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Peter Hovingh - One of the best experts on this subject based on the ideXlab platform.
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Freshwater leech (Annelida: Hirudinida) distribution in the Canadian Province of Newfoundland and Labrador and adjacent regions: check-list, new records, new pigmentation forms, and Pleistocene refugia
Zootaxa, 2007Co-Authors: Jacqueline Madill, Peter HovinghAbstract:The freshwater leeches (Hirudinida) in the Province of Newfoundland and Labrador were investigated by examining theliterature, the Canadian Museum of Nature and the United States National Museum of Natural History records, and aleech survey. New pigmentation forms are described for Erpobdella punctata (Leidy) and Erpobdella obscura (Verrill).This is the first published record for Haemopis lateromaculata Mathers in Canada. Four species ( Glossiphonia elegans (Verrill), Helobdella modesta (Verrill), Erpobdella punctata , and Erpobdella obscura ) were found in both Labrador andNewfoundland with Erpobdella obscura common in Labrador and the other three species common in Newfoundland.Seven other species of leeches were less abundant in Newfoundland with 6 of these species very restricted in distribution.The abundance of leech species in Newfoundland and the paucity of leech species in Labrador suggested that theisland species were present in a Pleistocene refugium associated with Newfoundland or the Grand Banks. Post-Pleistocenebarriers to leech mobility are examined, and possible timing of colonization events is proposed in this model.
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Erpobdella (Dina) parva complex (Annelida: Hirudinea: Arhynchobdellida: Erpobdellidae): additional description of Erpobdella parva, E. dubia, and E. lahontana and taxonomic revision
Hydrobiologia, 2004Co-Authors: Peter HovinghAbstract:Erpobdella ( Dina ) parva complex ( E. parva , E. dubia , and E. lahontana) were analyzed by species distribution, pigmentation, size, number and position of the labial eyes, tubercle presence, annulus width, gonopore position, and male genital atrium shape. I concluded that E. parva and E. dubia are conspecific, with the priority name of E. parva . The Lahontan basin species (E. lahontana) , was found to be distinct by gonopore position, and now includes two additional basins (Granite Springs and Winnemucca). Endemism occurred in the Relict Dace basin complex (Butte and Steptoe basins) with respect to one form of gonopore positions. The variation in pigmentation, eye position and number, gonopore position, and male genital organ shape were highly variable in the Great Basin. Examination of the annular widths did not give any guidance to the taxonomic problem of the genera of this complex. It was noted that the Erpobdella parva complex did have some similarities with Nephelopsis obscura .
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Erpobdella dina parva complex annelida hirudinea arhynchobdellida erpobdellidae additional description of Erpobdella parva e dubia and e lahontana and taxonomic revision
Hydrobiologia, 2004Co-Authors: Peter HovinghAbstract:Erpobdella (Dina) parva complex (E. parva, E. dubia, and E. lahontana) were analyzed by species distribution, pigmentation, size, number and position of the labial eyes, tubercle presence, annulus width, gonopore position, and male genital atrium shape. I concluded that E. parva and E. dubia are conspecific, with the priority name of E. parva. The Lahontan basin species (E. lahontana), was found to be distinct by gonopore position, and now includes two additional basins (Granite Springs and Winnemucca). Endemism occurred in the Relict Dace basin complex (Butte and Steptoe basins) with respect to one form of gonopore positions. The variation in pigmentation, eye position and number, gonopore position, and male genital organ shape were highly variable in the Great Basin. Examination of the annular widths did not give any guidance to the taxonomic problem of the genera of this complex. It was noted that the Erpobdella parva complex did have some similarities with Nephelopsis obscura.
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Hyaluronidase activity in leeches (Hirudinea)
Comparative Biochemistry and Physiology B, 1999Co-Authors: Peter Hovingh, Alfred LinkerAbstract:Abstract The leech hyaluronoglucuronidase (hyaluronidase I) was identified in Erpobdellidae ( Nephelopsis obscura and Erpobdella punctata ) and Glossiphoniidae ( Desserobdella picta ) and historically described from Hirudinidae ( Hirudo medicinalis ). A second leech hyaluronidase (hyaluronidase II) which hydrolyzed only a few bonds to form hyaluronan oligosaccharides larger than 6500 Da, was found in Glossiphoniidae ( Helobdella stagnalis, Glossiphonia complanata, Placobdella ornata, and Theromyzon sp.) and in Haemopidae ( Haemopis marmorata ). The distribution of the two hyaluronidases in leech occurred in both orders (Arhynchobdellida and Rhynchobdellida) and in macrophagous and haematophagous feeding types whereas the liquidosomatophagous leeches only had hyaluronidase II.
Saïda Tekaya - One of the best experts on this subject based on the ideXlab platform.
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surface ultrastructure and internal properties of the Erpobdella testacea hirudinae arynchobdellidae cocoon membrane
Micron, 2017Co-Authors: Yasmina Romdhane, Yann Quilichini, Saïda TekayaAbstract:Abstract The Erpobdella testacea cocoon membrane is studied for the first time by transmission and scanning electron microscopy. It has an ovoid form, displays a cambered dorsal side in which various micro-organisms are attached and a flattened ventral side. Symmetrically positioned, 2 opercula occur at the distal ends of the cocoon. The internal ultrastructure reveals fibrils (17.5 nm) packed in layers forming C, S, bow shaped, parallel and stippling patterns lines, interrupted by Polygon-shaped cavities (1.8 μm). Transverse sections show that each fibril presents an external dark part (6 nm) and a central hole approximately 5.06 nm in diameter. These features are discussed with bibliographic data signalized for other species. Phylogenetic and functional significations of the cocoon wall structure in leeches are suggested.
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Erpobdellid leeches (Annelida, Clitellata, Hirudinida) from Tunisia: New records with the description of a new Trocheta species
Zootaxa, 2013Co-Authors: Raja Ben Ahmed, Joanna M Cichocka, Aleksander Bielecki, Saïda Tekaya, Małgorzata Gorzel, Abdul Halim HarrathAbstract:Up to now in Tunisia, freshwater Hirudinida are represented by two mainly haematophagous families: Hirudinidae and Glossiphonidae, and a predatory one: the family Erpobdellidae. The present study provides new information on the diver-sity and taxonomy of erpobdellid leeches. Identification was based, in addition to morphological data, on the length of sperm ducts and the lengths of ovisacs in relation to the neurosomite (ns) and on the shape and size of the male atrium. Five taxons are found. Two subspecies are reported for the first time in the country: Dina punctata punctata Johansson, 1927 and Dina punctata maroccana Nesemann and Neubert, 1994. Tunisian populations of two species, Erpobdella tes-tacea (Savigny, 1820) and Trocheta africana Nesemann and Neubert, 1994, are described, with records of new localities. The new Trocheta tunisiana n. sp. is discovered and described in detail. Trocheta species live in springs in elevated areas while Erpobdella seem to prefer low altitude reservoirs. A comprehensive comparison of the three genera is presented. The disparity between the actual systematics and phylogeny is discussed. This study gives also a detailed distribution of the five species in the north of Tunisia with notes on ecological preference of the genus Dina . Finally a key for the deter-mination of freshwater erpobdellid species from Tunisia is proposed.
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an ultrastructural study of the ovary cord organization and oogenesis in Erpobdella johanssoni annelida clitellata hirudinida
Micron, 2013Co-Authors: Raja Ben Ahmed, Saïda Tekaya, Karol Malota, Piotr świątekAbstract:Abstract The aims of the present study were to analyze the ovary cord structure and oogenesis in Erpobdella johanssoni under light, fluorescent and transmission electron microscopy and to compare the obtained results with other clitellate annelids, especially with other arhynchobdellid leeches. Each of the paired ovaries is composed of the ovary wall (ovisac) and several (7–8) short, cone-shaped ovary cords. The ovary cords are of the “Erpobdella” type, i.e. they are short and polarized and five zones containing germ cells at consecutives stages of their development can be distinguished along their long axis. One, huge somatic cell (the apical cell), oogonia and premeiotic germ cells occur at the tip of the apical part of the ovary cord – zone I. Below, in zone II germ cells enter meiosis, whereas in zone III only a few cells continue meiosis and gather nutrients (oocytes), while the rest become nurse cells. In zone IV, huge vitellogenic oocytes form protuberances on the surface of the cord, and degenerating germ cells were observed at the base of the ovary cord (zones IV and V). The germline cells form syncytial cysts in zones I–III. The germline cysts have broadly the same architecture as in the ovaries of all of the clitellate annelids that have been described to date. Each germ cell in a cyst has only one cytoplasmic bridge connecting it to the common cytoplasmic mass – the cytophore. The cytophore is poorly developed, and it has the form of thin, long cytoplasmic strands. The presence of two categories of germ cells suggests a meroistic mode of oogenesis. The germline cysts are closely associated with somatic, follicular cells. There are two subpopulations of follicular cells: one envelops the growing oocytes, while the second is distributed between other germ cells. The entire ovary cord is additionally enveloped by a layer of somatic cells with a spongy appearance – the spongiosa cells. A characteristic feature of vitellogenic oocytes is the condensation of the chromosomes into a karyosome. Fully grown oocytes are excluded from the ovary cords and float freely in the ovisac lumen.
Sebastian Kvist - One of the best experts on this subject based on the ideXlab platform.
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genetic variation pseudocryptic diversity and phylogeny of Erpobdella annelida hirudinida erpobdelliformes with emphasis on canadian species
Molecular Phylogenetics and Evolution, 2020Co-Authors: Kevin Anderson, Georgina Braoudakis, Sebastian KvistAbstract:Abstract Leeches of the family Erpobdellidae are important members of benthic freshwater environments, where they are voracious predators of other invertebrates and an important source of nutrition for several species of vertebrates. Beset by a lack of reliable diagnostic morphological characters and destructive identification processes, molecular approaches have, in recent years, been employed to illuminate the relationships within this family, and DNA barcoding has been employed for identification purposes. However, an understanding of the levels of genetic variation across the geographic distributions of members of the genus is still lacking. Herein, we sequence the mitochondrial COI locus for 249 newly collected North American individuals, representing 5 species, as well as mitochondrial 12S rDNA, nuclear 18S rDNA, and nuclear 28S rDNA for a select subset of these. Our COI dataset was leveraged to detect potential cryptic species, and to calculate genetic distances as a proxy for the degree of gene flow between populations. Augmented by numerous sequences from GenBank, the multilocus dataset was used to reconstruct a phylogenetic hypothesis for worldwide members of the genus. Beyond corroborating previous overarching phylogenetic frameworks, our results show that an undescribed species that is morphologically and genetically similar to Erpobdella punctata exists in sympatry with this species – the new species has likely been overlooked in previous studies due to its morphological similarity with Erpobdella punctata. Erpobdella bucera is reported from Canada for the first time; and Erpobdella microstoma is newly reported from Saskatchewan and placed in a phylogeny for the first time. Finally, we find evidence for genetic structure in both E. cf. punctata and Erpobdella obscura that is correlated with major river drainage basin boundaries in North America.
Raja Ben Ahmed - One of the best experts on this subject based on the ideXlab platform.
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Erpobdellid leeches (Annelida, Clitellata, Hirudinida) from Tunisia: New records with the description of a new Trocheta species
Zootaxa, 2013Co-Authors: Raja Ben Ahmed, Joanna M Cichocka, Aleksander Bielecki, Saïda Tekaya, Małgorzata Gorzel, Abdul Halim HarrathAbstract:Up to now in Tunisia, freshwater Hirudinida are represented by two mainly haematophagous families: Hirudinidae and Glossiphonidae, and a predatory one: the family Erpobdellidae. The present study provides new information on the diver-sity and taxonomy of erpobdellid leeches. Identification was based, in addition to morphological data, on the length of sperm ducts and the lengths of ovisacs in relation to the neurosomite (ns) and on the shape and size of the male atrium. Five taxons are found. Two subspecies are reported for the first time in the country: Dina punctata punctata Johansson, 1927 and Dina punctata maroccana Nesemann and Neubert, 1994. Tunisian populations of two species, Erpobdella tes-tacea (Savigny, 1820) and Trocheta africana Nesemann and Neubert, 1994, are described, with records of new localities. The new Trocheta tunisiana n. sp. is discovered and described in detail. Trocheta species live in springs in elevated areas while Erpobdella seem to prefer low altitude reservoirs. A comprehensive comparison of the three genera is presented. The disparity between the actual systematics and phylogeny is discussed. This study gives also a detailed distribution of the five species in the north of Tunisia with notes on ecological preference of the genus Dina . Finally a key for the deter-mination of freshwater erpobdellid species from Tunisia is proposed.
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an ultrastructural study of the ovary cord organization and oogenesis in Erpobdella johanssoni annelida clitellata hirudinida
Micron, 2013Co-Authors: Raja Ben Ahmed, Saïda Tekaya, Karol Malota, Piotr świątekAbstract:Abstract The aims of the present study were to analyze the ovary cord structure and oogenesis in Erpobdella johanssoni under light, fluorescent and transmission electron microscopy and to compare the obtained results with other clitellate annelids, especially with other arhynchobdellid leeches. Each of the paired ovaries is composed of the ovary wall (ovisac) and several (7–8) short, cone-shaped ovary cords. The ovary cords are of the “Erpobdella” type, i.e. they are short and polarized and five zones containing germ cells at consecutives stages of their development can be distinguished along their long axis. One, huge somatic cell (the apical cell), oogonia and premeiotic germ cells occur at the tip of the apical part of the ovary cord – zone I. Below, in zone II germ cells enter meiosis, whereas in zone III only a few cells continue meiosis and gather nutrients (oocytes), while the rest become nurse cells. In zone IV, huge vitellogenic oocytes form protuberances on the surface of the cord, and degenerating germ cells were observed at the base of the ovary cord (zones IV and V). The germline cells form syncytial cysts in zones I–III. The germline cysts have broadly the same architecture as in the ovaries of all of the clitellate annelids that have been described to date. Each germ cell in a cyst has only one cytoplasmic bridge connecting it to the common cytoplasmic mass – the cytophore. The cytophore is poorly developed, and it has the form of thin, long cytoplasmic strands. The presence of two categories of germ cells suggests a meroistic mode of oogenesis. The germline cysts are closely associated with somatic, follicular cells. There are two subpopulations of follicular cells: one envelops the growing oocytes, while the second is distributed between other germ cells. The entire ovary cord is additionally enveloped by a layer of somatic cells with a spongy appearance – the spongiosa cells. A characteristic feature of vitellogenic oocytes is the condensation of the chromosomes into a karyosome. Fully grown oocytes are excluded from the ovary cords and float freely in the ovisac lumen.
Alejandro Oceguerafigueroa - One of the best experts on this subject based on the ideXlab platform.
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leeches from chiapas mexico with a new species of Erpobdella hirudinida erpobdellidae
American Museum Novitates, 2018Co-Authors: Michael Tessler, Mark E. Siddall, Alejandro OceguerafigueroaAbstract:ABSTRACT Freshwater leeches were collected from Chiapas, Mexico. Among these collections and prior records, a total of nine species were found, comprising six genera and four families. One species, Diestecostoma octannulata, represents a new record for Mexico and two species, Helobdella elongata and H. octatestisaca, represent new records for Chiapas. Additionally, a new species of Erpobdella was discovered from a single stream in the park El Arcotete near San Cristobal de las Casas. Here it is described as Erpobdella adani and it is morphologically distinguished from Mexican Erpobdella species by the combination of having the whole body strongly dorsoventrally flattened, three annuli between gonopores, an enlarged male gonopore, and no preatrial loops for the male reproductive system. Based on sequence data (mitochondrial cytochrome c oxidase subunit I and 12S; nuclear 18S), this new species appears most closely related to a clade formed by E. coastalis and E. ochoterenai. Both mitochondrial cytochrome c...