Export permits

Please note an export permit must be linked to an object or site that has to be created on SAHRIS! If the object/site you want to work on has not been created yet, you would need to do so. Thanks!

The proposal should include (you can fill these in below): - a list of participants (name, affiliation, phone no, email addresses) and how they are involved; - the name and address of the facility, including address, it is being scanned at; - name and address of the museum/university department that currently hosts the object; - names of the responsible person(s) during transport and while the fossil is at the facility; - the period/time frame during which the fossil(s) will be outside the country; - detailed information on the fossil(s), especially as it is a "unique" specimen; - detailed information on the research project behind it & methodology including expected outcomes (i.e., the reason for export); - the written confirmation of the institution that currently hosts the object that the object may be used as proposed and be returned in good condition; - should there be any damage/destructive analysis (e.g., coating for higher resolution) undertaken, this needs to be stated in detail; - Statement why this study cannot be done in South Africa.

Applicant (name and affiliation): Dr. Julien Benoit

Participants with affiliations, email addresses, phone numbers (& their role): 1) Dr. Julien Benoit Role: will be in charge of the transport and scanning of the fossil 2) Dr. Vincent Fernandez Role: will scan the fossil along with JB 3) Dr. Paul Tafforeau Role: will scan the fossil along with JB

The material will be hand-carried to the European Synchrotron Radiation Facility (Grenoble France) in September 2017 by Julien Benoit and brought back by ______(leave blank if same person as above). Julien Benoit will be involved with the transport and scanning of objects and Dr. Vincent Fernandez and Dr. Paul Tafforeau will assist for the scanning only. The scanning will be performed on the 27, 28 and 29 of October 2017.

Institution incl. address that currently hosts the objects: University of the Witwatersrand, Evolutionary Studies Institute, PO Wits 2050, Johannesburg

Facility incl. address at which the experiment will be done: European Synchrotron Radiation Facility 71 Avenue des Martyrs, 38000 Grenoble, France Table of objects or upload file: Tritylodon longaevus (x2) (Probainognathia, Tritylodontidae): BP/1/5088 (L: 15cm; w: 6cm; h=4cm) and BP/1/4778 (L: 16cm, w: 7cm; h: 4cm) Pachygenelus sp. (Probainognathia, Trithelodontidae) : BP/1/5691 (L=4cm; w=2cm; h=1,5cm) Pachygenelus monus (Probainognathia, Trithelodontidae) : BP/1/5110 (L=3,5cm; w=2cm; h=1,7cm) Lumkuia fuzzi (Probainognathia, non-Prozostrodontia) : BP/1/2669 (L: 5cm; w: 3cm; h: 2cm) Megazostrodon sp. (Probainognathia, Mammaliaform) : BP/1/4983 (L: 5cm; w: 3cm; h: 1cm) Mammaliformes Indet.: BM-17-3L (the oversized block will be prepared for scanning) In addition to these specimens, the snout of the biarmosuchian SAM-PK-11112 (Iziko Museum; Cape Town, South Africa; L: 149mm; w: 130mm; h: 112mm), as one of the basal-most therapsid, will be scanned for outgroup comparison.

Time frame: Transport to ESRF: 25 October 2017 (date) Return date: 02 November 2017 (date)

Aim/rationale: The evolution of non-mammalian therapsids (mammal-like reptiles, the ancestors of extant mammals) from the Permian and Triassic was marked by numerous adaptation to a wide variety of ecological niches, from tiny to large herbivorous species and from small insectivores to super- predators. These adaptations required specialized facial sensitivity. More particularly, adaptation to nocturnality and the evolution of whiskers at the transition from basal therapsids to early mammaliaforms has dramatically changed the way the environment was perceived by our ancestors.

Whiskers (vibrissae) are facial stiff and tactile hair that play a critical role in sensing the environment in mammals. Along with a highly sensitive hearing, the evolution of whiskers and whisking movements is a key adaptation that helped mammals to conquer the nocturnal niche during the Mesozoic era and certainly played a critical role in their survival during the dominance of dinosaurs. In most therapsids, the trigeminal nerve, which is responsible for the innervation of whiskers and facial sensitivity, is encapsulated in a bony canal, the maxillary canal. The evolutionary transition from a complete maxillary canal to a retracted mammalian infrorbital foramen is correlated to the evolution of a motile snout and whisking movements in derived therapsids and mammals. However, if it appears likely that this important transition occurred in a group of derived therapsids called the Probainognathia, many questions remain unsolved. How this morphological transition occurred? Was it gradual or abrupt? Which species or group of species were concerned? When did it occur? Is there a correlation with the evolution of small size in early mammaliaforms? How precisely does this transition relate to the evolution of nocturnality? This project aims to answer these questions.

Here, using high precision synchrotron scanning, it is aimed to observe the fine structures of the maxillary canal in a variety of key species of therapsids in order to reconstruct the evolution of their trigeminal nerve, the nerve responsible for the sensitivity of the face. This will refine knowledge of the evolution of whiskers in the lineage leading to mammals. This project will reshape our understanding of the evolution of “Mammalness” in our therapsids ancestors and sheds new light on specific major steps in the evolution of mammals such as facial sensitivity, whiskers and their associated traits such as fur coverage, associated glands (including mammary glands), and endothermy (‘warm-bloodedness’).

Methodology (short): The specimens will be characterized using propagation phase contrast microtomography using filtered pink beam from a wiggler aiming for a detected energy of 100 keV, and long propagation distance (adapted to energy and recorded pixel size). To image the full skull, we will use 12.5 µm for the smaller specimens, 22 µm for the largest ones (both achievable with PCO.edge 5.5 and hasselblad lenses based optical system). The region occupied by the trigeminal nerve from the braincase to the nerve will be scanned at higher resolution to ensure proper visualisation of the smallest branches of the canals (typically 3.5 µm). This procedure represents no risk for the fossils.

Confirmation/permit by museums: see attachment

Damage/destructive analysis? (if yes, explain in detail) NO

Statement why this study cannot be done in South Africa: We need high precision synchrotron scanning for two reasons: i) The density of the matrix and frequent presence of iron nodules in many South African fossils hinders high quality images when applying conventional µCT, ii) The maxillary canal for the trigeminal nerve is a small osseous tube running through the maxilla that is nearly invisible on standard µCT scans. In addition, many of our specimens are rather small which make the observation of their maxillary canal more difficult. Voxel size inferior to 5µm would be required, which is impossible to achieve on such fossils with a standard µCT scan with equipment available in South Africa. Synchrotron scanning also involves monochromatic radiation which considerably reduces the artifacts that might make the data unusable if acquired on a regular µCT scan. The ID19 beamline of the ESRF offers all the requirements to achieve our goals. Additionally, the knowledge of local scientists will be important to limit the effect of the dense metallic inclusions in the reconstructed data, using newly developed algorithms. Specimens SAM-PK-11112 and and BP/1/4983 have already been scanned at synchrotron, however, the specific requirements for this project prevent the use of previous data and thus, new scans have to be performed.