[PaleoMammalogy • 2026] Archaeomeles neglecta • A New Genus of Badger from Pikermi (Greece) and A Review of the Systematics and Evolution of Miocene Melinae (Carnivora: Mustelidae)

Archaeomeles neglecta 

Kargopoulos, Valenciano, Jiangzuo, Liakopoulou, Gerakakis, Kampouridis, Paparizos, Svorligkou, Filis, Sklavounou & Roussiakis, 2026

  DOI: doi.org/10.1080/14772019.2026.2647483  

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Abstract

The evolution of Mustelidae has been a topic of debate, obscured by a complex system of convergences between phylogenetically distant groups. In this work, we present a new genus and species of mustelid, Archaeomeles neglecta gen. et sp. nov., from the classical Turolian locality of Pikermi (Greece, Late Miocene, MN12). The material consists of a skull with the associated mandible and shows distinct features that clearly differentiate it from all other known mustelid genera. These characteristics include a long and narrow rostrum, the absence of developed sagittal and supraorbital crest, relatively slender mandibular corpus, enamel folds on the lower canines, the wide P3 and p4, and the moderately enlarged M1 talon and m1 talonid. Morphometrical comparisons and phylogenetic analysis suggest that Archaeomeles is a stem member of the Melinae along with the other Turolian mustelids Promeles, Polgardia and Melodon from Eurasia. Ecomorphological comparisons indicate intermediate dietary habits between the plesiomorphic gulonines and the derived extant badgers, suggesting a diet that is based on small vertebrates and invertebrates as well as plant material. 

Keywords: Carnivora, Ecomorphology, Mustelidae, Phylogeny, Turolian

Systematic palaeontology

Order Carnivora Bowdich, 1821

Suborder Caniformia Kretzoi, 1943

Family Mustelidae Batsch, 1788

Subfamily Melinae Bonaparte, 1838

Genus Archaeomeles gen. nov.

Type and only species. Archaeomeles neglecta sp. nov.

Diagnosis: Mustelid of the size of the extant European otter (Lutra lutra); rostrum long and slender; P1/p1 present; P2/p2 two-rooted; P3 significantly wide; P4 moderately shortened; P4 with hypocone region moderately developed; M1 moderately expanded distolingually, with metaconule and a high protocone; mandibular corpus slender; lower canine with enamel folds; p4 slender without marked accessory cuspids, m1 with low trigonid cuspids, talonid moderately enlarged and basin-like, without entoconid and entoconulid, but with distinct hypoconid and a minute, buccally situated hypoconulid.

Derivation of name: Archaeo-, from the Greek word Ἀρχαῖος meaning ancient, and -meles meaning badger. The name Archaeomeles, ‘ancient badger’, is chosen to highlight its key position in the radiation of the Melinae in the Turolian.

Archaeomeles neglecta sp. nov.

Holotype. AMPG-P.A. 4879/91 – skull with an associated mandible.

 

Derivation of name. The specific name neglecta comes from the feminine of the Latin word neglectus meaning neglected. It refers to the holotype being overlooked in the collections of AMPG for over a century.

Type Locality. Pikermi (classical layers), Attica, Greece.

Age. 7.33–7.29Ma, Turolian, Late Miocene (MN 12).

 

Nikolaos Kargopoulos, Alberto Valenciano, Qigao Jiangzuo, Dionysia Liakopoulou, Nikolaos Gerakakis, Panagiotis Kampouridis, Nikolaos Paparizos, Georgia Svorligkou, Panagiotis Filis, Stamatina Sklavounou and Socrates Roussiakis. 2026. A New Genus of Badger from Pikermi (Greece) and A Review of the Systematics and Evolution of Miocene Melinae (Mammalia, Carnivora, Mustelidae). Journal of Systematic Palaeontology. 24(1); 2647483.  DOI: doi.org/10.1080/14772019.2026.2647483 [24 Apr 2026]

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[Paleontology • 2026] Labyrinth Morphology of Eunotosaurus africanus in the Context of Semicircular Canal Shape Variation across Amniotes

 Eunotosaurus africanus with in-set labyrinth

in Evers, Panigot, Petermann, Rubidge, Bever et Lyson, 2026.

DOI: doi.org/10.1080/14772019.2026.2634330  

Life reconstruction by Andrey Atuchin.

Abstract

The Middle Permian reptile Eunotosaurus africanus is a key taxon for understanding reptile evolution because it has been proposed to be one of the earliest stem turtles, but it could alternatively represent an early sauropsid. Alternative evolutionary interpretations are based on morphological character observations, and comparative anatomy of previously undocumented body parts may yield novel character evidence. Based on a previously unreported specimen of Eunotosaurus africanus, we provide descriptions of its inner ear anatomy, which we compare to a diversity of amniotes including turtles, millerettids and novel segmentations of Youngina capensis and Champsosaurus lindoei. The inner ear of Eunotosaurus africanus has plesiomorphic neodiapsid inner ear features that contrast with turtle ear morphology, including a radius of curvature of the anterior semicircular canal (ASC) that is larger than that of the posterior semicircular canal (PSC), narrow intercanal angles, slender vertical semicircular canals, and a bend in the central section of the PSC. Eunotosaurus africanus shares with turtles a large common crus cross-section and a thickened lateral semicircular canal. We provide a landmark-based comparison of amniote labyrinth shapes, which shows principal differences in the semicircular canals of birds, mammals and turtles as end members of a gradient of semicircular canal geometries. Other extant amniote groups (crocodiles, lepidosaurs), fossil lineages (e.g. sauropterygians, captorhinids, millerettids, younginiforms, varanopids, Eunotosaurus africanus) and stem lineages of extant groups (e.g. pterosaurs, non-avian dinosaurs, phytosaurs, other extinct pseudosuchians, mosasaurs, ‘pelycosaurs’, dicynodonts) show semicircular canal geometries that are generally intermediate between extreme shapes of birds, mammals and turtles, so that the entire morphospace shows gradational morphologies. The observed variation provides evidence of convergent evolution of labyrinth features, but also suggests phylogenetic signal is widespread in labyrinth morphology and that bird, mammal, and turtle labyrinth shapes may have evolved from a plesiomorphic shape that was retained in many reptilian stem lineages.

Keywords: neuroanatomy, inner ears, emicircular canal geometry, amniote phylogeny, turtle origins

Photographs of Eunotosaurus africanus (BP/1/7852). A, dorsal view. B, ventral view. Arabic numerals indicate position of vertebra or rib. Note that the spacing between pre- and postzygapophyses of dorsal vertebra seven in A demonstrates the elongate vertebral centra.

Abbreviations: cor, coracoid; cra, cranium; cvs, cervical vertebral series; d, dorsal vertebra; hu, humerus; icl, interclavicle; man, mandible; poz, postzygapophysis; prz, prezygapophysis; sc, scapula; tr, thoracic rib.

  Life reconstruction of Eunotosaurus africanus with in-set labyrinth

reconstruction by Andrey Atuchin.

 

Serjoscha W. Evers, Eldon Panigot, Holger Petermann, Bruce S. Rubidge, Gabriel S. Bever and Tyler R. Lyson. 2026. Labyrinth Morphology of Eunotosaurus africanus in the Context of Semicircular Canal Shape Variation across Amniotes. Journal of Systematic Palaeontology. 24(1); 2634330. DOI: doi.org/10.1080/14772019.2026.2634330   [30 Mar 2026]

[Paleontology • 2026] Crocodylus lucivenator • Lucy’s peril: A Pliocene crocodile from the Hadar Formation, north-eastern Ethiopia

  

Crocodylus lucivenator

 Brochu, Drumheller, Campisano, Tekle, Getachew, Head, Platt & Leaphart, 2026

 

DOI: doi.org/10.1080/14772019.2026.2614954 

Artwork by Tyler Stone

Abstract

We herein describe a new crocodile, Crocodylus lucivenator sp. nov., from palaeoanthropological sites in the Pliocene Hadar Formation in north-eastern Ethiopia. It shares derived features and plesiomorphic states with two Pleistocene species of Crocodylus from East Africa. Conversely, C. lucivenator bears a midline boss on the dorsal surface of the rostrum similar to those of modern Neotropical crocodiles and late Miocene crocodiles from Libya and Kenya. A boss is also present on Pliocene specimens from Kanapoi in Kenya previously referred to C. thorbjarnarsoni. Some C. lucivenator also have a more substantial prenarial rostrum than other Palaeoafrican Crocodylus, though not to the same extent as in extant Crocodylus, and its expression is variable. Phylogenetic analysis supports a close relationship between C. lucivenator, Kanapoi Crocodylus, C. anthropophagus, C. thorbjarnarsoni, and fossils from the Turkana Basin previously misreferred to C. checchiai. A close relationship with Neoafrican Crocodylus is rejected, reinforcing a comparatively recent arrival for Neoafrican Crocodylus in East Africa. Crocodylus lucivenator and the Kanapoi form are very similar, but an exclusive relationship is not unambiguously supported in our analysis. The phylogenetic placement of the Palaeoafrican clade depends on how one regards the prenarial rostrum, and positions outside crown Crocodylus or close to the Neotropical clade can be equally optimal. One mandible preserves pathological structures consistent with injuries sustained during intraspecific combat. Crocodylus lucivenator appears to have been the only crocodylian in the Hadar Formation, while coeval deposits in the Turkana Basin preserve as many as four species. The reason for this disparity is unclear.

 

Keywords: Crocodylus lucivenator, Hadar Formation, Pliocene, prenarial rostrum, cladistic assessment, Turkana Basin

Crocodylus lucivenator sp. nov.

Etymology. luci-, Latin for light, but here used with reference to A.L. 288-1 (Lucy), the iconic Australopithecus afarensis skeleton from Hadar; -venator, Latin, hunter. There is no evidence A.L. 288-1 was ever attacked by a crocodile, but her species (and most likely Lucy herself) would doubtless have been pursued as prey by this species.

Christopher A. Brochu, Stephanie K. Drumheller, Christopher Campisano, Getahun Tekle, Tomas Getachew, Jason J. Head, Nathan C. Platt & Daniel Leaphart. 2026. Lucy’s peril: A Pliocene crocodile from the Hadar Formation, north-eastern Ethiopia. Journal of Systematic Palaeontology. 24(1); 2614954. DOI: doi.org/10.1080/14772019.2026.2614954 [11 Mar 2026]

[Paleontology • 2026] Nabia civiscientrix • New albanerpetontid Species (Lissamphibia) from the Late Jurassic of Portugal

 

Nabia civiscientrix 

Guillaume, Evans, Jones, Puértolas-Pascual & Moreno-Azanza, 2026

DOI: doi.org/10.1080/14772019.2025.2580623

Illustration by Eva Carret

Abstract

The Albanerpetontidae are a group of small extinct lissamphibians ranging from the Bathonian to the early Pleistocene. The Upper Jurassic of Portugal is known to yield a large collection of albanerpetontid remains, ascribed to the genus Celtedens. However, recent studies have shown that the frontal bones used for species diagnosis display important intraspecific variation. Here, we describe 468 bones from the Kimmeridgian-Tithonian Lourinhã Formation, together with thousands of remains from the Guimarota beds of the Kimmeridgian Alcobaça Formation. They support the erection of a new genus and species, Nabia civiscientrix gen. et sp. nov., characterized by a unique combination of five synapomorphies: a bulbous/flabellate outline of the internasal process of the frontal in dorsal or ventral view; no sculpture on the postorbital wing of the parietals; the dorsal condyle of the axis with a recurved edge; the long axis of the iliac shaft strongly tilted posteriorly; and a limited pubic/ischial articulation flaring. This material represents the oldest albanerpetontid species from the Iberian Peninsula and potentially the third described from the Jurassic, during which time it played a major palaeobiogeographical role in relation to Europe, north-western Africa and North America. Our results further confirm the need to revise Celtedens. The material from the Lourinhã Formation suggests that other multi-specific microfossil vertebrate bonebeds should contain a greater variety of elements than is reported. We stress the need to review unpicked and unidentified material to look for postcranial bones rather than focusing only on cranial elements, as in combination they aid a better characterisation of this group.

 

Keywords: Albanerpetontidae, Kimmeridgian–Tithonian, Lourinhã Formation, Guimarota, systematics

Nabia civiscientrix gen. et sp. nov.

Alexandre R. D. Guillaume, Susan E. Evans, Marc E. H. Jones, Eduardo Puértolas-Pascual and Miguel Moreno-Azanza. 2026. New albanerpetontid Species (Lissamphibia) from the Late Jurassic of Portugal. Journal of Systematic Palaeontology. 24(1); 2580623. DOI: doi.org/10.1080/14772019.2025.2580623 [23 Jan 2026]

  

[Paleontology • 2025] Tainrakuasuchus bellator • Osteology, Taxonomy and Phylogenetic Affinities of A New pseudosuchian Archosaur from the Middle Triassic of southern Brazil

  

Tainrakuasuchus bellator 

 Müller, Garcia, Damke, Prestes de Bem, Fonseca, Doering, Schiefelbein & Laste, 2025

DOI: doi.org/10.1080/14772019.2025.2573750

Artwork by Caio Fantini. 

 

Abstract

Following the end-Permian mass extinction, archosaurs underwent rapid taxonomic and morphological diversification. While the avian lineage expanded into a broader range of ecological niches during the Late Triassic, the crocodilian lineage dominated ecosystems as early as the Middle Triassic, achieving an impressive range of morphological variation. Among the several pseudosuchian radiations that characterized the Middle Triassic, Poposauroidea stands out as one of the most enigmatic groups. From the Early to the Late Triassic, poposauroids evolved diverse body plans: some species developed dorsal ‘sails’, others became entirely edentulous, some adopted bipedal postures, and others occupied apex predator roles. In South America, the fossil record of Poposauroidea during the Middle Triassic is relatively scarce, being limited to Schultzsuchus loricatus, a relatively large-bodied predator known from fragmentary remains collected at a site within the Pinheiros–Chiniquá Sequence. In the present study, we describe Tainrakuasuchus bellator gen. et sp. nov., a new poposauroid from Brazil. The holotype was discovered at a locality known as the Posto Site, in the municipality of Dona Francisca (Pinheiros–Chiniquá Sequence; Middle Triassic). The specimen preserves a partial lower jaw, cervical and dorsal vertebrae, and an ilium. Tainrakuasuchus bellator gen. et sp. nov. is characterized by a slender mandible, ziphodont dentition and relatively elongated cervical vertebrae, representing a new medium-sized predatory archosaur. Phylogenetic analyses suggest affinities with Mandasuchus tanyauchen, a putative poposauroid from the Tanzanian Manda beds. The close relationship between these taxa, along with the strong faunal similarities between the respective geological units, reinforces the correlation between units and supports a Ladinian age. Finally, the discovery of Tainrakuasuchus bellator gen. et sp. nov. expands the known taxonomic diversity of the Dinodontosaurus Assemblage Zone and provides new insights into the key role played by pseudosuchians in the complex ecosystems of the Middle Triassic of south-western Gondwana.

 

Keywords: cladistics, Gondwana, Ladinian, Paracrocodilomorpha, Poposauroidea

Systematic palaeontology

Archosauria Cope, Citation1869

Pseudosuchia Zittel, Citation1887–1890

Paracrocodylomorpha Parrish, Citation1993

Tainrakuasuchus bellator gen. et sp. nov.

Etymology. The combination of Guarani tain, tooth, and rakua, pointed, with Greek suchus, crocodile; referring to the pointed teeth of the lower jaw. The specific epithet bellator is derived from Latin, meaning ‘warrior’ or ‘fighter’. It serves as a tribute to the people of Rio Grande do Sul, honouring their historical resilience and enduring spirit, particularly in light of the recent severe flooding that has impacted the state.

 Artistic representation of a Middle Triassic landscape of southern Brazil depicting Tainrakuasuchus bellator gen. et sp. nov.

Artwork by Caio Fantini.

 

Rodrigo Temp Müller, Mauricio Silva Garcia, Lísie Vitória Soares Damke, Fabiula Prestes de Bem, André de Oliveira Fonseca, Mariana Doering, Jeung Hee Schiefelbein and Vitória Zanchett Dalle Laste. 2025. Osteology, Taxonomy and Phylogenetic Affinities of A New pseudosuchian Archosaur from the Middle Triassic of southern Brazil. Journal of Systematic Palaeontology. 23(1); 2573750. DOI: doi.org/10.1080/14772019.2025.2573750 [12 Nov 2025]

[Paleontology • 2025] Latonia dimenticata • Why extant, Why not Extinct? A New extinct Latonia Species (Anura: Discoglossidae) from the Early Pleistocene of the Apennine Peninsula provides clues on the survival of the genus in Eurasia

 

 Latonia dimenticata 

 Sorbelli, Azzarà, Cherin, Delfino, Roček & Villa, 2025

 

DOI: doi.org/10.1080/14772019.2025.2554727 

artwork: Leonardo Sorbelli

 

Abstract

Pietrafitta is one of the richest Early Pleistocene localities in the Italian Peninsula and it hosts one of the latest occurrences of the discoglossid frog Latonia in Europe. This occurrence is here described as a new species of Latonia, a large-bodied frog, potentially feeding on hard invertebrates in the Pietrafitta palaeoswamp. Our first attempt at the phylogenetic reconstruction of Latonia, based on a matrix consisting of 20 taxa and 39 characters, placed the new Italian species within a poorly understood clade that also includes Latonia caucasica from the Late Miocene of northern Caucasus. Almost all other extinct Latonia species make up a second clade, represented in the fossil record from the Oligocene and including the youngest occurrence of the genus in Europe, from the Middle Pleistocene of Hungary. The only extant species, Latonia nigriventer, was the earliest branching taxon in our topology, which could be due to its unique unsculptured morphology, a trait that may represent a secondary loss during the Quaternary. The exostosis on cranial bones, which is considered a diagnostic feature of the genus, might have developed in the earliest Latonia in response to pronounced warming and drought. Later, starting after the Middle Miocene, this exostosis underwent a reduction process, possibly triggered by cooling, that led to Plio–Pleistocene forms sharing a narrower frontoparietal with a less pustular sculpturing. Latonia dimenticata is a clear example of this frontoparietal morphology. Latonia nigriventer may have further evolved a completely unsculptured morphology to face rapid environmental changes in the last Quaternary glacial phases and ultimately facilitating its survival into the present day.  

Keywords: Quaternary, Italian Peninsula, Europe, Middle East, Latonia nigriventer, exostosis

Latonia dimenticata sp. nov. 

Leonardo Sorbelli, Beatrice Azzarà, Marco Cherin, Massimo Delfino, Zbyněk Roček and Andrea Villa. 2025. Why extant, Why not Extinct? A New extinct Latonia Species (Anura: Discoglossidae) from the Early Pleistocene of the Apennine Peninsula provides clues on the survival of the genus in Eurasia. Journal of Systematic Palaeontology. 23(1); 2554727. DOI: doi.org/10.1080/14772019.2025.2554727 [10 Oct 2025]

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[Paleontology • 2025] Cariocecus bocagei • A New basal hadrosauroid from the Lower Cretaceous of Portugal

 Cariocecus bocagei

Bertozzo, Camilo, Araújo, Manucci, Kullberg & Cerio, 2025

 

 DOI: doi.org/10.1080/14772019.2025.2536347  

  facebook.com: Bruno Camilo Silva   

Artwork by Victor F. Carvalho  

Abstract

In Portugal, iguanodontian dinosaurs are mostly known from the Late Jurassic of the Lourinhã Formation and are represented by dryosaurids and basal styracosternans. The Early Cretaceous record of iguanodontians in Portugal is scarce in comparison, with scattered and uninformative remains referred to Styracosterna indet. Here, we describe SHN.832, the first iguanodontian skull from Portugal, named Cariocecus bocagei gen. nov. sp. nov. The specimen was found in Praia do Areia do Mastro (Cabo Espichel, Sesimbra) in the Papo Seco Formation (lower Barremian), and comprises the right side of the skull, part of the skull vault and a nearly complete basicranium. Cariocecus bocagei is diagnosed based on autapomorphies such as the co-ossified maxillo-jugal complex and the trilobated shape of the supraoccipital. The phylogenetic analysis retrieves C. bocagei as a basal hadrosauroid in a clade with Comptonatus chasei and Brighstoneus simmondsi. Our biogeographical analysis emphasizes the effects of insular endemism during the Hauterivian–Aptian range in the European regions. We show that Iguanodontia originated in South America, and through a dispersal event towards North America during the Upper Jurassic, expanded their latitudinal range. Cariocecus and other early-diverging iguanodontians emerged during an eastward dispersal event in the Lower Cretaceous. We reconstructed the endocast, cranial nerves and inner ear of Cariocecus via segmentation of micro-computed tomography scanning, showing similarities with other Hadrosauriformes such as Iguanodon and Proa. We propose the most detailed inner ear soft-tissue reconstruction for a dinosaur so far, including the macula and sub-branches of the vestibulocochlear nerve, supported by the extant phylogenetic bracket. Based on the unossified suture of the cranial elements, we hypothesize that SHN.832 had not yet reached full skeletal maturity, and our restoration suggests a total skull length of about 45 cm. The supraorbital membrane was reconstructed based on the well-preserved supraorbital bone and comparison with modern taxa. 

Keywords: Ornithopoda, Barremian, Papo Seco Formation, supraorbital, biogeography

 

Cariocecus bocagei gen. nov. sp. nov. 

  

 

Filippo Bertozzo, Bruno Camilo, Ricardo Araújo, Fabio Manucci, José Carlos Kullberg, Donald G. Cerio. 2025. Cariocecus bocagei, A New basal hadrosauroid from the Lower Cretaceous of Portugal. Journal of Systematic Palaeontology. 23(1); 2536347. DOI: doi.org/10.1080/14772019.2025.2536347 [15 Sep 2025] 

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[Paleontology • 2025] Traskasaura sandrae • A Name for the Provincial Fossil of British Columbia: A Strange New elasmosaur Taxon from the Santonian of Vancouver Island

 

Traskasaura sandrae

O’Keefe, Smith, Clark, Otero, Perella & Trask, 2025

DOI: doi.org/10.1080/14772019.2025.2489938 

Abstract

The first elasmosaurid skeleton from the Haslam Formation (Upper Santonian) of the Nanaimo Group (Late Cretaceous) on Vancouver Island was first described in 2002, and has recently been declared the Provincial Fossil of British Columbia. Since then, additional fossils have been recovered: an isolated right humerus and a well-preserved, osteologically immature skeleton comprising thorax, girdles and limbs. The Haslam material can now support further taxonomic assessment, and we erect the species Traskasaura sandrae based on it. Traskasaura possesses a strange mosaic of features. The mandible is plesiomorphic as seen in Libonectes: relatively narrow with large teeth and a broad symphysis. The skull therefore lacks any of the radical oral cavity adaptations seen in basal aristonectines. The neck of the Haslam animal is also plesiomorphic, with at least 36 preserved cervical vertebrae having vertebral length indices (VLIs) over 100 (the total number of cervicals is not known). The centra lack the anteroposterior compression and midline longitudinal constriction characteristic of derived aristonectines, yet the cervical ribs trend forward – a condition known only in derived aristonectines and Vegasaurus. The autapomorphic coracoid of Traskasaura differs greatly from any known elasmosaurid; the cardiform recess is reduced and posteriorly located, with some similarities to that of Aristonectes quiriquinensis. The humerus is autapomorphic, possessing a relatively straight shaft, pronounced ventral camber and an articular facet on the leading edge that makes a 90° angle with the radial facet. Taken together, these features document a new genus, with a plesiomorphic axial skeleton, but with several convergent appendicular adaptations with derived aristonectines. A revised phylogenetic analysis of Elasmosauridae recovered the new taxon in a basal position. Therefore, the postcranial adaptations shared with derived aristonectines appear to be convergent.

Keywords: elasmosaur, Haslam Formation, plesiosaur, Santonian

Sauropterygia Owen, Citation1860

Order Plesiosauria de Blainville, Citation1835

Family Elasmosauridae Cope, Citation1869

Traskasaura sandrae gen. et sp. nov.

Etymology: The genus is named in honour of Michael and Heather Trask, who discovered the holotype specimen along the banks of the Puntledge river in 1988, and the Greek word saûros, lizard; the Latin conjugation is feminine. The species name sandrae honours Sandra Lee O’Keefe (née Markey), Pacific Northwest native and, like Elizabeth Nicholls, a valiant warrior in the fight against breast cancer. In loving memory.

F. Robin O’Keefe, Elliott Armour Smith, Robert O. Clark, Rodrigo A. Otero, Anna Perella and Patrick Trask. 2025. A Name for the Provincial Fossil of British Columbia: A Strange New elasmosaur Taxon from the Santonian of Vancouver Island. Journal of Systematic Palaeontology. 23(1); 2489938. DOI: doi.org/10.1080/14772019.2025.2489938 [22 May 2025] 

[PaleoIchthyology • 2023] Iridopristis parrisi • An earliest Paleocene squirrelfish (Beryciformes: Holocentroidea) and its bearing on the timescale of holocentroid evolution

Iridopristis parrisi

Andrews, Schein & Friedman, 2023

DOI: doi.org/10.1080/14772019.2023.2168571 

 x.com/kryptophanaron

Abstract

The record of articulated marine fish fossils during the latest Cretaceous and earliest Cenozoic is sparse. The oldest-known definitive squirrelfishes and soldierfishes, like the first examples of many extant reef-dwelling clades, are known from early Eocene deposits of Europe. Here, we describe a new genus and species of holocentroid (Teleostei: Beryciformes: Holocentroidea) based on material from three individuals from early Paleocene (Danian) deposits of New Jersey, USA using micro-computed tomography. The specimens comprise a three-dimensionally preserved skull and partial postcranium, plus two isolated neurocrania. The new taxon, †Iridopristis parrisi, possesses a unique combination of characters, including a heterosulcoid otolith morphology and an edentulous premaxillary tooth-gap, while lacking a newly proposed character for the remainder of Cenozoic holocentroids: a lamina on the lateral surface of the anguloarticular, anterior to the jaw joint. Bayesian phylogenetic analysis of morphological, stratigraphical and molecular data under the fossilized birth-death process finds that the new taxon branches from the holocentrid stem, where it is joined by two of the three squirrelfish genera from the early Eocene (Ypresian) of Bolca, Italy. We estimate a Danian divergence between Myripristinae and Holocentrinae, the two reciprocally monophyletic subfamilies of Holocentridae. Our analysis suggests that several holocentroid lineages crossed the Cretaceous–Palaeogene boundary.

 

Keywords: Acanthomorpha, Cretaceous–Palaeogene boundary, squirrelfishes, computed tomography, Bayesian phylogenetics, parsimony

Skull and abdomen of †Iridopristis parrisi in left lateral view.
Holotype (NJSM GP12145), Hornerstown Formation, early Paleocene (Danian), New Jersey, USA.
A, specimen photograph and B, rendered µCT model.

Skeletal regions highlighted as follows: neurocranium (pink), suspensorium (purple), circumorbitals (coral), jaws (light blue), opercles (light orange), ventral hyoid (light green), gill skeleton (dark green), pectoral girdle (yellow), abdominal scales (dark orange), vertebral column (red). Arrow indicates anatomical anterior. Scale bar represents 5 cm.

 Squamation of †Iridopristis parrisi. Holotype (NJSM GP12145), Hornerstown Formation, early Paleocene (Danian), New Jersey, USA.
Photographs of the A, cheek and B, abdominal squamation. Arrows indicate anatomical anterior. Scale bars represent 1 cm.

Infraclass Teleostei Müller, 1845

Subsection Acanthomorphata Rosen, 1973

Order Beryciformes Regan, 1911 sensu Dornburg & Near, 2021

Superfamily Holocentroidea Richardson, 1846 sensu Gayet, 1980b

Genus † Iridopristis gen. nov.

† Iridopristis parrisi sp. nov.

Diagnosis: Holocentroid with the unique combination of the following characters: orbital branch of the supraorbital sensory canal with a separate opening from the main channel of the canal; large supraoccipital crest which is triangular in lateral aspect and borders the foramen magnum; parasphenoid with ventrolateral wings; lack of a berycimorph foramen in the anterior ceratohyal; deeply notched ventral surface of the anterior ceratohyal to accommodate branchiostegals; elongate postmaxillary process of the premaxilla; maxillary shaft approximately cylindrical in cross-section and elongate; presence of an alveolar platform expanded outwardly at the symphyseal area of the dentary; distinct edentulous concavity along the mesial margin of the premaxilla; unornamented triangular facet present on the posterolateral surface of the maxilla; edentulous ectopterygoid; head of quadrate posterior to orbital margin; an unexpanded otic bulla; an otolith morphology more similar to that found in holocentrine squirrelfishes (heterosulcoid) than the specialized phenotype of myripristine soldierfishes; lack of a dorsally projecting lamina directly anterior to the anguloarticular-quadrate joint on the lateral surface of the anguloarticular; eleven abdominal centra; cycloid scales with spinoid posterior edge.

Derivation of name: 

The prefix of the generic name (Irido-) from the Greek genitive declension of iridis, meaning ‘rainbow’, and serving as the etymological root for the element iridium. This refers dually to the mosaic nature of characters present in the specimen, and for its occurrence close to the Cretaceous–Palaeogene boundary, known for its famous iridium anomaly (Alvarez et al., 1980). The suffix -pristis from the Greek for ‘saw’ (entering zoological usage in this context via Cuvier, 1829), used in the extant holocentrid genera Myripristis and Pristilepis, and referring to the holocentrid affinity for bearing coarse squamation.

The specific name is in honour of David Parris, Curator Emeritus of Natural History at the New Jersey State Museum, for his discovery of the specimens described here, and in appreciation of his life-long devotion to the study of the North American fossil fauna.

Conclusions: 

†Iridopristis parrisi presents as an articulated skull and abdomen from the early Danian Hornerstown Formation of New Jersey, USA. Inclusion of the specimen in a phylogenetic analysis suggests that it is a stem-member of Holocentridae, along with the Ypresian-age †Berybolcensis and †Tenuicentrum. The new species possesses multiple characters that align it more closely to Cenozoic holocentroids than to Cretaceous holocentroids, including: a separate opening of the orbital branch of the supraorbital sensory canal, ventrolateral wings of the parasphenoid, an anterior ceratohyal with no foramen, and deep notches along the ventral margin of the anterior ceratohyal to accommodate branchiostegals. Character state optimization supports character state acquisitions prior to the origin of †Iridopristis parrisi that have previously been interpreted as derived states for the subclade Myripristinae: an alveolar platform expanded near the symphysis to overhang the lateral margin of the dentary, and a concave tooth gap at the mesial margin of the premaxilla. This finding necessitates a deeper examination of phenotypic synapomorphies to support the subfamily Myripristinae. Three-dimensionally preserved fossil fishes of Danian age are rare, and further excavation of the greensand formations along the mid-Atlantic of the USA may offer greater insight into the faunal composition and evolutionary dynamics during the critical early Palaeogene history of marine spiny-rayed fishes. 

James V. Andrews, Jason P. Schein and Matt Friedman. 2023. An earliest Paleocene squirrelfish (Teleostei: Beryciformes: Holocentroidea) and its bearing on the timescale of holocentroid evolution. Journal of Systematic Palaeontology. 2(1);  2168571. DOI: doi.org/10.1080/14772019.2023.2168571 

 x.com/kryptophanaron/status/1631727844991672331 

[Paleontology • 2025] Helmetia expansa Walcott, 1918 Revisited – New insights into the internal anatomy, moulting and phylogeny of Conciliterga

Helmetia expansa Walcott, 1918 

in Losso, Caron et Ortega-Hernández, 2025. 

DOI: doi.org/10.1080/14772019.2025.2468195 

 Reconstruction by Marianne Collins

Abstract

The trilobitomorphs are a megadiverse and ecologically versatile group of Paleozoic euarthropods that include the iconic trilobites, as well as non-biomineralized clades exclusively known from Konservat-Lagersttätten. The concilitergans, defined by the presence of a broad, variably effaced and flattened dorsal exoskeleton, have received comparatively little attention. This is particularly true for Helmetia expansa from the mid-Cambrian Burgess Shale (British Columbia) – the first chronologically reported species of Conciliterga, which was originally figured (based on a single specimen) by Walcott (1918). Here, we present the first comprehensive description of H. expansa based on all material available from the Burgess Shale, totalling 36 specimens housed at the Royal Ontario Museum and the Smithsonian Institution. The non-biomineralized dorsal exoskeleton is broad and flat, with a serrated margin throughout. The body consists of a cephalon with well-developed anterolateral spines, six thoracic tergites and a large pygidium bearing two pairs of lateral spines and a single terminal spine. The preserved appendages include short uniramous antennae followed by 15 pairs of homonomous and biramous limbs composed of a gracile endopodite and an exopodite with a broad lobe and thick lamellae. The digestive system consists of a straight gut tract, including a ‘J’-shaped foregut and five paired digestive glands on the anterior half of the body expressed as small and convex oblong structures with a submillimetric lamellar ultrastructure. Two specimens of H. expansa provide the first direct evidence of moulting in concilitergans. The lack of dorsal ecdysial sutures suggests a marginal moulting strategy similar to extant Xiphosura. A revised phylogeny of Trilobitomorpha supports Arthroaspis bergstroemi from the early Cambrian Sirius Passet of Greenland as the earliest branching concilitergan and prompts a new diagnosis for the clade. Our results inform the internal relationships within Conciliterga and formalize the families Helmetiidae (Helmetia, Rhombicalvaria, Haifengella and Kuamaia) and Tegopeltidae (Tegopelte, Skioldia, Saperion).

Keywords: Burgess Shale, Cambrian, Conciliterga, exceptional preservation, Helmetiida, moulting

Artiopoda Hou & Bergström, 1997

Trilobitomorpha Størmer, 1944

Conciliterga Hou & Bergström, 1997

Constituent taxa: Arthroaspis bergstroemi Stein et al., 2013; Helmetiida Novozhilov, 1960.

Order Helmetiida Novozhilov, 1960

Constituent taxa: Family Tegopeltidae Simonetta & Delle Cave, 1975; Family Helmetiidae Simonetta & Delle Cave, 1975.

Concilitergan diversity and relationships.
A, Arthroaspis bergstroemi, MGUH 30382, from the early Cambrian (Stage 3) Sirius Passet, Greenland. B, Helmetia expansa, USNM 83952, from the mid-Cambrian (Wuliuan) Burgess Shale, Canada. C, Kuamaia lata, CJHMD 00064, from early Cambrian (Stage 3) Chengjiang, China. D, Tegopelte gigas, USNM 189201, from the mid-Cambrian (Wuliuan) Burgess Shale, Canada.
E, simplified topology based on results from phylogenetic analyses herein which resolved Arthroaspis bergstroemi as an early-branching concilitergan.

 Holotype of Helmetia expansa USNM 83952, dorsal view.
A, Cross polarized light. B, Low angle light. C, Magnification of A showing cephalon. D, Magnification of A showing lamellae.

Abbreviations: cep, cephalon; anl, anterolateral spine; ant, antenna; asc, anterior sclerite; ey, eye; ex, exopodite; hyp, hypostome; lm, lamellae; mey, medial eyes; mg, midgut gland; opn, optical nerve; py, pygidium; rs, reniform structure; stn, sternite number; th, thorax.

Family Tegopeltidae Simonetta & Delle Cave, 1975

Constituent genera: Tegopelte Simonetta & Delle Cave, 1975; Skioldia Hou & Bergström, 1997; and Saperion Hou & Bergström, 1997.

...

Family Helmetiidae Simonetta & Delle Cave, 1975

Emended diagnosis: Concilitergans in which the thorax has tergites with non-effaced boundaries and well-developed pleural spines, and a pygidium with variable number of posterolateral spines and a medial terminal spine with a broad base.

Constituent genera: Helmetia Walcott, 1918; Rhombicalvaria Hou, 1987; Haifengella Zhao et al., 2014; Kuamaia Hou & Bergström, 1997.

Genus Helmetia Walcott, 1918

Type species: Helmetia expansa Walcott, 1918

 

 the Burgess Shale concilitergan Helmetia expansa.

 Reconstruction by Marianne Collins

Conclusion: 

We redescribe Helmetia expansa as one of the best-known concilitergans based on 36 specimens from the Burgess Shale. It has large anterolateral spines, a serrated margin, a six-segmented thorax and a large pygidium with two pairs of spines.

New material reveals insights into the preservation of non-biomineralized structures in H. expansa, including antennae, biramous appendages, optic structures and traces of digestive glands. Additionally, H. expansa acquired an adult exoskeletal morphology that at least doubled in size throughout ontogeny and provides rare direct evidence of moulting in a non-biomineralized Cambrian trilobitomorph.

New morphological characters and broader taxon sampling of Cambrian artiopodans clarifies the internal relationships within Conciliterga, which contains Arthroaspis bergstroemi from Sirius Passet and two major families Helmetiidae and Tegopeltidae, both represented in the Burgess Shale and Chengjiang Lagerstätten.

Sarah R. Losso, Jean-Bernard Caron and Javier Ortega-Hernández. 2025. Helmetia expansa Walcott, 1918 Revisited – New insights into the internal anatomy, moulting and phylogeny of Conciliterga. Journal of Systematic Palaeontology. 23(1); 2468195. DOI: doi.org/10.1080/14772019.2025.2468195  [04 Apr 2025]

 

[PaleoIchthyology • 2021] Jiangxialepis retrospina • The Oldest eugaleaspiform (Galeaspida) from the Silurian Fentou Formation (Telychian, Llandovery) of Wuhan, South China

Jiangxialepis retrospina Liu, Huang, Zong & Gong, 2021; 

 interpretative drawings of A, Shuyu zhejiangensis Pan, 1986; B, Jiangxialepis retrospina gen. et sp. nov.; C, Meishanaspis lehmani Wang, 1991.

DOI: doi.org/10.1080/14772019.2021.1883755 

  Researchgate.net/publication/349934424

 Abstract

A new genus of Eugaleaspidiformes (Galeaspida, Agnatha), Jiangxialepis gen. nov., is described from the Llandovery (Silurian) Fentou Formation from Wuhan, Hubei, South China. The new genus belongs to the family Shuyuidae, as evidenced by the splayed posterior supraorbital canals, absence of ‘U’-shaped median dorsal canals, and three lateral transverse canals issuing from the infraorbital canals. The new genus possesses a middle dorsal spine, which is found in eugaleaspidiforms for the first time. Jiangxialepis differs from other genera of Shuyuidae based on the following characteristics: presence of a middle dorsal spine, the anterior end of the median dorsal opening slightly disrupting the rostral margin of the head shield, large oval orbital openings, pineal opening level with the centre of the orbital opening, and seven lateral transverse canals on each side. The new genus is the first discovery of a eugaleaspidiform in the Fentou Formation, which extends the age of eugaleaspiforms to the middle Telychian and illuminates the early morphological conditions of the Eugaleaspidiformes. Cladistic analysis shows that the new genus is the most primitive group of Eugaleaspidiformes (Shuyuidae) and forms a trichotomy with Shuyu and Meishanaspis. We interpret Jiangxialepis as a sub-demersal fish that lived in the brackish waters of an estuarine-deltaic environment.

 

Keywords: Jiangxialepis, Shuyuidae, Eugaleaspiformes, Fentou Formation, Silurian, Wuhan, South China

Photographs and interpretative drawing of Jiangxialepis retrospina gen. et sp. nov.
A, internal mould of a complete head shield, BGEG-JXD-07; B, external mould of a complete head shield, BGEG-JXD-06; C, external mould of an incomplete head shield, BGEG-JXD-01; D-F, interpretative drawings of A-C, respectively; G, external mould of an incomplete head shield, BGEG-JXD-04; H, interpretative drawing of G; I, synthetic restoration.

Abbreviations: c, corneal processes; dcm, dorsal commissure; ic, inner corneal processes; ldc, lateral dorsal canal; ifc, infraorbital canal; ltc a-c , a to c lateral transverse canal; ltc 1-4 , first to fourth lateral transverse canal; md.o, median dorsal opening; md.s, median dorsal spine; orb, orbital opening; pi, pineal opening; soc 2 , posterior supraorbital canal.

 Comparison of shuyuids. A, Shuyu zhejiangensis (Liu et al. 2015); B, Jiangxialepis retrospina gen. et sp. nov.; C, Meishanaspis lehmani (modified after Gai et al. 2005).

Jiangxialepis retrospina 

 

Reconstruction of the ecological environment for the middle Telychian galeaspids from Wuhan in South China.
1, Jiangxialepis; 2, Hanyangaspis; 3, algae; 4, lingulids; 5, eurypteri.

Yi-Long Liu, Lie-Bin Huang, Rui-Wen Zong and Yi-Ming Gong. 2021. The Oldest eugaleaspiform (Galeaspida) from the Silurian Fentou Formation (Telychian, Llandovery) of Wuhan, South China. Journal of Systematic Palaeontology. 19(4); 253-264. DOI: doi.org/10.1080/14772019.2021.1883755 

  Researchgate.net/publication/349934424_The_oldest_eugaleaspiform_Galeaspida_from_the_Silurian_Fentou_Formation_of_Wuhan_South_China