Liston, J.J.

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<i>Leedsichthys</i> des Vaches Noires...au peigne fin

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       Liston, J.J. (2008) Leedsichthysdes Vaches Noires...au peigne fin. L'Écho des Falaises, 12 . pp. 41-50. ISSN 1253-6946  http://eprints.gla.ac.uk/58380/  Deposited on: 12 December 2011   Enlighten – Research publications by members of the University of Glasgow http://eprints.gla.ac.uk TITLE The fine comb of the Vaches Noire Leedsichthys ?  A r generations, and acanusthpr W ny fish Leedsichthys, I was aware that some of its remains lay in private collections. After all, the original type material had been collected pronbrMMbohodi‘pstunanSc Leit pa ved (LISTON, 2004) – for example, no vertebral centra have been ossified for Le rait that is not unusual within its family, Pachycormidae (LAMBERS, 1992). It ha meant that the clusters of isolated bones from it that are found are often misidentified. Over thbe19 s a researcher, you know the value of collections. Material built up ovecumulated within venerable institutions – always cited and figured, and used as the basis for y state-funded research project. But the role of the private collection is a different one. It is ually acquired through the zeal and tenacity of an individual, without external funding, just eir own drive to collect material from a particular locality – sometimes regardless of the evailing weather conditions. hen I came to research the Jurassic boivately, by Alfred Nicholson LEEDS, in the 1880s (SMITH WOODWARD, 1889a). It was e of many animals new to science that he discovered while gathering bones from the many ick pits opened to excavate the Callovian Oxford Clay around Peterborough (LEEDS, 1956). ostly marine reptiles, many of those animals were named after him by CW ANDREWS (e.g. uraenosaurus leedsi, Steneosaurus leedsi), once Leeds’ collection had become known to (and ught by) the British Museum (Natural History) in London (ANDREWS, 1910 ; 1913). But the nour of having a genus named after him was reserved for the extremely large bony fish that he scovered - Leedsichthys (SMITH WOODWARD 1889b) – a suspension-feeding rototype’/forerunner of today’s basking shark and whale shark. Some may remember that this unning animal’s giant 2.74 metres high tail (FIGURE 1) was mounted in the British Museum til 1987. But since then, no remains of Leedsichthys have been on public display in a museum ywhere in the world, apart from the Hunterian Museum in the University of Glasgow, otland. edsichthys is a patchy fossil. This is because its skeleton was sparsely ossified, in other words largely remained cartilage instead of changing into bone as the animal aged, and so it is only rtially preseredsichthys, a ts e years, this has resulted in different bones from Leedsichthys being incorrectly identified as longing to a stegosaurian dinosaur on three separate occasions (HULKE, 1887 ; HUENE, 01 ; MICHELIS et al., 1996). Of the parts of Leedsichthys skeleton that did change from cartilage into bone, many of them cotamsubebonpafrth(S W h a strategy of restricted ossification of the skeleton? These become clear when one starts to consider the questions of size associated with Le dsichthys. Different adult specimens of Leedsichthys have been estimated to have lengths rarayelainAlthlabrosthth WhyFoelco behaviour in contemporary fish, enabling them to su ension-feed on plankton in the water column, as well as filtering the sediment on the sea-bontained very limited amounts of bone, with significant resorption of the internal compact bone king place, often leaving the bones as thin shells or cases, surrounding a largely hollow spongy ass. This means that in bones such as the hyomandibula and parietal, the weight of the rrounding sediment over time has caused the internal spongy bone to collapse, and the bone to  crushed flat. This often leaves the outer shell of the bone fragmented into thin platey shards of e, with external and internal faces of a bone compressed into tight apposition. Thus even rtial remains of the animal will consist not of hundreds, but thousands of parts, consisting of agments of different layers of different bones, all mixed together. This is one of the reasons that e bones of this animal have remained largely unidentified since its first description in 1889 MITH WOODWARD, 1889b). hat would be the possible benefits of sucenging from 7-12 metres in length. Growth ring analysis (LISTON et al., 2005) indicates ages nging from 17 to 31 years, respectively. One specimen, with a calculated age of around 45 ars, is likely to be the largest individual of Leedsichthys ever discovered, with some of the rgest bones known and an estimated size of up to 16.5 metres (LISTON, 2007). These figures dicate a bony fish that lived to large adult sizes, and this would mean a significant body mass. ough weight is less apparent in the aquatic environment, it has significant implications for rge animals, which will face problems of constraints on their manoeuverability, in terms of aking, accelerating, turning and sinking. Constraining the proportion of the skeleton that sifies restricts the skeleton’s density and therefore the fish’s overall body mass. This means at controlling the ossification of the skeleton can help a large animal to travel with less effort rough the water column.   is it believed that this fish was a suspension-feeder? For one thing, it is utterly toothless. r another, a 1.5 metre long gill basket of this fish has been recovered, lined with a series of aborate gill rakers (FIGURE 2). Such gill rakers, in conjunction with toothlessness, are closely rrelated with suspension-feeding spttom, as mammals like grey whales do today (HANS NELSON & JOHNSON, 1987 ; HANS NELSON et al., 1987). So the specific structure of the gill rakers might well give us important in A has been noted, the Oxford Clay in England has been the major producer of the remains of thbewoB‘bofWafitsrak In(F  that he had found a co centration of pterosaur lower jaws when he came across the remains in the Atacama Desert of Chi+ 7so(slothsostelehethre I paformation on the feeding patterns of this animal. s is fish. In addition, it is also found in northern Germany, the Atacama Desert of Chile, and the aches around Normandie (FIGURE 3). From this last locality, it is exclusively known from the rk of private collectors (BUFFETAUT, 1983). In 1857, M’sieu TESSON of Caen sold the ritish Museum (Natural History) a block of gill rakers (FIGURE 4), identified as the ranchiostegous rays’of a fish, from the Vaches Noires. For over ninety years, the only element  Leedsichthys that was figured in the scientific literature were its gill rakers (SMITH OODWARD, 1890). Today, the gill rakers of this animal have become a key area of research: ter all, if this was the largest bony fish of all time, and it managed to grow so large because of  ability to effectively extract nutrition from the water column, then what was it about its gill ers, that made it so good at suspension-feeding?   Leedsichthys, the gill rakers resemble small 7.5cm long jaws with an upper serrated edge IGURE 5), leading MARTILL (pers. comm.) to briefly believenhile in the late nineties (MARTILL et al., 1999). In detail, the blocks from the Atacama show nts of a further, finer texture associated with the gill rakers – fragments of a mesh (FIGURE 6 ). Although the English Oxford Clay invariably washes easily from the specimens, this ftness of matrix also means that it does not support or preserve the fine structures visible in the lightly younger Oxfordian) Atacama Desert specimens. In contrast, the matrix from the Chilean cality is very hard, but although it preserves the more fragile structures, it is difficult to prepare is material away from this delicate structure without damaging it. Acid-etching starts to reveal me laminae attached to the upper surface of the gill rakers, but even consolidating these ructures with Butvar consolidant as they emerge in the acid does not support these fragile ments once more than 2mm of laminar height has been etched from the matrix. State of the art lical CT-scanning has been used at Glasgow’s Vale of Leven hospital to try and reveal the ree dimensional structure contained within the rock, but it was unable to give the necessary solution of these fine structures.  had come across references to the Leedsichthys material of CHARLES and PENNETIER in a per published by Nathalie BARDET in 1993, and I knew that if those collectors had allowed researchers access to their collections before, then they might well do so again (BARDET et al., 19mPEsubewacofust Tm rial shed some new light on the question of the delicate structures associated with gill rakGfrFrlaan The agst hat the re archer needs. This has meant that some exceptional reptile specimens (in particular the skull ofthpaorthcora Tfro93). In 1993, Bardet’s paper had reported the first histological analysis of Leedsichthys aterial, based entirely on ceratobranchial specimens in the collections of CHARLES and NNETIER. The ceratobranchials are the core component of the fish’s gill skeleton, in life pporting the gill lamellae that allow the gas exchange necessary for the fish to respire, and aring soft tissue to which the gill rakers were attached. These gill rakers sat in the flow of ter entering the mouth of the fish, so that nutrient particles (for example, zooplankton such as pepods) would be trapped by them, and redirected towards the fish’s gullet. The presence of a rther mesh structure sitting on top of the serrated edge of the gill raker hints at an advanced ructure for extracting nutrients not previously seen in contemporary or fossil fish.  he German ‘ornatenton’ Leedsichthys material does not contain gill rakers. Could the French ateers? Via the Association Paleontologique and the much-appreciated assistance of Jean Marie UEGAN, I finally managed to get in touch with Gérard and arranged to meet him with a good iend of mine from Paris, who had kindly offered to act as a translator for me (as, sadly, my ench evening classes did not provide me with any lasting availability in this beautiful nguage). In, 2004 we arrived at the Pennetiers’ Parisian domicile, the home of their collection, d I examined the material that they had collected over the years. lithology that contained the Pennetier’s specimens was indeed different – although the same e as the English Oxford Clay, it acts as a thicker clay matrix, that supports and protects fine ructures without being impregnable to the tools of the preparator – in short, just wse a steneosaur) have been recovered and prepared by Elizabeth and Gérard PENNETIER over e years. For the specimens of Leedsichthys gill rakers, it was a revelation. One specimen in rticular emerged from a nodule, showing its delicate transverse laminae, that seemed to iginate just beyond the external gill raker surface before crossing to the matching position on e opposite side of the raker (FIGURE 8). The gill rakers had these delicate planar transverse nnections between each side, and possessed a median septum running down the length of the ker. Nothing like this had been seen before for these – or other – fish. hese findings were further supported by remains recovered by private collector Dolf GIELEN m the younger Kimmeridgian age clay of Cap de la Heve in early 2004 (FIGURE 9) (LISTON, in press). In addition to a series of fin rays, an immaculately-preserved gill raker in his coAuncorapos Si ta gathering in November 2004, software has become available that can m ely discriminate between the delicate structures within the scan images and the suglcoimacoac Ane rivate collectors – before any su  work can be done.  AMan  Dolf GIELEN, for giving me access to their remarkable fossil co ections.  Also to the tireless patience of J.-M. GUEGAN, who facilitated the first contact be ReAA f the marine reptiles of the Oxford Clay. Volume 2.  British  BA , N.; PENNETIER, E.; PENNETIER, G.; CHARLES A. & CHARLES J. (1993) - Des os énigmatiques à gulaire dans le Jurassique Moyen (Callovien) de Normandie. Bulletin Trimestriel de la Societé  de Normandie et des Amis du Muséum du Havre 80: 7-10. Bull. Trim. Soc. Géol. Normandie et llection (also based in Paris) confirmed the oblique transverse laminae crossing the gill raker. lthough these gill raker specimens greatly improve our knowledge of the appearance of damaged gill rakers of Leedsichthys, as opposed to the denuded thousands of gill rakers llected from the English Callovian, they only provide a base for the mesh fragments to sit on, ther than a full three dimensional understanding of the extent of the mesh, and thereby its sible function. nce the original CT daore effectivrrounding interference patterns from the matrix.  Armed with the morphological knowledge eaned from individual specimens gathered from the beaches of northern France in the llections of PENNETIER and GIELEN, we can hope to use this in conjunction with the scan ges to produce a 3D model of a cluster of gill rakers.  This model can then be extended to ver the whole of the 1.5 metre long gill basket, in order to assess its likely hydrodynamic tivity during Leedsichthys swimming and feeding. lthough technology offers many ways forward in extracting data from fossil material, one still eds the high quality fossil specimens – invariably gathered by pchCKNOWLEDGEMENTS y translators, Marie-Céline BUCHY and Jean-Luc PEART, as well as the collectors, Gérard d Elisabeth PENNETIER andlltween myself and the Pennetier. ferences NDREWS C.W. (1910) - A descriptive catalogue of the marine reptiles of the Oxford Clay. Volume 1. British Museum (Natural History), London, pp 1-205. NDREWS C.W .(1913) - A descriptive catalogue oMuseum (Natural History), London, pp 1-206. RDETsection trianGéologiqueAmis Muséum du Havre. BUFFETAUT, E. (1983) - La paléontologie des vertébrés Mésozoïques en Normandie du 18e siècle à nos jours: Un HANS NELS  the sea floor. Scientific American HANS NELS SON, K.R. & BARBER JR., J.H. (1987) - Gray whale and walrus feeding excavation on the Bering Shelf, Alaska. Journal of Sedimentary Petrology 57: 419-430.  HUEHLAGer LELI TON, J.J In: ARRATIA, G. & TINTORI, A. (eds) Mesozoic Fishes 3 - Systematics, Paleoenvironments and Biodiversity. Verlag Dr. Friedrich Pfeil, München. LISTON J.J. (2007) - A Fish Fit For Ozymandias?: The Ecology, Growth and Osteology of LISTON J.J. LI s.  - In: cs, Homology and Nomen MMICHELIS, REITKREUZ, H. (1996) - Die Vertebratenfauna des Callov r (Wallücke, Wiehengebirge).  [The Callovian (Middle SMITH WO SMITH WOODWARD, A. (1889b) - Preliminary notes on some new and little-known British Jurassic fishes.  —  essai historique. Actes du Muséum de Rouen 1983: 39-59. ON C. & JOHNSON K.R. (1987) - Whales and walruses as tillers of256: 74-81. ON, C, JOHNNE, F. v. (1901) - Notizen aus dem Woodwardian-Museum in Cambridge. — Centralbl. Min. Geol. Pal.: 715-719. ULKE, J.W. (1887) - Note on some Dinosaurian remains in the collection of A. Leeds Esq., of Eyebury, Northamptonshire.  — Quart. Jour. Geol. Soc.London 43: 695. MBERS, P.H. (1992) - On the Ichthyofauna of the Solnhofen Lithographic Limestone (Upper Jurassic, many). - Proefschrift Rijksuniversiteit Groningen: 1-336.  EDS, E.T. (1956): The Leeds Collection of Fossil Reptiles. 104 pp.  Oxford. . (2004) - An overview of the pachycormiform Leedsichthys; pp 379-390. SLeedsichthys(Pachycormidae, Actinopterygii).  PhD Thesis. 464 pages.   (in press) - The Occurrence Of The Middle Jurassic Pachycormid Fish Leedsichthys. Oryctos. STON J.J., STEEL, L., & CHALLANDS, T.J. (2005) - Lured by the Rings: Growth structures in LeedsichthyPoyato-Ariza, F. J. (ed.): Fourth International Meeting on Mesozoic Fishes - Systematiclature, Ext. Abstr.: 147-149. ARTILL, D. M., FREY, E., CACERAS, R.P. & DIAZ, G.C. (1999) - The giant pachycormid Leedsichthys (Actinopterygii) in the southern hemisphere: further evidence for a Jurassic Atlanto-Pacific marine faunal province. —  N. Jb. Geol. Palaont. Mh. H 243.  I., MARTIN SANDER, P., METZDORF, R. & Biums (Mittlerer Jura) aus dem Steinbruch StörmeJurassic) vertebrate fauna of the Störmer Quarry (Wallücke, Wiehengebirge).].  Geol. Palaont. Westf. 44: 5. ODWARD, A. (1889a) - On the palaeontology of sturgeons. —  Proc. Geol. Assoc. London 11: 24-44. Geol. Mag., Dec. III 6: 448-455. SMITH WOODWARD, A. (1890b) - Note on the gill-rakers of Leedsia problematica - a gigantic fish from the Oxford   FIThe 2.74 me n display in the British Museum (Natural History), London, in Sebackdr  FIClay.  — Geol. Mag., Dec. III 7: 292-293. GURE 1 tre high tail specimen BMNH P 10000 optember 1937.  Peripheral skeletal components not recovered from the site have been added as a painted op.  © The Natural History Museum, London. GURE 2  Comment [MSOwhere's 'a'? ffice1]:  The 1.54 metre high gill basket of BMNH P.10156 on display in the fossil fish gallery of the British Museum (Nca FIGURE 3  M an localities where Leedsichthys remains have been uncovered. C = Cap de la Hève; CM = Ch erg P = Peterborough; V = Villers-sur-mer; W = Wiehengebirge.  FISpecimen BMNH 32581, a concretion of disarticulated gill rakers from Vaches Noires, the earliest-collected sp thys, sold by Tesson of Caen to Richard Owen of the British Museum (Natural History) in 18 FILaW th of block in field of view = 129mm.  FIA NK2573.PAL), with plan view of fragment, showing ‘mesh’ etched from surface of limestone matrix, cross-linking from gill raker to gill raker.  Fragment = 40mm wide.  FIOuIn FIG vian of Normandie, Collection Pennetier.  Lateral view showing oblique edges forming tra  FIGURE 8b Gill raker from Callovian of Normandie, Collection Pennetier.  Plan view of gill raker, showing median septum. D  raker ends = 60mm.   FIGill raker from Upper Kimmeridgian of Cap de la Hève.  Length = 83mm, Photograph courtesy of D. Gielen.    atural History) in 1924. Image supplied by Alison Longbottom, NHM (London).  300mm ruler sits in bottom of se for scale.  Each branchial arch is flanked by stacks of gill rakers, all preserved in one large concretion. ap showing Europeristian Malford; L = LiesbGURE 4  ecimen of Leedsich57.  This specimen was included in Smith Woodward’s 1889 type description.  Scale bar = 50mm. GURE 5  teral view of gill raker in specimen BMNH 32581 (see FIGURE 4), from the Callovian of the Vaches Noires.  idGURE 6  cid-etched fragment from Atacama Desert block (SMGURE 7  tline drawing overlying thin-sections of fragment from SMNK 2573.PAL block, from ‘plan view perspective’  terraker gap (distance from centre of gill raker stalk to adjacent centre of gill raker stalk) = 19mm.   GURE 8a  ill raker from Callonsverse planes across the gill raker.  Length of gill raker visible = 20mm. istance between gillGURE 9  

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<i>Leedsichthys</i> des Vaches Noires...au peigne fin

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