Brachythoraci, Gross, 1932

Racheboeuf, Patrick, Phuong, Ta Hoa, Hung, Nguyen Huu, Feist, Monique & Janvier, Philippe, 2006, Brachiopods, crustaceans, vertebrates, and charophytes from the Devonian Ly Hoa, Nam Can and Dong Tho formations of Central Vietnam, Geodiversitas 28 (1), pp. 5-36 : 19

Brachythoraci fam. indet. ( Fig. 11 )

A few plate fragments also suggest the presence of a second arthrodire, and presumably yet another brachythoracid in the Ly Hoa fauna. In particular, a portion of a relatively large, gently curved plate, ornamented with rounded tubercles and bearing a large overlap area (oa, Fig. 11 ), belongs to an arthrodire, which is certainly different from Lyhoalepis because all the thoracic plates and probably the skull-roof plates of the latter are fused and show no overlap surfaces (Tong-Dzuy et al. 1994). The shape of the overlap area and the curvature of this plate is somewhat suggestive of the dorsal part of the PDL plate of such a brachythoracid as Coccosteus ( Miles & Westoll 1968: fig. 32).

Figures

FIG. 11. — Brachythoraci gen.et sp.indet.,Ly Hoa Formation,?Lower Devonian, Ly Hoa, Quang Binh Province,Vietnam,elastomer cast of an incomplete plate of the trunk armour, in external view (BT 207m). Abbreviation: oa, overlap area. Scale bar: 5 mm.