Aestivation in Amphibians, Reptiles, and Lungfish

Glass, Mogens L.; Amin-Naves, Jalile; Silva, Glauber S. F. da

doi:10.1007/978-3-540-93985-6_8

Cited by 6 publications

(11 citation statements)

References 33 publications

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“…In the present study, V O 2 measurement was not performed, but during aerial hypoxia and at high temperature the increased O 2 demand is mostly provided by the lungs, which is reflected by the amplified increase of i E . The lung must play a predominant role in respiratory adjustments to temperature, since the gills are rudimentary (Johansen and Lenfant, 1967;Lenfant et al, 1970;Glass et al, 2009;Amin-Naves et al, 2004).…”

Section: Discussionmentioning

confidence: 97%

“…The temperature of the water may quickly oscillate within a range of 18-34 1C (Harder et al, 1999). Besides the temperature oscillations that animal face in nature, L. paradoxa inhabits shallow waters,which may evaporate during drought, which forces the animal to enter into estivation, a dormancy state during the dry season that may occur at a constant temperature (Abe, 1995;Glass et al, 1997Glass et al, , 2009Glass, 2008). The ability to estivate is crucial for survival during this period.…”

Section: Discussionmentioning

confidence: 98%

“…Both depend on pulmonary ventilation (V E ) for O 2 uptake (V O2 ) (Lenfant et al, 1970), whereas Neoceratodus (Australian) possess a single lung combined with gills that suffice to sustain total metabolism in normoxic water (Fritsche et al, 1993). Among several respiratory functions shared by tetrapods and lungfish, such as pulmonary diffusing capacity (Bassi et al, 2005;de Moraes et al, 2005), pulmonary surfactant (Orgeig and Daniels, 1995) and hyperpnoea after-hypercapnia response (Glass et al, 2009;Sanchez and Glass, 2001), it appears that both possess central CO 2 /pH chemoreceptors (Sanchez et al, 2001b;Amin-Naves et al, 2007a, b).…”

Section: Introductionmentioning

confidence: 98%

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Combined ventilatory responses to aerial hypoxia and temperature in the South American lungfish Lepidosiren paradoxa

Silva

Giusti

Branco

et al. 2011

Journal of Thermal Biology

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Section: Discussionmentioning

confidence: 97%

Section: Discussionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 98%

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Combined ventilatory responses to aerial hypoxia and temperature in the South American lungfish Lepidosiren paradoxa

Silva

Giusti

Branco

et al. 2011

Journal of Thermal Biology

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“…During the dry season, L. paradoxa can be confined to ponds with decreasing water levels within the Pantanal grassland and are forced to burrow into the mud. Natural aerial hypoxic conditions may be experienced seasonally while buried into the mud (da Silva et al, 2008;Glass, 2008;Glass et al, 2009;Sanchez, 1993) because water-logged soils show limited gas diffusion. Furthermore, from an evolutionary perspective, the combination of elevated temperature and reduced oxygen availability used in the present study, simulate the atmospheric conditions present during the Middle Devonian, the epoch when lungfish probably evolved air-breathing abilities (Clement and Long, 2010).…”

Section: Discussionmentioning

confidence: 99%

“…Lepidosiren paradoxa, in Brazil locally known as pirambóia, inhabits the tropical (Amazon) and subtropical (Mato Grosso state) regions of Brazil. Their natural habitat is dominated by shallow waters covered by vegetation and the water level is constantly changing throughout the year causing seasonal droughts (Glass et al, 2009). Other seasonal changes include variations of water pH ranging from 6.5 to 9.0 and water temperature that may oscillate from 18 to 34°C (Greenwood, 1986;Harder et al, 1999).…”

Section: Introductionmentioning

confidence: 99%

Effects of aerial hypoxia and temperature on pulmonary breathing pattern and gas exchange in the South American lungfish, Lepidosiren paradoxa

Silva

Ventura

Zena

et al. 2017

Comparative Biochemistry and Physiology Part A: Molecular &

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The South American lungfish Lepidosiren paradoxa is an obligatory air-breathing fish possessing well-developed bilateral lungs, and undergoing seasonal changes in its habitat, including temperature changes. In the present study we aimed to evaluate gas exchange and pulmonary breathing pattern in L. paradoxa at different temperatures (25 and 30°C) and different inspired O levels (21, 12, 10, and 7%). Normoxic breathing pattern consisted of isolated ventilatory cycles composed of an expiration followed by 2.4±0.2 buccal inspirations. Both expiratory and inspiratory tidal volumes reached a maximum of about 35mlkg, indicating that L. paradoxa is able to exchange nearly all of its lung air in a single ventilatory cycle. At both temperatures, hypoxia caused a significant increase in pulmonary ventilation (V̇), mainly due to an increase in respiratory frequency. Durations of the ventilatory cycle and expiratory and inspiratory tidal volumes were not significantly affected by hypoxia. Expiratory time (but not inspiratory) was significantly shorter at 30°C and at all O levels. While a small change in oxygen consumption (V̇O) could be noticed, the carbon dioxide release (V̇CO, P=0.0003) and air convection requirement (V̇/V̇O, P=0.0001) were significantly affected by hypoxia (7% O) at both temperatures, when compared to normoxia, and pulmonary diffusion capacity increased about four-fold due to hypoxic exposure. These data highlight important features of the respiratory system of L. paradoxa, capable of matching O demand and supply under different environmental change, as well as help to understand the evolution of air breathing in lungfish.

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How Aestivation Evolved in Turtles: A Macroevolutionary and Morphological Approach

2023

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Aestivation (summer dormancy) is a long-term multiday torpor in response to hot and dry periods. It has been detected in many species of terrestrial and aquatic turtles; however, several ecological and evolutionary aspects of chelonian aestivation remain to be evaluated and understood. We conducted a comparative exploration of macroevolutionary trends in turtle aestivation and tested the potential correlation of shell morphology with the aestivation duration. We compiled a dataset of aestivation status, aestivation times, and measurements of shell morphology of 225 turtle species. We reconstructed ancestral states along a time-calibrated phylogeny and tested different evolutionary models on the presence/absence of the aestivation trait. We also performed phylogenetic comparative analysis to explore several shell morphological traits likely associated with the duration time in aestivation behavior. We found evidence of aestivation in 44% of the evaluated turtle species. Aestivation times were longer in Chelidae, Pelomedusidae, Geoemydidae, and Kinosternidae, and the shortest times in Emydidae and Testudinidae. Aestivation behavior is a derived trait evolved independently and several times in the pleurodires and cryptodires turtle groups. We found some evolutionary trends in different turtle families, Pelomedusidae and Kinosternidae showed considerable increases in the presence of the aestivation trait, while families such as Podocnemididae, Trionychidae and Chelydridae showed important deductions for the same trait. Our results for the association between shell morphology and aestivation duration in turtles were contrasting among families. Overall, it was the contribution of several and different morphological traits that allow a positive and significant association with the aestivation times.

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Aestivation in Amphibians, Reptiles, and Lungfish

Cited by 6 publications

References 33 publications

Combined ventilatory responses to aerial hypoxia and temperature in the South American lungfish Lepidosiren paradoxa

Combined ventilatory responses to aerial hypoxia and temperature in the South American lungfish Lepidosiren paradoxa

Effects of aerial hypoxia and temperature on pulmonary breathing pattern and gas exchange in the South American lungfish, Lepidosiren paradoxa

How Aestivation Evolved in Turtles: A Macroevolutionary and Morphological Approach

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