Gastornis laurenti sp. nov. (1 Viewer)

[Fred Ruhe]

Cécile Mourer-Chauviré & Estelle Bourdon, 2020

Description of a new species of Gastornis (Aves, Gastornithiformes) from the early Eocene of La Borie, southwestern France

Geobios. in press.
doi:10.1016/j.geobios.2020.10.002

Abstract: https://www.sciencedirect.com/science/article/abs/pii/S0016699520300863

The Early Eocene locality of La Borie is located near the village of Saint-Papoul, in southwestern France. It consists of clay deposits that have yielded numerous vertebrate fossils, including remains of the giant flightless bird Gastornis. These remains were initially attributed to the species G. parisiensis, which is otherwise recorded from the late Paleocene and earliest Eocene of the North Sea Basin. New fossil birds collected in the La Borie clay pit in 2018 include an almost complete mandible of Gastornis. We describe a new species of Gastornis based on this mandible and we show that the previously described remains from La Borie must be assigned to this new species. The new species differs from other species of Gastornis in the morphology of the mandible, maxilla and quadrate. The morphological diversity of the genus Gastornis, which existed in Europe for at least 17 million years, is emphasized.

LSID of publication: urn:lsid:zoobank.orgub:10E7938B-C972-4127-94DC-169D35977B11

The new species is Gastornis laurenti sp. nov.

Enjoy,

Fred

 

[Fred Ruhe]

Systematic palaeontology

Class Aves Linnaeus, 1758
Order Gastornithiformes Stejneger, 1885
Family Gastornithidae Fürbringer, 1888
Genus Gastornis Hébert, 1855
Type species: Gastornis parisiensis Hébert, 1855 (« Conglomérat de Meudon », Ypresian, early Eocene, Meudon, Hauts-de-Seine, France).
Gastornis laurenti nov. sp.
LSID of new species: urn:lsid:zoobank.org:act:BAD679B2-1808-4512-B1FF-F9A136B32454

Holotype: MHNT.PAL.2018.20.1, almost complete mandible found in SP2.

Paratypes: MDE-A18, left tibiotarsus (Buffetaut, 2008, unknown SP); APSO.2006.SP1-62, right tibiotarsus; MHNT.PAL.2013.15.1, maxilla (SP5); MHNT.PAL.2013.15.2, right quadrate (SP5); MHNT.PAL.2013.15.3 to 8, six cervical vertebrae (SP1 and SP2); MHNT.PAL.2013.15.9, shaft of a left femur (SP2); MHNT.PAL.2013.15.10, left tibiotarsus (SP5) (Bourdon et al., 2016); all these bones are from the type locality.

Derivation of the name: This species is dedicated to Yves Laurent, who directed the excavations in the quarry of La Borie from 2006 onwards, and discovered the mandible.

Type locality: La Borie, Saint-Papoul, Department of Aude, southern France.

Type horizon: Middle Ypresian, early Eocene, close to reference level MP 8-9, age ca. 52-53 Ma (Danilo et al., 2013).

Referred material: The material also includes a series of postcranial gastornithid bones, partly from the same individual, which will be described in a subsequent publication.

Diagnosis: Mandibula: very elongate symphysis mandibulae; ventral outline of rostrum mandibulae strongly oriented craniodorsally (horizontal in G. parisiensis and slightly oriented craniodorsally in G. giganteus); canaliculi neurovasculares scarce and shallow (numerous and deep in the other species of Gastornis); internal surface of rostrum mandibulae smooth (presence of an inner ledge in G. giganteus); caudal edge of symphysis more rounded than in other species; articular part narrower than in other species; line linking the middle of the processus lateralis and medialis almost perpendicular to the long axis of the ramus mandibulae (obliquely oriented in G. giganteus); absence of crista intercotylaris between cotyla lateralis and cotyla medialis (crista intercotylaris present in G. parisiensis and G. giganteus). Os quadratum: tuberculum musculi adductor mandibulae oval in shape (prominent and hooked ventrally in G. parisiensis; large and rounded in G. giganteus); processus mandibularis lateromedially narrow (wider and shorter in G. parisiensis and G. giganteus); shallow sulcus intercotylaris (deeper in G. parisiensis and G. giganteus); shallow cotyla quadratojugalis, as in G. giganteus (deep, circular and surrounded by a thick ridge in G. parisiensis); slender processus orbitalis (very stout in G. giganteus). Maxilla: large apertura nasi ossea (smaller in G. giganteus and G. geiselensis); apertura nasi ossea more ventrally located than in G. giganteus; shallow sulcus nasi (deeper in G. giganteus); maxilla shorter than in G. giganteus; nasolacrimal process tall and prominent laterally (small and poorly developed in G. giganteus).

Fred

Fig. 1. Gastornis laurenti nov. sp., holotype mandible MHNT.PAL.2018.20.1 in dorsal (A), ventral (B) and caudal (C) views. Abbreviations: cc, crista coronoidea; cl, cotyla lateralis; cm, cotyla medialis; cn, canaliculi neurovasculares; cto, crista tomialis; fn, foramina neurovascularia; mg, insertion of musculus genioglossus; pc, processus coronoideus; pf, pneumatic foramen; pl, processus lateralis; pm, processus medialis; pr, processus retroarticularis; sm, symphysis mandibulae; tc, tear-shaped concavity. Scale bars: 2 cm.

Fig. 2. Gastornis laurenti nov. sp., holotype mandible MHNT.PAL.2018.20.1 in left dorsolateral (A), caudal (B) and dorsal (C) views. Abbreviations: cc, crista coronoidea; cl, cotyla lateralis; cm, cotyla medialis; ctr, crista transversa; fc, fossa caudalis; pc, processus coronoideus; pf, pneumatic foramen; pl, processus lateralis; pm, processus medialis; pr, processus retroarticularis; tc, tear-shaped concavity. Scale bars: 2 cm.

Fig. 3. Gastornis parisiensis Hébert, 1855, mandible MHNT.PAL.2012.1.1 in ventral (A), dorsal (B), right lateral (C) and left lateral (D) views. Abbreviations: ci, crista intercotylaris; cl, cotyla lateralis; cm, cotyla medialis; cn, canaliculi neurovasculares; fn, foramina neurovascularia; pc, processus coronoideus; pf, pneumatic foramen; pl, processus lateralis; pm, processus medialis; sm, symphysis mandibulae; tc, tear-shaped concavity. Scale bars: 2 cm.

Fig. 4. Gastornis giganteus (Cope, 1876), mandible AMNH 6169 in ventral (A) and dorsal (B) views. Abbreviations: ci, crista intercotylaris; cl, cotyla lateralis; cm, cotyla medialis; cto, crista tomialis; pc, processus coronoideus; pl, processus lateralis; pm, processus medialis; pr, processus retroarticularis; sm, symphysis mandibulae; tc, tear-shaped concavity. Scale bar: 2 cm.