Batrachognathus volans (Rjabinin 1948) Oxfordian/Kimmeridgian, Late Jurassic ~155 mya, 10 cm snout-to-vent length, [PIN 13] was the second anurognathid described but, again, no skull or skeletal reconstructions were attempted. Derived from a sister to the CAGS specimen of Jeholopterus, Batrachognathus was a sister to the IVPP specimen of Jeholopterus and both represent the last of the dimorphodontoids.
A second anurognathid previously assigned to Batrachognathus (Bakhurina 1988, PIN 2585/4) was found on the same slab as Sordes, the only slab that contains two different pterosaurs. The PIN 2585/4 specimen is actually a long-legged sister to the CAGS specimen and is the only known flightless anurognathid pterosaur.
Distinct from the CAGS specimen of Jeholopterus, the skull of Batrachognathus was taller. The nasals were narrower and the frontals more triangular, which rotated the orbits tothe anterior, approximately at right angles to each other. Like the holotype of Jeholopterus, this gave Batrachognathus stereoscopic vision. The teeth were small, homodont and curved posteriorly. The quadrate was vertical. The ectopalatine and pterygoid were robust, but they did not act as a buttress for the anterior teeth. The “needle-like” palatines described by Bakhurina (1988) are elongated maxillary palatal rods, as in other anurognathids.
The dorsal and sacral vertebrae were atypically robust.
The sternal complex was the smallest of all anurognathids. The “sternum” identified by Rjabinin (1948) and the “proximal humerus” of Bakhurina (1988) are identified here as a set of manual unguals beneath the pedal digits.
The metacarpus was extremely short and extremely robust. Manual 2.1, 3.1 and 3.2 were discs.
The posterior ilial process was atypically elongated. The anterior and posterior rims of the pelvis were vertical and essentially parallel. Pedal digit V was elongated. Pedal 5.1 reached the ungual of digit IV. The metatarsals were elongated relative to the toes. Pedal digit II extended the furthest as in Jeholopterus.
Batrachognathus was said to have had bristles surrounding the jaws. I found no such structures. What I d id find that was similar were the bristles that emanated from the tail, which curled around near the jaws. See overlay below. |
