Zardinophyllidae Montanaro-Gallitelli, 1975

Gretz, Mélanie, Lathuilière, Bernard & Martini, Rossana, 2015, A new coral with simplified morphology from the oldest known Hettangian (Early Jurassic) reef in southern France, Acta Palaeontologica Polonica 60 (2), pp. 277-286 : 278-279

Family Zardinophyllidae Montanaro-Gallitelli, 1975

Remarks.—The suborder Pachythecaliina Eliášová, 1976 is known from the Late Triassic to Maastrichtian. The systematic position of Pachythecaliina is controversial in the literature ( Kołodziej 2003; Kołodziej et al. 2012). Indeed, certain authors distinguish this suborder instead of the suborder Amphiastreina (e.g., Stolarski and Roniewicz 2001; Stolarski and Russo 2001; Kołodziej 2003; Roniewicz 2008; Melnikova and Roniewicz 2012; Morycowa 2012) as others still accept the priority of Amphiastreina ( Kołodziej et al. 2012). According to Roniewicz and Stolarski (2001), the families Zardinophyllidae Montanaro-Gallitelli, 1975 (=junior synonym Pachythecalidae Cuif, 1975 ) and Amphiastreidae Ogilvie, 1987 represent the suborder Pachythecaliina sensu stricto ( Stolarski and Russo 2001). Other post-Triassic groups of Mesozoic have been attributed to this suborder and they represent the Pachythecaliina sensu lato ( Stolarski and Russo 2001). These groups have no typical pachythecal wall, which belongs to diagnostic features of this suborder (or the state of their preservation does not permit to recognise them) and thus their affinity with pachythecaliines was based on the combination of characters or by the absence of characters that permitted to link them with other Jurassic scleractinians ( Stolarski and Russo 2001). These corals are: Heterocoeniidae Oppenheim, 1930 , Carolastraeidae Eliášová, 1976 , Intersmiliidae Melnikova and Roniewicz, 1976 and Donacosmiliidae Krasnov, 1970 . It has to be noticed that the phylogenetic relationship of heterocoeniids is controversial because most authors classify them into the suborder Heterocoeniina Beauvais, 1977 (see Kołodziej 1995; Kołodziej et al. 2012). Intersmilids and carolastraeids are similar and their only significant difference is the corallite symmetry that is respectively radial and bilateral ( Stolarski and Russo 2001). The principal characteristic that link these groups with pachythecaliines are the smooth septal faces that are rare among the coeval scleractinians ( Stolarski and Russo 2001). Donacosmiliids have similarities with amphiastreids but differ from them by their quasi-radial symmetry and lateral budding ( Stolarski and Russo 2001). The stratigraphic distribution of pachythecal corals for the Triassic–Jurassic interval inspired from Stolarski and Russo (2001) is presented in the Fig. 2 .

Pachythecaliine sensu stricto occupy a special place among post-Paleozoic corals ( Kołodziej 2003). Indeed, Eliášová (1978) included the suborder Pachythecaliina in the order Hexanthiniaria Montanaro-Gallitelli, 1975 that is in some aspects intermediate between Rugosa and Scleractinia . By their peculiar morphological characteristics, zardinophyllids, amphiastreids and related families were considered by various authors (e.g., Koby 1888; Montanaro-Gallitelli 1975; Cuif 1975, 1980; Eliášová 1978, Melnikova and Roniewicz 1976; Stolarski 1996) as descendants of Rugosa ( Kołodziej 2003). Pachythecaliines sensu stricto, have some distinct morphological characters that are comparable to those of the Palaeozoic plerophylline rugosans (Roniewicz and Stolarski 2001; Stolarski and Russo 2001; Kołodziej et al. 2012). Theses aspects are an early ontogeny and a skeletal architecture composed of a pachythecal wall and septa arranged in a bilateral symmetry that are commonly deeply located in the calice. However, Pachythecaliines ssp. have an aragonitic skeletal mineralogy and?quasi-cyclic septal development in the adult stage that attest their link with scleractinians (Roniewicz and Stolarski 2001; Stolarski and Russo 2001).Amphiastreids differ principally from the zardinophyllids by their mode of budding that is “Taschenknospung” ( Stolarski and Russo 2001).

The Triassic–Jurassic family Zardinophyllidae is composed in addition to the new genus presented in this work, of five other genera that are Pachydendron Cuif, 1975 , Pachysolenia Cuif, 1975 , Pachythecalis Cuif, 1975 , Zardinophyllum Montanaro-Galitelli, 1975 , and Pachysmilia, Melnikova, 1989 . The morphological characters of the genus Zardinophyllum would indicate that this genus could represent an “ideal transitional form” between rugosans and non scleractinian, hexanthiniarian post paleozoic corals ( Stolarski 1999; Roniewicz and Stolarski 2001). The link between Paleozoic and post-Paleozoic corals has been controversial for a long time (e.g., Oliver 1980; Fedorowski 1997) especially because no Early Triassic skeletonised anthozoans were found. In this debate, Zardinophyllum was considered either as “an abezrrant scleractinian” (Oliver 1981) or a Hexanthiniaria ( Montanaro-Gallitelli 1975). This question is now renewed by molecular approaches and the finding of Ordovician Kilbuchophyllida ( Scrutton and Clarkson 1991) interpreted as the earliest fossil scleractinian coral record ( Stolarski et al. 2011)

Figures

Fig. 2. Stratigraphic distribution of pachythecal corals and related genera inspired from Stolarski and Russo (2001) and modified. As an approximation, a vertical bar indicates a full stage when such corals were identified in the stage. When a single stage lacks such corals between two stages with such corals, the black bar was elongated. By approximation, Štramberk limestone was considered Tithonian. This figure shows only the Triassic– Jurassic range of Pachythecaliines but most of Jurassic genera occur also in the Cretaceous.