John Long

• BSc. Hons, PhD
• Professor at Flinders University

Reproduction in jawed vertebrates (gnathostomes) involves either external or internal fertilization 1 . It is commonly argued that internal fertilization can evolve from external, but not the reverse. Male copu-latory claspers are present in certain placoderms 2–4 , fossil jawed ver-tebrates retrieved as a paraphyletic segment of the gnathostome st...

Newly discovered pelvic and reproductive structures within placoderms, representing some of the most crownward members of the gnathostome stem group and the most basal jawed vertebrates, challenge established ideas on the origin of the pelvic girdle and reproductive complexity. Here we critically review previous descriptions of the pelvic structure...

The transition from jawless to jawed vertebrates (gnathostomes) resulted in the reconfiguration of the muscles and skeleton of the head, including the creation of a separate shoulder girdle with distinct neck muscles. We describe here the only known examples of preserved musculature from placoderms (extinct armored fishes), the phylogenetically mos...

The extinct placoderm fishes were the dominant group of vertebrates throughout the Middle Palaeozoic era, yet controversy about their relationships within the gnathostomes (jawed vertebrates) is partly due to different interpretations of their reproductive biology. Here we document the oldest record of a live-bearing vertebrate in a new ptyctodonti...

Aim: The diversity and distribution of traits in an ecological community determine how it functions. Modern fish communities conserve trait space across similar habitats. However, little is known about trait-space variation through deep time (or across vastly different habitats). In this paper, we sought to identify how trait diversity varies throu...

Well-preserved specimens of a new species of arthrodiran placoderm, Groenlandaspis howittensis sp. nov. (Middle Devonian of Victoria, Australia), reveals previously unknown information on the dermal skeleton, body-shape and dentition of the wide-spread genus Groenlandaspis . The new material includes dual pineal plates, extrascapular plates, and ch...

As part of an Australian Research Council project (The Devonian Gogo Fauna. Diversity, Palaeoecology and Global Significance), which was already granted in 2021 but got delayed due to COVID restrictions and last year’s massive floods that destroyed the bridge at Fitzroy Crossing, we finally were finally able to do the planned field work in the firs...

Well-preserved specimens of an undescribed species of arthrodiran placoderm, Groenlandaspis howittensis sp. nov. (Middle Devonian of Victoria, Australia), reveals previously unknown information on the dermal skeleton, body-shape and tooth arcade of the wide-spread genus Groenlandaspis . The new material includes, dual pineal plates, extrascapular p...

The Late Devonian (Frasnian) Gogo Formation of Western Australia has so far yielded a highly diverse and extremely well-preserved fauna of fishes (> 50 spp.), crustaceans (at least 10 spp. plus ostracods), and conodonts (c. 15 taxa), as well as other invertebrates including nautiloids, goniatites, tentaculitids, conulariids, etc. Research has been...

Memorial to the late Alex Ritchie, Scottish-Australian vertebrate palaeontologist

Four abstracts in the 17th Early/Lower Vertebrates volume are under my authorship: one on Silurian microvertebrates from Scotland and three are memorials for colleagues: Dr Valentina Karatajute-Talimaa (Lithiania), Dr Alex Ritchie (Australia), and Ian Macadie (New Zealand)

Remote Devonian exposures in central Australia have produced significant but highly fragmentary remains of fish-grade tetrapodomorphs. We describe a new tetrapodomorph from the Middle-Late Devonian (Givetian-Frasnian) Harajica Sandstone Member of the Amadeus Basin, Northern Territory, which is represented by several nearly complete skulls along wit...

Jensen et al. (1) question evidence presented of a chambered heart within placoderms, citing its small size and apparently ventral atrium. However, they fail to note the belly-up orientation of the placoderm within one nodule, and the variability of heart morphology within extant taxa. Thus, we remain confident in our interpretation of the minerali...

The origin and early diversification of jawed vertebrates involved major changes to skeletal and soft anatomy. Skeletal transformations can be examined directly by studying fossil stem gnathostomes; however, preservation of soft anatomy is rare. We describe the only known example of a three-dimensionally mineralized heart, thick-walled stomach, and...

The lobe-finned fish, lungfish (Dipnoi, Sarcoptergii), have persisted for ~400 million years from the Devonian Period to present day. The evolution of their dermal skull and dentition is relatively well understood, but this is not the case for the central nervous system. While the brain has poor preservation potential and is not currently known in...

Background The megalichthyids are one of several clades of extinct tetrapodomorph fish that lived throughout the Devonian–Permian periods. They are advanced “osteolepidid-grade” fishes that lived in freshwater swamp and lake environments, with some taxa growing to very large sizes. They bear cosmine-covered bones and a large premaxillary tusk that...

Lungfish (Dipnoi) are lobe-finned fish (Sarcopterygii) that have persisted for over 400 million years from the Devonian Period to present day. They are the extant sister group to tetrapods and thus have the ability to provide unique insight into the condition of the earliest tetrapods as well as their own evolutionary history. The evolution of thei...

The fish-tetrapod transition (which incorporates the related fin-limb and water-land transitions) is celebrated as one of the most important junctions in vertebrate evolution. Sarcopterygian fishes (the “lobe-fins”) are today represented by lungfishes and coelacanths, but during the Paleozoic they were much more diverse. It was some of these sarcop...

Few pre-late Devonian sharks remains are found in Australia and here we discuss new teeth found in Victoria that enable better understanding of early shark teeth including those called Mcmurdodus from Antarctica and Queensland. A new genus and species are named in honour of Dr John Maisey, chondrichthyan specialist.

La paléontologie, l’anatomie comparée, l’embryologie et la biologie moléculaire du développement permettent d’expliquer l’origine évolutive des structures anatomiques constituant le corps humain. Parmi les 213 os qui composent notre squelette adulte, ceux des mains et des doigts ont fait l’objet de nombreuses recherches et de débats depuis plusieur...

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

The evolution of fishes to tetrapods (four-limbed vertebrates) was one of the most important transformations in vertebrate evolution. Hypotheses of tetrapod origins rely heavily on the anatomy of a few tetrapod-like fish fossils from the Middle and Late Devonian period (393–359 million years ago)1. These taxa—known as elpistostegalians—include Pand...

The evolution of fishes to tetrapods (four-limbed vertebrates) was one of the most important transformations in vertebrate evolution. Hypotheses of tetrapod origins rely heavily on the anatomy of a few tetrapod-like fish fossils from the Middle and Late Devonian period (393–359 million years ago)1. These taxa—known as elpistostegalians—include Pand...

Evolution and Development of Fishes - edited by Zerina Johanson January 2019

Evolution and Development of Fishes - edited by Zerina Johanson January 2019

The study of early actinopterygians (ray‐finned fishes) from the Devonian has been hampered by imperfect preservation in the majority of taxa. The Late Devonian (early Frasnian) Gogo Formation of north‐western Western Australia is notable in producing complete fossil actinopterygians with exceptional three‐dimensional preservation of both the derma...

The earliest tetrapodomorph fishes appear in Chinese deposits of Early Devonian age, and by the Middle Devonian they were widespread globally. Evidence for the earliest digitated tetrapods comes from largely uncontested Middle Devonian trackways and Late Devonian body fossils. The East Gondwana Provence (Australasia, Antarctica) fills vital gaps in...

Significant new material of Late Devonian Gogo Formation fish fossils is still surfacing. Collecting in the past decade has uncovered the first Gogo shark fossils ( Gogoselachus plus another new undescribed taxon), the first acanthodian ( Halmacanthodes ahlbergi ), the first coelacanth, as well as the first placoderm embryos. Recent studies have el...

One of the major events in vertebrate evolution involves the transition from jawless (agnathan) to jawed (gnathostome) vertebrates, including a variety of cranial and postcranial innovations. It has long been assumed that characters such as the pelvic girdles and fins, male intromittent organs independent from the pelvic girdles, as well as a regio...

Acid-prepared specimens of the placoderm Brindabellaspis stensioi (Early Devonian of New South Wales, Australia) revealed placoderm endocranial anatomy in unprecedented detail. Brindabellaspis has become a key taxon in discussions of early gnathostome phylogeny, and the question of placoderm monophyly versus paraphyly. The anterior orientation of t...

The skull of 'Ligulalepis' from the Early Devonian of Australia (AM-F101607) has significantly expanded our knowledge of early osteichthyan anatomy, but its phylogenetic position has remained uncertain. We herein describe a second skull of 'Ligulalepis' and present micro-CT data on both specimens to reveal novel anatomical features, including crani...

While environmental factors affect animal locomotion (especially among fliers), few studies have addressed the relationship between aerial function in extinct vertebrates and paleoatmospheric conditions, and none have focused on avian flight. Our study explores the impact of varying O2 concentrations, global temperatures, and air densities on the f...

Australasia has a unique fauna of living vertebrates, which include the oldest known species on the planet (the lungfish Neoceratodus) as well as many diverse, highly endemic families of fish, amphibians, reptiles, birds and mammals. The origin of most of the Australian vertebrate fauna has developed from two phases. Firstly, when Australia was sub...

The phylogeny of early gnathostomes provides an important framework for understanding one of the most significant evolutionary events, the origin and diversification of jawed vertebrates. A series of recent cladistic analyses have suggested that the placoderms, an extinct group of armoured fish, form a paraphyletic group basal to all other jawed ve...

The first virtual cranial endocast of a lungfish from the Early Devonian, Dipnorhynchus sussmilchi, is described. Dipnorhynchus, only the fourth Devonian lungfish for which a near complete cranial endocast is known, is a key taxon for clarifying primitive character states within the group. A ventrally-expanded telencephalic cavity is present in the...

Dinosaurs were once widely considered an evolutionary dead end without much bearing on the evolution of living animals. Yet, today it is clear that theropod dinosaurs gave rise to birds, and that dinosaurs are therefore still alive today. Similarly, placoderms, a group of extinct armored fishes, long held little or no interest to evolutionary biolo...

A series of recent studies recovered consistent phylogenetic scenarios of jawed vertebrates , such as the paraphyly of placoderms with respect to crown gnathostomes, and anti-archs as the sister group of all other jawed vertebrates. However, some of the phylogenetic relationships within the group have remained controversial, such as the positions o...

A ssessing the scientific significance of fossil sites has up to now been largely a matter of subjective opinion with few or no metrics being employed. By applying similar metrics used for assessing academic performance, both qualitative and quantitative, to fossil sites we gain a real indication of their significance that enables direct comparison...

During the evolution of vertebrates, the transition between jawless to jawed vertebrates occurred approximately 425 Ma with morphological and developmental changes. These evolutionary novelties include jaws, paired pelvic fins and endoskeletal girdles, and reproductive intromittent organs. The presence of these novelties in the most phylogeneticall...

Lungfish first appeared in the geological record over 410 million years ago and are the closest living group of fish to the tetrapods. Palaeoneurological investigations into the group show that unlike numerous other fishes—but more similar to those in tetrapods—lungfish appear to have had a close fit between the brain and the cranial cavity that ho...

S1 Fig. Figure showing corresponding endocast landmark points used for registration. A, extant Australian lungfish, Neoceratodus, endocast in dorsal view; B, Late Devonian fossil, Rhinodipterus, endocast in dorsal view. Anterior is to the right.

S2 Table. Table of landmarks used for endocast registration between Neoceratodus to Rhinodipterus. The endocast STL’s were converted into stacks of TIFF slices, from which corresponding landmarks are given as (x,y,z) coordinates from both the exterior surfaces of both endocasts.

The discovery of perfectly preserved 113-119 million year old fossilised hearts in a Brazilian fish Rhacolepis has significant implications for palaeontology and comparative anatomy.

Lungfishes are known for, and indeed take their name from, their bimodal respiratory abilities. All three extant genera can use their lungs to extract oxygen from the atmosphere, although their reliance upon this capability differs among taxa. Lungs are considered primitive for the Osteichthyes, however the distinctive buccal pump mode of air gulpi...

In the pioneering century of Australian geology the ‘BM’ (British Museum (Natural History): now NHMUK) London played a major role in assessing the palaeontology and stratigraphical relations of samples sent across long distances by local men, both professional and amateur. Eighteen-year-old Arthur Woodward (1864–1944) joined the museum in 1882, was...

Selenium (Se) is one of the key trace elements required by all animal and most plant life, and Se deficiencies in the food chain cause pathologies or death. Here we show from new geochemical analyses of trace elements in Phanerozoic marine pyrite that sustained periods of severe Se depletion in the past oceans correlate closely with three major mas...

Availability of nutrients in the ocean can be a major factor affecting bioproductivity, burial of carbon and release of oxygen. However, the nutrient trace element (TE) composition of the palaeo-ocean cannot be measured directly. Here we present a comprehensive global dataset on the TE content of marine sedimentary pyrite in black shales, dating ba...

Background: Living gnathostomes (jawed vertebrates) comprise two divisions, Chondrichthyes (cartilaginous fishes, including euchondrichthyans with prismatic calcified cartilage, and extinct stem chondrichthyans) and Osteichthyes (bony fishes including tetrapods). Most of the early chondrichthyan ('shark') record is based upon isolated teeth, spine...

A new genus and species of selenosteid arthrodire is described from the Late Devonian of Morocco. Driscollaspis pankowskiorum, gen. nov. sp. nov., is defined as a selenosteid with a shallow preorbital plate embayment of the central plate, a paranuchal plate embayment of the central plate as a deep embayment determined by the lateral and posterior l...

Placoderms (stem gnathostomes) preserve the earliest evidence of vertebrate reproductive structures in the fossil record. Newly discovered pelvic and reproductive structures in antiarchs (sister-group of all other gnathosotmes), ptyctodonts and arthrodires (more crownward members of the stem ganthostomes) challenge established ideas on the origin o...

T he evolutionary origin of the intimate act of copulation has been discovered in ancient armoured placoderm fishes called antiarchs. Fossils of the 385 million-year-old antiarch Microbrachius dicki show males with large bony L-shaped claspers for sperm transfer, while females bore small paired bones to help dock the male organs into position. Our...

Many trace elements (TEs) are essential for life. Laser Ablation-Inductively Coupled Plasma Mass Spectrometry (LA-ICPMS) techniques can measure such elements with accuracy down to single parts per billion in pyrite from marine black shale samples. This new dataset of TEs throughout the past 3 billion years reveals trends in TEs in the oceans. Se is...

A diverse vertebrate fauna, comprising both micro-and macrovertebrate remains, is known from the Paleozoic of Western Australia. However, it is the Late Devonian fauna of the Gogo Formation that shows exceptional preservation and which is the best known. Advances in tomographic techniques, both micro-CT and synchrotron, have revealed new histologic...

The ‘buchanosteid’ placoderms are best known from the Early Devonian of Australia, but also occur in China, Russia, Central Asia and the Middle East. Here we rediagnose the type species Buchanosteus confertituberculatus (Hills 1936) from the type locality at Buchan, Victoria, in the light of new material of both head and trunk shields. The superfam...

A small collection of arthrodire remains is described from the Devonian Aztec Siltstone of southern Victoria Land, Antarctica. Barwickosteus antarcticus, gen. et sp. nov., is a small phlyctaeniid arthrodire probably closely related to Barrydalaspis from the Bokkeveld Group of South Africa. Grifftaylor antarcticus, gen. et sp. nov., is a generalised...

The polypterids (bichirs and ropefish) are extant basal actinopterygian (ray-finned) fishes that breathe air and share similarities with extant lobe-finned sarcopterygians (lungfishes and tetrapods) in lung structure. They are also similar to some fossil sarcopterygians, including stem tetrapods, in having large paired openings (spiracles) on top o...

In recent years a number of competing hypothesis have emerged about placoderm relationships (as either monophyletic or paraphyletic) and the interrelationships of the various placoderm clades. Ptyctodontids comprise one of the most specialised clades within the placoderms, characterised by short broad skulls with short median nuchal plates, very la...

According to Graham’s book on air-breathing fishes, osteichthyan (bony) fishes evolved methods of respiring aerially between 39-60 times independently within their evolution. The presence of a lung is inferred as being a characteristic apomorphy defining the group. The early fossil record of osteichthyans shows that the generalised condition was to...

Despite over 50 years of collecting since the Late Devonian 3-D preserved Gogo Formation fish fossils of Western Australia were first studied by the British Museum researchers, significant new material still keeps turning up. The Museum Victoria-AU 2005 and 2008 Gogo Expeditions uncovered the first Gogo shark fossils (two specimens, both new taxa),...

The first articulated phyllolepid placoderm from North America (outside of Greenland) is described from the Upper Devonian Catskill Formation in north-central Pennsylvania. Phyllolepis rossimontina Lane and Cuffey 2005, from the same formation, and the genus Phyllolepis are reviewed based on the new Catskill Formation material and data from a range...

Recent discoveries of advanced fish-like stem-tetrapods (for example, Panderichthys and Tiktaalik) have greatly improved our knowledge of the fin-to-limb transition. However, a paucity of fossil data from primitive finned tetrapods prevents profound understanding of the acquisition sequence of tetrapod characters. Here we report a new stem-tetrapod...

A new tetrapodomorphan fish (Osteichthyes; Sarcopterygii) from the late Middle Devonian (late Givetian) Harajica Sandstone member of the Amadeus Basin, central Australia, is represented by several near complete skulls and much of the body and postcranial skeleton. It has been studied from latex casts made from detailed sandstone impressions. It had...

Although the major features of the evolution of life have shaped the flora and fauna on whichever continent one explores, each has its own peculiarities. These are largely because of differences in each continent’s tectonic and climatic history, coupled with the timing of evolutionary events. So, in its own way, each continent is unique. But of all...

A new acanthodiform acanthodian Halimacanthodes ahlbergi n. gen. n. sp., based on a single uncrushed, partial articulated specimen, represents the first acanthodian collected from the Gogo Formation, Canning Basin, Western Australia. The delicate perichondral ossifications of the lower jaws, branchial skeleton and endoskeletal shoulder girdle are p...

A full description of a complete and articulated, three-dimensionally preserved, placoderm fish, Materpiscis attenboroughi (Ptyctodontida), from the Late Devonian Gogo Formation is presented. The jaw articulation is unique in being preserved in situ, providing new morphological information on the articulation of the quadrate, metapterygoid, and lab...

Since Charles Darwin published his seminal work On the Origin of Species by Means of Natural Selection (Darwin, 1859), museums around the globe have been greatly expanding their holdings of palaeontological collections, and it is estimated that they now hold several hundred million specimens (McNamara and Long, 2007). Most scholars today acknowledg...

177 neosuchian origins and highly unusual palatal conditions, the cranial osteology of a gonio-pholidid has not been fully described. A well-preserved, complete skull of the North American goniopholidid Eutretauranosuchus (AMNH 570) is described. The skull was subjected to CT scans, which revealed a well-preserved palate and braincase. As in Calsoy...

No other continent on Earth has undergone such radical environmental changes as Antarctica. In its transition from rich biodiversity to the barren, cold land of blizzards we see today, Antarctica provides a dramatic case study of how subtle changes in continental positioning can affect living communities, and how rapidly catastrophic changes can co...