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The occipital regions of the braincases of two gigantic #ctenacanthiform #sharks are described from the Finis Shale (Virgilian, Upper Pennsylvanian, ca. 300 Ma) of Texas. Their original braincase lengths are estimated to have been 42.8–68.2 and 33.9–64.8 cm, based on comparison with smaller, more complete ctenacanthiform specimens (e.g., Tamiobatis). In complete ctenacanthiform body fossils (e.g., Goodrichthys), braincase length represents approximately 10% of total body length. This suggests that the Finis Shale sharks attained lengths up to 7 m (as large as modern great white sharks and Cretaceous cardabiodontids) and body weights of 1500–2500 kg. Thanks to Allison W. Bronson for this new paper! MAISEY, J.G. & BRONSON, A.W. & WILLIAMS, R.R. & MCKINZIE, M. 2017 A Pennsylvanian ‘supershark’ from Texas. Journal of Vertebrate Paleontology, in press http://www.tandfonline.com/doi/abs/10.1080/02724634.2017.1325369?journalCode=ujvp20 some press releases of this finding (from 2015): https://www.cnet.com/news/remains-of-giant-300-million-year-old-supershark-spotted-in-texas/ https://www.livescience.com/52506-texas-supershark.html https://www.sciencedaily.com/releases/2015/10/151029112238.htm
EEA 2017 CALL FOR PAPERS! The Dutch Elasmobranch Society is pleased to invite you to the 21st European Elasmobranch Association Scientific Conference from 12th-14th October in Amsterdam, the Netherlands. The conference will include a diverse programme of lectures and breakout sessions on key topics in the study of cartilaginous fishes. This year’s theme will be “The science you need, for the policy you want” to address one of the main objectives of the EEA which is to bridge the gap between scientists and policy makers and thus ensuring management of elasmobranchs is based on the best available science. more information: http://www.elasmobranch.nl/eea2017/
Thanks to Ross Dwyer for this new paper about the speartooth shark #Glyphis glyphis! The authors investigated the distribution and habitat utilisation of G. glyphis in the Wenlock River system, Queensland, Australia. Using acoustic transmitters and a network of fixed underwater acoustic hydrophones, the movements of 40 sharks (63 to 131.5 cm total length) were tracked over 22 mo, throughout 137 km of river and adjacent coastal embayment. LYON, B.J. & DWYER, R.G. & PILLANS, R.D. & CAMPBELL, H.A. & FRANKLIN, C.E. 2017 Distribution, seasonal movements and habitat utilisation of an endangered shark, Glyphis glyphis, from northern Australia. Marine Ecology Progress Series, 573: 203–213 http://www.int-res.com/abstracts/meps/v573/p203-213/ image: Lateral view of the head of Glyphis glyphis: preserved specimen NTM S 15351–001 (juvenile female 678 mm TL); preserved specimen NTM S 16217–001 (adolescent male 1447 mm TL) and central upper teeth and lower teeth of LWF E 218, immature female 1600–1800 mm TL. In: COMPAGNO, L.J.V. & WHITE, W.T. & LAST, P.R. (2008): Glyphis garricki sp. nov., a new species of river shark (Carcharhiniformes: Carcharhinidae) from northern Australia and Papua New Guinea, with a redescription of Glyphis glyphis (Müller & Henle, 1839), CSIRO Marine and Atmospheric Research Paper, 22: 203-226 http://shark-references.com/species/view/Glyphis-glyphis
Inuit tools with Greenland #shark teeth (#Somniosus microcephalus (BLOCH & SCHNEIDER, 1801)), National Museum of Denmark, Copenhagen, credit Markus Bühler read the full story: http://bestiarium.kryptozoologie.net/artikel/curiosity-of-the-day-inuit-tools-made-from-greenland-shark-jaws/
open access! The authors report the first record of one of the most common and widespread Palaeogene #selachians, the sand tiger shark #Brachycarcharias, from the Ypresian #Bolca Konservat-Lagerstätte. The combination of dental character of the 15 isolated teeth collected from the Pesciara and Monte Postale sites supports their assignment to the odontaspidid Brachycarcharias lerichei (Casier, 1946), a species widely spread across the North Hemisphere during the early Palaeogene. Thanks to Giuseppe Marramà for this new paper and the amazing image of Brachycarcharias! MARRAMÀ, G. & ENGELBRECHT, A. & CARNEVALE, G. & KRIWET, J. 2017 Eocene sand tiger sharks (Lamniformes, Odontaspididae) from the Bolca Konservat-Lagerstätte, Italy: palaeobiology, palaeobiogeography and evolutionary significance. Historical Biology, in press http://www.tandfonline.com/doi/full/10.1080/08912963.2017.1341503
The authors sampled 4 #shark species, #Prionace glauca, #Isurus oxyrinchus, #Carcharhinus falciformis and #Alopias pelagicus, and 3 #billfish species, #Xiphias gladius, #Istiophorus platypterus and Makaira nigricans, in order to gain understanding of their feeding ecology and trophic interactions through the use and combination of stomach content and stable isotope analyses. Thanks to Joan Navarro for this new paper! ROSAS-LUIS, R. & NAVARRO, J. & LOOR-ANDRADE, P. & FORERO, M.G. 2017 Feeding ecology and trophic relationships of pelagic sharks and billfishes coexisting in the central eastern Pacific Ocean. Marine Ecology Progress Series, 573: 191–201 http://www.int-res.com/abstracts/meps/v573/p191-201/ images: #Carcharhinus falciformis (MÜLLER & HENLE, 1839), © Julia Spät and Naturalis Biodiversity Center - RMNH.ART.194 - #Istiophorus platypterus (Shaw and Nodder) - Kawahara Keiga - 1823 - 1829 - Siebold Collection - pencil drawing http://shark-references.com/species/view/Carcharhinus-falciformis
Thanks to Andrea Di Cencio for this amazing image and the new paper! The authors report on two fossil sawfish rostral spines discovered in Pliocene marine mudstones at Tegoliccio (Tuscany, Italy) and here identified as belonging to the extant, currently Indo-Pacific genus Anoxypristis. Calcareous nanno-plankton analyses of the sediment embedding the pristid remains, coupled with biostratigraphic data from literature, allowed us to bracket the time of deposition between 3.61 Ma and 3.19 Ma. To our knowledge, the rostral spines described herein represent the first record of Anoxypristis in Italy. COLLARETA, A. & CASATI, S. & CATANZARITI, R. & DI CENCIO, A. 2017 First record of the knifetooth sawfish Anoxypristis (Elasmobranchii: Rhinopristiformes) from the Pliocene of Tuscany (central Italy). Neues Jahrbuch für Geologie und Paläontologie - Abhandlungen, 284 (3): 289-297 http://www.ingentaconnect.com/content/schweiz/njbgeol/2017/00000284/00000003/art00003 http://shark-references.com/species/view/Anoxypristis-cuspidata rostral spines of Anoxypristis ccf. cuspidata (LATHAM, 1794) discovered in Pliocene marine mudstones at Tegoliccio (Tuscany, Italy)
Stomach contents from 1221 Pacific spiny dogfish (Squalus suckleyi) were collected from the Gulf of Alaska over 2004–2006 and analyzed to determine predominant prey species. Pacific spiny dogfish in the Gulf of Alaska have a variable diet suggesting that they are generalist feeders. Of the 68.30% of stomachs with prey contents, the most important prey groups based on the percent prey-specific index of relative importance (%PSIRI) were shrimp (27.06%), cephalopods (17.16%), and forage fish (17.11%). Thanks to Wesley W. Strasburger for this new paper. TRIBUZIO, C.A. & STRASBURGER, W.W. & KRUSE, G.H. 2017 Do abiotic and ontogenetic factors influence the diet of a generalist predator? Feeding ecology of the Pacific spiny dogfish (Squalus suckleyi) in the northeast Pacific Ocean. Environmental Biology of Fishes, 100 (6): 685–701 https://link.springer.com/article/10.1007/s10641-017-0596-z http://shark-references.com/species/view/Squalus-suckleyi image: Squalus suckleyi (GIRARD, 1855) © Chris M. Wood, Canada
The purpose of the present study was to validate vertebral band-deposition rates of blue #sharks tagged and recaptured in the eastern Pacific Ocean. Vertebrae of 26 blue sharks marked with oxytetracycline (OTC) were obtained from tag–recapture activities to determine timing of centrum growth-band deposition. WELLS, R.J.D. & SPEAR, N. & KOHIN, S. 2017 Age validation of the blue shark (#Prionace glauca) in the eastern Pacific Ocean. Marine and Freshwater Research, 68 (6): 1130–1136 http://www.publish.csiro.au/MF/MF16054 Thanks to R. J. David Wells for this paper! image: Prionace glauca (LINNAEUS, 1758), © Mark Conlin, SWFSC Large Pelagics Program
Jonathan James Smart sent me this new paper! Thanks for the support! SMART, J.J. & CHIN, A. & TOBIN, A.J. & WHITE, W.T. & KUMASI, B. & SIMPFENDORFER, C.A. 2017 Stochastic demographic analyses of the silvertip shark (Carcharhinus albimarginatus) and the common blacktip shark (Carcharhinus limbatus) from the Indo-Pacific. Fisheries Research, 191: 95–107 http://www.sciencedirect.com/science/article/pii/S0165783617300620 http://shark-references.com/species/view/Carcharhinus-albimarginatus Highlights • Leslie matrix models were applied to two shark species from the Indo-Pacific. • Stochasticity was introduced to the models using Monte Carlo simulations. • Fishing mortality was varied to determine their susceptibility to fishing pressure. • Both species have low population growth rates when unfished. • Gauntlet fisheries are the most sustainable harvest strategy for both species. image: Carcharhinus albimarginatus (RÜPPELL, 1837), © Sirachai (Shin) Arunrugstichai, Center for Biodiversity in Peninsular Thailand, Yai Songkla, Thailand
Thank's to Periklis Kleitou, Demetris Kletou, Charalampos Antoniou and Giannis Giovos for this new open access paper! The presence of the bigeye thresher shark, #Alopias superciliosus in the Mediterranean has been poorly documented while in the eastern #Mediterranean, it has been confined on individual-based records and considered as scarce. Hereby, we provide evidences from two longline fishing trips of at least eight by-catch specimens. KLEITOU, P. & ANTONIOU, C. & GIOVOS, J. & KLETOU, D. 2017 How accurately are we describing the longline bycatch? The case of the ‘rare’ shark Alopias superciliosus in eastern Mediterranean. International Journal of Fisheries and Aquatic Studies, 5 (3): 375-378 http://www.fisheriesjournal.com/archives/2017/vol5issue3/PartE/5-3-19-253.pdf http://shark-references.com/species/view/Alopias-pelagicus image: © #FAO, Food and Agriculture Organization of the United Nations, Ebert, D.A. 2014. On Board Guide for the Identification of Pelagic Sharks and Rays of the Western Indian Ocean. Reproduced with permission, illustration by Marc Dando, Wildlife Illustrator
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open access! The image is showing an Australian freshwater crocodile (Crocodylus johnstoni) preying upon a freshwater #sawfish (#Pristis pristis), represents a rare example with considerable implications for conservation. For a fish that is pupped at around 800 mm total length (TL) with formidable weaponry, one would assume that rates of natural predation would be low; however, sawfish are at risk from other large predators in the tropical freshwaters of northern Australia, including the bull #shark (#Carcharhinus leucas), estuarine crocodile (Crocodylus porosus), and the Australian freshwater crocodile. MORGAN, D.L. & SOMAWEERA, R. & GLEISS, A.C. & BEATTY, S.J. & WHITTY, J.M. 2017 An upstream migration fought with danger: freshwater sawfish fending off sharks and crocodiles. Ecology, 98 (5): 1465–1467 http://onlinelibrary.wiley.com/doi/10.1002/ecy.1737/full http://shark-references.com/species/view/Pristis-pristis image by the authors
Thanks a lot to Raimundo Espinoza for this pdf! This new Shark and Ray species list for the USVI and Puerto Rico is the beginning of a new shark and ray education and outreach campaign in the US Caribbean. https://www.conservacionconciencia.org/ free download: http://docs.wixstatic.com/ugd/962a4a_00ac14297a66437a8ed146c5785f34b9.pdf
A rich and diverse ichthyofauna is described from the upper Oligocene (#Egerian) sands of Máriahalom, Hungary. The site is dominated by brackish molluscs that are preserved together with rare marine and terrestrial vertebrates. Based on the isolated #elasmobranch and bony fish remains, eight #sharks, four rays and seven teleost taxa were identified from Máriahalom. Many thanks to Márton Szabó for this new paper and the amazing image of Carcharoides catticus! SZABÓ, M. & BOTFALVAI, G. & KOCSIS, L. & CARNEVALE, G. & SZTANÓ, O. & EVANICS, Z. & RABI, M. 2017 Upper #Oligocene marine fishes from nearshore deposits of the Central #Paratethys (Máriahalom, Hungary). Palaeobiodiversity and Palaeoenvironments, in press https://link.springer.com/article/10.1007/s12549-017-0285-0 image credit by Márton Szabó: #Carcharoides catticus upper lateral tooth a) in lingual view, b) in mesial view and c) in labial view
We used data from a long-standing #shark longline survey as a case-study to demonstrate a method of estimating changing catch over variable soak times. Catches of longline sets with and without hook timers were modeled using generalized linear models (GLMs) to estimate catch conversion factors over varying soak times. Cassidy Peterson sent me this new paper! PETERSON, C.D. & GARTLAND, J. & LATOUR, R.L. 2017 "Novel use of hook timers to quantify changing catchability over soak time in longline surveys. Fisheries Research, 194: 99–111 http://www.sciencedirect.com/science/article/pii/S0165783617301376 image: #Rhizoprionodon terraenovae (RICHARDSON, 1836), © Andy Murch Elasmodiver.com
A new species of guitarfish! Rhinobatos austini sp. n. is described from the southwestern Indian Ocean based on four specimens collected from the KwaZulu-Natal Province, South Africa and from Mozambique. Many thanks to David Ebert, for this new paper and the permission to use the images! EBERT, D.A. & GON, O. 2017 #Rhinobatos austini n. sp., a new species of #guitarfish (Rhinopristiformes: Rhinobatidae) from the Southwestern Indian Ocean. Zootaxa, 4276 (2): 204–214 http://mapress.com/j/zt/article/view/zootaxa.4276.2.3 http://shark-references.com/species/view/Rhinobatos-austini
Many thanks to Dr. Carlos Martínez Pérez, Universitat de Valencia for a new paper about a #Miocene deep sea fauna! The study of a new Serravallian (Middle Miocene) locality from the Southeastern Spain has yielded a shark assemblage characterized by microremains of at least seven taxa (#Deania calcea, †#Isistius triangulus, †#Squaliolus cf. S. schaubi, †#Paraetmopterus sp., #Pristiophorus sp., #Scyliorhinus sp. and a cf. Squaliformes indet) of three different orders (Squaliformes, Pristiophoriformes and Carcharhiniformes). MARTÍNEZ-PÉREZ, C. & CARRILLO-BRICEÑO, J.D. & ESPARZA, C. & FERRÓN, H.G. & MANZANARES, E. & HAMMANN, C. & BOTELLA, H. 2017 A Serravallian (Middle Miocene) shark fauna from Southeastern Spain and its palaeoenvironment significance. Historical Biology, in press http://www.tandfonline.com/doi/abs/10.1080/08912963.2017.1326111?journalCode=ghbi20 image credit by Carlos Martínez Pérez: Paraetmopterus sp.
Fossil teeth show that sharks shrank in size and changed their diet after a major extinction event 66 million years ago. scientific paper: BELBEN, R.A. & UNDERWOOD, C.J. & JOHANSON, Z. & TWITCHETT, R.J. 2017 Ecological impact of the end-Cretaceous extinction on lamniform sharks. PLoS ONE, 12 (6): e0178294 http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0178294 press release: http://www.nhm.ac.uk/our-science/science-news/2017/june/sharks-got-smaller-after-mass-extinction-event.html?utm_source=fb-image-post-20170608&utm_medium=social&utm_campaign=general
Thanks to Philip Matich for this new paper! Blacktip shark (Carcharhinus limbatus) and bull shark (Carcharhinus leucas) concentrations were quantified using long-term coastal gill net survey data across five bay systems in Texas. Relationships between co-occurrence, and environmental factors and shark sizes were examined within and across species. Co-occurrence of blacktip sharks and bull sharks varied spatially and temporally, with a significant increase in interspecific co-occurrence from the 1970s to 2010s, and a significant decrease in bull shark concentrations through time. MATICH, P. & MOHAN, J.A. & PLUMLEE, J.D. & TINHAN, T. & WELLS, R.J.D. & FISHER, M. 2017 Factors shaping the co-occurrence of two juvenile shark species along the Texas Gulf Coast. Marine Biology, 164: 141 https://link.springer.com/article/10.1007/s00227-017-3173-2?wt_mc=alerts.TOCjournals http://shark-references.com/species/view/Carcharhinus-limbatus image: Carcharhinus limbatus (MÜLLER & HENLE, 1839), in UShaka Sea World, © Amada44
John A Finarelli sent me this new paper about Devil Rays! Thanks for the support! The authors developed a species-specific eDNA assay for the Chilean devil ray, Mobula tarapacana, to assess the capability of using eDNA to detect transient pelagic marine animals. For this pilot study, seawater samples taken at seamounts around the Azores (NE Atlantic) were tested to determine the suitability of this approach for detecting the target species. GARGAN, L.M. & MORATO, T. & PHAM, C.K. & FINARELLI, J.A. & CARLSSON, J.E.L. & CARLSSON, J. 2017 Development of a sensitive detection method to survey pelagic biodiversity using eDNA and quantitative PCR: a case study of devil ray at seamounts. Marine Biology, 164: 112 https://link.springer.com/article/10.1007/s00227-017-3141-x http://shark-references.com/species/view/Mobula-tarapacana
Just published and open access! Many thanks to Chris Duffin for this new paper! The isolated teeth of a new euselachian shark Artiodus prominens Ivanov and Duffin gen. et sp. nov. have been found in the Artinskian Stage (Early Permian) of Krasnoufimskie Klyuchiki quarry (Sverdlovsk Region, Middle Urals, Russia). IVANOV, A.O. & DUFFIN, C.J. & NAUGOLNYKH, S.V. 2017 A new euselachian shark from the early Permian of the Middle Urals, Russia. Acta Palaeontologica Polonica, 62 (2): 289-298 http://www.app.pan.pl/article/item/app003472017.html image by the authors: Teeth of the euselachian shark Artiodus prominens Ivanov and Duffin gen. et sp. nov. from the Artinskian (Early Permian) of Krasnoufimskie Klyuchiki quarry (Middle Urals, Russia).
NEW! Eastern Atlantic and Mediterranean Angel Shark Conservation Strategy! Eva MEyers sent me the new strategy paper! for more information please visit: http://angelsharknetwork.com/#action free download of the strategy paper: http://angelsharknetwork.com/wp-content/uploads/sites/16/2017/06/Angel-Shark-Conservation-Strategy_FINAL.pdf
The newsletter may/June is now online! http://shark-references.com/post/716 Subscribe to our newsletter! http://eepurl.com/sJNGb image: original image of Carcharodon lanceolatus in Agassiz, 1843 and a image of the holotype, now valid as Otodus angustidens (image by Jürgen Pollerspöck, www.shark-references.com) http://shark-references.com/post/358
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