Global shifts in species richness have shaped carpet shark evolution

Abstract

Background The evolutionary processes that shape patterns of species richness in marine ecosystems are complex and may differ between organismal groups. There has been considerable interest in understanding the evolutionary processes that led to marine species richness being concentrated in specific geographical locations. In this study we focus on the evolutionary history of a group of small-to-medium sized sharks known as carpet sharks. While a few carpet shark species are widespread, the majority of carpet shark species richness is contained within a biodiversity hotspot at the boundary of the Indian and Pacific oceans. We address the significance of this biodiversity hotspot in carpet shark evolution and speciation by leveraging a rich fossil record and molecular phylogenetics to examine the prehistoric distribution of carpet sharks. Results We find that carpet sharks species richness was greatest in shallow seas connected to the Atlantic Ocean during the Late Cretaceous, but that there was a subsequent loss of biodiversity in Atlantic waters. Fossil evidence from sites in close geographic proximity to the current center of carpet shark diversity are generally restricted to younger geologic strata. Conclusions From this data we conclude that (1) center of carpet shark biodiversity has shifted during the last 100 million years, (2) carpet sharks have repeatedly dispersed to nascent habitat (including to their current center of diversity), and (3) the current center of carpet shark biodiversity conserves lineages that have been extirpated from this prehistoric range and is a source of new carpet shark species. Our findings provide insights into the roles of marine biodiversity hotspots for higher-tropic level predators and the methods applied here can be used for additional studies of shark evolution.

Shark mandible evolution reveals patterns of trophic and habitat-mediated diversification

“…found that in deep sea squaliforms high speciation rates are associated with bioluminescence. Additionally, the diversification pattern for galeomorphs in reefs is supported by a rather recent diversification event in orectolobiforms 71 , which also is supported by the fossil record of orectolobiforms 72 . Our results show both significant levels of morphological disparity and elevated rates of morphological evolution (Fig.…”

Exploration of the Nurse Shark (Ginglymostoma cirratum) Plasma Immunoproteome Using High-Resolution LC-MS/MS

“…To this end, we mapped our LC-MS/MS data against the predicted proteins from the whale shark genome ( 37 ). Nurse shark and whale shark are members of the same Order, the Orectolobiformes (carpet sharks), but are evolutionarily separated by approximately 100 million years ( 68 ). Here, 297 MPGs containing 477 proteins were identified, 47.4% and 27.2% less, respectively, than when using the nurse shark transcriptome.…”

“…In our second approach, we used the annotated draft genome of a related shark species, the whale shark, as our reference database. Despite approximately 100 million years of evolutionary separation between the two shark species ( 68 ), this strategy still permitted the identification of 297 nurse shark plasma proteins, i.e., roughly half the number identified with our nurse shark transcriptome. Among the proteins identified were several apolipoproteins and coagulation factors, in addition to key immune mediators including complement cascade components and Igs.…”

The tangled biogeographic history of tarantulas: An African centre of origin rules out the centrifugal model of speciation

“…In many groups, such as the plant family Solanaceae (Dupin et al, 2017), sorghum (Chala et al, 2011), oak gall wasp (Rokas et al, 2003), plant genus Dyckia (Pinangé et al, 2017), land snail genus Monacha (Neiber & Hausdorf, 2017) and potato late blight pathogen Phytophthora infestans (Wang et al, 2017), the centre of origin harbours the highest genetic diversity, following a centrifugal model of speciation (Briggs, 2000; Singh et al, 2021). While in groups like Nephilid spiders (Turk et al, 2020), the plant families Chrysobalanaceae (Bardon et al, 2013) and Dipterocarpaceae (Bansal et al, 2022), carpet sharks (Boyd & Seitz, 2021), flying squirrels (Lu et al, 2013) and red pines (Walter & Epperson, 2001), the centre of greatest diversity is not at the centre of origin. The reasons for this shift in the centre of diversity are manifold.…”

“…Chrysobalanaceae (Bardon et al, 2013) and Dipterocarpaceae (Bansal et al, 2022), carpet sharks (Boyd & Seitz, 2021), flying squirrels (Lu et al, 2013) and red pines (Walter & Epperson, 2001), the centre of greatest diversity is not at the centre of origin. The reasons for this shift in the centre of diversity are manifold.…”