| Balaenognathus Temporal range: Late Jurassic | |
|---|---|
| |
| Photo of Balaenogathus holotype (under ultraviolet light) | |
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordate |
| Order: | †Pterosauria |
| Suborder: | †Pterodactyloidea |
| Family: | †Ctenochasmatidae |
| Genus: | †Balaenognathus Martill et al., 2023 |
| Type species | |
| †Balaenognathus maeuseri Martill et al., 2023 | |
Balaenognathus (meaning "bowhead whale jaw") is an extinct genus of ctenochasmatoid pterosaur known from the Torleite Formation of Bavaria, Germany. There is currently a single species, B. maeuseri, which is known from the holotype specimen NKMB P2011-633, which consists of a nearly complete and well-articulated skeleton dating to the Kimmeridgian–Tithonian ages of the Late Jurassic.
Discovery[]
Details in the jaws and dentition of Balaenognathus
The holotype specimen of Balaenognathus (NKMB P2011-633) was discovered in plattenkalk limestones near the community of Wattendorf, Bavaria, in southern Germany, in what is known as the the Torleite Formation.
The holotype specimen of Balaenognathus is of an individual preserved on a slab consisting of 17 pieces, which form a well-articulated and nearly complete skeleton dating to the upper Kimmeridgian–Tithonian ages. The specimen preserves hints of soft tissues, including the wing membranes, but is however missing in the left metacarpal distal a distal ‘roller joint, the articular area of a wing-finger phalanx of three fingers, and a small part of the ilium.
The genus, Balaenognathus, and the species, B. maeuseri, where described in 2023 by Martill et al. The generic name "Balaenognathus" is a combination of the generic name of the bowhead whale (Balaena mysticetus), and "gnathus", meaning "jaw" in Latin, while the specific name "maeuseri" was named after the paper's co-author Matthias Mäuser, who unfortunately passed away before the publication of the paper describing Balaenognathus.
Description[]
Comparison of reconstructions of Balaenogathus and other assorted filter-feeding pterosaurs
Tentative line reconstruction of skull and teeth shape and orientation.
Balaenognathus was a long-legged ctenochasmatid pterosaur with a spatula-like beak. It is medium-sized and is estimated to have a wingspan of 1.17 meters, or 3.8 feet.
Classification[]
In 2023, Martill et al found Balaenognathus to be part of the Ctenochasmatidae as the sister taxon to the clade formed by Aurorazhdarcho, Gladocephaloideus, Feilongus, Moganopterus, and Lonchodectes.
Paleobiology[]
Balaenognathus filter-feeding model
A outstanding feature of the specimen of Balaenognathus is the unusual dentation of the pterosaur, which is thought to have aided it in the filter-feeding lifestyle that has been proposed for it. The jaws had a total of at least 480 sub-parallel-sided teeth with small hooks near the crown tips, spatula-like concave structures on the tip of the rostrum which included teeth only in lateral margins, and with an absence of teeth in the straight anterior margin, which is speculated to have let water carrying plankton into the mouth while the unusual teeth interdigitated to form a trap for the plankton. The specimen also preserves a slightly raised rostrum, which could have helped Balaenognathus in filter-feeding by pulsating its neck while wading or swimming through swallow water.
Paleoenvironment[]
Balaenognathus lived in the Torleite Formation, a geologic formation and Lagerstätte in Germany. Vertebrate fauna it lived alongside included the crocodylomorphs Alligatorium franconicum, Cricosaurus bambergensis, Dakosaurus maximus, the dinosaur Sciurumimus albersdoerferi, the turtle Eurysternum wagleri, the rhynchocephalian Sphenofontis velserae, and the fish Anaethalion, Leptolepides, Leptolepis, Pholidophorus, and Pleuropholis.