrl":"https://doi.org/10.4002/040.064.0211","url":null,"abstract":"Biological research is frequently hampered, prevented, or biased by subject losses (Grafen, 1988; Weis, 2018). Subject losses force researchers to either repeat experiments or conduct analyses on a subset (the survivors) of the original experimental organisms. Repeating experiments has obvious financial and logistic consequences and offers no guarantee that losses will be fewer in subsequent efforts. Furthermore, data taken only on survivors is biased when mortality is correlated with variables of interest – the “missing fraction” problem (Grafen, 1988; Bennington & McGraw, 1995; Nakagawa & Freckleton, 2008). Subject losses reduce experimental sample size and balance and thereby also reduce statistical confidence, inferential power, and ultimately, the value of the research. Losses in aquatic research can stem from a wide range of causes such as inappropriate water chemistry, temperature, sudden change in physical parameters, or pathogens (Mori & Smith, 2019). Pathogens, in particular, can be a major cause of experimental subject mortality, even mass die-offs, due largely to the enclosed systems in which experiments are conducted (Kent et al., 2009; Mori et al., 2019). Yet even where pathogens cause little mortality, morbidity effects can similarly, though more cryptically, bias results (Kent et al. 2009). The best approach to protecting experiments where losses have been known to occur will often be to proactively prevent subject deaths and morbidity. Improved husbandry, including quarantines and preventive medication, can potentially reduce or eliminate subject losses and pathogen associated biases (McEwen & Fedorka-Cray, 2002). Preventive measures can introduce side-effects or bias of their own, such as gut or skin flora disruption which can impact experimental endpoints such as body weight (Carlson et al., 2017). Thus antibiotics should be considered only if benefits are likely to outweigh drawbacks for projects that are costly MALACOLOGIA, 2022, 64(2): 303–307","PeriodicalId":49895,"journal":{"name":"Malacologia","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2022-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46835886","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":"Reproduction and Recruitment of the Intertidal Clam Darina solenoides (Bivalvia: Mactridae) in Patagonian Sandy Shores, Argentina","authors":"M. López, Damián G. Gil, M. Kroeck, E. Morsan","doi":"10.4002/040.064.0203","DOIUrl":"https://doi.org/10.4002/040.064.0203","url":null,"abstract":"ABSTRACT Darina solenoides (P. P. King, 1832) is an abundant clam of sandy shores of southern South America. It has an essential ecologic role as a main food source for marine predators, including migratory seabirds, and is an intermediate host in parasitic life cycles. We describe the reproductive cycle and recruitment of D. solenoides in relation to environmental factors in central Patagonia, Argentina. Histological analysis of gonadal stages and quantitative indicators such as the condition index (CI), oocyte density and relative oocyte area (ROA) were examined monthly for two years (2016–2017; n = 1,315) from clams collected from two sandy shores of the San Jorge Gulf (SJG). Recruitment pattern was followed at a single site. The shell lengths ranged between 25.2 and 42.8 mm and the sex ratio did not differ significantly from 1:1. The proportion of clams showing total or partial castration by digenean trematodes was low (< 5%). A clear annual reproductive cycle was found and was characterized by high synchrony between sexes, years and sites. Proliferation of gonia extended throughout the colder months and vitellogenesis occurred mainly during the spring increase of seawater temperature and shortly after the major phytoplankton bloom. Maximum development of oocytes (mean diameter, 32.1 ± 12.9 µm) and presumed spawning by both males and females occurred during the austral summer. Settlement was also highest (mean = 162.8 ± 47.1 ind.m-2) during summer and was coincident with a second phytoplankton bloom that might favour larval development and subsequent early recruitment. This is the first reproductive study of a mactrid bivalve from the southwest Atlantic Ocean and provides useful information on the population dynamics of this key species from Patagonian sandy shores.","PeriodicalId":49895,"journal":{"name":"Malacologia","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2022-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43214891","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":"Redescription of Rhinus ciliatus (Gastropoda: Simpulopsidae), An Endemic Species from the Atlantic Rainforest in Brazil","authors":"Anna C. A. Salles, C. Oliveira","doi":"10.4002/040.064.0206","DOIUrl":"https://doi.org/10.4002/040.064.0206","url":null,"abstract":"ABSTRACT The genus Rhinus Martens, 1860, is represented in Brazil by about twenty species, which are predominantly found in the Atlantic rainforest, an endangered ecosystem with extraordinary biodiversity and high endemism. There is a dearth of detailed morphological data for most species of the genus Rhinus, and the anatomy of only a few species has been described. Rhinus ciliatus, an endemic species from southwestern Brazil, is known by few conchological traits and scarce anatomical data from the reproductive system and pallial cavity. In this study, we redescribe the shell morphology and soft body anatomy of Rhinus ciliatus in detail and compare the new data with known traits of other closely related species. Rhinus ciliatus is diagnosed by the following features: (i) transition from protoconch to teleoconch well marked; (ii) shell ovate-conic, accuminate; (iii) aperture sub-ovate, lip simple; (iv) kidney with granulated lamellae; and (v) marginal teeth with blunt spatula-shaped mesocones. The record of spermatophores for the genus is provided here for the first time.","PeriodicalId":49895,"journal":{"name":"Malacologia","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2022-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42427371","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":"Allometry in the Freshwater Pearl Mussel (Margaritifera margaritifera L.): Mussels Tend to Grow Flatter at Higher Water Speed","authors":"A. Cordero-Rivera, P. Ondina, A. Outeiro, R. Amaro, E. S. Miguel","doi":"10.4002/040.064.0208","DOIUrl":"https://doi.org/10.4002/040.064.0208","url":null,"abstract":"ABSTRACT The freshwater pearl mussel (Margaritifera margaritifera) is one of the longest-lived invertebrate species in the world and one of the most threatened freshwater animals in Europe. Its southernmost populations, located in northwestern Spain, are in a critical conservation situation and are still understudied. Here we calibrate a non-invasive method for calculating the volume of the shell and use it to study the ontogenetic scaling of shell volume on shell length. We characterized ontogenetic growth and determined allometric relationships in 16 M. margaritifera northwestern Spain populations by using ordinary least squares regression, major axis and reduced major axis methods. We estimated topographic slopes of the sampling points using a GIS system, as a proxy of water speed. We measured 803 shells and found that the volume of the shell can precisely be estimated using three linear measurements. We found evidence for negative allometry of shell volume in the global sample and in 11 populations. We hypothesized that water speed would affect allometric patterns of local populations. Results suggest a negative relationship between the allometric slope and the topographic slope of the river section inhabited by M. margaritifera. We propose that when water speed is higher, larger mussels become proportionally flatter than in locations where water current is slower, allowing them to burrow more easily in the sediment. Our method will allow estimation of M. margaritifera biomass and ontogenetic growth without killing any specimens, which will contribute to conservation programs for this species.","PeriodicalId":49895,"journal":{"name":"Malacologia","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2022-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42210122","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":"Morphological and Molecular Investigations on Squids of the Genera Uroteuthis and Loliolus from the Indian Coast to Resolve Taxonomic Ambiguities","authors":"N. Krishnan, S. Sukumaran, Wilson Sebastian, A. Gopalakrishnan","doi":"10.4002/040.064.0205","DOIUrl":"https://doi.org/10.4002/040.064.0205","url":null,"abstract":"ABSTRACT The phylogenetic relationships of inshore squid species in the family Loliginidae is still ambiguous owing to the lack of morphological and molecular data. In the present study, the taxonomic status of squid species Uroteuthis duvaucelii (Orbigny, 1848), Uroteuthis edulis (Hoyle, 1885), Uroteuthis singhalensis (Ortmann, 1891) and Loliolus hardwickei (Gray, 1849) from the Indian coast was elucidated by performing both morphological and genetic analyses. These Uroteuthis species showed marked differences in arm sucker teeth among species. Sharpness of tentacular sucker teeth was slightly increased in the order U. edulis < U. duvaucelii < U. singhalensis. Sexual dimorphism in tentacular teeth was observed in L. hardwickei. Uroteuthis singhalensis is morphologically very close to U. duvaucelii, as inferred by similar shape (broad, squared) and number (5–9) of arm teeth. Bayesian phylogenetic analysis using mitochondrial COI (650 bp), Cyt b (900bp) and COI-Cyt b combined gene sequences re-established the concept of monophyly of Loliolini with the additional number of species U. singhalensis and L. hardwickei. Our reconstructed phylogeny strongly supports Uroteuthis as a paraphyletic taxon as all organisms belonging to the genus Loliolus, including L. hardwickei (subgenus: Loliolus) explicitly grouped with one of the Uroteuthis clades. Distinct subclades within U. duvaucelii and U. edulis from the Indian Ocean may represent cryptic species.","PeriodicalId":49895,"journal":{"name":"Malacologia","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2022-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46159385","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":"A New Species of Placida (Gastropoda: Sacoglossa) from Southern South America","authors":"Nicolás Cetra, D. E. Gutiérrez Gregoric, Andrea Roche","doi":"10.4002/040.064.0106","DOIUrl":"https://doi.org/10.4002/040.064.0106","url":null,"abstract":"ABSTRACT Heterobranch sea slugs exhibit a wide range of body shapes, sizes and color patterns. The genus Placida (Sacoglossa) includes cryptic species, and in 2019 four species were recovered through molecular studies. Specimens of Placida collected in the Argentinian Sea (San Matias Gulf, Patagonia) between 2016 and 2019 are shown to belong to an undescribed species using molecular and morphological evidence. Placida sudamericana n. sp. is described using external, radular, penial stylet and egg mass characters. The specimens were always found associated with the green algae Codium fragile. Placida sudamericana is the only Placida species in the South Atlantic waters of South America and was recorded in a molluscan biodiversity hotspot.","PeriodicalId":49895,"journal":{"name":"Malacologia","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2021-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45268914","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":"Neuronal Transcriptome Analysis of a Widely Recognised Molluscan Model Organism Highlights the Absence of Key Proteins Involved in the De Novo Synthesis and Receptor-Mediation of Sex Steroids in Vertebrates","authors":"I. Fodor, J. Koene, Z. Pirger","doi":"10.4002/040.064.0103","DOIUrl":"https://doi.org/10.4002/040.064.0103","url":null,"abstract":"ABSTRACT Over the last ten years, the interpretation of the presence of vertebrate sex steroids in molluscs has changed dramatically. Evidence has been accumulating that CYP11A and CYP19A genes (encoding cholesterol side-chain cleavage enzyme and aromatase), that are crucial for the biosynthesis of sex steroids in vertebrates, as well as key functional sex steroid receptors, are missing in molluscan genomes. To provide further evidence, we sequenced the whole transcriptome of the central nervous system of the great pond snail (Lymnaea stagnalis) and screened it for sequences homologous to those used in the generally accepted vertebrate sex steroidogenesis pathway as well as the known sex steroid receptor-related genes (such as CYP11A, CYP19A, 3β-HSD, nPR, and nAR). Our screening confirmed the absence of several key sequences that are essential to accomplish a full sex steroid biosynthesis pathway similar to that of vertebrates. There was also no evidence for nuclear sex steroid receptors. Our findings support the contention that molluscan endocrinology differs from the well-characterized vertebrate endocrine system.","PeriodicalId":49895,"journal":{"name":"Malacologia","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2021-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46063712","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}