Were Octopuses the largest predators in the Cretaceous seas?

Vertebrates became the top predators in almost all marine ecosystems shortly after the evolution of jaws, about 370 million years ago. This has allowed them to shape the structure of these ecosystems, as they have repeatedly evolved large body sizes, combined with increased strength, mobility, and cognitive abilities. In the Mesozoic Era marine predators such as Fish and Sharks were joined by Marine Reptiles such as Ichthyosaurs, Plesiosaurs, Mosasaurs, and Turtles, which secondarily returned to the seas from the land. In the Tertiary Mammalian predators such as Whales and Seals also followed this route. The evolution of the ability to crush shells and other hard parts (durophagy) among various Vertebrate groups caused a major reshaping of marine ecosystems during the Mesozoic (sometimes known as the 'Mesozoic Marine Revolution') in which many marine Invertebrates became smaller, more heavily shelled, and more cryptic in their habits, in response to this increased predation.

The only Invertebrate group which has apparently been occasionally able to challenge the vertebrates for this top-predator status are the Cephalopods (Octopuses, Cuttlefish, Squid, Nautiluses, and the extinct Ammonoids), free-swimming Molluscs which independently evolved jaws at about the same time as Vertebrates. Modern Octopuses are highly intelligent mid-level predators which have either lost their shells or retain them only as vestigial structures. This loss of a mineralised shell has enabled the Octopuses to become more mobile, develop better eyesight, and much greater intelligence.

The Mesozoic fossil record has produced a number of large Cephalopod jaws which have been interpreted as those of Octobranchians (Octopuses or Vampire Squid) likely to have exceeded 2 m in total length. The owners of these jaws have been assumed to have been 'high-level' predators, but little has actually been determined about them, as there are no cases of soft tissue preservation nor stomach contents from which this could be determined. Furthermore, it is very hard to determine the diet of a Cephalopod from its jaw structure, as, while there is considerable variation in such structure across the group, it does not appear to be related to diet.

In a paper published in the journal Science on 23 April 2026, Shin Ikegami of the Department of Earth and Planetary Sciences at Hokkaido University, Jörg Mutterlose of the Department of Geosciences at Ruhr University Bochum, Kanta Sugiura, also of the Department of Earth and Planetary Sciences at Hokkaido University, Yusuke Takeda of the Spectroscopy and Imaging Division at the Japan Synchrotron Radiation Research Institute, Mehmet Oguz Derin of Morgenrot Inc., Aya Kubota of the Department of Geosciences at Osaka Metropolitan University, Kazuki Tainaka of the Brain Research Institute at Niigata University, Takahiro Harada, also of Morgenrot Inc., Harufumi Nishida of the Department of Biological Sciences at Chuo University, and Yasuhiro Iba, once again of the Department of Earth and Planetary Sciences at Hokkaido University, re-examine the status of large Cephalopod jaws from the Mesozoic.

Ikegami et al. examined wear on the jaws of fossil Cephalopods. All such jaws are made from stiffened chitin in life, and therefore are more prone to cracking and wear in more durophagous species, i.e. those which are using their beaks to crack the skeletons of their prey.

Octopus jaws. (A) The entire body of a finned octopus and the position of their upper and lower jaw. (B) Anatomy of feeding organs. (C) The upper jaw. (D) The lower jaw. Ikegami et al. (2026).

Ikegami et al. examined 15 sets of large Octobranchian jaws which had previously been described from Japan and Vancouver Island. They also discovered a series of 12 further such jaws by using a method which they describe as 'digital fossil mining', in which high resolution tomography combined with an artificial intelligence system was used to search for specimens within Cretaceous rocks from Japan. All 27 specimens came from outer-shelf environments lacking wave or current influence, so that transportation-related abrasion to the jaws is unlikely. 

Precise, automatic segmentation of an Octopus jaw fossil and its fine structures using zero-shot learning AI. Ikegami et al. (2026).

All of the preserved specimens are interpreted as having come from members of the Order Cirrata (Finned Octopuses). The excellent preservation of the specimens and the lack of any potential to have been caused during preparation in specimens which had not been freed from the matrix allowed identification of wear patterns caused by the feeding habits of the living Octopuses with some confidence. Pigmentation patterns within the jaws enabled the reconstruction of growth patterns, and the large dataset being used enabled a reassessment of the taxonomy of Cretaceous Cirratans.

Descriptive terms of the Coleoid lower jaw. (A) Inner and outer lamellae. (B) Terms for the individual parts of the lower jaw. (C) Terms for the specific morphological characteristics of the lower jaw. (D) Morphological terms for the area near the jaw edges. (E) Measurements of lengths. Ikegami et al. (2026).

Previous studies have led to the description of five species of Octobranchians from the Cretaceous, all on the basis of fossil jaws. Upon re-examination of this material, Ikegami et al. conclude that only two of these species are valid, Nanaimoteuthis jeletzkyi and Nanaimoteuthis haggarti. Both are assigned to the genus Nanaimoteuthis, which was formerly thought to be a Vampire Squid, i.e. a member of the Order Vampyromorpha, but which Ikegami et al. reassign to the Winged Octopuses, Suborder Cirrata. Modern Winged Octopuses come in two forms, long-bodied forms, which have broad jaw wings, and short-bodied forms, which have narrow wings on their jaws. Because both species of Nanaimoteuthis have broad wings on their jaws, they are interpreted as long-bodied Winged Octopuses. Taking all the specimens, including the newly discovered ones, into account, Nanaimoteuthis jeletzkyi first appeared in the earliest Cenomanian (about 100 million years ago) and disappeared in the late Campanian (about 72 million years ago), while Nanaimoteuthis haggarti first appeared during the Santonian (about 86 million years ago, and also disappeared in the late Campanian (about 72 million years ago).

Huge lower jaws of fossil Octopuses and of an extant Giant Squid. (A) and (B) The largest lower jaws of the Late Cretaceous Finned Octopus species Nanaimoteuthis jeletzkyi, (A) NMNS DS00042 3LmvTpM, and Nanaimoteuthis haggarti, (B) KMNH IvP 902001. Both specimens show extensive loss of jaw material caused by wear. (C) A lower jaw of the extant Giant Squid Architeuthis dux (NSMT-Mo 85956), a species having the largest jaw among modern Cephalopods. (A) is a digital fossil jaw visualized as a 3D model; (B) is an exceptionally well-preserved non-digital fossil jaw; and (C) is a modern jaw dissected from a carcass of about 10 m total body length. Solid lines indicate the extension of striation on the outer surface of the hood and broken lines show the estimated outline of the rostrum without wear. The hood and lateral walls lost by weathering, shown as shadowed areas, are reconstructed based on the holotype and specimen NMNS DS00182 Ru8pBBo. (A) and (C) are exhibited in a mirrored position. Scale bar is 20 mm. Ikegami et al. (2026).

In Cephalopods, there is a direct relationship between the growth of the jaws and that of the soft body, allowing reliable body-size calculations to be made from the jaws alone. Based upon this, the largest specimens of Nanaimoteuthis jeletzkyi are estimated to have had a mantle length of between 67 cm and 184 cm, with a total body-length (including tentacles) of 2.8-7.7 m, while the largest specimens of Nanaimoteuthis haggarti are estimated to have had a mantle length of between 158 cm and 443 cm, with a total body length of 6.6-18.6 m, making it potentially one of the largest predators in the seas of the Late Cretaceous.

Body size estimation of Late Cretaceous Octopuses. The graph shows an allometric relationship between the length of the jaw and mantle in long-bodied species of extant Finned Octopus. The name of the corresponding species is shown along each growth curve. The sizes of Nanaimoteuthis jeletzkyi and Nanaimoteuthis haggarti are based on their largest specimens and are indicated by black vertical lines. Reconstruction of these two species, the extant Giant Squid, and gigantic Vertebrate predators in the Late Cretaceous are shown with their maximum total length. Ikegami et al. (2026).

The largest specimens of both species have beaks blunted and worn by continuous wear, while in juveniles the beaks tend to be sharp. However, it was possible to reconstruct the unworn beak length from the striations and ornamentation of the jaw surface. Thus the largest specimen of Nanaimoteuthis jeletzkyi has lost about 5.7 mm from the tip of its rostrum, while the largest specimen of Nanaimoteuthis haggarti has lost about 10.6 mm. In both cases this represents about 10% of the total jaw length. In both species the right edge of the jaw is more worn than the left edge. Wear takes the form of chips, scratches, and polishing, with the largest chips exceeding 1 mm in both species. The outer surface of the rostrum is polished, removing the original striations, but show numerous scratches, with these reaching up to 5 mm in length, extending vertically or obliquely from the jaw edge. In Nanaimoteuthis jeletzkyi the inner surface of the oral cavity is more heavily worn than the outer surface, which is indicative of the chewing of food. In Nanaimoteuthis haggarti there are many transverse cracks on the rostrum, these again reaching up to 5 mm in length.

Wear on the lower jaw of a modern Giant Pacific Octopus, Enteroctopus dofleini, (NSMT-Mo 85957). (A) Dorsal view of the entire mouth. (B) to (D) Close-ups of the wear, the positions of which are indicated by boxes in (A). (B) Lateral view of the right jaw edge. (C) Anterior view around the rostrum. (D) Dorsal view of the rostrum. Enteroctopus dofleini is the largest modern octopus species. Scale bars are 10 mm for (A) and 1 mm for (B) to (D). Ikegami et al. (2026).

There are two living suborders of Octopuses, the Finned Octopuses, or Cirrata, which are generally found in deep ocean environments, and the Finless Octopuses, of Incirrata, which are found in coastal environments. The discovery of specimens of the Finned Octopus Nanaimoteuthis jeletzkyi in deposits from the earliest Cenomanian (about 100 million years ago) pushes back the fossil record of the Ciratta by about 15 million years, and of crown-group Octopuses by about 5 million years. The presence of these fossils in Japan and on Vancouver Island indicates that large Finned Octopuses were found in outer shelf environments on either side of the Pacific during the Late Cretaceous (at which time the Pacific was already the world's largest ocean).

Wear on the largest lower jaw of Nanaimoteuthis jeletzkyi. (A) and (B) The entire specimen in (A) dorsal view and (B) anterior view. The broken line in (A) shows the boundary where striations become lost. (C) to (H) Close-ups of wear, of which the positions are indicated by boxes in (A) and (B). (C) Lateral view of the right jaw edge with chips (arrows). (D) Dorsal view of the rounded rostral part with scratches (arrows). (E) Oblique view of the rostral part with chips (arrows). (F) Area showing striations, which extends vertically in this figure (arrows). (G) Polished area where striation is lost, with scratches (arrows). (H) Asymmetric loss of the jaw edges (arrows), indicated by a mirrored image in 50% transparency overlaid beneath the original image. All panels show the specimen NMNS DS00042 3LmvTpM. Scale bars are 10 mm for (A), (B), and (H), and 1 mm for (C) to (G). Ikegami et al. (2026).

The living Cirrata can be split into two morphological groups, long-bodied forms (families Cirroctopodidae, Cirroteuthidae, Grimpoteuthidae, and Stauroteuthidae), and short-bodied forms (Family Opisthoteuthidae). Ikegami et al.'s analysis strongly suggests that both species of Nanaimoteuthis are long-bodied forms, something which is in line with both evidence from previously reported fossils, with more than 50 genera of Mesozoic Octobranchians discovered, all of which are long-bodied forms, and molecular phylogenies, which suggest that the Incerrata arose from within the Cerrata, implying that long-bodied forms arose first and that short-bodied forms evolved from these.

Wear on the largest lower jaw of Nanaimoteuthis haggarti. (A) and (B) The entire specimen in (A) dorsal view and (B) anterior view. (C) to (K) Close-ups of the wear, of which the accurate positions are indicated by boxes in (A), (B), and (G). (C) and (G) Lateral view of the right jaw edge with chips, scratches, and cracks. (E) Dorsal view of the rounded rostral part with scratches and cracks. Schematic drawings of (C), (E), and (G) are shown in (D), (F), and (H), respectively. (I) Area showing striation, which extends vertically in this figure. (J) Polished area where striation is lost. (K) Asymmetric loss of the jaw edges (arrows), indicated by a mirrored image in 50% transparency overlaid beneath the original image. All panels show the specimen KMNH IvP 902001. The broken line in (A), (G), and (H) shows the boundary where striation becomes lost. Scale bars are 10 mm for (A), (B), (E) to (H), and (K), and 1 mm for (C), (D), (I), and (J). Ikegami et al. (2026).

Nanaimoteuthis haggarti is significantly larger than Nanaimoteuthis jeletzkyi and examination of pigment patterns in the jaws of specimens of both species suggests that it grew significantly faster. Since the first known fossils of Nanaimoteuthis haggarti appeared about 86 million years ago, while the first specimens of Nanaimoteuthis jeletzkyi appeared about 100 million years ago, this suggests that these ancient Cirratans went through an evolutionary change enabling the emergence of gigantic forms about 10 million years after they first appeared.

The growth rate of Nanaimoteuthis haggarti and Nanaimoteuthis jeletzkyi based on pigmentation patterns. (A) Schematic drawings for the ontogenetic changes from juvenile to adult jaws, based on modern Octopuses. Unpigmented regions decrease with growth. (B) Nanaimoteuthis haggarti  (NMNS_DS00182_Ru8pBBo.stl), corresponding to the left stage of (A). (C) Nanaimoteuthis jeletzkyi (NMNS_DS00173_P74Doy1.stl), corresponding to the middle stage of (A). The broken lines in (B) and (C) indicate the original outline including unpigmented parts, reconstructed based on the adults of the same species. The posterior and ventral margins of (B) and (C) taper without fractures, indicating that they retain the original pigmentation patterns. The specimen of Nanaimoteuthis haggarti has a weakly pigmented inner lamella compared to that of Nanaimoteuthis jeletzkyi  with a smaller size. This pattern indicates that Nanaimoteuthis haggarti is in an earlier growth stage compared to Nanaimoteuthis jeletzkyi. Therefore, Nanaimoteuthis haggarti grew faster than Nanaimoteuthis jeletzkyi. Scale bars are 1 mm. Ikegami et al. (2026).

The extremely large size of Nanaimoteuthis haggarti makes it larger than the Giant Squid, Architeuthis dux, which has a maximum jaw length of about 80 mm, by about 50%. The Giant Squid can have a mantle length of about 2.5 m and a total length of about 12 m, something which has made it the largest known living or fossil invertebrate until now. It also rivals or exceeds the dimensions of the largest Vertebrates in the Cretaceous Seas, including the Ray-finned Fish, Xiphactinus audax, which reached about 5 m in length, the Lamniform Shark, Ptychodus mortoni, which reached about 10 m, Plesiosaurs of the genus Styxosaurus, which reached about 12 m, and the giant Mosasaur, Mosasaurus hoffmannii, the longest specimens of which may have reached about 17 m. Thus Nanaimoteuthis haggarti appears to have been one of the largest organisms in the Cretaceous oceans.

Most living Cephalopods are generalist carnivores, preying on Crustaceans, shelled Molluscs, other Cephalopods, and Bony Fish. Wear to the tip and edges of the beak is typically present in durophagous forms such as Octopuses and Cuttlefish, but absent in non-durophagous forms such as Squid. Thus the presence of such wear can be used to make judgements about the diet of fossil Cephalopods, such as Nanaimoteuthis jeletzkyi and Nanaimoteuthis haggarti. In these Cretaceous Cirratans it is estimated that about 10% of the jaws of large adult specimens had been worn away, but such wear is absent in juvenile specimens, as it is in contemporaneous Squid. The extent of wear seen is greater than is found in any living Cephalopod, suggesting that these were active carnivores, frequently using their beaks to crush hard shells and bone. The distribution of the wear on the jaws is asymmetric, which suggests lateralized behaviour (i.e. these Octopuses had a preferred side when manipulating prey, similar to handedness in Humans), something which is associated with cognative ability in Cepahlopods, suggesting that these Cretaceous Octopuses were already highly intelligent. 

The jaws of Nanaimoteuthis jeletzkyi and Nanaimoteuthis haggarti are much shorter than the jaws of most Late Cretaceous predatory marine Vertebrates. However, the long lateral walls of these jaws suggest they had powerful jaw muscles, and the cracks and chips on the beaks suggests that they were exerting forces which exceeded the resistance of the strongest parts of the jaw. In the larger Nanaimoteuthis haggarti transverse cracking is also present, probably representing larger shear failures caused by greater forces being applied. Thus these jaws appear to have been used to break up food items of considerable size and resilience. The difference in overall size is likely to have derived from the way in which Octopuses hunt, using their elongated arms to capture and overwhelm prey, rather than their jaws as in most marine Vertebrates.

Vertebrates have been the top predators in the oceans for most of the past 370 million years. The appearance of durophagous predation in a variety of lineages in the Mesozoic enabled a greater diversity of such predators, and drove marine ecosystems towards the structure we have today. Mesozoic Invertebrates have chiefly been viewed as prey during this process, adapting to increased predation pressures by becoming smaller, more heavily armoured, and more cryptic in their habits (better at hiding). Ikegami et al.'s study suggests that some Octopuses did not follow this path, instead becoming giant predators which rose to the top of the food web.

Convergent evolution among marine top predators in the Palaeozoic–Mesozoic. This model shows the acquisition of jaws and the reduction of superficial skeletons in the evolutionary history of marine Vertebrates (top) and Cephalopods (bottom) to become top predators. The grey horizontal bars show the chronological range of some selected groups of Vertebrates and Cephalopods. For Cephalopods, stepwise reductions of skeletons are indicated by the blue background. Ikegami et al. (2026).

Both Vertebrates and Cephalopods first evolved jaws in the Late Silurian or Early Devonian, between 423 and 407 million years ago, something which greatly improved their hunting efficiency. Vertebrates subsequently lost their external bony plates, and in larger species greatly reduced their scaly coverings to achieve smooth skin, while at the same time Cephalopods first internalised and then gradually lost their shells. In both cases, this was associated with increased swimming speeds, size, and intelligence. Vertebrates became top predators in the oceans long before Cephalopods completed this process, but during the Cretaceous some Octopuses were able to evolve a bodyplan which enabled them to compete with the very largest Vertebrates.

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Zosterophyllum baoyangense: A new species of Zosterophyllopsid Plant from the Early Devonian of Guizhou Province, China.

The first Vascular Plants appeared and underwent a dramatic radiation similar to that seem in Animals in the Cambrian, during the Late Silurian and Early Devonian. During this time both vegetative and sexual reproduction appeared, with some of the earliest Plants able to cover large areas through clonal growth, while at the same time producing spores which enabled them to distribute to new areas. During the Early Devonian structures such as leaves, roots, megaspores and secondary xylem also appeared. The Zosterophyllopsids formed a characteristic part of many Early Devonian floras, with species reported from China, North America, Europe and Australia. These Plants lacked leaves, and had a characteristic 'K'; or 'H' branching pattern, combined with lateral spike sporangia.

In a paper published in the journal Proceedings of the Royal Society B on 15 January 2025, Pu Huang of the Nanjing Institute of Geology and Palaeontology, Jia-Shu Wang of the Geological Museum of China and the Key Laboratory of Orogenic Belts and Crustal Evolution at Peking University, Yi-Ling Wang, also of the Key Laboratory of Orogenic Belts and Crustal Evolution at Peking University, Lu Liu of the National Natural History Museum of China, Jing-Yu Zhao of the School of Resources and Civil Engineering at Suzhou University, and Jin-Zhuang Xue also of the Key Laboratory of Orogenic Belts and Crustal Evolution at Peking University, describe a new species of Zosterophyllopsid Plant from the Early Devonian of Guizhou Province, China.

The new species is described upon the basis of two compression fossils from the Plant-bearing beds from the lower part of the Early Devonian Mangshan Group at Baoyang in Duyun City in Guizhou Province. These beds have been determined to be Pragian in age (410.8-407.6 million years old) on the basis of fossils which are also found in the Posongchong Formation of Yunnan Province, which in turn has been dated on the basis of spore assemblages, Plants and stratigraphic correlation It is placed in the genus Zosterophyllum, and given the specific name baoyangense, meaning 'from Baoyang'.

Zosterophyllum baoyangense  (a), (b) PB203562, part and counterpart, showing a fertile axis with K-shaped branching and a terminal spike. Arrows highlight branching points. The parts indicated by arrows (c) and (d) are enlarged in (c), (d), respectively; (c) K-shaped branching; (d) branching point showing a nearby protuberance (arrow); (e), (f) Enlarged view of the terminal spike in (a) and (b); (g) enlarged view of the basal part of the spike in (e). Arrow points to the margin of the basal sporangium. (h) Enlargement of the distal sporangia in (f) (arrow h), showing dehiscence line (white arrow) and peripheral rim along the convex distal margin (the area between two black arrows). Scale bars: (a), (b) 10 mm; (c)–(f), 1 mm; (g), (h), 0.5 mm. Huang et al. (2025).

Zosterophyllum baoyangense comprises a rhizome system with K-shaped branching and upright sporangia-bearing spikes 5.8-10.8 mm high. Each of these spikes has 5-10 sporangia, arranged in a spiral pattern. The sporangia are oval to semicircular, 1.6−2.0 mm high and 0.9−1.4 mm wide, departing from axis at an acute angle by a short stalk.

The Zosterophyllopsids are a distinctive group of Plants found worldwide from the Late Silurian to the Late Devonian. There are currently 37 described genera in the group, although it is not completely certain they form a monophyletic group. The earliest members of the group appear in the Ludlow (427.4-423.0 million years ago), with the group reaching its maximum diversity during the Pragian, then declining during the Emsian (410.62-393.47 million years ago), and eventually disappearing during the Frasnian (382.7-372.2 million years ago.

Zosterophyllum baoyangense is notably smaller that other members of same genus, with a complete specimen measuring 45.4 mm in length and 0,5-1.3 mm in width, with a spike 10.8 mm high. For comparison, the contemporary Zosterophyllum confertum from western Germany can reach 5.1 mm in width with a preserved length of 440 mm. Silurian members of the genus were typically smaller, though they grew over time, while Emsian species, while rarer, show a wider range of sizes. 

All species of Zosterophyllum lack any form of spikes, leaves, or leafy structures. However, they are presumed to have been able to photosynthesize due to the presence of stomata. With such a simple bodyplan, the only way that these plants would have been able to increase their photosynthetic surface would have been to get larger, a trend observed from their origin in the Late Silurian and through the Early Devonian. 

Zosterophyllum baoyangense, however, does not comply with this trend, being much smaller than known contemporary species, and even most Silurian specimens. Huang et al. suggest that this may be a sign of a much shorter life-cycle than other species. This in turn could be an adaptation to an unstable environment, or one with very limited resources, showing that early Vascular Plants had begun to show adaptation to different environments by the Early Devonian. 

Artist’s restoration of part of the Early Devonian Mangshan Flora, with Plant communities of Zosterophyllum baoyangense at the front, and Teyoua antrorsa, Zosterophyllum australianum and an unnamed zosterophyllopsid to the back. Huang et al. (2025).

The history of Vascular Plants can be divided into five evolutionary floras, the Rhyniophytic Flora, dominated by Rhyniophytes and Cryptospore producers, the Eophytic Flora, dominated by Zosterophyllopsids, followed by the Palaeophytic Flora,  the Mesophytic Flora and the (modern0 Cainophytic Flora. The Plants of the Rhyniophytic Flora were typically very small, and it is thought that the (first) terrestrial habitats that they inhabited were probably very ephemeral. The Plants of the Eophytic Flora, while still very simple, are generally much larger, which has been interpreted as a sign of more stable environments developing. In South China, however, a strongly seasonal wet-dry climate is known to have developed in the Early Devonian, which may have made it harder for early Plants to stabilize environments, producing dwarfed species such as Zosterophyllum baoyangense, which could have completed their entire life-cycles in a shorter period of time.

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An Early Cretaceous Plesiosaur from Ellesmere Island, Canada.

The Plesiosaurs were a group of Marine Reptiles which appeared in the Triassic and persisted till the End of the Cretaceous. The group obtained a global distribution during the Jurassic, when the supercontinent of Pangea broke up and high global temperatures led to large areas of the world's continents being submerged. However, towards the end of this period the situation had changed, when falling sealevels led to many ocean basins becoming isolated, many groups of large Marine Reptiles becoming extinct, and faunal communities becoming provincialized in different ocean basins. Plesiosaurs are not thought to have been strongly affected by the End Jurassic Extinction Event, but their fossil record is poor during the Early Cretaceous, limiting our understanding of the group during this interval.

In a paper published in the journal Acta Palaeontologica Polonica on 2 December 2024, Lene Delsett of the Natural History Museum at the University of Oslo, adam Smith of Nottingham Natural History Museum, Stephen Ingrams of Llandudno, and Simon Schneider of the Cambridge Arctic Shelf Programme, describe a Plesiosaur from the Early Cretaceous Deer Bay Formation of Ellesmere Island in the Canadian Arctic.

The specimen was excavated in 1952 by the Danish geologist Johannes Christian Troelsen, however, while he mentioned it in a report of his expedition to the area, it was never formally described. It was sent to the University of Copenhagen, where it appears to have undergone some preparation work by a student working under the supervision of curator Eigil Nielsen, and possibly subsequent curator Niels Bonde. The remains were subsequently packed into a series of wooden crates, one of which was opened and examined by Adam Smith in 2005. This box were subsequently misplaced, possibly during the flooding which affected the museum in 2011, but was subsequently relocated by curators Bent Lindow and Arden Bashfortht, and its contents transferred to a draw s in the main fossil Vertebrate collection. Two further crates, labelled '“Reptile Creek, Troelsen’s office' were discovered in 2019, and found to contain several girdle elements of the Plesiosaur specimen. Another box was discovered in the collections of the Zoological Museum in 2020, containing what was labelled as part of a 'Scoresbysund Plesiosaur', but which clearly belong to the Elis Island specimen. Another box, labelled 'NHMD 189689' contained some fragmentary ribs which also appeared to belong to the Elis Island specimen, but in the absence of any documentation were not included in the study.

The surviving specimen comprises 22 non-consecutive vertebrae from the cervical, dorsal, and caudal regions, hundreds of rib fragments, partial girdle elements, all four propodials, and several distal limb elements. All these elements are worn, and the larger elements mostly fragmentary. Delsett et al. were able to assign the specimen to the Cryptoclidid genus Colymbosaurus, but, due to the fragmentary nature of the specimen and a limited amount of overlapping material with other specimens, were not able to determine whether it belonged to either of the two previously described species in the genus, or from a different, as yet undescribed species. 

Selected vertebrae of Plesiosaur Colymbosaurus sp. NHMD 189834 from Ellesmere Island, Nunavut, Canada, upper Berriasian–lower Valanginian. (A) Cervical vertebra (centrum C), in articular (A₁), dorsal (A₂), ventral (A₃), and lateral (A₄) views. (B), (C) Pectoral vertebrae. (B) Centrum E in articular view. (C) Centrum D, in articular (C₁) and lateral (C₂) views. (D) Sacral? rib. (E)–(G) Dorsal vertebrae. (E) Centrum H, in articular (E₁) and lateral (E₂) views. (F) Centrum M (dorsal?) in articular view. (G) Centrum I in articular view. (H), (I) Caudal vertebrae. (H) Centrum O in articular view. (I) Centrum P in articular (I₁) and lateral (I₂) views. The letters used in the element names are written on the individual elements. Delsett et al. (2024).

Previous known specimens of Colymbosaurus spp. have been described from Spitsbergen, southern England and western Russia, so the Elis Island specimen represents a significant range expansion for the genus. The genus was therefore present in two separate ocean basins, the Boreal Arctic and Boreal Atlantic, which were connected by two seaways, one running between Norway and Greenland beneath the modern North Atlantic, and one in present day western Russia.

Map with Cryptoclidid occurrences in the Northern hemisphere. (1) Ellesmere Island; (2) Spitsbergen; (3) Great Britain; (4), (5) Russia. Delsett et al. (2024).

The Boreal Ocean during the Late Jurassic and Early Creraceous has been considered to have been an ecologically depleted environment, with most of the described fossils being Bivalves, Ammonites, and Belemnites. However, Cryptoclidid Pleisiosaurs were large, predatory Animals, reliant on Fish for at least part of their protein intake, which implies that these must also have been present. Delsett et al. suggest that, few deposits from this interval are noted for their fossil content, at least part of the apparent absence of many Animal groups may be because most studies of these deposits have concentrated on their stratigraphy rather than their faunal diversity, and therefore useful index fossils, such as shelled Molluscs tend to have been described, whereas less stratigraphically useful fossils, such as Plesiosaurs or Fish, may have been overlooked.

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Florissantia sp.: A fossil flower from the Early Eocene of Rajasthan.

The Malvaceae first appeared in the Cretaceous in North America, and have achieved a global distribution today, most notably as a significant component of almost all tropical forests. The genus Florissantia shows a number of features associated with different extant subfamilies of the Malvaceae, and is known from the Middle Eocene till the Miocene of western North America, with specimens known from British Colombia, Colorado, Montana, Oregon, and Washington, as well as a single specimen being known from the Sikhote Alin mountains of the Russian Far East.

In a paper published in the journal Botany Letters on 21 October 2024, Ashif Ali and Mahasin Ali Khan of the Palaeobotany, Palynology, and Plant Evolution Laboratory at Sidho-Kanho-Birsha University, and Raman Patel and Rajendra Singh Rana of the Department of Geology at Rauthan Hemvati Nandan Bahuguna Garhwal University, describe a specimen of Florissantia from the Early Eocene Palana Formation of Rajasthan, India.

The specimen comes from the Laminate Maroon Shale Bed of the Palana Formation, which is exposed at the Gurha Open-cast Lignite Mine at Bikaner in northwest Rajasthan. It is preserved as part and counterpart on a piece of a piece of split- laminated shale, which has been further exposed by micro excavation of successive layers of the rock with fine needles under a dissection microscope. 

(a) Map of Rajasthan showing the location of the Gurha opencast lignite mine (red star) Bikaner Rajasthan, India; (b) view of the fossil locality. Ali et al. (2024).

The preserved fossil is a star-shaped flower about 13 mm in diameter (sgnificantly smaller than any other member of the genus), with a calyx made up of five fused and rounded sepals of roughly equal length; the petals are missing. Importantly, the sepals each show numerous prominent veins, the pattern of which is used by Ali et al. as a diagnostic tool to place the specimen in the genus Florissantia.

(a) Transversely impressed, radially symmetric, pentamerous fossil flower of Florissantia sp. (SKBU/PPL/R/F/01A, part); (b) magnified image of the specimen showing thick filaments (marked by red arrows) surrounding the compressed, carbonaceous central area; (c) enlarged view of a single calyx lobe showing prominent parallel (marked by blue arrows) and radiating reticulate (marked by white arrows) venation; (d) counterpart of fossil flower of Florissantia sp. (SKBU/PPL/R/F/01B); (e) central area of figured in higher magnification; (f) line drawing of (c) showing parallel (marked by blue arrows) and reticulate (marked by red arrows) venation, Scale bars are 2.5 mm for (a), (b), (d), and (e) and 500 μm for (c) and (f). Ali et al. (2024).

The Palana Formation of Rajasthan has been dated to between about 55 and 52 million years before the present on the basis of palynological data (fossil pollen). This Early Eocene date makes the Bikanar specimen the oldest representative of the genus Florissantia, which together with its unexpected location, potentially makes the specimen highly significant. 

Line drawings of the Bikanar specimen and earlier reported extinct fossil flower species: (a) Bikanar fossil flower of Florissantia sp.; (b )fossil flower of Florissantia ashwillii from the Oligocene of Oregon; (c) fossil flower of Chaneya membranosa from the Miocene of Poland; this appears similar to Florissantia spp, but has unequal sepals. Scale bars are 5 mm. Ali et al. (2024).

The Palana Formation was laid down on the shores of an ancient lake, which is consistent with other locations where members of the genus Florissantia have been found. Other members of the genus are known from lake-associated Floras in tropical, subtropical, and temperate environments, often with some volcanic input; although the presence of volcanic ashes helps to preserve fine structures such as flowers, so it is possible that this connection with volcanic input reflects preservation bias rather than an environmental preference of the living plants.

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