Evolution, systematics and conservation of cartilaginous fish
Chondrichthyans (sharks, rays and skates) are an ancient, slowly evolving group of cartilaginous fish that paradoxically exhibited high species diversity, high rate of endemic taxa and high level of vulnerability to human activities and environmental pressures. In this fish, biological, ecological and evolutionary traits strongly affect the potential of adaptation and diversification of taxa.
The “Chondrichthyan” research topic addresses to disentangle and reconstruct the natural history of living sharks, rays and skates using prevalently genetic and genomic technologies. Population genetic structure, phylogegraphy, historical demography, effective population size, cryptic speciation, interspecific hybridization, historical biogeography and phylogenetics of Chondrichthyans are investigated by assessing the variation of genes, genomes and transcriptomes in relation to phenotypes and geography/oceanography.
Target taxa of the evolutionary investigations are mainly skates of the genus Raja, a moderately-diverse and monophyletic group of species inhabiting the Eastern Atlantic-Mediterranean. The evolution and diversification of this group appear to be occurred through allopatric and peripatric geographical speciation. These evolutionary processes were likely initiated by population structuring caused by oceanographic discontinuities followed by sibling speciation phenomena as intermediate evolutionary frames.
Massive DNA barcoding of demersal Chondrichthyans belonging to the Mediterranean and to the North-Eastern Atlantic, ranging from Iceland to Angolan/South African faunas greatly improved morphological taxonomy and systematics contributing effectively to correct species misidentification in scientific surveys, assessing more reliably species diversity and abundance. The setup of public repositories as the ELASMOMED DNA Barcode Reference Library can greatly and positively impact on fishery management and conservation plans.
Flag shark species for conservation and fishery such as the great white shark, sawfishes, and blue shark were targeted by local and EU research projects, in collaboration with several research groups and coupling the sampling in museums or at sea for tracing migration routes, population demography and connectivity and stock units.
More recent and forthcoming peer-reviewed research papers published on the “Chondrichthyan” topic are:
- Alice Ferrari, Fausto Tinti, Victoria Bertucci Maresca, Alessandro Velonà, Rita Cannas, Ioannis Thasitis, Filipe Oliveira Costa, Maria Cristina Follesa, Daniel Golani, Farid Hemida, Sarah J. Helyar, Cecilia Mancusi, Antonello Mulas, Fabrizio Serena, Letizia Sion, Marco Stagioni, Alessia Cariani, Natural history and molecular evolution of demersal Mediterranean sharks and skates inferred by comparative phylogeographic and demographic analyses, «PEERJ», 2018, 6, pp. 1 – 29
- Agostino, Leone; Ilenia, Urso; Dimitrios, Damalas; Jann, Martinsohn; Antonella, Zanzi; Stefano, Mariani; Emilio, Sperone; Primo, Micarelli; Fulvio, Garibaldi; Persefoni, Megalofonou; Luca, Bargelloni; Rafaella, Franch; David, Macias; Paulo, Prodöhl; Séan, Fitzpatrick; Marco, Stagioni; Fausto, Tinti; Alessia, Cariani, Genetic differentiation and phylogeography of Mediterranean-North Eastern Atlantic blue shark (Prionace glauca, L. 1758) using mitochondrial DNA: panmixia or complex stock structure?, «PEERJ», 2017, 5, pp. 1 - 18
- Cariani A, Messinetti S, Ferrari A, Arculeo M, Bonello JJ, Bonnici L, Cannas R, Carbonara P, Cau A, Charilaou C…, Tinti F: Improving the Conservation of Mediterranean Chondrichthyans: The ELASMOMED DNA Barcode Reference Library. PLoS ONE 2017, 12(1):e0170244.
- Frodella N, Cannas R, Velonà A, Carbonara P, Farrell ED, Fiorentino F, Follesa MC, Garofalo G, Hemida F, Mancusi C …, Tinti F, Cariani A,: Population connectivity and phylogeography of the Mediterranean endemic skate Raja polystigma and evidence of its hybridization with the parapatric sibling R. montagui. Marine Ecology Progress Series 2016, 554:99-113.
- Marino IAM, Riginella E, Cariani A, Tinti F, Farrell ED, Mazzoldi C, Zane L: New Molecular Tools for the Identification of 2 Endangered Smooth-Hound Sharks, Mustelus mustelus and Mustelus punctulatus. J Hered 2014, 106(1):123-130.
- Pasolini P, Ragazzini C, Zaccaro Z, Cariani A, Ferrara G, Gonzalez EG, Landi M, Milano I, Stagioni M, Guarniero I, Tinti F: Quaternary geographical sibling speciation and population structuring in the Eastern Atlantic skates (suborder Rajoidea) Raja clavata and R. straeleni. Mar Biol 2011, 158(10):2173-2186.