Meet a new fossorial fossil dinosaur,
perfectly preserved in its own burrow.
Yang et al. 2020 bring us
self-buried specimens of Changmiania liaoningensis (Yixian, Early Creteceous; Figs. 1–3).
The authors nest this ornithischian
as the basalmost member of the clade Ornithopoda (= duckbills, etc.; Fig. y).
the large reptile tree (LRT, 1733+ taxa; subset Fig. x) nests Changmiania (Figs. 1–3) with Kulindadromeus (Fig. 4) and Heterodontosaurus (Fig. 5). That’s several nodes apart from the clade Ornithopoda in the LRT (Fig. x).
Digging (fossorial behavior)
traits found in Changmiania proposed by the authors include:
- fused premaxillae
- nasal laterally expanded overhanging the maxillas
- shortened neck formed by only six cervical vertebrae;
- neural spines of the sacral vertebrae completely fused together, forming a craniocaudally-elongated continuous bar;
- fused scapulocoracoid with prominent scapular spine;
- and paired ilia symmetrically inclined dorsomedially, partially
covering the sacrum in dorsal view.
Several ornithischian taxa
(Orodromeus, Oryctodromeus, and Zephyrosaurus) have also demonstrated (or suggested by phylogenetic bracketing) fossorial behavior. Heterodontosaurus (Figs. 5, 6) shares traits #1, 2 and 3. Heterodontosaurus has longer fingers #2 and #3 (for digging?).
It’s worth noting
that many extant birds dig burrows, too. They use their bills to peck and their feet to sweep. Progress is often slow. Here’s an online article discussing birds that use and dig burrows.
Here’s a YouTube video
of a belted kingfisher working on its own burrow. Much is not shown, but the feet are back-kicking out the rubble, presumably produced by the pecking of the strong beak at the back wall of the burrow.
Yang Y, Wu W, Dieudonne P-E and Godefroit P 2020. A new basal ornithopod dinosaur from the Lower Cretaceous of China. PeerJ 8:e9832 DOI 10.7717/peerj.9832