A Review of Scriniodinium Klement 1957, Endoscrinium (Klement 1960) Vozzhennikova 1967 and Related Dinoflagellate Cyst Taxa

Abstract

Specimens of the well known and distinctive Jurassic (typically Oxfordian) dinoflagellate cyst species Scriniodinium crystallinum from Australia and New Zealand vary from being nonparatabulate to paratabulate. Where present, the paratabulation, which is manifested by low parasutural ridges on the periphragm, shows a clear dextral torsion, indicating affinity with the gonyaulacacean subfamily Cribroperidinioideae. Other species of Scriniodinium, such as S. pharo and S. playfordii confirm that this genus unequivocally belongs in the subfamily Cribroperidinioideae. Scriniodinium and S. crystallinum are both emended in order to note the cribroperidinioid paratabulation. Endoscrinium, however, exhibits neutral torsion and thus belongs in the subfamily Leptodinioideae. Endoscrinium and its type, E. galeritum, are emended to note this paratabulation style. On the basis of this clear paratabulation difference between Scriniodinium and Endoscrinium, ten species are transferred to the most appropriate genus. Endoscrinium anceps is transferred to Scriniodinium as it has dextral torsion. Endoscrinium acroferum, E. attadalense, E? hauterivianum, E. heikeae, E. indicum, E. irregulare, E? novissimum, E. obscurum and E. reticulatum are all new combinations of taxa with neutral torsion which were previously placed in Scriniodinium. Additionally, Aldorfia warringtonii is transferred to Apteodinium because it displays dextral torsion. Scriniodinium and Endoscrinium peaked worldwide during the late Callovian to early Kimmeridgian. There are differences in the stratigraphical ranges of species of Scriniodinium and Endoscrinium between the Northern and Southern hemispheres. For example, Scriniodinium crystallinum has a younger range top in Australasia than in Europe. However, there are many strong global consistencies with these two important genera and some potential evolutionary trends have been discerned. Endoscrinium has the older range base and this is consistent with the phylogeny of the subfamilies Leptodinioideae and Cribroperidinioideae. c c 0 A B 50 µm 1p '

Middle and Upper Jurassic (Callovian to Kimmeridgian) Palynology of the Onshore Moray Firth Basin, Northeast Scotland

“…jurassica var. The consistent occurrence of Endoscrinium galeritum is also characteristic of the mid Oxfordian (Riding and Fensome, 2002). orbifera, Leptodinium spp., Systematophora areolata, Systematophopra penicillata and Systematophora valensii.…”

“…Gonyaulacysta jurassica subsp. This form has been recorded from the Upper Callovian in England, but in Scotland and areas to the north the range base of this species is in the Lower Oxfordian (Riding and Fensome, 2002). jurassica has been recorded from the Mariae Zone, and its local range base in northeast Scotland within the Bukowskii Subzone is probably due to the sampling/ lithological constraints in the Zone.…”

“…This represents the oldest record of this taxon; the range base of this species was stated to be Oxfordian by Poulsen and Riding (1992). In the case of Scriniodinium crystallinum, this species is present in the late Callovian of England, but its range base in Scotland and areas to the north is early Oxfordian (Riding and Fensome, 2002). These are those of Gonyaulacysta jurassica subsp.…”

“…jurassica, Hystrichosphaeridium? In England and Germany, the range base of Scriniodinium crystallinum is consistently within the late Callovian (Woollam, 1980;Riding, 1982;Prauss, 1989;Feist-Burkhardt and Wille, 1992;Riding and Fensome, 2002). Endoscrinium luridum, Gonyaulacysta jurassica subsp.…”

“…Endoscrinium luridum, Gonyaulacysta jurassica subsp. The range base of Scriniodinium crystallinum in western Scotland and elsewhere in the Boreal Realm is within the earliest Oxfordian Mariae Zone and equivalents (Riding and Thomas, 1997;Riding and Fensome, 2002). longicornis (large morphotype) and Systematophora penicillata have their inceptions in the mid Oxfordian (Woollam and Riding, 1983;Riding and Thomas, 1997).…”