The evolution of endothermy in vertebrates is a major research topic in recent decades that has been tackled by a myriad of research disciplines including paleontology, anatomy, physiology, ...evolutionary and developmental biology. The ability of most mammals to maintain a relatively constant and high body temperature is considered a key adaptation, enabling them to successfully colonize new habitats and harsh environments. It has been proposed that in mammals the anterior nasal cavity, which houses the maxilloturbinal, plays a pivotal role in body temperature maintenance, via a bony system supporting an epithelium involved in heat and moisture conservation. The presence and the relative size of the maxilloturbinal has been proposed to reflect the endothermic conditions and basal metabolic rate in extinct vertebrates. We show that there is no evidence to relate the origin of endothermy and the development of some turbinal bones by using a comprehensive dataset of µCT-derived maxilloturbinals spanning most mammalian orders. Indeed, we demonstrate that neither corrected basal metabolic rate nor body temperature significantly correlate with the relative surface area of the maxilloturbinal. Instead, we identify important variations in the relative surface area, morpho-anatomy, and complexity of the maxilloturbinal across the mammalian phylogeny and species ecology.
ABSTRACT
Naked mole‐rats express many unusual traits for such a small rodent. Their morphology, social behaviour, physiology, and ageing have been well studied over the past half‐century. Many early ...findings and speculations about this subterranean species persist in the literature, although some have been repeatedly questioned or refuted. While the popularity of this species as a natural‐history curiosity, and oversimplified story‐telling in science journalism, might have fuelled the perpetuation of such misconceptions, an accurate understanding of their biology is especially important for this new biomedical model organism. We review 28 of these persistent myths about naked mole‐rat sensory abilities, ecophysiology, social behaviour, development and ageing, and where possible we explain how these misunderstandings came about.
Most research on mechanisms of aging is being conducted in a very limited number of classical model species, i.e., laboratory mouse (
Mus musculus
), rat (
Rattus norvegicus domestica
), the common ...fruit fly (
Drosophila melanogaster
) and roundworm (
Caenorhabditis elegans
). The obvious advantages of using these models are access to resources such as strains with known genetic properties, high-quality genomic and transcriptomic sequencing data, versatile experimental manipulation capabilities including well-established genome editing tools, as well as extensive experience in husbandry. However, this approach may introduce interpretation biases due to the specific characteristics of the investigated species, which may lead to inappropriate, or even false, generalization. For example, it is still unclear to what extent knowledge of aging mechanisms gained in short-lived model organisms is transferable to long-lived species such as humans. In addition, other specific adaptations favoring a long and healthy life from the immense evolutionary toolbox may be entirely missed. In this review, we summarize the specific characteristics of emerging animal models that have attracted the attention of gerontologists, we provide an overview of the available data and resources related to these models, and we summarize important insights gained from them in recent years. The models presented include short-lived ones such as killifish (
Nothobranchius furzeri
), long-lived ones such as primates (
Callithrix jacchus, Cebus imitator, Macaca mulatta
), bathyergid mole-rats (
Heterocephalus glaber, Fukomys spp.
), bats (
Myotis spp.
), birds, olms (
Proteus anguinus
), turtles, greenland sharks, bivalves
(Arctica islandica
), and potentially non-aging ones such as
Hydra
and
Planaria
.
We used nested clade phylogeographic analysis (NCPA) of mitochondrial DNA sequence data to examine the processes contributing to population structure in naked mole-rats. We examined sequence ...variation in the (1097 bp) control region D-loop of the mitochondrial genome in 303 individuals from 174 colonies of naked mole-rats (
Heterocephalus glaber
) located mainly within an 870 km
2
area in Meru National Park, Kenya. Four rivers were found to be correlated to a significant fragmentation inference in the NCPA. The largest pairwise divergence between haplotypes from populations separated by rivers was 2.74%, which was well over half of the divergence reported between the extremes of the distribution from southern Ethiopia to southern Kenya (4.6%). However, the size of the river (measured in current discharge) was not a good predictor of the amount of sequence divergence between populations separated by a river. It appears that a large-scale historical fragmentation event may have conflated fragmentation patterns on a smaller scale, when recent colonization and range expansion brought two old lineages together at a location with a relatively small river separating them.
The social mole-rats of the family Bathyergidae show elaborate social organisation that may include division of labour between breeders and non-breeders as well as across non-breeders within their ...groups. However, comparative behavioural data across the taxa are rare and contrasts and similarities between species are poorly understood. Field studies of social bathyergids usually involve capturing all group members until the entire group is captured. Because each animal is only captured once and traps are typically placed in close proximity to active foraging areas, the order in which animals are captured provides an indication of the foraging activity of different individuals and of the spatial organisation of the group within the burrow system. Here, we compare the association of capture order with breeding status, sex, and body mass in four species and subspecies of social bathyergids, which vary in group size and represent all three social genera within the family Bathyergidae. We show that in naked and Damaraland mole-rats (
Heterocephalus glaber
and
Fukomys damarensis
), male and female breeders are captured later than non-breeders, whereas in two different subspecies of the genus
Cryptomys
only female breeders are captured later than non-breeders. The effect sizes vary largely and are 10 times larger in naked mole-rats as compared to
Fukomys
and 3–4 times larger than in
Cryptomys
. Among non-breeders, sex effects are notably absent in all species and body mass predicted capture order in both naked and Damaraland mole-rats. In naked mole-rats, larger non-breeders were captured earlier than smaller ones, whereas in Damaraland mole-rats intermediate-sized non-breeders were captured first. Our data suggest that there are similarities in behavioural structure and spatial organisation across all social bathyergid species, though the most pronounced differences within groups are found in naked mole-rats.
This unique textbook introduces undergraduate students to quantitative models and methods in ecology, behavioral ecology, evolutionary biology, and conservation. It explores the core concepts shared ...by these related fields using tools and practical skills such as experimental design, generating phylogenies, basic statistical inference, and persuasive grant writing. And contributors use examples from their own cutting-edge research, providing diverse views to engage students and broaden their understanding.
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