J. Büchner-Miranda, L. P. Salas-Yanquin, A. Averbuj, J. Navarro, V. Cubillos, A. Matos, S. Zabala, O. Chaparro
ABSTRACT Predatory strategies used by carnivorous gastropods may change during their ontogeny. In muricid gastropods attack mechanisms include an accessory boring organ (ABO), radula, labral tooth and/or pedal muscle. However, these mechanisms and their patterns of use in relation to the ontogeny of the carnivorous gastropod remain uncertain. We studied the occurrence of shifts in predatory strategies through the ontogeny of the gastropod Acanthina monodon preying on the mytilid Perumytilus purpuratus. Our results showed a direct relationship between predator and prey size. During attack, the small-sized snails (up to 18 mm shell length, SL) used exclusively the ABO, and medium-sized snails (18–20 mm SL) shifted to using the radula for rasping shells. Meanwhile, the largest-sized snails (> 20 mm SL) used the radula, but also occasionally the pedal muscle and labral tooth, to attack their prey. The site selectivity on the mytilid shell varied according to predatory mechanisms used. The small-sized gastropods used the ABO to drill the center of the prey valves, whereas mid-sized and large-sized snails used the radula and the labral tooth on the valve edges. Occasionally, large-sized snails also used ABO. Shifts in predatory strategies and attacked areas are influenced by the development and consolidation of structures involved in the attack as predator size increased. The incorporation of trace elements during rachidian teeth growth may enable major resistance to friction against carbonate prey valves, as well as the appearance and development of the labral tooth, play relevant roles in the predatory mechanism shifts, which allows the consumption of larger prey. These patterns described evidences the gastropod's predatory behaviour in terms of energetic gain while minimizing the risk of the predator itself being preyed on.
{"title":"Ontogenetic Shifts of Predatory Strategies by the Carnivorous Gastropod Acanthina monodon (Pallas, 1774)","authors":"J. Büchner-Miranda, L. P. Salas-Yanquin, A. Averbuj, J. Navarro, V. Cubillos, A. Matos, S. Zabala, O. Chaparro","doi":"10.4002/040.064.0105","DOIUrl":"https://doi.org/10.4002/040.064.0105","url":null,"abstract":"ABSTRACT Predatory strategies used by carnivorous gastropods may change during their ontogeny. In muricid gastropods attack mechanisms include an accessory boring organ (ABO), radula, labral tooth and/or pedal muscle. However, these mechanisms and their patterns of use in relation to the ontogeny of the carnivorous gastropod remain uncertain. We studied the occurrence of shifts in predatory strategies through the ontogeny of the gastropod Acanthina monodon preying on the mytilid Perumytilus purpuratus. Our results showed a direct relationship between predator and prey size. During attack, the small-sized snails (up to 18 mm shell length, SL) used exclusively the ABO, and medium-sized snails (18–20 mm SL) shifted to using the radula for rasping shells. Meanwhile, the largest-sized snails (> 20 mm SL) used the radula, but also occasionally the pedal muscle and labral tooth, to attack their prey. The site selectivity on the mytilid shell varied according to predatory mechanisms used. The small-sized gastropods used the ABO to drill the center of the prey valves, whereas mid-sized and large-sized snails used the radula and the labral tooth on the valve edges. Occasionally, large-sized snails also used ABO. Shifts in predatory strategies and attacked areas are influenced by the development and consolidation of structures involved in the attack as predator size increased. The incorporation of trace elements during rachidian teeth growth may enable major resistance to friction against carbonate prey valves, as well as the appearance and development of the labral tooth, play relevant roles in the predatory mechanism shifts, which allows the consumption of larger prey. These patterns described evidences the gastropod's predatory behaviour in terms of energetic gain while minimizing the risk of the predator itself being preyed on.","PeriodicalId":49895,"journal":{"name":"Malacologia","volume":"64 1","pages":"93 - 108"},"PeriodicalIF":1.3,"publicationDate":"2021-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42681647","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 Phenotypic characters of the uncommon Dimya cf. japonica, based on a specimen from Niue Is. in the South Pacific, are reported to represent the enigmatic Dimyidae in a wide-ranging Bivalvia phylogenetic scenario. The main conclusion is that dimyids are placed between ostreoideans and pectinoideans. This is supported by five synapomorphies. Dimyids are closer to pectinoideans, in that they share four synapomorphies.
{"title":"Phenotypic Features of Dimya cf. Japonica (Bivalvia, Dimyidae) from Niue Island (South Pacific) with Accounts on Its Phylogeny and Taxonomic Relationships","authors":"Luiz Ricardo L. Simone, V. S. do Amaral","doi":"10.4002/040.064.0107","DOIUrl":"https://doi.org/10.4002/040.064.0107","url":null,"abstract":"ABSTRACT Phenotypic characters of the uncommon Dimya cf. japonica, based on a specimen from Niue Is. in the South Pacific, are reported to represent the enigmatic Dimyidae in a wide-ranging Bivalvia phylogenetic scenario. The main conclusion is that dimyids are placed between ostreoideans and pectinoideans. This is supported by five synapomorphies. Dimyids are closer to pectinoideans, in that they share four synapomorphies.","PeriodicalId":49895,"journal":{"name":"Malacologia","volume":"64 1","pages":"121 - 136"},"PeriodicalIF":1.3,"publicationDate":"2021-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47730175","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 Continuing molecular and morphological investigations of a limpet recently reported as introduced to Sicily in the Mediterranean Sea have revealed it to be an undescribed species of Lottia Gray, 1833, a genus that is native to Sri Lanka and vicinity in the northern Indian Ocean. The genetic and morphological features of the limpets compared from Sicily and Sri Lanka correspond so closely that we do not hesitate to describe it collectively as Lottia iani n. sp., with type locality of Tangalle on the coast of Sri Lanka. Much is still unknown about its native range, when and how it arrived in Sicily, whether it is capable of impacting native species, and whether its introduction might be more widespread in the Mediterranean than just the particular eastern Sicilian localities where it has been observed. It is plausible that the introduction of L. iani to Sicily could have resulted from recent expansions to the Suez Canal, which is known to have led to other species introductions in recent years. Other possibilities include an introduction related to shipping or mariculture activities. However it managed to arrive, this limpet species has clearly been able to establish a self-recruiting local population at particular Sicilian localities with rocky volcanic shores.
对最近报道引进地中海西西里岛的一种帽贝进行的持续分子和形态学研究表明，它是1833年洛蒂亚·格雷(Lottia Gray)的一种未被描述的物种，该属原产于斯里兰卡及其北印度洋附近。来自西西里岛和斯里兰卡的帽贝的遗传和形态特征非常接近，以至于我们毫不犹豫地将其统称为Lottia iani n. sp，类型地点为斯里兰卡海岸的Tangalle。关于它的原生地，何时以及如何到达西西里岛，它是否有能力影响当地物种，以及它的引入是否可能在地中海比仅在西西里东部观察到的特定地区更广泛，仍有很多未知。有一种说法似乎是合理的，那就是由于最近苏伊士运河的扩张导致了西西里岛上L. iani的引入，众所周知，这导致了近年来其他物种的引入。其他可能性包括与航运或海水养殖活动有关的介绍。不管它是如何到达的，这种帽贝显然已经能够在西西里的岩石火山海岸上建立一个自我招募的地方种群。
{"title":"A Limpet (Lottiidae), Introduced to Sicily, is Traced to Its Homeland in Sri Lanka and Described as a New Species","authors":"D. Scuderi, T. Nakano, D. Eernisse","doi":"10.4002/040.064.0104","DOIUrl":"https://doi.org/10.4002/040.064.0104","url":null,"abstract":"ABSTRACT Continuing molecular and morphological investigations of a limpet recently reported as introduced to Sicily in the Mediterranean Sea have revealed it to be an undescribed species of Lottia Gray, 1833, a genus that is native to Sri Lanka and vicinity in the northern Indian Ocean. The genetic and morphological features of the limpets compared from Sicily and Sri Lanka correspond so closely that we do not hesitate to describe it collectively as Lottia iani n. sp., with type locality of Tangalle on the coast of Sri Lanka. Much is still unknown about its native range, when and how it arrived in Sicily, whether it is capable of impacting native species, and whether its introduction might be more widespread in the Mediterranean than just the particular eastern Sicilian localities where it has been observed. It is plausible that the introduction of L. iani to Sicily could have resulted from recent expansions to the Suez Canal, which is known to have led to other species introductions in recent years. Other possibilities include an introduction related to shipping or mariculture activities. However it managed to arrive, this limpet species has clearly been able to establish a self-recruiting local population at particular Sicilian localities with rocky volcanic shores.","PeriodicalId":49895,"journal":{"name":"Malacologia","volume":"64 1","pages":"79 - 92"},"PeriodicalIF":1.3,"publicationDate":"2021-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42705413","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}
Hanane Rassam, C. Albrecht, R. Sousa, M. Lopes‐Lima, H. Benaissa, M. Ghamizi
ABSTRACT The morphological plasticity of bivalve species may impair their correct identification. Pisidium species (Sphaeriidae) are difficult to distinguish, notably the common pea clam, Pisidium casertanum (Poli, 1791), which is a polymorphic species, often misidentified and confused with other Pisidium species. This is especially true since this species is the most euryecious of the genus, being able to colonize very different habitats. In this study, elliptic Fourier Analysis, a geometric morphometric method, was used to assess intraspecific variation in P. casertanum. Sampling of specimens was done in three habitat types – springs, lakes and streams – in the Mediterranean biodiversity hotspot region, using the Sebou basin in Morocco as a study area. In addition to the geometric morphometric method, linear measurements of the shell were used to assess growth patterns. Results revealed differences in the hinge plate, which is broader in shells collected from lakes, whereas it is higher in shells of springs. The geometric morphometric method clearly showed shape differences between individuals of the three habitats. Specimens of lakes were the most distinguishable, presenting more elongated shells than those from springs and streams, which are shorter but higher. Individuals from the three habitat types presented a negative allometric growth pattern whereby the shell of animals grows more slowly in height than in length. The use of linear and geometric morphometric methods led to conclude that the morphology of P. casertanum is, in fact, highly influenced by its environment, in particular, its habitat type.
{"title":"Intraspecific Variation in the Common Pea Clam, Pisidium casertanum (Poli, 1791) (Bivalvia: Sphaeriidae): A Geometric Morphometric Analysis","authors":"Hanane Rassam, C. Albrecht, R. Sousa, M. Lopes‐Lima, H. Benaissa, M. Ghamizi","doi":"10.4002/040.063.0203","DOIUrl":"https://doi.org/10.4002/040.063.0203","url":null,"abstract":"ABSTRACT The morphological plasticity of bivalve species may impair their correct identification. Pisidium species (Sphaeriidae) are difficult to distinguish, notably the common pea clam, Pisidium casertanum (Poli, 1791), which is a polymorphic species, often misidentified and confused with other Pisidium species. This is especially true since this species is the most euryecious of the genus, being able to colonize very different habitats. In this study, elliptic Fourier Analysis, a geometric morphometric method, was used to assess intraspecific variation in P. casertanum. Sampling of specimens was done in three habitat types – springs, lakes and streams – in the Mediterranean biodiversity hotspot region, using the Sebou basin in Morocco as a study area. In addition to the geometric morphometric method, linear measurements of the shell were used to assess growth patterns. Results revealed differences in the hinge plate, which is broader in shells collected from lakes, whereas it is higher in shells of springs. The geometric morphometric method clearly showed shape differences between individuals of the three habitats. Specimens of lakes were the most distinguishable, presenting more elongated shells than those from springs and streams, which are shorter but higher. Individuals from the three habitat types presented a negative allometric growth pattern whereby the shell of animals grows more slowly in height than in length. The use of linear and geometric morphometric methods led to conclude that the morphology of P. casertanum is, in fact, highly influenced by its environment, in particular, its habitat type.","PeriodicalId":49895,"journal":{"name":"Malacologia","volume":"63 1","pages":"183 - 194"},"PeriodicalIF":1.3,"publicationDate":"2021-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41371328","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 Many mollusks host symbiotic microbiota that are tightly involved in molluscan biological functions and ecological interactions. Here, we review the described symbioses between molluscan hosts and their bacterial partners. We focus on associations where the molluscan host is hypothesized to gain an evolutionary advantage because of the role of its symbiont. In addition, we focus only on those relationships that have been established experimentally or at least show strong evidence for symbioses. Along with providing a review of the known molluscan host/microbe mutualistic symbioses, we also outline common methodologies in the study of these relationships. Last, we point out areas of further exploration for molluscan microbiome studies.
{"title":"A Review of the Molluscan Microbiome: Ecology, Methodology and Future","authors":"B. Chalifour, Jingchun Li","doi":"10.4002/040.063.0208","DOIUrl":"https://doi.org/10.4002/040.063.0208","url":null,"abstract":"ABSTRACT Many mollusks host symbiotic microbiota that are tightly involved in molluscan biological functions and ecological interactions. Here, we review the described symbioses between molluscan hosts and their bacterial partners. We focus on associations where the molluscan host is hypothesized to gain an evolutionary advantage because of the role of its symbiont. In addition, we focus only on those relationships that have been established experimentally or at least show strong evidence for symbioses. Along with providing a review of the known molluscan host/microbe mutualistic symbioses, we also outline common methodologies in the study of these relationships. Last, we point out areas of further exploration for molluscan microbiome studies.","PeriodicalId":49895,"journal":{"name":"Malacologia","volume":"63 1","pages":"285 - 304"},"PeriodicalIF":1.3,"publicationDate":"2021-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43474737","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}
M. C. Pardo-Gandarillas, Mariana Díaz-Santana-Iturrios, Mark C. Fenwick, R. Villanueva, C. Ibáñez
ABSTRACT Cirrate octopods are considered to resemble the ancestor of all octopuses. Cirrates inhabit the deep ocean and are characterized by the presence of fins, a cartilaginous inner shell and a single row of suckers alternating with pairs of cirri thus comprising uniserial suckers and biserial cirri. The objective of this contribution is to improve the taxonomy of Opisthoteuthis bruuni from the southeastern Pacific Ocean and to suggest a new hypothesis of cirrate phylogeny. Given that the most complete molecular data set for cirrates available in public databases is comprised almost exclusively of 16S rRNA gene sequences, we compared the morphological and mitochondrial gene 16S rRNA data generated in this study from the genus Opisthoteuthis from the southeastern Pacific Ocean. Additionally, we sequenced Opisthoteuthis chathamensis, Opisthoteuthis mero and Luteuthis dentatus from the southwestern Pacific, as along with Cirroctopus mawsoni from Antarctic waters. The morphological data and the phylogenetic analysis confirm the status of Opisthoteuthis bruuni as a member of genus Opisthoteuthis and the family Opisthoteuthidae. This re-description includes the first morphological characterization of the male and female adult stage of O. bruuni, in addition to reporting geographic and bathymetric range extensions. Opisthoteuthis bruuni presents conspicuous morphological features (small terminal fins, short cirri and U-shaped shell). Our phylogenetic tree supports three families: Cirroctopodidae, Cirroteuthidae and Opisthoteuthidae, which is different from the phylogenetic arrangements previously reported.
{"title":"Redescription of the Flapjack Octopod, Opisthoteuthis bruuni (Cephalopoda: Opisthoteuthidae), from the Southeastern Pacific Ocean and Evolutionary Relationships of Cirrate Octopods","authors":"M. C. Pardo-Gandarillas, Mariana Díaz-Santana-Iturrios, Mark C. Fenwick, R. Villanueva, C. Ibáñez","doi":"10.4002/040.063.0201","DOIUrl":"https://doi.org/10.4002/040.063.0201","url":null,"abstract":"ABSTRACT Cirrate octopods are considered to resemble the ancestor of all octopuses. Cirrates inhabit the deep ocean and are characterized by the presence of fins, a cartilaginous inner shell and a single row of suckers alternating with pairs of cirri thus comprising uniserial suckers and biserial cirri. The objective of this contribution is to improve the taxonomy of Opisthoteuthis bruuni from the southeastern Pacific Ocean and to suggest a new hypothesis of cirrate phylogeny. Given that the most complete molecular data set for cirrates available in public databases is comprised almost exclusively of 16S rRNA gene sequences, we compared the morphological and mitochondrial gene 16S rRNA data generated in this study from the genus Opisthoteuthis from the southeastern Pacific Ocean. Additionally, we sequenced Opisthoteuthis chathamensis, Opisthoteuthis mero and Luteuthis dentatus from the southwestern Pacific, as along with Cirroctopus mawsoni from Antarctic waters. The morphological data and the phylogenetic analysis confirm the status of Opisthoteuthis bruuni as a member of genus Opisthoteuthis and the family Opisthoteuthidae. This re-description includes the first morphological characterization of the male and female adult stage of O. bruuni, in addition to reporting geographic and bathymetric range extensions. Opisthoteuthis bruuni presents conspicuous morphological features (small terminal fins, short cirri and U-shaped shell). Our phylogenetic tree supports three families: Cirroctopodidae, Cirroteuthidae and Opisthoteuthidae, which is different from the phylogenetic arrangements previously reported.","PeriodicalId":49895,"journal":{"name":"Malacologia","volume":"63 1","pages":"155 - 169"},"PeriodicalIF":1.3,"publicationDate":"2021-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48382585","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 Current knowledge on the pyramidellids from the southern tip of South America appears restricted to a couple of species described in the beginning of the 20th century and a few taxa subsequently reported from this area, including some species recognized as new, but never formally described. This study fills this gap in the knowledge by performing the first revision on the diversity of Pyramidellidae occurring in the Magellanic Province. The material for this study arises from extant collections made along the Atlantic and Pacific coasts of Patagonia, the Beagle Channel, the Magellan Strait and in Burdwood Bank; this information was supplied with specimens from museum collections. As part of this study, eight pyramidellid species, belonging to the genera Turbonilla, Fargoa, Menestho and Brachystomia are recognized from the Magellanic Province, including five species new to science: Turbonilla deseadensis n. sp., Menestho beaglensis n. sp., M. patagonica n. sp., Brachystomia conica n. sp. and B. tenuilirata n. sp. The distinctive characters of Menestho, a genus frequently misunderstood in the past, are also discussed. The presence of Menestho and Brachystomia are here documented for the first time for the southern tip of South America. In addition, a neotype for Turbonilla strebeli Strebel, 1905 (non Verrill, 1880) is here designated.
{"title":"Pyramidellidae (Gastropoda: Heterobranchia) from the End of the World","authors":"Javier Di Luca, Marina Güller, D. Zelaya","doi":"10.4002/040.063.0205","DOIUrl":"https://doi.org/10.4002/040.063.0205","url":null,"abstract":"ABSTRACT Current knowledge on the pyramidellids from the southern tip of South America appears restricted to a couple of species described in the beginning of the 20th century and a few taxa subsequently reported from this area, including some species recognized as new, but never formally described. This study fills this gap in the knowledge by performing the first revision on the diversity of Pyramidellidae occurring in the Magellanic Province. The material for this study arises from extant collections made along the Atlantic and Pacific coasts of Patagonia, the Beagle Channel, the Magellan Strait and in Burdwood Bank; this information was supplied with specimens from museum collections. As part of this study, eight pyramidellid species, belonging to the genera Turbonilla, Fargoa, Menestho and Brachystomia are recognized from the Magellanic Province, including five species new to science: Turbonilla deseadensis n. sp., Menestho beaglensis n. sp., M. patagonica n. sp., Brachystomia conica n. sp. and B. tenuilirata n. sp. The distinctive characters of Menestho, a genus frequently misunderstood in the past, are also discussed. The presence of Menestho and Brachystomia are here documented for the first time for the southern tip of South America. In addition, a neotype for Turbonilla strebeli Strebel, 1905 (non Verrill, 1880) is here designated.","PeriodicalId":49895,"journal":{"name":"Malacologia","volume":"63 1","pages":"225 - 242"},"PeriodicalIF":1.3,"publicationDate":"2021-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49425835","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 Pseudiberus Ancey, 1887, in Shandong, China, distributed in the mid to the south mountainous areas of the province, represents the largest terrestrial mollusks in this region. By molecular phylogenetic inference and genetic distance comparison based on ITS2 + 16S sequences, P. tectumsinense tectumsinense (Martens, 1873), P. tectumsinense zenonis (Gredler, 1882), P. tectumsinense anderssoni (Odhner, 1925) and P. tectumsinense depressus (Yen, 1935), are confirmed to be subspecies under P. tectumsinense (Martens, 1873). Pseudiberus tectumsinense pingi, new subspecies, is proposed to be new based on shell morphology, anatomy, and evidence of molecular phylogeny. Pseudiberus futtereri (Andreae, 1900) is removed from the species list of Shandongese Pseudiberus. The proximal accessory sac, observed in all the anatomically known Pseudiberus from Shandong, is described for the first time in dart sac apparatus from the bradybaenine snails. The variations and patterns of the proximal accessory sac among Pseudiberus tectumsinense subspecies and P. chentingensis distributed east to the Taihangshan Mountain Chain are examined. The close relationship among Shandong's Pseudiberus might be indicative of their rather recent evolutionary divergence, which was possibly driven by allopatric isolation of populations confined to refugial habitats like isolated mountain tops surrounded by extensive flood plains.
{"title":"Review of the Genus Pseudiberus Ancey, 1887 (Eupulmonata: Camaenidae) in Shandong Province, China","authors":"Guoyi Zhang, Min Wu, F. Köhler, Teng-Liang Liu","doi":"10.4002/040.063.0207","DOIUrl":"https://doi.org/10.4002/040.063.0207","url":null,"abstract":"ABSTRACT The genus Pseudiberus Ancey, 1887, in Shandong, China, distributed in the mid to the south mountainous areas of the province, represents the largest terrestrial mollusks in this region. By molecular phylogenetic inference and genetic distance comparison based on ITS2 + 16S sequences, P. tectumsinense tectumsinense (Martens, 1873), P. tectumsinense zenonis (Gredler, 1882), P. tectumsinense anderssoni (Odhner, 1925) and P. tectumsinense depressus (Yen, 1935), are confirmed to be subspecies under P. tectumsinense (Martens, 1873). Pseudiberus tectumsinense pingi, new subspecies, is proposed to be new based on shell morphology, anatomy, and evidence of molecular phylogeny. Pseudiberus futtereri (Andreae, 1900) is removed from the species list of Shandongese Pseudiberus. The proximal accessory sac, observed in all the anatomically known Pseudiberus from Shandong, is described for the first time in dart sac apparatus from the bradybaenine snails. The variations and patterns of the proximal accessory sac among Pseudiberus tectumsinense subspecies and P. chentingensis distributed east to the Taihangshan Mountain Chain are examined. The close relationship among Shandong's Pseudiberus might be indicative of their rather recent evolutionary divergence, which was possibly driven by allopatric isolation of populations confined to refugial habitats like isolated mountain tops surrounded by extensive flood plains.","PeriodicalId":49895,"journal":{"name":"Malacologia","volume":"63 1","pages":"257 - 284"},"PeriodicalIF":1.3,"publicationDate":"2021-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44529927","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. Rezende, Paula Spotorno-Oliveira, S. D’ávila, L. Maia, L. F. Cappa de Oliveira
ABSTRACT Using analytical (Raman spectroscopy) and imaging (scanning electron microscopy) approaches, we evidenced a biogenic mineralization process in the pedal mucus of the vermetids Eualetes tulipa and Petaloconchus varians. Raman spectra showed the presence of main bands around v1(CO) 1,085, n4(OCO) 717 and 705 cm-1 attributed to stretching modes of calcium carbonate crystallized as calcite and aragonite. SEM images showed the presence of aragonite needles and rhombohedral crystals of calcite in the mucus. Secondary nucleation from calcium carbonate precursors is the most probably pathway for the formation and growth of calcium carbonate crystals in feeding mucus of E. tulipa and P. varians. The tube-like shells of vermetids are very plastic. They are capable of continuously modify the direction of the shell aperture, remolding their tubes and building terminal structures. As a result, vermetid shells may act as exploratory tubes that allow the snail to profit from a better water flow, avoid obstacles and successfully compete for space. Such plasticity probably demands an extra supply of calcium carbonate, particularly when indeterminate growth is involved, as is the case for species of Eualetes and Petaloconchus; this would explain the functional significance of the biogenic calcium carbonate formation in the feeding mucus.
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