Jeff uploaded 3 papers
Jeff uploaded a paper
Jeff uploaded 2 papers
Department Member, Department of Natural Sciences
University of Bristol, Earth Sciences
University of Glasgow, MVLS
Division of Ecology & Evolutionary Biology
Thesis Title: A Fish Fit For Ozymandias?: The Ecology, Growth and Osteology of Leedsichthys (Pachycormidae, Actinopterygii).
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Prof. Colin E. Adams
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About
2012:
The Inside & True Story on the PLoS ONE paper, currently taking the Internet by [grossly inaccurate and lazy journalistic] Ichthyosaur Storm:
http://mrwoodsfossils.blogspot.com/2012/01/missing-skull-bones-hidden-
2011:
Abstract from IV Congreso LatinoAmericano Paleontologia de Vertebrados, San Juan, Argentina, 21-24 September 2011:
THE WORLD'S FIRST CLADE OF GIANT MARINE SUSPENSION-FEEDERS: A PALAEOBIOGEOGRAPHICAL REVIEW OF THE PACHYCORMIFORMES.
Jeff LISTON and Matt FRIEDMAN
Pachycormiformes have traditionally been known from the three major Western European Jurassic fish localities – the Early Jurassic Toarcian of Holzmaden (e.g. Euthynotus Wagner, Pachycormus Agassiz, Saurostomus Agassiz); the Middle Jurassic Callovian of eastern England and north west France (Leedsichthys Woodward, Hypsocormus Wagner); the Upper Jurassic Tithonian of Solnhofen (e.g. Asthenocormus Woodward, Orthocormus Weitzel). There was little to indicate any Cretaceous presence of these animals beyond Protosphyraena Leidy in the USA and England. As such, the palaeogeographic value of Pachycormiformes was, until very recently, regarded as being very low, especially for global perspectives. However, recent reassessments of specimens and new finds have led to an improved awareness of diversity and presence. From a provincial presence of limited taxa, diversities in those same three Western European sources have increased (Ohmdenia Hauff jr. in the Toarcian of Holzmaden, Martillichthys Liston in the Callovian, Pseudoasthenocormus Lambers in the Tithonian of Solnhofen) and previously misidentified specimens from other realms (e.g. Bajocian oolite) have broadened our Jurassic understanding. This has clarified the presence of two large clades within the Pachycormiformes – colloquially referred to as ‘tusked’ and ‘toothless’ – with end-members of barracuda-like predators and whale-like suspension feeders. It has led to some Maastrichtian specimens previously identified as Protosphyraena (‘end-member’ representatives of the tusked Pachycormiformes) to be recognized as part of the edentulous tribe (Bonnerichthys Friedman, Shimada, Martin, Everhart, Liston, Maltese & Triebold), indicating that both of these tribes survived to the end of the Mesozoic era. Further representatives of the toothless tribe have been recognized in the Cretaceous of Western and Central Tethys: a further edentulous specimen, Rhinconichthys Friedman, Shimada, Martin, Everhart, Liston, Maltese & Triebold, has also been found in the Cenomanian, a potentially related taxon in the Albian of southern France, and also in the Turonian of Mexico at Vallecillo. As well as other minor Laurasian presences, Neopachycormus Taverne from the Cenomanian of Burma is likely to be from the tusked tribe.
Gondwanan occurrences of Pachycormiformes have – as is commonly the case with other actinopterygians – been fewer in number and diversity, with nothing reported from India, Africa or Antarctica. Those so far known are of a lost specimen of Pachycormus from the Callovian-Oxfordian of Cerritos Bayos and the edentulous Leedsichthys from the Oxfordian in Antofagasta of Chile, as well as tusked representatives: the reidentified Tithonian Notodectes argentinus Dolgopol de Saez of the black marls of the Neuquén-Mendoza Basin Argentina, an individual from the Aptian of Colombia, and Australopachycormus from the Albian of western Queensland. These last few but important specimens give us the beginnings of a glimpse of the dispersal and vicariance events involved in the spread of Pachycormiformes between Laurasia and Gondwana.
3 Abstracts from MF5 in Mexico:
AN ERA OF SUSPENSE: THE ECOLOGICAL EVIDENCE & MESOZOIC RECORD OF A LINEAGE OF LARGE OSTEICHTHYAN SUSPENSION FEEDERS.
Jeff LISTON1 & Matt FRIEDMAN2
2010, in: González-Rodríguez, K. & Arratia, G. (eds.) Fifth International Meeting on Mesozoic Fishes: Global diversity and Evolution Abstract book and Field Guides, Universidad Autonoma del Estado de Hidalgo, p.62, ISBN: 978-607-482-119-2.
1Division of Environmental & Evolutionary Biology, Faculty of Biomedical and Life Sciences (IBLS), University of Glasgow, Glasgow, G12 8QQ, Scotland; ; 2 Lecturer in Palaeobiology, Department of Earth Sciences, University of Oxford, Parks Road, OX1 3PR, England;
The current ecological niche of large (> 1 metre Standard Length) suspension-feeding marine vertebrate is today dominated by mammals and chondrichthyans. However, fossil evidence suggests that this functional role was dominated by actinopterygians during the Mesozoic era. Prior to the Mesozoic, the largest unequivocal example of an aquatic vertebrate suspension-feeder (as an adult, so excluding juvenile stages of suspension-feeding) was the Carboniferous-Permian acanthodian Acanthodes (SL=40-50cm).
The best known candidate for a large marine suspension feeder in the Mesozoic is the pachycormid Leedsichthys. This genus reached remarkable sizes (SL = 8.9 m) and appears to have been broadly distributed geographically, with remains reported from England, France, Germany and Chile. Apart from Leedsichthys, candidate suspension feeders in the Mesozoic have been limited to putative Cretaceous megachasmid teeth and some Triassic ichthyosaurs, but anatomical evidence for functional interpretations is scant in both cases. In contrast, arguments that Leedsichthys was a suspension feeder derive from multiple aspects of its anatomy: fin arrangement, long, closely-spaced gill rakers, absence of marginal dentition on the oral jaws, a broad gape, and exceptional size. This wide-ranging genus has been recovered from England, France, Germany and Chile. Some have argued that Jurassic trace fossils from Switzerland were made by this fish, and point to iliophagy (i.e. detritus-feeding or sediment sieving) as a not uncommon secondary strategy for suspension-feeders. Several close relatives of Leedsichthys are known, and these might have occupied similar functional roles. Among these is the Jurassic (Kimmeridgian) Asthenocormus, but outstanding questions about the morphology—and, by extension, ecology—of this fish persist despite the collection of several articulated specimens from the lithographic limestones of Solnhofen. More recent work reveals a second probable suspension-feeding pachycormid in the Callovian of England (Martillichthys renwickae) plus additional candidates ranging from the Lower Jurassic (Toarcian) to the Lower Cretaceous (Albian). Thus it appears that far from being a lone actinopterygian experiment in suspension-feeding at large body sizes, Leedsichthys was in fact just one member of a diverse clade of pachycormids occupying this trophic role.
GILL RAKER CHARACTERISTICS AND THEIR VALIDITY AS A TAXONOMIC TOOL: PROBLEMS WITHIN THE PACHYCORMIFORMES
Jeff LISTON
2010, in: González-Rodríguez, K. & Arratia, G. (eds.) Fifth International Meeting on Mesozoic Fishes: Global diversity and Evolution Abstract book and Field Guides, Universidad Autonoma del Estado de Hidalgo, p.61, ISBN: 978-607-482-119-2.
Division of Environmental & Evolutionary Biology, Faculty of Biomedical and Life Sciences (FBLS), University of Glasgow, Glasgow, G12 8QQ, Scotland;
Currently, pachycormiforms are interpreted by some authors as possible stem-group teleosts, and they are therefore important in understanding the phylogeny of advanced actinopterygians. However, the morphology of pachycormiforms is poorly known, a fact that makes any phylogenetic study involving pachycormiforms difficult.
The main goal of this contribution is the study of branchial arches elements in pachycormiforms. Gill rakers (or fanunculi) are elements of the gill skeleton (branchial basket) in fish, that function primarily to protect respiratory lamellae, and sometimes have a secondary role in feeding. Characteristics of gill rakers have been used for taxonomic diagnosis and cladistic analysis of the interrelationships of Pachycormiformes, with particular importance for Leedsichthys and Asthenocormus. The material on which these determinations have been based is reviewed, along with the validity of use of gill rakers in analysis of extinct fish in general, based on their utility in extant fish. Gill rakers are demonstrated to be an unreliable source of taxonomic characters. The assignation of specimen PETMG F34 to Leedsichthys is questionable, but its dissimilarity to recognised specimens of Leedsichthys may be due to its subadult nature. The validity of Leedsichthys notocetes as a distinct species from Leedsichthys problematicus is called into question, as the primary distinction between the two appears based on an artefact structure generated by erosion and fracture.
THE FIRST ?ICHTHYODECTIFORM FROM SCOTLAND.
Jeff LISTON
2010, in: González-Rodríguez, K. & Arratia, G. (eds.) Fifth International Meeting on Mesozoic Fishes: Global diversity and Evolution Abstract book and Field Guides, Universidad Autonoma del Estado de Hidalgo, p.60, ISBN: 978-607-482-119-2.
Division of Environmental & Evolutionary Biology, Faculty of Biomedical and Life Sciences (FBLS), University of Glasgow, Glasgow, G12 8QQ, Scotland;
The disarticulated skull of a large predatory bony fish represents the first osteichthyan component of an otherwise exclusively reptilian (particularly ichthyopterygian) marine fauna from the Upper Kimmeridgian Boulder Bed of Lothbeg Point (58.06278°N, 3.76673°W), south west of Helmsdale, Sutherland, on the north east coast of Scotland. Acid-prepared from a large nodule, the skull was originally identified as an aspidorhynchiform by Patterson. Subsequently, the remaining unprepared nodule was scanned using computerised tomography, to reveal the extent of remaining bony elements within the matrix, and determine whether further preparation was necessary. Although lacking the rear elements of the skull, an extensive set of mandibular, maxillary and palatal elements are present, and can be used as the basis of a tentative diagnosis of ichthyodectiform.
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