First bird footprints from the lower Miocene Lerín Formation, Ebro Basin, Spain

Abstract

A new tracksite with bird footprints, found in the Bardenas Reales de Navarra Natural Park (Navarre, Spain), is presented in this study. The footprints are preserved in four sandstone blocks of the Lerín Formation from the northwest sector of the Ebro Basin. According to the magnetostratigraphic data, the age of these blocks is 20.4 Ma (Agenian, lower Miocene). The footprints are more than 100 mm in length, mesaxonic, and tridactyl, and have a prominent central pad impression with the digit impressions not jointed proximally. These features allow classifying them as Uvaichnites riojana. Some of the studied footprints are better preserved than the type series of Uvaichnites, which were found also in the northwest sector of the Ebro Basin. Therefore, the original diagnosis has been emended. Available chronostratigraphic data for these localities as well as for other footprints from China indicate a latest Oligocene-earliest Miocene age (from about 23 to 20 Ma) for Uvaichnites-like footprints. Sedimentological data also indicate similar continental environments, namely perilacustrine deltaic systems and distal alluvial systems. The information about early Miocene avian remains (bones, eggs and footprints) in the Iberian Peninsula is scarce. The skeletal and oological record of this age has been included within the families Phoenicopteridae, Phaisanidae and Cathartidae (or incertae sedis), while the ichnological record was related with trackmakers belonging to Charadriiformes, Ardeidae and Gruidae taxa. For this scenario, in which there are few avian remains, the ichnological diversity shown in this paper complements and improves the knowledge about the Iberian avian diversity in the early Miocene.

Re-evaluation ofChelichnus tazelwürmi,a non mammalian therapsid-grade track from the Upper Permian Arenaria di Val Gardena

“…This method is based on Structure from Motion (Ullman 1979) and Multi View Stereo (Seitz et al 2006) algorithms and produces high quality dense point clouds. Different software solutions exist for Digital Photogrammetry (see Wu 2007Wu , 2011Falkingham 2012;Cipriani et al 2016), which in the recent past was largely adopted in the field of Palaeontology and Earth Sciences in general (Breithaupt et al 2004;Petti et al 2008;Citton et al 2015Citton et al , 2016Citton et al , 2017De Beni et al 2015;Lockley et al 2015;Díaz Martínez et al 2016, 2017Fabbi et al 2016;Lomax et al 2017;Romano et al 2017) The software package for Digital Photogrammetry chose to model MPUR N.S. 34/28 is Agisoft PhotoScan Pro (http://www.agisoft.com), which enables creating 3D textured meshes by means of semi-automatic processing of images (Mallison and Wings 2014).…”

Defining the morphological quality of fossil footprints. Problems and principles of preservation in tetrapod ichnology with examples from the Palaeozoic to the present

“…M-preservation. These tracks were classified as Uvaichnites riojana according to their main ichnotaxobases (see Díaz-Martínez et al, 2016) recorded in the footprints with the best morphological preservation (grade 2.0-2.5). They are better preserved than the type series, so the diagnosis was emended and converted to a more complete and robust definition.…”

Multi-aged social behaviour based on artiodactyl tracks in an early Miocene palustrine wetland (Ebro Basin, Spain)

“…In the last 20 years, different studies in the northwestern part of the continental Ebro Basin (Fig. 1) have reported a wealth of novel Cenozoic (Eocene to Miocene) palaeoichnological data 40 .…”