De Amsterdamse collectie fossielen uit de Grot van Ultima Esperanza (Patagonië, Zuid-Chili)

In 1908-1909 Jan Herman Kruimel, a zoologist at the Zoological Museum of Amsterdam University (The Netherlands) (ZMA), made an expedition to the south of Chili to collect zoological materials for Professor Dr. Max Weber in Amsterdam. Along with modern biological material, Kruimel made an extensive collection of Pleistocene mammal remains from Ultima Esperanza Cave in Patagonia. At this time, the Ultima Esperanza Cave was already well-known for its remains (bones, skin and excrements in a wonderful state of preservation) of the ground sloth, Mylodon darwinii OWEN, 1840. The recovery of well preserved soft tissue from the cave resulted in much debate about the extinction of the animal, both in the scientific community and the media. Numerous collections were made from the cave and then sold to different museums, including the British Museum of Natural History in London, England. Unfortunately Kruimel's notes do not indicate if he actually visited the cave himself. According to a letter written from Kruimel to his brother in the Netherlands, he obtained the collection of bones, teeth and skin of the Mylodon in 1909 from H. Hansen and C.A. Milward, both who had previously sold collections from the cave to the British Museum.The Kruimel Collection in the Zoological Museum consists of 202 catalogued specimens and a large number of uncatalogued vertebrae of Darwin's ground sloth. We have summarized the collection according to the catalogue. The preliminary identifications were made in 1909-1910. Mylodon darwinii (94 specimens), Neomylodon listai = Mylodon darwinii (1 specimen), Felidae (40 specimens), Felis concolor(5 specimens), Smilodon ensenadensis (16 specimens), Smilodon neogaeus (skull, plaster), Equus argentinus (1 specimen), Equus curvidens (1 specimen), Onohippidion saldiasi (2 specimens),Lama huanachus (35 specimens), Lama guanicoe (5 specimens), Propalaeohop (1 specimen) and one, unnumbered glass bell with almost complete excrements of Mylodon darwinii. One of the best and most interesting specimens in the Kruimel Collection is a piece of skin of Mylodon which is figured and briefly described in this paper for the first time.From a locality at Rio Verde, 75 km north of Punta Arenas, Kruimel collected 4 upper molars of a horse, Equus argentinus Burmeister.The Amsterdam collection from the Ultima Esperanza is unknown in the scientific community. In all reviews on the Late Pleistocene fauna of Ultima Esperanza, the collection made by Kruimel has not been mentioned, although the materials brought back to Amsterdam by Kruimel was identified with the help of Dr. Smith-Woodward in London. Although he had started to study the collection, Kruimel never completed the publication before his death. The only mention of the collection is a short printed anonymus report in Dutch on a meeting of the 'Nederlandsche Dierkundige Vereniging' (Anoniem, 1913) which notes that Kruimel gave a lecture on September 25, 1910, where he stated that the sabre-toothed cat in his collection from Ultima Esperanza is of great scientific interest because this species was never reported before south of Buenos Ayres.In this paper we report about the Ultima Esperanza Cave and its history and the Kruimel Collection in the Zoological Museum in Amsterdam. Some notes are given on Darwin's ground sloth, Mylodon darwinii, which is the dominate member of the Late Pleistocene fauna of Ultima Esperanza around 13,560 and 10,200 yBP. All notes and correspondence made by Kruimel during and after his expedition have been studied by us and the results are presented here.