Daily Activity of Neotropical Dipsadid Snakes

Torello-Viera, Natália F.; Marques, Otávio A. V.

doi:10.2994/sajh-d-16-00023.1

Cited by 10 publications

(9 citation statements)

References 35 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“… Activity pattern and species habitat were stablished based on [ 12 , 13 ] D primarily diurnal, N primarily nocturnal, Aq aquatic, Ar arboreal, Fs fossorial, Te terrestrial …”

Section: Methodsmentioning

confidence: 99%

Daily activity patterns influence retinal morphology, signatures of selection, and spectral tuning of opsin genes in colubrid snakes

et al. 2017

View full text Add to dashboard Cite

BackgroundMorphological divergences of snake retinal structure point to complex evolutionary processes and adaptations. The Colubridae family has a remarkable variety of retinal structure that can range from all-cone and all-rod to duplex (cone/rod) retinas. To explore whether nocturnal versus diurnal activity is responsible for constraints on molecular evolution and plays a role in visual opsin spectral tuning of colubrids, we carried out molecular evolution analyses of the visual opsin genes LWS, RH1, and SWS1 from 17 species and performed morphological analyses.ResultsPhylogenetic reconstructions of the RH1 and LWS recovered major clades characterized by primarily diurnal or primarily nocturnal activity patterns, in contrast with the topology for SWS1, which is very similar to the species tree. We found stronger signals of purifying selection along diurnal and nocturnal lineages for RH1 and SWS1, respectively. A blue-shift of the RH1 spectral peak is associated with diurnal habits. Spectral tuning of cone opsins did not differ among diurnal and nocturnal species. Retinas of nocturnal colubrids had many rows of photoreceptor nuclei, with large numbers of rods, labeled by wheat germ agglutinin (WGA), and two types of cones: large cones sensitive to long/medium wavelengths (L/M) and small cones sensitive to ultra-violet/violet wavelengths (UV/VS). In contrast, retinas of diurnal species had only one row of photoreceptor nuclei, with four types of cones: large and double L/M cones, small UV/VS cones, and a second group of small cones, labeled by WGA.ConclusionsFor LWS gene, selection tests did not confirm different constraints related to activity pattern. For SWS1, stronger purifying selection in nocturnal lineages indicates divergent evolutionary pressures related to the activity pattern, and the importance of the short wavelength sensitivity at low light condition. Activity pattern has a clear influence on the signatures of selection and spectral tuning of RH1, with stronger purifying selection in diurnal lineages, which indicates selective pressure to preserve rhodopsin structure and function in pure-cone retinas. We suggest that the presence of four cone types in primarily diurnal colubrids might be related to the gain of color discrimination capacity.Electronic supplementary materialThe online version of this article (10.1186/s12862-017-1110-0) contains supplementary material, which is available to authorized users.

show abstract

“… Activity pattern and species habitat were stablished based on [ 12 , 13 ] D primarily diurnal, N primarily nocturnal, Aq aquatic, Ar arboreal, Fs fossorial, Te terrestrial …”

Section: Methodsmentioning

confidence: 99%

Daily activity patterns influence retinal morphology, signatures of selection, and spectral tuning of opsin genes in colubrid snakes

et al. 2017

View full text Add to dashboard Cite

show abstract

“…The animal procedures were done in accordance with the ethical principles of animal management and experimentation established by the Brazilian Animal Experiment College (COBEA). Species daily activity pattern and ecological features were established based on [77][78][79] ( Table 1).…”

Section: Assessing Cell Density and Topographic Distribution Across Tmentioning

confidence: 99%

“…, primarily diurnal; N, primarily nocturnal; an, anurans; ma, mammals; av., birds; ol, annelids; mo, mollusks; sn, snakes; fi, fish; li, lizards; HS, horizontal streak; AC, area centralis. Ecological features (biome, habitat, substrate, activity patter and diet) were stablished based on[77][78][79].…”

mentioning

confidence: 99%

Retinal Topographic Maps: A Glimpse into the Animals’ Visual World

Hauzman¹,

Bonci²,

Ventura³

2018

Sensory Nervous System

View full text Add to dashboard Cite

The vertebrates' retina has a highly conserved laminar organization of 10 alternating nuclear and plexiform layers. Species differences in the retinal specializations, i.e., areas of higher cell density, among the species, represent specific regions of the visual field of higher importance for a better spatial resolution and indicate distinct evolutionary pressures on the structures of the visual system, which can be related to many aspects of the species evolutionary history. In this chapter, we analyzed the density and distribution of cells of the retinal ganglion cell layer (GCL) and estimated the upper limits of the spatial resolving power of 12 species of snakes from the Colubridae family, 6 diurnal and 6 nocturnal, which inhabit different habitats. Our results revealed lower visual acuity in nocturnal species, compared to diurnal, and we observed different types of retinal specialization, horizontal streak, area centralis, or scattered distribution, with higher cell density in different retinal regions, depending on the species. These variations may be related to ecological and behavioral features, such as daily activity pattern, habitat, and substrate preferentially occupied, hunting strategies and diet. This comparative study indicates the complexity of the adaptive strategies of the snakes' visual system.

show abstract

“…2Tree topology used in codon-based likelihood models (random-site, branch-site and CmC models). Nocturnal species are represented by blue lines [56, 57, 62]. Hen, Henophidia; Cae, Caenophidia, V, Viperidae, E, Elapidae, C, colubridae…”

Section: Resultsmentioning

confidence: 99%

“…The suborder Serpentes comprises a highly diversified group of vertebrates and represents a valuable model to investigate specific functions and expression patterns of photosensitive proteins, which may contribute to the understanding of the evolution of vertebrate circadian timing regulation. The diversity of the group, with more than 3700 living species [53] exhibits a number of adaptations to their ecological niches, which include distinct daily activity patterns [54–57]. These adaptations raise intriguing questions about selective pressure acting on specific genes related to circadian activity control.…”

Section: Introductionmentioning

confidence: 99%

Characterization of the melanopsin gene (Opn4x) of diurnal and nocturnal snakes

et al. 2019

View full text Add to dashboard Cite

Background A number of non-visual responses to light in vertebrates, such as circadian rhythm control and pupillary light reflex, are mediated by melanopsins, G-protein coupled membrane receptors, conjugated to a retinal chromophore. In non-mammalian vertebrates, melanopsin expression is variable within the retina and extra-ocular tissues. Two paralog melanopsin genes were classified in vertebrates, Opn4x and Opn4m . Snakes are highly diversified vertebrates with a wide range of daily activity patterns, which raises questions about differences in structure, function and expression pattern of their melanopsin genes. In this study, we analyzed the melanopsin genes expressed in the retinas of 18 snake species from three families (Viperidae, Elapidae, and Colubridae), and also investigated extra-retinal tissue expression. Results Phylogenetic analysis revealed that the amplified gene belongs to the Opn4x group, and no expression of the Opn4m was found. The same paralog is expressed in the iris, but no extra-ocular expression was detected. Molecular evolutionary analysis indicated that melanopsins are evolving primarily under strong purifying selection, although lower evolutionary constraint was detected in snake lineages (ω = 0.2), compared to non-snake Opn4x and Opn4m (ω = 0.1). Statistical analysis of selective constraint suggests that snake phylogenetic relationships have driven stronger effects on melanopsin evolution, than the species activity pattern. In situ hybridization revealed the presence of melanopsin within cells in the outer and inner nuclear layers, in the ganglion cell layer, and intense labeling in the optic nerve. Conclusions The loss of the Opn4m gene and extra-ocular photosensitive tissues in snakes may be associated with a prolonged nocturnal/mesopic bottleneck in the early history of snake evolution. The presence of melanopsin-containing cells in all retinal nuclear layers indicates a globally photosensitive retina, and the expression in classic photoreceptor cells suggest a regionalized co-expression of melanopsin and visual opsins. Electronic supplementary material The online version of this article (10.1186/s12862-019-1500-6) contains supplementary material, which is available to authorized users.

show abstract

Daily Activity of Neotropical Dipsadid Snakes

Cited by 10 publications

References 35 publications

Daily activity patterns influence retinal morphology, signatures of selection, and spectral tuning of opsin genes in colubrid snakes

Daily activity patterns influence retinal morphology, signatures of selection, and spectral tuning of opsin genes in colubrid snakes

Retinal Topographic Maps: A Glimpse into the Animals’ Visual World

Characterization of the melanopsin gene (Opn4x) of diurnal and nocturnal snakes

Contact Info

Product

Resources

About