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Formation of sedimentary layers of white clay, Tamilnadu, India

Fossil site for wood fossils, Tamilnadu, India

Fossil site in Kerala, India

Fossil wood park maintained by geological survey of India at Tamilnadu

Cretaceous fossil sites india

Fossils in rack:-Cyad

Fossils in rack:-echiniderms

Fossils in rack:-Rastellum sp

Pre-historic seabed, Cretaceous period

WFS News: Oldest Green Algae Fossil

June 18th, 2020

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Fossilized Proterocladus antiquus VIRGINIA TECH

A newly discovered fossil species of green algae indicates that photosynthesis originated in plants at least 1 billion years ago, paleobiologists reported in Nature Ecology & Evolution yesterday (February 24). The discovery of Proterocladus antiquus helps pinpoint what has been a very broad estimation of when the chlorophyte group of green algae, the relatives of modern plants’ ancestors, evolved.

Artist’s rendition of Proterocladus antiquus DINGHUA YANG

“Previously, the oldest widely accepted fossilized green algae was about 800 million years old,” Timothy Gibson, a postdoc at Dartmouth College who was not involved with the study, tells Live Science. “This work confirms what many have expected based on the existing, though sparse fossil record, which is that green algae likely existed about a billion years ago.”

P. antiquus was a marine, multicellular eukaryote with an asymmetric branched structure about 2 mm in length—making it one of the largest organisms of its time, according to The Guardian. “There are some modern green seaweeds that look very similar to the fossils that we found,” coauthor Shuhai Xiao of Virginia Tech says in a press release. “A group of modern green seaweeds, known as siphonocladaleans, are particularly similar in shape and size to the fossils we found.”

Xiao’s postdoc Qing Tang found more than 1,000 P. antiquus fossils while using a microscope to examine rock samples from the silty shale and mudstone of what’s known as the Nanfen Formation in northern China, deposited roughly 1 billion years ago. Tang tells Live Science that the algae’s oxygen production may have had a significant effect on the marine ecosystem.

“Considering the abundant occurrence of Proterocladus in the Nanfen Formation, chlorophytes may have played notable ecological and geobiological roles, at least locally if not globally, before the Cryogenian,” 720 million–635 million years ago, the researchers write in their report.

Source: Article by Kerry Gren, The Scientist.com

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WFS News: The Permian-Triassic extinction was directly responsible for disrupting ocean chemistry

June 17th, 2020

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@WFS,World Fossil Society,Riffin T Sajeev,Russel T Sajeev

A new study shows for the first time that the collapse of terrestrial ecosystems during Earth’s most deadly mass extinction event was directly responsible for disrupting ocean chemistry.

The international study, led by the University of Leeds, highlights the importance of understanding the inter-connectedness of ecosystems as our modern environment struggles with the devastating effects of a rapidly warming planet.

The Permian-Triassic extinction, also known as the Great Dying, took place roughly 252 million years ago. It saw the loss of an estimated 90% of marine species, 70% of land species, widespread loss of plant diversity and extreme soil erosion.

While the exact cause of the terrestrial mass extinction is still debated, it is becoming apparent that the terrestrial ecosystems were wiped out prior to the marine ecosystems. However, until now it was unclear if or how the terrestrial extinction consequently impacted the chemistry of Earth’s ancient oceans.

The team built a computer model that mapped chemical changes in Earth’s oceans during the period of the Permian-Triassic extinction. The model tracks the cycling of the poisonous element mercury, which is emitted from volcanoes but also gets incorporated into living organisms. By tracing both the mercury and carbon cycles, and comparing to measurements in ancient rocks, the team were able to separate out biological and volcanic events.

This revealed that a massive collapse of terrestrial ecosystems cascaded organic matter, nutrients, and other biologically-important elements into the marine system.

While further research is needed to understand the exact effect this had on marine life, the fact that many marine species rely on chemical stability in their environment means that it is unlikely it was without consequence.

Study co-author Dr Jacopo Dal Corso, who conceived the study during a research placement at Leeds said: “In this study we show that during the Permian-Triassic transition, roughly. 252 million years ago, the widespread collapse of the terrestrial ecosystems caused sudden changes in marine chemistry.

“This likely played a central role in triggering the most severe known marine extinction in Earth’s history. This deep-time example shows how important the terrestrial reservoir is in regulating global biogeochemical cycles and calls for the greater conservation of these ecosystems.”

Study co-author Dr Benjamin Mills, from the School of Earth and Environment at Leeds said: “252 million years ago the effects of mass plant death and soil oxidation appear to have seriously altered the chemistry of the oceans. This is an uncomfortable parallel with our own human-driven land use change, and we too are transferring large quantities of nutrients and other chemicals to the oceans.

“As we look to re-start the world’s economies in the wake of the current pandemic, protecting our life-sustaining ecosystems should be a priority.”

Journal Reference:

Jacopo Dal Corso, Benjamin J. W. Mills, Daoliang Chu, Robert J. Newton, Tamsin A. Mather, Wenchao Shu, Yuyang Wu, Jinnan Tong, Paul B. Wignall. Permo–Triassic boundary carbon and mercury cycling linked to terrestrial ecosystem collapse. Nature Communications, 2020; 11 (1) DOI: 10.1038/s41467-020-16725-4

University of Leeds. “New insight into the Great Dying.” ScienceDaily. ScienceDaily, 11 June 2020. <www.sciencedaily.com/releases/2020.

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WFS News: Fossil bite marks of Theropod connected with feeding nature

June 14th, 2020

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@WFS,World Fossil Society,Riffin T Sajeev,Russel T Sajeev

Types of bite marks observed in the MMQ assemblage with arrows indicating features of note.
A, striated marks produced by ziphodont tooth on an Allosaurus sp. pedal claw (MWC 7263); B, a striated score on an Allosaurus sp. vertebral centrum (MWC 8675); C, a score on an Apatosaurus sp. rib fragment (MWC 3853); D, a dense cluster of furrows on a distal Apatosaurus sp. pubis (MWC 861); E, a puncture (white arrow) and a pit (yellow arrow) on an Allosaurus sp. caudal vertebral centrum; F, a dense cluster of striated furrows Apatosaurus sp. ischium (MWC 4011). All scale bars equal 10 mm.

Bite marks provide direct evidence for trophic interactions and competition in the fossil record. However, variations in paleoecological dynamics, such as trophic relationships, feeding behavior, and food availability, govern the frequency of these traces. Theropod bite marks are particularly rare, suggesting that members of this clade might not often focus on bone as a resource, instead preferentially targeting softer tissues. Here, we present an unusually large sample of theropod bite marks from the Upper Jurassic Mygatt-Moore Quarry (MMQ). We surveyed 2,368 vertebrate fossils from MMQ in this analysis, with 684 specimens (28.885% of the sample) preserving at least one theropod bite mark. This is substantially higher than in other dinosaur-dominated assemblages, including contemporaneous localities from the Morrison Formation. Observed bite marks include punctures, scores, furrows, pits, and striations. Striated marks are particularly useful, diagnostic traces generated by the denticles of ziphodont teeth, because the spacing of these features can be used to provide minimum estimates of trace maker size. In the MMQ assemblage, most of the striations are consistent with denticles of the two largest predators known from the site: Allosaurus and Ceratosaurus. One of the bite marks suggests that a substantially larger theropod was possibly present at the site and are consistent with large theropods known from other Morrison Formation assemblages (either an unusually large Allosaurus or a separate, large-bodied taxon such as Saurophaganax or Torvosaurus). The distribution of the bite marks on skeletal elements, particularly those found on other theropods, suggest that they potentially preserve evidence of scavenging, rather than active predation. Given the relative abundances of the MMQ carnivores, partnered with the size-estimates based on the striated bite marks, the feeding trace assemblage likely preserves the first evidence of cannibalism in Allosaurus.

Shed lateral tooth of Allosaurus sp. (MWC 5011) found at the Mygatt-Moore Quarry, white arrow indicates the distal denticles.Mesial denticles are present on such teeth, but were not preserved in this specimen.

Dry season at the Mygatt-Moore Quarry showing Ceratosaurus and Allosaurus fighting over the desiccated carcass of another theropod.Illustration by Brian Engh (dontmesswithdinosaurs.com).

Citation: Drumheller SK, McHugh JB, Kane M, Riedel A, D’Amore DC (2020) High frequencies of theropod bite marks provide evidence for feeding, scavenging, and possible cannibalism in a stressed Late Jurassic ecosystem. PLoS ONE 15(5): e0233115. https://doi.org/10.1371/journal.pone.0233115

Editor: David M. Lovelace, University of Wisconsin Madison, UNITED STATES

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WFS News: The last known freshwater coelacanths

June 13th, 2020

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@WFS,World Fossil Society,Riffin T Sajeev,Russel T Sajeev

The last known freshwater coelacanths: New Late Cretaceous mawsoniid

remains (Osteichthyes: Actinistia) from Southern France

Abstract

Coelacanths are iconic fishes represented today by a single marine genus. The group was a little bit more diversified in the Mesozoic, with representatives in marine and continental environments in the Late Cretaceous. Here we describe isolated skull bones of the last know freshwater coelacanths found in several fossil sites from the Early Campanian to the Early Maastrichtian of Southern France (in the Departments of Aude, Bouches-du-Rhône, Hérault, and Var). The sample does not allow distinguishing different species, and all material is referred to Axelrodichthys megadromos Cavin, Valentin, Garcia originally described from the locality of Ventabren in Southern France. A reconstruction of the skull is proposed. Previously unrecognized features are described, including parts of the postparietal portion of the skull, of the suspensorium and of the mandible. The new data confirm the assignation of the species to the mawsoniids, and more specifically to Axelrodichthys. A cladistic analysis scoring new character states provides a similar topology than a previous analysis, i.e. A. megadromos is placed in a polytomy with Axelrodichthys araripensis and Lualabaea lerichei, two species from the Early Cretaceous of Brazil and from the Late Jurassic of the Democratic Republic of the Congo, respectively. A. megadromos appears to have been restricted to freshwater environments, to the contrary of oldest Western Gondwanan representatives of the family that were able to live in brackish and marine waters. A. megadromos is the last representative of the mawsoniids and its occurrence in Europe is probably the result of a dispersal event from Western Gondwana that happened somewhen in the Cretaceous. Based on the available data, the mawsoniids went extinct in the mid-Maastrichthian, i.e. before the end-Cretaceous mass extinction. But it is possible that the fossil record of this family, which has been only recently recognized in Late Cretaceous European deposits, will geographically and stratigraphically widen with further discoveries.

Axelrodichthys megadromos, Velaux—La Bastide Neuve.Parasphenoid (MMS/VBN.09.001 G) in ventral view. Thick arrow indicates anterior. Abbreviations: lat.gr, lateral groove; med.gr, medial groove.

Simplified time-scaled phylogeny of the Mawsoniidae with their continental distribution (silhouettes).The trichotomy between three species of Mawsonia (M. tegamensis, M. braziliensis and M. gigas) and between two species of Axelrodichthys (A. araripensis, A. megadromos) and Lualabea are not figured.

Citation: Cavin L, Buffetaut E, Dutour Y, Garcia G, Le Loeuff J, Méchin A, et al. (2020) The last known freshwater coelacanths: New Late Cretaceous mawsoniid remains (Osteichthyes: Actinistia) from Southern France. PLoS ONE 15(6): e0234183. https://doi.org/10.1371/journal.pone.0234183

Editor: Giorgio Carnevale, Università degli Studi di Torino, ITALY

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WFS News: Trackway evidence for large bipedal crocodylomorphs from the Cretaceous of Korea

June 12th, 2020

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@WFS,World Fossil Society,Riffin T Sajeev,Russel T Sajeev

Trackway evidence for large bipedal crocodylomorphs from the Cretaceous of Korea

- Kyung Soo Kim, Martin G. Lockley, Jong Deock Lim, Seul Mi Bae & Anthony Romilio
- Scientific Reports volume 10, Article number: 8680 (2020)
Abstract

Photographs of well-preserved in situ Batrachopus grandis ichnosp. nov. track impressions from surface 2. (A,B) Left pes tracks; (C,D) Right pes tracks. A, C = pes of T7 and T9, respectively. B shows skin impression of heel region (see SI Fig. 5). D = holotype IS 2 of Fig. 6. Photos by J-W K, S-M B and M G L, and compiled in Adobe photoshop (version CS6 88) and Canvas X (version, 20 Build 390, http://www.canvasgfx.com/).

(A) Photograph of the surface from which tracings and 3D images of trackways T16 (the holotype) and T17 of Batrachopus grandis and isolated tracks IS 5-6 were obtained; (B–D) 3D images of pair of tracks including right pes track from holotype trackways T 16; (E) map of the surface shown in A, showing holotype trackway T 16 and paratype trackway T 17. Note well-defined digital pad traces especially in holotype. Photographs, line drawings and 3D images made and compiled by K-S K, M G L and A R. in Adobe Photoshop (version CS6 88) and Canvas X (version, 20 Build 390, http://www.canvasgfx.com/). Compare with Figs. 3–5, SI Figs. 3 and 4 and SI Table 1.

Large well-preserved crocodylomorph tracks from the Lower Cretaceous (? Aptian) Jinju Formation of South Korea, represent the well-known crocodylomorph ichnogenus Batrachopus. The Korean sample includes multiple, narrow-gauge, pes-only trackways with footprint lengths (FL) 18–24 cm, indicating trackmaker body lengths up to ~3.0 m. Surprisingly, the consistent absence of manus tracks in trackways, with well-preserved digital pad and skin traces, argues for bipedal trackmakers, here assigned to Batrachopus grandis ichnosp. nov. No definitive evidence, either from pes-on-manus overprinting or poor track preservation, suggests the trackways where made by quadrupeds that only appear bipedal. This interpretation helps solve previous confusion over interpretation of enigmatic tracks of bipeds from younger (? Albian) Haman Formation sites by showing they are not pterosaurian as previously inferred. Rather, they support the strong consensus that pterosaurs were obligate quadrupeds, not bipeds. Lower Jurassic Batrachopus with foot lengths (FL) in the 2–8 cm range, and Cretaceous Crocodylopodus (FL up to ~9.0 cm) known only from Korea and Spain registered narrow gauge trackways indicating semi-terrestrial/terrestrial quadrupedal gaits. Both ichnogenera, from ichnofamily Batrachopodidae, have been attributed to Protosuchus-like semi-terrestrial crocodylomorphs. The occurrence of bipedal B. grandis ichnosp. nov. is evidence of such adaptations in the Korean Cretaceous.

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WFS News: First Fossil Frog

June 9th, 2020

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@WFS,World Fossil Society,Riffin T Sajeev,Russel T Sajeev

First fossil frog from Antarctica: implications for Eocene high latitude climate conditions

and Gondwanan cosmopolitanism of Australobatrachia

Ilium (NRM-PZ B282) of Calyptocephalella sp. from Seymour Island, Antarctica. Ilium in lateral (a), medial (b), ventral (c) and dorsal (d) views. Magnified region of the dorsal protuberance in lateral (e – dashed rectangle in orange color) and dorsal (f – dashed rectangle in yellow color) view. The dashed line in black on (a) indicates the probable outline of the posterior extension of the ventral acetabular expansion. The asterisk (*) on (a,c) indicates the shallow and broad depression of the ventral acetabular expansion. The double asterisk (**) indicates the notch caudally from the dorsal protuberance. The dashed red lines on (e,f) outline the intact bone surface. Abbreviations: ac, acetabulum; ar, acetabular rim; dae, dorsal acetabular expansion; is, iliac shaft; paf, preacetabular fossa; spf, supraacetabular fossa; vae, ventral acetabular expansion; vd, ventral depression.

Cenozoic ectothermic continental tetrapods (amphibians and reptiles) have not been documented previously from Antarctica, in contrast to all other continents. Here we report a fossil ilium and an ornamented skull bone that can be attributed to the Recent, South American, anuran family Calyptocephalellidae or helmeted frogs, representing the first modern amphibian found in Antarctica. The two bone fragments were recovered in Eocene, approximately 40 million years old, sediments on Seymour Island, Antarctic Peninsula. The record of hyperossified calyptocephalellid frogs outside South America supports Gondwanan cosmopolitanism of the anuran clade Australobatrachia. Our results demonstrate that Eocene freshwater ecosystems in Antarctica provided habitats favourable for ectothermic vertebrates (with mean annual precipitation ≥900 mm, coldest month mean temperature ≥3.75 °C, and warmest month mean temperature ≥13.79 °C), at a time when there were at least ephemeral ice sheets existing on the highlands within the interior of the continent.

3D models of some skeletal elements of Australobatrachia. (a,f) skull and (b–e,g–j) ilia of Calyptocephalella gayi (a–e); Telmatobufo venustus (f–h); Myobatrachus gouldii (i); Limnodynastes convexiusculus (j). Collection numbers of each specimen are listed in Table S1.

Citation: Mörs, T., Reguero, M. & Vasilyan, D. First fossil frog from Antarctica: implications for Eocene high latitude climate conditions and Gondwanan cosmopolitanism of Australobatrachia. Sci Rep 10, 5051 (2020). https://doi.org/10.1038/s41598-020-61973-5

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WFS News: Ectoparasitism and infections in the exoskeletons of large fossil cingulates

May 31st, 2020

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@WFS,World Fossil Society,Riffin T Sajeev,Russel T Sajeev

Ectoparasitism and infections in the exoskeletons of large fossil cingulates

Schematic ilustration and terminologies for the external surface ornamentation of the osteoderms.
(A) and (B), Glyptotherium sp. (C) and (D), Panochthus sp.; (E) and (F), Pachyarmatherium brasiliense. mf: main figure; pf: peripheral figure; cs: central sulcus; rs: radial sulcus; hf: hair follicle. Scale bars: A = 5 cm; B = 4 cm and C = 3 cm.

Studies on paleopathological alterations in fossil vertebrates, including damages caused by infections and ectoparasites, are important because they are potential sources of paleoecological information. Analyzing exoskeleton material (isolated osteoderms, carapace and caudal tube fragments) from fossil cingulates of the Brazilian Quaternary Megafauna, we identified damages that were attributed to attacks by fleas and dermic infections. The former were compatible with alterations produced by one species of flea of the genus Tunga, which generates well-delimited circular perforations with a patterned distribution along the carapace; the latter were attributable to pathogenic microorganisms, likely bacteria or fungi that removed the ornamentation of osteoderms and, in certain cases, generated craters or pittings. Certain bone alterations observed in this study represent the first record of flea attack and pitting in two species of large glyptodonts (Panochthus and Glyptotherium) and in a non-glyptodontid large cingulate (Pachyarmatherium) from the Quaternary of the Brazilian Intertropical Region. These new occurrences widen the geographic distribution of those diseases during the Cenozoic and provide more evidence for the co-evolutionary interaction between cingulates and parasites registered to date only for a small number of other extinct and extant species.

Citation: de Lima FCG, Porpino KdO (2018) Ectoparasitism and infections in the exoskeletons of large fossil cingulates. PLoS ONE 13(10): e0205656. https://doi.org/10.1371/journal.pone.0205656

Editor: Dominique Heymann, Universite de Nantes, FRANCE

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WFS News: First tapejarid pterosaur from the Wessex Formation

May 28th, 2020

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@WFS,World Fossil Society,Riffin T Sajeev,Russel T Sajeev

An isolated, partial premaxilla from the Lower Cretaceous (Barremian) Wessex Formation of Yaverland, Isle of Wight, UK is identified as pterosaurian on account of its overall morphology and thin bone walls. It is regarded as a tapejarid on account of it unique downturned tip with a unique pattern of slit-like foramina on its occlusal surface, while a combination of sensory foramina and lateral outline identify it as a new genus and species, Wightia declivirostris gen. et sp. nov. The downturn of the occlusal margin lies beyond the anterior margin of the nasoantorbital fenestra suggesting affinities with Sinopterus from China rather than South American tapejarids such as Tapejara, Tupandactylus and Caiuajara. This specimen is the first record of Tapejaridae in the Wessex Formation, and is amongst the oldest record of the Tapejaridae outside of China.

The tapejarid’s enlarged crest may have been used for sexual display, researchers said

Source: David M.Martill^a MickGreen^b Roy E.Smith^a Megan L.Jacobs^a JohnWinch^c

^aSchool of the Environment, Geography and Geological Sciences, University of Portsmouth, Burnaby Road, Portsmouth PO1 3QL, UK

^b1 Coastguard Cottages, Military Road, Brighstone, Isle of Wight, PO30 4DA, UK

^cSeajade, 7 West Lake Avenue, Lake, Isle of Wight, POX 36 9NJ, UK

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WFS News: 540m-year-old bug tracks discovered

May 28th, 2020

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@WFS,World Fossil Society,Riffin T Sajeev,Russel T Sajeev

Trackways and burrows excavated in situ from the Shibantan Member.
(A and B) Epirelief (top bedding surface) and hyporelief (bottom bedding surface), respectively. NIGP-166148. Trackways (TW1 and TW2) and undermat burrows (UB1 to UB3) are labeled. (C) Latex mold of (B), with trackways and burrows marked and labeled. (D) Enlargement of rectangle in (B), showing connection between TW2 and UB3 (marked). All photographs were taken with lighting from upper right. Scale bars, 2 cm. Figure produced by Z.C. and S.X. using Adobe Photoshop.

The oldest known footprints on Earth, left by an ancient creepy-crawly more than 500 million years ago, have been discovered in China.

The tracks were left by a primitive ancestor of modern-day insects or worms, according to scientists. Precisely what the creature looked like is a mystery, though: nothing this old with legs has been discovered to date.

Prof Shuhai Xiao, a geobiologist at Virginia Tech University and senior author of the research, said the finding brings scientists closer to understanding what creatures were the first to evolve pairs of legs.

“Animals use their appendages to move around, to build their homes, to fight, to feed, and sometimes to help mate,” he said, adding that the movement of sediments by the first legged creatures could have had a major impact on the Earth’s geochemical cycles and climate. “It is important to know when the first appendages appeared, and in what animals, because this can tell us when and how animals began to change to the Earth in a particular way.”

Previously, scientists had discovered footprints as old as 530-540m years, but none predating the Cambrian period, which also began at this time and marked an explosion in the diversity and complexity of life on Earth. The latest prints date to the Ediacaran period, whose sparse fossil record is populated with soft-tissued creatures including worms and organisms that resembled tiny immobile bags.

The fossils are just a few millimetres in width and Xiao’s team spotted them after painstakingly tilting rock slabs at different angles so the sunlight would illuminate any subtle traces left by ancient bugs.

“The key challenge is to get the lighting right so that the fossils stand out against the background, because the fossils have very low relief,” said Xiao.

On closer analysis, the team found the marks comprise two rows of imprints that they believe were left by a creature scurrying along a riverbed, at a time when life had not yet colonised dry land. The trackways also appear to be connected to burrows, suggesting the creatures periodically tunnelled down into the sediments, perhaps to mine oxygen and microbes as food.

The scientists are unsure whether the creature had many legs or just two, and whether it was a member of the arthropod group, which includes bumblebees and spiders, or annelids, which contains modern-day bristle worms. “Unless the animal died and was preserved next to its footprints,” said Xiao, “it is hard to say who made the footprints.”

The findings are published in the journal Science Advances.

Source: The guardian.com

WFS News: Articulated remains of the extinct shark Ptychodus (Elasmobranchii, Ptychodontidae) from the Upper Cretaceous of Spain

May 27th, 2020

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@WFS,World Fossil Society,Riffin T Sajeev,Russel T Sajeev

In 1996, palaeontologists found skeletal remains of a giant shark at the northern coast of Spain, near the city Santander. Here, the coast comprises meter high limestone walls that were deposited during the Cretaceous period, around 85 million years ago, when dinosaurs still roamed the world. Scientists from the University of Vienna examined this material now and were able to assign the remains to the extinct shark family, Ptychodontidae, a group that was very specious and successful in the Cretaceous but suddenly vanished mysteriously before the infamous end-Cretaceous extinction event.

Shark vertebrae are rare in the fossil record, but precious

Ptychodontid sharks are mainly known from their teeth, which are flattened and allowed them to crush hard-shelled prey, like bivalves or ammonites, similar to some of today’s ray species. However, the find of Spain consists only of parts of the vertebral column and placoid scales (teeth-like scales), which are much rarer than teeth in the fossil record.

Additional articulated (A, B) and disarticulated shark vertebrae (C,D) found in situ associated with EMRG-Chond-SK-1. Picture courtesy of K. Oppermann, 1997. Scale bars equal 20cm (plate A) and 3cm (plates B, C, D).
https://doi.org/10.1371/journal.pone.0231544.g002

In contrast to teeth, shark vertebrae bear important information about a species’ life history, such as size, growth and age, which are saved as growth rings inside the vertebra, like in the stem of trees. Statistical methods and the comparison with extant species, allowed the scientists to decode these data and reconstruct the ecology of this enigmatic shark group.

Ptychodontid sharks grew big and old

“Based on the model, we calculated a size of 4-7m and an age of 30 years for the examined shark. Astonishing about this data is the fact that this shark was not yet mature when it died despite its rather old age.” states Patrick L. Jambura, lead author of the study. Sharks follow an asymptotic growth curve, meaning that they grow constantly until maturation and after that, the growth curve flattens resulting from a reduced growth rate. “However, this shark doesn’t show any signs of flattenings or inflections in the growth profile, meaning that it was not mature, a teenager if you want. This suggests that these sharks even grew much larger (and older)!”

The study suggests that ptychodontid sharks grew very slow, matured very late, but also showed high longevity and reached enormous body sizes. “This might have been a main contributor to their success, but also, eventually, demise.”

Do modern sharks face a similar fate?

Many living sharks, like the whale shark or the great white shark, show very similar life history traits, a combination of low recruitment and late maturation, which makes them vulnerable to anthropogenic threats, like overfishing and pollution.

“It might be the case that similar to today’s sharks, ptychodontid sharks faced changes in their environment, to which they could not adapt quick enough and, ultimately, led to their demise before even dinosaurs went extinct. However, unlike in the Cretaceous period, it is up to us now, to prevent this from happening to modern sharks again and to save the last survivors of this ancient and charismatic group of fishes!”

Source: Science daily

Journal ref:Jambura PL, Kriwet J (2020) Articulated remains of the extinct shark Ptychodus (Elasmobranchii, Ptychodontidae) from the Upper Cretaceous of Spain provide insights into gigantism, growth rate and life history of ptychodontid sharks. PLoS ONE 15(4): e0231544. https://doi.org/10.1371/journal.pone.0231544