Mammal madness: is the mammal tree of life not yet resolved?

Foley, Nicole M.; Springer, Mark S.; Teeling, Emma C.

doi:10.1098/rstb.2015.0140

Cited by 215 publications

(213 citation statements)

References 118 publications

(253 reference statements)

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“…The vision‐related nuclei of the dorsal thalamus of the tree pangolin do not appear to be specialized in any specific way, although it is likely that the lateral posterior nucleus will be composed of up to three subdivisions based on retinal (Lee et al, ) and collicular (Manger, Restrepo, & Innocenti, ) inputs, which were not examined in the current study. Despite this, the visual thalamus of the tree pangolin displays an organization typically identified for Eutherian mammals that do not have visual specializations; however, this generalized organization is of interest in terms of the phylogenetic relationships of the pangolins, being the recognized sister group to the carnivores (Arnason et al, ; Foley et al, ; Murphy et al, ). Carnivores are known to be visually specialized mammals, and this is reflected in the organization of their visual thalamus.…”

Section: Discussionmentioning

confidence: 99%

The brain of the tree pangolin (Manis tricuspis). V. The diencephalon and hypothalamus

Imam

Bhagwandin

Ajao

et al. 2019

J of Comparative Neurology

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The diencephalon (dorsal thalamus, ventral thalamus, and epithalamus) and the hypothalamus, play central roles in the processing of the majority of neural information within the central nervous system. Given the interactions of the diencephalon and hypothalamus with virtually all portions of the central nervous system, the comparative analysis of these regions lend key insights into potential neural, evolutionary, and behavioral specializations in different species. Here, we continue our analysis of the brain of the tree pangolin by providing a comprehensive description of the organization of the diencephalon and hypothalamus using a range of standard and immunohistochemical staining methods. In general, the diencephalon and hypothalamus of the tree pangolin follow the organization typically observed across mammals. No unusual structural configurations of the ventral thalamus, epithalamus, or hypothalamus were noted. Within the dorsal thalamus, the vast majority of typically identified nuclear groups and component nuclei were observed. The visual portion of the tree pangolin dorsal thalamus appears to be organized in a manner not dissimilar to that seen in most nonprimate and noncarnivore mammals, and lacks certain features that are present in the closely related carnivores. Within the ventral medial geniculate nucleus, a modular organization, revealed with parvalbumin neuropil immunostaining, is suggestive of specialized auditory processing in the tree pangolin. In addition, a potential absence of hypothalamic cholinergic neurons is suggestive of unusual patterns of sleep. These observations are discussed in an evolutionary and functional framework regarding the phylogeny and life history of the pangolins.

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Section: Discussionmentioning

confidence: 99%

The brain of the tree pangolin (Manis tricuspis). V. The diencephalon and hypothalamus

Imam

Bhagwandin

Ajao

et al. 2019

J of Comparative Neurology

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“…Annotated gene sequences for CASP1, RIG-I, IRF3,NLRP3,ASC,TBK1,STING and TNF were downloaded from GenBank (Benson et al, 2015) for a range of mammalian species. These data represented 12 mammalian orders, with species from all four eutherian superorders, spanning more than 100 million years of mammalian evolution (derived from Meredith et al, 2011; laurasiatherian topology based on Foley et al, 2016; Myotis toplogy based on Ruedi et al, 2013) (Fig. S1).…”

Section: Positive Selection Testsmentioning

confidence: 99%

A Potent Anti-Inflammatory Response in Bat Macrophages May Be Linked to Extended Longevity and Viral Tolerance

Kacprzyk

Hughes

Pålsson-McDermott

et al. 2017

Acta Chiropterologica

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Bats are unique among mammals given their ability to fly, apparent tolerance of deadly viruses and extraordinary longevity. We propose that these traits are linked and driven by adaptations of the innate immune system. To explore this hypothesis we challenged macrophages from the greater mouse-eared bat, Myotis myotis and the house mouse, Mus musculus with Toll Like Receptors (TLRs) ligands, lipopolysaccharides, LPS and polyinosinic-polycytidylic acid, Poly(I:C). Macrophages from both species presented a high level of mRNA induction of inferon β (INF-β), tumor necrosis factor (TNF) and interleukin-1β (Il-1β). However, in bat macrophages, this antiviral, proinflammatory response was balanced by a sustained high-level transcription of the anti-inflammatory cytokine Il-10, which was not observed in mouse, potentially resulting from adaptive regulation in bats.Additionally, phylogenomic selection tests across the basal divergences in mammals (n = 39) uncovered bat-specific adaptations in six genes involved in antiviral and proinflammatory signalling. Based on this pilot study, we put forward a hypothesis that bats may have evolved unique anti-inflammatory responses to neutralize proinflammatory stimuli resulting from flight. This in turn may drive their extraordinary longevity and viral tolerance by limiting inflammation driven ageing and infection-induced immunopathology. Further data from other individuals and bat species are required to advance this intriguing hypothesis.

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“…The highly derived morphological characteristics of the pangolins provide some of the more cogent examples of morphological evolutionary convergence, and have led to many debates regarding their taxonomy. The Pholidota were formerly grouped with armadillos and anteaters in the Edentata or Xenarthra and Tubulidentata (aardvark), due to their shared myrmecophagic diet and superficial morphological similarities (Norman & Ashley, ; Reiss, ), but recent phylogenetic analyses, based on mitochondrial and nuclear gene sequencing, suggest that the Pholidota are a sister group to the Carnivora (Arnason et al, ; Foley, Springer, & Teeling, ; Yu et al, ). Thus, this initial study, of a planned series of studies of the tree pangolin brain, aims to provide general information about the appearance and size of the central nervous system.…”

Section: Introductionmentioning

confidence: 99%

The brain of the tree pangolin (Manis tricuspis). I. General appearance of the central nervous system

Imam

Ajao

Bhagwandin

et al. 2017

J of Comparative Neurology

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Here, we describe the superficial appearance of the brain of the rarely studied tree pangolin. Phylogenetic analyses have placed the pangolins, order Pholidota, as a sister group to the order Carnivora. The majority of features visible on the surface of the tree pangolin brain, and its overall appearance can be described as typically mammalian. The pattern of sulci and gyri, while simple, appears very similar to that observed in carnivores. Two derived features of the Pholidota were observed, the first being the rostral decussation of the pyramidal tract, which instead of occurring at the spinomedullary junction, decussates at the level of the caudal pole of the facial nerve nucleus in the rostral medulla oblongata. This appears to be related to the need for voluntary control of the tongue, with a potentially enlarged corticobulbar tract ending in the hypoglossal nucleus. The second derived feature is the very short spinal cord, which terminates midway along the thoracic vertebrae before giving rise to a long and extensive cauda equina. This foreshortened spinal cord appears to be related to anisotropic growth of the somatic and neural elements following early development of the central nervous system. The olfactory system appears to be generally enlarged and is likely the predominant sense used in foraging. Vision and hearing do not appear specialized based on the relative size of the superior and inferior colliculi, but potential somatic specializations indicate that the somatosensory system is heavily relied upon for food consumption and prehensile tail usage.

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Mammal madness: is the mammal tree of life not yet resolved?

Cited by 215 publications

References 118 publications

The brain of the tree pangolin (Manis tricuspis). V. The diencephalon and hypothalamus

The brain of the tree pangolin (Manis tricuspis). V. The diencephalon and hypothalamus

A Potent Anti-Inflammatory Response in Bat Macrophages May Be Linked to Extended Longevity and Viral Tolerance

The brain of the tree pangolin (Manis tricuspis). I. General appearance of the central nervous system

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