New Paleocene bird fossils from the North Sea Basin in Belgium and France

Abstract

We describe new avian remains from Paleocene localities of Belgium and France. Four bones from the early to middle Selandian of Maret (Belgium) are among the earliest Cenozoic avian remains known from Europe and include the oldest temporally well constrained European records of the Gastornithidae, as well as tentative records of the palaeognathous Lithornithidae and the Ralloidea. A more comprehensive fossil assemblage from the middle Thanetian of Templeuve (France) contains multiple bones of the Lithornithidae as well as a record of the Pelagornithidae. Specimens from the latest Thanetian of Rivecourt-Petit Pâtis (France) are tentatively assigned to the Ralloidea and Leptosomiformes (cf. Plesiocathartes). Because of the fragmentary nature of the fossils, the taxonomic identity of a number of other specimens remains uncertain. We note, however, that Paleocene avifaunas of Europe and North America appear to have had different compositions and only a few taxa, such as the palaeognathous Lithornithidae, are known from both continents. This suggests that the very similar early Eocene avifaunas of Europe and North America are the result of early Cenozoic dispersal events.

New Material of Paleocene-Eocene Pellornis (Aves: Gruiformes) Clarifies the Pattern and Timing of the Extant Gruiform Radiation

“…Conflicting with this temporal scenario, however, many Paleogene ralloid-like fossils have been recovered from Europe, suggesting that crown Gruiformes may have diverged earlier in the Cenozoic [19,20] and citations therein. This includes a ralloid-like, fragmentary distal tarsometatarsus from Belgium and a ralloid-like right coracoid from France that date to the Paleocene [21]. Problematically, the precise affinities of many such fossils remain questionable as they are fragmentary and/or poorly preserved [22,23].…”

Higher level taxonomy affects body mass and femur length as predictors for egg size in birds

“…The predicted femur length was 282 mm, which was comparable to other femurs attributed to D. C. Deeming Gastornis (Gastornithidae). However, using the phylogenetically controlled relationship reported here for all eggs, a femur attributed to Gastornis geiselensis measuring 333 mm (Mayr & Smith 2019) would have a predicted egg mass of 738 g and the range of egg mass of 630-760 g is predicted for other Gastornis femurs measuring between 300-340 mm (Angst et al 2014). These estimates are around half the predicted egg mass of 1400 g based on estimated dimensions (Angst et al 2014), which rather undermines the use of egg mass to calculate femur length.…”

The Evolution and Fossil Record of Palaeognathous Birds (Neornithes: Palaeognathae)

“…The fossil record of lithornithids in Europe also begins in the middle Paleocene, and stretches to the middle Eocene (Figure 7, Table 1) [96,111,112]. The Orp Sand member (early to middle Selandian) of the Heers Formation in Maret, Belgium yielded a distal humerus fragment and a partial carpometacarpus that were assigned to Lithornithidae, but the fossils are too incomplete to be assigned at a generic level [96].…”

“…The fossil record of lithornithids in Europe also begins in the middle Paleocene, and stretches to the middle Eocene (Figure 7, Table 1) [96,111,112]. The Orp Sand member (early to middle Selandian) of the Heers Formation in Maret, Belgium yielded a distal humerus fragment and a partial carpometacarpus that were assigned to Lithornithidae, but the fossils are too incomplete to be assigned at a generic level [96]. The next oldest European lithornithid, Fissuravis weigelti, is also known from fragmentary remains, in this case the omal end of an isolated coracoid from the late middle Paleocene (Selandian) of the fissure filling of Walbeck, Germany [98].…”