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19 pages, 19774 KiB

Open AccessArticle

Living Taxa and Their Importance in Understanding the Extinct Diversity: A Look at Polypterid Pinnules

by Marcos Vinícius Coelho, Camila Cupello, Paulo M. Brito and Olga Otero

Diversity 2023, 15(4), 517; https://doi.org/10.3390/d15040517 - 03 Apr 2023

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Pinnules are the peculiar, impaired spines that carry each of the numerous finlets that constitute the dorsal fins of polypterid fishes (Cladistia and Polypteriformes). Previous studies, including a recent detailed paper on the comparative analysis of the morphology of pinnules in most of [...] Read more.

Pinnules are the peculiar, impaired spines that carry each of the numerous finlets that constitute the dorsal fins of polypterid fishes (Cladistia and Polypteriformes). Previous studies, including a recent detailed paper on the comparative analysis of the morphology of pinnules in most of the extant species (genera Polypterus and Erpetoichthys), suggest that they display unique characteristics that allow for species identification. Since most of the polypterid fossil records are composed of scales that lack specific characteristics and isolated pinnules, this work aims to test their taxonomic relevance before comparing the fossil pinnule morphologies across the fossil records in order to evaluate polypterid paleodiversity. Therefore, we describe the intra-individual and intra-specific morphological variations of the pinnules in the extant species Polypterus bichir. Furthermore, we compared it with the various morphologies described in the Polypteridae family. We report intra-individual variability related to the anteroposterior axis of the dorsal fin. We also report morphological differences in the pinnules among specimens that overlap those anticipated among different species, concluding that the pinnule morphology cannot support taxonomic purposes in polypterid fishes in their current state. Full article

(This article belongs to the Special Issue Evolution and Diversity of Fishes in Deep Time)

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19 pages, 13378 KiB

Open AccessArticle

A New Genus and Species of †Cladocyclidae (Teleostei: †Ichthyodectiformes) from the Lower Cretaceous “Batateira Beds”, Barbalha Formation, Araripe Basin: The First Vertebrate Record in a Still Poorly Explored Fossil Site

by Diogo de Mayrinck, Alexandre Cunha Ribeiro, Mario Luis Assine and André Luis Durante Spigolon

Diversity 2023, 15(3), 413; https://doi.org/10.3390/d15030413 - 11 Mar 2023

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Abstract

The Mesozoic Teleostei †Ichthyodectiformes presents a widespread distribution in marine brackish and freshwater deposits worldwide. The Brazilian fossil record of this group is represented by five nominal genera distributed exclusively in the sedimentary basins of Northeast Brazil (cf. Parnaíba, Sergipe-Alagoas, Recôncavo, Tucano, and [...] Read more.

The Mesozoic Teleostei †Ichthyodectiformes presents a widespread distribution in marine brackish and freshwater deposits worldwide. The Brazilian fossil record of this group is represented by five nominal genera distributed exclusively in the sedimentary basins of Northeast Brazil (cf. Parnaíba, Sergipe-Alagoas, Recôncavo, Tucano, and Araripe). In the Araripe basin, the unique representative of the order is †Cladocyclus gardneri, restricted to the Crato and Romualdo Formations. Recent collecting efforts carried out in the Araripe Basin led to the discovery of two specimens of †Cladocyclidae. Based on the comparison with the known Brazilian taxa, we conclude that this new record represents a new genus and species of this clade. †Cladocynodon araripensis represents the first vertebrate described from the dark shales of the “Batateira Beds” of the Barbalha Formation and differs from the other †Cladocyclidae by the presence of hypertrophied bony fangs at the anterior region of the dentary, with other relatively small true teeth abruptly reduced posteriorly, and by presenting premaxillary and maxillary teeth significantly reduced in size. †Cladocynodon araripensis increases the anatomic diversity and temporal range of †Cladocyclidae in Gondwana. Full article

(This article belongs to the Special Issue Evolution and Diversity of Fishes in Deep Time)

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43 pages, 9735 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Systematics and Phylogenetic Interrelationships of the Enigmatic Late Jurassic Shark Protospinax annectans Woodward, 1918 with Comments on the Shark–Ray Sister Group Relationship

by Patrick L. Jambura, Eduardo Villalobos-Segura, Julia Türtscher, Arnaud Begat, Manuel Andreas Staggl, Sebastian Stumpf, René Kindlimann, Stefanie Klug, Frederic Lacombat, Burkhard Pohl, John G. Maisey, Gavin J. P. Naylor and Jürgen Kriwet

Diversity 2023, 15(3), 311; https://doi.org/10.3390/d15030311 - 21 Feb 2023

Cited by 4 | Viewed by 7036

Abstract

The Late Jurassic elasmobranch Protospinax annectans is often regarded as a key species to our understanding of crown group elasmobranch interrelationships and the evolutionary history of this group. However, since its first description more than 100 years ago, its phylogenetic position within the [...] Read more.

The Late Jurassic elasmobranch Protospinax annectans is often regarded as a key species to our understanding of crown group elasmobranch interrelationships and the evolutionary history of this group. However, since its first description more than 100 years ago, its phylogenetic position within the Elasmobranchii (sharks and rays) has proven controversial, and a closer relationship between Protospinax and each of the posited superorders (Batomorphii, Squalomorphii, and Galeomorphii) has been proposed over the time. Here we revise this controversial taxon based on new holomorphic specimens from the Late Jurassic Konservat-Lagerstätte of the Solnhofen Archipelago in Bavaria (Germany) and review its skeletal morphology, systematics, and phylogenetic interrelationships. A data matrix with 224 morphological characters was compiled and analyzed under a molecular backbone constraint. Our results indicate a close relationship between Protospinax, angel sharks (Squatiniformes), and saw sharks (Pristiophoriformes). However, the revision of our morphological data matrix within a molecular framework highlights the lack of morphological characters defining certain groups, especially sharks of the order Squaliformes, hampering the phylogenetic resolution of Protospinax annectans with certainty. Furthermore, the monophyly of modern sharks retrieved by molecular studies is only weakly supported by morphological data, stressing the need for more characters to align morphological and molecular studies in the future. Full article

(This article belongs to the Special Issue Evolution and Diversity of Fishes in Deep Time)

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24 pages, 2816 KiB

Open AccessEditor’s ChoiceArticle

Lungfish and the Long Defeat

by Anne Kemp

Diversity 2023, 15(1), 63; https://doi.org/10.3390/d15010063 - 04 Jan 2023

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Abstract

Australia has an excellent fossil record of lungfish that begins in the Devonian and includes many species in Tertiary and Quaternary deposits. The extant Australian lungfish, Neoceratodus forsteri, occurs in Pliocene deposits, but is now restricted to a handful of coastal rivers [...] Read more.

Australia has an excellent fossil record of lungfish that begins in the Devonian and includes many species in Tertiary and Quaternary deposits. The extant Australian lungfish, Neoceratodus forsteri, occurs in Pliocene deposits, but is now restricted to a handful of coastal rivers in Queensland. Some of the fossil taxa, belonging to species related to N. forsteri, are represented by only a few specimens, but others include large numbers of tooth plates. The existence of these taxa, even if they are represented by only a few specimens, indicates that lungfish were present in lakes and rivers in central and northern Australia in the past, and that the potential habitats for these fish were more extensive then than they are now. Many of the fossil populations died out because Australia became more arid, and the remaining species became isolated in large river systems in the north and east of the continent. However, the cause of extinction of some fossil populations was not always related to increasing aridity. Several fossil populations were apparently living in poor conditions. They stopped spawning and adding new members to the population. The remaining individuals showed advanced age and many diseases before the population disappeared. This can be observed in the present day, and one population in an isolated reservoir is already extinct. Full article

(This article belongs to the Special Issue Evolution and Diversity of Fishes in Deep Time)

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42 pages, 10504 KiB

Open AccessEditor’s ChoiceArticle

A New Large †Pachycormiform (Teleosteomorpha: †Pachycormiformes) from the Lower Jurassic of Germany, with Affinities to the Suspension-Feeding Clade, and Comments on the Gastrointestinal Anatomy of Pachycormid Fishes

by Samuel L. A. Cooper, Sam Giles, Holly Young and Erin E. Maxwell

Diversity 2022, 14(12), 1026; https://doi.org/10.3390/d14121026 - 24 Nov 2022

Cited by 5 | Viewed by 3149

Abstract

Pachycormiformes is a diverse clade of stem-teleost actinopterygian fishes with a stratigraphic range from the Lower Jurassic (Toarcian) to Upper Cretaceous (Maastrichtian). The Toarcian Posidonienschiefer Formation in SW Germany records the earliest occurrence of †Pachycormiformes in the fossil record, offering unique and crucial [...] Read more.

Pachycormiformes is a diverse clade of stem-teleost actinopterygian fishes with a stratigraphic range from the Lower Jurassic (Toarcian) to Upper Cretaceous (Maastrichtian). The Toarcian Posidonienschiefer Formation in SW Germany records the earliest occurrence of †Pachycormiformes in the fossil record, offering unique and crucial insight into the clade’s origins and early adaptive radiation in the Early Jurassic. However, Early Jurassic taxa remain poorly studied with the taxonomic diversity and stratigraphic/geographic distributions insufficiently defined, thus masking the early part of this evolutionary radiation. Here, we report a new genus and species of pachycormid fish from the Posidonienschiefer Formation identified by phylogenetic analysis as falling in an intermediate position between Saurostomus and Ohmdenia at the base of the suspension-feeding clade. The new taxon shows a unique suite of cranial and postcranial characters. Several synapomorphies of the suspension-feeding clade, notably, the morphology of the hyomandibula, elongation of the skull, and reduced squamation are shared with the new taxon. The intestinal tract is exceptionally preserved, providing one of the most complete examples of pachycormid gastric anatomy. A comparison of the gastrointestinal anatomy of the new genus with other pachycormiforms indicates extensive taxonomic variation within the clade, in the configuration of both the midgut and spiral valve, potentially related to trophic divergence. The results highlight an underestimated high diversity and the rapid acquisition of trophic specializations in Pachycormiformes much earlier in the clade’s evolution than previously considered. Full article

(This article belongs to the Special Issue Evolution and Diversity of Fishes in Deep Time)

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20 pages, 4754 KiB

Open AccessEditor’s ChoiceArticle

Osteichthyan Fishes from the uppermost Norian (Triassic) of the Fuchsberg near Seinstedt, Lower Saxony (Germany)

by Hans-Peter Schultze, Gloria Arratia, Norbert Hauschke and Volker Wilde

Diversity 2022, 14(11), 901; https://doi.org/10.3390/d14110901 - 25 Oct 2022

Cited by 1 | Viewed by 2262

Abstract

Fishes from the uppermost Norian Fuchsberg Quarry near Seinstedt are represented by two taxa that we interpret as a teleosteomorph (complete specimens) and actinistian (scales). Seinstedtia parva gen. et sp. nov. is described; although it was proposed as a possible semionotiform, this study [...] Read more.

Fishes from the uppermost Norian Fuchsberg Quarry near Seinstedt are represented by two taxa that we interpret as a teleosteomorph (complete specimens) and actinistian (scales). Seinstedtia parva gen. et sp. nov. is described; although it was proposed as a possible semionotiform, this study reveals that Seinstedtia possesses a combination of teleosteomorph features, for instance: characteristic pholidophoriform-shaped cranial roof; fusion of skull roof bones; three dorso-posterior infraorbitals, including an enlarged infraorbital 3; one suborbital bone; movable premaxilla; and characteristic-shaped preopercle. In parallel, Seinstedtia possesses a head gently curved anteriorly, with lower jaw protruding slightly in front of upper jaw; supraorbital 1 forming most of antero-dorsal margin of circumorbital ring; one supramaxilla; three extrascapulae; cleithrum with short and broad lower arm; and enlarged clavicle. This character combination places Seinstedtia as a teleosteomorph, family incertae sedis. This fish (total length ca. 50 mm) and some pholidophorids (ca. 70 mm or less; Parapholidophorus nybelini and Pholidoctenus serianus) represent the known smallest teleosteomorphs that inhabited Europe during the Norian. The isolated scales are elasmoid of amioid type ornamented with the elongated ridges of actinistians. This diversity of teleosteomorphs and actinistians in Fuchsberg Quarry during the Triassic indicates a connection to a marine environment. Full article

(This article belongs to the Special Issue Evolution and Diversity of Fishes in Deep Time)

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61 pages, 45929 KiB

Open AccessArticle

The Phylogeny of Rays and Skates (Chondrichthyes: Elasmobranchii) Based on Morphological Characters Revisited

by Eduardo Villalobos-Segura, Giuseppe Marramà, Giorgio Carnevale, Kerin M. Claeson, Charlie J. Underwood, Gavin J. P. Naylor and Jürgen Kriwet

Diversity 2022, 14(6), 456; https://doi.org/10.3390/d14060456 - 06 Jun 2022

Cited by 10 | Viewed by 5642

Abstract

Elasmobranchii are relatively well-studied. However, numerous phylogenetic uncertainties about their relationships remain. Here, we revisit the phylogenetic evidence based on a detailed morphological re-evaluation of all the major extant batomorph clades (skates and rays), including several holomorphic fossil taxa from the Palaeozoic, Mesozoic [...] Read more.

Elasmobranchii are relatively well-studied. However, numerous phylogenetic uncertainties about their relationships remain. Here, we revisit the phylogenetic evidence based on a detailed morphological re-evaluation of all the major extant batomorph clades (skates and rays), including several holomorphic fossil taxa from the Palaeozoic, Mesozoic and Cenozoic, and an extensive outgroup sampling, which includes sharks, chimaeras and several other fossil chondrichthyans. The parsimony and maximum-likelihood analyses found more resolved but contrasting topologies, with the Bayesian inference tree neither supporting nor disfavouring any of them. Overall, the analyses result in similar clade compositions and topologies, with the Jurassic batomorphs forming the sister clade to all the other batomorphs, whilst all the Cretaceous batomorphs are nested within the remaining main clades. The disparate arrangements recovered under the different criteria suggest that a detailed study of Jurassic taxa is of utmost importance to present a more consistent topology in the deeper nodes, as issues continue to be present when analysing those clades previously recognized only by molecular analyses (e.g., Rhinopristiformes and Torpediniformes). The consistent placement of fossil taxa within specific groups by the different phylogenetic criteria is promising and indicates that the inclusion of more fossil taxa in the present matrix will likely not cause loss of resolution, therefore suggesting that a strong phylogenetic signal can be recovered from fossil taxa. Full article

(This article belongs to the Special Issue Evolution and Diversity of Fishes in Deep Time)

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9 pages, 1432 KiB

Open AccessBrief Report

The First Fossil Coelacanth from Thailand

by Lionel Cavin, Haiyan Tong, Eric Buffetaut, Kamonlak Wongko, Varavudh Suteethorn and Uthumporn Deesri

Diversity 2023, 15(2), 286; https://doi.org/10.3390/d15020286 - 16 Feb 2023

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Abstract

Mawsoniidae is a family of coelacanths restricted to the Mesozoic. During the Cretaceous, mawsoniids were mainly represented by the Mawsonia/Axelrodichthy complex, long known to be from western Gondwana only (South America and Africa). This apparent biogeographical distribution then faded following the [...] Read more.

Mawsoniidae is a family of coelacanths restricted to the Mesozoic. During the Cretaceous, mawsoniids were mainly represented by the Mawsonia/Axelrodichthy complex, long known to be from western Gondwana only (South America and Africa). This apparent biogeographical distribution then faded following the discovery of representatives in the Late Cretaceous of Laurasia (Europe and North America). We report here the presence, in the Lower Cretaceous site of Kham Phok, NE Thailand, of an angular bone referred to the Mawsonia/Axelrodichthys complex. A comparison with angulars referring to both genera found in various regions of the world between the Late Jurassic and the Late Cretaceous indicated that the distinctions between these genera, and even more so between their constituent species, are unclear. This discovery is further confirmation of the very slow morphological evolution within this lineage, which may explain why their evolutionary history appears to be disconnected, at least in part, from their geographical distribution over time. Full article

(This article belongs to the Special Issue Evolution and Diversity of Fishes in Deep Time)

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