Abstract. Surveys of marine gastrotrichs on the coast of South Korea yielded a new species of the genus Tetranchyroderma, bearing 5-pronged hooks as a cuticular armature. Tetranchyroderma hummoni is characterized by a dorsal armature adorned with pentancres, whose central tines are about twice as long as peripheral tines. The new species is also characterized by bearing 3 large and broad papillae per side along boundary row of pentancres on oral hood, a pair of rod-like cephalic tentacles, and a pair of modified pestle organs. Moreover, this new species is clearly distinguished from its congeners by the number of dorsal, dorsolateral and ventrolateral cirratum-type tubes (6−10, 13−19, and 9−14 per side, respectively), and by a pair of foot-like ventral adhesive tubes. The description of the new species belonging to the genus Tetranchyroderma is based on detailed illustrations and scanning electron microscopy. We also provide a short account on the variability within the species, including the morphological difference between juveniles and adults.
{"title":"A new species of the genus Tetranchyroderma (Gastrotricha: Macrodasyida: Thaumastodermatidae) from Korea, with a peculiar pentancrous armature","authors":"Jimin Lee, C. Chang, Il-Hoi Kim","doi":"10.2988/17-00016","DOIUrl":"https://doi.org/10.2988/17-00016","url":null,"abstract":"Abstract. Surveys of marine gastrotrichs on the coast of South Korea yielded a new species of the genus Tetranchyroderma, bearing 5-pronged hooks as a cuticular armature. Tetranchyroderma hummoni is characterized by a dorsal armature adorned with pentancres, whose central tines are about twice as long as peripheral tines. The new species is also characterized by bearing 3 large and broad papillae per side along boundary row of pentancres on oral hood, a pair of rod-like cephalic tentacles, and a pair of modified pestle organs. Moreover, this new species is clearly distinguished from its congeners by the number of dorsal, dorsolateral and ventrolateral cirratum-type tubes (6−10, 13−19, and 9−14 per side, respectively), and by a pair of foot-like ventral adhesive tubes. The description of the new species belonging to the genus Tetranchyroderma is based on detailed illustrations and scanning electron microscopy. We also provide a short account on the variability within the species, including the morphological difference between juveniles and adults.","PeriodicalId":54578,"journal":{"name":"Proceedings of the Biological Society of Washington","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2017-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2988/17-00016","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43469697","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 spermatozoon of an undescribed species of Dolichodasys (Cephalodasyidae) from the Pacific coast of Panama was studied at structural and ultrastructural levels. Under optical microscopy, it appears as a short and wide cell with pointed extremities but without a flagellum. The cell body is made up of two well distinct regions: an anterior region with a homogeneous appearance, and a posterior region containing an evident rod-like nucleus. Under TEM, a peripheral layer of microtubules densely arranged extends for the whole cell length. In the anterior cell region, microtubules surround many tubular cisternae of smooth endoplasmic reticulum (SER), and a thin layer of vesicles with a probable acrosomal function lies just beneath the plasma membrane. The rod-shaped nucleus fills up the posterior cell region and forms a pouch that hosts a single large, irregular mitochondrial mass. A hypothesis about the motility of this aflagellate cell is advanced, on the basis of the coexistence of singlet microtubules and SER. The general architecture of Dolichodasys sp. spermatozoon departs from the Macrodasyida sperm basic model, consisting of a filiform cell with a corkscrew-shaped acrosome, a spring-shaped nucleus surrounding a mitochondrial axis and an ordinary flagellum. The unusual morphology of the Dolichodasys sperm seems to be unique in the family Cephalodasyidae: the data available for 6 species belonging to the other 4 genera of the family report spermatozoa perfectly matching the basic sperm plan of the Macrodasyida. A sister-taxon relationship between Dolichodasys and Cephalodasys, two genera drastically different in sperm shape, emerged from recent phylogenetic molecular studies, but it needs confirmation due to the still limited number of molecular data and the likely polyphyletic nature of the family Cephalodasyidae.
{"title":"The unusual spermatozoa of Dolichodasys sp. (Gastrotricha, Macrodasyida)","authors":"L. Guidi, M. Todaro, L. Cesaroni, M. Balsamo","doi":"10.2988/17-00009","DOIUrl":"https://doi.org/10.2988/17-00009","url":null,"abstract":"Abstract The spermatozoon of an undescribed species of Dolichodasys (Cephalodasyidae) from the Pacific coast of Panama was studied at structural and ultrastructural levels. Under optical microscopy, it appears as a short and wide cell with pointed extremities but without a flagellum. The cell body is made up of two well distinct regions: an anterior region with a homogeneous appearance, and a posterior region containing an evident rod-like nucleus. Under TEM, a peripheral layer of microtubules densely arranged extends for the whole cell length. In the anterior cell region, microtubules surround many tubular cisternae of smooth endoplasmic reticulum (SER), and a thin layer of vesicles with a probable acrosomal function lies just beneath the plasma membrane. The rod-shaped nucleus fills up the posterior cell region and forms a pouch that hosts a single large, irregular mitochondrial mass. A hypothesis about the motility of this aflagellate cell is advanced, on the basis of the coexistence of singlet microtubules and SER. The general architecture of Dolichodasys sp. spermatozoon departs from the Macrodasyida sperm basic model, consisting of a filiform cell with a corkscrew-shaped acrosome, a spring-shaped nucleus surrounding a mitochondrial axis and an ordinary flagellum. The unusual morphology of the Dolichodasys sperm seems to be unique in the family Cephalodasyidae: the data available for 6 species belonging to the other 4 genera of the family report spermatozoa perfectly matching the basic sperm plan of the Macrodasyida. A sister-taxon relationship between Dolichodasys and Cephalodasys, two genera drastically different in sperm shape, emerged from recent phylogenetic molecular studies, but it needs confirmation due to the still limited number of molecular data and the likely polyphyletic nature of the family Cephalodasyidae.","PeriodicalId":54578,"journal":{"name":"Proceedings of the Biological Society of Washington","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2017-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2988/17-00009","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48035633","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}
R. Hochberg, M. Todaro, Thiago Q. Araújo, Sarah Atherton, M. Balsamo, C. Chang, Maikon Di Dimenico, A. Garraffoni, L. Guidi, Tobias Känneby, A. Kieneke, J. J. Kirk, F. Leasi, Jimin Lee, T. Nesteruk, M. Dal Zotto, S. Bownes, L. Cesaroni, Il-Hoi Kim, L. Münter, R. Perissinotto
{"title":"A Tribute to William Hummon – Gastrotrich Biologist Extraordinaire","authors":"R. Hochberg, M. Todaro, Thiago Q. Araújo, Sarah Atherton, M. Balsamo, C. Chang, Maikon Di Dimenico, A. Garraffoni, L. Guidi, Tobias Känneby, A. Kieneke, J. J. Kirk, F. Leasi, Jimin Lee, T. Nesteruk, M. Dal Zotto, S. Bownes, L. Cesaroni, Il-Hoi Kim, L. Münter, R. Perissinotto","doi":"10.2988/17-00017","DOIUrl":"https://doi.org/10.2988/17-00017","url":null,"abstract":"","PeriodicalId":54578,"journal":{"name":"Proceedings of the Biological Society of Washington","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2017-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2988/17-00017","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47254082","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 A new species of Thaumastoderma (Gastrotricha: Macrodasyida: Thaumastodermatidae) is described from sublittoral sediments on the islands of Tobago (Trinidad and Tobago) and Carrie Bow Cay (Belize). Thaumastoderma ponticulus sp. nov. is similar to Th. ramuliferum and Th. cantacuzeni based on the presence of four pairs of dorsal cirrata tubes and a compound pair of spatulate tentacles. The main distinguishing characteristic is the presence of a fleshy bridge that interconnects the anterior and posterior spatulate tentacles on the head. Additional characters include the presence of two rows of anterior adhesive tubes, seven pairs of ventrolateral adhesive tubes, and five pairs of posterior adhesive tubes.
{"title":"Description of a new species of Thaumastoderma (Gastrotricha: Macrodasyida: Thaumastodermatidae) from Belize and Tobago","authors":"Thiago Q. Araújo, R. Hochberg","doi":"10.2988/17-00003","DOIUrl":"https://doi.org/10.2988/17-00003","url":null,"abstract":"Abstract A new species of Thaumastoderma (Gastrotricha: Macrodasyida: Thaumastodermatidae) is described from sublittoral sediments on the islands of Tobago (Trinidad and Tobago) and Carrie Bow Cay (Belize). Thaumastoderma ponticulus sp. nov. is similar to Th. ramuliferum and Th. cantacuzeni based on the presence of four pairs of dorsal cirrata tubes and a compound pair of spatulate tentacles. The main distinguishing characteristic is the presence of a fleshy bridge that interconnects the anterior and posterior spatulate tentacles on the head. Additional characters include the presence of two rows of anterior adhesive tubes, seven pairs of ventrolateral adhesive tubes, and five pairs of posterior adhesive tubes.","PeriodicalId":54578,"journal":{"name":"Proceedings of the Biological Society of Washington","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2017-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2988/17-00003","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47226564","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 Pseudostomella is comprosed of 17 species distributed in distinct coastal and shelf areas of the world. This taxon is characterized by a fleshy preoral apparatus, which is unique to the family and easily distinguishes species of Pseudostomella from species of the other 7 genera. The present study has two aims: 1) provide a phylogenetic reconstruction based on morphological characters using all valid species of the genus Pseudostomella; and 2) perform a Brooks Parsimony Analysis (BPA) based on new and published phylogenetic analyses to determine the biogeographical history of the thaumastodermatid lineage. The cladistic analysis conducted here supports the monophyly of Pseudostomella and the internal branchs are also supported by a relative high number of well-defined synapomorphies. Regarding historical biogeography, our results suggest that the thaumastodermatid diversification first occurred in epicontinental seas from the southern margin of Gondwana. These findings for thaumastodermatid gastrotrichs are similar to those of other historical biogeographical studies on marine invertebrates.
{"title":"Phylogeny of Pseudostomella Swedmark, 1956 (Gastrotricha: Macrodasyida) base on morphological data and first insights on the historical biogeography of Thaumastodermatidae","authors":"A. Garraffoni, Thiago Q. Araújo","doi":"10.2988/17-00014","DOIUrl":"https://doi.org/10.2988/17-00014","url":null,"abstract":"Abstract The genus Pseudostomella is comprosed of 17 species distributed in distinct coastal and shelf areas of the world. This taxon is characterized by a fleshy preoral apparatus, which is unique to the family and easily distinguishes species of Pseudostomella from species of the other 7 genera. The present study has two aims: 1) provide a phylogenetic reconstruction based on morphological characters using all valid species of the genus Pseudostomella; and 2) perform a Brooks Parsimony Analysis (BPA) based on new and published phylogenetic analyses to determine the biogeographical history of the thaumastodermatid lineage. The cladistic analysis conducted here supports the monophyly of Pseudostomella and the internal branchs are also supported by a relative high number of well-defined synapomorphies. Regarding historical biogeography, our results suggest that the thaumastodermatid diversification first occurred in epicontinental seas from the southern margin of Gondwana. These findings for thaumastodermatid gastrotrichs are similar to those of other historical biogeographical studies on marine invertebrates.","PeriodicalId":54578,"journal":{"name":"Proceedings of the Biological Society of Washington","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2017-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2988/17-00014","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47602598","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 Molecular surveys and studies of the muscle anatomy made evident that the mesopsammic gastrotrich Xenotrichula intermedia, previously regarded as a cosmopolitan species, comprises several distinct taxonomic units. These entities are to date referred to as cryptic species. Although other morphological traits seemed insufficient to differentiate geographically distant populations, investigations of the myomorphology displayed significant differences. Three muscular morphotypes of X. intermedia are known and distinguishable via properties of their dorsoventral and circular musculature. However, previous studies using confocal laser scanning microscopy (CLSM) conducted observations of the muscle architecture that aimed to apply older terminology of the only existing reconstruction that was based on fluorescence microscopy. Since detailed 3D reconstructions of the myoanatomy were never performed, comparisons between different morphotypes of X. intermedia stay a difficult endeavor. In this study, the muscular system of a North Sea population of X. intermedia is investigated and reconstructed using CLSM and 3D reconstruction software. Our aim is to test whether this population, adjacent to the type locality of X. intermedia, constitutes another muscular morphotype. The overall musculature of the North-Sea population is similar to that of the Mediterranean specimens. A Baltic Sea individual appears myoanatomically identical to these populations, too. This indicates a distinct morphotype with a pan-European distribution. Since the known muscular morphotypes are clearly distinguishable, we propose the presence of a species complex comprising a pan-European X. intermedia, a Persian X. aff. intermedia and a NW Atlantic X. aff. intermedia. Furthermore, our investigation demonstrates a much higher complexity of the longitudinal musculature than previously assumed, which leads us to reinterpret earlier myomorphological data, amend some terminology, and reconsider statements of homology that will provide a feasible foundation for future comparative studies.
{"title":"Novel myo-anatomical insights to the Xenotrichula intermedia species complex (Gastrotricha: Paucitubulatina): Implications for a pan-European species and reconsideration of muscle homology among Paucitubulatina","authors":"L. Münter, A. Kieneke","doi":"10.2988/17-00013","DOIUrl":"https://doi.org/10.2988/17-00013","url":null,"abstract":"Abstract Molecular surveys and studies of the muscle anatomy made evident that the mesopsammic gastrotrich Xenotrichula intermedia, previously regarded as a cosmopolitan species, comprises several distinct taxonomic units. These entities are to date referred to as cryptic species. Although other morphological traits seemed insufficient to differentiate geographically distant populations, investigations of the myomorphology displayed significant differences. Three muscular morphotypes of X. intermedia are known and distinguishable via properties of their dorsoventral and circular musculature. However, previous studies using confocal laser scanning microscopy (CLSM) conducted observations of the muscle architecture that aimed to apply older terminology of the only existing reconstruction that was based on fluorescence microscopy. Since detailed 3D reconstructions of the myoanatomy were never performed, comparisons between different morphotypes of X. intermedia stay a difficult endeavor. In this study, the muscular system of a North Sea population of X. intermedia is investigated and reconstructed using CLSM and 3D reconstruction software. Our aim is to test whether this population, adjacent to the type locality of X. intermedia, constitutes another muscular morphotype. The overall musculature of the North-Sea population is similar to that of the Mediterranean specimens. A Baltic Sea individual appears myoanatomically identical to these populations, too. This indicates a distinct morphotype with a pan-European distribution. Since the known muscular morphotypes are clearly distinguishable, we propose the presence of a species complex comprising a pan-European X. intermedia, a Persian X. aff. intermedia and a NW Atlantic X. aff. intermedia. Furthermore, our investigation demonstrates a much higher complexity of the longitudinal musculature than previously assumed, which leads us to reinterpret earlier myomorphological data, amend some terminology, and reconsider statements of homology that will provide a feasible foundation for future comparative studies.","PeriodicalId":54578,"journal":{"name":"Proceedings of the Biological Society of Washington","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2017-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2988/17-00013","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47560179","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 A new species of Redudasys (Macrodasyida: Redudasyidae) is described from Texas and Oregon, U.S.A. A single Texas specimen was reported (but not formally described and named) in 2014 from an artesian outflow in Spring Lake, San Marcos, Texas. The Texas specimen provided the first record of Redudasys from outside Brazil. Fifteen specimens were found and studied in 2015 and 2016 from sand pockets among boulders in the Little Nestucca River, near Pacific City, Oregon. Redudasys neotemperatus n. sp. is morphologically and genetically distinguishable from Redudasys fornerise Kisielewski, 1987a, the only formally described species in the genus up until now, and morphologically distinguishable from “Redudasys sp.”, an unnamed form reported by Garraffoni et al. in 2010 without genetic information. The Texas and Oregon specimens agree well morphologically and genetically.
{"title":"A new species of Redudasys (Gastrotricha: Macrodasyida: Redudasyidae) from the United States","authors":"Tobias Kånneby, J. J. Kirk","doi":"10.2988/17-00006","DOIUrl":"https://doi.org/10.2988/17-00006","url":null,"abstract":"Abstract A new species of Redudasys (Macrodasyida: Redudasyidae) is described from Texas and Oregon, U.S.A. A single Texas specimen was reported (but not formally described and named) in 2014 from an artesian outflow in Spring Lake, San Marcos, Texas. The Texas specimen provided the first record of Redudasys from outside Brazil. Fifteen specimens were found and studied in 2015 and 2016 from sand pockets among boulders in the Little Nestucca River, near Pacific City, Oregon. Redudasys neotemperatus n. sp. is morphologically and genetically distinguishable from Redudasys fornerise Kisielewski, 1987a, the only formally described species in the genus up until now, and morphologically distinguishable from “Redudasys sp.”, an unnamed form reported by Garraffoni et al. in 2010 without genetic information. The Texas and Oregon specimens agree well morphologically and genetically.","PeriodicalId":54578,"journal":{"name":"Proceedings of the Biological Society of Washington","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2017-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2988/17-00006","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41263023","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 generic name Polyborus has been traditionally associated with the “Crested Caracaras”, but confusion over its correct application has led to it recent falling out of use. Polyborus is based on a description by Marcgrave accompanied by a poor illustration, but only 2 species have ever been seriously considered as the identity of this description Long-winged Harrier Circus buffoni and Southern Caracara Caracara plancus. The nomenclatural history of this name is discussed and the identity of Marcgrave's description is elucidated as Yellow-headed Caracara Milvago chimachima. The implications for nomenclature are discussed, and it is recommended that both Polyborus and the name Falco brasiliensis (also based on the same description) be suppressed.
{"title":"On the correct application of the generic name Polyborus Vieillot, 1816 (Aves: Falconidae)","authors":"Paul A. Smith","doi":"10.2988/17-00008","DOIUrl":"https://doi.org/10.2988/17-00008","url":null,"abstract":"Abstract The generic name Polyborus has been traditionally associated with the “Crested Caracaras”, but confusion over its correct application has led to it recent falling out of use. Polyborus is based on a description by Marcgrave accompanied by a poor illustration, but only 2 species have ever been seriously considered as the identity of this description Long-winged Harrier Circus buffoni and Southern Caracara Caracara plancus. The nomenclatural history of this name is discussed and the identity of Marcgrave's description is elucidated as Yellow-headed Caracara Milvago chimachima. The implications for nomenclature are discussed, and it is recommended that both Polyborus and the name Falco brasiliensis (also based on the same description) be suppressed.","PeriodicalId":54578,"journal":{"name":"Proceedings of the Biological Society of Washington","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2017-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2988/17-00008","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45756286","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 Geographical patterns in microorganisms' distribution is a matter of intense debate. Following the assumption that “everything is everywhere” (EiE hypothesis), it is expected that microscopic animals do not have any scale spatial pattern of distribution due to high abundances, resting stages, and long-distance dispersal. Gastrotrichs are one of the most common components of the marine soft-body meiofauna. To assess the validity of EiE hypotheses on marine gastrotrichs, we applied Parsimony Analysis of Endemism (PAE) to identify areas of endemism. We used provinces of coastal and continental shelves of the world as operational units to define the distribution of 458 marine species of Gastrotricha. We found 10 areas of endemism, most of them were recorded from Europe and North America, and some areas were also consistent with the distribution of other benthic groups. An area of endemism is obtained when at least two species are perfectly congruent in their distribution. Moreover, the state of knowledge of the true species distribution is directly related to the intensity and spatial variation of the sampling effort. Thus, it is not a surprise to note that most areas of endemism are in the North Hemisphere, where gastrotrichs have been especially and longer sampled and their geographic range size is well known. On the other hand, the absence of endemism areas in South Hemisphere is related to sampling insufficiency. However, some level of endemism was found and the ubiquitous distribution of gastrotrich species is strongly questioned.
{"title":"Is the ubiquitous distribution real for marine gastrotrichs? Detection of areas of endemism using Parsimony Analysis of Endemicity (PAE)","authors":"A. Garraffoni, M. Balsamo","doi":"10.2988/17-00011","DOIUrl":"https://doi.org/10.2988/17-00011","url":null,"abstract":"Abstract Geographical patterns in microorganisms' distribution is a matter of intense debate. Following the assumption that “everything is everywhere” (EiE hypothesis), it is expected that microscopic animals do not have any scale spatial pattern of distribution due to high abundances, resting stages, and long-distance dispersal. Gastrotrichs are one of the most common components of the marine soft-body meiofauna. To assess the validity of EiE hypotheses on marine gastrotrichs, we applied Parsimony Analysis of Endemism (PAE) to identify areas of endemism. We used provinces of coastal and continental shelves of the world as operational units to define the distribution of 458 marine species of Gastrotricha. We found 10 areas of endemism, most of them were recorded from Europe and North America, and some areas were also consistent with the distribution of other benthic groups. An area of endemism is obtained when at least two species are perfectly congruent in their distribution. Moreover, the state of knowledge of the true species distribution is directly related to the intensity and spatial variation of the sampling effort. Thus, it is not a surprise to note that most areas of endemism are in the North Hemisphere, where gastrotrichs have been especially and longer sampled and their geographic range size is well known. On the other hand, the absence of endemism areas in South Hemisphere is related to sampling insufficiency. However, some level of endemism was found and the ubiquitous distribution of gastrotrich species is strongly questioned.","PeriodicalId":54578,"journal":{"name":"Proceedings of the Biological Society of Washington","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2017-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2988/17-00011","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46209390","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. Todaro, M. Dal Zotto, S. Bownes, R. Perissinotto
Abstract This study is part of a larger research program aimed at shedding light on meiofauna and macrofauna communities of the subtropical Eastern Province of KwaZulu-Natal, South Africa. Previous articles on the phylum Gastrotricha have detailed faunistic and preliminary taxonomic data on marine and freshwater species found in the iSimangaliso Wetland Park. Here, two new interesting marine macrodasyidan species, in the families Cephalodasyidae and Turbanellidae, are reported from a wider area of the KZN coast. Descriptions are based on observations carried out on living specimens using differential interference contrast microscopy. Pleurodasys incomptus new species is the second species in the genus; surprisingly, it lacks the peculiar gravireceptor organs (pharyngeal knobs) thought to be an autapomorphic trait of the genus. Paraturbanella africana new species is a mid-sized species (up to 520 μm in length), showing a peribuccal swelling; its most obvious autapomorphic trait pertains to the testes, which are located well passed half the body rather than at- or near the pharyngo-intestinal junction as occur in the other species of the genus. The relevant anatomical novelties shown by the two new species testify that current knowledge about gastrotrich basic morphology is far from complete. This holds true also for taxa that are considered to be well-known (e.g. the speciose genus Paraturbanella), and stresses once again the importance of investigating new geographic areas in order to improve our understanding of global gastrotrich morphological diversity and species richness.
{"title":"Two new interesting species of Macrodasyida (Gastrotricha) from KwaZulu-Natal (South Africa)","authors":"M. Todaro, M. Dal Zotto, S. Bownes, R. Perissinotto","doi":"10.2988/17-00010","DOIUrl":"https://doi.org/10.2988/17-00010","url":null,"abstract":"Abstract This study is part of a larger research program aimed at shedding light on meiofauna and macrofauna communities of the subtropical Eastern Province of KwaZulu-Natal, South Africa. Previous articles on the phylum Gastrotricha have detailed faunistic and preliminary taxonomic data on marine and freshwater species found in the iSimangaliso Wetland Park. Here, two new interesting marine macrodasyidan species, in the families Cephalodasyidae and Turbanellidae, are reported from a wider area of the KZN coast. Descriptions are based on observations carried out on living specimens using differential interference contrast microscopy. Pleurodasys incomptus new species is the second species in the genus; surprisingly, it lacks the peculiar gravireceptor organs (pharyngeal knobs) thought to be an autapomorphic trait of the genus. Paraturbanella africana new species is a mid-sized species (up to 520 μm in length), showing a peribuccal swelling; its most obvious autapomorphic trait pertains to the testes, which are located well passed half the body rather than at- or near the pharyngo-intestinal junction as occur in the other species of the genus. The relevant anatomical novelties shown by the two new species testify that current knowledge about gastrotrich basic morphology is far from complete. This holds true also for taxa that are considered to be well-known (e.g. the speciose genus Paraturbanella), and stresses once again the importance of investigating new geographic areas in order to improve our understanding of global gastrotrich morphological diversity and species richness.","PeriodicalId":54578,"journal":{"name":"Proceedings of the Biological Society of Washington","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2017-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2988/17-00010","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44748706","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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