Nocturnality in synapsids predates the origin of mammals by over 100 million years

Angielczyk, Kenneth D.; Schmitz, Lars

doi:10.1098/rspb.2014.1642

Cited by 80 publications

(85 citation statements)

References 63 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Larger sockets strongly correlate with larger eyes as shown by data on fish (SI Appendix, Estimating Eye and Pupil Size in Early Tetrapods and Fig. S4), reptiles (15), birds (16), and primates (17). Evidence spanning such a broad bracket of vertebrates shows that eye socket size in our group of ancient animals reliably captures what their eye size would have been.…”

Section: Computational Visual Ecologymentioning

confidence: 75%

Massive increase in visual range preceded the origin of terrestrial vertebrates

MacIver

Schmitz

Mugan

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

The evolution of terrestrial vertebrates, starting around 385 million years ago, is an iconic moment in evolution that brings to mind images of fish transforming into four-legged animals. Here, we show that this radical change in body shape was preceded by an equally dramatic change in sensory abilities akin to transitioning from seeing over short distances in a dense fog to seeing over long distances on a clear day. Measurements of eye sockets and simulations of their evolution show that eyes nearly tripled in size just before vertebrates began living on land. Computational simulations of these animal's visual ecology show that for viewing objects through water, the increase in eye size provided a negligible increase in performance. However, when viewing objects through air, the increase in eye size provided a large increase in performance. The jump in eye size was, therefore, unlikely to have arisen for seeing through water and instead points to an unexpected hybrid of seeing through air while still primarily inhabiting water. Our results and several anatomical innovations arising at the same time suggest lifestyle similarity to crocodiles. The consequent combination of the increase in eye size and vision through air would have conferred a 1 million-fold increase in the amount of space within which objects could be seen. The "buena vista" hypothesis that our data suggest is that seeing opportunities from afar played a role in the subsequent evolution of fully terrestrial limbs as well as the emergence of elaborated action sequences through planning circuits in the nervous system. fish-tetrapod transition | vision | visual ecology | terrestriality | prospective cognition B efore terrestrial vertebrates arose, their ancestors inhabited underwater environments, where vision is highly compromised compared with vision above water. The visual difference between life in water and life above it is comparable with driving fast on a foggy road, where our responses must be rapid and simple, vs. driving in clear daylight conditions, where deliberation over more complex choices is enabled by the vast increase in sensory range. Nonetheless, although an immense quantity of work has been done on the emergence of limbs during the evolution of land vertebrates, how visual capability changed during the transition from water to land has not been explored. In part, this lack of exploration is because computational visual ecology-necessary to interpret the fossil data-has not been combined with early tetrapod paleontology. Through combining these disciplines, here we probe the evolutionary history of the switch in our visual sensory ecology from water to air. Surprisingly, our results show that eyes tripled in size just before full-time life on land evolved. Convergent lines of evidence, including our own, strongly support the hypothesis that a crocodilian ecotype-using the greatly enhanced visual capabilities conferred by vision through air to prey on the bounty of unexploited invertebrates that long preceded the vertebrates onto ...

show abstract

Section: Computational Visual Ecologymentioning

confidence: 75%

Massive increase in visual range preceded the origin of terrestrial vertebrates

MacIver

Schmitz

Mugan

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

show abstract

“…The relative size of the scleral ring in the eye is often used as a proxy for the activity patterns of archosaurs, dinosaurs and therapsids (Schmitz & Motani, 2011;Angielczyk & Schmitz, 2014). Modern birds retain the scleral ring, whereas modern mammals do not.…”

Section: (5) Nocturnalismmentioning

confidence: 99%

“…Modern birds retain the scleral ring, whereas modern mammals do not. The relative size of the scleral ring is correlated with activity in extant birds and lizards; nocturnal birds have larger rings than crepuscular or diurnal birds (Schmitz & Motani, 2011;Angielczyk & Schmitz, 2014).…”

Section: (5) Nocturnalismmentioning

confidence: 99%

A phenology of the evolution of endothermy in birds and mammals

2016

View full text Add to dashboard Cite

Recent palaeontological data and novel physiological hypotheses now allow a timescaled reconstruction of the evolution of endothermy in birds and mammals. A three-phase iterative model describing how endothermy evolved from Permian ectothermic ancestors is presented. In Phase One I propose that the elevation of endothermy - increased metabolism and body temperature (T ) - complemented large-body-size homeothermy during the Permian and Triassic in response to the fitness benefits of enhanced embryo development (parental care) and the activity demands of conquering dry land. I propose that Phase Two commenced in the Late Triassic and Jurassic and was marked by extreme body-size miniaturization, the evolution of enhanced body insulation (fur and feathers), increased brain size, thermoregulatory control, and increased ecomorphological diversity. I suggest that Phase Three occurred during the Cretaceous and Cenozoic and involved endothermic pulses associated with the evolution of muscle-powered flapping flight in birds, terrestrial cursoriality in mammals, and climate adaptation in response to Late Cenozoic cooling in both birds and mammals. Although the triphasic model argues for an iterative evolution of endothermy in pulses throughout the Mesozoic and Cenozoic, it is also argued that endothermy was potentially abandoned at any time that a bird or mammal did not rely upon its thermal benefits for parental care or breeding success. The abandonment would have taken the form of either hibernation or daily torpor as observed in extant endotherms. Thus torpor and hibernation are argued to be as ancient as the origins of endothermy itself, a plesiomorphic characteristic observed today in many small birds and mammals.

show abstract

“…[27,[65][66][67][68]). Comparative studies have discussed transitions between nocturnality and diurnality, and have suggested that mammals have undergone a 'nocturnal bottleneck' during evolution to escape predation [69,70]. Macro-ecologists have recently identified large-scale patterns in daily timing of mammals across the globe [68,71].…”

Section: (B) Ecologymentioning

confidence: 99%

Two sides of a coin: ecological and chronobiological perspectives of timing in the wild

Helm

Visser

Schwartz

et al. 2017

Phil. Trans. R. Soc. B

132

189

View full text Add to dashboard Cite

Most processes within organisms, and most interactions between organisms and their environment, have distinct time profiles. The temporal coordination of such processes is crucial across levels of biological organization, but disciplines differ widely in their approaches to study timing. Such differences are accentuated between ecologists, who are centrally concerned with a holistic view of an organism in relation to its external environment, and chronobiologists, who emphasize internal timekeeping within an organism and the mechanisms of its adjustment to the environment. We argue that ecological and chronobiological perspectives are complementary, and that studies at the intersection will enable both fields to jointly overcome obstacles that currently hinder progress. However, to achieve this integration, we first have to cross some conceptual barriers, clarifying prohibitively inaccessible terminologies. We critically assess main assumptions and concepts in either field, as well as their common interests. Both approaches intersect in their need to understand the extent and regulation of temporal plasticity, and in the concept of 'chronotype', i.e. the characteristic temporal properties of individuals which are the targets of natural and sexual selection. We then highlight promising developments, point out open questions, acknowledge difficulties and propose directions for further integration of ecological and chronobiological perspectives through Wild Clock research.

show abstract

Nocturnality in synapsids predates the origin of mammals by over 100 million years

Cited by 80 publications

References 63 publications

Massive increase in visual range preceded the origin of terrestrial vertebrates

Massive increase in visual range preceded the origin of terrestrial vertebrates

A phenology of the evolution of endothermy in birds and mammals

Two sides of a coin: ecological and chronobiological perspectives of timing in the wild

Contact Info

Product

Resources

About