Malformations in Trilobites from the Silurian and Devonian of Europe.

Malformations in fossils, such as pathologies caused by infections, scars left by recovered injuries, or teratologies caused by developmental problems, can tell us a lot about how extinct organisms grew and interacted with their environments, although when analysing these is clearly preferable to have access to non-malformed examples of the same species, or at least a close relative.

Trilobites were a diverse and abundant group of Arthropods which appeared early in the Cambrian, and survived until the End Permian Extinction. Their dorsal exoskeleton was heavily biomineralized, and was shed periodically to allow the animals to grow. This has lead to an extensive fossil record with Trilobites being extremely common in many Palaeozoic marine deposits. This abundant fossil record makes Trilobites an excellent candidate group for the study of malformations.

In a paper published in the journal Acta Palaeontologica Polonica on 22 April 2025, Russell Bicknell of the Division of Paleontology (Invertebrates) at the American Museum of Natural History, and the Palaeoscience Research Centre at the University of New England, Patrick Smith of the Palaeontology Department at the Australian Museum Research Institute, and the Department of Biological Sciences at Macquarie University, Lisa Amati of Paleontology at the New York State Museum, and Melanie Hopkins, also of the Division of Paleontology (Invertebrates) at the American Museum of Natural History, describe malformations in European Silurian and Devonian Trilobite specimens from the collections of the Natural History Museum in London and the New York State Museum.

The first specimen examined by Bicknell et al., NYSM 19739, is an isolated cephalon (head part) from a Harpetid Trilobite, Lioharpes venulosus, from the Early Devonian Koněprusy Limestone of the Czech Republic, in the collection of the New York State Museum. The cephalon is 26.2 mm long and 22.3 mm wide with a u-shaped indentation on its right marginal rim. This indentation is 5.6 mm long and extends 1.9 mm towards the midline. The marginal rim is covered in small circular pits, which around the indentation are irregular, ovate, and occasionally fused into larger pits.

Malformed Harpetid Trilobite Lioharpes venulosus, NYSM 19739 from the Koněprusy Limestone, Pragian, Lower Devonian, Koněprusy, Czech Republic. (A₁) complete cephalon; (A₂) close up showing U-shaped indentation (arrow). Specimen coated in ammonium chloride sublimate. Bicknell et al. (2025).

Bicknell et al. note that malformations to the cephalic fringes of Harpetid Trilobites have been recorded before, and that these are usealy attributed to injuries, an analysis with which they concur. However, they also observe that injuries can happen in a variety of ways, with fringe injuries having previously attributed to problems during moulting, failed predation attempts, or unknown causes. They suggest that a moulting injury is the most likely explanation for the injury to the Koněprusy specimen, with the delicate fringe likely torn during moulting, and the enlarged and fused pits being a result of fusion of the torn margin during healing. Various purposes have been suggested for the cephalic fringes of Harpetid Trilobites, including filtering for food, sensory roles, sediment ploughing, hydrostatic support, cephalic reinforcement, burrowing, and enhancing hydrodynamic efficiency. Whatever the purpose of this organ, an injury to it is likely to have been detrimental to the living Trilobite, and presumably repairing this injury would have been a priority during subsequent moults.

The second specimen, NHMUK PI In 65061, looked at is a Phacopid Trilobite, Calymene blumenbachii, from the Early Silurian Much Wenlock Limestone Formation of Shropshire, England, in the collection of the Natural History Museum. This specimen comprises a partial cephalon, thorax, and pygidium, with a total length of 92.9 mm and a width of 48.6 mm. The second thoracic axial ring (middle part of the second segment of the thorax) of this specimen is covered by a structure with closely spaced openings, which has an elevated round crater at its right extremity, with an opening 1.7 mm across.

Bicknell et al. interpret this as an encrusting Trepostome Bryozoan covering the 3rd thoracic tergite, with the larger opening being an ovate zoarium (specially modified zooid which produced eggs). The restriction of the encrustation to one tergite strongly suggests that this happened while the Trilobite was alive, and that the Bryozoan colony was therefore unable to overgrow the articulations between tergites.

Abnormal Calymenid Trilobites Calymene blumenbachii from the Much Wenlock Limestone Formation, Homerian, Wenlock, Silurian, England, UK. (A) NHMUK PI In 65061, (A₁) complete specimen; (A₂) close up showing the large bryozoan growth. (B) NHMUK PI In 19857 showing pygidial ribs that terminate early (white arrows) and are fused proximal to the medial lobe (black arrow).  Bicknell et al. (2025).

The next specimen examined, NHMUK PI In 19857, is another example of Calymene blumenbachii from the Much Wenlock Limestone. This specimen is a partial pygidium (tail part) 13.2 mm long and 18.2 mm wide. On the right side of this specimen the pygidial ribs are disrupted and irregular, with two ribs terminating 1.6 mm short of the pygidial margin, while another two fuse 1.2 mm from the pygidial axis.

Bicknel et al. observe that similar deformations to the pygidia have been observed in a wide range of other Trilobites, including Dalmanities pleuroptyx, Dechenella macrocephalus, Niobina sp., and Prionopeltis archiaci. They attribute these deformations to genetic or developmental issues, but suggest that the limited disruption to the pygidium they caused did not represent a major handicap.

Specimen NYSM 19740 is an Acastid Trilobite, Treveropyge sp., from the early Devonian Saint Céneré Formation of Mayenne in northwest France. this specimen is another isolated pygidium, s 11.6 mm long and 17.9 mm wide. It has a deformation to the axial lobe, which is asymmetric, with two of the axial rings malformed and curving to the right.

Malformed Acastid Trilobite Treveropyge sp., NYSM 19740 from the Saint Céneré Formation, Lochkovian, Lower Devonian, Mayenne, France. (A₁) Complete pygidium; (A₂) close up showing asymmetrical axial lobe and incomplete axial ring (arrows). Specimen coated in ammonium chloride sublimate. Bicknell et al. (2025).

Again, Bicknell et al. note that similar deformations have been seen in other Trilobites, such as Calliops marginatus, Dolicholeptus licticallis, and Sceptaspis lincolnensis. They suggest that these malformations are caused by genetic deformations, leading to incomplete development or non-functional somites.

The final specimen examined, NHMUK PI I 1108, is an external impression of a partial pygidium belonging to the Styginid Trilobite Scutellum (Scutellum) pardalios, from the Middle Devonin Barton Limestone Member of Devon, England. This impression is t is 59.5 mm long and 44.0 mm wide. On the right side of this impression (i.e. on the left side of the Trilobite) two ribs fuse into a single rib 29.1 mm from the pygidial axis. This single rib then terminates 4.8 mm from the pygidial margin.

Malformed Styginid Trilobite Scutellum (Scutellum) pardalios, NHMUK PI I 1108 from the Barton Limestone Member, Torquay Limestone Formation, Givetian, Middle Devonian, England, UK. (A₁) Pygidium preserved as external impression; (A₂) close up showing fused pygidial pleurae (arrows). Bicknell et al. (2025).

Bicknell et al. note that the surface of the pygidium was covered with ornamentation, with no visible break in this, which appears to  rule out the malformation having been formed by an unsuccessful predation attempt, or similar injury. Recovery from injury is the most commonly sited reason for malformations seen in Styginid Trilobites, followed by parasitic infections during early development, which seems equally unlikely. Bicknell et al. suggest instead that this deformity might be the result of a difficult moult, or possibly a genetic aberration. They do not believe this minor deformity would have significantly affected the living Trilobite.

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Direct archaeological evidence for the torture and mutilation of Mapuche prisoners during the sixteenth century 'War of Arauco'.

The conflict between the conquering Spanish and the indigenous peoples of the Americas has retained a reputation for particular brutality, even against the wider context of European conquests of non-European peoples. In Chile the conflict between the Spanish and the indigenous Mapuche people lasted for almost three centuries, from 1536 to 1810, a period known as the 'War of Arauco', although this is somewhat of a misnomer, with the 'war' comprising several periods of intense conflict, interspersed with periods of peace. The Mapuche people were able to resist conquest by the Spanish for so long due to their willingness to adopt the tools of their enemies, including firearms, cavalry, and military tactics.

In 1550 the Spanish commander Pedro de Valdivia reported execution and mutilating Mapuche prisoners by cutting off of hands, feet, noses, ears, and breasts, which was a common practice for Spanish leaders of the time (de Valdivia was defeated in battle, captures and executed by the Mapuche three years later). The tactics used by the Spanish in the Americas typically involved capturing political and religious leaders, forcing surrender through torture, and then publicly massacring important members of the community, usually in brutal ways.

Although well documented, little physical evidence for this conflict exists today, due to the humid climate and regular heavy rains of south-central Chile, which are not favourable for the preservation of archaeological remains. Furthermore, many archaeological collections made in the first half of the twentieth century have either been lost or kept so poorly that it is hard to assess their original context. 

In a paper published in the journal Open Archaeology on 19 July 2023, Juan Francisco Reyes Sánchez of the Equipo Chileno de Antropología Forense, and Alberto Enrique Pérez of the Facultad de Ciencias Sociales y Humanidades at the Universidad Autónoma de Chile, present a study of two burials at the Newen Antug archaeological site in Neuquén Province, Argentina, which show evidence of violence likely to have been linked to the conflict with the Spanish. 

The Newen Antug archaeological site lies on the Argentinian side of the Valdivia River Basin, which forms the border between Chile and Argentina, within the Lácar and Nonthué Lake System. The site was first occupied about 880 years ago, and has yielded, amongst other things, the earliest known canoe burial in South America. 

Newen Antug site, on the shores of Lácar Lake, which is part of a binational archaeological site in the Valdivia river basin. The inset shows the stash of Florentine stirrup location and small Spanish fort location. Reyes Sánchez & Pérez (2023).

It this study Reyes Sánchez and Pérez examine two individuals, one female and one male, which date from the second occupation of the site, Both were laid on their right sides with their legs flexed and their arms parallel to their bodies. Their heads (in both cases) have rotated paraventral on their axial axes as a result of the loss of thoracic volume and the resistance of the intervertebral tissues due to compaction of the grave. 

The grave of the female individual has an east-west axis with the body laid facing to the south. The male individual is laid in a grave with a northwest-southeast axis, facing to the northeast. Three clay pots were placed within the grave of the female, decorated in the local Valdivia Red on White Bichrome tradition, and arranged around her head.

Plan of the excavation of the mortuary features of Individuals 1♀ and 2♂ of the Newen Antug site. Reyes Sánchez & Pérez (2023).

The female individual is estimated to have been 150 cm tall, and based upon morphology of the cranial and postcranial skeleton and examination of tooth wear, the to have been over 52 years old. The male is estimated to have been 168 cm high and 30-40 years old. Radiocarbon dating of a piece of charcoal from the grave of the female individual gave a date of 540 years before the present, consistent with the mid sixteenth century, when the first contact (and conflict) between the Spanish and the Mapuche occurred.

The female is missing both hands and the lower part of the left arm, and has as grave goods the calcaneus and astragalus of a Horse (another sign of contact with the Spanish), and a sharpened partial metatarsus of a South Andean Deer, possibly as a replacement for the missing limb portions. She also has a curved transverse fracture on the left ulna, with a regular border, stepped and with crushed edges, and associated with a longitudinal fracture, and an s an incomplete oblique fracture of the medial portion of the humeral diaphysis. The damage to the right left radius is consistent with a spiral fracture, although the preservation of this bone is not good enough to be certain.

The male also lacks the left hand and the lower part of the left forearm, with a spiral fracture on the e medial diaphysis of the left radius, with the broken edge of both the radius and ulna showing signs of crushing and scaling. Another incomplete fracture is present on the right ulna.

Diagram of skeleton, anterior view. Individual 1♀ and Individual 2♂, respectively. The locations of the lesions are shown in red. Reyes Sánchez & Pérez (2023).

The break to the right ulna of the male skeleton is consistent with a 'parry fracture', i.e. a would suffered while defending against a blow, while the left fibula shows signs of a blunt force injury, probably the result of another blow.

The injury to the left humerus of the female skeleton is consistent with a blunt force injury inflicted while the limb was flexed and rotated, while held in position at the upper end. Such injuries elsewhere have been interpreted as signs of torture, i.e. injuries deliberately inflicted on an individual while they are restrained. 

Both individuals have lost the lower part of their left arms, and both show signs of blunt force trauma to the remaining portion of the bones of the lower arm. This is unusual, and blunt-force injuries do not usually remove portions of limbs. While the injuries produced by sharp blades and blunt objects are generally quite different, prior observations have suggested that heavy axe blows can sometimes produce a hybrid injury, both crudhing part of a limb and hacking off the portion below the site of the blow. This appears to be entirely consistent with the injuries to the limbs of both individuals. 

The injuries to these individuals appear quite different to those seen in individuals injured in conflict settings; instead they show injuries consistent with having been brutalised while being tied down or otherwise restrained. 

Prior to contact with the Spanish dismemberment seen in skeletons was consistent with one of two causes; injury in battle, or post-mortem dismemberment for ritual purposes. Notably, in late pre-contact Andean societies, port-mortem dismemberment of bodies to make war trophies was a common practice, as are pre-death blunt force trauma injuries, particularly to the head area, and cuts on the bones of the neck from where the throat was cut.

The arrival of the Spanish in the Americas brought new technologies and practices of injuries to the area. In southeastern North America, the Gulf of Florida, and Peru, this has been shown to manifest in the widespread execution-style killing of both adults and children, pre-death injuries including pre-death blunt force injuries, lessons caused by blunt-sharp blows, and injuries caused by firearms.

Documents made by the Spanish themselves during this period record captured leaders being tied to tree-trunks and tortured by mutilation, who then had their wounds cauterized before being set free, with the intention that they would live long enough to return to their people and display the traumatic injuries, spreading general alarm. This practice appears to have been carried out on a massive scale, with producing large piles of severed limbs and other bodyparts. One notable form of torment was to disarticulate the hand from the forearm, leaving it dangling by a tendon. Notably, such a practice can be achieved without leaving and cuts on the bones, as can other forms of torture known to have been used during the Spanish invasion, which could therefore also potentially have been used on the Newen Antug individuals.

Engravings by Théodore de Bry showing mutilations of hands and noses (bottom) and torture (top) applied by Spanish soldiers to indigenous people in America. Reyes Sánchez & Pérez (2023).

In 1552 and 1553, Spanish troops under r Francisco de Villagra are known to have passed through the Neuquén Andean lake district, engaging in a number of conflicts with the local population, which resulted in heavy casualties on both sides. 

The two individuals buried at Newen Antug appear to have been members of the community held in high regard, who were buried with special care with symbolic artefacts emphasizing their leadership roles. 

Reyes Sánchez and Pérez interpret the injuries suffered by these two injuries as indications that they were taken hostage by the Spanish, and subjected to torture and mutilation whilst restrained, particularly to the left hands and forearms. Both left arms appear to have been struck with sufficient force to split the arm in two, with the injury most likely caused by a blunt axe impacting at an angle of about 45°. These injuries almost certainly lead to the deaths of their victims, but probably not straight away, something consistent with Spanish records of prisoners being tortured and mutilated before being released to spread fear in their communities.

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Sacrificed hands from the Avaris Palace in northeast Egypt.

Understanding historical information can be difficult, especially when only a very limited number of sources of information are available. Much of what we know about life in Ancient Egypt derives from illustrations on temple and tomb walls, as well as papyrus documents from the same settings. This is unlikely to give us a completely unbiased view of life in these times, making other sources of information particularly valuable. Accounts of Egyptian military victories in the New Kingdom, from the 18th, 19th, and 20th dynasties, refer to victorious soldiers presenting severed right hands to the Pharaoh as trophies, receiving in return 'gold of honour', thought to have been a ceremonial necklace of golden beads. This story is, however, known only from inscriptions in the tombs of the warriors that received this honour, and may therefore be allegorical. 

In 2011 excavations at the Tell el-Dab'a site (ancient city of Avaris) in the eastern Nile Delta uncovered a series of severed right hands from a Hyksos Period (15th Dynasty) palace, potentially providing support for this practice. 

In a paper published in the journal Scientific Reports on 31 March 2023, Julia Gresky of the Division of Natural Sciences at the German Archaeological Institute, Manfred Bietak of the AustrianArchaeological Institute, Emmanuele Petiti, also of the Division of Natural Sciences at the German Archaeological Institute, Christiane Schefer of Human Biology at University Potsdam, and Michael Schultz of the Institute of Anatomy and Embryology at Göttingen University Medical School, present the results of a bioarchaeological analysis of the Tell el-Dab'a hands, and the implications of this for our understanding of Ancient Egyptian culture and military practices. 

The hands were found within three pits on the forecourt of a Middle Bronze Age (roughly 1640-1530 BC) Hyksos Palace. This palace was built on top of an older, 14th Dynasty, palace, and lasted for much longer, apparently being in use throughout the Hyksos Period. Its most important occupant appears to have been the Hyksos Pharaoh Khayan (who reigned somewhere between 1700 BC and 1580 BC), with numerous seal impressions bearing his mark found in the lowest parts of the pits. The palace appears to have been in use until the Late Hyksos Period, although it apparently lost its status during that time, with a newer palace complex being built further to the north.

Archaeological evidence of severed hands in Hyksos Period Tell el-Dab‘a, Northern Egypt: (A) Nile Delta, Northern Egypt and position of the site Tell el-Dab‘a/Avaris in the Nile Delta. (B) Northern part of the Hyksos Palace at Tell el-Dab‘a, Phase E1-D3. (C) Overview of the area of Pit L1542 and 1543 (red circle), the excavation layer closely beneath the modern surface in the agricultural area. (D) South wall of a later added broad-room building built against the western enclosure wall of the palace’s forecourt. Pit L 1777 in front of the throne room (indicated by the arrow). (E) Overview of the 11 right hands in the Pits L1542 and L1543. (F) Single right hand on its palm with wide-splayed fingers. Manfred Bietak in Gresky et al. (2023).

The smallest of the three pits, L1777, is directly in front of the throne room, and contained a single articulated hand. This was sealed beneath the south wall of a later building, probably a temple constructed at the west end of the palace forecourt. The pit actually appears to have been dug into a foundation trench for the later temple, cutting through a layer of loam-mortar at the base of the trench. Two further pits were discovered 7 m to the north east of this wall, covered by modern agricultural land. These pits are in alignment with the enclosure wall of the original courtyard, and contain no material which can be ascribed to after the Hyksos Period. One of these pits. L1524, contains the remains of three hands, while the other, L1543, contains the remains of eight hands. Thus between them, the three pits contain the severed right hands of 12 individuals. A number of disarticulated fingers are also present.

The hands appear to have been left exposed for some time after their deposition, rather than actively buried, and the bones are subsequently heavily eroded, with cracking and flaking. The soil from which they were extracted was humid, adding to the problems of excavating the bones, which were soft and brittle. All of the hands and isolated fingers could be identified as being from the right. Pit L1777 contains a single complete right hand, Pit L1542 contains two right hands, plus an individual finger from a third hand, indicating the right hands of at least three individuals were placed in this pit. Pit L1543 contains eight complete or near-complete right hands, plus a number of detached phalanges, from which Gresky et al. conclude that the hands of at least twelve individuals were placed in the pit.

Of the eleven complete right hands, eight were placed with their palms down, and three with their palms up. The individual fingers and partial hands are presumed to have been disturbed from their original resting places. Several of the hands had their first digit twisted into a position which would indicate a severe dislocation in a living individual. 

Anthropological reconstruction of the finding and details of the right hands of pits L1542 and L1543: reconstruction of the complete hands in the pits L1542 (left upper corner) and L1543 (lower half of the picture). Yellow hands are placed on their dorsal surface whereas the red ones are placed on their palms. The missing elements are reconstructed. (A), (C)–(F) eight right hands of Pit L1543, together with single phalanges which could either represent additional hands or might belong to the present hands. The preserved bones are coloured. (B) Three right hands on their palms in Pit L1542. The preserved bones are colour. Julia Gresky in Gresky et al. (2023).

Some disturbance of the hands appears to have happened after their deposition; as indicated by the disarticulated state of some of the fingers, and the individual fingers present, which presumably were either removed from intact hands or represent hands which have otherwise completely disappeared. This could be due to the activities of Rodents, but there are no signs of any gnawing on any of the bones so this seems unlikely. The most likely explanation is that the pits were left open after the hands were deposited in them.

The majority of the hands in the pits are in a flattened position, which suggests that they were either placed this way, or flattened out by soil being compacted on top of them as they were buried. Since the evidence suggests that the hands were not covered up soon after their deposition, it seems plausible that they were deliberately placed in a flattened, splayed position, perhaps to make the display more impressive, although there is no evidence of the hands being organized in any other way, with their positioning within the pits being apparently random. 

Six of the hands have the proximal carpel row of bones preserved, and none of these show any cut marks or signs of tissue removal, and fragments of forearm were located in any of the pits, indicating the process by which the process by which the hands were removed from the lower arm was a precise one. This can be achieved by cutting into the joint capsule and cutting through the tendons as they intersect the wrist joint, although this requires a high degree of skill on the part of the operator. Any error during this process is likely to leave cut marks on the bones of the severed hand. Generally speaking, when people wish to amputate a hand, and aren't particularly concerned about the survival of the owner of that hand, then they simply hack through the bones of the lower arm. This is fast and easy, but leaves a portion of the lower arm attached to the hand. This cannot be ruled out in the case of the Avaris hands, but if this was the case, somebody took care to remove the arm fragments from the hand in a precise way later.

Hands can, of course, be collected both from the living and the recently deceased. Whichever was the case at Avaris, the hands must have been soft and flexible when they were placed into the pits. This implies that either the hands were placed before rigor mortis had set in, or after it had passed. Rigor mortis tends to begin affecting hands about 6-8 hours after death, and passes after 24-48 hours. Therefore, either living victims were mutilated shortly before the hands were placed into the pits, or, more likely, they were collected elsewhere and stored for a while before being placed into the its. 

All of the examined hands have ossified epiphyseal lines, which does not occur til adulthood, but none showed any signs of age-related illnesses, implying that the individuals from which they were removed were probably over 20, but had not reached old age. It was not possible to carry out a genetic analysis of any of the hands, but based upon there size and morphology, implies that all bar one of the intact hands were removed from adult males, with the one exception being removed from an adult of unknown sex.

The hands at Tell el-Dab'a could have been removed as a punishment, or collected from a battlefield as trophies, as a way of demonstrating a military achievement. However, the practice of removing hands as a punishment is not recorded in any known Egyptian text, 

The positioning of the pits at the entrance to the palace complex implies that the ceremonies in which things were placed in them were public ones. This supports the idea that the hands were being ritually presented to the Pharaoh in a ritual similar to that described in later New Kingdom texts, confirming this practice did take place, and extending the time window for the activity back to the 15th Dynasty (about a century before the advent of the 18th Dynasty and the founding of the New Kingdom).

The fact that neither any cut marks nor any part of the lower arm was found associated with any of the hands implies that the hands went through a careful preparation process before being deposited. The majority of the hands were found lying face down with their fingers splayed out, which Gresky et al. believe is likely to have been the original position of all the hands, with those found in other positions showing signs of subsequent disturbance. Had this been the case, it would have been easy for anyone looking into the pits to have identified each item as being a single right hand, therefore representing a single individual.

All of the hands came from adults, but none of them from anyone of great age. Furthermore, all, or almost all (depending on the origin of the single ambivalent hand), were male. This makes it quite possible that these were hands taken from defeated enemy warriors, the majority of whom are likely to have been male (warrior women were not unknown in the ancient world, so the uncertain hand might represent a degree of flexibility in selecting hands for the ritual, but there is no way of knowing if this was the case).

The disarticulated nature of the remains, combined with the absence of any genetic evidence, makes it impossible to determine from whom the hands the hands were taken. However, the find does point towards the Hyksos as having introduced the custom of ceremonially taking the right hand of defeated foes to Egypt, considerably earlier than the oldest known description of the practice, in an inscription dedicated to the 18th Dynasty Pharaoh Ahmose. This inscription introduces a new pictogram of a splayed hand with spread fingers, quite different from earlier Egyptian depictions of hands in side view. This pictogram appears to refer to a severed hand. By the time of the 19th Dynasty Pharaoh Merenptah, the Semitic word 'כף', which can be translated as 'hand' or 'palm' was in use, again apparently referring specifically to severed hands, something which persisted through the 20th Dynasty.

Iconographic evidence of severed hands: inscription in the tomb of Ahmose at El-Kab depicting a very realistic representation of an outstretched palm, showing five spread fingers. William Vivian Davies in Gresky et al. (2023).

The evidence presented by Gresky et al. appears to promote a strong connection between the Hyksos (15th) Dynasty and the introduction of hand-severing as a practice. Gresky et al. note that records of Egyptians mutilating the bodies of their enemies go all the way back to the 1st Dynasty Pharaoh Narmer, but specific references to hand-taking all date to after the Hyksos Period. Subsequent to this, seals commonly depict rows of severed hands, as well as heads, and the heads of Animals; all of these subjects also appear in roughly contemporary Middle Bronze Age inscriptions from Syria. 

The taking of bodyparts as trophies is known from across the world. The Tell el-Dab'a example apparently included a distinct element of presentation to this practice, with the taken hands apparently being publicly displayed outside the Pharaoh's palace, and the severed hands presumably increasing the Pharaoh's status, by indicating military prowess and dominance over nearby states.

Physical dismemberment and mutilation are widely recorded in Egyptian inscriptions, and are commonly combined with accounts of war and conflict. Many inscriptions depict piles of severed heads, ears, and/or genitals, suggesting a codified way of removing these bodyparts, apparently demonstrating the authority of the Pharaoh, and his ability to defend the country against chaos by defeating his enemies, something which needed to be visibly recorded in a way that his subjects could see it.

The taking of right hands is clearly a variant on this, demonstrating the defeating of enemies, in a way that would rob them of the future ability to carry out attacks upon the kingdom, as well as to perform many ordinary daily activities. It is unlikely that the people from whom the hands were taken were captured and used as slaves, since slaves mutilated in this way would have been all but useless. More likely the hands were removed after the death of their owners, which, given Egyptian views on the afterlife and the need to preserve the body intact, would still have been an alarming punishment.

The way in which the hands have been carefully prepared and placed suggests that the motivation for this was not linked to law enforcement. Instead, these appear to be trophies taken in (or after) battle, and subsequently displayed in public. The hands identified came from eleven males and one possible female victims, which may indicate that women were involved in warfare at the time, although this is hard to prove. The ritual which took place here appears to have been connected to the 'gold of honour' ritual performed in the New Kingdom, in which successful military leaders presented severed hands to the pharaoh in return for decorations.

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Searching for dental caries in South African fossil Hominins.

Dental caries (the formation of cavities in teeth through decay of the enamel, through the activities of Bacteria) is common in many modern Human populations, and is generally associated with a diet rich in plant-derived foods rich in sugars and starches. The presence of widespread dental caries in Human populations is generally thought to have come about during the Neolithic, when the cultivation of grains was adopted, providing a source of food reliable enough to allow populations to rise and more complex cultures to develop, but at the same time exposing people to the hazards of a starch-rich, grain-based diet. If this is the case, then instances of dental caries should be relatively rare in Pleistocene Humans, as well as in other Hominin species. 

Modern dental caries is generally associated with the Bacterium Streptococcus mutans, which thrives in the mouths of people with restricted diets, and less diverse oral microbiotic ecosystems, and which is thought to have become particularly prevailent since the industrial revolution. However, a wide range of Bacteria can cause such damage, and in some cases combinations of Bacteria, which in themselves do little damage, can cause problems. Notably, different types of damage are associated with different Bacterial species, or combinations thereof. Damage is typically caused by Bacteria producing acids which the saliva cannot buffer, resulting in erosion of the tooth material. Some foodstuffs are particularly prone to causing caries, notably products with high levels of refined carbohydrates and sugars, but also some natural foods such as fruits, honey, and some nuts and seeds. Instances of carries are far lower in people with diets rich in tough fibrous foods, which promote saliva formation, as well as diets rich in seafood or meat.

Environmental and genetic factors also appear to play a role in the prevalence of dental caries, although it is unclear how. Different populations with similar diets are known to have different rates of dental caries, although the causes of this are unclear. Instances of caries are well known in both archaeological and fossil dental collections, with the varying prevalence of the condition in different agricultural populations fairly well studied. The condition is also known to affect non-Human Primates, with captive populations more affected than wild populations.

In a paper published in the South African Journal of Science on 29 March 2021, Ian Towle of the Sir John Walsh Research Institute at the University of Otago, Joel Irish of the Research Centre in Evolutionary Anthropology and Palaeoecology at Liverpool John Moores University, and the Evolutionary Studies Institute and Centre for Excellence in PaleoSciences at the University of the Witwatersrand, Isabelle De Groote of the Department of Archaeology at Ghent University, Christianne Fernée of the Department of Anthropology and Archaeology at the University of Bristol, and the Department of Archaeology at the University of Southampton, and Carolina Loch, also of the Sir John Walsh Research Institute at the University of Otago, present the results of a study in which they analysed a range of South African Hominin fossils in the collections of the University of the Witwatersrand and Ditsong National Museum of Natural History, including samples of the recently discovered Homo naledi. 

Towle et al. only examined whole teeth, and only considered cases where cavities were clearly present to be evidence for caries; instances of discolouration were considered insufficient evidence due to the nature of the material. Specimens were initially examined with a hand lens, and damage was rated from (1) to (4), using the scheme: (1) enamel destruction only; (2) dentine involvement but pulp chamber not exposed; (3) dentine destruction with pulp chamber exposed; and (4) gross destruction with the crown mostly affected. Finally the location of damage on each tooth was recorded as distal, buccal, occlusal, lingual, mesial, root, or a combination thereof.

The degree of wear (physical abrasion) to each tooth was also recorded, in order to examine the corelation between diet and caries, and to give an estimate of the age of the individuals from which the teeth came (and therefore the age at which they were becoming affected by caries). The front teeth were given a simple wear score from one to eight, with the molars split into four quadrants, each of which was given a wear rating of between one and ten, with an average being used for the whole tooth. Comparisons were made between teeth rather than between individuals, as the majority of the material was in the form of loose teeth, although Towle et al. do recognise that there is a possibility of multiple teeth from the same locarion coming from the same individual, and that it is likely that an individual with caries on one tooth would have it on others.

A subset of the affected teeth were further subjected to computerised tomography scanning at the Department of Human Evolution of the Max Planck Institute for Evolutionary Anthropology, which can differentiate between dentine and enamel, as well as detecting cases of caries where the affected area has reduced density but not obvious cavities. 

Prior to Towle et al.'s work, six cases of dental caries had been identified in Hominin specimens from South Africa, and Towle et al. were able to add another four examples to this; two from specimens of Paranthropus robustus, and two from a single individual of Homo naledi. A total of fourteen examples of caries have now been found in ten teeth from seven Homininss. The seven individual Hominins in which dental caries have been diagnosed comprise five Paranthropus robustus, one Homo naledi, and one 'early Homo'. No evidence if dental caries has been found in any example of Australopithecus sediba or Australopithecus africanus.

One of the previously described specimens, SK 15 (early Homo) interproximal caries on the lower right second molar and left first molar. (a) Overview of specimen; scale bar is 1 cm. (b) Mesial carious lesions (white arrows) and (c) close-up of the right second molar with carious lesion on the mesial surface. Towle et al. (2021).

Homo naledi specimen UW 101-001 shows the worst case of caries ever described in a non-Human Hominin. The cavities present penetrate deep into the dentine, and appear to have been active for a long time. There is no difference in the wear on the teeth affected, suggesting the cavities were not having an impact on mastication function. The cavities are present on the right fourth premolar and first molar, on the surface where these teeth would have faced one-another, implying they had a common cause. In the case of the molar the cavity has expanded to cover much of the occlusal surface, and affected both the root and crown of the tooth. There is sediment present on the surface of the tooth, which accumulated after death, preventing an investigation into how deep the cavity had penetrated into the dentine, and whether it had reached the pulp chamber; it was not possible to subject this specimen to computerised tomography.

UW 101-001 (Homo naledi) carious lesions on the lower right second premolar (distal) and first molar (mesial). (a) Overview of specimen; white arrow shows location of the two interproximal carious lesions; scale bar is 1 cm; (b) Close-up of lesions. (c) Right second and third molars, with two antemortem chips on the mesial buccal corner (white arrow). Towle et al. (2021).

Paranthropus robustus mandible SK 23 also shows occlusal caries on two teeth, in this case the left first molar and right second premolar. Both these teeth show large, dark cavities, though again this is partially covered by a matrix of material that had accumulated post-mortem. This sample did not prove particularly amenable to computerised tomography, although the area under the cavities did appear to be less dense, which would support a diagnosis of dental caries. 

 

SK 23 (Paranthropus robustus). (a) Occlusal view of mandible, with the lesion on the right second premolar highlighted (black arrow). (b) Closeup of the occlusal surface of the right second premolar. (c)  Computerised tomography reconstruction with the position of the two slices highlighted. (d) Computerised tomography slice toward the lingual part of the cavity. (e) Computerised tomography slice toward the buccal portion of the cavity. Towle et al. (2021).

The number of reported cases of dental caries in non-Human Hominins is low, but represents a significant proportion of the available specimens; 1.36% of all Homo naledi specimens, 1.75% of all Paranthropus robustus specimens, and 4.55% of all 'early Homo' specimens. Four of the seven specimens in which the condition is seen had more wear on the occlusal surfaces of the teeth than the average for such teeth, which may be significant, although most had close to the species average wear levels, and little damage to the crown.

 

SKX 5023 (Paranthropus robustus) lower right first molar. (a) Overview of specimen with carious lesion on the mesial surface (white arrow). (b) Close-up of mesial lesion. (c) Occlusal view of the specimen. (d) Occlusal/mesial view of specimen showing the carious lesion, antemortem chip (white arrow) and cupping dentine wear (white star). Both scale bars are 1 cm. Towle et al. (2021).

These results suggest that caries may have been more common in pre-agricultural populations than has generally been assumed, and that the condition was relatively common in some South African Hominins, and therefore presumably in Hominins in general. In modern dentistry, visual diagnosis is generally backed up with X-rays, physical probing, and observation of colour changes in teeth, but taphonomic changes make these approaches less useful in palaeontological and archaeological material. Towle et al. were able to examine a small number (five) of specimens by computerised tomography, with mixed results, and it will be necessary to apply this method to more specimens in order to judge how useful in can be.

 

DNH 40 (Paranthropus robustus) upper left third molar. (a) Overview of the tooth, showing mesial and occlusal surfaces (carious lesion indicated by white arrow); scale bar is 1 cm. (b) Close-up of mesial lesion. (c) Computerised tomography slice of the specimen; white arrow indicates the carious lesion. Towle et al. (2021).

Bacteria capable of causing caries appear to have been a problem for many, possibly all, Hominin species. This is consistent with recent work which suggests a wide range of Bacteria are capable of causing such damage, either on their own or in concert with other species; in the latter case the Bacteria involved may otherwise be a part of a normal, non-pathological, oral biota. This suggests that the major cause of dental caries is not, in fact the type of Bacteria, but rather the diet of the individual, which in turn implies that we can make judgements about the diets of extinct Hominins by the presence and prevalence of dental caries, although differing oral microbiomes in different Hominin species may have made them more, or less, vulnerable to dental caries under similar conditions. 

Caries on the occlusal surfaces of teeth is not associated with high rates of tooth loss, whereas caries on the interproximal surfaces (surfaces that face other teeth) is. Interproximal caries is often associated with the accumulation of plaque in these areas, which does not appear to be a factor in any of the South African Hominins. Enamel hypoplasia (poor formation of the enamel during development) is another major cause of vulnerability to dental caries, and may have been a factor in the cases of the Paranthropus robustus specimens SK 55 and SK 13/14, both of which show substantial hypoplastic pitting; something common in this species.

Dental caries may also develop as a response to damage or unusual wear patterns, which may create weaknesses in the tooth enamel, or spaces in which Bacteria can accumulate safely, and Towle et al. note that this appears to be present in several of the specimens in which they detected the condition. 

Chewing on hard items, such as grit in food, can cause damage to teeth which leaves them vulnerable to infection. In Hominins, the interproximal areas of teeth appear to be particularly prone to such damage, unlike in modern Humans, where the occlusal surfaces of the rear teeth are most affected, although the reason for this is unclear.

Modern Human samples, from the last 50 000 years, show levels of caries similar to that detected by Towle et al.; this changes with the adoption of agriculture, and in some populations becomes far more common. An infection rate of 1-5% seems to have been typical for both pre-Human Hominins and Humans leading hunter-gatherer lifestyles. Therefore, the occurence of caries appears to be strongly linked to behaviour and diet, rising in agricultural societies, but also in hunter-gatherer societies with certain diets.

The absence of dental caries observed in Australopithecus africanus is unlikely to reflect a radically different oral microbiome. Instead, this may be a result of a different diet, or simply sampling bias. The presence of the condition in Paranthropus robustus, Homo naledi, and 'early Homo' indicates that these species were consuming foods which made them vulnerable to the condition. Dental caries is also fairly common in species assigned to the genus Homo from elsewhere (including Neanderthals), suggesting that members of the genus have eaten dangerous foods (such as tubers, nuts, plants or fruit) since they first appeared.

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Using high-resolution computed-tomography to study pathologies in Belemnites.

The term pathology refers to malformations of specimens of a population or species that are caused by exogenic or endogenic processes. Exogenic processes include injuries due to a predator attack, parasite infections, and the colonisation of the shell during lifetime. Endogenic processes include infections, mutations, or other illnesses. The term palaeopathology is used pathological features of fossils. To ensure accurate palaeoecological interpretations it is required to distinguish between pathologies and pseudopathologies, e.g. tectonically deformed Belemnite rostra. Fractures of tectonically deformed rostra are filled with blocky calcite cement instead of biogenic radial fibrous calcite. Such rostra, therefore, do not contribute to our understanding of Belemnite palaeoecology. The visible reactions of an affected specimen are called symptoms while several abnormalities that occur in a single specimen are described as complex syndromes. As a rule, only reactions to the disturbing factor should be considered to characterise pathological symptoms or syndromes. The disturbing factor (pathogen) underlying the palaeopathological features of fossil hardparts is only rarely identified. In exceptional cases, specific bite traces with a distinct shape or morphology of shell breakage are preserved and allow the identification of specific producers such as Crustaceans, Coleoids, Fishes, or Reptiles.

Pathologies of modern and fossil Cephalopods have received proportionally large attention. The first reports on malformed Cephalopods were made by Johann Samuel Schröter in 1774, although he did not recognise them as such. Later, pathological specimens were regarded as monstrous natural curiosities. Later, pathological specimens were regarded as monstrous natural curiosities. The potential factors causing abnormal morphologies were first discussed in the 1890s. Consequently, exploration of the disturbing factors was increasingly used to reconstruct the palaeobiology and palaeoecology of the affected specimens and helped in reconstructing phylogenetic processes. 

Due to their internal shell, Coleoid Cephalopods such as Belemnites are not affected by epizoans that settle on the external shells of Nautiloids or Ammonoids. In externally shelled Cephalopods, damage to the phragmocone can result in uncontrolled flooding of the chambers, which in turn leads to lethal drowning by shell implosion. In contrast, the internal shell of Coleoids often remains in the mantle sac after being fractured. In case the animal survived the attack, damaged skeletal parts are often successfully repaired.

Data gained from palaeopathological studies of Cephalopods helped in estimating the efficiency of the buoyancy apparatus. Synecological factors can be reconstructed by the recognition of parasite infections or the presence of epizoa which in turn helped to reconstruct potential habitats and life habits. Lethal or sublethal injuries also add information on predator-prey interactions. Recent studies have provided a detailed overview on palaeopathological Belemnite rostra and introduced forma aegra-types for recurring kinds of abnormalities following the scheme developed for Ammonoids. It should be noted that forma aegra-types do not refer to taxonomic entities but are a type of open nomenclature for the classification of pathologies. For fossil coleoid cephalopods, including belemnites, three categories of palaeopathologies can be distinguished based on their causes: (i) regeneration of injuries including inflammatory infection often caused by an unsuccessful predatory attack, (ii) prod traces due to collisions, (iii) parasite infection.

Most malformations of Belemnite rostra resulted from mechanical injuries, often caused by failed predation attempts, and less commonly from parasite infestations. It has been argued that rostra broke due to mechanical stress induced during active digging in the sediment with the rostrum. Due to the likely nektic lifestyle of belemnites and the counterweight function of the rostrum that allows a horizontal swimming position, injuries due to digging are highly unlikely.

In a paper published in the journal Acta Palaeontologica Polonica on 24 March 2020, René Hoffmann and Kevin Stevens of the Institut für Geologie, Mineralogie und Geophysik at the Ruhr-Universität Bochum, Marie-Claire Picollier of St. Pantaly d’Excideuil, Jörg Mutterlose, also of the Institut für Geologie, Mineralogie und Geophysik at the Ruhr-Universität Bochum, and Christian Klug of the Paläontologisches Institut und Museum at Universität Zürich, demonstrate that nano-computed-tomography scanning of pathological Belemnite rostra provide data with an excellent resolution, allowing a detailed description of internal features including malformations.

High resolution and good signal to noise ratios in the resulting computed-tomography-images are important for the successful study of pathological belemnite rostra because of the continuous deposition of concentric growth increments. That mode of growth resulted in a successive attenuation of the primary morphology of the injury and the resulting symptom due to the deposition of post-traumatic growth increments. Based on computed-tomography-data, Hoffmann et al. provide short descriptions of the different types of palaeopathologies and discuss their potential causes. Furthermore, they demonstrate additional applications such as the recognition of a heterogeneous or homogenous composition of Belemnite rostra due to diagenesis, sedimentary fill, structures of the rostrum surface, and internal structures of the phragmocone such as septal spacing and the position of the siphuncle.

A total of 18 pathological belemnite rostra from Lower Jurassic (Toarcian) to Upper Cretaceous (Campanian) deposits, were computed-tomography-scanned. The material can be attributed to the following genera (in alphabetical order, number of studied specimens in parenthesis): ?Acrocoelites sp. (1), Belemnellocamax spp. (4), Belemnitella sp. (2), Duvalia emerici(1), Goniocamax sp. (1), Gonioteuthis spp. (5), Hibolithes jaculoides (2), Neoclavibelus subclavatus (1), and Pseudobelus sp. (1).

Hoffmann et al. describe various pathologies encountered according to their morphological expressions including two-tipped specimens, blisters and pearls, broken rostra, which healed straight, rostra with a kink or bent rostra. Differences in grey scale values in the images suggest different materials such as calcite, silica, pyrite, or sediment. The growth increments of the rostrum, for example, are visible in computed-tomography-images due to the varying amount of organic matter, which has significant lower absorption properties compared to pure calcite. This implies that organic-rich growth increments are darker compared to those composed of pure calcite.

Rostrum of Belemnite ?Acrocoelites sp., PIMUZ 37346, Toarcian, Altdorf (southwest-Germany) with apex malformation. (A) Overview (A₁), (A₂). (B) Close-up of the two apices, showing the radial furrows covering the apex that represent the 'normal' tip of the rostrum (B₁)–(B₅). Hoffmann et al. (2020).

One ?Acrocoelites sp. specimen (PIMUZ 37346) and one Gonioteuthis sp. specimen (RUB-Pal 11264) rostrum are characterised by two divergent apices. In both specimens one apex represents the continuation of the original rostrum axis and bears radial striation on its outer surface. The second apex of ?Acrocoelites sp. bears one strong dorsal furrow. Superficially, the arrangement of the ?Acrocoelites sp. apices resembles a crustacean claw. Unfortunately, the computed-tomography-data did not reveal the course of growth increments or other internal structures, which suggests an irregular formation of the skeletal calcite.

Rostrum of Belemnite Gonioteuthis sp., RUB-Pal 11264, Campanian, Höver (northwest-Germany) with apex malformation. (A) Surface images showing the hollow opening of the two apices, and the partially dissolved or poorly mineralized rostrum (A₁)–(A₆); arrow in (A₅) indicates meandering trace fossil. (B) Longitudinal section showing growth increments, apical line, and irregular mineralized layers (B₁), (B₂). (C) Cross sections with increasing distance to the apices (C₁)–(C₈), showing the process of apex separation, only the straight continuous apex (arrows) develops distinct growth increments and the apical line (see also the arrow in B₂), note: the area between the apices is filled with sediment (diffuse grey area) and pyrite (white area), black area silicified. Hoffmann et al. (2020).

The continuation of the normal rostrum growth in the Gonioteuthis sp. is supported by the presence of the apical line and growth increments. The rostrum surface of this Gonioteuthis sp. partially shows dissolution features or poorly mineralized layers exposing triangular structures. Some of these features suggest the presence of meandering trace fossils. Both apices were partially hollow and subsequently filled with sediment. Development of the two apices is reflected in the image series based on virtual cross sections. Areas darker than the calcitic parts of the rostrum and mostly restricted to the rostrum surface indicate the presence of silica.

One Neoclavibelus subclavatus (SNSB-BSPG-83264) and one Belemnitella sp. (RE 551.763.333. A 5238) rostrum each show a bump-like structure. Virtual cross sections of the Neoclavibelus subclavatus rostrum reveal the presence of sediment inside the rostrum. This debris was subsequently overgrown by calcite precipitated by the Belemnite, causing the malformation. The longitudinal section shows that the contaminant covers parts of the juvenile rostrum, thereby causing a deviation in growth increment orientation. White areas suggest the presence of pyrite, which completely absorbs the X-rays. The bump-like structure in the Belemnitella sp. rostrum was probably caused by a similar process. In this case, the foreign material caused the bending of dorsolateral depressions covering the rostrum surface. Darker areas along the margin of the rostrum suggest the presence of silica. For both species, Hoffmann et al. also provide high-resolution computed-tomography-images. A large part of the Goniocamax sp. rostrum shows signs of exfoliation. Hoffmann et al.'s computed-tomography-based examination of the area where outer rostral layers thin out reveals, that sediment was deposited between distinct growth increments of the belemnite rostrum. Both specimens show hollow areas, partially filled with carbonate crystals, within the rostrum forming blisters. The Goniocamax sp. blister is elongated with a spiral morphology. The sediment filled blister contrasts with the massive bump-like structures of another two specimens, undetermined specimen CASP K9068 and Duvalia emerici. The undetermined rostrum shows a distinctive layer from which the growth perturbation starts in longitudinal- and cross section. This structure resembles the phenomenon described for Neoclavibelus subclavatus and Belemnitella sp. For Duvalia emerici, no such perturbation has been identified.

(A) Rostrum of Belemnite Neoclavibelus subclavatus, SNSB-BSPG-83264, Toarcian, Mistelgau (southwest-Germany) with blister malformation. Surface images showing the bump-shaped irregular rostrum growth (A₁)–(A₄); longitudinal sections showing presence of sediment (diffuse grey) and pyrite (white) within the rostrum, and increasing irregular growth increments (A₅), (A₆). (B) Rostrum of Belemnite Belemnitella sp., RE 551.763.333 A 5238, Late Cretaceous, northwest-Germany with forma aegra bullata (coll. Baschin). Surface images showing the bump-shaped irregular rostrum growth and imprints of an organic network on the rostrum surface in dorsolateral (B₁), (B₂) and ventrolateral (B₃), (B₄) views; longitudinal sections (B₅), (B₆), and cross section (B₇). (B₅)–(B₇) showing silification (black) along the rostrum surface but also along the malformed area. Hoffmann et al. (2020).

One Belemnite assigned to Gonioteuthis sp. (RUB-Pal 11301) and one assigned to Hibolithes sp. (RUB-Pal 11303) have fractured rostra. Due to strong silification, the results from the computed-tomography-scans remain inconclusive for the Gonioteuthis sp. rostrum. The apical line appears to form a continuous line without the formation of a blunt rostrum. Parts of the rostrum increments seem to be poorly mineralised, causing parts of the juvenile rostrum to stick out where normally the alveolus is situated. This example demonstrates the potential of the computed-tomography technique to better understand the mineralogical composition of Belemnite rostra. In Hoffmann et al.'s specimen silification rings correspond to darker areas in virtual section images. Virtual sections of the Hibolithes jaculoides rostrum reveal a broken juvenile rostrum with the apex missing. The fracture was overgrown by irregularly formed rostrum material. While the outer layers show regularly formed growth increments, the internal part appears to be chaotic without forming an apical line. This irregular growth results in a rostrum morphology comparable to the genus Produvalia.

(A) Rostrum of Belemnite cf. Hibolithes jaculoides, SNSB-BSPG-83251, Hauterivian, Heligoland (north-Germany) with blister malformation. Surface images showing the bump-shaped irregular rostrum growth, in lateral (A₁), dorsal (A₂), lateral (A₃), and ventral (A₄) views. Longitudinal section showing open pore space partially filled with carbonate cements (A₅). (B) Rostrum of Belemnite Goniocamax sp., MGUH 32024, Santonian, Bavnodde (Denmark) with blister malformation. Surface images of the rostrum showing the bump-shaped irregular rostrum growth (B₁)–(B₄). Longitudinal section with growth increments, apical line, and the bump-like structure with pore space (black) (B₅). Cross section through the malformed area showing the pore space partially filled with carbonate cement (B₆). Marginal section through the malformed area (B₇). (C) Undetermined Belemnite, CASP K9068, Greenland, Early Cretaceous with blister malformation. Surface images of the rostrum showing the irregular rostrum area (C₁)–(C₃). Longitudinal section showing growth increments, apical line and a distinct growth increment at which the malformation starts (C₄). Cross section that shows the distinct growth increment, and a horizontal fracture (white), as well as grains of pyrite (white) (C₅). (D) Rostrum of Belemnite Duvalia emerici, RUB-Pal 22170, Late Valanginian, Laborel (France) with blister malformation. Surface images of the rostrum showing the irregular rostrum area (half-pearl shaped), in ventral (D₁), lateral (D₂), (D₃), and dorsal (D₄) views. Longitudinal section through the malformed area (D₅). Cross section, both section reveal that the structure is massive, i.e., not a blister pearl (D₆). Hoffmann et al. (2020).

Two specimens of Gonioteuthis spp. display a marked distortion of the rostrum. Both, the rostrum and the phragmocone were affected in one specimen, post mortem overgrown by an Oyster In this case parts of the juvenile rostrum are not preserved (RUB-Pal 11302). The rostrum surface shows faint radial striae. The second specimen (SNSB-BSPG-83246) yields an intact phragmocone but parts of the juvenile rostrum broke off. The phragmocone is partially filled with pyrite (white area) and sediment (irregular greyish). Due to partial silification, the growth increments are well visible. Areas with strong bending are silicified, and the rostrum surface is rough due to dissolution, poor mineralisation, or both. Although strongly bent, the rostrum shows growth increments and an apical line.

A. Rostrum of Belemnite Gonioteuthis sp., RUB-Pal 11301, Campanian, Höver (northwest-Germany) with blunt rostra. Surface images showing no irregularities except for silification rings (A₁)–(A₃). Longitudinal section showing a homogenous internal rostrum with a dark layer along its outer margin (silica) (A₄). Volume rendering image shows a darker centre due to the maximum thickness of the structure but no additional features (A₅). Detail of the rostrum surface showing silification rings (A₆). Cross section with a homogeneous centre and a dark margin (A₇). (B) Rostrum of Belemnite Hibolithes jaculoides, RUB-Pal 11303, Hauterivian, Resse (northwest-Germany) with blunt rostra. Surface images showing the overall irregular rostrum morphology and the blunt and hollow apex in lateral (B₁), (B₂), ventral (B₃), and dorsal (B₄), apical (B₇) views. Longitudinal sections (central, subcentral) showing the broken juvenile rostrum, parts of the preserved phragmocone, and notable the lack of the apical line after the injury took place, note the irregular outline of the hollow central canal (B₅), (B₆). Cross section with the juvenile rostrum, and subsequently deposited homogeneous material, white areas indicate the presence of pyrite (B₈). Hoffmann et al. (2020).

One rostrum each of Gonioteuthis sp. and Pseudobelus sp. are strongly distorted resulting in a change of growth direction. The specimen of Gonioteuthis sp. (SNSBBSPG-83370) deviates from the normal (straight) growth direction by about 90° with its apex pointing slightly towards the alveolus. A small part of the phragmocone, now filled with sediment, is preserved and the rostrum is heavily silicified. A few growth increments and a faint trace of the apical line are visible. The rostrum of Pseudobelus sp. (RUB-Pal 3196) shows the strongest deformation reported here. Computed-tomography-data suggest three traumatic events resulting in fractures and finally a reversion of the growth direction towards the head of the animal. Growth increments and apical line are, however, well visible in the longitudinal section. The cross-section image shows four growth zones representing a temporal sequence implying that the rostrum broke during four successive and independent events.

Rostra of Belemnite Gonioteuthis spp. (A) RUB-Pal 11302, Campanian, Höver (northwest-Germany) with bent rostra. Surface images showing the knee-like morphology of the rostrum, and the attachment-base of an Oyster, in lateral (A₁), (A₄), dorsal (A₂), and ventral (A₄) views; note the weak furrows in (A₃). Median sections perpendicular to each other showing silicified areas (darker) and the broken phragmocone now filled with sediment, no additional internal feature visible (A₅), (A₆). (B) SNSB-BSPG-83246, Campanian, Höver (northwest-Germany) with bent rostra. Surface images showing the knee-like morphology of the rostrum, in ventral (B₁), lateral (B₂), (B₄), and dorsal (B₅) views. Cross section (B₃). Median sections showing silicified areas specifically at places heavily bent (darker) (B₆), (B₇); see also (A₅), (A₆) for the same phenomenon. Black box indicates close up in (B₇), showing the broken juvenile rostrum with growth increment (bent rostra), and the phragmocone partially filled with pyrite (white). Hoffmann et al. (2020).

Four malformed specimens of Belemnellocamax sp. with fractured rostra show weak to strong reactions that occurred during the healing process. One specimen (GM 04.1918) is a knee-like bent rostrum with a spongy, highly porous internal structure. A second specimen (GM 02.1918) has a short rostrum with a blunt apex due to a spherical depression. The virtual section reveals a broken juvenile rostrum associated with a porous area surrounding it. The third specimen (GM 01.1918) also has a broken juvenile septum, which extended beyond growth increments of older parts of the rostrum. Subsequently formed growth increments never covered the juvenile rostrum entirely, forming a callus-like structure. Parts of the alveolar region are preserved allowing for a correct orientation of the rostrum. Specimen four (GM 03.1918) shows a slightly irregular rostrum morphology with curved depressions and a small hole on the rostrum surface. Virtual longitudinal sections reveal that the hole at the surface is connected to a canal that appears to start in the central alveolar region. Growth increments, otherwise well visible, disappear around the canal.

(A) Rostrum of Belemnite Gonioteuthis sp., SNSB-BSPG-83370, Campanian, Höver (northwest-Germany) with hook-shaped rostra. Surface images showing the knee-like strongly bent and irregular morphology of the rostrum (A₁)–(A₄). Median section showing the irregular internal silification of the rostrum indicating poorly mineralized areas, growth and apical line partially visible (A₅). Volume rendering image with the darkest areas represented by the thickest or densest areas (A₆). (B) Rostrum of Belemnite Pseudobelus sp., RUB-Pal 3196, Valanginian, Barret-Meouge (France) with hook-shaped rostra. Surface images showing the strongly bent and irregular morphology of the rostrum with the apex growth in anterior direction (B₃)–(B₆). Median section overview and close up showing growth increments and the presence of pyrite along the apical line (white) (B₁), (B₇), (B₈). Cross section showing four growth center representing a temporal sequence (B₂). Hoffmann et al. (2020).

Like all Coleoid Cephalopods, Belemnites formed their internal shell within the shell sac. Belemnite rostra were secreted by the muscular mantle that is fused above the shell mantle in Endocochleate Cephalopods. Growth increments are rhythmically added to the rostrum by simultaneous accretion on its surface. This mode of biomineralisation is comparable to the formation of the cuttlebone sheath of Sepiids including the spine, which contains high amounts of organic material. The rostrum is composed of radiaxial calcite fibres that cross the concentric growth increments.

Rostra of Belemnite Belemnellocamax spp., Campanian, Ivo Klack (Sweden). (A) GM 04.1918, collar formation. Surface images showing the knee-like morphology of the rostrum (A₁)–(A₄). Longitudinal section showing the porous apical area (black) (A₅). Alveolar region (A₆). Cross section showing pore space within the rostrum (black) (A₇). (B) GM 02.1918, collar formation. Alveolar region (B₁). Cross section with the juvenile rostrum in its centre (B₂). Rostrum surface of the short, stout rostrum with a blunt apex and a concave impression (?dissolution feature), in lateral (B₃)–(B₆) and apical (B₇) views. Central and subcentral longitudinal section with the juvenile rostrum and the surrounding porous area (B₈), (B₉). Hoffmann et al. (2020).

The recent application of non-invasive imaging methods other than magnetic resonance imaging to Belemnite rostra, such as synchrotron radiation based micro-computed-tomography, revealed the presence of a new rostral ultrastructure, suggesting a composition of two distinct calcite phases. Micro-computed-tomography has previously been used to describe bioerosion features (trace fossils), which are often found on Belemnite rostra, and to determine rostrum volumes to reconstruct temporal changes in Belemnite size. The description of a variety of pathological phenomena highlights the advantage of the higher spatial resolution and suitable contrast properties accessible by computed-tomography-derived volume data to explore the three-dimensional nature of pathological specimens.

Rostra of belemnite Belemnellocamax spp. (A) GM 01.1918, Campanian, Ivo Klack (Sweden) with collar formation. Surface images showing the collar-like structure and parts of the juvenile rostrum (A₁)–(A₄). Longitudinal section (A₅) showing the sediment filled phragmocone with the protoconch, the Klähn’sche plane, the juvenile rostrum, and the material added after the traumatic event forming a collar-like structure but not covering the juvenile rostrum completely. Alveolar region (A₆). Opposite side with the juvenile rostrum sticking out (A₇). (B) GM 03.1918, Campanian, Ugnsmunnarna (Sweden) with fcollar formation. Irregular outline morphology of the rostrum (B₁)–(B₄). Longitudinal section to show the canal, growth increments (B₅), (B₆). Cross section through the apical line and the canal (B₇). Hoffmann et al. (2020).

The following malformation categories were used to group the various types of malformation:

Apex malformation describes a duplication or multiplication (up to five apices known so far) of the rostrum apex. It has been argued that due to traumatic events (mechani cal injuries) or the activity of parasites parts of the apex forming mantle epithelium were separated into locally independent secretion centres that formed several apices. Hoffmann et al. report apex malformations in one specimen of ?Acrocoelites sp. and Gonioteuthis sp. each.

Blister malformation includes blister thickenings of the rostrum often enclosing a hollow space, which may indicate the earlier presence of endoparasites. The locally proliferating mineralization of the rostrum can in rare cases lead to the formation of a second rostrum paralleling the primary rostrum. Hoffmann et al. report blister malformations in one specimen of Neoclavibelus subclavatus, Belemnitella sp., Hibolithes jaculoides, Goniocamax sp., an undetermined Belemnite, and Duvalia emerici each.

Blunt rostra malformation contains more or less club-shaped rostra that are thicker and shorter compared to normal specimens. They are the result of broken juvenile rostra. Depending on the timing and severity of the fracture, slightly to heavily deformed rostra result. Often, the earliest parts of the phragmocone including the initial chamber are affected, Extreme shortenings of the rostrum results in a droplet-shaped morphology. Hoffmann et al. report blunt rostra malformation in one specimen of Gonioteuthis sp., one specimen of Hibolithes jaculoides, and two Belemnellocamax sp. specimens.

Bent rostra malformation is characterised by multiple rostrum fractures. The dislocated rostrum fragments were covered by post-traumatic growth increments. Depending on the size and position of the fragments within the mantle sac, distortions of variable angles (within a plane or a screw-like arrangement of the fragments in different planes) resulted. This phenomenon includes specimens with fragments grown together sub-parallel to each other after the attack. Hoffmann et al. report bent rostra malformation in two specimens of Gonioteuthis spp. and one specimen of Belemnellocamax sp.

Hook-shaped rostra are often the result of rostrum fractures that occurred during early ontogeny. Parts of the broken rostrum become dislocated and post-traumatic growth is preferentially oriented towards one side of the rostrum resulting in a change of growth direction. In cases where the rostrum becomes significantly shorter, a form transitional between the hook-shaped rostra and collar formation exists. A 180° reversal of the growth direction of the rostrum towards the head of the animal due to several fractures is documented by Hoffmann et al. for the first time. Hoffmann et al. report Hoffmann et al. in one specimen of Gonioteuthis sp. and Pseudobelus sp. each.

Sceptre-shaped rostra occur where a mechanical injury of the mantle sac epithelium  leads to a partial lack of growth increments. This is related to the disabled function of the injured epithelium to secrete shell material. This symptom is often observed in the apical area of the rostrum causing an incomplete apex. In this case juvenile, pre-traumatic parts of the rostrum form the apex. A damage of the lateral epithelium is related to a thinning of the rostrum in the affected area and result in a sceptre-shaped rostrum. Hoffmann et al. report sceptre-shaped rostra in one specimen of Gonioteuthis sp.

Collar formation deformation describes flap-like outgrowths at the sub-apical rostrum area without visible injury. This symptom has been reported from a variety of Jurassic and Cretaceous Belemnites and possibly results from a parasitic infestation This infestation caused the formation of a collar that is regarded as an effluence channel and potentially indicates an inflammation of the mantle sac epithelium. Hoffmann et al. report collar formation in one specimen of Belemnellocamax sp.

Most studies about modern Molluscan parasites deal with parasites of Bivalves. Bivalves host a diverse group of parasites and disease-causing agents such as, e.g., Viruses, Prokaryotes, Fungi, Protists, Parazoans, and Metazoans (Platyhelminths, Annelids, Molluscs, Bryozoans, and Arthropods). The most abundant parasites are endoparasitic Flukes (Trematoda, Digenea), which have also been observed in Gastropods. Larvae of Digenean Trematodes (Gymnophallidae) sometimes lead to the formation of blisters and have been found in fossil Bivalves dating back to the Triassic. Blister formation, however, can have a variety of causes, some of which are not due to parasites. Identification of a specific parasite taxon, however, is hampered by the fact that parasites are typically small-bodied (submillimetre) and usually lack biomineralised hardparts.

In modern Cephalopods, parasites are known from many species from all major oceans ranging from coastal, shelf, to oceanic and deep-sea environments. This is no surprise given that Cephalopods are a key trophic element in marine ecosystems. One study documented 200 species of endoparasites in Cephalopods with macroparasites such as Nematodes, Copepods, and Isopods. These predominantly affect non-mineralized tissues such as the digestive tract and the gills. The infestation of mainly non-mineralised tissues limits the fossil preservation potential of parasite activity and the resulting host reaction.

For Belemnites, most reported pathologies are due to survived predator attacks (e.g. bent rostra), a few malformations are assigned to the activity of parasites like, blister malformation, collar formation, and apex malformation. Although Hoffmann et al. identify a parasite infection as the most likely trigger of these pathologies, attributing the deformations to a specific parasite taxon is difficult to impossible. While some parasites leave characteristic patterns on their host, this is not necessarily definitive evidence of their presence. Different parasites can leave similar traces and taxonomically distant parasites can inflict similar symptoms on their hosts because of convergence in the evolution of host-exploitation strategies. Differential diagnosis for palaeopathological phenomena may lead to the conclusion that two or more alternative conditions remain as potential triggers.

Hoffmann et al.'s high-resolution computed-tomography-data represent an innovative and non-destructive way to analyse the internal structure of Belemnite rostra. computed-tomography-images revealed internal structures that allow the examination of a variety of pathological phenomena and to differentiate between different types of pathology. Most importantly, the computed-tomography-data allow to infer potential causes of these deformations (predator attack or parasite activity), therefore going beyond a classification of pathologies from the surface of a specimen alone. Hoffmann et al. thereby demonstrated the usefulness and feasibility of the application of non-invasive imaging methods to the field of palaeopathology. The data gained can be further used for the identification of various diagenetic alteration features in Belemnite rostra. computed-tomography-data turned out to perform better than magnetic resonance imaging-data in terms of spatial resolution and contrast.

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