Petalichthyida, Jaekel, 1911

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 : 20

Petalichthyida indet. ( Fig. 12 )

Petalichthyids (possibly macropetalichthyids) are now evidenced in the Ly Hoa fauna by an anterior ventrolateral plate associated with the proximal portion of a spinal plate (AVL, Sp, Fig. 12 ). In addition, it is probable that the spinal plate fragment figured by Janvier et al. (1997: fig. 4G) also belongs to this taxon. The AVL plate is exposed in internal aspect, but it is so thin that its external ornamentation of concentric ridges is clearly visible in immersion. The Sp plate is ornamented with parallel ridges and bears a lateral series of pointed tubercles. The overall shape of the specimen is almost point-for-point similar to the corresponding part of the thoracic armour in Lunaspis broili Gross, 1961 , from the Emsian of Germany.

Figures

FIG. 12. — Petalichthyida indet., Ly Hoa Formation,?Lower Devonian, Ly Hoa, Quang Binh Province, Vietnam, anterior ventrolateral plate and associated proximal portion of the spinal plate (BT 207m).Abbreviations:AVL, anterior ventrolateral plate; Sp, spinal plate. Scale bar: 10 mm.