scholarly journals Ecological specialization, rather than the island effect, explains morphological diversification in an ancient radiation of geckos

2021 ◽  
Vol 288 (1965) ◽  
Author(s):  
Héctor Tejero-Cicuéndez ◽  
Marc Simó-Riudalbas ◽  
Iris Menéndez ◽  
Salvador Carranza
Keyword(s):  
Body Size ◽  
Morphological Change ◽  
Morphological Evolution ◽  
The Body ◽  
Habitat Specialization ◽  
Ecological Specialization ◽  
Morphological Diversification ◽  
Habitat Occupancy ◽  
Island Effect ◽  
Similar Body

Island colonists are often assumed to experience higher levels of phenotypic diversification than continental taxa. However, empirical evidence has uncovered exceptions to this ‘island effect’. Here, we tested this pattern using the geckos of the genus Pristurus from continental Arabia and Africa and the Socotra Archipelago. Using a recently published phylogeny and an extensive morphological dataset, we explore the differences in phenotypic evolution between Socotran and continental taxa. Moreover, we reconstructed ancestral habitat occupancy to examine if ecological specialization is correlated with morphological change, comparing phenotypic disparity and trait evolution between habitats. We found a heterogeneous outcome of island colonization. Namely, only one of the three colonization events resulted in a body size increase. However, in general, Socotran species do not present higher levels or rates of morphological diversification than continental groups. Instead, habitat specialization explains better the body size and shape evolution in Pristurus . Particularly, the colonization of ground habitats appears as the main driver of morphological change, producing the highest disparity and evolutionary rates. Additionally, arboreal species show very similar body size and head proportions. These results reveal a determinant role of ecological mechanisms in morphological evolution and corroborate the complexity of ecomorphological dynamics in continent–island systems.

scholarly journals Ecological specialization, rather than the island rule, explains morphological diversification in an ancient radiation of geckos

2021 ◽  
Author(s):  
Héctor Tejero-Cicuéndez ◽  
Marc Simó-Riudalbas ◽  
Iris Menéndez ◽  
Salvador Carranza
Keyword(s):  
Body Size ◽  
Morphological Change ◽  
Morphological Evolution ◽  
Habitat Specialization ◽  
Ecological Specialization ◽  
Island Rule ◽  
Morphological Diversification ◽  
Main Driver ◽  
Island System ◽  
Socotra Archipelago

Island colonists are often assumed to experience higher levels of phenotypic diversification than their continental sister taxa. However, empirical evidence shows that exceptions to the familiar "island rule" do exist. In this study, we tested this rule using a nearly complete sampled mainland-island system, the genus Pristurus, a group of sphaerodactylid geckos mainly distributed across continental Arabia and Africa and the Socotra Archipelago. We used a recently published phylogeny and an extensive dataset of morphological measures to explore whether island and mainland taxa share the same morphospace or if they present different dynamics of phenotypic evolution. Moreover, we used habitat data to examine if ecological specialization is correlated with morphological change, reconstructing the ancestral habitat states across the phylogeny to compare the level of phenotypic disparity and trait evolution between habitats. We found that insular species do not present higher levels or rates of morphological diversification than continental groups. Instead, habitat specialization provides insight into the evolution of body size and shape in Pristurus. In particular, the adaptation to exploit ground habitats seems to have been the main driver of morphological change, producing the highest levels of disparity and evolutionary rates. Additionally, arboreal species show very constrained body size and head proportions, suggesting morphological convergence driven by habitat specialization. Our results reveal a determinant role of ecological mechanisms in morphological evolution and corroborate the complexity of ecomorphological dynamics in mainland-island systems.

Warning signals promote morphological diversification in fossorial uropeltid snakes (Squamata: Uropeltidae)

2020 ◽  
Author(s):  
Vivek Philip Cyriac ◽  
Ullasa Kodandaramaiah
Keyword(s):  
Body Size ◽  
Free Space ◽  
Morphological Evolution ◽  
Environmental Constraints ◽  
Shape Evolution ◽  
Head Shape ◽  
Warning Signals ◽  
Morphological Diversification ◽  
Niche Expansion ◽  
Antipredator Defences

Abstract Many species possess warning colourations that signal unprofitability to predators. Warning colourations are also thought to provide prey with a ‘predator-free space’ and promote niche expansion. However, how such strategies release a species from environmental constraints and facilitate niche expansion is not clearly understood. Fossoriality in reptiles imposes several morphological limits on head and body size to facilitate burrowing underground, but many fossorial snakes live close to the surface and occasionally move above ground, exposing them to predators. In such cases, evolving antipredator defences that reduce predation on the surface could potentially relax the morphological constraints associated with fossoriality and promote morphological diversification. Fossorial uropeltid snakes possess varying degrees of conspicuous warning colourations that reduce avian predation when active above ground. We predicted that species with more conspicuous colourations will exhibit more robust body forms and show faster rates of morphological evolution because constraints imposed by fossoriality are relaxed. Using a comparative phylogenetic approach on the genus Uropeltis, we show that more conspicuous species tend to have more robust morphologies and have faster rates of head-shape evolution. Overall, we find that the evolution of warning colourations in Uropeltis can facilitate niche expansion by influencing rates of morphological diversification.

Reproductive patterns of European pond turtles differ between sites: a small scale scenario

2015 ◽  
Vol 36 (4) ◽  
pp. 339-349
Author(s):  
Marco A.L. Zuffi ◽  
Elena Foschi
Keyword(s):  
Body Size ◽  
Egg Production ◽  
Shell Height ◽  
The Body ◽  
Small Scale ◽  
Central Mediterranean ◽  
Population Structures ◽  
Body Sizes ◽  
Reproductive Females ◽  
Similar Body

From 1996 to 2002, we studied the body size, measures of reproductive strategy (relative clutch mass and delayed reproduction at sexual maturity), and reproductive output (clutch frequency and annual egg production) of female European Pond turtles,Emys orbicularis, at two sites separated by 12 km in central Mediterranean Tuscany (San Rossore and Camp Darby, central northern Italy). Females did not reproduce at the first appearance of external sexual characters, but reproduced at larger sizes, probably as older turtles. Among years, reproductive females were more common than were non-reproductive females, yet both groups had similar body sizes. Body size (carapace length and width, plastron length and width, shell height and body mass) varied between localities and among years. Body size differed between reproductive and non reproductive females in Camp Darby, but not in San Rossore females. Shell volume did not vary among years, nor between localities, nor between reproductive status. Reproductive females had higher body condition indices (BCI) than did non-reproductive females, while BCI did not differ between females laying one clutch and females laying multiple clutches. Clutch size did not vary among years. One clutch per year was much more frequent than multiple clutches, and multiple clutches were more frequent in Camp Darby than in San Rossore females, likely due to differences in population structures between sites.

SEASONAL VARIATION IN BODY SIZE AND REPRODUCTIVE CONDITION OF A PAPER WASP, POLISTES METRICUS (HYMENOPTERA: VESPIDAE)

1980 ◽  
Vol 112 (3) ◽  
pp. 239-248 ◽  
Author(s):  
Constance M. Haggard ◽  
George J. Gamboa
Keyword(s):  
Seasonal Variation ◽  
Body Size ◽  
Older Workers ◽  
The Body ◽  
Paper Wasp ◽  
Head Width ◽  
Reproductive Condition ◽  
Polistes Metricus ◽  
Colony Cycle ◽  
Similar Body

AbstractSeasonal morphometric analysis of 788 adult Polistes metricus Say showed that: (1) Queens sampled throughout the colony cycle were of similar body size but significantly smaller than fall gynes. (2) Queens’ ovaries are large in the spring, decline early in the colony cycle, peak near the mid-postemergence period and decline late in the colony cycle. (3) There are no significant correlations between head width, ovary width, and size of nest in workers or queens. (4) Early and late workers are small but workers emerging during the mid-postemergence period are large. (5) All workers and gynes emerge with small, similar sized ovaries but older workers may develop larger ovaries. (6) Queens are larger than early and late workers but the same size as workers emerging during the mid-postemergence period. (7) The class with the largest adults were intermediates collected when colonies began production of males. These adults, intermediate in fat content between workers and gynes, comprised a large proportion of females emerging late in the colony cycle. (8) The body size of gynes is independent of colony size. (9) Males were significantly more variable in body size than gynes.

scholarly journals Arboreality constrains morphological evolution but not species diversification in vipers

2017 ◽  
Vol 284 (1869) ◽  
pp. 20171775 ◽  
Author(s):  
Laura Rodrigues Vieira de Alencar ◽  
Marcio Martins ◽  
Gustavo Burin ◽  
Tiago Bosisio Quental
Keyword(s):  
New Species ◽  
Body Size ◽  
Morphological Evolution ◽  
Trait Evolution ◽  
Morphological Diversification ◽  
Body Sizes ◽  
Speciation Rates ◽  
Slender Bodies ◽  
Morphological Variants ◽  
Arboreal Snakes

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.

scholarly journals Morphological diversification in different trematode lineages: body size, host type, or time?

Parasitology ◽  
2009 ◽  
Vol 136 (1) ◽  
pp. 85-92 ◽  
Author(s):  
R. POULIN
Keyword(s):  
Body Size ◽  
Morphological Variation ◽  
The Body ◽  
Phenotypic Traits ◽  
Developmental Constraints ◽  
Anatomical Structures ◽  
Morphological Diversification ◽  
The Family ◽  
Phenotypic Diversification ◽  
Average Body

SUMMARYDifferent lineages experience different rates of phenotypic diversification, resulting in greater or lower variance in the expression of phenotypic traits among the species within a lineage. Here, morphological diversification is investigated in 14 different trematode families, based on a dataset comprising morphometric data on body size and 4 anatomical structures (oral sucker, ventral sucker, pharynx, cirrus sac) from 386 species. Three hypotheses are tested and subsequently rejected based on the empirical evidence. First, the degree of morphological variation in all traits within a trematode family, measured as the coefficient of variation among species, appears independent of the average body size of species belonging to that family. Second, patterns of morphological diversification appear similar whether endothermic or ectothermic vertebrates are used as definitive hosts. Third, phylogenetically older trematode lineages did not display greater morphological variation than younger, more derived ones, ruling out evolutionary time as an explanation. The results are consistent with developmental constraints acting on morphological diversification, since for some pairs of traits, variation in one trait is not independent of variation in another trait. More importantly, across most families, variation in body size was significantly more pronounced than variation in the relative sizes of the other morphological features. Trematode body size therefore varies widely while the general body architecture of the family is maintained. The fact that the evolution of the body plan is more conservative than that of body size suggests that the range of morphologies that can evolve in trematodes is constrained.

scholarly journals Evolution in Sinocyclocheilus cavefish is marked by rate shifts, reversals, and origin of novel traits

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Ting-Ru Mao ◽  
Ye-Wei Liu ◽  
Madhava Meegaskumbura ◽  
Jian Yang ◽  
Gajaba Ellepola ◽  
...  
Keyword(s):  
Body Size ◽  
Morphological Evolution ◽  
Principal Component ◽  
Fold Increase ◽  
The Body ◽  
Molecular Dating ◽  
Model Systems ◽  
Habitat Types ◽  
Related Condition ◽  
Environmental Pressures

Abstract Background Natural model systems are indispensable for exploring adaptations in response to environmental pressures. Sinocyclocheilus of China, the most diverse cavefish clade in the world (75 species), provide unique opportunities to understand recurrent evolution of stereotypic traits (such as eye loss and sensory expansion) in the context of a deep and diverse phylogenetic group. However, they remain poorly understood in terms of their morphological evolution. Therefore, we explore key patterns of morphological evolution, habitat utilization and geographic distribution in these fishes. Results We constructed phylogenies and categorized 49 species based on eye-related condition (Blind, Micro-eyed, and Normal-eyed), habitat types (Troglobitic—cave-restricted; Troglophilic—cave-associated; Surface—outside caves) and existence of horns. Geometric-morphometric analyses show Normal-eyed morphs with fusiform shapes segregating from Blind/Micro-eyed deeper bodied morphs along the first principal-component axis; second axis accounts for shape complexity related to horns. The body shapes showed a significant association with eye-related condition and horn, but not habitat types. Ancestral reconstructions suggest at least three independent origins of Blind morphs, each with different levels of modification in relation to their ancestral Normal-eyed morphs; Sinocyclocheilus are also pre-adapted for cave dwelling. Our geophylogeny shows an east-to-west diversification spanning Pliocene and Pleistocene, with early-diversifying Troglobitic species dominating subterranean habitats of karstic plains whereas predominantly Surface forms inhabit hills to the west. Evolutionary rates analyses suggest that lineages leading to Blind morphs were characterized by significant rate shifts, such as a slowdown in body size evolution and a 5–20 fold increase in rate of eye regression, possibly explained by limited resource availability. Body size and eye size have undergone reversals, but not horns, a trait entailing considerable time to form. Conclusions Sinocyclocheilus occupied cave habitats in response to drying associated with aridification of China during late Miocene and the Pliocene. The prominent cave-adaptations (eye-regression, horn-evolution) occur in clades associated with the extensive subterranean cave system in Guangxi and Guizhou provinces. Integration of morphology, phylogeny, rate analyses, molecular-dating and distribution show not only several remarkable patterns of evolution, but also interesting exceptions to these patterns signifying the diversification of Sinocyclocheilus as an invaluable model system to explore evolutionary novelty.

scholarly journals Evolution in Extremis: The When, How, and Why of Hawaiian Carabid Beetles

2019 ◽  
Vol 2 ◽  
Author(s):  
James Liebherr
Keyword(s):  
Sexual Selection ◽  
Body Size ◽  
Small Body ◽  
Carabid Beetle ◽  
Carabid Beetles ◽  
Habitat Specialization ◽  
Dispersal Ability ◽  
Ecological Specialization ◽  
Hawaiian Archipelago ◽  
Ecological Zones

The Hawaiian Archipelago is the most isolated oceanic island system in the World, separated from the nearest source areas by more than 4000 km. Five independent colonization events have resulted in diversification of a native carabid beetle fauna in excess of 400 known species. This diverse assemblage is disharmonic, with the major radiations restricted to the platynine genus Blackburnia Sharp (139 species), the subgenus Nesocidium Sharp of Bembidion Latreille (21 species), and the moriomorphine genus Mecyclothorax Sharp (239 species). Biogeographical, ecological, and evolutionary attributes of these three radiations are compared in order to determine factors crucial to carabid beetle diversification in this most-isolated situation. Biogeographical attributes include the age of origin of the constituent radiation, the island likely colonized by its common ancestor, and the biological characteristics, where known, of the colonizing ancestors for each independent radiation. Ecological attributes include the amount of habitat specialization undergone during each radiation, taking into account the primordial habitat colonized and the subsequent pattern of occupation of different habitat types during diversification. Evolutionary attributes include brachyptery, body-size evolution, sexual selection, and the evolution of specialized body conformations. It is shown that ecological specialization—i.e., occupation of a diverse array of ecological zones and microhabitats—in concert with reduced dispersal ability brought on by evolution of brachyptery are positively associated with enhanced levels of diversification. Comparing sympatric island faunas, it is shown that the latter operates synergistically with body size, as the smaller-bodied Mecyclothorax beetles speciate much more rapidly than the larger-bodied Blackburnia on Maui and Hawai῾i Island. Nonetheless, small body size does not gaurantee high diversity, as Bembidion beetles attain body sizes similar to Mecyclothorax beetles. Age of origin of a radiation is a subsidiary criterion for diversification given that the Mecyclothorax radiation commenced only 1.2 Ma, whereas it is hypothesized that Blackburnia have been resident in the Hawaiian archipelago for upwards of 28 Ma. Thus especially for Blackburnia we are constrained in our ability to know all of the evolutionary products of the radiation due to extinction of presumably all or nearly all species that occupied the now-sunken islands northwest of the oldest high island of Kauai. We are fortunate to know of several extinct Blackburnia species discovered in lowland subfossil deposits in Kauai, and these species provide crucial information now regarding future patterns of extinction. Sexual selection can be demonstrated for the Bembidion subgenus Nesocidium, and is a likely explanation for genitalic evolution over parts of the Mecyclothorax radiation, but it is not a phenomenon pervasively associated with increased levels of speciation.

scholarly journals The effect of orexin A application on the reaction of microglia cells body size stimulated by LPS injection

2019 ◽  
Vol 19 (1S) ◽  
pp. 232-233
Author(s):  
A P Synchikova ◽  
H Horiuchi ◽  
J Nabekura
Keyword(s):  
Body Size ◽  
Morphological Change ◽  
The Body ◽  
Microglia Activation ◽  
Cell Area ◽  
Orexin A ◽  
Activated Microglia ◽  
M1 Phenotype

The purpose of this study is to determine the effect of orexin A to LPS-activated microglia by investigating the morphological change. The effect of orexin on the level of LPS-activated microglia activation during the transition to the M1 phenotype was determined, which can be studied by measuring the cell area of the body.

The Body Size of Headstarted and Wild Juvenile European Pond Turtles (Emys orbicularis)

2017 ◽  
Vol 25 (2) ◽  
pp. 161
Author(s):  
Sławomir Mitrus ◽  
Bartłomiej Najbar ◽  
Adam Kotowicz ◽  
Anna Najbar
Keyword(s):  
Body Size ◽  
The Body ◽  
Emys Orbicularis
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