caa a22 4500 477136699 CHVBK 20180405111720.0 cr unu---uuuuu 170330e19970301xx s 000 0 eng 10.1023/A:1027300726126 doi (NATIONALLICENCE)springer-10.1023/A:1027300726126 Martin Thomas Institut für Paläontologie, Freie Universität Berlin, Malteserstrasse 74-100, D-12249, Berlin, Germany aut Tooth Replacement in Late Jurassic Dryolestidae (Eupantotheria, Mammalia) [Elektronische Daten] [Thomas Martin] The discovery of juvenile dentitions of late Jurassic (Kimmeridgian) Dryolestidae (Eupantotheria, Mammalia) from Guimarota, Portugal, yields for the first time information on the mode of tooth replacement in therian mammals prior to the dichotomy of placentals and marsupials. As in extant placentals, tooth replacement occurs at all antemolar positions [incisors (I1-I4), canine (C), premolars (P1-P4)]. P1 and P2 have premolariform milk predecessors, whereas the large premolariform third (P3) and fourth premolars (P4) are preceded by molariform deciduous premolars (dP3, dP4). Tooth replacement takes place in two waves, at least in the lower jaw, with I2, I4, P1, and P3 in the first series and I1, I3, C, P2, and P4 in the second. P4 is the last premolar to erupt, and it is present when the sixth molar (M6) starts to break through. The reduced tooth replacement pattern of marsupials (with only dP3 being replaced postnatally) evolved secondarily from the primitive or plesiomorphic mammalian condition, which was retained in Dryolestidae and Eutheria. Plenum Publishing Corporation, 1997 Dryolestidae nationallicence Eupantotheria nationallicence Jurassic nationallicence deciduous teeth nationallicence tooth replacement nationallicence Journal of Mammalian Evolution Kluwer Academic Publishers-Plenum Publishers 4/1(1997-03-01), 1-18 1064-7554 4:1<1 1997 4 10914 https://doi.org/10.1023/A:1027300726126 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1023/A:1027300726126 text/html Onlinezugriff via DOI NATIONALLICENCE 100 1- Martin Thomas Institut für Paläontologie, Freie Universität Berlin, Malteserstrasse 74-100, D-12249, Berlin, Germany aut NATIONALLICENCE 773 0- Journal of Mammalian Evolution Kluwer Academic Publishers-Plenum Publishers 4/1(1997-03-01), 1-18 1064-7554 4:1<1 1997 4 10914 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer