THE DIPNOAN SPECIES, SORBITORHYNCHUS-DELEASKITUS, FROM THE LOWER DEVONIAN OF GUANGXI, CHINA

A dipnoan species from the Emsian of Guangxi, China, Sorbitorhynchus d eleaskitus, which has previously been diagnosed in the appendix to a m ore general paper on dipnoan phylogeny (Campbell & Barwick 1990), is d escribed in detail. The head is large and heavily ossified, with cosmi ne on the external dermal bones. The dental plates are thick and have few poorly defined large tuberosities towards their anterolateral edge s. It is the only Early Devonian dipnoan for which the full hyoid arch , gular, basibranchial, and submandibular plates are preserved, and in which the parasphenoid is clearly defined. In many features the genus is more advanced than Dipnorhynchus, but in none is it more advanced than Dipterus, apart from the loss of the buccohypophysial foramen. It gives a new perspective on late Emsian evolution of the group, and re inforces our concept of an independently developing dentine-plated lin e contemporaneous with a true tooth-plated line.