Habits and characteristics of arboreal snakes worldwide: arboreality constrains body size but does not affect lineage diversification

An increase in ecological opportunities, either through changes in the environment or acquisition of new traits, is frequently associated with an increase in species and morphological diversification. However, it is possible that certain ecological settings might prevent lineages from diversifying. Arboreality evolved multiple times in vipers, making them ideal organisms for exploring how potentially new ecological opportunities affect their morphology and speciation regimes. Arboreal snakes are frequently suggested to have a very specialized morphology, and being too large, too small, too heavy, or having short tails might be challenging for them. Using trait-evolution models, we show that arboreal vipers are evolving towards intermediate body sizes, with longer tails and more slender bodies than terrestrial vipers. Arboreality strongly constrains body size and circumference evolution in vipers, while terrestrial lineages are evolving towards a broader range of morphological variants. Trait-dependent diversification models, however, suggest similar speciation rates between microhabitats. Thus, we show that arboreality might constrain morphological evolution but not necessarily affect the rates at which lineages generate new species.

Download Full-text

Evolutionary shifts in extant mustelid (Mustelidae: Carnivora) cranial shape, body size and body shape coincide with the Mid-Miocene Climate Transition

Biology Letters ◽

10.1098/rsbl.2019.0155 ◽

2019 ◽

Vol 15 (5) ◽

pp. 20190155 ◽

Cited By ~ 3

Author(s):

Chris J. Law

Keyword(s):

Body Size ◽

Body Shape ◽

Environmental Changes ◽

Phenotypic Traits ◽

Adaptive Landscapes ◽

Global Cooling ◽

Body Sizes ◽

Climate Transition ◽

Lineage Diversification ◽

Cranial Shape

Environmental changes can lead to evolutionary shifts in phenotypic traits, which in turn facilitate the exploitation of novel adaptive landscapes and lineage diversification. The global cooling, increased aridity and expansion of open grasslands during the past 50 Myr are prime examples of new adaptive landscapes that spurred lineage and ecomorphological diversity of several mammalian lineages such as rodents and large herbivorous megafauna. However, whether these environmental changes facilitated evolutionary shifts in small- to mid-sized predator morphology is unknown. Here, I used a complete cranial and body morphological dataset to examine the timing of evolutionary shifts in cranial shape, body size and body shape within extant mustelids (martens, otters, polecats and weasels) during the climatic and environmental changes of the Cenozoic. I found that evolutionary shifts in all three traits occurred within extant mustelid subclades just after the onset of the Mid-Miocene Climate Transition. These mustelid subclades first shifted towards more elongate body plans followed by concurrent shifts towards smaller body sizes and more robust crania. I hypothesize that these cranial and body morphological shifts enabled mustelids to exploit novel adaptive zones associated with the climatic and environmental changes of the Mid to Late Miocene, which facilitated significant increases in clade carrying capacity.

Download Full-text

The evolution of startle displays: a case study in praying mantises

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2020.1016 ◽

2020 ◽

Vol 287 (1934) ◽

pp. 20201016 ◽

Cited By ~ 1

Author(s):

Marta Vidal-García ◽

James C. O'Hanlon ◽

Gavin J. Svenson ◽

Kate D. L. Umbers

Keyword(s):

Body Size ◽

Phylogenetic Signal ◽

Habitat Type ◽

Model System ◽

Good Representation ◽

Predator Prey ◽

Future Work ◽

Multiple Display ◽

Lineage Diversification

Anti-predator defences are typically regarded as relatively static signals that conceal prey or advertise their unprofitability. However, startle displays are complex performances that deter or confuse predators and can include a spectacular array of movements, colours and sounds. Yet, we do not fully understand the mechanisms by which they function, their evolutionary correlates, or the conditions under which they are performed and evolve. Here, we present, to our knowledge, the first phylogenetically controlled comparative analyses of startle displays including behavioural data, using praying mantises as a model system. We included 58 species that provide a good representation of mantis diversity and estimated the strength of phylogenetic signal in the presence and complexity of displays. We also tested hypotheses on potential evolutionary correlates, including primary defences and body size. We found that startle displays and morphological traits were phylogenetically conserved, whereas behavioural traits were highly labile. Surprisingly, body size was not correlated with display presence or complexity in phylogenetically controlled analyses. Species-rich clades were more likely to exhibit displays, suggesting that startle displays were probably involved in lineage diversification. We suggest that to further elucidate the conditions under which startle displays evolve, future work should include quantitative descriptions of multiple display components, habitat type, and predator communities. Understanding the evolution of startle displays is critical to our overall understanding of the theory behind predator–prey dynamics.

Download Full-text

The Relative Importance of Body Size and Paleoclimatic Change as Explanatory Variables Influencing Lineage Diversification Rate: An Evolutionary Analysis of Bullhead Catfishes (Siluriformes: Ictaluridae)

Systematic Biology ◽

10.1080/10635150801902193 ◽

2008 ◽

Vol 57 (1) ◽

pp. 116-130 ◽

Cited By ~ 32

Author(s):

Michael Hardman ◽

Lotta M. Hardman

Keyword(s):

Body Size ◽

Diversification Rate ◽

Evolutionary Analysis ◽

Relative Importance ◽

Explanatory Variables ◽

Lineage Diversification

Download Full-text

Morphological evolution in relationship to sidewinding, arboreality and precipitation in snakes of the family Viperidae

Biological Journal of the Linnean Society ◽

10.1093/biolinnean/blaa208 ◽

2021 ◽

Author(s):

Jessica L Tingle ◽

Theodore Garland

Keyword(s):

Body Size ◽

Model Comparison ◽

Morphological Evolution ◽

Mean Annual Precipitation ◽

Climate Variables ◽

Body Proportions ◽

Meristic Characters ◽

The Family ◽

Long Tails ◽

Arboreal Snakes

Abstract Compared with other squamates, snakes have received relatively little ecomorphological investigation. We examined morphometric and meristic characters of vipers, in which both sidewinding locomotion and arboreality have evolved multiple times. We used phylogenetic comparative methods that account for intraspecific variation (measurement error models) to determine how morphology varied in relationship to body size, sidewinding, arboreality and mean annual precipitation (which we chose over other climate variables through model comparison). Some traits scaled isometrically; however, head dimensions were negatively allometric. Although we expected sidewinding specialists to have different body proportions and more vertebrae than non-sidewinding species, they did not differ significantly for any trait after correction for multiple comparisons. This result suggests that the mechanisms enabling sidewinding involve musculoskeletal morphology and/or motor control, that viper morphology is inherently conducive to sidewinding (‘pre-adapted’) or that behaviour has evolved faster than morphology. With body size as a covariate, arboreal vipers had long tails, narrow bodies and lateral compression, consistent with previous findings for other arboreal snakes, plus reduced posterior body tapering. Species from wetter environments tended to have longer tails, wider heads and reduced anterior tapering. This study adds to the growing evidence that, despite superficial simplicity, snakes have evolved various morphological specializations in relationship to behaviour and ecology.

Download Full-text