Lizard Development - Revision history

Z8600021 at 02:07, 29 July 2019

2019-07-29T02:07:11Z

← Older revision		Revision as of 12:07, 29 July 2019
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	* '''Egg incubation temperature influences the growth and foraging behaviour of juvenile lizards'''{{#pmid:31170461\|PMID31170461}} "After laying their eggs, oviparous reptiles are reliant on the external environment to provide the required incubation conditions for successful embryonic development. Egg incubation temperature can impact the behaviour of various species of reptiles, but previous experiments have focused on the impact of incubation environment on hatchlings, with only a limited number of studies focussing on the longer-term behavioural consequences of incubation environment. This study investigated the effects of developmental environment on bearded dragon lizards (Pogona vitticeps) that were incubated at different temperatures within the natural range; half of them were incubated at a 'hot' temperature (30 ± 3 °C) and half at a 'cold' temperature (27 ± 3 °C). The growth and foraging behaviour of the lizards was then compared over 18 weeks of development. Although the lizards incubated at a cool temperatures grew more quickly, those incubated at the hotter temperature completed the foraging task more often and had significantly faster running speeds. These results show that egg incubation temperature impacts the foraging behaviour of juvenile lizards and suggest a potential trade-off between growth and foraging speed, which could influence an animal's life history trajectory." {{DOHAD}}		* '''Egg incubation temperature influences the growth and foraging behaviour of juvenile lizards'''{{#pmid:31170461\|PMID31170461}} "After laying their eggs, oviparous reptiles are reliant on the external environment to provide the required incubation conditions for successful embryonic development. Egg incubation temperature can impact the behaviour of various species of reptiles, but previous experiments have focused on the impact of incubation environment on hatchlings, with only a limited number of studies focussing on the longer-term behavioural consequences of incubation environment. This study investigated the effects of developmental environment on bearded dragon lizards (Pogona vitticeps) that were incubated at different temperatures within the natural range; half of them were incubated at a 'hot' temperature (30 ± 3 °C) and half at a 'cold' temperature (27 ± 3 °C). The growth and foraging behaviour of the lizards was then compared over 18 weeks of development. Although the lizards incubated at a cool temperatures grew more quickly, those incubated at the hotter temperature completed the foraging task more often and had significantly faster running speeds. These results show that egg incubation temperature impacts the foraging behaviour of juvenile lizards and suggest a potential trade-off between growth and foraging speed, which could influence an animal's life history trajectory." {{DOHAD}}

	* '''Skull Development, Ossification Pattern, and Adult Shape in the Emerging Lizard Model Organism Pogona vitticeps: A Comparative Analysis With Other Squamates'''{{#pmid:29643813\|PMID29643813}} "The rise of the Evo-Devo field and the development of multidisciplinary research tools at various levels of biological organization have led to a growing interest in researching for new non-model organisms. Squamates (lizards and snakes) are particularly important for understanding fundamental questions about the evolution of vertebrates because of their high diversity and evolutionary innovations and adaptations that portrait a striking body plan change that reached its extreme in snakes. Yet, little is known about the intricate connection between phenotype and genotype in squamates, partly due to limited developmental knowledge and incomplete characterization of embryonic development. Surprisingly, squamate models have received limited attention in comparative developmental studies, and only a few species examined so far can be considered as representative and appropriate model organism for mechanistic Evo-Devo studies. Fortunately, the agamid lizard Pogona vitticeps (central bearded dragon) is one of the most popular, domesticated reptile species with both a well-established history in captivity and key advantages for research, thus forming an ideal laboratory model system and justifying his recent use in reptile biology research. We first report here the complete post-oviposition embryonic development for P. vitticeps based on standardized staging systems and external morphological characters previously defined for squamates. Whereas the overall morphological development follows the general trends observed in other squamates, our comparisons indicate major differences in the developmental sequence of several tissues, including early craniofacial characters. Detailed analysis of both embryonic skull development and adult skull shape, using a comparative approach integrating CT-scans and gene expression studies in P. vitticeps as well as comparative embryology and 3D geometric morphometrics in a large dataset of lizards and snakes, highlights the extreme adult {{skull}} shape of P. vitticeps and further indicates that heterochrony has played a key role in the early development and ossification of squamate skull bones."		* '''{{Skull}} Development, Ossification Pattern, and Adult Shape in the Emerging Lizard Model Organism Pogona vitticeps: A Comparative Analysis With Other Squamates'''{{#pmid:29643813\|PMID29643813}} "The rise of the Evo-Devo field and the development of multidisciplinary research tools at various levels of biological organization have led to a growing interest in researching for new non-model organisms. Squamates (lizards and snakes) are particularly important for understanding fundamental questions about the evolution of vertebrates because of their high diversity and evolutionary innovations and adaptations that portrait a striking body plan change that reached its extreme in snakes. Yet, little is known about the intricate connection between phenotype and genotype in squamates, partly due to limited developmental knowledge and incomplete characterization of embryonic development. Surprisingly, squamate models have received limited attention in comparative developmental studies, and only a few species examined so far can be considered as representative and appropriate model organism for mechanistic Evo-Devo studies. Fortunately, the agamid lizard Pogona vitticeps (central bearded dragon) is one of the most popular, domesticated reptile species with both a well-established history in captivity and key advantages for research, thus forming an ideal laboratory model system and justifying his recent use in reptile biology research. We first report here the complete post-oviposition embryonic development for P. vitticeps based on standardized staging systems and external morphological characters previously defined for squamates. Whereas the overall morphological development follows the general trends observed in other squamates, our comparisons indicate major differences in the developmental sequence of several tissues, including early craniofacial characters. Detailed analysis of both embryonic skull development and adult skull shape, using a comparative approach integrating CT-scans and gene expression studies in P. vitticeps as well as comparative embryology and 3D geometric morphometrics in a large dataset of lizards and snakes, highlights the extreme adult {{skull}} shape of P. vitticeps and further indicates that heterochrony has played a key role in the early development and ossification of squamate skull bones."

	* '''{{Yolk sac}} development in lizards (Lacertilia: Scincidae): New perspectives on the egg of amniotes'''{{#pmid:28168721\|PMID28168721}} "Embryos of oviparous reptiles develop on the surface of a large mass of yolk, which they metabolize to become relatively large hatchlings. Access to the yolk is provided by tissues growing outward from the embryo to cover the surface of the yolk. A key feature of yolk sac development is a dedicated blood vascular system to communicate with the embryo. The best known model for yolk sac development and function of oviparous amniotes is based on numerous studies of birds, primarily domestic chickens. In this model, the vascular yolk sac forms the perimeter of the large yolk mass and is lined by a specialized epithelium, which takes up, processes and transports yolk nutrients to the yolk sac blood vessels. Studies of lizard yolk sac development, dating to more than 100 years ago, report characteristics inconsistent with this model. We compared development of the yolk sac from oviposition to near hatching in embryonic series of three species of oviparous scincid lizards to consider congruence with the pattern described for birds. Our findings reinforce results of prior studies indicating that squamate reptiles mobilize and metabolize the large yolk reserves in their eggs through a process unknown in other amniotes. Development of the yolk sac of lizards differs from birds in four primary characteristics, migration of mesoderm, proliferation of endoderm, vascular development and cellular diversity within the yolk sac cavity. Notably, all of the yolk is incorporated into cells relatively early in development and endodermal cells within the yolk sac cavity align along blood vessels which course throughout the yolk sac cavity. The pattern of uptake of yolk by endodermal cells indicates that the mechanism of yolk metabolism differs between lizards and birds and that the evolution of a fundamental characteristic of embryonic nutrition diverged in these two lineages. Attributes of the yolk sac of squamates reveal the existence of phylogenetic diversity among amniote lineages and raise new questions concerning the evolution of the amniotic egg."		* '''{{Yolk sac}} development in lizards (Lacertilia: Scincidae): New perspectives on the egg of amniotes'''{{#pmid:28168721\|PMID28168721}} "Embryos of oviparous reptiles develop on the surface of a large mass of yolk, which they metabolize to become relatively large hatchlings. Access to the yolk is provided by tissues growing outward from the embryo to cover the surface of the yolk. A key feature of yolk sac development is a dedicated blood vascular system to communicate with the embryo. The best known model for yolk sac development and function of oviparous amniotes is based on numerous studies of birds, primarily domestic chickens. In this model, the vascular yolk sac forms the perimeter of the large yolk mass and is lined by a specialized epithelium, which takes up, processes and transports yolk nutrients to the yolk sac blood vessels. Studies of lizard yolk sac development, dating to more than 100 years ago, report characteristics inconsistent with this model. We compared development of the yolk sac from oviposition to near hatching in embryonic series of three species of oviparous scincid lizards to consider congruence with the pattern described for birds. Our findings reinforce results of prior studies indicating that squamate reptiles mobilize and metabolize the large yolk reserves in their eggs through a process unknown in other amniotes. Development of the yolk sac of lizards differs from birds in four primary characteristics, migration of mesoderm, proliferation of endoderm, vascular development and cellular diversity within the yolk sac cavity. Notably, all of the yolk is incorporated into cells relatively early in development and endodermal cells within the yolk sac cavity align along blood vessels which course throughout the yolk sac cavity. The pattern of uptake of yolk by endodermal cells indicates that the mechanism of yolk metabolism differs between lizards and birds and that the evolution of a fundamental characteristic of embryonic nutrition diverged in these two lineages. Attributes of the yolk sac of squamates reveal the existence of phylogenetic diversity among amniote lineages and raise new questions concerning the evolution of the amniotic egg."

	* '''Identifying the evolutionary building blocks of the cardiac conduction system'''{{#pmid:22984480\|PMID22984480}} "The endothermic state of mammals and birds requires high {{heart}} rates to accommodate the high rates of oxygen consumption. These high heart rates are driven by very similar conduction systems consisting of an atrioventricular node that slows the electrical impulse and a His-Purkinje system that efficiently activates the ventricular chambers. While ectothermic vertebrates have similar contraction patterns, they do not possess anatomical evidence for a conduction system. ... Mammalian and avian ventricles uniquely develop thick compact walls and septum and, hence, form a discrete ventricular conduction system from the embryonic spongy ventricle. Our study uncovers the evolutionary building plan of heart and indicates that the building blocks of the conduction system of adult ectothermic vertebrates and embryos of endotherms are similar."
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			* '''Identifying the evolutionary building blocks of the cardiac conduction system'''{{#pmid:22984480\|PMID22984480}} "The endothermic state of mammals and birds requires high {{heart}} rates to accommodate the high rates of oxygen consumption. These high heart rates are driven by very similar conduction systems consisting of an atrioventricular node that slows the electrical impulse and a His-Purkinje system that efficiently activates the ventricular chambers. While ectothermic vertebrates have similar contraction patterns, they do not possess anatomical evidence for a conduction system. ... Mammalian and avian ventricles uniquely develop thick compact walls and septum and, hence, form a discrete ventricular conduction system from the embryonic spongy ventricle. Our study uncovers the evolutionary building plan of heart and indicates that the building blocks of the conduction system of adult ectothermic vertebrates and embryos of endotherms are similar."

	* '''{{Tooth}} development in a model reptile: functional and null generation teeth in the gecko Paroedura picta'''{{#pmid:22780101\|PMID22780101}} "This paper describes tooth development in a basal squamate, Paroedura picta. Due to its reproductive strategy, mode of development and position within the reptiles, this gecko represents an excellent model organism for the study of reptile development. ...We show evidence for a stratum intermedium layer in the enamel epithelium of functional teeth and show that the bicuspid shape of the teeth is created by asymmetrical deposition of enamel, and not by folding of the inner dental epithelium as observed in mammals."		* '''{{Tooth}} development in a model reptile: functional and null generation teeth in the gecko Paroedura picta'''{{#pmid:22780101\|PMID22780101}} "This paper describes tooth development in a basal squamate, Paroedura picta. Due to its reproductive strategy, mode of development and position within the reptiles, this gecko represents an excellent model organism for the study of reptile development. ...We show evidence for a stratum intermedium layer in the enamel epithelium of functional teeth and show that the bicuspid shape of the teeth is created by asymmetrical deposition of enamel, and not by folding of the inner dental epithelium as observed in mammals."

	* '''Patterns of interspecific variation in the heart rates of embryonic reptiles'''{{#pmid:22174948\|PMID22174948}} "New non-invasive technologies allow direct measurement of heart rates (and thus, developmental rates) of embryos. We applied these methods to a diverse array of oviparous reptiles (24 species of lizards, 18 snakes, 11 turtles, 1 crocodilian), to identify general influences on cardiac rates during embryogenesis. Heart rates increased with ambient temperature in all lineages, but (at the same temperature) were faster in lizards and turtles than in snakes and crocodilians. We analysed these data within a phylogenetic framework. Embryonic heart rates were faster in species with smaller adult sizes, smaller egg sizes, and shorter incubation periods."		* '''Patterns of interspecific variation in the {{heart}} rates of embryonic reptiles'''{{#pmid:22174948\|PMID22174948}} "New non-invasive technologies allow direct measurement of heart rates (and thus, developmental rates) of embryos. We applied these methods to a diverse array of oviparous reptiles (24 species of lizards, 18 snakes, 11 turtles, 1 crocodilian), to identify general influences on cardiac rates during embryogenesis. Heart rates increased with ambient temperature in all lineages, but (at the same temperature) were faster in lizards and turtles than in snakes and crocodilians. We analysed these data within a phylogenetic framework. Embryonic heart rates were faster in species with smaller adult sizes, smaller egg sizes, and shorter incubation periods."

	* '''Reptilian spermatogenesis: A histological and ultrastructural perspective'''{{#pmid:22319673\|PMID22319673}} "Until recently, the histology and ultrastructural events of spermatogenesis in reptiles were relatively unknown. Most of the available morphological information focuses on specific stages of spermatogenesis, spermiogenesis, and/or of the mature spermatozoa. No study to date has provided complete ultrastructural information on the early events of spermatogenesis, proliferation and meiosis in class Reptilia. Furthermore, no comprehensive data set exists that describes the ultrastructure of the entire ontogenic progression of germ cells through the phases of reptilian spermatogenesis (mitosis, meiosis and spermiogenesis)."		* '''Reptilian spermatogenesis: A histological and ultrastructural perspective'''{{#pmid:22319673\|PMID22319673}} "Until recently, the histology and ultrastructural events of spermatogenesis in reptiles were relatively unknown. Most of the available morphological information focuses on specific stages of spermatogenesis, spermiogenesis, and/or of the mature spermatozoa. No study to date has provided complete ultrastructural information on the early events of spermatogenesis, proliferation and meiosis in class Reptilia. Furthermore, no comprehensive data set exists that describes the ultrastructure of the entire ontogenic progression of germ cells through the phases of reptilian spermatogenesis (mitosis, meiosis and spermiogenesis)."

Z8600021 at 02:06, 29 July 2019

2019-07-29T02:06:15Z

← Older revision		Revision as of 12:06, 29 July 2019
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			* '''Egg incubation temperature influences the growth and foraging behaviour of juvenile lizards'''{{#pmid:31170461\|PMID31170461}} "After laying their eggs, oviparous reptiles are reliant on the external environment to provide the required incubation conditions for successful embryonic development. Egg incubation temperature can impact the behaviour of various species of reptiles, but previous experiments have focused on the impact of incubation environment on hatchlings, with only a limited number of studies focussing on the longer-term behavioural consequences of incubation environment. This study investigated the effects of developmental environment on bearded dragon lizards (Pogona vitticeps) that were incubated at different temperatures within the natural range; half of them were incubated at a 'hot' temperature (30 ± 3 °C) and half at a 'cold' temperature (27 ± 3 °C). The growth and foraging behaviour of the lizards was then compared over 18 weeks of development. Although the lizards incubated at a cool temperatures grew more quickly, those incubated at the hotter temperature completed the foraging task more often and had significantly faster running speeds. These results show that egg incubation temperature impacts the foraging behaviour of juvenile lizards and suggest a potential trade-off between growth and foraging speed, which could influence an animal's life history trajectory." {{DOHAD}}

	* '''Skull Development, Ossification Pattern, and Adult Shape in the Emerging Lizard Model Organism Pogona vitticeps: A Comparative Analysis With Other Squamates'''{{#pmid:29643813\|PMID29643813}} "The rise of the Evo-Devo field and the development of multidisciplinary research tools at various levels of biological organization have led to a growing interest in researching for new non-model organisms. Squamates (lizards and snakes) are particularly important for understanding fundamental questions about the evolution of vertebrates because of their high diversity and evolutionary innovations and adaptations that portrait a striking body plan change that reached its extreme in snakes. Yet, little is known about the intricate connection between phenotype and genotype in squamates, partly due to limited developmental knowledge and incomplete characterization of embryonic development. Surprisingly, squamate models have received limited attention in comparative developmental studies, and only a few species examined so far can be considered as representative and appropriate model organism for mechanistic Evo-Devo studies. Fortunately, the agamid lizard Pogona vitticeps (central bearded dragon) is one of the most popular, domesticated reptile species with both a well-established history in captivity and key advantages for research, thus forming an ideal laboratory model system and justifying his recent use in reptile biology research. We first report here the complete post-oviposition embryonic development for P. vitticeps based on standardized staging systems and external morphological characters previously defined for squamates. Whereas the overall morphological development follows the general trends observed in other squamates, our comparisons indicate major differences in the developmental sequence of several tissues, including early craniofacial characters. Detailed analysis of both embryonic skull development and adult skull shape, using a comparative approach integrating CT-scans and gene expression studies in P. vitticeps as well as comparative embryology and 3D geometric morphometrics in a large dataset of lizards and snakes, highlights the extreme adult {{skull}} shape of P. vitticeps and further indicates that heterochrony has played a key role in the early development and ossification of squamate skull bones."		* '''Skull Development, Ossification Pattern, and Adult Shape in the Emerging Lizard Model Organism Pogona vitticeps: A Comparative Analysis With Other Squamates'''{{#pmid:29643813\|PMID29643813}} "The rise of the Evo-Devo field and the development of multidisciplinary research tools at various levels of biological organization have led to a growing interest in researching for new non-model organisms. Squamates (lizards and snakes) are particularly important for understanding fundamental questions about the evolution of vertebrates because of their high diversity and evolutionary innovations and adaptations that portrait a striking body plan change that reached its extreme in snakes. Yet, little is known about the intricate connection between phenotype and genotype in squamates, partly due to limited developmental knowledge and incomplete characterization of embryonic development. Surprisingly, squamate models have received limited attention in comparative developmental studies, and only a few species examined so far can be considered as representative and appropriate model organism for mechanistic Evo-Devo studies. Fortunately, the agamid lizard Pogona vitticeps (central bearded dragon) is one of the most popular, domesticated reptile species with both a well-established history in captivity and key advantages for research, thus forming an ideal laboratory model system and justifying his recent use in reptile biology research. We first report here the complete post-oviposition embryonic development for P. vitticeps based on standardized staging systems and external morphological characters previously defined for squamates. Whereas the overall morphological development follows the general trends observed in other squamates, our comparisons indicate major differences in the developmental sequence of several tissues, including early craniofacial characters. Detailed analysis of both embryonic skull development and adult skull shape, using a comparative approach integrating CT-scans and gene expression studies in P. vitticeps as well as comparative embryology and 3D geometric morphometrics in a large dataset of lizards and snakes, highlights the extreme adult {{skull}} shape of P. vitticeps and further indicates that heterochrony has played a key role in the early development and ossification of squamate skull bones."

Z8600021 at 02:02, 29 July 2019

2019-07-29T02:02:35Z

← Older revision		Revision as of 12:02, 29 July 2019
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	* '''Skull Development, Ossification Pattern, and Adult Shape in the Emerging Lizard Model Organism Pogona vitticeps: A Comparative Analysis With Other Squamates'''{{#pmid:29643813\|PMID29643813}} "The rise of the Evo-Devo field and the development of multidisciplinary research tools at various levels of biological organization have led to a growing interest in researching for new non-model organisms. Squamates (lizards and snakes) are particularly important for understanding fundamental questions about the evolution of vertebrates because of their high diversity and evolutionary innovations and adaptations that portrait a striking body plan change that reached its extreme in snakes. Yet, little is known about the intricate connection between phenotype and genotype in squamates, partly due to limited developmental knowledge and incomplete characterization of embryonic development. Surprisingly, squamate models have received limited attention in comparative developmental studies, and only a few species examined so far can be considered as representative and appropriate model organism for mechanistic Evo-Devo studies. Fortunately, the agamid lizard Pogona vitticeps (central bearded dragon) is one of the most popular, domesticated reptile species with both a well-established history in captivity and key advantages for research, thus forming an ideal laboratory model system and justifying his recent use in reptile biology research. We first report here the complete post-oviposition embryonic development for P. vitticeps based on standardized staging systems and external morphological characters previously defined for squamates. Whereas the overall morphological development follows the general trends observed in other squamates, our comparisons indicate major differences in the developmental sequence of several tissues, including early craniofacial characters. Detailed analysis of both embryonic skull development and adult skull shape, using a comparative approach integrating CT-scans and gene expression studies in P. vitticeps as well as comparative embryology and 3D geometric morphometrics in a large dataset of lizards and snakes, highlights the extreme adult {{skull}} shape of P. vitticeps and further indicates that heterochrony has played a key role in the early development and ossification of squamate skull bones."		* '''Skull Development, Ossification Pattern, and Adult Shape in the Emerging Lizard Model Organism Pogona vitticeps: A Comparative Analysis With Other Squamates'''{{#pmid:29643813\|PMID29643813}} "The rise of the Evo-Devo field and the development of multidisciplinary research tools at various levels of biological organization have led to a growing interest in researching for new non-model organisms. Squamates (lizards and snakes) are particularly important for understanding fundamental questions about the evolution of vertebrates because of their high diversity and evolutionary innovations and adaptations that portrait a striking body plan change that reached its extreme in snakes. Yet, little is known about the intricate connection between phenotype and genotype in squamates, partly due to limited developmental knowledge and incomplete characterization of embryonic development. Surprisingly, squamate models have received limited attention in comparative developmental studies, and only a few species examined so far can be considered as representative and appropriate model organism for mechanistic Evo-Devo studies. Fortunately, the agamid lizard Pogona vitticeps (central bearded dragon) is one of the most popular, domesticated reptile species with both a well-established history in captivity and key advantages for research, thus forming an ideal laboratory model system and justifying his recent use in reptile biology research. We first report here the complete post-oviposition embryonic development for P. vitticeps based on standardized staging systems and external morphological characters previously defined for squamates. Whereas the overall morphological development follows the general trends observed in other squamates, our comparisons indicate major differences in the developmental sequence of several tissues, including early craniofacial characters. Detailed analysis of both embryonic skull development and adult skull shape, using a comparative approach integrating CT-scans and gene expression studies in P. vitticeps as well as comparative embryology and 3D geometric morphometrics in a large dataset of lizards and snakes, highlights the extreme adult {{skull}} shape of P. vitticeps and further indicates that heterochrony has played a key role in the early development and ossification of squamate skull bones."

	* '''~~Identifying~~ the ~~evolutionary building blocks~~ of ~~the cardiac conduction system~~'''{{#pmid:~~22984480~~\|~~PMID22984480~~}} "~~The endothermic state~~ of ~~mammals and birds requires high heart rates to accommodate~~ the ~~high rates~~ of ~~oxygen consumption~~. ~~These high heart rates are driven~~ by ~~very similar conduction systems consisting~~ of ~~an atrioventricular node that slows~~ the ~~electrical impulse and~~ a ~~His-Purkinje~~ system ~~that efficiently activates~~ the ~~ventricular chambers~~. ~~While ectothermic vertebrates have similar contraction patterns~~, ~~they do not possess anatomical evidence for a conduction system~~. ~~... Mammalian~~ and ~~avian ventricles uniquely develop thick compact walls and septum~~ and, ~~hence~~, ~~form a discrete ventricular conduction system~~ from the ~~embryonic spongy ventricle~~. Our ~~study uncovers~~ the ~~evolutionary building plan~~ of ~~heart~~ and indicates that the ~~building blocks~~ of the ~~conduction system~~ of ~~adult ectothermic vertebrates~~ and ~~embryos~~ of ~~endotherms are similar~~."		* '''{{Yolk sac}} development in lizards (Lacertilia: Scincidae): New perspectives on the egg of amniotes'''{{#pmid:28168721\|PMID28168721}} "Embryos of oviparous reptiles develop on the surface of a large mass of yolk, which they metabolize to become relatively large hatchlings. Access to the yolk is provided by tissues growing outward from the embryo to cover the surface of the yolk. A key feature of yolk sac development is a dedicated blood vascular system to communicate with the embryo. The best known model for yolk sac development and function of oviparous amniotes is based on numerous studies of birds, primarily domestic chickens. In this model, the vascular yolk sac forms the perimeter of the large yolk mass and is lined by a specialized epithelium, which takes up, processes and transports yolk nutrients to the yolk sac blood vessels. Studies of lizard yolk sac development, dating to more than 100 years ago, report characteristics inconsistent with this model. We compared development of the yolk sac from oviposition to near hatching in embryonic series of three species of oviparous scincid lizards to consider congruence with the pattern described for birds. Our findings reinforce results of prior studies indicating that squamate reptiles mobilize and metabolize the large yolk reserves in their eggs through a process unknown in other amniotes. Development of the yolk sac of lizards differs from birds in four primary characteristics, migration of mesoderm, proliferation of endoderm, vascular development and cellular diversity within the yolk sac cavity. Notably, all of the yolk is incorporated into cells relatively early in development and endodermal cells within the yolk sac cavity align along blood vessels which course throughout the yolk sac cavity. The pattern of uptake of yolk by endodermal cells indicates that the mechanism of yolk metabolism differs between lizards and birds and that the evolution of a fundamental characteristic of embryonic nutrition diverged in these two lineages. Attributes of the yolk sac of squamates reveal the existence of phylogenetic diversity among amniote lineages and raise new questions concerning the evolution of the amniotic egg."

	* '''~~Tooth development in a model reptile: functional and null generation teeth in~~ the ~~gecko Paroedura picta~~'''{{#pmid:~~22780101~~\|~~PMID22780101~~}} "~~This paper describes tooth development in a basal squamate, Paroedura picta~~. ~~Due to its reproductive strategy, mode~~ of ~~development~~ and ~~position within~~ the ~~reptiles~~, ~~this gecko represents an excellent model organism~~ for ~~the study of reptile development~~. ...~~We show evidence for~~ a ~~stratum intermedium layer in~~ the ~~enamel epithelium~~ of ~~functional teeth~~ and ~~show~~ that the ~~bicuspid shape~~ of the ~~teeth is created by asymmetrical deposition~~ of ~~enamel,~~ and ~~not by folding~~ of ~~the inner dental epithelium as observed in mammals~~."		* '''Identifying the evolutionary building blocks of the cardiac conduction system'''{{#pmid:22984480\|PMID22984480}} "The endothermic state of mammals and birds requires high {{heart}} rates to accommodate the high rates of oxygen consumption. These high heart rates are driven by very similar conduction systems consisting of an atrioventricular node that slows the electrical impulse and a His-Purkinje system that efficiently activates the ventricular chambers. While ectothermic vertebrates have similar contraction patterns, they do not possess anatomical evidence for a conduction system. ... Mammalian and avian ventricles uniquely develop thick compact walls and septum and, hence, form a discrete ventricular conduction system from the embryonic spongy ventricle. Our study uncovers the evolutionary building plan of heart and indicates that the building blocks of the conduction system of adult ectothermic vertebrates and embryos of endotherms are similar."
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	\| {{Older papers}}		\| {{Older papers}}
			* '''{{Tooth}} development in a model reptile: functional and null generation teeth in the gecko Paroedura picta'''{{#pmid:22780101\|PMID22780101}} "This paper describes tooth development in a basal squamate, Paroedura picta. Due to its reproductive strategy, mode of development and position within the reptiles, this gecko represents an excellent model organism for the study of reptile development. ...We show evidence for a stratum intermedium layer in the enamel epithelium of functional teeth and show that the bicuspid shape of the teeth is created by asymmetrical deposition of enamel, and not by folding of the inner dental epithelium as observed in mammals."

	* '''Patterns of interspecific variation in the heart rates of embryonic reptiles'''{{#pmid:22174948\|PMID22174948}} "New non-invasive technologies allow direct measurement of heart rates (and thus, developmental rates) of embryos. We applied these methods to a diverse array of oviparous reptiles (24 species of lizards, 18 snakes, 11 turtles, 1 crocodilian), to identify general influences on cardiac rates during embryogenesis. Heart rates increased with ambient temperature in all lineages, but (at the same temperature) were faster in lizards and turtles than in snakes and crocodilians. We analysed these data within a phylogenetic framework. Embryonic heart rates were faster in species with smaller adult sizes, smaller egg sizes, and shorter incubation periods."		* '''Patterns of interspecific variation in the heart rates of embryonic reptiles'''{{#pmid:22174948\|PMID22174948}} "New non-invasive technologies allow direct measurement of heart rates (and thus, developmental rates) of embryos. We applied these methods to a diverse array of oviparous reptiles (24 species of lizards, 18 snakes, 11 turtles, 1 crocodilian), to identify general influences on cardiac rates during embryogenesis. Heart rates increased with ambient temperature in all lineages, but (at the same temperature) were faster in lizards and turtles than in snakes and crocodilians. We analysed these data within a phylogenetic framework. Embryonic heart rates were faster in species with smaller adult sizes, smaller egg sizes, and shorter incubation periods."

Z8600021 at 12:04, 6 Ocak 2019

2019-01-06T12:04:45Z

← Older revision		Revision as of 22:04, 6 Ocak 2019
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	The genome of the lizard ''Anolis carolinensis'' (green anole) from southeastern United States has a karyotype of 18 chromosomes, comprising six pairs of large macrochromosomes and 12 pairs of small microchromosomes, and has recently been sequenced ~~<ref name=~~PMID21881562~~><pubmed>21881562</pubmed></ref>~~. Interestingly, almost all reptilian genomes also contain "microchromosomes", very small chromosomes less than 20 Mb in sequence size. (More? [[#Genome\|Genome]])		The genome of the lizard ''Anolis carolinensis'' (green anole) from southeastern United States has a karyotype of 18 chromosomes, comprising six pairs of large macrochromosomes and 12 pairs of small microchromosomes, and has recently been sequenced{{#pmid:21881562\|PMID21881562}}. Interestingly, almost all reptilian genomes also contain "microchromosomes", very small chromosomes less than 20 Mb in sequence size. (More? [[#Genome\|Genome]])

Z8600021 at 12:04, 6 Ocak 2019

2019-01-06T12:04:10Z

← Older revision		Revision as of 22:04, 6 Ocak 2019
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	{{Lizard links}}		{{Lizard links}}
			<br>
			{{Animals}}
	== Some Recent Findings ==		== Some Recent Findings ==
	{\|		{\|

Z8600021 at 12:03, 6 Ocak 2019

2019-01-06T12:03:02Z

← Older revision		Revision as of 22:03, 6 Ocak 2019
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	=== Articles===		=== Articles===
			{{#pmid:29801642}}

			{{#pmid:28891227}}

			{{#pmid:28809029}}

	{{#pmid:19645023}}		{{#pmid:19645023}}

Z8600021 at 12:01, 6 Ocak 2019

2019-01-06T12:01:19Z

← Older revision		Revision as of 22:01, 6 Ocak 2019
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			* '''Skull Development, Ossification Pattern, and Adult Shape in the Emerging Lizard Model Organism Pogona vitticeps: A Comparative Analysis With Other Squamates'''{{#pmid:29643813\|PMID29643813}} "The rise of the Evo-Devo field and the development of multidisciplinary research tools at various levels of biological organization have led to a growing interest in researching for new non-model organisms. Squamates (lizards and snakes) are particularly important for understanding fundamental questions about the evolution of vertebrates because of their high diversity and evolutionary innovations and adaptations that portrait a striking body plan change that reached its extreme in snakes. Yet, little is known about the intricate connection between phenotype and genotype in squamates, partly due to limited developmental knowledge and incomplete characterization of embryonic development. Surprisingly, squamate models have received limited attention in comparative developmental studies, and only a few species examined so far can be considered as representative and appropriate model organism for mechanistic Evo-Devo studies. Fortunately, the agamid lizard Pogona vitticeps (central bearded dragon) is one of the most popular, domesticated reptile species with both a well-established history in captivity and key advantages for research, thus forming an ideal laboratory model system and justifying his recent use in reptile biology research. We first report here the complete post-oviposition embryonic development for P. vitticeps based on standardized staging systems and external morphological characters previously defined for squamates. Whereas the overall morphological development follows the general trends observed in other squamates, our comparisons indicate major differences in the developmental sequence of several tissues, including early craniofacial characters. Detailed analysis of both embryonic skull development and adult skull shape, using a comparative approach integrating CT-scans and gene expression studies in P. vitticeps as well as comparative embryology and 3D geometric morphometrics in a large dataset of lizards and snakes, highlights the extreme adult {{skull}} shape of P. vitticeps and further indicates that heterochrony has played a key role in the early development and ossification of squamate skull bones."

	* '''Identifying the evolutionary building blocks of the cardiac conduction system'''{{#pmid:22984480\|PMID22984480}} "The endothermic state of mammals and birds requires high heart rates to accommodate the high rates of oxygen consumption. These high heart rates are driven by very similar conduction systems consisting of an atrioventricular node that slows the electrical impulse and a His-Purkinje system that efficiently activates the ventricular chambers. While ectothermic vertebrates have similar contraction patterns, they do not possess anatomical evidence for a conduction system. ... Mammalian and avian ventricles uniquely develop thick compact walls and septum and, hence, form a discrete ventricular conduction system from the embryonic spongy ventricle. Our study uncovers the evolutionary building plan of heart and indicates that the building blocks of the conduction system of adult ectothermic vertebrates and embryos of endotherms are similar."		* '''Identifying the evolutionary building blocks of the cardiac conduction system'''{{#pmid:22984480\|PMID22984480}} "The endothermic state of mammals and birds requires high heart rates to accommodate the high rates of oxygen consumption. These high heart rates are driven by very similar conduction systems consisting of an atrioventricular node that slows the electrical impulse and a His-Purkinje system that efficiently activates the ventricular chambers. While ectothermic vertebrates have similar contraction patterns, they do not possess anatomical evidence for a conduction system. ... Mammalian and avian ventricles uniquely develop thick compact walls and septum and, hence, form a discrete ventricular conduction system from the embryonic spongy ventricle. Our study uncovers the evolutionary building plan of heart and indicates that the building blocks of the conduction system of adult ectothermic vertebrates and embryos of endotherms are similar."

Z8600021 at 11:58, 6 Ocak 2019

2019-01-06T11:58:25Z

← Older revision		Revision as of 21:58, 6 Ocak 2019
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	* '''Tooth development in a model reptile: functional and null generation teeth in the gecko Paroedura picta'''{{#pmid:22780101\|PMID22780101}} "This paper describes tooth development in a basal squamate, Paroedura picta. Due to its reproductive strategy, mode of development and position within the reptiles, this gecko represents an excellent model organism for the study of reptile development. ...We show evidence for a stratum intermedium layer in the enamel epithelium of functional teeth and show that the bicuspid shape of the teeth is created by asymmetrical deposition of enamel, and not by folding of the inner dental epithelium as observed in mammals."		* '''Tooth development in a model reptile: functional and null generation teeth in the gecko Paroedura picta'''{{#pmid:22780101\|PMID22780101}} "This paper describes tooth development in a basal squamate, Paroedura picta. Due to its reproductive strategy, mode of development and position within the reptiles, this gecko represents an excellent model organism for the study of reptile development. ...We show evidence for a stratum intermedium layer in the enamel epithelium of functional teeth and show that the bicuspid shape of the teeth is created by asymmetrical deposition of enamel, and not by folding of the inner dental epithelium as observed in mammals."

	* '''Patterns of interspecific variation in the heart rates of embryonic reptiles'''{{#pmid:22174948\|PMID22174948}} "New non-invasive technologies allow direct measurement of heart rates (and thus, developmental rates) of embryos. We applied these methods to a diverse array of oviparous reptiles (24 species of lizards, 18 snakes, 11 turtles, 1 crocodilian), to identify general influences on cardiac rates during embryogenesis. Heart rates increased with ambient temperature in all lineages, but (at the same temperature) were faster in lizards and turtles than in snakes and crocodilians. We analysed these data within a phylogenetic framework. Embryonic heart rates were faster in species with smaller adult sizes, smaller egg sizes, and shorter incubation periods."

	* '''Reptilian spermatogenesis: A histological and ultrastructural perspective'''{{#pmid:22319673\|PMID22319673}} "Until recently, the histology and ultrastructural events of spermatogenesis in reptiles were relatively unknown. Most of the available morphological information focuses on specific stages of spermatogenesis, spermiogenesis, and/or of the mature spermatozoa. No study to date has provided complete ultrastructural information on the early events of spermatogenesis, proliferation and meiosis in class Reptilia. Furthermore, no comprehensive data set exists that describes the ultrastructure of the entire ontogenic progression of germ cells through the phases of reptilian spermatogenesis (mitosis, meiosis and spermiogenesis)."
	\|}		\|}
	{\| class="wikitable mw-collapsible mw-collapsed"		{\| class="wikitable mw-collapsible mw-collapsed"
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	\| [[File:Mark_Hill.jpg\|90px\|left]] {{Most_Recent_Refs}}		\| [[File:Mark_Hill.jpg\|90px\|left]] {{Most_Recent_Refs}}

	Search term: [http://www.ncbi.nlm.nih.gov/pubmed/?term=Lizard+Embryology ''Lizard Embryology'']		Search term: [http://www.ncbi.nlm.nih.gov/pubmed/?term=Lizard+Embryology ''Lizard Embryology''] \| [http://www.ncbi.nlm.nih.gov/pubmed/?term=Lizard+Development ''Lizard Development''] \| [http://www.ncbi.nlm.nih.gov/pubmed/?term=Reptile+Embryology ''Reptile Embryology'']

			\|}
			{\| class="wikitable mw-collapsible mw-collapsed"
			! Older papers
			\|-
			\| {{Older papers}}
			* '''Patterns of interspecific variation in the heart rates of embryonic reptiles'''{{#pmid:22174948\|PMID22174948}} "New non-invasive technologies allow direct measurement of heart rates (and thus, developmental rates) of embryos. We applied these methods to a diverse array of oviparous reptiles (24 species of lizards, 18 snakes, 11 turtles, 1 crocodilian), to identify general influences on cardiac rates during embryogenesis. Heart rates increased with ambient temperature in all lineages, but (at the same temperature) were faster in lizards and turtles than in snakes and crocodilians. We analysed these data within a phylogenetic framework. Embryonic heart rates were faster in species with smaller adult sizes, smaller egg sizes, and shorter incubation periods."

	~~<pubmed limit=5>Lizard Embryology<~~/~~pubmed>~~		* '''Reptilian spermatogenesis: A histological and ultrastructural perspective'''{{#pmid:22319673\|PMID22319673}} "Until recently, the histology and ultrastructural events of spermatogenesis in reptiles were relatively unknown. Most of the available morphological information focuses on specific stages of spermatogenesis, spermiogenesis, and/or of the mature spermatozoa. No study to date has provided complete ultrastructural information on the early events of spermatogenesis, proliferation and meiosis in class Reptilia. Furthermore, no comprehensive data set exists that describes the ultrastructure of the entire ontogenic progression of germ cells through the phases of reptilian spermatogenesis (mitosis, meiosis and spermiogenesis)."
	\|}		\|}
	== Taxon ==		== Taxon ==

Z8600021 at 07:27, 28 Haziran 2018

2018-06-28T07:27:37Z

← Older revision		Revision as of 17:27, 28 Haziran 2018
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	\|-bgcolor="F5FAFF"		\|-bgcolor="F5FAFF"
	\|		\|
	* '''Identifying the evolutionary building blocks of the cardiac conduction system'''{{#pmid:~~22984480PMID22984480~~}} "The endothermic state of mammals and birds requires high heart rates to accommodate the high rates of oxygen consumption. These high heart rates are driven by very similar conduction systems consisting of an atrioventricular node that slows the electrical impulse and a His-Purkinje system that efficiently activates the ventricular chambers. While ectothermic vertebrates have similar contraction patterns, they do not possess anatomical evidence for a conduction system. ... Mammalian and avian ventricles uniquely develop thick compact walls and septum and, hence, form a discrete ventricular conduction system from the embryonic spongy ventricle. Our study uncovers the evolutionary building plan of heart and indicates that the building blocks of the conduction system of adult ectothermic vertebrates and embryos of endotherms are similar."		* '''Identifying the evolutionary building blocks of the cardiac conduction system'''{{#pmid:22984480\|PMID22984480}} "The endothermic state of mammals and birds requires high heart rates to accommodate the high rates of oxygen consumption. These high heart rates are driven by very similar conduction systems consisting of an atrioventricular node that slows the electrical impulse and a His-Purkinje system that efficiently activates the ventricular chambers. While ectothermic vertebrates have similar contraction patterns, they do not possess anatomical evidence for a conduction system. ... Mammalian and avian ventricles uniquely develop thick compact walls and septum and, hence, form a discrete ventricular conduction system from the embryonic spongy ventricle. Our study uncovers the evolutionary building plan of heart and indicates that the building blocks of the conduction system of adult ectothermic vertebrates and embryos of endotherms are similar."

	* '''Tooth development in a model reptile: functional and null generation teeth in the gecko Paroedura picta'''{{#pmid:22780101\|PMID22780101}} "This paper describes tooth development in a basal squamate, Paroedura picta. Due to its reproductive strategy, mode of development and position within the reptiles, this gecko represents an excellent model organism for the study of reptile development. ...We show evidence for a stratum intermedium layer in the enamel epithelium of functional teeth and show that the bicuspid shape of the teeth is created by asymmetrical deposition of enamel, and not by folding of the inner dental epithelium as observed in mammals."		* '''Tooth development in a model reptile: functional and null generation teeth in the gecko Paroedura picta'''{{#pmid:22780101\|PMID22780101}} "This paper describes tooth development in a basal squamate, Paroedura picta. Due to its reproductive strategy, mode of development and position within the reptiles, this gecko represents an excellent model organism for the study of reptile development. ...We show evidence for a stratum intermedium layer in the enamel epithelium of functional teeth and show that the bicuspid shape of the teeth is created by asymmetrical deposition of enamel, and not by folding of the inner dental epithelium as observed in mammals."
Line 24:		Line 24:
	\|}		\|}
	{\| class="wikitable mw-collapsible mw-collapsed"		{\| class="wikitable mw-collapsible mw-collapsed"
	! More recent papers		! More recent papers
	\|-		\|-
	\| [[File:Mark_Hill.jpg\|90px\|left]] {{Most_Recent_Refs}}		\| [[File:Mark_Hill.jpg\|90px\|left]] {{Most_Recent_Refs}}

Z8600021 at 07:27, 28 Haziran 2018

2018-06-28T07:27:03Z

← Older revision		Revision as of 17:27, 28 Haziran 2018
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	{{Ref-Herrick1948}}		{{Ref-Herrick1948}}

			{{Herrick1948 TOC}}

	== External Links ==		== External Links ==

← Older revision		Revision as of 12:07, 29 July 2019
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	* '''Egg incubation temperature influences the growth and foraging behaviour of juvenile lizards'''{{#pmid:31170461\|PMID31170461}} "After laying their eggs, oviparous reptiles are reliant on the external environment to provide the required incubation conditions for successful embryonic development. Egg incubation temperature can impact the behaviour of various species of reptiles, but previous experiments have focused on the impact of incubation environment on hatchlings, with only a limited number of studies focussing on the longer-term behavioural consequences of incubation environment. This study investigated the effects of developmental environment on bearded dragon lizards (Pogona vitticeps) that were incubated at different temperatures within the natural range; half of them were incubated at a 'hot' temperature (30 ± 3 °C) and half at a 'cold' temperature (27 ± 3 °C). The growth and foraging behaviour of the lizards was then compared over 18 weeks of development. Although the lizards incubated at a cool temperatures grew more quickly, those incubated at the hotter temperature completed the foraging task more often and had significantly faster running speeds. These results show that egg incubation temperature impacts the foraging behaviour of juvenile lizards and suggest a potential trade-off between growth and foraging speed, which could influence an animal's life history trajectory." {{DOHAD}}		* '''Egg incubation temperature influences the growth and foraging behaviour of juvenile lizards'''{{#pmid:31170461\|PMID31170461}} "After laying their eggs, oviparous reptiles are reliant on the external environment to provide the required incubation conditions for successful embryonic development. Egg incubation temperature can impact the behaviour of various species of reptiles, but previous experiments have focused on the impact of incubation environment on hatchlings, with only a limited number of studies focussing on the longer-term behavioural consequences of incubation environment. This study investigated the effects of developmental environment on bearded dragon lizards (Pogona vitticeps) that were incubated at different temperatures within the natural range; half of them were incubated at a 'hot' temperature (30 ± 3 °C) and half at a 'cold' temperature (27 ± 3 °C). The growth and foraging behaviour of the lizards was then compared over 18 weeks of development. Although the lizards incubated at a cool temperatures grew more quickly, those incubated at the hotter temperature completed the foraging task more often and had significantly faster running speeds. These results show that egg incubation temperature impacts the foraging behaviour of juvenile lizards and suggest a potential trade-off between growth and foraging speed, which could influence an animal's life history trajectory." {{DOHAD}}

	* '''Skull Development, Ossification Pattern, and Adult Shape in the Emerging Lizard Model Organism Pogona vitticeps: A Comparative Analysis With Other Squamates'''{{#pmid:29643813\|PMID29643813}} "The rise of the Evo-Devo field and the development of multidisciplinary research tools at various levels of biological organization have led to a growing interest in researching for new non-model organisms. Squamates (lizards and snakes) are particularly important for understanding fundamental questions about the evolution of vertebrates because of their high diversity and evolutionary innovations and adaptations that portrait a striking body plan change that reached its extreme in snakes. Yet, little is known about the intricate connection between phenotype and genotype in squamates, partly due to limited developmental knowledge and incomplete characterization of embryonic development. Surprisingly, squamate models have received limited attention in comparative developmental studies, and only a few species examined so far can be considered as representative and appropriate model organism for mechanistic Evo-Devo studies. Fortunately, the agamid lizard Pogona vitticeps (central bearded dragon) is one of the most popular, domesticated reptile species with both a well-established history in captivity and key advantages for research, thus forming an ideal laboratory model system and justifying his recent use in reptile biology research. We first report here the complete post-oviposition embryonic development for P. vitticeps based on standardized staging systems and external morphological characters previously defined for squamates. Whereas the overall morphological development follows the general trends observed in other squamates, our comparisons indicate major differences in the developmental sequence of several tissues, including early craniofacial characters. Detailed analysis of both embryonic skull development and adult skull shape, using a comparative approach integrating CT-scans and gene expression studies in P. vitticeps as well as comparative embryology and 3D geometric morphometrics in a large dataset of lizards and snakes, highlights the extreme adult {{skull}} shape of P. vitticeps and further indicates that heterochrony has played a key role in the early development and ossification of squamate skull bones."		* '''{{Skull}} Development, Ossification Pattern, and Adult Shape in the Emerging Lizard Model Organism Pogona vitticeps: A Comparative Analysis With Other Squamates'''{{#pmid:29643813\|PMID29643813}} "The rise of the Evo-Devo field and the development of multidisciplinary research tools at various levels of biological organization have led to a growing interest in researching for new non-model organisms. Squamates (lizards and snakes) are particularly important for understanding fundamental questions about the evolution of vertebrates because of their high diversity and evolutionary innovations and adaptations that portrait a striking body plan change that reached its extreme in snakes. Yet, little is known about the intricate connection between phenotype and genotype in squamates, partly due to limited developmental knowledge and incomplete characterization of embryonic development. Surprisingly, squamate models have received limited attention in comparative developmental studies, and only a few species examined so far can be considered as representative and appropriate model organism for mechanistic Evo-Devo studies. Fortunately, the agamid lizard Pogona vitticeps (central bearded dragon) is one of the most popular, domesticated reptile species with both a well-established history in captivity and key advantages for research, thus forming an ideal laboratory model system and justifying his recent use in reptile biology research. We first report here the complete post-oviposition embryonic development for P. vitticeps based on standardized staging systems and external morphological characters previously defined for squamates. Whereas the overall morphological development follows the general trends observed in other squamates, our comparisons indicate major differences in the developmental sequence of several tissues, including early craniofacial characters. Detailed analysis of both embryonic skull development and adult skull shape, using a comparative approach integrating CT-scans and gene expression studies in P. vitticeps as well as comparative embryology and 3D geometric morphometrics in a large dataset of lizards and snakes, highlights the extreme adult {{skull}} shape of P. vitticeps and further indicates that heterochrony has played a key role in the early development and ossification of squamate skull bones."

	* '''{{Yolk sac}} development in lizards (Lacertilia: Scincidae): New perspectives on the egg of amniotes'''{{#pmid:28168721\|PMID28168721}} "Embryos of oviparous reptiles develop on the surface of a large mass of yolk, which they metabolize to become relatively large hatchlings. Access to the yolk is provided by tissues growing outward from the embryo to cover the surface of the yolk. A key feature of yolk sac development is a dedicated blood vascular system to communicate with the embryo. The best known model for yolk sac development and function of oviparous amniotes is based on numerous studies of birds, primarily domestic chickens. In this model, the vascular yolk sac forms the perimeter of the large yolk mass and is lined by a specialized epithelium, which takes up, processes and transports yolk nutrients to the yolk sac blood vessels. Studies of lizard yolk sac development, dating to more than 100 years ago, report characteristics inconsistent with this model. We compared development of the yolk sac from oviposition to near hatching in embryonic series of three species of oviparous scincid lizards to consider congruence with the pattern described for birds. Our findings reinforce results of prior studies indicating that squamate reptiles mobilize and metabolize the large yolk reserves in their eggs through a process unknown in other amniotes. Development of the yolk sac of lizards differs from birds in four primary characteristics, migration of mesoderm, proliferation of endoderm, vascular development and cellular diversity within the yolk sac cavity. Notably, all of the yolk is incorporated into cells relatively early in development and endodermal cells within the yolk sac cavity align along blood vessels which course throughout the yolk sac cavity. The pattern of uptake of yolk by endodermal cells indicates that the mechanism of yolk metabolism differs between lizards and birds and that the evolution of a fundamental characteristic of embryonic nutrition diverged in these two lineages. Attributes of the yolk sac of squamates reveal the existence of phylogenetic diversity among amniote lineages and raise new questions concerning the evolution of the amniotic egg."		* '''{{Yolk sac}} development in lizards (Lacertilia: Scincidae): New perspectives on the egg of amniotes'''{{#pmid:28168721\|PMID28168721}} "Embryos of oviparous reptiles develop on the surface of a large mass of yolk, which they metabolize to become relatively large hatchlings. Access to the yolk is provided by tissues growing outward from the embryo to cover the surface of the yolk. A key feature of yolk sac development is a dedicated blood vascular system to communicate with the embryo. The best known model for yolk sac development and function of oviparous amniotes is based on numerous studies of birds, primarily domestic chickens. In this model, the vascular yolk sac forms the perimeter of the large yolk mass and is lined by a specialized epithelium, which takes up, processes and transports yolk nutrients to the yolk sac blood vessels. Studies of lizard yolk sac development, dating to more than 100 years ago, report characteristics inconsistent with this model. We compared development of the yolk sac from oviposition to near hatching in embryonic series of three species of oviparous scincid lizards to consider congruence with the pattern described for birds. Our findings reinforce results of prior studies indicating that squamate reptiles mobilize and metabolize the large yolk reserves in their eggs through a process unknown in other amniotes. Development of the yolk sac of lizards differs from birds in four primary characteristics, migration of mesoderm, proliferation of endoderm, vascular development and cellular diversity within the yolk sac cavity. Notably, all of the yolk is incorporated into cells relatively early in development and endodermal cells within the yolk sac cavity align along blood vessels which course throughout the yolk sac cavity. The pattern of uptake of yolk by endodermal cells indicates that the mechanism of yolk metabolism differs between lizards and birds and that the evolution of a fundamental characteristic of embryonic nutrition diverged in these two lineages. Attributes of the yolk sac of squamates reveal the existence of phylogenetic diversity among amniote lineages and raise new questions concerning the evolution of the amniotic egg."

	* '''Identifying the evolutionary building blocks of the cardiac conduction system'''{{#pmid:22984480\|PMID22984480}} "The endothermic state of mammals and birds requires high {{heart}} rates to accommodate the high rates of oxygen consumption. These high heart rates are driven by very similar conduction systems consisting of an atrioventricular node that slows the electrical impulse and a His-Purkinje system that efficiently activates the ventricular chambers. While ectothermic vertebrates have similar contraction patterns, they do not possess anatomical evidence for a conduction system. ... Mammalian and avian ventricles uniquely develop thick compact walls and septum and, hence, form a discrete ventricular conduction system from the embryonic spongy ventricle. Our study uncovers the evolutionary building plan of heart and indicates that the building blocks of the conduction system of adult ectothermic vertebrates and embryos of endotherms are similar."
	\|}		\|}
	{\| class="wikitable mw-collapsible mw-collapsed"		{\| class="wikitable mw-collapsible mw-collapsed"
Line 36:		Line 34:
	\|-		\|-
	\| {{Older papers}}		\| {{Older papers}}
			* '''Identifying the evolutionary building blocks of the cardiac conduction system'''{{#pmid:22984480\|PMID22984480}} "The endothermic state of mammals and birds requires high {{heart}} rates to accommodate the high rates of oxygen consumption. These high heart rates are driven by very similar conduction systems consisting of an atrioventricular node that slows the electrical impulse and a His-Purkinje system that efficiently activates the ventricular chambers. While ectothermic vertebrates have similar contraction patterns, they do not possess anatomical evidence for a conduction system. ... Mammalian and avian ventricles uniquely develop thick compact walls and septum and, hence, form a discrete ventricular conduction system from the embryonic spongy ventricle. Our study uncovers the evolutionary building plan of heart and indicates that the building blocks of the conduction system of adult ectothermic vertebrates and embryos of endotherms are similar."

	* '''{{Tooth}} development in a model reptile: functional and null generation teeth in the gecko Paroedura picta'''{{#pmid:22780101\|PMID22780101}} "This paper describes tooth development in a basal squamate, Paroedura picta. Due to its reproductive strategy, mode of development and position within the reptiles, this gecko represents an excellent model organism for the study of reptile development. ...We show evidence for a stratum intermedium layer in the enamel epithelium of functional teeth and show that the bicuspid shape of the teeth is created by asymmetrical deposition of enamel, and not by folding of the inner dental epithelium as observed in mammals."		* '''{{Tooth}} development in a model reptile: functional and null generation teeth in the gecko Paroedura picta'''{{#pmid:22780101\|PMID22780101}} "This paper describes tooth development in a basal squamate, Paroedura picta. Due to its reproductive strategy, mode of development and position within the reptiles, this gecko represents an excellent model organism for the study of reptile development. ...We show evidence for a stratum intermedium layer in the enamel epithelium of functional teeth and show that the bicuspid shape of the teeth is created by asymmetrical deposition of enamel, and not by folding of the inner dental epithelium as observed in mammals."

	* '''Patterns of interspecific variation in the heart rates of embryonic reptiles'''{{#pmid:22174948\|PMID22174948}} "New non-invasive technologies allow direct measurement of heart rates (and thus, developmental rates) of embryos. We applied these methods to a diverse array of oviparous reptiles (24 species of lizards, 18 snakes, 11 turtles, 1 crocodilian), to identify general influences on cardiac rates during embryogenesis. Heart rates increased with ambient temperature in all lineages, but (at the same temperature) were faster in lizards and turtles than in snakes and crocodilians. We analysed these data within a phylogenetic framework. Embryonic heart rates were faster in species with smaller adult sizes, smaller egg sizes, and shorter incubation periods."		* '''Patterns of interspecific variation in the {{heart}} rates of embryonic reptiles'''{{#pmid:22174948\|PMID22174948}} "New non-invasive technologies allow direct measurement of heart rates (and thus, developmental rates) of embryos. We applied these methods to a diverse array of oviparous reptiles (24 species of lizards, 18 snakes, 11 turtles, 1 crocodilian), to identify general influences on cardiac rates during embryogenesis. Heart rates increased with ambient temperature in all lineages, but (at the same temperature) were faster in lizards and turtles than in snakes and crocodilians. We analysed these data within a phylogenetic framework. Embryonic heart rates were faster in species with smaller adult sizes, smaller egg sizes, and shorter incubation periods."

	* '''Reptilian spermatogenesis: A histological and ultrastructural perspective'''{{#pmid:22319673\|PMID22319673}} "Until recently, the histology and ultrastructural events of spermatogenesis in reptiles were relatively unknown. Most of the available morphological information focuses on specific stages of spermatogenesis, spermiogenesis, and/or of the mature spermatozoa. No study to date has provided complete ultrastructural information on the early events of spermatogenesis, proliferation and meiosis in class Reptilia. Furthermore, no comprehensive data set exists that describes the ultrastructure of the entire ontogenic progression of germ cells through the phases of reptilian spermatogenesis (mitosis, meiosis and spermiogenesis)."		* '''Reptilian spermatogenesis: A histological and ultrastructural perspective'''{{#pmid:22319673\|PMID22319673}} "Until recently, the histology and ultrastructural events of spermatogenesis in reptiles were relatively unknown. Most of the available morphological information focuses on specific stages of spermatogenesis, spermiogenesis, and/or of the mature spermatozoa. No study to date has provided complete ultrastructural information on the early events of spermatogenesis, proliferation and meiosis in class Reptilia. Furthermore, no comprehensive data set exists that describes the ultrastructure of the entire ontogenic progression of germ cells through the phases of reptilian spermatogenesis (mitosis, meiosis and spermiogenesis)."