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Fossil evidence suggests that ray-finned fishes (Actinopterygii) diversified greatly after the largest mass extinction event at the Permian-Triassic boundary. This radiation resulted in a diversity peak in the Middle Triassic, which is manifested in diverse feeding specializations, especially among small-bodied Neopterygii. We present new material from an early Spathian (Early Triassic) outcrop in northern Dobrogea, southeast Romania. The material includes isolated jaw and palatal bones that evidently belong to a single individual, a durophagous actinopterygian, and isolated scales referred to the same taxon. A systematic evaluation of this material indicates affinities with Polzbergiidae, and provides a first glimpse of internal aspects of the feeding apparatus of that group. A pair of ectopterygoids with crushing dentition show a well-developed lateral process, a feature that was previously proposed to be a synapomorphy uniting Cladistia (bichirs) with the Triassic? Scanilepiformes. The recognition of this structure in various Triassic ray-fins (summarized herein) indicates that it was probably widespread among stem neopterygians. The new material belongs to a large individual with a heterodont dentition, therefore representing the earliest large, specialized, durophagous neopterygian. It increases the group's morphological diversity in the Spathian, and hints at an earlier trophic diversification after the mass extinction. Based on new data, we analyse changes in body size of bony fishes through the Early and Middle Triassic. Current evidence suggests that body size distribution remained skewed towards larger sizes in the late Early Triassic, and that the diversification of small-bodied stem neopterygians had not yet been in full swing. [ABSTRACT FROM AUTHOR]

Middle Miocene (Badenian) chondrichthyan fossils collected from the Tekeres Schlieren Member of the Baden Formation at Tekeres (southern Hungary, Mecsek Mts) are described here. The chondrichthyan assemblage is exceptionally diverse and well‐preserved, and consists of holocephalans, selachians and batomorphs. Nine taxa are reported for the first time from the Badenian of the Central Paratethys: Ischyodus sp., Hexanchus cf. nakamurai, Centrophorus sp., Isistius triangulus, Pristiophorus sp., Sphyrna integra, Raja cf. gentili, Dasyatis cf. pastinaca and Mobula fragilis. The fauna is characterized by many deepwater taxa, making it the first bathyal vertebrate assemblage of the Badenian Central Paratethys. However, typically shallow water, littoral forms are also present, which are worn and often broken, indicating that some of the Tekeres fauna was transported and redeposited from a shallow, coastal setting into deeper water environments. Rapid basin deepening and the resulting steep topography can be linked to ongoing rifting of the south‐west Pannonian Basin. The majority of the studied chondrichthyan fauna have extant representatives in the Mediterranean, which supports an active faunal connection between the Mediterranean and the Central Paratethys via the Slovenian Corridor and the existence of a network of deepwater habitats at least along this pathway. [ABSTRACT FROM AUTHOR]

The Early Jurassic Posidonienschiefer Formation in south‐west Germany (Toarcian) records the first appearance of the stem‐teleost group Pachycormidae in the fossil record. However, most pachycormid taxa remain poorly diagnosed or undescribed, making questions of the morphological underpinnings of trophic diversification in the group difficult to address. Here we re‐describe Saurostomus esocinus, a large (≤1710 mm) pelagic pachycormid, based on material from the type formation. Additional material of Saurostomus is identified in near‐coeval strata in Luxembourg, France and the UK, demonstrating a broad European distribution. We assign a neotype, and provide the first formal diagnosis and cranial reconstruction for this genus. Historical misconceptions regarding taxonomic identity of Saurostomus have caused numerous specimens to be conflated with the better known genus Pachycormus. In south‐west Germany, Saurostomus is stratigraphically distributed across the tenuicostatum and serpentinum Zones, encapsulating six ammonite subzones, with an individual from the paltum subzone representing the oldest stratigraphic occurrence of Pachycormidae. Stout recurved teeth, powerful pectoral fins, a streamlined body, a pre‐caudal scaly keel and remnants of coleoid gut contents indicate fast swimming capabilities and a pelagic teuthophagous ecology for Saurostomus esocinus. Cladistic analysis retains Saurostomus as sister to a clade comprising Ohmdenia and the suspension‐feeding pachycormids. Several character states associated with the evolution of suspension‐feeding are shared with Saurostomus, indicating S. esocinus, rather than Ohmdenia, to be the most basal pachycormid to have transitional suspension‐feeding characteristics. The divergence of the suspension‐feeding and macrophagous pachycormids therefore pre‐dates the paltum subzone of the lower Toarcian. [ABSTRACT FROM AUTHOR]

The erection of Orthacanthus buxieri Heyler & Poplin from the lower Permian locality of Buxières‐les‐Mines (Allier, France) was based on a poorly prepared specimen with only a few parts of its anatomy visible. The supposedly related teeth have been regarded as possibly belonging to O. kounoviensis, a species already known from the Carboniferous–Permian of Germany and Czech Republic. The holotype of O. buxieri requires extensive preparation before it can be revised, but the description of Orthacanthus isolated teeth and dorsal spines from Buxières‐les‐Mines nevertheless provides useful information, especially given that no precise description of this material has been provided so far. The aim of this description is to better understand the evolutionary history of the French Orthacanthus and its relationships with the other European species. The studied material is assigned to O. kounoviensis. This is the latest occurrence of this genus in Europe and the presence of both juvenile and adult teeth indicate that Buxières‐les‐Mines was probably one of the last suitable environments for its reproduction. We also identify Orthacanthus cf. kounoviensis from the Muse oil‐shale bed, the first record of this genus in the Autun Basin. This brings into question the relationships between the different Carboniferous–Permian basins of the Northern Massif Central and suggests that they could still have been in connection during the lower Permian, in contrast to the central European basins, which seem to be more isolated from each other. [ABSTRACT FROM AUTHOR]

Freshwater fossil fish faunas have long been used to infer past drainage connections, given that they are bounded by physical freshwater barriers. Here we study a middle Miocene (15.0–15.5 Ma) freshwater fish fossil fauna (Makaraipao) from the Castilletes Formation in northern Colombia, nowadays west of the Andes. We record the presence of lungfishes (Lepidosiren), pacus (Mylossoma and Piaractus), armoured catfishes (Callichthyidae), and red‐tail catfishes (Phractocephalus). Extant members of all those groups (except the Callichthyidae, due to lack of taxonomic resolution) are found in Amazonian faunas east of the Andes and are absent from faunas west of the Andes, indicating that the riverine systems of the Guajira Peninsula were connected to Amazonia during the middle Miocene. The similarity of La Venta (west of the Andes) and Rio Acre (east of the Andes) fish faunas during the late Miocene further indicates that the northern Andean uplift was not a complete barrier at least until c. 11 Ma. However, there is a continental‐wide structuring of the Miocene fish faunas that is also found in the extant faunas, suggesting that other factors such as ecological conditions, in addition to the uplift of the Andes, have shaped the biogeographic evolution of South American fish faunas. [ABSTRACT FROM AUTHOR]

A detailed taxonomic study of a diverse chondrichthyan fauna from the Ladinian–Carnian (Middle–Late Triassic) interval at Nimaigu locality in Guizhou Province, South China is presented. Six taxa are described, two of which are assigned to Elasmobranchii incertae sedis (aff. Rosaodus sp., Rosaodus xingyiensis gen. et sp. nov.) and three to the Euselachii (Euselachii gen. et sp. indet., Favusodus orientalis gen. et sp. nov., Keichouodus nimaiguensis gen. et sp. nov.), while the last one represents a possible Holocephali (aff. Arctacanthus sp.). Their stratigraphic distribution is documented on a bed‐by‐bed basis. This fauna is unusual because it is dominated by sharks with a cladodont‐like dentition (which were barely known after the end‐Permian mass extinction), and because it is almost devoid of durophagous euselachians, which makes it different from all other contemporaneous shark faunas worldwide. Transitional features are documented between 'cladodont' teeth and those of neoselachian sharks, which provide new insights into the replacement pattern of ancient sharks by modern ones. [ABSTRACT FROM AUTHOR]

A new Cenomanian spiny‐rayed fish from El Chango quarry, Chiapas, south‐eastern Mexico is described and included, together with †Zoqueichthys carolinae and †Pepemkay maya, in the most recent phylogenetic analysis of acanthomorph fishes encompassing both extant and extinct taxa. The topologies recovered from the parsimony phylogenetic analysis using both multistate (or composite), and contingent (or reductive), coding are compared, along with a Bayesian estimation. All the analyses corroborate the placement of †Z. carolinae in the Lampripterygii, while both †Choichix alvaradoi gen. et sp. nov. and †P. maya are considered to be incertae sedis members of the Acanthopterygii. Although no apomorphic character states for †C. alvaradoi were found, the unique combination of features supports the description of a new genus and species for the Upper Cretaceous of Mexico. The species herein described is the earliest diverging acanthopterygian lineage. The most outstanding character found is the absence of a true pelvic fin spine, which, together with its placement in the phylogenetic analysis, suggests the independent acquisition of the pelvic fin spine in both paracanthopterygians and acanthopterygians from a segmented first soft ray. This extinct taxon therefore plays an important part in our understanding of both fish diversity through time and the early steps in the diversification of acanthopterygians. [ABSTRACT FROM AUTHOR]

Asteracanthus was one of the most common Mesozoic hybodontiform chondrichthyans, given that remains traditionally referred to this genus have been reported almost worldwide from Middle Triassic to Late Cretaceous strata so far. Asteracanthus was erected by Louis Agassiz for Late Jurassic fin spines with stellate tubercles. Later, Arthur Smith Woodward synonymized Strophodus, originally introduced by Agassiz for distinctive crushing teeth of Triassic–Cretaceous age, with Asteracanthus based on associated teeth and spines from the English Middle Jurassic. This taxonomic scheme has been accepted for more than 130 years until now, although articulated material has never been found. Here, we present a unique hybodontiform skeleton from the German Late Jurassic, displaying a striking combination of characters: tuberculate dorsal fin spines reminiscent of Asteracanthus, and multicuspid teeth that markedly differ from the crushing teeth previously referred to this genus. Using qualitative and quantitative approaches, we compared its fin spines with those that were found in association with Agassiz's Strophodus teeth, providing evidence that Asteracanthus and Strophodus in fact represent two valid genera distinct from all other hybodontiforms. Morphological features that distinguish fin spines of Strophodus from those of all other hybodontiforms include a straight anterior border and distally distributed posterior denticles. These observations led us to present an emended diagnosis for Asteracanthus. Dentally, Asteracanthus shows strong resemblance to Hybodus, but it otherwise lacks a palatobasal process on the palatoquadrate. Therefore, and in the absence of any reliable phylogenetic framework, we recommend treating Asteracanthus as incertae familiae until hybodontiform interrelationships are resolved. [ABSTRACT FROM AUTHOR]

A fossil gastric pellet from the Danian 'Banco Negro Inferior' of the Salamanca Formation at Punta Peligro Locality (Chubut, Argentina) and its 3D preserved fossil content is studied herein. The structure of the pellet and the condition of the enclosed bones suggest that it was produced by a bird of prey, although birds of any kind are as yet unknown from osteological remains in the Banco Negro ecosystem. The content of the pellet originated from a single anuran individual, representing a new species of the genus Calyptocephalella, is described herein as C. sabrosa sp. nov. The new find highlights the broad temporal, geographical and taxonomic diversity of this frog genus in Patagonia's geological past. [ABSTRACT FROM AUTHOR]

Porolepiforms represent a clade of Devonian stem lungfishes, divided into the cosmine‐bearing and probably paraphyletic 'Porolepidae' (e.g. Porolepis, Heimenia) and the cosmine‐free and stratigraphically younger Holoptychiidae (e.g. Holoptychius, Glyptolepis, Laccognathus). Data on the dermoskeleton are available for both groups, but are more limited for 'porolepids'. Here we present new information on the 'porolepid' Durialepis edentatus from the Emsian (Early Devonian) of Germany based on micro‐computed tomography. The material comprises an articulated skull of a single three‐dimensionally preserved individual. The arrangement of the cheekbones of Durialepis edentatus recalls that of Porolepis brevis, with the occurrence of two subsidiary squamosals. However, the parieto‐ethmoidal and postparietal shields are roughly equal in size, a condition similar to that of Glyptolepis groenlandica and intermediate between Porolepis brevis and holoptychiids. A large parasymphysial tooth plate displays five tooth rows with three large tusks in the median row, another intermediate arrangement between the primitive condition of Porolepis sp. (eight rows) and holoptychiids (five or fewer rows). Remarkably among porolepiforms, this dental plate is perfectly symmetrical. Despite the occurrence of cosmine and rhombic scales, the combination of traits displayed in Durialepis deviates from Porolepis in several ways, reflecting features shared with holoptychiids to the exclusion of other 'porolepids'. Durialepis edentatus is thus a key addition to our knowledge of 'porolepid' anatomy. Because Durialepis edentatus preserves much of the cranial and postcranial skeleton in a single individual, it represents a suitable early dipnomorph representative for inclusion in phylogenetic analyses on sarcopterygians and early osteichthyans. [ABSTRACT FROM AUTHOR]

The early Palaeogene represents a key interval in the evolution of modern marine fish faunas. Together with the first appearances of many familiar fish lineages characteristic of contemporary marine environments, early Palaeogene marine deposits worldwide feature the occurrence of osteoglossid bonytongues. Their presence in marine rocks is surprising, given that these fishes are strictly associated with freshwater environments in modern settings and in other parts of the fossil record. Despite its possible relevance to faunal recovery after the Cretaceous–Palaeogene (K–Pg) extinction, this marine osteoglossid radiation is relatively understudied. Here we describe an osteoglossid specimen from marine Danian deposits of western Greenland (Eqalulik Formation, northern Nuussuaq Peninsula). It consists of disarticulated cranial, pectoral and vertebral material belonging to a relatively large‐bodied predator, similar to the widespread †Brychaetus but with some distinctive features. This specimen expands the geographical range of extinct osteoglossids to the Arctic and represents one of the earliest records of this group in marine deposits. We review other fossil occurrences of marine osteoglossids, highlighting temporal and biogeographical patterns that characterize their rise, diversification and sudden disappearance in the middle Eocene. It is likely that the transition from freshwater to marine environments occurred around the K–Pg boundary, possibly related to ecological replacement of predatory fish lineages that went extinct at the end of the Cretaceous. Further study of the Eqalulik Formation fauna could yield additional insight into the consequences of the end‐Cretaceous extinction with regard to marine fish evolution and the assembly of modern marine faunas. [ABSTRACT FROM AUTHOR]

A new fossil batoid (ray) Ptychotrygon rostrispatula sp. nov. is described from five exceptionally well‐preserved, three‐dimensional skeletal remains from the Turonian (Late Cretaceous) of Morocco. These specimens represent the first known skeletal remains for the genus Ptychotrygon and allow an almost complete description of the genus, providing a new insight into its phylogenetic relations and validating its taxonomic status as a member of the Sclerorhynchoidei. Mechanical preparation of the fossil remains revealed a relatively large batoid species (estimated total length above 1 m). Overall the morphology resembles that of sclerorhynchoids, with a robust hypertrophied rostrum that lacks enlarged rostral denticles with enlarged paddle‐like pectoral proximal elements (propterygium, mesopterygium and metapterygium). Never before seen details of the branchial skeleton are presented (large second hypobranchial without anterior process, which was probably fused to the basibranchial and no evidence of articulation with other branchial element). To assess the phylogenetic relations of these specimens within the sclerorhynchoids a parsimonious analysis using TNT and PAUP was performed. These analyses included Asflapristis cristadentis and Ptychotrygon rostrispatula sp. nov., which were used as representatives of Ptychotrygonidae, and also includes six other genera of sclerorhynchoids with relatively good skeletal remains. Both analyses recovered two monophyletic groups within sclerorhynchoids: the first contains Ischyrhiza, Onchopristis and Schizorhiza, and a second that includes Micropristis, Sclerorhynchus, Libanopristis and Ptychotrygonidae. [ABSTRACT FROM AUTHOR]

Our understanding of the ecology and phylogenetic relationships of Pachycormiformes, a group of Mesozoic stem teleosts including the iconic Leedsichthys, has often been hindered by a lack of comprehensive morphological information. Micro‐CT scanning of an articulated, although flattened, cranium of the edentulous Martillichthys renwickae from the Middle Jurassic (Callovian) Oxford Clay of the UK reveals previously unknown internal details of the most complete suspension‐feeding pachycormiform skull known, including the palate, braincase and branchial skeleton. The latter preserves gill rakers with elongate, pointed projections similar to those of Asthenocormus, in contrast to the finer fimbriations associated with Leedsichthys. We also reinterpret some previously described features, including dermal bone patterns of the snout, skull roof and lower jaw, and the morphology of the ventral hyoid arch. These new anatomical data reinforce the phylogenetic placement of Martillichthys as part of the Jurassic clade of edentulous pachycormiforms. The elongate skull geometry of these Jurassic taxa is strikingly similar to that of Ohmdenia, the sister taxon to edentulous pachycormiforms, but contrasts sharply with the morphology of the Late Cretaceous edentulous pachycormiform Bonnerichthys, raising questions over the phylogenetic relationships among these taxa. Most significantly, Martillichthys shows specialized characters with a restricted phylogenetic distribution among suspension‐feeding pachycormiforms, including the distinctive gill rakers and a greatly extended occipital stalk. Our analysis of Martillichthys supports past interpretations of a close relationship with Asthenocormus, and provides a model for interpreting the less complete remains of other members of this enigmatic group of fishes. [ABSTRACT FROM AUTHOR]

The evolution of modern sharks, skates and rays (Elasmobranchii) is largely enigmatic due to their possession of a labile cartilaginous skeleton; consequently, taxonomic assignment often depends on isolated teeth. Bullhead sharks (Heterodontiformes) are a group of basal neoselachians, thus their remains and relationships are integral to understanding elasmobranch evolution. Herein we fully describe †Paracestracion danieli – a bullhead shark from the Late Jurassic plattenkalks of Eichstätt, Germany (150–154 Ma) – for its inclusion in cladistic analysis (utilizing parsimonious principles) of morphological characters from complete †Paracestracion and Heterodontus fossil specimens as well as extant forms of the latter. The presence of two separate monophyletic clades within Heterodontiformes was confirmed, based on predominantly non‐dental characters, which show a strong divergence in body morphology between †Paracestracion and Heterodontus; the latter possessing a first dorsal fin and pectoral fins that are more anterior and pelvic fins that are more posterior. This study emphasizes the importance of including non‐dental features in heterodontiform systematics (as compared with the use of dental characters alone) and supports the erection of the family †Paracestracionidae. Further, phylogenetic analysis of molecular data from five extant species suggests that crown heterodontiforms arose from a diversification event 42.58 Ma off the west coast of the Americas. [ABSTRACT FROM AUTHOR]

A new double‐armoured herring of the clupeomorph order Ellimmichthyiformes, Eoellimmichthys superstes gen. et sp. nov., is described herein based on a single partially complete specimen from the early Eocene Pesciara site of the Bolca Konservat‐Lagerstätte, north‐eastern Italy. The fossil documented herein exhibits a unique combination of features (e.g. ornamentation of the skull bones; medial fusion of the contralateral halves of the neural arches of abdominal vertebrae; teeth on endopterygoid, parhypural fused to the first preural centrum; presence of a short series of 6 (or 7) predorsal scutes increasing in size posteriorly; postpelvic scutes bearing very prominent spines), which clearly supports its recognition as a new genus and species of the family Paraclupeidae. Evidence is provided to show that Eoellimmichthys gen. nov. is most closely related phylogenetically to the Early Cretaceous genus Ellimmichthys. The new taxon described herein represents the youngest marine occurrence of the family Paraclupeidae and, more generally, of the order Ellimmichthyiformes, suggesting that the shallow marine settings of the Tethys might have favoured the persistence of certain fish lineages that were severely affected by the end‐Cretaceous mass extinction. [ABSTRACT FROM AUTHOR]