Devonian Fish Research Articles

Scottish Middle Devonian fishes in Estonia

A number of Estonian Devonian fishes are shown to be junior synonyms of Scottish species. The Estonian sarcopterygian osteolepid Gyroptychius pauli was originally thought to be closely related to the Scottish species Gyroptychius milleri being differentiated by minor morphological differences of the skull roof. However, here we show that the only skull roof available of G. pauli to the original description (the holotype) was badly damaged in places. This and the fact that skull roofs of osteolepid fishes are morphologically highly variable has allowed us to compare the Estonian and Scottish species and show that G. pauli is a junior synonym of G. milleri . It has also been known for some time that Estonian coccosteid arthrodire Coccosteus orvikui was a junior synonym of the Scottish species Coccosteus cuspidatus . Here we present the evidence for this assumption and also show that the Scottish coccosteid arthrodire Millerosteus minor is almost certainly present in Estonia. Finally, it is shown that the three species have the same stratigraphical distribution in the two regions, strongly indicating a close faunal connection between the Middle Devonian of Estonia and the Middle Devonian Orcadian Basin of Scotland.

Unsuspected functional disparity in Devonian fishes revealed by tooth morphometrics?

The shape of features involved in key biological functions, such as teeth in nutrition, can provide insights into ecological processes even in ancient time, by linking the occupation of the morphological space (disparity) to the occupation of the ecological space. Investigating disparity in radiating groups may provide insights into the ecological diversification underlying evolution of morphological diversity. Actinopterygian fishes initiated their radiation in the Devonian, a period characterized by the diversification of marine ecosystem. Although a former morpho-functional analysis of jaw shape concluded to conservative and poorly diversified morphologies in this early part of their history, fish tooth disparity evidenced here an unsuspected diversity of possible functional significance in the pivotal period of the Late Devonian (Famennian). All teeth being caniniforms, some were stocky and robust, in agreement with expectations for active generalist predators. More surprisingly, elongated teeth also occurred at the beginning of Famennian. Their needle-like shape challenges morpho-functional interpretations by making them fragile in response to bending or torsion. The occurrence of both types of fish teeth during the beginning of the Famennian points to a discrete but real increase in disparity, thus testifying a first burst of feeding specialization despite overall conservative jaw morphology. The disappearance of these needle-like teeth in the Late Famennian might have been related to a relay in dental diversity with abundant co-occurring groups, namely conodonts and chondrichthyans (sharks).

The Devonian placoderm fish Bothriolepis canadensis revisited with three-dimensional digital imagery

The Devonian placoderm fish Bothriolepis canadensis revisited with three-dimensional digital imagery

Early Devonian fishes from coastal De Long Strait, central Chukotka, Arctic Russia

ABSTRACT Calcareous and sandy deposits from the basal members of the Enmakaj and Pil'hikaj formations in coastal exposures along the De Long Strait in central Chukotka, Arctic far-eastern Russia, have yielded two assemblages of fossil fish comprising heterostracan plate fragments, turiniid and other thelodont scales, acanthodian scales and a partial tooth, typical of the Old Red Sandstone facies. Exceptional are acanthothoracid placoderm platelets characteristic of marine facies. In addition a sarcopterygian fragment have been found in Member 1 of the Enmakaj Formation. Some scale surfaces show an unusual, scoured preservation. A Lochkovian age, and most probably basal Lochkovian, is supported for the Enmakaj assemblage, and a somewhat later Lochkovian age is supposed for the Pil'hikaj assemblage. The palaeobiogeographic affinities of these assemblages based on the heterostracans and thelodonts are with other Lochkovian occurrences in Arctic regions such as Severnaya Zemlya, Spitsbergen and the northern a...

Palaeoenvironments of Early Devonian fish and other aquatic fauna of the Campbellton Formation, New Brunswick, Canada

The palaeoecology and palaeoenvironments of the classic fish-bearing strata of the Campbellton Formation are here described. A well-documented fossil assemblage includes acanthodian, placoderm, chondrichthyan, and cephalaspid fishes, tracheophyte remains, eurypterids, ostracods, and molluscs. As part of the Old Red Sandstone continent, the Emsian Campbellton Formation occupied a small basin within the mountainous terrain of the Acadian Orogen, and may have connected through a narrow seaway to a closing foreland basin. The highest diversity of vertebrate fossils was found above a basal unconformity with Val d'Amour Formation volcanics, marked by fissure-fills and unstratified breccia representing a craggy, irregular palaeosurface that provided shelter for some fauna and sediment for rapid burial of skeletal remains. Overlying prodeltaic calcareous siltstones are also highly fossiliferous, and represent a low energy habitat. Occurrences of pterygotid eurypterids, cephalaspids, and chondrichthyans in deltaic sandstones, place these taxa in a habitat that may have been variably fresh or brackish. The surrounding landscape was vegetated with primitive tracheophytes, and abundant plant debris is preserved throughout the basin. The diverse assemblage of fish, arthropods, gastropods, plants and microbial growths suggests that a trophically complex ecosystem was in existence.

The Miguasha Fossil-Fish-Lagerstätte: a consequence of the Devonian land–sea interactions

The evolution of vertebrate assemblages in terms of fluctuating environments has rarely been investigated for the Devonian period. Variation of biodiversity (richness, abundance and species composition) in the diverse Devonian fish assemblage of the Escuminac Formation (Quebec, Canada) is analysed in response to changes in lithofacies, depositional environment and taphonomy through time. Five sequences within an inner wave-dominated estuary show shifts in continentalisation. Although a ubiquitous fish assemblage is identified throughout the formation, species are more diversified and species composition is better structured during relative sea-level rise than during still-stand and relative sea-level fall. Konservat and Konzentrat Fossil- Lagerstatte horizons occur in the transgressive phase of the sequences.

Hugh Miller-geological hero

Hugh Miller was a Victorian geologist and stonemason of humble origins, who did much to further public interest in the new science of geology. His most famous book, The Old Red Sandstone (1841), ran to many editions, and his discoveries of Devonian fossil fishes were of great importance to science. Despite this, he is a relatively unsung geological hero beyond his native land.

The late Middle Devonian fauna of Red Hill I, Nevada, and its paleobiogeographic implications

The fauna of the Middle Devonian Red Hill I locality, Nevada, is unusual in the co-occurrence of a rich fish assemblage with a rich invertebrate one. Sponges are second in abundance of specimens and number of species only to the fishes and occur together with other invertebrates (conodonts, conulariids, dacryoconarid tentaculites, gastropods, bivalves, brachiopods, arthropods, and unidentifiable ammonoids and echinoderms). The invertebrates indicate a marine depositional paleoenvironment. The conodonts indicate a placement within the lower disparalis Zone, late Givetian. The fish assemblage is dominated by the antiarch Asterolepis. All the other fishes, acanthodians, actinopterygians and sarcopterygians, are less common. The closest biogeographic relationship of the fish fauna is with the Middle/Late Devonian fish fauna of the Baltic Region, followed by that of eastern Canada (Miguasha), Scotland and Iran. This distribution corresponds to the Devonian Euramerica faunal province with connection to eastern Gondwana (Iran and Australia). Localities with the same genera as Red Hill I are interpreted as marine with the exception of the Scottish localities. Asterolepis is the most widely distributed vertebrate genus, mostly marine, but it may be able to enter freshwater like Eusthenopteron if one accepts a freshwater depositional paleoenvironment for the Scottish localities. doi:10.1002/mmng.201000001

The late Middle Devonian fauna of Red Hill I, Nevada, and its paleobiogeographic implications

The fauna of the Middle Devonian Red Hill I locality, Nevada, is unusual in the co-occurrence of a rich fish assemblage with a rich invertebrate one. Sponges are second in abundance of specimens and number of species only to the fishes and occur together with other invertebrates (conodonts, conulariids, dacryoconarid tentaculites, gastropods, bivalves, brachiopods, arthropods, and unidentifiable ammonoids and echinoderms). The invertebrates indicate a marine depositional paleoenvironment. The conodonts indicate a placement within the lower <i>disparalis</i> Zone, late Givetian. The fish assemblage is dominated by the antiarch <i>Asterolepis</i>. All the other fishes, acanthodians, actinopterygians and sarcopterygians, are less common. The closest biogeographic relationship of the fish fauna is with the Middle/Late Devonian fish fauna of the Baltic Region, followed by that of eastern Canada (Miguasha), Scotland and Iran. This distribution corresponds to the Devonian Euramerica faunal province with connection to eastern Gondwana (Iran and Australia). Localities with the same genera as Red Hill I are interpreted as marine with the exception of the Scottish localities. <i>Asterolepis</i> is the most widely distributed vertebrate genus, mostly marine, but it may be able to enter freshwater like <i>Eusthenopteron</i> if one accepts a freshwater depositional paleoenvironment for the Scottish localities. <br><br> doi:<a href="http://dx.doi.org/10.1002/mmng.201000001" target="_blank">10.1002/mmng.201000001</a>

Placoderms (Armored Fish): Dominant Vertebrates of the Devonian Period

Placoderms, the most diverse group of Devonian fishes, were globally distributed in all habitable freshwater and marine environments, like teleost fishes in the modern fauna. Their known evolutionary history (Early Silurian–Late Devonian) spanned at least 70 million years. Known diversity (335 genera) will increase when diverse assemblages from new areas are described. Placoderms first occur in the Early Silurian of China, but their diversity remained low until their main evolutionary radiation in the Early Devonian, after which they became the dominant vertebrates of Devonian seas. Most current placoderm data are derived from the second half of the group's evolutionary history, and recent claims that they form a paraphyletic group are based on highly derived Late Devonian forms; 16 shared derived characters are proposed here to support placoderm monophyly. Interrelationships of seven placoderm orders are unresolved because Silurian forms from China are still poorly known. The relationship of placoderms to the two major extant groups of jawed fishes—osteichthyans (bony fishes) and chondrichthyans (cartilaginous sharks, rays, and chimaeras)—remains uncertain, but the detailed preservation of placoderm internal braincase structures provides insights into the ancestral gnathostome (jawed vertebrate) condition. Placoderms provide the most complex morphological and biogeographic data set for the Middle Paleozoic; marked discrepancies in stratigraphic occurrence between different continental regions indicate strongly endemic faunas that were probably constrained by marine barriers until changes in paleogeography permitted range enlargement into new areas. Placoderm distributions in time and space indicate major faunal interchange between Gondwana and Laurussia near the Frasnian-Famennian boundary; closure of the Devonian equatorial ocean is a possible explanation.

The earliest evidence of host–parasite interactions in vertebrates

AbstractTraces of parasite action have been discovered in the Middle–Upper Devonian fish from Estonia, Latvia and European Russia. Such traces are known in heterostracan Psammolepis venyukovi, antiarchs Asterolepis radiata and Bothriolepis ciecere, sarcopterygians Holoptychius sp., Ventalepis ketleriensis and Eusthenodon sp. nov. The traces include evidence of parasitic fixation and penetration as well as dwelling traces. Pathologies are developed as (1) round fossulae on the external surface of bones and scales; (2) oval fossulae with a slight elevation in the centre of the pit; (3) hollow swellings (possible galls); (4) openings (perforations) that have been repaired to various degrees; (5) variously shaped buttresses on the visceral surface of sarcopterygian scales; and (6) porous spongy formations on the non‐overlapped surface of sarcopterygian scales. The round fossulae in sarcopterygian, placoderm and psammosteid skeletal elements could be produced by parasites that are similar to copepod crustaceans. Gall formation in Asterolepis is most likely to be caused by a larva, possibly of a trematode. The perforations of scales (and dermal bones) might arise from the attacks of ectoparasites (copepods?) or different worms. The spongy formations on the Holoptychius scales could be the result of invasion of a unicellular parasite.

Palatoquadrate in a Devonian fish Eusthenopteron Evidence of its dual origin

The palatoquadrate in Eusthenopteron displays certain variation concerning the extent of its commissural lamina, and the presence of imprints of vessels and nerves on the outer surface of this middle part of the element. Comparison with some contemporary fishes revealed that branches of the arteria ophthalmica magna or of the ramus palatinus posterior VII could have produced these imprints. The grooves are connected with canals piercing the bone along its pars pterygoquadrata. Possible explanation is that the autopalatine and pterygoquadrate portions of the palatoquadrate were free in early developmental stages and later become interconnected by cartilage and bone. The dual nature of the palatoquadrate is shown to occur not only in the development of some Recent fishes, but in extinct groups (e. g., placoderms) as well.

Deep time travel

When I read Trewin’s introduction I was intrigued by the story line of time travelling in a bus to study prehistory. It brought to mind the book I used to read to my daughter: The Magic School Bus in the Time of the Dinosaurs by Joanna Cole (1995). After the first few pages it was evident that Trewin has written a book that will very much appeal to the adult reader. He has taken his favourite Scottish fossil localities, built a picture of each landscape and environment at the time the fossils were alive, and brought us on a fact-filled adventure to prehistoric Scotland. We discover the delights of collecting at these classic fossil localities, and are entertained by the sounds, smells and feel of the living fossils from the Devonian to the Jurassic. This book will appeal to the same audience that enjoy Hugh Miller, the famous nineteenth century natural history writer and populariser of palaeontology who wrote The Old Red Sandstone; or,New Walks in an Old Field (1841). Sir Roderick Impey Murchison – the director general of the British Geological Survey in the mid nineteenth century - wrote that Miller’s book “to a beginner, is worth a thousand didactic treatises”. I believe that the same is true of Trewin’s book. Trewin bases his knowledge on facts extracted from publications dating back over 150 years as well as his own researches into the Rhynie Chert, Devonian fishes, as well as Carboniferous, Permian, and Jurassic fossils and palaeoenvironments. It is also apt that Miller and Trewin were both inspired by the fishes of the Devonian Period of the north of Scotland in their pursuit of palaeontological understanding.

J. Long 2006. Swimming in Stone. The Amazing Gogo Fossils of the Kimberley. 320 pp. Fremantle: Fremantle Press. Price A$ 29.95 (paperback). ISBN 9781 921 06433 3.

Swimming in Stone is John Long’s very readable personal account of his encounter with the remarkable fossil fish of Gogo, along with a history of their discovery and their palaeontological importance. Since 1940, forty or so Devonian fish species have been recovered from nodules found around the remote Go Go Station in the Kimberley region of northwestern Western Australia. The carbonate nodules developed in muddy basinal deposits on the seaward side of the extensive tropical barrier reef of the Canning Basin. The nodules developed around the rotting remains of many different kinds of fish but especially armoured placoderms …

Hans-Peter Schultze, a great paleoichthyologist for whom work is synonymous with enjoyment

In the summer of 1982, Hans-Peter Schultze and Gloria Arratia were invited to a small museum located on a fossiliferous site of the Devonian Escuminac Formation in Miguasha, Quebec, eastern Canada, Hans-Peter was to work with Marius Arsenault, the director of the Miguasha Museum, on the skull of the elpistostegalid Elpistostege watsoni, a species closely related to basal tetrapod. In addition, he went through the collections to describe and measure numerous juvenile specimens of the osteolepiform. Eusthenopteran foordi. As expected, there two projects turned out to be important contributions in lower vertebrate paleontology and systematics: one on the origin of tetrapods (1985), and the second one on growth patterns of a Late Devonian fish (1984). During his visit to Miguasha, Hans-Peter also spent time digging for fossils and drawing numerous specimens in the collection. In addition, in order to help the personnel of the museum to identify some of the Escuminac fished, he created an identification key based on the gross morphology of the scales. For a small group of undergraduate students, hired at the museum during the summer as naturalists, it was a unique opportunity to discuss paleontology with a leading researcher. We were amazed by his willingness to talk to us, even if then most of us only spoke French! For the first time, we were exposed to Hennigian methodology and its usage in vertebrate paleontology during and evening lecture that Hans-Peter prepared for us. His lecture was delightful; it was an intensive course in lower vertebrate anatomy, and an intellectual journey among the philosophers Karl Marx and Karl Popper, the entomologists Willy Hennig and Lars Brundin, and "The Band of Four" (Rosen et al., 1981). It was for most of us our first exposure to science, as it should be done. We were all impressed by his knowledge and above all by his simplicity and friendliness. Two years later I started my Ph.D. at The University of Kansas, under the supervision of Hans-Peter. Compared to his long career, these two weeks that Hans-Peter spent in Miguasha represent an extremely shourt period of time. Some might say that this little anecdote is insignificant when introducing a vertebrate paleontologist (Fig. 1A) who published 132 paper and books (a total of 2977 published pages) in addition to more than 80 abstracts, book reviews and obituaries. However, this brief story is representative of Hans-Peter's personality and contributions. He is a great scientist with numerous interests in science, art, and history. Hans-Peter enjoys digging for fossils, looking at fossils and describing fossils, and he loves sharing his knowledge and experiences with people, independent of their academic training. doi:10.1002/mmng.20020050102

A Middle-Late Devonian fish fauna from the Sierra de Perijá, western Venezuela, South America

Abstract. A new Devonian fossil fish fauna from the region of Cano Colorado between the Rio Palmar and Rio Socuy, Sierra de Perija, Venezuela, comes from two localities and several horizons within the Campo Chico Formation, dated on plants and spores as Givetian-Frasnian in age. Placoderms are most common, with the antiarch Bothriolepis perija n. sp., showing affinity with species from the Aztec fish fauna of Victoria Land, Antarctica. A second antiarch, Venezuelepis mingui n.g. n.sp., is also closely related to an Antarctic species, which is reassigned to this new genus. Fragmentary remains of a phyllolepid placoderm show similarity to the genus Austrophyllolepis from southeastern Australia. Chondrichthyan spines are provisionally referred to the Antarctilamnidae, and acanthodian remains include spines of the widespread taxon Machaeracanthus. Osteichthyans are represented by osteolepid and dipnoan scales and teeth, and scales lacking cosmine which may belong to another major taxon. This fauna has provided the first Devonian record from South America of three major fish groups: antiarch and phyllolepid placoderms, and dipnoans. These are widely distributed on most other continents. Although invertebrates and plants from the same sequence closely resemble those of eastern North America, the endemic elements in the fish fauna indicate Gondwana affinities. Phyllolepid placoderms are common in Givetian-Frasnian strata of Australia and Antarctica, but are only known from the Famennian in the Northern Hemisphere. The new phyllolepid occurrence extends their range across the northern margin of Palaeozoic Gondwana. The age and affinities of this new fish fauna are consistent with a model of biotic dispersal between Gondwana and Euramerica at or near the Frasnian-Famennian boundary. A narrow marine barrier separating northern and southern continental landmasses is indicated, in contrast to the wide equatorial ocean for the Late Devonian postulated from palaeomagnetic data. Es wird eine neue devonische Fischfauna aus dem Gebiet zwischen Cano Colorado und Rio Socuy, Sierra de Perija, beschrieben. Die Funde stammen aus zwei Lokalitaten und mehreren Horizonten innerhalb der Campo Chico Formation, die auf Grundlage von Untersuchungen der Pflanzen- und Sporenfunde dem Zeitabschnitt Givetium-Frasnium zugeordnet werden. Placodermen sind durch den Antiarchen Bothriolepis perija n. sp. haufig vertreten. Sie sind mit Arten der Aztec-Fischfauna von Viktoria Land, Antarktis, verwandt. Ein zweiter Antiarche, der Venezuelepis mingui n. g. n. sp. ist eng mit einer Spezies aus der Antarktis verwandt, die ebenfalls dieser neuen Gattung zugeschrieben wird. Fragmentarische Reste eines phyllolepiden Placodermen weisen Ahnlichkeiten mit der Gattung Austrophyllolepis aus dem Sudosten Australiens auf. Wirbel eines Chondrichthyer werden vorlaufig den Antarctilamnidae zugeschrieben. Acanthodir-Reste schliesen das weitverbreitete Taxon Machaeracanthus ein. Osteichthyer sind durch Schuppen und Zahne osteolepider Sarcopterygier und Dipnoi vertreten. Andere Schuppen, denen die Cosminschicht fehlt, gehoren vermutlich zu einem anderen Haupttaxon. Damit ist durch diese Fauna der erste Nachweis fur das Vorkommen der drei Hauptfischgruppen Antiarchi, phyllolepide Placodermi und Dipnoi im Devon Sudamerikas erbracht. Sie sind auch auf den meisten anderen Kontinenten weit verbreitet. Obwohl Invertebraten und Pflanzen aus derselben Zeit sehr denen aus dem Osten Nordamerikas ahneln, weisen die endemischen Elemente in der Fischfauna auf eine Affinitat zu Gondwana hin. Phyllolepide Placodermen sind im Givetium-Frasnianium Australiens verbreitet, aber erst aus dem Famennium in der Nordhemisphere bekannt. Das Auftreten eines neuen Phyllolepiden weitet den Vorkommensbereich uber die nordliche Linie des palaozoischen Gondwanas hinaus aus. Alter und Verwandtschaftsbeziehungen dieser neuen Fischfauna stimmen mit dem Modell der biotischen Verbreitung zwischen Gondwana und Euramerika an bzw. nah an der Frasnium-Famennium-Grenze uberein. Es gibt Hinweise fur eine die nordlichen und sudlichen Landmassen trennende schmale Meerenge. Dies steht im Gegensatz zur Annahme eines weiten aquatorialen Ozeans im spaten Devons, die sich auf palaeomagnetische Daten stutzt. doi: 10.1002/mmng.20020050111

An exceptional Devonian fish from Australia sheds light on tetrapod origins

The transition from fishes to tetrapods was one of the most dramatic events in the evolution of vertebrates, but many pivotal fossils are incomplete, resulting in gaps in the data that are used for phylogenetic reconstruction. Here we present new observations from the most complete, acid-prepared Devonian tetrapodomorph fish yet discovered, Gogonasus, which was previously placed just crownward of Kenichthys and rhizodontids, the most primitive taxa on the tetrapod lineage. Unexpectedly, Gogonasus shows a mosaic of plesiomorphic and derived tetrapod-like features. Whereas the braincase and dermal cranial skeleton exhibit generalized morphologies with respect to Eusthenopteron or Panderichthys, taxa that are traditionally considered to be phyletically close to tetrapods, the presence of a deeply invaginated, wide spiracle, advanced internal spiracular architecture and near-horizontal hyomandibula are specialized features that are absent from Eusthenopteron. Furthermore, the pectoral fin skeleton of Gogonasus shares several features with that of Tiktaalik, the most tetrapod-like fish. A new phylogenetic analysis places Gogonasus crownward of Eusthenopteron as the sister taxon to the Elpistostegalia. Aspects of the basic tetrapod limb skeleton and middle ear architecture can now be traced further back within the tetrapodomorph radiation.

Devonian fish remains, biostratigraphy and unconformities, Narromine 1:250 000 map sheet area, central New South Wales (Lachlan Fold Belt)

A fossil fish assemblage associated with marine invertebrates from the Coonardoo Sandstone (Wallingalair Group) at Boor Hill (eastern limb of Tullamore Syncline) contains phyllolepid and bothriolepid placoderms of probable Late Devonian age. An angular unconformity with the overlying Hervey Group indicates erosion and folding during the Middle – Late Devonian, and evidently younger than the main Tabberabberan orogenic event. Invertebrate remains demonstrate a Late Devonian marine interval, not previously recognised as far west as the Tullamore Syncline, and assumed to represent the global maximum sea-level in the late Frasnian immediately preceding the Frasnian – Famennian extinction event. A phyllolepid placoderm plate from a sedimentary interbed of the Dulladerry Volcanics in the Hervey Syncline compares with abundant phyllolepid material from the Merriganowry Shale Member of the Dulladerry Volcanics near Cowra, and similar occurrences in the Comerong Volcanics and Boyd Volcanic Complex in southeastern New South Wales. Biostratigraphic data suggest a late Middle Devonian (Givetian) age for the Merriganowry Shale Member of the Dulladerry Volcanics, which appears conformable beneath the Upper Devonian Hervey Group.

Swimming with…Devonian fish

Armoured jawless fish, or ‘ostracoderms’, lived 450–360 million years ago, and display unusual morphologies, unlike any modern fish group. Since they left no living descendants, their mode of swimming has, until recently, remained speculative, although this is a crucial question as the first true pectoral fins evolved within the ‘ostracoderms’. The discovery of the oldest‐known fish trails, from the Early Devonian (400 million year old) ‘Lower Old Red Sandstone’ of south‐east Wales offers new insights into the swimming behaviour of these early fish, notably the osteostracan ‘ostracoderms’ (or cephalaspids), whose horseshoe‐shaped head and paddle‐shaped pectoral fins have remained a functional riddle.

Tetrapod-like middle ear architecture in a Devonian fish

Few fossils show the incipient stages of complex morphological transformations. For example, the earliest stages in the remodelling of the spiracular tract and suspensorium (jaw suspension) of osteolepiform fishes into the middle ear of tetrapods have remained elusive. The most primitive known tetrapods show a middle ear architecture that is very different from osteolepiforms such as Eusthenopteron, with little indication of how this transformation took place. Here we present an analysis of tetrapod middle ear origins that is based on a detailed study of Panderichthys, the immediate sister taxon of tetrapods. We show that the spiracular region is radically transformed from osteolepiforms and represents the earliest stages in the origin of the tetrapod middle ear architecture. The posterior palatoquadrate of Panderichthys is completely tetrapod-like and defines a similarly tetrapod-like spiracular tract. The hyomandibula has lost its distal portion, representing a previously unrecognized advance towards a stapes-like morphology. This spiracular specialization suggests that the middle ear of early tetrapods evolved initially as part of a spiracular breathing apparatus.