Viviparity in the longest-living vertebrate, the Greenland shark (Somniosus microcephalus)

Carter, Anthony Michael; Soma, Hiroaki

doi:10.1016/j.placenta.2020.05.014

Cited by 9 publications

(5 citation statements)

References 19 publications

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“…Out of the three fish species, the Greenland shark was assessed to be the least vulnerable to climate change‐related impacts. The species' nonspecific habitat and dietary requirements, along with a reproductive strategy with no complexities mentioned in the literature, suggests that there are fewer known sources of disruption to their phenology from climate change than the other studied fish species (Carter & Soma, 2020; Devine et al, 2018; Nielsen et al, 2019). However, its long maturation time of at least 134 years is higher than most species, even when compared with other slow developing species like the bowhead whale (Nielsen et al, 2016).…”

Section: Discussionmentioning

confidence: 99%

A feasibility study for the application of climate change vulnerability assessments on species in the Tallurutiup Imanga National Marine Conservation Area

Cogger,

Filgueira,

Keenan

2024

Aquatic Conservation

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Climate change is disproportionately affecting Arctic ecosystems and their resident species, but knowledge gaps complicate conservation planning. A proof‐of‐concept application of existing trait‐based vulnerability assessment frameworks were applied to nine species from three different taxa (cetaceans, pinnipeds, marine fish) to determine their vulnerability under the RCP 8.5 emissions scenario. A literature review and data gap analysis were performed to quantify vulnerability and recommend future research priorities. Each assessed species was found to be highly vulnerable to climate change, with char, cod, and walrus being the most vulnerable. The largest data gaps include outdated or missing abundance measurements mortality rates in both marine mammals and fish, and reproductive behaviours for fish specifically. Future assessments should consider multiple emissions scenarios that match the ranges of migratory species not confined to the TINMCA. Providing a method to preliminarily evaluate climate change vulnerability may help mitigate issues brought by limited species experts, such as respondent fatigue. More refined scores will require the assistance of species experts, including biologists and Indigenous knowledge holders.

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Section: Discussionmentioning

confidence: 99%

A feasibility study for the application of climate change vulnerability assessments on species in the Tallurutiup Imanga National Marine Conservation Area

Cogger,

Filgueira,

Keenan

2024

Aquatic Conservation

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“…As for public outreach, the fact that viviparity in rays and squaliform sharks arose in the Mesozoic (‘the Age of dinosaurs’ to the general public) has potential to capture interest, as does the ‘megamamma’ (sic) whale shark, with its astonishing 300 embryos (Carter & Soma, 2020; Joung et al ., 1996). Likewise, the fact pregnant carcharhinids form placentas (‘like our own species’), while the sand tiger shark feeds her embryos via ‘intrauterine cannibalism’ has potential in engaging public attention.…”

Section: Discussionmentioning

confidence: 99%

Phylogenetic analysis of viviparity, matrotrophy, and other reproductive patterns in chondrichthyan fishes

Blackburn,

Hughes

2024

Biological Reviews

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The reproductive diversity of extant cartilaginous fishes (class Chondrichthyes) is extraordinarily broad, reflecting more than 400 million years of evolutionary history. Among their many notable reproductive specialisations are viviparity (live‐bearing reproduction) and matrotrophy (maternal provision of nutrients during gestation). However, attempts to understand the evolution of these traits have yielded highly discrepant conclusions. Here, we compile and analyse the current knowledge on the evolution of reproductive diversity in Chondrichthyes with particular foci on the frequency, phylogenetic distribution, and directionality of evolutionary changes in their modes of reproduction. To characterise the evolutionary transformations, we amassed the largest empirical data set of reproductive parameters to date covering nearly 800 extant species and analysed it via a comprehensive molecular‐based phylogeny. Our phylogenetic reconstructions indicated that the ancestral pattern for Chondrichthyes is ‘short single oviparity’ (as found in extant holocephalans) in which females lay successive clutches (broods) of one or two eggs. Viviparity has originated at least 12 times, with 10 origins among sharks, one in batoids, and (based on published evidence) another potential origin in a fossil holocephalan. Substantial matrotrophy has evolved at least six times, including one origin of placentotrophy, three separate origins of oophagy (egg ingestion), and two origins of histotrophy (uptake of uterine secretions). In two clades, placentation was replaced by histotrophy. Unlike past reconstructions, our analysis reveals no evidence that viviparity has ever reverted to oviparity in this group. Both viviparity and matrotrophy have arisen by a variety of evolutionary sequences. In addition, the ancestral pattern of oviparity has given rise to three distinct egg‐laying patterns that increased clutch (brood) size and/or involved deposition of eggs at advanced stages of development. Geologically, the ancestral oviparous pattern arose in the Paleozoic. Most origins of viviparity and matrotrophy date to the Mesozoic, while a few that are represented at low taxonomic levels are of Cenozoic origin. Coupled with other recent work, this review points the way towards an emerging consensus on reproductive evolution in chondrichthyans while offering a basis for future functional and evolutionary analyses. This review also contributes to conservation efforts by highlighting taxa whose reproductive specialisations reflect distinctive evolutionary trajectories and that deserve special protection and further investigation.

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“…Together, these observations suggest a potential niche for mammal somatic cells, in particular, to specialize in gestational transmission. And other viviparous organisms -from cacti, to sharks, to scorpions [14,[46][47][48][49][50][51] -likewise might, on finer study, turn out to harbor soma cells adept at colonizing nearby embryonic or fetal tissues, even if physiological details shape how readily such drive arises (perhaps, for example, more readily in animals than in viviparous plants, whose somatic pluripotency might moot the potential fitness advantage of gestational drive per se; and/or in taxa with long gestation, invasive placental physiology [52], and/or maternal-fetal immune tolerance) .…”

Section: Watching For Driversmentioning

confidence: 99%

Gestational somatic drive: Might ancestors' cell lines sneak into many descendant embryos?

Pearson

2023

Preprint

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In a typical person's body, most cells come from one recent zygote. But during gestation, maternal and even grand-maternal cells can cross the placenta into a developing embryo/fetus, to engraft as cell lines that may last long into adulthood. Together with other well established phenomena, from matrilineal endosymbionts to gestationally and socially transmitted microbes and tumors, such gestational cell traffic raises the question of whether some somatic cells in any mammal or other gestating lineage of life might specialize at engrafting in descendant embryos, to persist indefinitely outside the cycle of zygosis, somatic growth, and death that other body cells undergo. Here we explore the prospect of such gestational somatic drive, including potential hallmark clues to its presence, along with challenges to detecting or ruling it out, in nature.

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Viviparity in the longest-living vertebrate, the Greenland shark (Somniosus microcephalus)

Cited by 9 publications

References 19 publications

A feasibility study for the application of climate change vulnerability assessments on species in the Tallurutiup Imanga National Marine Conservation Area

A feasibility study for the application of climate change vulnerability assessments on species in the Tallurutiup Imanga National Marine Conservation Area

Phylogenetic analysis of viviparity, matrotrophy, and other reproductive patterns in chondrichthyan fishes

Gestational somatic drive: Might ancestors' cell lines sneak into many descendant embryos?

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