Papers by Dylan Bastiaans
Here we describe multiple pathological skeletal elements in a specimen assigned to a globidensine... more Here we describe multiple pathological skeletal elements in a specimen assigned to a globidensine mosasaur as Prognathodon cf. sectorius. This individual, NHMM 2012 072, was recovered from the upper Lixhe 3 Member (Gulpen Formation, upper Maastrichtian) near Maastricht, the Netherlands. In all likelihood, it was bitten in the snout by a large, possibly conspecific mosasaur e and survived this attack. The specimen described here is among the very few with clear and unambiguous evidence of (very likely intraspecific) agonistic interactions amongst mosasaurs. Despite significant injuries, including partial amputation of the premaxilla, this animal initially recuperated from the encounter, but the subsequent infectious processes as a result of this attack were still ongoing at the time of death. Radiological and morphological features suggest chronic osteomyelitis which led to loss of bone within the left maxilla, which probably hampered the ability to feed, potentially contributing to its demise. This case study illustrates the potential of integrative three-dimensional approaches in palaeopathological studies to provide a much more comprehensive and detailed description of alterations and underlying physiological processes.
The Arabian fossil potential had been largely unexplored until the last two decades. Although its... more The Arabian fossil potential had been largely unexplored until the last two decades. Although its fossil record has improved considerably in terms of quantity, it still largely consists of poorly preserved undiagnostic material. Here we describe a newly discovered enigmatic ornithopod braincase from the Al-Khod Conglomerate Formation of Oman. This formation fills an important spatio-temporal gap, given its position in between Africa and Eurasia, its long palaeogeographic relationship with Africa and being latest Cretaceous (post-Cenomanian) in age. It has produced one of the most taxonomically diverse latest Cretaceous faunas for any Gondwanan landmass and a significant portion of all dinosaur records from the Arabian Peninsula. The braincase is assigned to Ornithopoda on the basis of: a U-shaped occipital condyle, the dorsoventral proportions of the posterior braincase and the angle of the exoccipital-supraoccipital contact. Unlike typical ornithopods it displays short and laterally restricted basipterygoids, prominent basal tuberi and a narrow dorsal skull margin. Endocranial features including a very narrow and steep median ridge, the inner ear morphology and the hypoglossal arrangement are more typical of ornithopods. A unique combination of features, most notably: the separate canal for the ophthalmic branch of the trigeminal nerve (CN V), the large fossa above the cerebral carotid foramen, and an almost total absence of a floccular recess, justify an identification as a non-hadrosaurid ornithopod. The presence of various (generally small-sized) ornithopod lineages combined with peculiar morphologies in the Al-Khod vertebrate fauna paradoxically hints at periodic isolation and potentially trans-Tethys faunal connectivity between Afro-Arabia and Eurasia.
The recent transfer of the palaeontological collections of the former Geologisch Museum of Delft ... more The recent transfer of the palaeontological collections of the former Geologisch Museum of Delft University to Naturalis Biodiversity Center (Leiden) has led to the rediscovery of the skull and mandible of the ceratopsian dinosaur Protoceratops. The specimen originates from Campanian aeolian sandstone deposits of the Flaming Cliffs in Mongolia, having been discovered and excavated in 1923 during the Central Asiatic Expeditions. Between 1940 and 1957, it was acquired by Delft University. Most of the right lateral side of the skull and mandible are preserved including the jugal, quadrate, quadratojugal, maxillary (with seven teeth preserved), angular and dentary. Most of the dorsal and the anteriormost part of the skull are not preserved. Several dentary teeth are also present but are largely covered by the maxillary teeth. Additional preparation has revealed several new structures on the posterior and ventral parts of the skull which show remarkable conservation but cannot be determined with certainty because of taphonomic distortion. Based on the size of the skull, the curvature of the dentary, the number of maxillary teeth and the form of the angular depression, the specimen is interpreted as a juvenile P. andrewsi.
Here we report on reconstruction efforts of an incomplete skull of a historically interesting orn... more Here we report on reconstruction efforts of an incomplete skull of a historically interesting ornithischian dinosaur Triceratops from the Lance Formation, near Lightning Creek, Converse County, Wyoming.
The specimen most likely represents the better parts of YPM VP 001832, a skull recovered during the Yale-Hatcher 1891 Cretaceous Expeditions. The majority of the diagnostic elements are absent, overall consisting of most of the skull base, including the majority of the condylar region, sub-orbitals up to the nasal bone anteriorly, and lower jaws.
After collecting, the skull remained in possession of the Yale Peabody Museum up to 1956 before it embarked on its trip to the Delft University Museum in the Netherlands. In return, the Yale Peabody Museum was to receive a collection of fossils from the Dutch colony of Timor. Hampered by illness of the leading staff member of the local museum, damage incurred because of unsuitable conditions during transport, and insufficient reference material, subsequent repair and restoration work on the skull has been inaccurate.
Due to the recent merger of multiple collections into the Dutch national museum, Naturalis Biodiversity Center, new reconstruction efforts are undertaken to restore the specimen. Various sources of information, including locality information, and ontogenetic markers (e.g. dense vascular network, closed frontoparietal fontanelles, parietal thinning, flattened epoccipitals, and number of tooth positions) are employed. By subsequently comparing these to the dimensions and characteristics of known specimens, together with the removal of post-depositional deformation, and the use of 3D-scanning and –printing, a modern approach to reconstruction is undertaken.
A PATHOLOGICAL MOSASAUR SNOUT FROM THE TYPE MAASTRICHTIAN (SE NETHERLANDS)
BASTIAANS, Dylan, ... more A PATHOLOGICAL MOSASAUR SNOUT FROM THE TYPE MAASTRICHTIAN (SE NETHERLANDS)
BASTIAANS, Dylan, Faculty of Geosciences, Utrecht University, Budapestlaan 4, 3584 CD Utrecht, the Netherlands; SCHULP, Anne S., Naturalis Biodiversity Center, Darwinweg 2, 2333 CR Leiden, the Netherlands; JAGT, John W.M., Natuurhistorisch Museum Maastricht, De Bosquetplein 6, 6211KJ Maastricht, the Netherlands
Here we report on the pathologies recognized on a disarticulated mosasaur skeleton from the Maastrichtian (Late Cretaceous) type section, near Maastricht, The Netherlands.
The specimen was discovered in September 2012 by quarry operator Carlo Brauer in the flint-rich Lixhe 3 Member of the Gulpen Formation. The disarticulated assemblage includes partial sections of the maxillae, dentaries, parietal and various elements of the axial skeleton. The skeleton is disarticulated and only partially preserved. Dental morphology suggests affinities with Prognathodon sectorius.
The premaxilla and left maxilla show elongate, healed lesions extending anteroposteriorly, starting near the left premaxillary-maxillary suture, slightly left from the anteroposterior central line. Furthermore, three distinct oblong pits on the left maxilla along with evidence of necrosis and exostiosal bone growth on the tip of the premaxilla are possibly related to smaller gouges located more posteriorly. A less conspicuous callus suggests additional damage to the anteriormost section of the left dentary.
The sheer size of the lesions, the state of bone remodeling, and the advanced degree of healing is most parsimoniously explained by a non-fatal interaction with one (or more) large mosasaur(s).
The lesions observed in this specimen prompted a categorization of pathologies in mosasaurs based on the age, position of the injuries along the skeleton, taxonomic affinities, geological age, and provenance. Lesions are most abundant in the lower jaws, the vertebrae (most often posteriorly in the tail section), and elements of the appendicular skeleton (most often involving the digits).
Conference Presentations by Dylan Bastiaans
EAVP meeting abstract, 2018
The Arabian fossil potential had been largely unexplored until the last two decades. Although its... more The Arabian fossil potential had been largely unexplored until the last two decades. Although its fossil record has improved considerably in terms of quantity, it still largely consists of poorly preserved undiagnostic material. Here we describe a newly discovered enigmatic ornithopod braincase from the Al-Khod Conglomerate Formation of Oman. This formation fills an important spatio-temporal gap, given its position in between Africa and Eurasia, its long palaeogeographic relationship with Africa and being latest Cretaceous (post-Cenomanian) in age. It has produced one of the most taxonomically diverse latest Cretaceous faunas for any Gondwanan landmass and a significant portion of all dinosaur records from the Arabian Peninsula. The braincase is assigned to Ornithopoda on the basis of: a U-shaped occipital condyle, the dorsoventral proportions of the posterior braincase and the angle of the exoccipital-supraoccipital contact. Unlike typical ornithopods it displays short and laterally restricted basipterygoids, prominent basal tuberi and a narrow dorsal skull margin. Endocranial features including a very narrow and steep median ridge, the inner ear morphology and the hypoglossal arrangement are more typical of ornithopods. A unique combination of features, most notably: the separate canal for the ophthalmic branch of the trigeminal nerve (CN V), the large fossa above the cerebral carotid foramen, and an almost total absence of a floccular recess, justify an identification as a non-hadrosaurid ornithopod. The presence of various (generally small-sized) ornithopod lineages combined with peculiar morphologies in the Al-Khod vertebrate fauna paradoxically hints at periodic isolation and potentially trans-Tethys faunal connectivity between Afro-Arabia and Eurasia.
Here we report on a multigenerational assemblage of Triceratops from the Upper Maastrichtian Lanc... more Here we report on a multigenerational assemblage of Triceratops from the Upper Maastrichtian Lance Formation near Newcastle, eastern Wyoming, USA. While fieldwork is still ongoing, in excess of eight hundred elements have already been uncovered, belonging to a minimal number of six individuals. Detailed geological fieldwork at the excavation site shows that the Triceratops skeletons are entombed within an organic-rich clay to siltstone unit characterized by abundant micro-and macro-floral and-vertebrate remains. The Triceratops bones are associated, but also show clear disarticulation. The fifth skeleton is located at the same site, but circa 4 meters above the main bonebed. The site is remarkable since it yields both cranial and post-cranial remains of individuals of different sizes, representing several ontogenetic stages. This assemblage is one of only a handful known sites of the genus Triceratops that contain abundant post-cranial material 4,6. Ontogeny and especially the validity of taxa in Triceratops, and other Chasmosaurinae (e.g. Torosaurus), have been heavily debated subjects 5,9. However, studies have mostly been restricted to descriptions of cranial material due to the scarcity of post-cranial remains 1,2,3,9. Therefore, this assemblage helps to fill in a gap in our knowledge regarding the post-cranial development of these highly derived ceratopsids. This site offers a higher resolution in the ontogenetic development in particularly the late juvenile or early sub-adult to adult stages of Triceratops. By combining histology, allometric measurements, and analysis of morphological characters, the timing of attaining skeletal maturity along with the expression of morphological characters, like suture closure and cranial ornamentation, can be specified. It is evident that individuals in the sub-adult stage reach near-adult size before the closure of most cranial sutures. Additionally, it is recognized that certain post-cranial elements, especially in the pelvic region, experience major remodelling during ontogeny. Future studies with emphasis on intense histological sampling and the use of (µ-)CT scans, will aid in determining the specific timing of these ontogenetic changes.
Drafts by Dylan Bastiaans
• Showing academic thinking capabilities, didactic skills, and research abilities. Demonstrating ... more • Showing academic thinking capabilities, didactic skills, and research abilities. Demonstrating independence, ambition, enthusiasm, preciseness, leadership, and pro-activeness in performing various tasks regarding fieldwork, preparation, research, or education and outreach. • Confident in a vertebrate paleontological lab setting, regarding tool use, rules and regulations, simple repairs, and project-minded approaches. • Thorough background in biology and paleontology, with associated knowledge of geological and medical sciences. Published and presented at international conferences and symposiums, displaying a full working proficiency of both the Dutch and English language.
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Papers by Dylan Bastiaans
The specimen most likely represents the better parts of YPM VP 001832, a skull recovered during the Yale-Hatcher 1891 Cretaceous Expeditions. The majority of the diagnostic elements are absent, overall consisting of most of the skull base, including the majority of the condylar region, sub-orbitals up to the nasal bone anteriorly, and lower jaws.
After collecting, the skull remained in possession of the Yale Peabody Museum up to 1956 before it embarked on its trip to the Delft University Museum in the Netherlands. In return, the Yale Peabody Museum was to receive a collection of fossils from the Dutch colony of Timor. Hampered by illness of the leading staff member of the local museum, damage incurred because of unsuitable conditions during transport, and insufficient reference material, subsequent repair and restoration work on the skull has been inaccurate.
Due to the recent merger of multiple collections into the Dutch national museum, Naturalis Biodiversity Center, new reconstruction efforts are undertaken to restore the specimen. Various sources of information, including locality information, and ontogenetic markers (e.g. dense vascular network, closed frontoparietal fontanelles, parietal thinning, flattened epoccipitals, and number of tooth positions) are employed. By subsequently comparing these to the dimensions and characteristics of known specimens, together with the removal of post-depositional deformation, and the use of 3D-scanning and –printing, a modern approach to reconstruction is undertaken.
BASTIAANS, Dylan, Faculty of Geosciences, Utrecht University, Budapestlaan 4, 3584 CD Utrecht, the Netherlands; SCHULP, Anne S., Naturalis Biodiversity Center, Darwinweg 2, 2333 CR Leiden, the Netherlands; JAGT, John W.M., Natuurhistorisch Museum Maastricht, De Bosquetplein 6, 6211KJ Maastricht, the Netherlands
Here we report on the pathologies recognized on a disarticulated mosasaur skeleton from the Maastrichtian (Late Cretaceous) type section, near Maastricht, The Netherlands.
The specimen was discovered in September 2012 by quarry operator Carlo Brauer in the flint-rich Lixhe 3 Member of the Gulpen Formation. The disarticulated assemblage includes partial sections of the maxillae, dentaries, parietal and various elements of the axial skeleton. The skeleton is disarticulated and only partially preserved. Dental morphology suggests affinities with Prognathodon sectorius.
The premaxilla and left maxilla show elongate, healed lesions extending anteroposteriorly, starting near the left premaxillary-maxillary suture, slightly left from the anteroposterior central line. Furthermore, three distinct oblong pits on the left maxilla along with evidence of necrosis and exostiosal bone growth on the tip of the premaxilla are possibly related to smaller gouges located more posteriorly. A less conspicuous callus suggests additional damage to the anteriormost section of the left dentary.
The sheer size of the lesions, the state of bone remodeling, and the advanced degree of healing is most parsimoniously explained by a non-fatal interaction with one (or more) large mosasaur(s).
The lesions observed in this specimen prompted a categorization of pathologies in mosasaurs based on the age, position of the injuries along the skeleton, taxonomic affinities, geological age, and provenance. Lesions are most abundant in the lower jaws, the vertebrae (most often posteriorly in the tail section), and elements of the appendicular skeleton (most often involving the digits).
Conference Presentations by Dylan Bastiaans
Drafts by Dylan Bastiaans
The specimen most likely represents the better parts of YPM VP 001832, a skull recovered during the Yale-Hatcher 1891 Cretaceous Expeditions. The majority of the diagnostic elements are absent, overall consisting of most of the skull base, including the majority of the condylar region, sub-orbitals up to the nasal bone anteriorly, and lower jaws.
After collecting, the skull remained in possession of the Yale Peabody Museum up to 1956 before it embarked on its trip to the Delft University Museum in the Netherlands. In return, the Yale Peabody Museum was to receive a collection of fossils from the Dutch colony of Timor. Hampered by illness of the leading staff member of the local museum, damage incurred because of unsuitable conditions during transport, and insufficient reference material, subsequent repair and restoration work on the skull has been inaccurate.
Due to the recent merger of multiple collections into the Dutch national museum, Naturalis Biodiversity Center, new reconstruction efforts are undertaken to restore the specimen. Various sources of information, including locality information, and ontogenetic markers (e.g. dense vascular network, closed frontoparietal fontanelles, parietal thinning, flattened epoccipitals, and number of tooth positions) are employed. By subsequently comparing these to the dimensions and characteristics of known specimens, together with the removal of post-depositional deformation, and the use of 3D-scanning and –printing, a modern approach to reconstruction is undertaken.
BASTIAANS, Dylan, Faculty of Geosciences, Utrecht University, Budapestlaan 4, 3584 CD Utrecht, the Netherlands; SCHULP, Anne S., Naturalis Biodiversity Center, Darwinweg 2, 2333 CR Leiden, the Netherlands; JAGT, John W.M., Natuurhistorisch Museum Maastricht, De Bosquetplein 6, 6211KJ Maastricht, the Netherlands
Here we report on the pathologies recognized on a disarticulated mosasaur skeleton from the Maastrichtian (Late Cretaceous) type section, near Maastricht, The Netherlands.
The specimen was discovered in September 2012 by quarry operator Carlo Brauer in the flint-rich Lixhe 3 Member of the Gulpen Formation. The disarticulated assemblage includes partial sections of the maxillae, dentaries, parietal and various elements of the axial skeleton. The skeleton is disarticulated and only partially preserved. Dental morphology suggests affinities with Prognathodon sectorius.
The premaxilla and left maxilla show elongate, healed lesions extending anteroposteriorly, starting near the left premaxillary-maxillary suture, slightly left from the anteroposterior central line. Furthermore, three distinct oblong pits on the left maxilla along with evidence of necrosis and exostiosal bone growth on the tip of the premaxilla are possibly related to smaller gouges located more posteriorly. A less conspicuous callus suggests additional damage to the anteriormost section of the left dentary.
The sheer size of the lesions, the state of bone remodeling, and the advanced degree of healing is most parsimoniously explained by a non-fatal interaction with one (or more) large mosasaur(s).
The lesions observed in this specimen prompted a categorization of pathologies in mosasaurs based on the age, position of the injuries along the skeleton, taxonomic affinities, geological age, and provenance. Lesions are most abundant in the lower jaws, the vertebrae (most often posteriorly in the tail section), and elements of the appendicular skeleton (most often involving the digits).