Uragasaurus kalasinensis: A new species of Mamenchisaurid Sauropod from the Late Jurassic of northeastern Thailand.

The Mamenchisaurids were a group of non-Neosauropod Sauropods (i.e. outside the largest grouping of Sauropods) which formed a significant part of the fauna of East Asia during the Middle and Late Jurassic. They can be distinguished by highly pneumatised and elongated cervical vertebrae, as well as procoelous vertebrae on the front part of the caudal spine (procoelous vertebrae have a convex forward disk and a concave rear disk), which were distinctive during the Jurassic, but evolved convergently in several Neosauropod groups during the Cretaceous. 

Most known Mamenchisaurids come from China, and for a long time they were thought to be restricted to that country. However, in 2005 fragmentary remains attributed to the group were recovered from the Middle to Late Jurassic Khlong Min Formation of Krabi Province in southern Thailand. In 2013, further fragmentary remains were found in the Late Jurassic to Early Cretaceous Phu Kradung Formation of northeastern Thailand, and in 2019 a new species of Mamenchisaurid, Wamweracaudia keranjei, was described on the basis of a partial skeleton from the Late Jurassic Tendaguru Formation of southeastern Tanzania, establishing the presence of the group in Africa.

In a paper published in the journal Scientific Reports on 8 July 2026, Apirut Nilpanapan of the Department of Biology at Mahasarakham University, Sita Manitkoon of the Palaeontological Research and Education Centre and Vertebrate Palaeontology and Evolution Research Unit at Mahasarakham University, Varavudh Suteethorn of the Khon Kaen Geopark Association, and Komsorn Lauprasert also of the Department of Biology and Evolution Research Unit at Mahasarakham University, describe a new species of Mamenchisaurid Sauropod from the Phu Kradung Formation of northeastern Thailand.

The new species is named on the basis of material collected from the Phu Noi Locality, which is in the village of Ban Din Chi in the Kham Muang District of Kalasin Province, in the northeast of Thailand. Here an outcrop of the Phu Kradung Formation has produced one of the most diverse non-marine Vertebrate fossil assemblages in Southeast Asia. The Phu Kradung Formation comprises a series of sandstones, siltstones, and mudstones laid down in a fluvial environment, within a continental basin. 

Locality map and section diagram of Phu Noi Locality. (a) Map of Thailand; (b) location of Phu Noi Locality and the distribution of Phu Kradung Formation, the northeastern region with the outline of Kalasin Province; (c) diagrammatic section of Phu Noi. Nilpanapan et al. (2026).

The precise age of the Phu Kradung Formation is unknown, as it lacks any radiometrically datable horizons. However, regional stratigraphic correlations, Vertebrate assemblages, and detrital zircon data suggest that it is of Late Cretaceous origin, possibly with the uppermost part of the formation extending into the earliest Cretaceous.

The Phu Noi outcrop comprises numerous channel horizons formed within a braided river, rather than horizontal layers extending across the whole site. It has three fossil-bearing horizons. The lowest of these is a grey conglomeratic sandstone laid down in a channel bottom. About 10 m above this, the middle horizon is a brownish-purple and greenish-grey sandy siltstone and mudstone. At the same level as this, but about 400 m to the southwest, the upper horizon is a greyish siltstones within proximal floodplain deposit.

The specimen from which Nilpanpan et al. describe the new species comes from the middle horizon, which is particularly rich in Vertebrate remains, having previously yielded Hybodont Sharks,  Ginglymodian Fish, Lungfish, Eucryptodiran Turtles, Teleosaurid Crocodyliformes, and Neornithischian Dinosaurs, and with Brachyopid Temnospondyl, Rhamphorynchoidea Pterosaur, Tyrannosauroid and Metriacanthosaurid Theropod specimens currently being studied. This faunal assemblage shows a strong affinity to the Late Jurassic and earliest Cretaceous faunas of the Junggar, Turpan, and Sichuan basins of China.

The new species is named Uragasaurus kalasinensis, where 'Uragasaurus' derives from 'Uraga' (उरग) the Sanskrit word for Snake, in reference to the long, serpentine, neck of Sauropod Dinosaurs, plus '-saurus' (σαύρος), the Greek for Lizard, a common suffix in Dinosaur names, and 'kalasinensis' means 'from Kalasin' in reference to the province where the specimen was discovered. 

Uragasaurus kalasinensis is described from a single isolated anterior dorsal vertebra (PRC 460), from the Phu Noi locality, which is housed in the collection of the Palaeontological Research and Education Centre at Mahasarakham University. A number of other Sauropod elements were found close to this specimen in the same level, which Nilpanpan et al. refer to Uragasaurus kalasinensis. However, because these elements cannot be assigned to the same original Animal with 100% confidence, and they do not have overlapping diagnostic features, they are not included in the formal description of the species. This material includes two anterior dorsal neural arches (KS 34-581 & KS 34-586), a left coracoid (KS 34-587), a left fibula (KS 34-588), a middle cervical vertebra (KS 34-602a), a right cervical rib (KS 34-602b), a middle-to-posterior dorsal vertebra (KS 34-692), and a posterior dorsal vertebra (PN 13-23).

Holotype of Uragasaurus kalasinensis (PRC 460) and associated materials in the quarry map. PRC 460 Anterior dorsal vertebra in anterior view (a), KS 34-581 anterior dorsal neural arch in anterior view (b), KS 34-602a middle cervical vertebra in ventral view (c), KS 34-586 anterior dorsal neural arch in anterior view, attached by KS 34-588 fibula (d), KS 34-587 coracoid in lateral view (e), KS 34-602b right cervical rib in lateral view (f). Quarry map showing the spatial distribution of the holotype and associated materials from the Phu Noi Locality (g). PRC 460, representing the new taxon Uragasaurus kalasinensis, is indicated in red. Associated Sauropod elements include KS 34-586, KS 34-587, KS 34-588, and KS 34-602a–b, highlighted in yellow, green, blue, purple, and pink, respectively. The inset shows a close-up of the excavation grid highlighting the relative positions of the holotype and nearby associated materials. Each grid square represents 0.75 × 0.75 m. Nilpanpan et al. (2026).

The anterior dorsal vertebra assigned to Uragasaurus kalasinensis has a prominent, elongated teardrop-shaped pneumatic fossae on the distal portion of the transverse processes, intraprezygapophyseal laminae meeting ventromedially to form a Y-shaped configuration in anterior view, incorporating a single vertical intraprezygapophyseal lamina, and a shallow, subtriangular pleurocoel lacking an internal septum. 

The holotype anterior dorsal vertebra of Uragasaurus kalasinensis (PRC 460) in anterior (a) and posterior (b) views. Digital rendering of the specimen in anterior (c), posterior (d), right lateral (e), left lateral (f), dorsal (g), and ventral (h) views. Asterisk refers to an autapomorphic character. The blue highlight indicates the pneumatic fossa and pleurocoel. Abbreviations: Cpol, centropostzygapophyseal lamina; cprl, centroprezygapophyseal lamina; di, diapophysis; ns, neural  spine; pa, parapophysis; pcdl, posterior centrodiapophyseal lamina; pl, pleurocoel; pnfo, pneumatic  fossa; po, postzygapophysis; podl, postzygodiapophyseal lamina; ppdl, paradiapophyseal lamina; prdl, prezygodiapophyseal lamina; posl, postspinal lamina; prsl, prespinal lamina; spof, spinopostzygapophyseal fossa; spol, spinopostzygapophyseal lamina; sprf, spinoprezygapophyseal fossa; sprl, spinoprezygapophyseal  lamina; stprl, single interprezygapophyseal lamina; tp, transverse process; tpol, intrapostzygapophyseal lamina;  tprl, intraprezygapophyseal lamina. Nilpanpan et al. (2026).

A computed tomography of specimen PRC 460 showed that its centrum has a camellate internal pneumatic structure composed of numerous small, irregular chambers separated by thin bony septa, although it was not possible to accurately measure the dimensions of these cavities due to mineral infilling. This is a structure unique to advanced Mamenchisaurids, which differs from the procamerate internal structure seen in certain Neosauropods and the camerate condition found in Macronarians and Diplodocoids. 

Computed tomography scan of the anterior dorsal vertebra of Uragasaurus kalasinensis (holotype PRC 460). Three￾dimensional reconstructions of the vertebra in anterior view (a) and right lateral view (c). Corresponding computed tomography sections in anterior view (b) and right lateral view (d). The section plane corresponds to the dashed line separating the grey (anterior) and blue (posterior) regions in the 3D reconstructions. White boxes highlight camellate pneumatic cavities within the centrum. Red arrows indicate polygonal camellae within the camellate internal structure of the centrum. Black-and-white arrows indicate anatomical orientation in each panel. Nilpanpan et al. (2026).

Phylogenetic analysis of the taxonomic affinities of Uragasaurus kalasinensis consistently recovered the species as a basal Mamenchisaurid, although its precise placement within this group was hard to determine, which is unsurprising given the limited nature of the material. However, the same analysis consistently found Rhomaleopakhus turpanensis, a species formerly classified as being a member of the Mamenchisauridae, as being outside the group, which Nilpanpan et al. suggest may indicate the need to re-evaluate the taxonomic status of a number of Late Jurassic Asian Sauropods. 

A previous Mamenchisaurid specimen, KS26-4, was described from the Phu Dan Ma locality in 2013. This specimen comprises a nearly complete posterior cervical vertebra and two fragmentary ribs. Since this material did not contain any elements considered reliably diagnostic within the Mamenchisauridae, it was not formally described as a new species. This lack of diagnostic features, combined with a lack of shared elements with the material assigned to Uragasaurus kalasinensis leads Nilpanpan et al. to refrain from assessing whether it belongs to the same species.

Posterior cervical vertebra of Mamenchisaurus sp. from Phu Dan Ma, Kalasin Province,Thailand,Phu Kradung Formation, Late Jurassic–Early Cretaceous. Vertebra (SM KS26−4), right rib (SMKS26−2), and left rib (SMKS26−3) in anterior (A; A₂, close−up view of neural spine showing attachment scar for interspinal elastic ligament), left lateral (B), posterior (C), right lateral (D; D₂, close−up view of articular condyle showing a cancellous internal structure), and dorsal (E) views. Suteethorn et al. (2013).

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Spicomellus afer: A surprisingly well-armoured Ankylosaur from the Middle Jurassic of Morocco.

The Ankylosaurs were a group of heavily-armoured, short-limbed, wide-bodied, Ornithischian Dinosaurs, best known from Late Cretaceous deposits in Eurasia and North America. Although the group is known to have existed by the Middle Jurassic, remains from this period are limited to a jawbone and a few teeth from two sites in England, and it has been speculated that earlier members of the group may have lacked the heavy armour of the Late Cretaceous species. This is not unreasonable, the Late Cretaceous saw the emergence of a range of new predators, including novel groups of Theropod Dinosaurs and Crocodilians, and the first large predatory Mammals and Snakes, leading to the evolution of novel defence strategies in many herbivorous groups. 

Although well known from the Laurasian Continents, Ankylosaurs were for a long time thought to be absent from Gondwana. However, in 1986 this was changed by the discovery of Antarctopelta oliveroi, from the Late Cretaceous of Antarctica, the first known Dinosaur from that continent. This was followed in 1989 by the discovery of Kunbarrasaurus ieversi, a small Ankylosaur from the Early Cretaceous of Australia. The subsequent discovery of Stegouros elengassen from the Late Cretaceous of southern Chile and Patagopelta cristata from the Late Cretaceous of Argentina confirmed that Ankylosaurs were present, if uncommon, across Gondwana in the Cretaceous, and it was speculated that these Dinosaurs were members of a single clade, the Parankylosauria, which had split from its Laurasian cousins early in the history of the group, and developed a range of distinctive traits, including a distinctive tail weapon formed from five pairs of robust osteoderms, fused together to form a flat, fan-like weapon called a 'macuahuitl', in reference to a traditional weapon from Mesoamerica, made from a series of obsidian blades mounted on a wooden club, giving a sword-like appearance. 

Spicomellus afer was first described in 2021 from a single rib-fragment with fused spikes from Morocco. The fossil appeared to have clear Ankylosaurian affinities, and, importantly, came from the Middle Jurassic, apparently confirming the hypothesis of an early-branching clade of Ankylosaurs reaching Gondwana and diversifying there.

In a paper published in the journal Nature on 27 August 2025, Susannah Maidment of the Fossil Reptiles, Amphibians and Birds Section a the Natural History Museum, and the School of Geography, Earth and Environmental Sciences at the University of Birmingham, Driss Ouarhache, Kawtar Ech-charay, Ahmed Oussou, Khadija Boumir, and Abdessalam El Khanchou of the GERA Laboratory at Sidi Mohamed Ben Abdellah University, Alison Park of Emanya Fossil Preparation and Conservation, Luke Meade, also of the School of Geography, Earth and Environmental Sciences at the University of Birmingham, Cary Woodruff of the Phillip and Patricia Frost Museum of Science, and the Museum of the Rockies, Simon Wills and Mike Smith, also of the Fossil Reptiles, Amphibians and Birds Section a the Natural History Museum, Paul Barrett, again of the Fossil Reptiles, Amphibians and Birds Section a the Natural History Museum, and of the Evolutionary Studies Institute at the University of the Witwatersrand, and Richard Butler, once again of the School of Geography, Earth and Environmental Sciences at the University of Birmingham, describe a new partial skeleton of Spicomellus afer, enabling a more complete reconstruction of the species and a re-interpretation of the history of the Ankylosauria. 

The new material comprises a left quadrate, two cervical, two dorsal, four sacral and four free caudal vertebrae, two handle vertebrae, six dorsal ribs with spikes fused to their dorsal surfaces, both scapulocoracoids, ilia and pubes, the right ischium, two metatarsals, an elaborate cervical half ring bearing extremely long spikes, a sacral shield bearing small and large spikes, numerous plates, large and small spikes of various morphologies, and several compound osteoderms comprising combinations of small and large spikes. These suggest an unusually well-armoured Animal, even compared to other Ankylosaurs, casting doubt upon the prevailing idea that heavy armour developed in the group in the Late Cretaceous as a result of increased predation pressures. 

A life reconstruction of Spicomellus afer. (a), (b) A life reconstruction of Spicomellus afer  showing hypothetical positions of armour in dorsal (a) and right lateral (b)  views. (c) USMBA 19: a blade-like spine that is 43 cm long. (d) USMBA 70:  a compound osteoderm with large, oval base. The long spike is 35 cm long. (e) USMBA 12: part of the left ilium bearing a fused sacral shield, which includes  a large iliac spike lying dorsal to the acetabulum. The height of the spike, as  preserved, is 24 cm. (f) USMBA 14: cervical half-ring. The length of the longest spike is 87 cm. (g) USMBA 30: a slender, rounded spike that is 10 cm long. (h) USMBA 12: a portion of the left ilium bearing a fused sacral shield ornamented by small, rounded spikes. (i) USMBA 37: a slender, rounded spike that is 30 cm long. (j) USMBA 12: a large spike with a robust, expanded base plate. The spike is 23 cm long. The specimen was found in association with the iliac spike (e). (k) USMBA 26: a plate, probably from the pectoral region based on comparisons  with other Ankylosaurs. The plate is 24 cm in length. (l) USMBA 25: a compound osteoderm with spikes, one of which is broken. The better-preserved spike appears to have been the more slender of the two and is 34.5 cm long. (m) USMBA 17: a blade-like spine with an expanded base that is 27 cm long. (n) USMBA 63: a three-spiked osteoderm with a broken basal plate. The height of the middle spike is 3.5 cm. Matt Dempsey in Maidment et al. (2025).

The deposits from which the skeleton was recovered come from the Bathonian stage, making them between 168.2 and 165.3 million years old, making Spicomellus afer equal in age to the oldest known Ankylosaur fossils, a scattering of isolated from the Bathonian White Limestone of England, and close to the predicted split between the Ankylosauria and the Stegosauria. 

A phylogenetic analysis carried out by Maidment et al. was unable to recover the Parankylosauria as a distinct clade of Gondwanan Ankylosaurs. The Chilean Stegouros elengassen was found to be the sister species to all other Anylosaurs, apparently representing an early-diverging, and otherwise lost, lineage, while other members of the proposed Parankylosauria were scattered throughout the Ankylosauria as a whole, with their formerly apparent similarities being a result of convergent evolution.

A simplified time-calibrated strict reduced consensus tree showing  the putative phylogenetic position of Spicomellus afer. Note that the timescale for the  Middle Jurassic has been expanded so that branching patterns can be clearly  seen. Taxa in grey are from the Northern Hemisphere; those in black are from the  Southern Hemisphere. Green text denotes clades. Abbreviations: Aal, Aalenian; Alb, Albian; Apt, Aptian;  Baj, Bajocian; Barr, Barremian; Bath, Bathonian; Berr, Berriasian; Call, Callovian;  Cam, Campanian; Cen, Cenomanian; Con, Coniacian; Haut, Hauterivian;  Hett, Hettangian; Kimm, Kimmeridgian; Maas, Maastrichtian; Oxf, Oxfordian;  Plien, Pliensbachian; Sant, Santonian; Sine, Sinemurian; Tith, Tithonian;  Toar, Toarcian; Tur, Turonian; Vala, Valanginian. Maidment et al. (2025).

Based upon this, Maidment et al. conclude that heavy and extensive armour first appeared in Ankylosaurs in the Middle Jurassic, and was apparently a defining feature of the group from the outset. The further speculate that this may have been a result of sexual selection rather than predation pressure, something which could drive the rapid development of an anatomy distinct from that of their closest relatives. Under this scenario, the widespread appearance of heavily armoured Ankylosaurs in the Late Cretaceous might represent not the adaptation of a less well armoured group to a high predation environment, but rather the advantageous pre-adaptation of the group to such an environment, enabling the Ankylosaurs to flourish at the expense of less well-armoured rival groups.

Armour of Spicomellus afer. Richard Butler, Kawtar Ech-charay, Ahmed Oussou and Alison Park for scale (and the scale bar on the table is 8 cm long). Maidment et al. (2025).

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Jinchuanloong niedu: A new species of Eusauropod Dinosaur from the Middle Jurassic of Gansu Province, China.

Sauropod Dinosaurs first appeared around the begining of the Jurassic, undergoing an extinction event at the end of the Early Jurassic, which has been linked to a period of intense global warming, which only a single lineage, the Eusauropods, survived. All subsequent Sauropod groups diversified from this single lineage. One group of Eusauropods, the Neosauropods, would eventually radiate and become the dominant Sauropods through the Late Jurassic and Cretaceous, but in the Middle Jurassic a variety of non-Neosauropod Eusauropods could still be found, particularly in East Asia.

In a paper published in the journal Scientific Reports on 23 May 2025, Ning Li of the School of Earth Sciences and Resources at the China University of Geosciences, Xiaoqin Zhang of Chuxiong Normal University, Xinxin Ren of the Key Laboratory of Stratigraphy and Paleontology of the Ministry of Natural Resources at the Institute of Geology of the Chinese Academy of Geological Sciences, Daqing Li of the Institute of Vertebrate Paleontology at the Gansu Agricultural University, and Hailu You of the Key Laboratory of Vertebrate Evolution and Human Origins at the Institute of Vertebrate Paleontology and Paleoanthropology of the Chinese Academy of Sciences, and the College of Earth and Planetary Sciences at the University of the Chinese Academy of Sciences, describe a new species of non-Neosauropod Eusauropod from the Middle Jurassic Xinhe Formation of Gansu Province, China.

The Xinhe Formation is a 120 m thick sequence exposed in the Jinchuan District of Jinchang City, which starts at its bottom with a succession of conglomerates, sandstones, and siltstones, becoming finer further up where it becomes a sequence of interbedded shales and mudstones. It is thought to have been laid down in an ancient lake environment, roughly 166-165 million years ago. the specimen from which the new species is described was found in the lower part of this formation.

The new species is named Jinchuanloong niedu, where 'Jinchuanloong' means 'Jinchuan-dragon', and 'niedu' means 'Nickel-city', in reference to the abundant nickel resources in Jinchang, where the metal is mined extensively. It is described from a single specimen, comprising an almost intact skull, lateromedially compressed on its left side, along with the five anteriormost cervical (neck) vertebrae, and, separately, a section of twenty nine articulated caudal (tail) vertebrae. These were confirmed to be from the same animal by impressions of the pelvic girdle and sacral vertebrae, which connect them to the cervical vertebrae. These caudal vertebrae have not been excavated, but remain in place with a protective fence around them.

Skull of Jinchuanloong niedu (JCMF0132) in left lateral view. Abbreviations: a, aperture; an, angular; aof, antorbital fenestra; d, dentary; en, external naris; f, frontal; fo, foramen; inf, infratemporal fenestra;j, jugal; l, lacrimal; m, maxilla; n,nasal; o, orbit; p, parietal; pf, prefrontal; pm, premaxilla; po, postorbital; pop, paraoccipital process; q, quadrate; qj, quadratojugal; sa, surangular; snf, subnarial foramen; sq, squamosal. Li et al. (2025).

A phylogenetic analysis recovered Jinchuanloong niedu as a non-Neosauropod Eusauropod outside the two major non-Neosauropod Eusauropod clades, the Mamenchisauridae and the Tauriasauria, forming a sister taxon to the Tauriasauria plus the Neosauropoda. Li et al. suggest that the status of Jinchuanloong niedu as an apparently separate lineage outside of any of the major clades lends support to the idea that East Asia was a significant centre for Sauropod diversification in the Middle Jurassic.

Phylogenetic relationships of Jinchuanloong niedu. Li et al. (2025).

Li et al. further note that the dentition of Middle Jurassic Sauropods from East Asia, and in particular taxa from western China, is extremely variable, which they take as a sign of niche partitioning (i.e. different species having different diets), which in turn could have driven a high rate of taxonomic diversification.

Caudal vertebrae of Jinchuanloong niedu (JCMF0132). Li et al. (2025).

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Apolithabatis seioma: A new species of stem-group Ray from the Late Jurassic Solnhofen Limestone.

Chondrichthyans, or Cartilaginous Fish, are among the most numerous Vertebrate fossils in the geological record, but almost all these fossils are of isolated teeth. Whole-body fossils of Chondrichthyans, in contrast are extremely rare, limiting our understanding of the morphology and biology of ancient members of this group. 

The oldest known body fossils of Batomorphs, or Rays, date back to the Jurassic Period, considered to be an important interval in Shark and Ray evolution, and come from a series of  'Konservat-Lagerstätten',  the most notable of which is the Solnhofen Limestone, of southern Germany, which records a series of deposits laid down in the Kimmeridgian-Tithonian (i.e. between 154.8 and 143.1 million years ago) in a series of islands, known as the Solnhofen Archipelago, on the edge of the Tethys Sea with many enclosed, placid, lagoons that had limited access to the open sea and where salinity rose high enough that the resulting brine could not support life. The Solnhofen Limestone records a range of Vertebrate fossils in exquisite detail, including Holocephalians (Chimeras), Hybodont Sharks, Selachimorph Sharks, and at least two genera of Batomorphs.

Until fairly recently, all Batomorphs from the Solnhofen Limestone were refered to the genera Asterodermus and Spathobatis, but recent studies have suggested that none of the Solnhoffen specimens can be assigned to Spathobatis, a genus originally described from French specimens, with the German specimens assigned to Spathobatis reassigned to a new genus, Aellopobatis. All known specimens of Asterodermus and Aellopobatis from the Solnhoffen Limestone are thought to be of Tithonian age, although many specimens were collected decades ago from working quarries, and may not be dated accurately.

In a paper published in the journal PLoS One on 23 January 2025, Julia Türtscher and Patrick Jambura of the Department of Palaeontology and the Vienna Doctoral School of Ecology and Evolution at the University of Vienna, Frederik Spindler of PALAEONAVIX, and Jürgen Kriwet, also of the Department of Palaeontology and the Vienna Doctoral School of Ecology and Evolution at the University of Vienna, deescribe a new species of Batomorph from the Kimmeridgian Painten site within the Franconian Alb of central Bavaria.

Geographical setting and stratigraphy of Painten. (A) Geographical map of the ’Solnhofen Archipelago’ and Nusplingen. (B) Stratigraphic section of the Upper Jurassic (upper Kimmeridgian to lower Tithonian) sediments of the ’Solnhofen Archipelago’ (southern Germany), the sequence exposed at Painten is indicated by a bracket. Note that the new Batomorph fossil is from the Ulmense rebouletianum-horizon within the Lithacoceras ulmense Subzone of the Kimmeridgian (highlighted). Türtscher et al. (2025).

The new species is described from a single specimen, DMA-JP-2010/007, and is named Apolithabatis seioma, where 'Apolithabatis' means 'Fossil Ray' in Greek, while 'seioma' derives from the Greek 'seismós', meaning 'shake', in reference to the way in which the fossil was extracted from the rock. The single known specimen of Apolithabatis seioma is at least 120 cm in length, with a heart-shaped disc and a long narrow tail. It has two dorsal fins, both behind the pectoral girdle (i.e. on the tail).

Overview of DMA-JP-2010/007, the holotype of Apolithabatis seioma. (A) Photograph of the specimen. (B) Illustration of the specimen showing the skeletal morphology. Abbreviations: ac, antorbital cartilage; bp, basipterygium; br, branchial arches; c, vertebral centra; cf, caudal fin; d1, first dorsal fin; d2, second dorsal fin; hs, haemal spine; mk, Meckel’s cartilage, ms, mesopterygium; mt, metapterygium; nc, nasal capsule; ns, neural spine; pb, puboischiadic bar; pp, propterygium; pq, palatoquadrate; r, ribs; ra, pectoral fin radials; rap, pelvic fin radials; ro, rostrum; sc, scapulocoracoid; syn, synarcual. The scale bar equals 10 cm. Türtscher et al. (2025).

Previous phylogenetic studies have recovered Jurassic Batomorphs as a part of the crown group (i.e. descended from the last common ancestor of all living members of the group), with the Torpediniformes (Electric Rays) forming the sister group to all other members of the group. However, Türtscher et al. recovered Apolithabatis seiomai, along with the other Jurassic genera Aellopobatis, Asterodermus, Belemnobatis, Kimmerobatis, and Spathobatis, in a distinct clade which has a sister group relationship to all extant Batomoph groups (including the Torpediniformes). Since this implies that this group is not descended from the last common ancestor of all living Batomorphs, Türtscher et al. regard this group, which they name the Order Apolithabatiformes, to stem group Batomorphs.

Majority-rule consensus tree with bootstrap and jackknife frequencies (jackknife values in parentheses). Daggers before taxon names indicate extinct taxa. Türtscher et al. (2025).

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Simoniteuthis michaelyi: A new species of Vampire Squid from the Early Jurassic of Luxembourg.

The modern Vampire Squid, Vampyroteuthis infernalis, is considered to be a relict species, having a mosaic of features associated with the Octobrachia (Octopus) and Decabrachia (Squid, Cuttlefish, and the extinct Belemnites). Notably, it has a well-developed gladius (mineralised internal support equivalent to the pen of Squid or the cuttlebone of Cuttlefish), and a rudimentary tenth pair of arms, both features of the Decabrachia, leading to the common name 'Vampire Squid', although molecular studies have placed this Cephalopod firmly within the Octobrachia. Vampyroteuthis infernalis is therefore considered to be the sole living member of the Order Vampyromorpha. This order has a fossil record dating back to the Mesozoic, and has been divided into two suborders, the Vampyromorphina, which contains the living Vampire Squid and a single Oligocene species, Necroteuthis hungarica, and the Loligosepiina, which contains 13-14 genera from the Jurassic and Early Cretaceous.

In a paper published in the Swiss Journal of Palaeontology on 14 February 2024, Dirk Fuchs of the Bayerische Staatssammlung Für Paläontologie Und Geologie, and Robert Weis and Ben Thuy of the Musée National d’histoire Naturelle Luxembourg, describe a new species of Vampyromorph Cephalopod from the Early Jurassic Schistes Carton of Luxembourg.

The new species is described on the basis of a single specimen from a bituminous black shale exposed in Bascharage, southeast Luxembourg, which is considered to be of equivalent age to the better known Posidonia Shale of southwest Germany. These deposits are thought to have been laid down in a shallow part of the northwestern peri-Tethys, close to the London-Brabant landmass. The shales lack any sign of bioturbation or benthic fauna, have a high organic carbon content, and contain fossils of pelagic Animals with articulated skeletons and soft tissue preservation, leading palaeontologists to interpret the environment as being a shallow, enclosed sea with sheltered conditions and an oxygen-depleted seafloor.

The new species is named Simoniteuthis michaelyi, where 'Simoniteuthis' Jo Simon, a volunteer palaeontologist at the Musée National d’histoire Naturelle Luxembourg, who skilfully and patiently cleaned the fossil in the nodule and unveiled the soft part preservation (the sufix '-teuthis' means 'Squid'), and 'michaelyi' honours Patrick Michaely, the director of the museum.

The specimen is preserved as part and counterpart on a split shale slab, and consists of the gladius and head-arm complex, including the proximal and middle parts of the arms, and the eyeballs. The remains of two small Fish can be observed within the tentacle area. Seen under UV light, the musculature of the arms can be observed. Like other members of the Suborder Loligosepiina, Simoniteuthis michaelyi has only eight pairs of arms, lacking the rudimentary tenth pair found in the living Vampyroteuthis infernalis. Details of the gladius are largely obscured by leaked ink, but it is  23 cm in length, and has distinct lateral wings, a diagnostic feature of Vampyromorphs.

Simoniteuthis michaelyi, holotype (MNHNL TI024), Lower Toarcian, Serpentinum Chronozone, Exaratum Subchronozone, Bascharage. (A)–(D) slab; (E)–(G) counter-slab. (A) overview; (B) camera lucida drawing of (A); (C) close-up of the head–arm complex; (D) same under UV-light showing the weakly illuminating arm musculature; (E) overview; (F) close-up of the preyed Fish, red colour Specimen 1 (op, opercle; sop, subopercle), blue colour Specimen 2 (caud, caudal fin; sop, subopercle; centra, central vertebra); (G) same under UV-light. Scale bars are 10 mm. Fuchs et al. (2024).

The number of arms in Vampire Squid remains somewhat of a puzzle. The common ancestor of all Coleoid Cephalopods is thought to have had five pairs of arms, a state retained in the living Squid and Cuttlefish. Members of the Octobrachia, including Octopus and the Mesozoic Loligosepiina, appear to have lost one pair of arms, leaving them with four. The living Vampire Squid, however, retains a rudimentary fifth pair of retractable, filamentous arms. Since it is unlikely that the species would have re-evolved a fifth pair of arms, it is assumed that it is a member of a lineage that has never lost the fifth pair of arms, implying that the Octopus and Loligosepiina lineages lost their fifth pair of arms separately. Confusingly, the extinct Suborder Prototeuthina, variously thought to be the ancestor of all Octobrachians, the ancestor of Vampyromorphs but not Octopus, or Octopus but not Vampyromorphs, also appear to have had only four pairs of arms. Possible filamentous arms have been reported on two Jurassic Vampyromorphs; a specimen of Mastigophora brevipinnis from Wiltshire, England (though other members of the same species appear to lack these extra arms), and possibly a specimen of Jeletzkyteuthis coriaceus from the Posidonia Shale. Niether of these species are thought to be closely related to the Vampyromorphina, nor to one-another, which, combined with the uncertainty as to whether they have a tenth pair of arms at all, provides palaeontologists with little help in unravelling the history of the fifth pair of tentacles.

Gladius morphology of Simoniteuthis michaelyi, holotype (MNHNL TI024), Lower Toarcian, Serpentinum Chronozone, Exaratum Subchronozone, Bascharage. (A) Overview of the slab; (B) close-up of the anterior hyperbolar zone showing the course of growth increments; (C) schematic morphology and measurements; (D) overview of the counter-slab; (E) close-up of the posterior gladius showing the course of growth increments. Scale bars are 10 mm. Fuchs et al. (2024).

The presence of two small Fish associated with the head-arm complex of Simoniteuthis michaelyi has implications for the taphonomy of the Schistes Carton. The most logical explanation for Fish being found in this location is predation by the Mollusc, and such small Fish are known to have been an important part of the diet of many Early Jurassic Cephalopods. Cephalopods with captured prey Fish have been found in several other deposits where the bottom waters are thought to have been anoxic, which has led to the suggestion that they may have been distracted by the capture of the Fish, causing them to drift into anoxic waters and die.

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