Relevant bibliographies by topics / Viviparous

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  2. Dissertations / Theses
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Academic literature on the topic 'Viviparous'

Author: Grafiati
Published: 4 June 2021
Last updated: 9 March 2023

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Journal articles on the topic "Viviparous"

1

Svedäng, H., H. Ojaveer, and E. Urtans. "Interpretation of the otolith structures in viviparous blenny Zoarces viviparus." Journal of Applied Ichthyology 13, no. 3 (October 1997): 137–42. http://dx.doi.org/10.1111/j.1439-0426.1997.tb00113.x.

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2

Fialho, Clarice Bernhardt. "Viviparous Fishes." Neotropical Ichthyology 4, no. 4 (December 2006): 462. http://dx.doi.org/10.1590/s1679-62252006000400012.

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3

Riehl, Rüdiger, and Hartmut Greven. "Fine structure of egg envelopes in some viviparous goodeid fishes, with comments on the relation of envelope thinness to viviparity." Canadian Journal of Zoology 71, no. 1 (January 1, 1993): 91–97. http://dx.doi.org/10.1139/z93-014.

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The egg envelope (zona radiata) of the full-grown oocytes before fertilization was examined by electron microscope in eight viviparous species of Goodeidae (Cyprinodontiformes) from the Mexican plateau. The egg envelope is composed of a homogeneous electron-dense zona radiata perforated mainly by oocyte microvilli. The thickness of the zona radiata ranged from 0.5 μm (Xenoophorus captivus) to 1.5 μm (Ameca splendens). Egg envelopes of Ataeniobius toweri and Ilyodon xantusi appeared to have two layers, tentatively described as a zona radiata interna and a zona radiata externa. The most complex envelope was observed in Girardinichthys multiradiatus, which showed a small filamentous zona radiata interna and an electron-dense zona radiata externa covered by an additional flocculent layer, which is probably the gelatinous coat found in many eggs. The egg envelope of Ameca splendens, Girardinichthys viviparus, and Xenotoca eiseni displayed short external processes resembling attaching filaments, which are known from eggs of substrate-spawning teleosts. The thickness and differentiation of the zona radiata in other viviparous teleosts are compared and discussed with reference to mode of reproduction.
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4

RODRÍGUEZ, SANDRA GONZÁLEZ, PAUL A. BROWN, JAIME ORTEGO, SARA I. LÓPEZ CIRUELOS, and JUAN M. NIETO NAFRÍA. "Aphis species (Hemiptera, Aphididae) living on Mulinum (Apiaceae) in South America, with a description of a new species." Zootaxa 4216, no. 1 (January 3, 2017): 47. http://dx.doi.org/10.11646/zootaxa.4216.1.2.

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Aphis species living on the South American native genus Mulinum are studied. Aphis vurilocensis Nieto Nafría, Brown and López Ciruelos, sp. n. is described from apterous viviparous females. Alate viviparous females, oviparous females and winged males of Aphis roberti are described. Knowledge of intraspecific variability of apterous viviparous females of A. martinezi, A. paravanoi and A. roberti is developed. An identification key of apterous viviparous females of Aphis species living on Mulinum is presented.
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Heulin, Benoît, Maria Jesus Arrayago, Antonio Bea, and Florentino Brana. "Caractéristiques de la coquille des oeufs chez la souche hybride (ovipare × vivipare) du lézard Lacerta vivipara." Canadian Journal of Zoology 70, no. 11 (November 1, 1992): 2242–46. http://dx.doi.org/10.1139/z92-301.

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The lizard Lacerta vivipara has both oviparous and viviparous populations. Experimental crossbreedings (oviparous strain × viviparous strain) in the laboratory have previously allowed us to obtain a hybrid strain. Hybrids have also laid eggs in the laboratory. The aim of the present study was to determine the eggshell characteristics of the hybrid and to compare them with the characteristics previously studied in the oviparous and viviparous strains. The mean thickness of the eggshell is 21 μm for the hybrid, 40 μm for oviparous eggshell, and 9 μm for the viviparous eggshell membrane. Mean dry mass of the eggshell is 3 mg for hybrids, 5 mg for the oviparous strain, and 0.6 mg for the viviparous strain. Ash mass of the eggshell is 0.79 mg for hybrids, 1.05 mg for the oviparous strain, and 0.22 mg for the viviparous strain. Fibrils were observed in both oviparous and hybrids' eggshells and in the viviparous eggshell membrane. The outer surface of the hybrids' eggs presents both places with a calcareous layer (61%) and places where fibrils are not covered with a calcareous layer (39%). These incompletely calcified eggshells are intermediate between the oviparous eggshells (complete calcareous layer) and the regressed eggshell membrane (fibrils with minor traces of calcite) observed during the gestation of the viviparous lizards. This situation is of considerable interest for further experimental studies dealing with physiological and genetic aspects of the evolution of viviparity.
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Puizina, Jasna, Branka Javornik, Borut Bohanec, Dieter Schweizer, Jolanta Maluszynska, and Drazena Papeš. "Random amplified polymorphic DNA analysis, genome size, and genomic in situ hybridization of triploid viviparous onions." Genome 42, no. 6 (December 1, 1999): 1208–16. http://dx.doi.org/10.1139/g99-023.

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Triploid viviparous onions (Allium cepa L. var. viviparum Metzg. (ALEF.), auct.), (2n = 3x = 24), are known in some countries only as a rare relic crop, while in other parts of the world they are still traditionally or even commercially cultivated. Results indicating an identical random amplified polymorphic DNA (RAPD) banding pattern and the same DNA content (2C = 43.4 pg) establish the high genetic similarity and the unique origin of the Croatian clone Ljutika and the Indian clone Pran. In order to determine the parental Allium species of these natural triploid hybrids, genomic fluorescent in situ hybridization (GISH) was applied. Biotinylated genomic DNAs from six diploid Allium species (A. cepa L., A. fistulosum L., A. roylei Stearn, A. vavilovii M. Pop. et Vved., A. galanthum Kar. et Kir., A. oschaninii O. Fedtsch.) were used as probes in this study. While probes obtained from genomic DNA of A. cepa, A. vavilovii, and A. roylei hybridized to somatic chromosomes of Ljutika probes from A. fistulosum, A. galanthum, and A. oschaninii did not. The DNA probes of A. cepa and A. roylei each completely or predominantly labelled one genome (eight chromosomes). A few chromosomes, the markers of the triploid karyotype, were not completely labelled by any probe applied. Our GISH results indicate that triploid viviparous onions might possess a complex triparental genome organization.Key words: triploid viviparous onions, Allium cepa, Allium roylei, genomic in situ hybridization, genome size, random amplified polymorphic DNA (RAPD).
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7

Barjadze, Shalva, and Nana Gratiashvili. "Description of a new species of the genus Macrosiphum Passerini, 1860 (Hemiptera: Aphidoidea: Aphididae), with a key to the Macrosiphum species occurring in Transcaucasia." Entomologica Fennica 21, no. 1 (August 14, 2019): 43–48. http://dx.doi.org/10.33338/ef.84497.

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Apterous viviparous females of Macrosiphum dzhibladzeae Barjadze sp. n. living on Euphorbia macroceras (Euphorbiaceae) are described and illustrated. A key to the apterous viviparous females of Macrosiphum species living on Euphorbia spp. worldwide is given. A previous key for the apterous viviparous females of the Macrosiphum species recorded from Transcaucasia is provided, modified to include the new species.
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NAFRÍA, JUAN M. NIETO, NICOLÁS PÉREZ HIDALGO, SERGIO GARCÍA-TEJERO, SARA I. LÓPEZ CIRUELOS, and M. PILAR MIER DURANTE. "Contribution to the knowledge of North-American species Hyperomyzus subgenus Neonasonovia (Aphididae, Aphidinae, Macrosiphini)." Zootaxa 4294, no. 2 (July 18, 2017): 241. http://dx.doi.org/10.11646/zootaxa.4294.2.7.

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American specimens of the Hyperomyzus subgenus Neonasonovia conserved in the collections of the Muséum national d’Histoire naturelle (Paris, France) and the Natural History Museum (London, United Kingdom), have been studied. Data to complement previous descriptions of apterous and alate viviparous females of H. nabali and of apterous viviparae of H. nigricornis, H. inflatus, H. niger and H. pullatus, are presented. Apterous and alate virginogeniae females of H. nigricornis, alate viviparous females of H. inflatus, H. niger and H. pullatus, plus oviparous females of H. nabali, are described for the first time. The morphological and biological variability of H. pullatus is discussed. An identification key for viviparous females of the American species of Neonasonovia is presented for the first time. Microphotographs of apterous and alate viviparous females of H. nabali, H. nigricornis, H. inflatus and H. niger, alate viviparous females of H. pullatus, and oviparous female of H. nabali, are presented.
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BARJADZE, SHALVA, IŞIL ÖZDEMIR, and EBRAHIM EBRAHIMI. "Two species of Brachyunguis (Hemiptera: Aphididae) new to Iran, and a key to the Iranian species of this genus." Zootaxa 5183, no. 1 (September 12, 2022): 49–57. http://dx.doi.org/10.11646/zootaxa.5183.1.6.

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Brachyunguis dendrostellerae Kadyrbekov, 2014 and B. monstratus Kadyrbekov, 1999, both living on Diarthron lessertii (Wikstr.) Kit Tan. (Thymelaeaceae), are recorded for Iranian aphid fauna for the first time. The hitherto unknown alate viviparous females of B. dendrostellerae are described, and the little-known apterous viviparous females are redescribed. An identification key for apterous viviparous females of Brachyunguis species known from Iran is provided.
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STASIAK, Aleksandra K. "PROPOSAL OF THE MONITORING METHODOLOGY OF THE VIVIPAROUS LIZARD Zootoca vivipara." Folia Pomeranae Universitatis Technologiae Stetinensis Agricultura, Alimentaria, Piscaria et Zootechnica 362, no. 61 (March 31, 2022): 15–24. http://dx.doi.org/10.21005/aapz2022.61.1.02.

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The viviparous lizard (Zootoca vivipara) is a species of the Squamata order from the family of lizards (Lacertidae) covering the wide range – from Western Europe, including British islands and Ireland to the far reaches of Asia with limit of occurrence on the Japanese island of Hokkaido. The population of the viviparous lizard is not regularly monitored and does not have specific monitoring rules. Currently, numerous publications in the press and media inform about the progressive intensification of agriculture, intensity of tourist traffic or the increasingly progressive urbanization of the environment, which contributes to the migration of viviparous lizards from these areas. It has been suggested that because of human interference with the environment, viviparous lizards retreat to intact natural habitats. This is related to decrease in the area of occurrence of these reptiles and less frequent observations than before. The work presents a proposed methodology of viviparous lizard monitoring based on the evaluation of population status indicator – relative abundance and habitat condition indicators such as availability of breeding places and availability of hiding places. The aim of the article is to present indicators of the population status and habitat condition indicators, additionally to establish terms and frequency of surveys within the framework of the possibility to conduct monitoring studies of viviparous lizard populations.
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Dissertations / Theses on the topic "Viviparous"

1

Oehninger-Storvoll, Karen-Christine. "Stress influence of offshore wind farms on the reproduction of the viviparous eelpout (Zoarces viviparus)." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for marin teknikk, 2013. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-21415.

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Okende behov for fornybar energi har skapt en økning av installasjoner for fornybar marin energi. Disse installasjonene varierer fra bølge- og tidevannskraft til offshore vindkraft. Påvirkning av offshore vindkraft på fiskearten ålekvabbe (<i>Zoarces viviparus</i>) i Ostersjøen har blitt undersøkt i denne studien. I løpet av to feltsesonger (oktober 2011 og 2012) ble gravide hunnfisk fanget ved Lillgrund vindkraftpark (Breddegrad 55°, lengdegrad 12°.), samt ved en kontrollokaliten Bredgrund. Fiskens lengde (TL), totalvekt, gonade- og levervekt ble målt samt antall yngel, lengde på yngel, kjønnsfordeling og yngelens overlevelse ble registrert. Resultatene viser at hunner fra vindkraftparken er i bedre kondisjon og har fler samt større yngel enn i kontrollokaliteten. Denne studien viser også hvordan år kan påvirke alle disse trekkene og hvordan det gjør det viktig å ha data fra flere år samt lokaliteter i fremtidige studier når påvirkninger av vindkraft skal bedømmes.
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2

Robert, Kylie. "Temperature-dependent sex determination in the viviparous lizard, Eulamprus tympanum." Connect to full text, 2003. http://hdl.handle.net/2123/557.

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Thesis (Ph. D.)--University of Sydney, 2004.
Title from title screen (viewed 5 May 2008). Submitted in fulfilment of the requirements for the degree of Doctor of Philosophy to the School of Biological Sciences, Faculty of Science. Degree awarded 2004; thesis submitted 2003. Appendices contains published articles co-authored by Robert. Includes bibliographical references. Also available in print form.
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3

Robert, Kylie Anne. "Temperature-dependent sex determination in the viviparous lizard Eulamprus tympanum." Thesis, The University of Sydney, 2003. http://hdl.handle.net/2123/557.

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Abstract There are a remarkable variety of sex determination systems among different animal taxa. In most animals, sex is determined chromosomally. Although in an increasing number of animals sex determination has been found to be influenced primarily by the environment. Species with genotypic sex determination (GSD) have their sex determined at the time of fertilization, by genetic factors alone and those with environmental sex determination (ESD) have their sex determined by environmental factors that act after fertilization. Temperature-dependent Sex Determination (TSD), whereby the sex of the developing embryos depends on the temperature at which they develop is widespread in oviparous reptiles and occurs in all crocodilians, marine turtles and tuatara examined to date and is common in many freshwater turtles and lizards. SECTION ONE Temperature-dependent sex determination (TSD) was never expected to occur in viviparous reptiles, as thermoregulation by pregnant females would result in relatively stable gestation temperatures. Temperature-dependent sex determination and viviparity goes against all the basic assumptions that TSD occurs in oviparous reptiles where temperatures within a nest vary widely. However, skewed sex ratios as a result of incubation temperature indicated the possibility of TSD in the viviparous lizard Eulamprus tympanum. In my first experiments I show the first recorded case of a viviparous reptile with TSD. The developing embryos of the viviparous skink E. tympanum are subject to TSD, with gestation temperature having a highly significant effect on sex and warmer temperatures giving rise to male offspring (Chapter 1). Sex is fully determined at the time of birth and can be differentiated histologically into testes or ovaries (Chapter 2). The morphology and histological characteristics of the gonads of neonatal E. tympanum resulting from the treatment temperatures described in chapter 1 illustrate that sex in E. tympanum is easily distinguished at the time of birth and corresponds with the presence or absence of hemipenes. Males are histologically characterised by an elongated gonad consisting of seminiferous tubules with either no cortical epithelium or, if present at all, in a very thin band. If they are present, Mϋllerian ducts, showing signs of degeneration, are attached to the kidney by a shortened mesosalpinx. Females are histologically characterised by an irregularly shaped gonad consisting of a thick cortical epithelium that occasionally contains oocytes. The Mϋllerian ducts are obvious structures attached to the kidney by a fibrous mesosalpinx. The presence or absence of hemipenes is a reliable technique for determining sex in newborn E. tympanum. Sex determination is easiest to perform on neonates within the first few days of birth as hemipenes become increasingly difficult to evert as neonates age, however, with practice they are easily identified without full eversion. SECTION TWO The thermal biology of E. tympanum in the field is restricted by both the thermal properties of their habitat (Chapter 3) and behavioural modifications when faced with a predation threat (Chapter 4). The available temperatures in the field suggest that TSD is biologically relevant in the species and not just a laboratory artefact; E. tympanum can attain mean selected temperatures achieved in the laboratory but the proportion of time at the temperature is restricted. Females actively thermoregulate in the field, although they are restricted in their efficiency of thermoregulation by environmental constraints, for example, microhabitat structure, weather conditions, predator avoidance and social ranking. The highly territorial nature and high densities of E. tympanum present in Kanangra Boyd National Park potentially force less dominant individuals into less favourable habitats that are significantly cooler. An important point is that gravid females in more favourable habitats in the period encompassing the middle third of development (the assumed sex determining period) are selecting higher temperatures, with lower variance and have greater thermoregulatory efficiency than during the rest of pregnancy, therefore, thermoregulating more precisely during this thermosensitive period (Chapter 3). Chemosensory cues provide important information on the risk of predation. Hence, chemoreception is a common mechanism used by many species to detect the presence of, and subsequently respond to, a potential predator. The perceived risk of predation may force retreat to sub-optimal conditions, forcing a trade-off between the risk of predation and the ability to acquire resources. The basking regime maintained by gravid female E. tympanum, can directly alter sex ratios of offspring produced through temperature-dependent sex determination (Chapter 1). The avoidance of predator scents may restrict basking ability and in turn alter the sex of offspring produced. I measured responsiveness to chemical cues using tongue flicks as an indicator of chemical discrimination in females of different reproductive condition. I then measured activity and basking behaviour of gravid and non-gravid females in experimental enclosures in the presence of various chemical stimuli to determine if basking opportunity is compromised by the presence of a predator scent. Females respond differently depending upon reproductive condition, with gravid females responding most significantly to a predator scent. Activity, basking frequency, and time spent in the open (basking duration) are significantly reduced in gravid females in the presence of a predator stimulus. Under laboratory conditions, gravid females modify their behaviour and forego the opportunity to bask when there is a perceived predation risk (Chapter 4). SECTION THREE As female viviparous reptiles can regulate the temperature of the embryo by maternal temperature selection (Chapter 1), the occurrence of TSD in E. tympanum opens the possibility for females to select the sex of offspring. Reproducing females may benefit by facultatively adjusting their investment into sons over daughters or vice versa, in response to population wide shifts in adult sex ratios. Female E. tympanum, can manipulate the sex of their offspring in response to sex imbalances in the population using temperature-dependent sex determination (Chapter 5). When adult males are scarce, females produce male-biased litters and when adult males are common, females produce female-biased litters. The cues used by a female to assess the adult population are not known, but presumably depends upon the female's experience throughout the breeding season and is the subject of further investigation (Chapter 6). The maternal manipulation of offspring sex ratio in E. tympanum suggests a selective advantage of temperature-dependent sex determination. Any facultative sex ratio response needs to recognise the scarcity of one sex in order to overproduce that sex in the next generation; offspring sex ratio will vary inversely with adult sex ratio. Maternal sex allocation in E. tympanum is linked with population (or adult) sex ratio (Chapter 5), and one of the mechanisms by which females recognise an imbalance may be linked to visual recognition of males (Chapter 6). Females maintained throughout pregnancy without any male stimulus produce entirely male offspring (Chapter 5). In contrast females exposed to male stimulus produce both sexes (Chapter 5). Females respond differently to varying degrees of male stimulus and visual recognition of males in a population may be more important than chemoreception. In the absence of visual cues, females produce more male offspring, even when chemosensory cues are present (Chapter 6). The study system presented here offers many advantages over oviparous species with TSD, due to E. tympanum being relatively short lived and fast maturing. Thus, the fitness consequences over multiple generations as a result of gestation can be investigated. Viviparity allows maternal control of embryonic temperature during gestation and a means of maternal sex allocation. Until now the maternal side of TSD and sex allocation has been where the mother deposits her eggs and the allocation of sex steroid hormones at oviposition, both of which have been difficult to study. The work presented and the study system itself should inspire great interest in TSD and viviparous reptiles.
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4

Robert, Kylie Anne. "Temperature-dependent sex determination in the viviparous lizard Eulamprus tympanum." University of Sydney. Biological Science, 2003. http://hdl.handle.net/2123/557.

Full text
Abstract:
Abstract There are a remarkable variety of sex determination systems among different animal taxa. In most animals, sex is determined chromosomally. Although in an increasing number of animals sex determination has been found to be influenced primarily by the environment. Species with genotypic sex determination (GSD) have their sex determined at the time of fertilization, by genetic factors alone and those with environmental sex determination (ESD) have their sex determined by environmental factors that act after fertilization. Temperature-dependent Sex Determination (TSD), whereby the sex of the developing embryos depends on the temperature at which they develop is widespread in oviparous reptiles and occurs in all crocodilians, marine turtles and tuatara examined to date and is common in many freshwater turtles and lizards. SECTION ONE Temperature-dependent sex determination (TSD) was never expected to occur in viviparous reptiles, as thermoregulation by pregnant females would result in relatively stable gestation temperatures. Temperature-dependent sex determination and viviparity goes against all the basic assumptions that TSD occurs in oviparous reptiles where temperatures within a nest vary widely. However, skewed sex ratios as a result of incubation temperature indicated the possibility of TSD in the viviparous lizard Eulamprus tympanum. In my first experiments I show the first recorded case of a viviparous reptile with TSD. The developing embryos of the viviparous skink E. tympanum are subject to TSD, with gestation temperature having a highly significant effect on sex and warmer temperatures giving rise to male offspring (Chapter 1). Sex is fully determined at the time of birth and can be differentiated histologically into testes or ovaries (Chapter 2). The morphology and histological characteristics of the gonads of neonatal E. tympanum resulting from the treatment temperatures described in chapter 1 illustrate that sex in E. tympanum is easily distinguished at the time of birth and corresponds with the presence or absence of hemipenes. Males are histologically characterised by an elongated gonad consisting of seminiferous tubules with either no cortical epithelium or, if present at all, in a very thin band. If they are present, M�llerian ducts, showing signs of degeneration, are attached to the kidney by a shortened mesosalpinx. Females are histologically characterised by an irregularly shaped gonad consisting of a thick cortical epithelium that occasionally contains oocytes. The M�llerian ducts are obvious structures attached to the kidney by a fibrous mesosalpinx. The presence or absence of hemipenes is a reliable technique for determining sex in newborn E. tympanum. Sex determination is easiest to perform on neonates within the first few days of birth as hemipenes become increasingly difficult to evert as neonates age, however, with practice they are easily identified without full eversion. SECTION TWO The thermal biology of E. tympanum in the field is restricted by both the thermal properties of their habitat (Chapter 3) and behavioural modifications when faced with a predation threat (Chapter 4). The available temperatures in the field suggest that TSD is biologically relevant in the species and not just a laboratory artefact; E. tympanum can attain mean selected temperatures achieved in the laboratory but the proportion of time at the temperature is restricted. Females actively thermoregulate in the field, although they are restricted in their efficiency of thermoregulation by environmental constraints, for example, microhabitat structure, weather conditions, predator avoidance and social ranking. The highly territorial nature and high densities of E. tympanum present in Kanangra Boyd National Park potentially force less dominant individuals into less favourable habitats that are significantly cooler. An important point is that gravid females in more favourable habitats in the period encompassing the middle third of development (the assumed sex determining period) are selecting higher temperatures, with lower variance and have greater thermoregulatory efficiency than during the rest of pregnancy, therefore, thermoregulating more precisely during this thermosensitive period (Chapter 3). Chemosensory cues provide important information on the risk of predation. Hence, chemoreception is a common mechanism used by many species to detect the presence of, and subsequently respond to, a potential predator. The perceived risk of predation may force retreat to sub-optimal conditions, forcing a trade-off between the risk of predation and the ability to acquire resources. The basking regime maintained by gravid female E. tympanum, can directly alter sex ratios of offspring produced through temperature-dependent sex determination (Chapter 1). The avoidance of predator scents may restrict basking ability and in turn alter the sex of offspring produced. I measured responsiveness to chemical cues using tongue flicks as an indicator of chemical discrimination in females of different reproductive condition. I then measured activity and basking behaviour of gravid and non-gravid females in experimental enclosures in the presence of various chemical stimuli to determine if basking opportunity is compromised by the presence of a predator scent. Females respond differently depending upon reproductive condition, with gravid females responding most significantly to a predator scent. Activity, basking frequency, and time spent in the open (basking duration) are significantly reduced in gravid females in the presence of a predator stimulus. Under laboratory conditions, gravid females modify their behaviour and forego the opportunity to bask when there is a perceived predation risk (Chapter 4). SECTION THREE As female viviparous reptiles can regulate the temperature of the embryo by maternal temperature selection (Chapter 1), the occurrence of TSD in E. tympanum opens the possibility for females to select the sex of offspring. Reproducing females may benefit by facultatively adjusting their investment into sons over daughters or vice versa, in response to population wide shifts in adult sex ratios. Female E. tympanum, can manipulate the sex of their offspring in response to sex imbalances in the population using temperature-dependent sex determination (Chapter 5). When adult males are scarce, females produce male-biased litters and when adult males are common, females produce female-biased litters. The cues used by a female to assess the adult population are not known, but presumably depends upon the female�s experience throughout the breeding season and is the subject of further investigation (Chapter 6). The maternal manipulation of offspring sex ratio in E. tympanum suggests a selective advantage of temperature-dependent sex determination. Any facultative sex ratio response needs to recognise the scarcity of one sex in order to overproduce that sex in the next generation; offspring sex ratio will vary inversely with adult sex ratio. Maternal sex allocation in E. tympanum is linked with population (or adult) sex ratio (Chapter 5), and one of the mechanisms by which females recognise an imbalance may be linked to visual recognition of males (Chapter 6). Females maintained throughout pregnancy without any male stimulus produce entirely male offspring (Chapter 5). In contrast females exposed to male stimulus produce both sexes (Chapter 5). Females respond differently to varying degrees of male stimulus and visual recognition of males in a population may be more important than chemoreception. In the absence of visual cues, females produce more male offspring, even when chemosensory cues are present (Chapter 6). The study system presented here offers many advantages over oviparous species with TSD, due to E. tympanum being relatively short lived and fast maturing. Thus, the fitness consequences over multiple generations as a result of gestation can be investigated. Viviparity allows maternal control of embryonic temperature during gestation and a means of maternal sex allocation. Until now the maternal side of TSD and sex allocation has been where the mother deposits her eggs and the allocation of sex steroid hormones at oviposition, both of which have been difficult to study. The work presented and the study system itself should inspire great interest in TSD and viviparous reptiles.
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5

Baker, Melia. "Skeletal Development in Oviparous and Viviparous Populations of Saiphos equalis." Digital Commons @ East Tennessee State University, 2011. https://dc.etsu.edu/honors/129.

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6

Macias, Garcia Constantino de Jesus. "Sexual behaviour and trade-offs in the viviparous fish Girardinichthys multiradiatus." Thesis, University of East Anglia, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.279739.

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7

Härkönen, L. (Laura). "Seasonal variation in the life histories of a viviparous ectoparasite, the deer ked." Doctoral thesis, Oulun yliopisto, 2012. http://urn.fi/urn:isbn:9789514298967.

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Abstract The life histories of ectoparasites are shaped by both host and off-host environment. A suitable host is primarily needed during reproduction, whereas juvenile stages outside the host are directly exposed to environmental variability. Viviparity, i.e. the development of an embryo inside the body of the mother resulting in large offspring size, increases offspring survival. The production of large offspring has its consequences in terms of high variation in offspring age and in the environment that each young individual will face. I used a viviparous ectoparasite, the deer ked (Lipoptena cervi), to investigate the consequences of long reproductive lifespan and varying offspring environment on offspring life-histories and seasonal adaptations. Offspring life-histories varied seasonally. I showed that the resources provided by the deer ked females determine offspring performance throughout its off-host period. Offspring size increased towards the spring and the end of the reproductive period, and simultaneously offspring survival and cold tolerance increased. Seasonal variation in offspring size did not reflect the resources that would guarantee offspring survival during the longest diapause or the highest cold tolerance during the harshest winter period. Diapause intensity varies with birth time according to the expected length of the winter ahead. However, the deer ked pupae, regardless of their age, overwinter at an opportunistic diapause, which may be terminated rapidly only by an exposure to high temperature. Contrary to general observations, photoperiod has no role in regulating the seasonal shifts of the deer ked. Neither is high cold tolerance associated only with diapause, but it remains high through four seasons, also in the active developmental and adult stages. I also evaluated the effects of life-history variation on the invasion potential of the deer ked. I conducted a large-scale transplant experiment to test the survival and pupal development at and beyond the current range. I found that the lower spring and summer temperatures and the shorter growth season in the north cause a deterioration in pupal performance and shorten the flight period. However, the colder climate may not totally prevent further spread. A more important factor that will affect deer ked invasion is host availability, and especially in Finland, the density of the moose population. Seasonal variation in offspring life histories in viviparous ectoparasites differs from the variation patterns reported in most invertebrates. This may be due to the extremely large offspring size and to the fact that maternally derived resources determine offspring performance through the entire off-host period. Variation in offspring performance is thus determined by maternal resources and seasonal variation in the condition of the moose
Tiivistelmä Useimpien ulkoloisten elinkierto on riippuvainen isännästä ja isännän ulkopuolella kasvavien jälkeläisten kohtaamista ympäristöoloista. Viviparia eli jälkeläisen kehitys naaraan sisällä ja siitä usein seuraava suuri jälkeläiskoko parantavat jälkeläisten selviytymistä. Suurten jälkeläisten tuottaminen pitkällä aikavälillä johtaa siihen, että eri-ikäiset jälkeläiset kohtaavat vuodenajasta riippuen hyvin erilaiset olosuhteet. Väitöstyössäni tarkastelin Suomessa nopeasti yleistyneen hirvieläinten ulkoloisen, hirvikärpäsen (Lipoptena cervi), avulla, mitä seurauksia viviparialla, pitkällä lisääntymiskaudella ja ympäristön vuodenaikaisvaihtelulla on jälkeläisten elinkierto-ominaisuuksiin. Väitöskirjatyössäni havaitsin, että hirvikärpäsjälkeläisten elinkiertopiirteet vaihtelevat jälkeläisen syntymäajan mukaan. Osoitin myös, että hirvikärpäsnaaraan jälkeläisilleen tarjoamat ravintovarat määrittelevät jälkeläisten isännästä riippumattoman elinkierron aikaisen menestyksen. Jälkeläisten keskimääräinen koko kasvoi lisääntymiskauden edetessä talvesta kohti kevättä, jolloin myös selviytyminen ja kylmänsietokyky paranivat. Jälkeläiskoon vuodenaikaisvaihtelu ei näin ollen vastaa jälkeläisten tarvitsemia resursseja suhteessa talvehtimisen pituuteen eikä korreloi koville talvipakkasille altistumisen todennäköisyyden kanssa. Lepotilan keston määrittelevä diapaussin syvyys vaihteli syntymävuodenaikaa vastaavasti. Diapaussin havaitsin kuitenkin olevan ensisijaisesti opportunistinen, jolloin pelkästään korkea lämpötila voi nopeasti päättää lepotilan kaikenikäisillä yksilöillä. Vastoin yleisiä käsityksiä valorytmi ei vaikuta diapaussin säätelyyn. Vastoin ennakko-odotuksia kylmänsietokyky säilyy korkeana vuoden ympäri ja kaikissa tutkituissa elinkierron vaiheissa. Sovelsin tutkimieni elinkiertopiirteiden vaikutusta myös lajin invaasiokykyyn, ja tutkin istutuskokeen avulla koteloiden selviytymistä ja kehitystä nykyisellä esiintymisalueella ja sen pohjoispuolella. Alhaisemmat kevät- ja kesälämpötilat sekä lyhyempi kasvukausi vähentävät aikuiseksi selviytymistä ja lyhentävät lentoaikaa syksyllä. Ilmastotekijöiden suhteen hirvikärpänen voisi esiintyä nykyistä pohjoisempana. Tärkein tekijä hirvikärpäsen leviämistä tarkasteltaessa on kuitenkin sopivien isäntäeläimien saatavuus ja Suomen oloissa erityisesti hirven eli hirvikärpäsen pääisännän kannan tiheys. Tutkimukseni perusteella ulkoloisten vivipariasta seuraava jälkeläisten elinkiertopiirteiden ajallinen vaihtelu eroaa muiden selkärangattomien vastaavasta vaihtelusta. Yhtenä syynä eroihin lienee se, että hirvikärpäsnaaras tuottaa erityisen suuria jälkeläisiä ja että jälkeläiset puolestaan ovat täysin riippuvaisia emon antamista resursseista. Emon lisääntymisresurssit ja hirven kunnon vuodenaikaisvaihtelu vaikuttavat mahdollisesti siihen, minkälaisia jälkeläisiä hirvikärpänen milloinkin kykenee tuottamaan
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Tedder, Amanda, Rebecca Pyles, and James R. Stewart. "Impact of viviparity on skeletal development in a reproductively bimodal squamate species." Digital Commons @ East Tennessee State University, 2018. https://dc.etsu.edu/asrf/2018/schedule/53.

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Among vertebrates, oviparous animals lay eggs with a calcified eggshell and eggs are laid in an external environment, while viviparous animals retain eggs in oviduct until they give birth to live young. Viviparity has evolved in the lineage of snakes and lizards (squamates) over 100 times, more than all other vertebrate groups. Embryos of oviparous squamates obtain calcium from both yolk and eggshell while their viviparous counterparts lack a calcified eggshell and must obtain their calcium solely from yolk, or from yolk plus placental transfer. During embryonic development, squamates rely on calcium to build the skeleton before hatching. The extent of skeletal ossification at hatching or birth varies considerably among vertebrates. This study aims to determine if skeletal development/ossification varies in association with reduced eggshell calcium in embryos of viviparous squamate species. We studied the amount of ossification and overall size of embryos and hatchlings from an oviparous and a viviparous population of the reproductively bimodal lizard Zootoca vivipara. Previous studies suggested that limb development is delayed, and that overall size is reduced in viviparous squamates. We tested the hypothesis that viviparous embryos and hatchlings are more skeletally immature and smaller in size than oviparous embryos and hatchlings in squamates. To achieve this, specimens from both populations, spanning multiple stages of embryonic development including hatchlings, were cleared & stained to reveal skeletal cartilage and bone. Lengths of total body, humerus, femur, skull and Meckel’s cartilage were measured from photographs of cleared & stained specimens taken with a Cannon EOS 70D camera on a Motic, Leica MZ9 Compound Microscope, with a measurement reference in each picture. Photos were calibrated to the measurement reference and total length measurements were obtained using iSolutionLite® software. In addition to total measurements, the lengths of ossified portions on the humerus and femur were also measured. Preliminary results revealed that total length of the skull and body are reduced in embryos and hatchlings of viviparous specimens. Total length of the limbs and of Meckel’s cartilage are not significantly different between populations. However, it appears that the amount of ossification in the limbs is reduced in oviparous specimens. These preliminary findings do not support our hypothesis and indicate that reduction in eggshell calcium in embryos of viviparous populations does not negatively impact ossification during development but does influence overall size.
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Fregoso, Santiago. "Pattern and Mechanism of Calcium Mobilization During Embryonic Development in a Viviparous Snake, Virginia striatula." Digital Commons @ East Tennessee State University, 2010. https://dc.etsu.edu/etd/1712.

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Yolk supplies the majority of embryonic calcium in snakes. Oviparous and viviparous snakes also receive calcium late in development from the eggshell and placenta, respectively. The pattern and mechanism of calcium transport are partly understood for oviparous snakes. I studied a viviparous snake, Virginia striatula, to determine the pattern of embryonic calcium accumulation as well as the ontogenetic expression of calcium transporting proteins in extraembryonic tissues. The pattern of embryonic calcium uptake of V. striatula occurs late in development, during the phase of highest embryonic growth. Calbindin-D28k, Ca2+ ATPase, and carbonic anhydrase II are expressed in chorioallantoic membrane, while yolk sac only expresses calbindin-D28k, coincident with the timing of calcium transport in embryos of V. striatula. Thus, the pattern of embryonic calcium accumulation in V. striatula is similar to that of oviparous snakes. Although calbindin-D28k and Ca2+ ATPase are likely active in embryonic calcium transport, the role of carbonic anhydrase II remains less clear.
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Spindle, S. Tyler. "Confocal Microscopy Study of the Embryonic Development of the Viviparous Nemertean Prosorhochmus americanus Reveals Larval Features Supporting Indirect Development In Hoplonemerteans." VCU Scholars Compass, 2013. http://scholarscompass.vcu.edu/etd/3186.

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Recent studies of hoplonenemertean planuliform larvae have clarified their development and provided insight into larval evolution within the phylum. However, an assessment of viviparous development using modern techniques is lacking. To help facilitate a comprehensive comparative evaluation of developmental diversity within hoplonemerteans, we have conducted a confocal laser scanning microscopy investigation of the development in Prosorhochmus americanus, one of the few viviparous hoplonemertean species. Phalloidin staining provides evidence of a modified transitory larval epidermis, and reveals that the foregut, midgut, proboscis, central nervous system, and body wall musculature form early in development, consistent with observations for planktonic and encapsulated hoplonemertean larvae. However, invaginations characteristic of these larvae were not observed. Acetylated tubulin labeling and light microscopy shows that embryos are uniformly ciliated, and some specimens possess a caudal ciliary cirrus and/or apical tuft which are characteristic of planktonic larvae. These are interpreted as vestigial structures in the non-swimming P. americanus embryos. The findings provide additional evidence that hoplonemerteans exhibit a form of metamorphosis in their life history and thus exhibit indirect development. However, a comparative assessment of larval features in P. americanus suggests an evolutionary trend towards direct development in this species.
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Books on the topic "Viviparous"

1

Mun, Wŏn-gyŏng. T'aesaengjŏk wihŏm sahoe: Viviparous risk society! Kyŏnggi-do P'aju-si: Hakhyŏnsa, 2021.

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Constantino de Jesus Macias Garcia. Sexual behaviour and trade-offs in the viviparous fish 'Girardinichthys multiradiatus'. Norwich: University of East Anglia, 1990.

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Rickling, Susanne. Vergleichende Untersuchungen zur Genexpression persistierender und nicht persistierender Stadien von Dictyocaulus viviparus. [S.l.]: [s.n.], 1999.

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Chernogorenko, E. V. On the species composition of Viviparids: (Gastropoda, Viviparidae) in Europe and western Asia. Cambridge, Mass: Dept. of Mollusks, Museum of Comparative Zoology, Harvard University, 1992.

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Zúñiga-Vega, J. Jaime, Bart Pollux, Jerald B. Johnson, and Andrea S. Aspbury, eds. Ecology, Evolution, and Behavior of Viviparous Fishes. Frontiers Media SA, 2022. http://dx.doi.org/10.3389/978-2-88974-513-5.

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Cowley, Joy. Where Are You From: Oviparous/Viviparous Animals. ChoiceMaker Pty. Limited, The, 2016.

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Kim, In-sook. Where Are You From?: Oviparous/Viviparous Animals. Big & Small, 2017.

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John James 1785-1851 N. 790 Audubon. Viviparous Quadrupeds of North America; Vol 3. Creative Media Partners, LLC, 2021.

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Where Are You From?: Oviparous/Viviparous Animals. Big & Small, 2017.

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John James 1785-1851 N. 790 Audubon. Viviparous Quadrupeds of North America; Vol 2. Creative Media Partners, LLC, 2021.

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Book chapters on the topic "Viviparous"

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Heppner, John B., John B. Heppner, John L. Capinera, Jamie Ellis, Andrey N. Alekseev, Phyllis G. Weintraub, John L. Capinera, et al. "Viviparous." In Encyclopedia of Entomology, 4131. Dordrecht: Springer Netherlands, 2008. http://dx.doi.org/10.1007/978-1-4020-6359-6_3991.

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Coad, Brian W. "Family Bythitidae – Viviparous Brotulas, Donzelles vivipares." In Marine Fishes of Arctic Canada, edited by Brian W. Coad and James D. Reist, 376–77. Toronto: University of Toronto Press, 2017. http://dx.doi.org/10.3138/9781442667297-054.

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Kardel, Troels, and Paul Maquet. "XXVI Observations Concerning the Eggs of Viviparous Animals." In Nicolaus Steno, 611–20. Berlin, Heidelberg: Springer Berlin Heidelberg, 2012. http://dx.doi.org/10.1007/978-3-642-25079-8_38.

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Kardel, Troels, and Paul Maquet. "2.26 Observations Concerning the Eggs of Viviparous Animals." In Nicolaus Steno, 751–62. Berlin, Heidelberg: Springer Berlin Heidelberg, 2018. http://dx.doi.org/10.1007/978-3-662-55047-2_37.

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Kardel, Troels, and Paul Maquet. "XXV Anatomical Observations Concerning the Eggs of Viviparous Animals." In Nicolaus Steno, 603–9. Berlin, Heidelberg: Springer Berlin Heidelberg, 2012. http://dx.doi.org/10.1007/978-3-642-25079-8_37.

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Kardel, Troels, and Paul Maquet. "2.25 Anatomical Observations Concerning the Eggs of Viviparous Animals." In Nicolaus Steno, 741–49. Berlin, Heidelberg: Springer Berlin Heidelberg, 2018. http://dx.doi.org/10.1007/978-3-662-55047-2_36.

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Blackburn, Daniel G., and Laurie J. Vitt. "Reproduction in Viviparous South American Lizards of the Genus Mabuya." In Reproductive Biology of South American Vertebrates, 150–64. New York, NY: Springer New York, 1992. http://dx.doi.org/10.1007/978-1-4612-2866-0_11.

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Bontems, Christian. "Localization of spermatozoa inside viviparous and oviparous females of Chrysomelinae." In Biology of Chrysomelidae, 299–316. Dordrecht: Springer Netherlands, 1988. http://dx.doi.org/10.1007/978-94-009-3105-3_18.

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Korsgaard, B., and R. E. Weber. "Maternal-Fetal Trophic and Respiratory Relationships in Viviparous Ectothermic Vertebrates." In Advances in Comparative and Environmental Physiology, 209–33. Berlin, Heidelberg: Springer Berlin Heidelberg, 1989. http://dx.doi.org/10.1007/978-3-642-74510-2_7.

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Baskaran, Xavier Ravi, Antony Varuvel Geo Vigila, Wenbo Liao, and Zhang Shouzhou. "Selective Chinese Viviparous Ferns, Their Bioactive Principles and Economical Values." In Medicinal Plants, 223–38. Boca Raton : Taylor & Francis, 2018. | “A CRC title, part of the Taylor & Francis imprint, a member of the Taylor & Francis Group, the academic division of T&F Informa plc.”: CRC Press, 2018. http://dx.doi.org/10.1201/9781351046510-11.

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Conference papers on the topic "Viviparous"

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Rahman, A. "The Characteristics of Kasiro Shale and Its Implication to Oil Shale Identification at The Batang Asai, Sarolangun, Jambi." In Indonesian Petroleum Association 44th Annual Convention and Exhibition. Indonesian Petroleum Association, 2021. http://dx.doi.org/10.29118/ipa21-sg-260.

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The necessity of oil and natural gas from fossil energy sources in Indonesia is increasing over time, whereas oil and gas reserves generated from conventional reservoirs are decreasing. To anticipate gas shortages, exploration of unconventional resources is needed. The main focus of the rock formation in this research is the Tertiary Miocene Kasiro Formation. This formation is dominated by Shale and Claystone. Shale characteristic from the megascopic aspect of Tertiary Miocene Kasiro Formation in the research area have fissile structure with soft to hard in hardness scale of shale. Shale characteristic from microscopic aspect based on petrography, SEM (Scanning Electron Magnetic) and XRD (X-Ray Diffraction) show illite as main clay mineral. Other clay minerals such as montmorilonite and kaolinite also can be found as well as some important mineral like quartz, chlorite, biotite, alunite and diaspore. Shale diagenesis rate of the Tertiary Miocene Kasiro Formation is defined based on the presence of some clay mineral like illite, kaolinite and montmorillonite. Based on the result of SEM and XRD analyses, the shale diagenesis in the research area can be classified as early mesodiagenesis. The diagenesis rate also can show that oil maturity in the Kasiro shale can be classified as immature to semi mature. Based on the shale characteristic, the Kasiro shale was deposited in a weak current mechanism and based on the presence of alginite, the shale was deposited within lacustrine environment. The lacustrine environment have a characteristic of low oxygen rate that can be seen with the presence of mollusk fossil such as viviparous that indicating a fresh water and weak current enviroment.
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Marushchak, Oleksii, Oksana Nekrasova, Volodymyr Tytar, Mihails Pupins, Andris Čeirāns, and Arturs Skute. "Distribution of Viviparous American Fish Species in Eastern Europe on the Example of Gambusia Holbrooki Girarg, 1859 and Poecilia Reticulata Peters, 1859 in the Context of Global Climate Change <sup>†</sup>." In 1st International Electronic Conference on Biological Diversity, Ecology and Evolution. Basel, Switzerland: MDPI, 2021. http://dx.doi.org/10.3390/bdee2021-09398.

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Reports on the topic "Viviparous"

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Морфометрический анализ раковин живородки речной Viviparus viviparus (Linne, 1758) водоемов Республики Марий Эл. LJournal, 2016. http://dx.doi.org/10.18411/e-2016-007.

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