For the Museum of Zoology and Comparative Anatomy in 2018 and 2019 – i.e. in the two years preceding the pandemic and the subsequent closure of the museum in 2020 – a conservation plan was implemented. In addition to environmental monitoring of the historic rooms by Riccardo Balzarotti’s Servizi Museali, which produced satisfactory results in terms of temperature and relative humidity levels, the inventory was also checked and the exhibits were renumbered and assigned to the Polo Museale.
The computerised cataloguing of the specimens has also been started, continuing the experimentation already begun by the University Museums Network and using the layout of the BNZ card for zoological assets as part of SIGECweb, the web-based Catalogue Information System, in collaboration with the ICCD, the Central Institute for Catalogue and Documentation of the Ministry of Culture.
The monitoring of the Museum’s specimens also entailed checking the state of conservation of the exhibits, which was noted in the inventory so that it could later be reported on the conservation card that will be created for each specimen. This monitoring has made it possible to draw up a list of specimens with priority needs for maintenance and restoration work.
The black rhinoceros Diceros bicornis
The decision to carry out the first restoration work on a specimen of black rhinoceros (Diceros bicornis Linnaeus, 1758), located in the central Spallanzani room of the Museum, was determined not only by conservation requirements, but also by its rarity, since it seems to be the only complete specimen traceable in Italy and probably in Europe. Because of its aggressive temperament, the black rhinoceros is considered one of the most dangerous animals together with the hippopotamus.
There are currently three subspecies of black rhino as a fourth, Diceros bicornis longipes, is now considered extinct in its last known habitat in northern Cameroon. The other three most numerous subspecies are found in eastern and southern Africa: Diceros bicornis minor was once widespread from central Tanzania, through Zambia, Zimbabwe and Mozambique, to northern and eastern South Africa (the most numerous subspecies); Diceros bicornis bicornis is a subspecies of the arid and semi-arid savannas of Namibia, southern Angola, western South Africa and western Botswana; Diceros bicornis michaeli was found in most of the savannas of western Africa, from South Sudan to Tanzania.
According to the International Union for Conservation of Nature – IUCN Red List, the largest database of information on the conservation status of animal and plant species around the globe, the black rhinoceros is considered ‘critically endangered’.
Its current distribution is classified as: Native, extant (resident): Angola; Kenya; Mozambique; Namibia; South Africa; Tanzania, United Republic of; Zimbabwe. Native, extinct: Benin; Burkina Faso; Cameroon; Central African Republic; Chad; Congo; Eritrea; Ethiopia; Niger; Nigeria; Somalia; South Sudan; Sudan; Togo; Uganda. Existing and reintroduced (resident): Botswana; Eswatini; Malawi; Rwanda; Zambia. Rhinos are mainly threatened by illegal poaching of their horns.
The black rhinoceros in the Zoological Museum of Modena is a young fully taxidermied female, Diceros bicornis as the historical tag reads, most likely belonging to the subspecies michaeli. It comes from Somalia, where it is currently extinct: the black rhinoceros was donated as a skin to the Zoological Museum in 1933 by Guido Corni, a Modenese who was governor of Somalia from 1928 to 1931. Corni also donated several other vertebrates to the Zoological Museum, mostly hunting trophies from the Somali period, including a rhinoceros, a hippopotamus, two lions, a young oryx, an antelope, an ostrich, a crocodile and a sea turtle shield. For their considerable size, the animals were sent ‘in their skins’ and prepared in Modena for the exhibition. In fact, also in 1933, Ferruccio Luppi, the Museum’s taxidermist, mounted the black rhinoceros skin on a wooden mannequin in natural pose, according to the taxidermy techniques of the time. It is not clear whether the rhinoceros and the hunting trophies were sent from Somalia after Corni’s return to Modena, since in one Museum register they appear all together as a “Corni gift” without a date and in another with the date 02.01.1933.
Restoration work
The intervention was preceded by a careful autopsy examination of the state of preservation, which was carefully documented: the rhinoceros showed deformations and shrinkage on the surface of the skin with various fractures, partial cracks and localised structural failures due to natural drying. Samples of the stucco and padding of the rhinoceros were taken. Numerous skin lesions were also present in the ventral area (including the neck), distal to the limbs and at the nail attachments. In addition, the plaster used for the fillings, which is typically hygroscopic, was severely cracked and detached in large areas, particularly in the posterior portion of the preparation. The right ear was severely damaged; the two horns, anchored with iron nails, were structurally unstable.
The wooden base, which had been painted subsequently and stained the rhinoceros, had deteriorated with various spots caused by humidity, cracks and detachment of the paint.
The restoration work, carried out by Oreste Sacchi, Ugo Ziliani and Salvatore Restivo of Platypus, under the supervision of Roberto Monaco, an official of the Bologna Soprintendenza Archeologia Belle Arti e Paesaggio, and Cristina Ambrosini, superintendent, was non-invasive and involved the use of non-polluting substances.
Inconsistent deposits were removed using a dry vacuum cleaner and soft-bristled brushes; sediments were removed using nylon brushes, scalpels, pliers and mirrors. Prior to cleaning, tests were carried out using localised compresses with Arbocell 200 and demineralised water to assess how to carry out effective, non-invasive cleaning. The surface was then cleaned using natural sponges moistened with demineralised water and a neutral non-ionic surfactant derived from ethylene oxide (tween20 in 2% demineralised water). Subsequently, the horn was blocked with iron pins to provide structural stability, and localised fixation of the skin fragments partially detached from the wooden support was carried out using an aqueous dispersion of acetovinyl homopolymer (Vinavil) at various dilutions, applied by brush and syringe.
Biodeteriogenic microorganisms were inhibited by brush application of a mixture of demineralised water and 2% benzalkonium chloride. The reconstruction of lacunae and small to medium-sized cracks was carried out by level filling with a compound based on acetovinyl homopolymer, phyllite microspheres and cellulose fibres, applied with a spatula and modelled with small spatulas and pins, taking care to reconstruct the texture of the skin. In particular, careful reconstructive work was carried out on the base of the horn and the right ear, a large portion of which was completely detached.
After thorough washing with demineralised water and 2% Tween 20, the non-original layer of loose and exfoliated paint covering the base was removed. The large cracks in the base were filled to a level and the base was repainted with a water-based white paint similar to the original.
The start of the spread of the pandemic at the beginning of 2020 prevented the organisation of an open restoration workshop to allow the public to witness the various stages of the work in the museum.
