The thing about disagreements in science is that they aren't used as an excuse for persecution and schism, based on the notion that the side with the most power or the most followers wins as though truth can be determined by violence or opinion polls. In science, disagreements lead to discovery because in scientific debate the fact are, or should be, neutral, so they can referee the debate. The side with the evidence wins and the losers graciously accept that they were wrong.
This is the case of the long-standing disagreement in palaeontology over the mystery of giant bones which regularly turn up in deposits on Europe, which were first discovered in 1850 by the British naturalist Samuel Stutchbury, who reported finding a large cylindrical bone in Aust Cliff, near Bristol, UK. Similar fossils have also been found at sites around Europe, including Bonenburg in North Rhine-Westphalia, Germany and Provence, France. Stutchbury assumed they were from an extinct crocodile-like land animal, labyrinthodontia, but others disagreed. Other candidates were long-necked sauropods and an as yet unidentified, large dinosaur.
Not the mystery may have been solved by two palaeontologists working at the University of Bonn, Germany. They have published their findings, open access, in the journal PeerJ and explain it in a Rheinische Friedrich-Wilhelms Universität Bonn news release:
Do some mysterious bones belong to gigantic ichthyosaurs?
A study carried out at the University of Bonn sheds light on a mystery that has puzzled paleontologists for 150 years
Several similar large, fossilized bone fragments have been discovered in various regions across Western and Central Europe since the 19th century. The animal group to which they belonged is still the subject of much debate to this day. A study carried out at the University of Bonn could now settle this dispute once and for all: The microstructure of the fossils indicates that they come from the lower jaw of a gigantic ichthyosaur. These animals could reach 25 to 30 meters in length, a similar size to the modern blue whale. The results have now been published in the journal PeerJ.
In 1850, the British naturalist Samuel Stutchbury reported a mysterious find in a scientific journal: A large, cylindrical bone fragment had been discovered at Aust Cliff – a fossil deposit near to Bristol. Similar bone fragments have since been found in various different places around Europe, including Bonenburg in North Rhine-Westphalia and in the Provence region of France. More than 200 million years ago, these areas were submerged beneath a huge ocean that covered vast swathes of Western and Central Europe. Fossil remains from the animal world of that time – including marine and coastal dwellers – have been preserved in the sediment.
There is still some debate to this day about the animal group to which these large, fossilized bones belonged. Stutchbury assumed in his examination of the first finds that they came from a labyrinthodontia, an extinct crocodile-like land creature. However, this hypothesis was questioned by other researchers, who believed instead that the fossils came from long-necked dinosaurs (sauropods), stegosaurs or a still completely unknown group of dinosaurs.
Unusual tissue made of protein fibers
Marcello Perillo has been investigating this theory as part of his Master’s Thesis in the research group headed by Prof. Martin Sander in the Institute of Geosciences at the University of Bonn. As part of his work, he examined the microstructure of the fossilized bone tissue.
Perillo first took samples from the bones that have so far not been classified.Already by the beginning of the 20th century, some other researchers had theorized that the fossils could possibly be from a gigantic ichthyosaur. Bones of similar species generally have a similar structure. Osteohistology – the analysis of bone tissue – can thus be used to draw conclusions about the animal group from which the find originates.
Marcello Perillo, lead author
Institute of Geosciences
Rheinische Friedrich-Wilhelms Universität, Bonn, Germany.
He then used a special microscope to prove that the bone wall had a very unusual structure: It contained long strands of mineralized collagen, a protein fiber, which were interwoven in a characteristic way that had not yet been found in other bones.I compared specimens from South West England, France and Bonenburg. They all displayed a very specific combination of properties. This discovery indicated that they might come from the same animal group.
Marcello Perillo
Ichthyosaur bones with a similar structure
Interestingly, fossils from large ichthyosaurs from Canada also have a very similar bone wall structure.
It is likely that the fossils come from the lower jaw of a sea creature. By comparing the size of the fragments with the jaws of other species in this animal group, it is possible to deduce the length of the animals: They could possibly have reached a length of 25 to 30 meters, as proponents of the ichthyosaur theory had originally speculated in an earlier study. “However, this number is only an estimate and far from certain – until, that is, we find more complete fossil remains,” says Perillo. Nevertheless, they were certainly exceptionally large.However, this structure is not found in fossil samples from other animal groups that I have studied. Therefore, it seems highly probable that the fragments in question also belong to an ichthyosaur and that the findings refute the claim that the bones come from a land-living dinosaur.
Marcello Perillo
The first ichthyosaur lived in the ancient oceans in the early Triassic period around 250 million years ago. Species as big as whales existed early on but the largest creatures only appeared around 215 million years ago. Almost all species of ichthyosaur then died out at the end of the Triassic period more than 200 million years ago.
The unusual structure of their bone walls – which is similar to carbon fiber reinforced materials – probably kept the bone very stable while allowing for fast growth. “These huge jaws would have been exposed to strong shearing forces even when the animal was eating normally,” says Perillo. “It is possible that these animals also used their snouts to ram into their prey, similar to the orcas of today. However, this is still pure speculation at this time.”
The animal from which these fossilized bones originated was unclear for a long time. The new study now indicates that they come from ichthyosaurs.© Photo: Marcello Perillo/University of Bonn
Using a modified drill, the researchers were able to remove pieces of the bone without destroying the valuable fossils. The resulting thin cross-sections of bone make it possible to examine the microstructure.© Photo: Marcello Perillo/University of Bonn
It is likely that the bones come from the lower jaw of a gigantic ichthyosaur that lived more than 200 million years ago. This is what their characteristic microstructure indicates.© Photo: Marcello Perillo/University of Bonn
The animals could probably have reached 25 to 30 meters in length.© Photo: Marcello Perillo/University of Bonn
Technical and research background is given in their open access paper in PerJ:
AbstractAs well as being a nice illustration of how science settled disputes with evidence, not by violence or by counting up the number of supporters each side can garner, like religions do, it is also another casual refutation of basic creationist dogma, like almost all biology, archaeology, palaeontology and cosmology papers. Here we have a clear example of an advanced organism that had evolved on Earth 250 million years before creationism claims the Universe was created from nothing by magic.
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.
Introduction
The Late Triassic covers an extremely long-time span (approximately 36 Ma), encompassing two of the fundamental biological revolutions of interest to paleontology, i.e., part of the Mesozoic Marine Revolution and the End-Triassic Mass Extinction (Harper, 2006; Davies et al., 2017). The Late Triassic also saw the rise of many tetrapod clades in the sea and on land that were to dominate the rest of the Mesozoic (e.g., plesiosaurs and non-avian dinosaurs) or are still prominent today (e.g., mammals). Nonetheless, the complex of biotic interactions of this Mesozoic Epoch and its protagonists still needs to be fully understood (Benton, 2015; Kelley & Penson, 2015.1). Giant ichthyosaurs (length >12 m), prominent elements of the ecological communities of Triassic seas, are no exception due to the absence of satisfactory fossils to unravel their evolutionary history and the still obscure timing, dynamics, and causes of their extinction at the end of the Triassic Period (Lomax et al., 2018; Sander et al., 2021).
Bone segments and putative giant ichthyosaurs from Europe
Large, but fragmentary bone finds from the famous Aust Cliff Rhaetic bone beds of the Bristol area (southwestern UK) were already reported in the 19th century (Stutchbury, 1850). These include what appeared to be large limb bone shafts of reptilian affinity, leading to extensive discussions in the paleontological community (Stutchbury, 1850; Sanders, 1876; Huene, 1912; Storrs, 1993; Storrs, 1994; Benton & Spencer, 1995; Galton, 2005; Naish & Martill, 2008 ; Redelstorff, Sander & Galton, 2014; Lomax et al., 2018). The Aust Cliff bone bed is one of a group of similar UK and continental European bone bed-type deposits formed in the Rhaetian epicontinental sea that covered much of Western and Central Europe (Sander et al., 2016; Barth et al., 2018.1; Cross et al., 2018.2; Perillo & Heijne, 2023) (Fig. S1). These bone beds yield various tetrapod fossils of both terrestrial and marine origin, often showing fragmentary preservation (Storrs, 1993; Storrs, 1994). The proposed taxonomic affinities of the large to gigantic bone shafts, hereafter less suggestively called “bone segments”, include “labyrinthodonts” (Stutchbury, 1850), dinosaurs (Sanders, 1876; Reynolds, 1946; Storrs, 1993; Storrs, 1994; Benton & Spencer, 1995; Galton, 2005) and unidentified archosaurs (Redelstorff, Sander & Galton, 2014).
The dinosaurian origin of said bone segments (hereafter ‘Dinosaur Hypothesis’) has been supported for the last decades, with Galton (2005) discussing five of the bone segments in detail and concluding that they either must represent sauropodomorph or, more likely, stegosaur long bone shaft fragments (femur, ?tibia). An inconsistency with the long bone nature of the segments would seem to be their lack of a continuous cortex and periosteal surface around their periphery. Instead, as much as two thirds of the periphery of shaft cross sections appears to consist of cancellous bone (Galton, 2005, figs. 4–6). Galton (2005) had already noticed the lack of an outer bone surface in some areas. Whereas this feature could be primary, as in a jaw bone (representing a suture surface or a surface facing the Meckelian canal), it also could result from heavy abrasion, which characterizes all Aust Cliff and other bone bed material.
Galton’s (2005) conclusion as to the stegosaurian nature of the bone segments has since been questioned by multiple workers (Maidment et al., 2008.1; Naish & Martill, 2008; Sander, 2013; Redelstorff, Sander & Galton, 2014; Lomax et al., 2018) due to the lack of diagnostic morphological features and stratigraphic arguments. In particular, the largest known stegosaur already occurring in the Late Triassic would be inconsistent with the known ornithischian fossil record and result in long ghost lineages (Galton, 2005; Maidment et al., 2008.1; Naish & Martill, 2008). Sauropods, on the other hand, would appear to be a reasonable option.
A histological test of sauropod affinities of the Aust Cliff bone segments was then conducted by Redelstorff, Sander & Galton (2014). Sampling two of the Aust Cliff specimens (BRSMG-Cb-3869 and BRSMG-Cb-3870, see Table 1) (Redelstorff, Sander & Galton, 2014) found a peculiar and previously undescribed set of histological characters (a thin cortex of fibrolamellar bone with longitudinal primary osteons and secondary osteons forming within the primary ones), inconsistent with sauropod or other sauropodomorph affinities (Redelstorff, Sander & Galton, 2014). In their primary cortex, sauropodomorph long bones show a different and rather uniform histology: laminar and plexiform fibrolamellar bone and, in the case of sauropods, almost no growth marks until late in life (Sander & Klein, 2005.1; Klein & Sander, 2007; Klein & Sander, 2008.2; Sander et al., 2011).
Following the recent find of a very large elongate and partially curved bone segment (BRSMG-Cg-2488, 96 cm long, Fig. S3B) in the Rhaetian of Lilstock (Lomax et al., 2018), also in SW England, this segment and the Aust Cliff bone segments were identified as fragments of the surangular bone derived from giant ichthyosaur jaws by Lomax et al. (2018). This interpretation by Lomax et al. (2018) was based on a morphological comparison with somewhat older giant ichthyosaurs from North America, specifically the Carnian Shonisaurus popularis from Nevada (Camp, 1980) and the Norian Shastasaurus sikanniensis (Fig. S3A) from British Columbia, Canada (Nicholls & Manabe, 2004). We term this hypothesis of the affinity of the very large Aust Cliff bone segments the ‘Giant Ichthyosaur Hypothesis’.
Support for the Giant Ichthyosaur Hypothesis would seem to come from an earlier find, now lost (Fig. S3C). Huene (1912) described a 1.4 m long bone segment from Aust Cliff which he identified as the fragment of a right lower jaw of a giant ichthyosaur, including part of four elements (dentary, splenial, angular, surangular) (Fig. S3C). Huene (1912) noted that this fossil had been accessioned to the “Bristol Museum” since 1877, presumably referring to today’s Bristol City Museum and Art Gallery (BRSMG). However, Huene (1912) did not provide a specimen number, and since his 1912 study, the specimen has not been mentioned again, and it may well have been destroyed in WWII. According to Huene’s (1912) description and illustration, the specimen consists of four non-fitting parts, the penultimate of which had been sectioned transversely (Fig. S3C) at some earlier point in time before Huene’s study.
Curiously, among the putative dinosaur long bone material described by Galton (2005) from Aust Cliff, there also is a transversely sectioned specimen (BRSMG-Cb-3870, Fig. S2) of about the dimensions noted by Huene (1912) (Fig. S3C). Galton did not cite Huene, and there is a possibility that the two authors did study the same specimen. Arguing against the identity of the two specimens is the poor preservation of the Galton specimen (whereas Huene emphasized the good preservation of his material) and the fit with another segment (whereas Huene noted the lack of fits).
Finds similar to the Aust Cliff and Lilstock material have come from the epicontinental French Rhaetian localities of the Autun area (Fig. S1) and from southern France (Fischer et al., 2014.1; Lomax et al., 2018), as well as most recently, from the German locality of Bonenburg (Fig. S1) (Sander et al., 2016; Wintrich et al., 2017.1) and the Swiss Alps (Sander et al., 2022, fig. s5). Fischer et al. (2014.1) also had interpreted their material as ichthyosaurian but did not extend their considerations to the UK material and did not cite Huene (1912). Huene (1912), on the other hand, just described this one specimen from Aust Cliff and did not comment on the putative dinosaur leg bone shafts from the same locality nor on the French Rhaetian ichthyosaur material, all of which were known at the time.
The Late Triassic giant ichthyosaur record
Ever since the work of Charles S. Camp on Shonisaurus popularis from Berlin Ichthyosaur State Park in the Carnian Luning Formation of Nevada, USA, in the 1950s (Camp, 1980), it has been clear that Late Triassic ichthyosaurs reached body lengths of 15 m or more and must have been substantially larger than post-Triassic ichthyosaurs. The S. popularis material has been reevaluated several times since with regard to its size, skeletal reconstruction, taphonomy, and reproductive biology (Kosch, 1990; Hogler, 1992; McGowan & Motani, 1999; Kelley et al., 2022.1). Even larger and more complete than any of the S. popularis finds is the holotype skeleton of Shastasaurus sikanniensis (Nicholls & Manabe, 2004) from the middle Norian of British Columbia, Canada. Based on field data, this individual is estimated to have been 21 m long (Nicholls & Manabe, 2004).
It is also now acknowledged that various other ichthyosaur finds from the Late Triassic must represent animals over 10 meter in length, but most giant ichthyosaurs are represented by woefully incomplete, disarticulated, and fragmentary material from around the world (Callaway & Massare, 1989; McGowan & Motani, 1999; Sander et al., 2022; Kelley et al., 2022.1) which hinders the anatomical descriptive effort. In continental Europe, the fragmentary, often reworked, and poorly understood finds attributed to giant ichthyosaurs come from late Norian to Rhaetian outcrops of France (Fischer et al., 2014.1), the eastern Swiss Alps (Sander et al., 2022), and from a recently discovered Aust Cliff-type bone bed near the central German village of Bonenburg (Fig. S1) (Sander et al., 2016; Wintrich et al., 2017.1). Unlike all the other Rhaetian localities with putative giant ichthyosaurs, the Bonenburg deposit is precisely dated palynologically, ranging from late middle to early late Rhaetian in age (Schobben et al., 2019; Gravendyck et al., 2020). The Bonenburg ichthyosaur fossils include large but very short vertebral centra, a very large neural arch, and very large rib fragments (Sander et al., 2016)). In addition, the bone bed frequently yields heavily abraded fragments of thick cortical bone up to 25 cm in length (Figs. S4A, S6A), which we hypothesize to be fragments of bone segments similar to the more complete British and French specimens (Figs. S2A, S3B).
Understanding the affinity of the fragmentary Late Triassic ichthyosaurs and of the large, more obscure fragmentary finds, is important because of the absolute size of these remains, representing records of the largest animals inhabiting the Late Triassic oceans (Lomax et al., 2018; Sander et al., 2022). The fossils represent animals that far exceeded the size of any other marine tetrapods except for the largest species of baleen whales and archaeocetes (Bianucci et al., 2023.1). The importance of these fossils also relates to the patterns of extinction at the end of the Triassic, given that very large ichthyosaurs appear to have persisted to the late Rhaetian (indicated by the Bonenburg finds) but are lacking in the Jurassic.
The lack of clear and unequivocal external morphological features in the Rhaetian European bone segments due to their fragmentary and reworked nature makes alternative approaches such as microstructure analysis (microanatomy and osteohistology) critically important for investigating the possible affinities of these fossils. Both Galton (2005) and Lomax et al. (2018) illustrated cross sections of UK fossils and discussed microanatomy (but not histology, which is not accessible without thin-sectioning). Galton compared the midshaft microanatomy of BRSMG-Cb-3869, 3870, and 4063 from Aust Cliff to that of various dinosaurs and concluded that the fossils must represent stegosaurs based on the coarse cancellous bone structure of the medullary region. Lomax et al. (2018) noted and illustrated in detail the same coarse cancellous bone structure but did not use microanatomical arguments as evidence for determining affinity, only cross-sectional shape. Histological analysis was already performed on two Aust Cliff specimens (BRSMG-Cb-3869 and BRSMG-Cb-3870) by Redelstorff, Sander & Galton (2014) (Table 1), but without considering possible ichthyosaurian affinities of the fossils.
Here we undertake a detailed and comprehensive comparison and sampling of most European Rhaetian “bone segments” and putative giant ichthyosaur jaws for histological analysis. The main aim of this study thus is to histologically test the Giant Ichthyosaur Hypothesis by searching for shared histological characters among European material of confirmed or proposed ichthyosaurian nature, on one hand, and bonafide Late Triassic giant ichthyosaurs, such as S. sikanniensis, on the other. We also compare the “bone segments” histology with other terrestrial and aquatic tetrapods that are known to have reached very large body size in the Late Triassic such as sauropodomorph dinosaurs, rauisuchians, dicynodonts, and plesiosaurs.
Figure 1: Main histological features of the giant ichthyosaurs lower jaws.
(A) BRSMG-Cg-2488 R-101 seen in cross-polarized light (left) and with a lambda filter added (right). The specimen shows a regular arrangement of rows of primary osteons with secondary osteons within, separated by thin periosteal GM (white arrows), and a high number of osteocyte lacunae. (B) Polarized light view of BRSMG-Cg-2488 R-101 showing the grid pattern of periosteal intrinsic fibers that characterizes the intrinsic fiber matrix (IFM). (C) BRSMG-Cg-2488 R-101 in circular polarized light revealing the seemingly helicoidal arrangement of the periosteal structural fibers and their interconnection within osteonal lamellar bone (top left). (D) Normal light view of the cross section of PLV-1964 showing two primary osteons. The right one (dotted line) shows a secondary osteon within the primary one. (E) Longitudinal section of PLV-1964 showing strands of unmineralized fibers (dark) running longitudinally in a herringbone pattern (green arrows) in normal light (left) and in polarized light with lambda filter (right). (F) PLV-1964 in normal light showing the irregular shape of osteocyte lacunae and the unmineralized fibers (green arrows). Abbreviations: Lb, lamellar bone; Po, primary osteon, IFM, intrinsic fiber matrix; Rl, resorption line; Vc, vascular canal. Scale bars equal 100 µm (A, B, D, E), and 50 µm (C, F).
Figure 2: Overview of composite micrographs of selected thin sections.
The resorption front is indicated by a blue dashed line, a black dotted line indicates the boundary between rDC and tDC. (A) BRSMG-Cb-3869, from Aust Cliff; (B) BRSMG-Cb-3870, from Aust Cliff; (C) BRSMG-Cg- 2488, from Lilstock; (D) BRSMG-Cb-4063, from Aust Cliff; (E) PLV-1964, from Cuers; (F) detail of the outer cortex of BRSMG-Cg- 2488 showing secondary osteons (white stars). White dotted lines indicate the still visible borders of primary osteons, white arrowheads indicate the resorption lines of the secondary osteons. Abbreviations: DC, deep cortex; OC, outer cortex; rDC, regular deep cortex; RF, resorption front; So, secondary osteon; tb, trabecular bone; tDC, template deep cortex. Scale bars equal 2 mm (A–E), and 500 µm (F).
Figure 3: Features characterizing the areas identified as outer cortex, trabecular bone and deep cortex.
(A) Outer cortex of BRSMG-Cb-4063 in normal light (left) and in cross-polarized light with lambda filter added (right) showing primary tissue and growth marks (white arrows). Secondary osteons are present on the outer edge of the bone and may interrupt the continuity of the GM. The outer surface also shows diagenetic damage leading to the opening up of a secondary osteon. (B) BRSMG-Cb-3870 showing GM (white arrows) and a vascular canal open to the outer bone surface. (C) Longitudinal section of PLV-1964 in cross-polarized light (left) and with a lambda filter added (right) revealing longitudinal vascularization. (D) Detail of trabecular bone of PLV-1964 showing primary IFM and secondary lamellar bone in cross-polarized light. (E) BRSMG-Cg-2488 R-101 showing a template cortex characterized by parallel rows of primary and secondary osteons (white and purple narrow arrows) bordered by successive GM. Note the steep downturning of the rows in the vicinity of the nutrient canal. (F) Nutrient canal of BRSMG-Cb-3869 in normal light showing the presence of primary simple vascular canals and resorption cavities on the outer edge of the canal. Abbreviations: Lb, lamellar bone; NC, nutrient canal; oc, open vascular canal; IFM, intrinsic fiber matrix; so, secondary osteon. Scale bars equal 100 µm (A, C, D), 500 µm (B), and 2 mm (E, F).
Figure 4: Overview of WMNMP88133, the largest cortical bone fragment from the late Middle Rhaetian of Bonenburg, Germany.
(A) Cross section showing a dark diagenetic seam staining the outer bone surface and the resorption front (blue dotted line). Note the low curvature of the outer bone surface and the great thickness of the cortex, suggesting that the fragment derives from a very large bone. (B) Overview of the external cortex showing the characteristic, strictly longitudinal vascular canals arranged in circumferential rows, vascular canals open to the outer bone surface (partially hidden by the dark seam), secondary osteons inside primary ones, and concentric secondary osteons. The obliteration of the multiple parallel rows of GM (white arrows) reveals the border between rDC and tDC (white dotted line). (C) Detail of the tDC, showing secondary osteons and IFM (left half of image cross-crossed polarized light, right half circular polarized light). The intrinsic fibers form parallel GM of alternating colors (white arrows). (D) Secondary osteon filled in by lamellar bone followed by woven or poorly mineralized bone (left side cross-polarized light with lambda filter, right side cross-polarized light only). Pink arrowheads point at the numerous plump or irregularly shaped osteocyte lacunae in the IFM and in the innermost layer of the osteon. White arrowheads points to the less numerous flattened osteocyte lacunae (white arrows) in the lamellar bone. (E) Longitudinal section seen in cross-polarized light with a lambda filter showing unmineralized fiber strands (dark, green arrows). Abbreviations: Cl, cementing line; HT Haversian tissue; IFM, intrinsic fiber matrix; Lb, lamellar bone; oc: open vascular canal; rDC, regular deep cortex; RF, resorption front; tDC, templating deep cortex; So: secondary osteon; Vc, vascular canal; Wb, woven bone. Scale bars equal 2 cm (A), 1 mm (B), 100 µm (C–E).
Figure 5: Histology of the sample from the splenial of the Shastasaurus sikanniensis type specimen RTMP-1994-378-0002 from the middle Norian of British Columbia, Canada.
(A) Cross section of the splenial section (dorsal at top), the highly cancellous structure is evident, as well as the lack of a dense outer cortex, caused by taphonomic processes. (B) Close-up view of area indicated in (A). Primary cortex with IFM is preserved interstitially between secondary trabeculae. Left half of the image is in cross-polarized light, right half in normal light. Note the dark stain of the bone tissue in the normal-light image. Post-mortem, pre-burial erosion of the bone surface is indicated by the truncation of the bone structure and by the cover of opaque sediment. (C-D) Close-up showing IFM in cross-polarized light (C) and in circular polarized light (D). Note the helical arrangement of the fibers around a dark core. Abbreviations: IFM, intrinsic fiber matrix; RC, resorption cavity. Scale bars equal 5 mm (A), 100 µm (B), 50 µm (C, D).Perillo M, Sander PM. 2024.
The dinosaurs that weren’t: osteohistology supports giant ichthyosaur affinity of enigmatic large bone segments from the European Rhaetian. PeerJ 12:e17060 https://doi.org/10.7717/peerj.17060
Copyright: © 2022 The authors.
Published by PeerJ, Inc. Open access.
Reprinted under a Creative Commons Attribution 4.0 International license (CC BY 4.0)
I have included a lot of detail from this paper so creationists will have more to trawl through looking for something to lie about or misrepresent as a change from their usual blanket assertion that the scientists got the dates wrong or forged the fossils, or some such parrot squawk of a response to help them cope with the cognitive dissonance papers like these cause them.
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