[Paleontology • 2025] Gadusaurus aqualigneus • A New ichthyosaur from the Lower Jurassic of Portugal (Iberian Peninsula)

Gadusaurus aqualigneus 

 Sousa, Roldão, Ríos & Puértolas-Pascual, 2025

    

DOI: doi.org/10.4202/app.01199.2024

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Ichthyosaurs were a group of marine Mesozoic reptiles. Their presence in the Portuguese fossil record is scarce and ranges from the Sinemurian to the Toarcian. In this work we describe a new specimen—a nearly complete skull discovered in the Sinemurian of Praia de Água de Madeiros, São Pedro de Moel, Municipality of Marinha Grande (Portugal). This specimen represents the most complete and best preserved cranial remains from the Iberian Peninsula published to date. Phylogenetic analyses performed identified this specimen as a new genus and species, Gadusarus aqualigneus, the first to be identified in the Iberian Peninsula. The species is phylogenetically recovered as a baracromian ichthyosaur, part of the Neoichthyosauria and Parvipelvia clades.

Key words: Parvipelvia, Ichthyosauria, Gadusaurus aqualigneus , phylogeny, Sinemurian, São Pedro de Moel.

 Ichthyosaur reptile Gadusaurus aqualigneus gen. et sp. nov. (ML 2750) from from the Lower Jurassic of São Pedro de Moel (Marinha Grande, Portugal). Nearly complete skull in laterodorsal view. 

Ichthyopterygia Owen, 1859 

Ichthyosauria Blainville, 1835 

Parvipelvia Motani, 1999 

Neoichthyosauria Sander, 2000 

Thunnosauria Motani, 1999 

Baracromia Fischer et al., 2013

 Genus Gadusaurus nov.  

Type species: Gadusaurus aqualigneus sp. nov. 

Etymology: From combination of Latin gadu, codfish, and Ancient Greek, sauros, lizard; in reference to both the ichthyosaur fish-like body shape, and the proclivity for codfish in Portuguese cuisine. 

 

Gadusaurus aqualigneus sp. nov.  

 Etymology: From Latin aqua, water and lignum, wood; in reference to Água de Madeiros, which roughly translates to “water of woods”, the beach where the specimen was found. 

Holotype: ML 2750, nearly complete skull (Fig. 2), in a flattened state, the right side fully observable in lateral view, and elements of the left side observable in dorsal view. 

Type locality: Praia de Água de Madeiros, São Pedro de Moel, Municipality of Marinha Grande, (Portugal). 

Type horizon: Upper part of the Polvoeira Member of the Água de Madeiros Formation, upper Sinemurian (Lower Jurassic). 

Diagnosis.—Small-sized ichthyosaur, with an estimated length of approximately 2 m, diagnosed by the following combination of ambiguous synapomorphies: absence of a supranarial process in the premaxilla; and the parietal foramen being entirely surrounded by the frontals. Gadusaurus aqualigneus gen. et sp. nov. is also characterized by the following potential autapomorphies within Parvipelvia: presence of a subcircular depression in the lacrimal just below the posterior region of the external naris (Fig. 3C); big and well-developed elliptical internasal foramen with about 5 times bigger surface area than that of the parietal foramen (Fig. 3A); presence of a well-marked longitudinal groove on each side of the anterolateral region of the excavatio internasalis (Fig 3B).

João Pratas E Sousa, Isabel Morais Roldão, María Ríos, and Eduardo Puértolas-Pascual. 2025. A New ichthyosaur from the Lower Jurassic of Portugal (Iberian Peninsula). Acta Palaeontologica Polonica. 70(1); 179-192. DOI: doi.org/10.4202/app.01199.2024

  x.com/EduardoSuchus/status/1906793836375835069

[Paleontology • 2025] Xiphodracon goldencapensis • A New long and narrow-snouted ichthyosaur (Ichthyosauria: Leptonectidae) illuminates a complex faunal turnover during an undersampled Early Jurassic (Pliensbachian) interval

Xiphodracon goldencapensis 

 Lomax, Massare & Maxwell, 2025 

 

DOI: doi.org/10.1002/spp2.70038

Artwork by Bob Nicholls

Abstract

Ichthyosaurian faunas before and after the Pliensbachian stage of the Early Jurassic are known from numerous, often complete fossils. The two faunas are very different taxonomically, with only one of the pre-Pliensbachian genera, but none of the species, persisting into the post-Pliensbachian (Toarcian). Pliensbachian ichthyosaurs are rare, yet this interval represents a critical and poorly understood time in ichthyosaurian evolution just c. 10 myr after the end-Triassic mass extinction. Thus, a new ichthyosaur from the mid-Pliensbachian of the Dorset coast of the UK, the most complete ichthyosaur known from that stage, is significant. Xiphodracon goldencapensis gen. et sp. nov. is characterized by a distinct combination of characters and several autapomorphies, including: a unique lacrimal with prong-like projections on its anterior edge, a prefrontal with projections that interdigitate with the nasal and lacrimal, a wedge-shaped external naris with an anterodorsal constriction that forms a distinct foramen (shaped by the nasal, lacrimal and prefrontal), and a maxilla that forms almost the entire border of the external naris. Phylogenetic analyses indicate that X. goldencapensis is more closely related to the late Pliensbachian to Toarcian genus Hauffiopteryx than to earlier genera that continued into the Pliensbachian (e.g. Leptonectes, Ichthyosaurus), and forms a distinct clade (Hauffiopterygia nov.) within a monophyletic Leptonectidae. This indicates that a substantial faunal turnover in diversity occurred towards the end of the early Pliensbachian, leading to a major shift in composition towards a more typical Toarcian ichthyosaur fauna.

Keywords: Ichthyosauria, Pliensbachian, Leptonectidae, Lower Jurassic, faunal turnover, Xiphodracon

The holotype and only known specimen of the hauffiopterygian leptonectid, Xiphodracon goldencapensis (ROM VP52596) from Golden Cap, between Charmouth and Seatown, Dorset, UK.
 The skeleton is exposed in ventrolateral view. The skull has been fully prepared free of matrix whereas most of the skeleton is still in matrix. The left (upper) forefin has been prepared so that it is three-dimensionally preserved and projects upwards. Scale bar represents 20 cm.
Skull of  Xiphodracon goldencapensis (ROM VP52596).
Photograph (A) and interpretative illustration (B) in left lateral view. C, photograph of the right lateral view. Note the unusual, multi-prong projections on the anterodorsal margin of the lacrimal and similar but smaller interdigitating structures on the prefrontal (see also Fig. 4).

Abbreviations: an, angular; den, dentary; ju, jugal; la, lacrimal; mx, maxilla; n, nasal; p, parietal; pmx, premaxilla; po, postorbital; prf, prefrontal; ptf, postfrontal; qj, quadratojugal; sp, splenial; st, supratemporal. Scale bar represents 10 cm.

SYSTEMATIC PALAEONTOLOGY

ICHTHYOSAURIA de Blainville 1835

PARVIPELVIA Motani 1999a

LEPTONECTIDAE Maisch 1998

HAUFFIOPTERYGIA nov. 

Diagnosis: Mid-sized ichthyosaurs <3.5 m in length, characterized by a lack of contact between the nasal and postfrontal; participation of the prefrontal in the external narial opening; forefin with four digits; proximal limb elements polygonal; bicapitate dorsal ribs; lateral gastral elements extending at least two-thirds of the length of the dorsal region; and a rod-like ischium and pubis.

Genus Xiphodracon nov.

 

Derivation of name: Sword-like dragon. Xipho- derived from ancient Greek xiphos meaning ‘sword or sword shaped’ in reference to the long, narrow and sword-like snout, and -dracon, ancient Greek (drakōn) and Latin (dracō) for ‘dragon’, in reference to ichthyosaurs having been informally and colloquially referred to as ‘sea dragons’ for over 200 years.

 

Xiphodracon goldencapensis sp. nov.

 

Derivation of name: Sword-like dragon from Golden Cap. The species epithet goldencapensis refers to the location of discovery at Golden Cap, Dorset, England, UK.

Holotype: ROM VP52596, an almost complete skeleton comprising a three-dimensionally preserved skull, mandible and teeth, pectoral girdle, both forefins, pelvic girdle, parts of both hindfins, and most of the axial skeleton. A cast of ROM VP52596 is in the collections of the State Museum of Natural History Stuttgart, catalogued as SMNS 97790.

Type locality & horizon: East of Golden Cap, between Charmouth and Seatown, Dorset, UK, from the Early Jurassic, early Pliensbachian. Lias Group, Lower Lias Subgroup, Charmouth Mudstone Formation, Green Ammonite Member, Bed 122c (c. 1.5–2 m above Bed 121); Davoei Zone, Maculatum Subzone.

Diagnosis: A mid-sized, c. 3 m hauffiopterygian leptonectid with the following autapomorphies: anterodorsal border of triradiate lacrimal rugosely striated with prominent prong-like projections on its anterior edge; prefrontal anterior process with projecting structures that interdigitate with similar structures on nasal and dorsal lacrimal; posterodorsal foramen connected to the external naris; posterodorsal foramen formed by the nasal, prefrontal and lacrimal; small flange on the nasal and lacrimal forming a constriction that connects the foramen to the narial opening; anterodorsal part of the maxilla ‘split’ by the subnarial process of the premaxilla, creating dorsal and ventral processes; maxilla comprising almost entire ventral margin of naris, which is unique among Early Jurassic ichthyosaurs.

Artwork by Bob Nicholls

Dean R. Lomax, Judy A. Massare and Erin E. Maxwell. 2025. A New long and narrow-snouted ichthyosaur illuminates a complex faunal turnover during an undersampled Early Jurassic (Pliensbachian) interval. Papers in Palaeontology. DOI: doi.org/10.1002/spp2.70038 [09 October 2025] 

[Paleontology • 2025] Eurhinosaurus mistelgauensis • A new Eurhinosaurus Species (Ichthyosauria) from the Lower Jurassic (Toarcian) of Mistelgau (Bavaria, Southern Germany)

 Eurhinosaurus mistelgauensis

Spicher, Miedema, Heijne & Klein, 2025

DOI: doi.org/10.3897/fr.28.154203

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artwork by Andrey Atuchin / Urwelt-Museum Oberfranken

Abstract

Eurhinosaurus is a European Lower Jurassic longirostrine ichthyosaur, characterized by its remarkable overbite. Despite the long history of the genus, the taxonomy of Eurhinosaurus is still under debate, and its morphology is poorly understood. Over the past two decades, three specimens of Eurhinosaurus have been discovered in the Mistelgau clay pit in Bavaria, southern Germany, from Upper Toarcian layers. This makes these specimens the youngest stratigraphic occurrence of the genus Eurhinosaurus. The examined specimens include two nearly complete skeletons and a partial snout, preserved three-dimensionally in a semi-articulated state, with elements exposed in multiple orientations. The Mistelgau specimens exhibit clear morphological similarities to known Eurhinosaurus, confirming their affiliation to the genus based on numerous characteristics. However, the Eurhinosaurus specimens from Mistelgau exhibit notable differences in the basioccipital and rib morphology compared to known species. While not significant at the genus level, these distinctions allow recognition as a new species: Eurhinosaurus mistelgauensis sp. nov. These well-preserved fossils from Mistelgau further provide valuable insights into Eurhinosaurus morphology and significantly contribute to our understanding of this historically important ichthyosaur.

Key Words: 3D Preservation, pathology, parvipelvia, skull morphology, taphonomy, taxonomy

 Eurhinosaurus mistelgauensis sp. nov.

Paleoart by Andrey Atuchin 

(used with permission of the Urwelt-Museum Oberfranken)

 Gaël E. Spicher, Feiko Miedema, Jelle Heijne and Nicole Klein. 2025. A new Eurhinosaurus (Ichthyosauria) species from the Lower Jurassic (Toarcian) of Mistelgau (Bavaria, Southern Germany). Fossil Record. 28(2): 249-291. DOI: doi.org/10.3897/fr.28.154203

 x.com/SpicherGael/status/1971216591674319206

[Paleontology • 2025] The First gravid ichthyosaur from the Hauterivian (Early Cretaceous): a complete Myobradypterygius hauthali von Huene, 1927 excavated from the border of the Tyndall Glacier, Torres del Paine National Park, southernmost Chile

  

Myobradypterygius hauthali von Huene, 1927 

in Pardo-Pérez, Malkowski, Zambrano, Lomax, Martín, Kaluza, Ortíz, Andrés Marín, Villa-Martínez, Yurac, Cáceres, Zegers, Delgado, Scapini, Astete et Maxwell, 2025. 

DOI: doi.org/10.1080/02724634.2024.2445705

  facebook.com/UdeMagallanes 

  facebook.com: Mauricio Alvarez

ABSTRACT

Ichthyosaurs were pelagic marine reptiles with a global distribution through most of the Mesozoic. Cretaceous Ichthyosauria are mostly known from the northern hemisphere, although findings from the southern hemisphere have been reported from Australia, Argentina, Chile, and New Zealand. Despite these findings that have contributed to knowledge of the clade, there is still a dearth of information about the evolution, phylogenetics, and ecology of Cretaceous ichthyosaurs from the Southernmost Pacific margin of Gondwana. A Lower Cretaceous locality next to the Tyndall Glacier, inside Torres del Paine National Park, southernmost Chile, has yielded 87 ichthyosaur skeletons to date. Most of the specimens recorded from this area are complete and articulated, however, they are affected by recent weathering and the constant erosion. Here we describe a complete platypterygiine ichthyosaur, which we provisionally assign to Myobradypterygius hauthali von Huene, 1927. The specimen was excavated from the border of the glacier in Patagonia during March and April 2022 and corresponds to the first complete excavated ichthyosaur from Chile. This specimen additionally preserves gastrointestinal contents and is the only Hauterivian (131 Ma) ichthyosaur documented to date containing the articulated skeleton of a preserved fetus. This research increases the knowledge of the paleobiology of the species. In addition to morphology, it contributes information regarding paleoecology and paleopathology, diet, and reproduction in M. hauthali, a taxon potentially restricted to the Pacific margin of Gondwana.

 

  

 

Judith M. Pardo-Pérez, Matthew Malkowski, Patricio Zambrano, Dean R. Lomax, Cristina Gascó Martín, Jonatan Kaluza, Héctor Ortíz, Andrés Pérez Marín, Rodrigo Villa-Martínez, Marko Yurac, Miguel Cáceres, Aymara Zegers, Javiera Delgado, Francisca Scapini, Catalina Astete and Erin E. Maxwell. 2025. The First gravid ichthyosaur from the Hauterivian (Early Cretaceous): a complete Myobradypterygius hauthali von Huene, 1927 excavated from the border of the Tyndall Glacier, Torres del Paine National Park, southernmost Chile. Journal of Vertebrate Paleontology. e2445705. DOI: doi.org/10.1080/02724634.2024.2445705 [25 Feb 2025]

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  facebook.com/DeanRLomax/posts/1176590717805230

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[Paleontology • 2024] Validity of Myobradypterygius hauthali von Huene, 1927 (Ichthyosauria: Ophthalmosauria) from the Early Cretaceous of Chile and Argentina

Myobradypterygius hauthali von Huene, 1927

in Pardo-Pérez, Zambrano, Malkowski, Lomax, Villa-Martínez, Stinnesbeck, Frey, Scapini, Gascó et Maxwell, 2024. 

DOI: 10.1093/zoolinnean/zlae106 

 facebook.com/DeanRLomax

 

Abstract

Early Cretaceous ichthyosaurs were globally distributed pelagic marine reptiles, but many remains are fragmentary, creating a Northern Hemisphere diversity bias. A rich Hauterivian locality near the Tyndall Glacier inside Torres del Paine National Park in southern Chile yields important new data regarding ichthyosaurian diversity along the Pacific margin of Gondwana. These new data will contribute to clarifying questions regarding ichthyosaur taxonomy and the palaeobiogeographical relationships between the southern Gondwanan and Northern Hemisphere ichthyosaur groups during the Early Cretaceous. Here, we describe three new ichthyosaur specimens from this locality. Two of them are referred to Myobradypterygius hauthali, expanding the distribution of this species from the Barremian of Argentina to the Hauterivian of the Chilean Patagonia. This material shows that M. hauthali differs from Platypterygius platydactylus in forefin construction and scapular morphology, supporting its classification as a separate genus within Platypterygiinae. The third specimen is a large-bodied indeterminate ophthalmosaurine ichthyosaur. This record represents the southernmost record of Ophthalmosaurinae and the first occurrence of this group from the Cretaceous of the Southern Hemisphere. These discoveries show that ophthalmosaurines and platypterygiines continued to occur sympatrically in southernmost Gondwana during the Early Cretaceous, expanding the pattern documented in Europe to the Pacific region.

Ichthyosauria, Early Cretaceous, Gondwana, Patagonia

Judith Pardo-Pérez, Patricio Zambrano, Matthew Malkowski, Dean Lomax, Rodrigo Villa-Martínez, Wolfgang Stinnesbeck, Eberhard Frey, Francisca Scapini, Cristina Gascó and Erin E Maxwell. 2024. Validity of Myobradypterygius hauthali von Huene, 1927 (Ichthyosauria: Ophthalmosauria) from the Early Cretaceous of Chile and Argentina. Zoological Journal of the Linnean Society. 202(2); zlae106. DOI: doi.org/10.1093/zoolinnean/zlae106

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https://archiv.ub.uni-heidelberg.de/volltextserver/20000/

[Paleontology • 2024] Platypterygius elsuntuoso • A New Species of Platypterygius (Ichthyosauria: Ophthalmosauridae) from the lower Barremian of Colombia and Assessment of the Species Composition of the Genus

Platypterygius elsuntuoso 

Páramo-Fonseca, Benavides-Cabra & Garavito-Camacho, 2024 

 

DOI: 10.15446/esrj.v28n2.112332

 

Abstract  

In this paper, we describe a new ophthalmosaurid specimen found in the lower Barremian beds of the Paja Formation at Villa de Leiva, Boyacá, Colombia. The specimen represents a new species of Platypterygius, P. elsuntuoso sp. nov. defined by three unique features within the genus: a small ventral peg in the anterior ventral border of the extracondylar area of the basioccipital; a supratemporal groove in the quadrate; and a shallow neck at the base of the acellular cementum ring on the teeth root. In support of our taxonomic determination, in this contribution we also assess the species composition of the genus Platypterygius, comparing the known anatomy of the type species P. platydactylus with that of the other species previously assigned to the genus. We found that a great morphological affinity in the forelimb of the species P. americanus, P. australis, P. hercynicus, and P. sachicarum (lower Barremian to lower Cenomanian) with that of the type species (Aptian) is unquestionable and differentiate them from all other ophthalmosaurids. Three new diagnostic features (synapomorphies of the genus) support their inclusion in Platypterygius. Consequently, the genus name “Kyhytysuka”, recently proposed to differentiate P. sachicarum from the genus Platypterygius is here rejected. A careful comparison of the cranial characteristics of Platypterygius specimens preserving associated cranial and fin remains demonstrate that Platypterygius is a genus distinguishable from other ophthalmosaurids not only by a typical forelimb but also by a particular combination of skull features. In this context, the skull morphology of “Simbirskiasaurus” concurs with that defining Platypterygius and its minor differences are not sufficient to support its generic distinction. The morphological comparisons and our phylogenetic analysis show the new species P. elsuntuoso more closely related to the Colombian species P. sachicarum than to other species of Platypterygius. Given that the new species came from the lower Barremian and P. sachicarum came from the upper Barremian, the minor differences in dentition found between the two species suggest a speciation by adaptation to new food sources in the Cretaceous epicontinental sea of Colombia.

Keywords: Ophthalmosauridae; Platypterygius; Barremian; Colombia

Platypterygius elsuntuoso sp. nov., holotype FCG-CBP-28.
Photographs and interpretative drawings of the specimen in A, right lateral view, B, left lateral view before extracting the basioccipital and the left coracoid, and C, dorsal view. Grey: sediment; black: breakage space; dots: missing surface.

Abbreviations: aen, anterior external narial aperture; an, angular; ar, articular; at, atlas; ax, axis; bo, basioccipital; bs, basisphenoid; d, dentary; es, sclerotic plates; f, frontal; fj, facet for the jugal; hy, hyoid; j, jugal; la, lacrimal; lan, left angular; lar, left articular; lcor, left coracoid; ld, left dentary; ln, left nasal; lpt, left pterygoid; lsa, left surangular; lsp, left splenial; mx, maxilla; n, nasal; np, nasal process; ns, neural spine; oe, occipital element; p, parietal; pal, palatine; par, prearticular; pf, parietal foramen; ph, phalange; pmx, premaxilla; po, postorbital; pof, postfrontal; prf, prefrontal; ps, parasphenoid; pt, pterygoid; q, quadrate; qj, quadratojugal; rb, rib; rar, right articular; rn, right nasal; rpar, right prearticular; rpt, right pterygoid; rst, right supratemporal; rstp, right stapes; sa, surangular; saf, surangular fossa; sp, splenial; st, supratemporal; sym, posterior end of the symphysis; v, vomer; vc, vertebral centrum. 

Scale bars = 100 mm.

ICHTHYOSAURIA de Blainville, 1835

OPHTHALMOSAURIDAE Baur, 1887

Platypterygius elsuntuoso sp. nov. 

Holotype and only known specimen: FCG-CBP-28. A skull lacking the anterior portion of the snout; some disarticulated axial elements, incomplete left coracoid, and a few phalanges.

Type locality and horizon: Loma La Cabrera, northwest of Villa de Leiva, Boyacá. Paja Formation, Arcillolitas abigarradas Member, segment A or B of Etayo-Serna (1968a), lower Barremian (Benavides-Cabra et al., 2023) (Fig. 1).

Diagnosis: P. elsuntuoso is distinguished from other species of Platypterygius by the following unique features: 1- The anterior ventral border of the extracondylar area of the basioccipital bears a small ventral peg anteroventrally directed (Shared with Plutoniosaurus, Zverkov pers. comm.), which fits into a posteroventral depression found in the basisphenoid; 2- Quadrate with supratemporal groove dorsal to the stapedial foramen (Shared with Plutoniosaurus Zverkov pers. comm.; and Undorosaurus see Zverkov & Efimov, 2019) ; and 3- Root of teeth with a shallow neck at the base of the acellular cementum ring.

...

Derivation of name: from “el suntuoso”, Spanish for “the sumptuous”, nickname used by C. B. Padilla, deceased founder of the FCG and CIP, when referring to the specimen.

 

María E. Páramo-Fonseca, Cristian D. Benavides-Cabra and Renzo A. Garavito-Camacho. 2024. A New Species of Platypterygius (Ophthalmosauridae) from the lower Barremian of Colombia and Assessment of the Species Composition of the Genus. Earth Sciences Research Journal.  28(2); DOI: doi.org/10.15446/esrj.v28n2.112332

  revistas.unal.edu.co/index.php/esrj/article/view/112332

[Paleontology • 2024] Postcranial Anatomy of Besanosaurus leptorhynchus (Reptilia: Ichthyosauria) from the Middle Triassic Besano Formation of Monte San Giorgio (Italy/Switzerland), with Implications for Reconstructing the Swimming Styles of Triassic Ichthyosaurs

Besanosaurus leptorhynchus Dal Sasso & Pinna, 1996
Artistic reconstruction (based on BES SC 999) catching a Phragmoteuthis. 

in Bindellini, Wolniewicz, Miedema, Dal Sasso et Scheyer, 2024.

DOI: 10.1186/s13358-024-00330-9 

 x.com/ASWolniewicz

 Artwork by Alessio Ciaffi

Abstract

Besanosaurus leptorhynchus Dal Sasso & Pinna, 1996 was originally described on the basis of a single complete fossil specimen excavated near Besano (Italy). However, a recent taxonomic revision and re-examination of the cranial osteology allowed for the assignment of five additional specimens to the taxon. Here, we analyse, describe and discuss the postcranial anatomy of Besanosaurus leptorhynchus in detail. The size of the specimens examined herein ranged from slightly more than one meter to eight meters. Overall, several diagnostic character states for this taxon are proposed, demonstrating a mosaic of plesiomorphic and derived features. This is best exemplified by the limbs, which show very rounded elements in the forelimbs, and pedal phalanges with retained rudimentary shafts. We suggest that the widely spaced phalanges in the forefins of Besanosaurus leptorhynchus were embedded in a fibrocartilage-rich connective tissue, like in modern cetaceans. We also review the similarities of Besanosaurus with Pessopteryx and Pessosaurus, allowing us to conclude that Besanosaurus is not a junior synonym of either of the two taxa. Lastly, to test the swimming capabilities of Besanosaurus leptorhynchus, we expanded on a previously published study focussing on reconstructing the swimming styles of ichthyosaurs. Besanosaurus leptorhynchus was found to possess a peculiar locomotory mode, somewhat intermediate between anguilliform swimmers, such as Cymbospondylus and Utatsusaurus, and some shastasaur-grade (e.g., Guizhouichthyosaurus) and early-diverging euichthyosaurian (e.g., Californosaurus) ichthyosaurs. Based on our results, we furthermore suggest that mixosaurids acquired their characteristic body profile (dorsal fin and forefins that are distinctly enlarged compared to the hindfins) independently and convergently to the one that later appeared in Parvipelvia. Moreover, the different swimming styles inferred for Cymbospondylus, Mixosauridae, and Besanosaurus strengthen the earlier hypothesis of niche partitioning among these three distinct ichthyosaur taxa from the Besano Formation.

Keywords: Ichthyosauria, Shastasauridae, Middle Triassic, Besano Formation, Monte San Giorgio, Postcranial anatomy, Osteology, Phylogeny, Swimming style, Marine reptiles

Artistic reconstruction of Besanosaurus leptorhynchus (based on BES SC 999) catching a Phragmoteuthis. Two individuals of Mixosaurus and a shoal of the ammonoid Ceratites can be seen in the background to the left of Besanosaurus leptorhynchus. Some ammonoids of the genus Serpianites are visible swimming around the large ichthyosaur and a single individual of the same ammonoid is depicted in the foreground on the right, along with other specimens of Phragmoteuthis.

 Artwork by Alessio Ciaffi

 

Gabriele Bindellini, Andrzej S. Wolniewicz, Feiko Miedema, Cristiano Dal Sasso and Torsten M. Scheyer. 2024. Postcranial Anatomy of Besanosaurus leptorhynchus (Reptilia: Ichthyosauria) from the Middle Triassic Besano Formation of Monte San Giorgio (Italy/Switzerland), with Implications for Reconstructing the Swimming Styles of Triassic Ichthyosaurs. Swiss Journal of Palaeontology. 143: 32. DOI: doi.org/10.1186/s13358-024-00330-9

  x.com/ASWolniewicz/status/1833548304040317084

[Paleontology • 2024] Ichthyotitan severnensis • The Last Giants: New Evidence for Giant Late Triassic (Rhaetian) ichthyosaurs from the UK

 

 Ichthyotitan severnensis 

Lomax, de la Salle, Perillo, Reynolds, Reynolds & Waldron, 2024

DOI: 10.1371/journal.pone.0300289

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Abstract

Giant ichthyosaurs with body length estimates exceeding 20 m were present in the latest Triassic of the UK. Here we report on the discovery of a second surangular from the lower jaw of a giant ichthyosaur from Somerset, UK. The new find is comparable in size and morphology to a specimen from Lilstock, Somerset, described in 2018, but it is more complete and better preserved. Both finds are from the uppermost Triassic Westbury Mudstone Formation (Rhaetian), but the new specimen comes from Blue Anchor, approximately 10 km west along the coast from Lilstock. The more complete surangular would have been >2 m long, from an individual with a body length estimated at ~25 m. The identification of two specimens with the same unique morphology and from the same geologic age and geographic location warrants the erection of a new genus and species, Ichthyotitan severnensis gen. et sp. nov. Thin sections of the new specimen revealed the same histological features already observed in similar giant ichthyosaurian specimens. Our data also supports the previous suggestion of an atypical osteogenesis in the lower jaws of giant ichthyosaurs. The geological age and giant size of the specimens suggest shastasaurid affinities, but the material is too incomplete for a definitive referral. Ichthyotitan severnensis gen. et sp. nov., is the first-named giant ichthyosaur from the Rhaetian and probably represents the largest marine reptile formally described.

Comparison of the holotype (BRSMG Cg3178, A and C right surangular, BAS specimen) and referred specimen (BRSMG Cg2488, B and D left surangular, Lilstock specimen) of Ichthyotitan severnensis gen. et sp. nov. To ease comparison, A and C have been reversed.

Systematic palaeontology

Ichthyopterygia Owen, 1840

Ichthyosauria de Blainville, 1835

?Merriamosauria Motani, 1999

?Shastasauridae Merriam, 1902

Ichthyotitan severnensis gen. et sp. nov. 

Diagnosis: Giant, probable shastasaurid ichthyosaur distinguished by the presence of the following unique characters of the surangular: upturned, almost 90 degree angle bend at posterior end; subcircular cross section morphology of the shaft at the position of the coronoid, oblong in Shonisaurus; minor eminence of coronoid process in lateral view, compared with prominent projection in Shonisaurus; bulbous coronoid process displaced laterally and only occupying half of the width of the dorsal surface; massively developed dorsoventral M.A.M.E. ridge; spatulate shaped posterior end; and possibly dorsoventral height of posterior end in adults being more than 20% larger than in either Shonisaurus popularis or Shonisaurus sikanniensis.

Holotype: BRSMG Cg3178, a large right surangular comprising the posterior end and parts of the middle and anterior sections.

Referred material: BRSMG Cg2488, a large left surangular comprising the posterior end and a portion of the shaft.

Type locality and horizon: The type specimen was collected from the Upper Triassic Westbury Mudstone Formation (latest Rhaetian) at Blue Anchor, Somerset, UK. The referred specimen was collected from the Upper Triassic Westbury Mudstone Formation (latest Rhaetian) 0.8 m below the junction with the Cotham Formation, at Lilstock, Somerset, UK.

Etymology: Giant fish lizard of the Severn. Ichthys derived from Greek meaning fish, taken from ichthyosaur meaning “fish lizard”, and -titan (Greek for giant), after the large size. Severn after the River Severn Estuary, Somerset, UK, where the remains were discovered and Latin -ensis pertaining to the location.

 

 Dean R. Lomax, Paul de la Salle, Marcello Perillo, Justin Reynolds, Ruby Reynolds and James F. Waldron. 2024. The Last Giants: New Evidence for Giant Late Triassic (Rhaetian) ichthyosaurs from the UK. PLoS ONE. 19(4): e0300289. DOI: 10.1371/journal.pone.0300289

  facebook.com/DeanRLomax/posts/938383304959307

  

[Paleontology • 2024] The Dinosaurs that weren’t: Osteohistology supports Giant Ichthyosaur Affinity of enigmatic large Bone Segments from the European Rhaetian

in Perillo​ & Sander, 2024.

DOI: 10.7717/peerj.17060  

www.uni-bonn.de

Abstract

Very large unidentified elongate and rounded fossil bone segments of uncertain origin recovered from different Rhaetian (Late Triassic) fossil localities across Europe have been puzzling the paleontological community since the second half of the 19th century. Different hypotheses have been proposed regarding the nature of these fossils: (1) giant amphibian bones, (2) dinosaurian or other archosaurian long bone shafts, and (3) giant ichthyosaurian jaw bone segments. We call the latter proposal the ‘Giant Ichthyosaur Hypothesis’ and test it using bone histology. In presumable ichthyosaur specimens from SW England (Lilstock), France (Autun), and indeterminate cortical fragments from Germany (Bonenburg), we found a combination of shared histological features in the periosteal cortex: an unusual woven-parallel complex of strictly longitudinal primary osteons set in a novel woven-fibered matrix type with intrinsic coarse collagen fibers (IFM), and a distinctive pattern of Haversian substitution in which secondary osteons often form within primary ones. The splenial and surangular of the holotype of the giant ichthyosaur Shastasaurus sikanniensis from Canada were sampled for comparison. The results of the sampling indicate a common osteohistology with the European specimens. A broad histological comparison is provided to reject alternative taxonomic affinities aside from ichthyosaurs of the very large bone segment. Most importantly, we highlight the occurrence of shared peculiar osteogenic processes in Late Triassic giant ichthyosaurs, reflecting special ossification strategies enabling fast growth and achievement of giant size and/or related to biomechanical properties akin to ossified tendons.

A reconstruction of a gigantic ichthyosaur - floating dead on the surface of the ocean. Remains of ichthyosaurs have been found in ocean sediment in various places around Europe.

 Image: Marcello Perillo/University of Bonn

Conclusions: 

Paleohistology can be a powerful tool for determining the taxonomic affinity of fragmentary bone specimens, as has been demonstrated in dinosaur studies previously (e.g., Garilli et al., 2009; Hurum et al., 2006). However, paleohistology can also be used to show that dinosaur-sized fragmentary bones do not belong to dinosaurs at all. Our study does just that, ruling out Sauropodomorpha and Stegosauria as possible sources of the mysterious large bone segments and fragments found in the European Rhaetian, thus rejecting the Dinosaur Hypothesis and instead supporting the Giant Ichthyosaur Hypothesis laid out by Lomax et al. (2018).

....

Marcello Perillo​ and P Martin Sander. 2024. The Dinosaurs that weren’t: Osteohistology supports Giant Ichthyosaur Affinity of enigmatic large Bone Segments from the European Rhaetian.  PeerJ. 12:e17060. DOI: 10.7717/peerj.17060

Do some mysterious bones belong to gigantic ichthyosaurs?

A study sheds light on a mystery that has puzzled paleontologists for 150 years

  www.uni-bonn.de/en/news/072-2024

[Paleontology • 2023] Idahocolumbites phatthalungensis • Olenekian (Early Triassic) Ammonoids and Conodonts from southern Thailand

Idahocolumbites phatthalungensis Thongterm & Shigeta, 

in Tongtherm, Shigeta, Sardsud, Asato, Maekawa, Haga, Agematsu et Sashida, 2023

National Museum of Nature and Science Monographs. 54. 

 kahaku.go.jp/english/research/publication/monograph/v54.html 

 facebook.com/Tongtherm

Abstract 

We document an extensive biostratigraphic investigation of a section of the Phukhaothong Dolomite Member of the marine Triassic Chaiburi Formation (part of the Sibumasu [or Shan-Thai] Block), which is exposed on the north side of an isolated mountain at Khao Thong in the Phatthalung area of southern Thailand. The 104 m+ thick section, consisting of bedded to massive, light grey dolomite, contains ammonoids in the middle to upper parts, and conodonts occur in abundant throughout the section. Seven distinct early Spathian (late Olenekian) ammonoid assemblages, a late Smithian (early Olenekian) conodont zone and three early Spathian conodont zones are recognized in ascending order as follows: ammonoids-Columbites sp. indet. beds, Arctomeekoceras? sp. indet. beds, Tirolites sp. indet. B beds, Tirolites sp. indet. C beds and Tirolites sp. indet. D bed in the Tirolites-Columbites Zone, and the Idahocolumbites cheneyi beds and Idahocolumbites phatthalungensis beds in the Idahocolumbites Zone; conodonts-late Smithian, Hadrodontina aequabilis-Staeschegnathus perrii Zone, early Spathian Icriospathodus crassatus Zone, Triassospathodus symmetricus-Novispathodus anhuiensis Zone and Novispathodus sp. I-Novispathodus sp. J Zone. The age of the primitive ichthyopterygian Thaisaurus chonglakmanii collected from the Idahocolumbites cheneyi beds is constrained to the early Spathian, thus suggesting it is the oldest known ichthyopterygian, because the range of Marcouxia and Idahocolumbites is limited to the Columbites parisianus Subzone of the lower Spathian in the western USA. The Spathian ammonoid faunas exhibit a very strong relationship with other Tethyan as well as eastern Panthalassa faunas in the low paleolatitudes, but bear very little or no relationship with middle and higher latitudinal faunas, suggesting the existence of a strong latitudinal diversity gradient during the Spathian. Late Smithian and early Spathian conodont faunas also exhibit a strong relationship with low paleolatitudinal faunas. Fifty-eight taxa (ammonoids: 26, conodonts: 32) are documented and one new ammonoid species, i.e., Idahocolumbites phatthalungensis, is described.

Keywords: ammonoids, biostratigraphy, Chaiburi Formation, conodonts, Early Triassic, Olenekian,

Phatthalung, Smithian, Spathian, Thailand.

 

 Idahocolumbites phatthalungensis

  Kittichai Tongtherm, Yasunari Shigeta, Apsorn Sardsud, Kaito Asato, Takumi Maekawa, Takuma Haga, Sachiko Agematsu and Katsuo Sashida. 2023. Olenekian (Early Triassic) Ammonoids and Conodonts from southern Thailand. National Museum of Nature and Science Monographs. 54.

  kahaku.go.jp/english/research/publication/monograph/v54.html

  facebook.com/Tongtherm/posts/6166523333381548

หมวดหินชัยบุรี ในยุคไทรแอสซิก ที่พบใน จ.พัทลุง 

ชั้นหินบริเวณเขาทองอยู่ในช่วงรอยต่อของต้นยุคไทรแอสซิก อายุย่อย Smithian-Spathian ซึ่งตรงกับเหตุการ Smithian-Spathian boundary (SSB) ที่เป็นช่วงตรวจเจอปริมาณคาร์บอนสะสมเป็นจำนวนมากในทะเลส่วนหนึ่งเป็นผลมาจากการปะทุของลาวา ซึ่งทำให้เกิดการสูญพันธุ์ครั้งใหญ่ช่วงสิ้นยุคเพอร์เมียน (P–T extinction event) ที่กว่าสิ่งมีชีวิตจะฟื้นตัวกลับมาใช้เวลานานมาก ทั้งนี้กลุ่มแอมโมนอยด์และโคโนดอนต์เป็นกลุ่มที่ฟื้นตัวเร็วกว่ากลุ่มอื่น โดยในครั้งนี้สามารถกำหนด Biozone ของหมวดหินนี้จากฟอสซิลได้และเทียบเคียงได้กับชั้นหินเดียวกันทั่วโลก ที่เราพบอยู่ประมาณ 33 แหล่งเท่านั้น

งานครั้งนี้พบซากดึกดำบรรพ์ทั้งสิ้น 58 ชนิด เป็นแอมโมนอยด์ 26 ชนิด โคโนดอนต์ 32 ชนิด และนอกจากนี้เรายังพบแอมโมนอยด์ชนิดใหม่ทางวิทยาศาสตร์ คือ Idahocolumbites phatthalungensis ไอดาโฮโคลัมไบเทส พัทลุงเอนซิส โดยตั้งชื่อตามชื่อจังหวัดพัทลุง