État des recherchessur la faune de Mammifères du Montien de Hainin (Belgique)

Abstract

The search for a european Paleocene mammal fauna older than the Thanetian has been a long one… The discovery at last of a few micromammal teeth in continental Montian was made almost by chance when I. Godfriaux of the Mons School of Mines asked me for identification of bone scraps recovered from a small-diameter boring conducted by him in 1970 in the type area of the Montian at Hainin. The country beeing flat and low, even artificial outcrops are rare and incomplete, so the boring was necessary for a better knowledge of the stage. Despite the unusual setting for a mammal quarry (at a depth between 10 and 25 m, in unconsolidated sediments below the water table) this discovery prompted us to apply for à Fonds National de la Recherche Scientifique grant. Thanks to this enlightened Belgian institution I. Godfriaux was able to open in 1973 a conventional pit, earth-proofed by a steel pipe, equipped with a water-pump and wide enough for a little man to shovel at the bottom. A bad accident interrupted the excavation for months but it was resumed and ended in 1974. The concentration in mammal remains proved tobe variable but never high nor nil, so we had to wash and sieve all of the sediments below marine Landenian. Most of the teeth beeing very small we used a 0,43 mm mesh! All the matrix has been pretreated at Mons and the residue has been sent to Montpellier where it is in the process of beeing re-washed-and-sieved and sorted. At the present rate we will not be through before years! The material presently sorted ranges from 11 m to 17 m depth and comprises 91 mammals fragments which are entire or incomplete isolated teeth and a very few bones. Lower vertebrate remains, mainly fish teeth and scales, are much more abundant. The biggest mammal is a multituberculate, seemingly referable to Catopsalis. Let us note incidentally that this genus is unknown in North America later than Puercan times. Most mmamals are very small tribosphenic eutherians. Among them are nyctitheres, adapisoricids, erinaceomorphs, apatemyids and possibly miacids (or paroxyclaenids). There are a few small bunodonts; one of them approaches Louisina and Microhyus, a group of condylarths endemic to Europe. Metatherians are problematic. On geological grounds this fauna is Montian, that is to say older than Thanetian. On paleontological grounds the provisional impression is of an older age than the classical Upper Paleocene faunas of North America and Europe (French Thanetian and Walbeck). As expected this fauna exhibits North American affinities but also a moderate degree of endemicity. The study of animal and plant fossils from Hainin will be conducted on an international cooperative basis under the supervision of I. Godfriaux, the work of mammalogists beeing organised from now on by B. Sigé.