. Bulletin of the Natural Histort Museum. Geology series. 74 M. RUTA. M'5 B Fig. 9 Reticulocarpos hanusi Jefferies & Prokop. Middle Ordovician, Llanvim, Sarka Formation, Czech Republic. Schematic reconstruction of external aspect. A, dorsal view. B, ventral view (redrawn and modified after Jefferies & Prokop, 1972 and Cripps & Daley, 1994). of Juliaecarpus show their maximum degree of curvature at the level of plates M', and M„ whereas in Reticulocarpos, such margins are more strongly convex at the level of M^ and M^, on the right side of the theca, and of M', and M',, on its left
. Bulletin of the Natural Histort Museum. Geology series. 74 M. RUTA. M'5 B Fig. 9 Reticulocarpos hanusi Jefferies & Prokop. Middle Ordovician, Llanvim, Sarka Formation, Czech Republic. Schematic reconstruction of external aspect. A, dorsal view. B, ventral view (redrawn and modified after Jefferies & Prokop, 1972 and Cripps & Daley, 1994). of Juliaecarpus show their maximum degree of curvature at the level of plates M', and M„ whereas in Reticulocarpos, such margins are more strongly convex at the level of M^ and M^, on the right side of the theca, and of M', and M',, on its left side. In addition, the dorso-lateral projections of the marginalia of Juliaecarpus are slightly to much wider than their ventral projec- tions, whereas in Reticulocarpos, the difference in width between the two kinds of projections is much smaller. 2. Unlike Reticulocarpos, Juliaecarpus possesses a large suranal plate. This plate is probably not unique to Juliaecarpus, as I shall explain below, because an enlarged plate occupying the posterior part of the dorsal integument seems to have been present also in Beryllia and Domfrontia (see discussion of these genera below). 3. In Juliaecarpus, plates M'^ and M^ do not send medial projections forming a dorsal bar as in Reticulocarpos. In the stylophoran phylogeny presented by Parsley (1997, 1998), the presence of a dorsal bar characterizes a clade uniting Reticulocarpos, Prokopicystis and Hanusia, contrary to the hypotheses of rela- tionships presented by Cripps (1991) and Cripps & Daley (1994) (but see also Daley, 1992). 4. Plates M', and M, of Juliaecarpus are less strongly convex laterally than their namesakes in Reticulocarpos and their dorso- lateral projections are slightly wider than those of more posterior marginalia. The dorso-lateral projections of M', and M, contrib- ute only in part to the antero-lateral angles of the theca, whereas in some other ankyroids (but not in Reticulocarpos), these marginalia send more str
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