Microstructural diversity of the stylophyllid (Scleractinia) skeleton Author Stolarski, Jarosław Author Russo, Antonio text Acta Palaeontologica Polonica 2002 2002-12-31 47 4 651 666 journal article 300553 10.5281/zenodo.13174414 9dc1c0c7-71e3-4e31-8d82-19e811e909d5 1732-2421 13174414 Family Stylophyllidae Frech, 1890 Frech (1890) distinguished three Triassic genera within the Stylophyllidae : Stylophyllum , Stylophyllopsis and Meandrostylis (asasubgenusof Stylophyllum ).Roniewicz(1989),ina comprehensive revision of stylophyllid taxa, listed the following Triassic and Jurassic stylophyllid genera (stratigraphic ranges in brackets): Stylophyllum Reuss, 1854 (Norian– Rhetian); Stylophyllopsis Frech, 1890 (Anisian–Pliensbachian); Meandrostylis Frech, 1890 (Rhetian); Coccophylum Reuss, 1864 (Norian–Rhetian); Pinacophyllum Frech, 1890 (Norian–Rhetian); Anthostylis Roniewicz, 1989 (Rhetian);? Oppelismilia Duncan, 1867 (Hettangian–Sinnemurian);? Leptophyllia Duncan, 1868 (Hettangian–Sinemurian); and Heterastraea Tomes, 1888 (Hettangian–Sinnemurian). Roniewicz and Morycowa (1989) also listed among stylophyllids Discocoenia Tomes, 1884 (Hettangian), Discocoeniopsis Beauvais, 1976 (Hettangian–Sinemurian) and Phacelepismilia Beauvais, 1976 (Hettangian–Sinemurian), and possibly three following Sinemurian–Plinsbachian taxa described by Turnsek et al. (1975) : “ Pinacophyllum ”, “ Isastraea ”, and “ Paraphyllogyra ”. Generic taxonomic criteria include mode of growth, colony type , type of septal ornamentation, wall structure, and type of columella. Many taxa that are currently classified among stylophyllids, originally were assigned in the “catch−all” genus Montlivaltia Lamouroux, 1821 . Also Chapuis and Dewalque (1853) included in this genus solitary, discoidal M. haimei , a species recognized herein among coral collection from Longi. Alloiteau (1957: 105) , aware of the confused status of Montlivaltia , designated M. haimei a type species of Haimeicyclus . Eight specimens of M. haimei from Villers−sur−Semoy ( Belgium ) examined by Alloiteau (1957) have been described as lacking endotheca and synapticulae. Photographs of two of these specimens housed at Museum National d’Histoire Naturelle, Paris (out of three specimens and one thin transverse section) kindly provided to me by Dr. Bernard Lathuiliere (Nancy), demonstrate the accuracy of Alloiteau’s description. On the contrary, apparently the same coralla used by Beauvais (1986) to propose erroneously Haimeicyclus asanewgenericnamefor M. haimei havebeen characterized as possessing endotheca composed of thin dissepiments, sparse synapticulae, and septa with short menianae, features not recognized in Alloiteau’s description. Clearly, from these two different descriptions of apparently the same coral samples, only Alloiteau’s (1957) correspond to the original Chapuis and Dewalque’s (1853) description of M. haimei . Though taxa with discoidal coralla already have been included to stylophyllids (i.e., Discocoenia Tomes, 1884 and Discocoeniopsis Beauvais, 1976 ), Haimeicyclus seems to be a valid genus. Type species of Discocoenia ( D. bononiensis Tomes, 1884 ), D. ruperti Duncan, 1867 , and D. radiata Duncan, 1867 were included in the genus by Beauvais (1976) , and have only a slightly crenulated distal septal margin. Though, dense granulations on septal faces ( Beauvais 1970 : fig. 1; Beauvais 1976 : figs. 31, 32) are shared with stylophyllids, however, lack of septal spines make a stylophyllid affiliation of the genus questionable. On the other hand, type species of Discocoeniopsis , D. nummiformis ( Duncan, 1867 ) from the Sinemurian of England , has stylophyllid−like spines on septal distal margin ( Beauvais 1976: 51 ). However, prominent costosepta and epitheca extending only partially on the flat corallum basis, point toward a relationship with the skeletal elements in the thecocyathid genus Discocyathus Milne Edwards and Haime, 1848 than those in stylophyllids (see e.g., Roniewicz and Stolarski 1999 : fig. 12B, C). Clearly, D. nummiformis , which lacks pali and a lamellar columella, is not congeneric with Discocyathus , though differences in development of skeletal elements make its position very distinct among stylophyllids.