Back
Cyclonephelium intermedium

From Fensome et al., 2019:
(Khowaja-Ateequzzaman and Jain, 1990, p.178, pl.2, figs.1–5; text-figs.2A–B) Fensome et al. 2019a, p.41.
Holotype: Khowaja-Ateequzzaman and Jain, 1990, pl.2, figs.1–5; text-figs.2A–B; Fauconnier and Masure, 2004, pl.12, figs.5,7–9; Fensome et al., 2019a, figs.14O–P.
Originally Cauveridinium, subsequently (and now) Cyclonephelium. Taxonomic synonyms: Cauveridinium indicum and Cauveridinium longispinosum, both according to Fensome et al. (2019a, p.41).
Fensome et al. (2019a, p.41) selected "intermedium" as senior because the epithets "indicum" and longispinosum" are already in use in Cyclonephelium.
Age: Turonian–Santonian.

---------------------------------------------------------------------------------------------------

Original description: [Khowaja-Ateequzzaman and Jain, 1990, p.178]

Diagnosis:
Cyst skolochorate, lenticular, subcircular; apex obtusely angular; antapex with two reduced, unequal prominences, separated by a concavity; autophragm smooth, ornamented with processes; processes restricted to circumferential border zone, absent on central dorsal and central ventral areas, solid, branched, variable in length and breadth, proximally connected, a few distally fused; archaeopyle apical, type (4A), operculum free.

Description:
Shape: Cyst dorso-ventrally compressed, subcircular, sulcal notch offset to left of cyst (Textfig. 2B), apical margin obtusely angular; antapex with two reduced, unequal prominences separated by a concavity.
Wall relationship: Autophragm only.
Wall features: No parasutural features, autophragm smooth, ornamented with processes restricted to circumferential border zone, absent on central dorsal and central ventral areas; processes solid, branched, variable in size, mostly proximally connected through ridges; others single, unconnected; some distally fused (Text-fig. 2A).
Paratabulation: Indicated by archaeopyle alone.
Archaeopyle: Apical, type (4A), operculum free.

Dimensions: Holotype Range
Size of body 58 x 64 µm 55 75 x 52-64 µm (without operculum)
Length of processes 8-20 µm 6-22 µm

Affinities:
Cauveridinium intermedium is an interesting species having features of both Cyclonephelium distinctum Deflandre and Cookson 1955 and its own. The occurrence of simple and unconnected processes suggests comparison with C. distinctum but proximally connected adjacent processes through a ridge differentiate it from Cyclonephelium. The other two species, Cauveridinium indicum and C. longispinosum, differ from C. intermedium in that differentiated autophragm.

------------------------------------------------------------------------
Comments Fensome et al., 2019a:

Khowaja-Ateequzzaman & Jain (1990) described this species, in part, as follows: “processes restricted to circumferential border zone, absent on central dorsal and central ventra areas … proximally connected through thick ridges and a few mostly on dorsal surface also laterally connected through septa ….” From illustrations in the protologue it appears that the ornament height is less than 25% of the maximum cyst width: hence we consider this species to belong to Cyclonephelium and Cauveridinium (of which this species is type) to be a taxonomic junior synonym of Cyclonephelium. Khowaja-Ateequzzaman & Jain (1990) described two other species of Cauveridinium, but these appear to intergrade with the type and may be differentiated only with difficulty. Hence we consider Cauveridinium intermedium and Cauveridinium longispinosum to be taxonomic junior synonyms of Cyclonephelium (al. Cauveridinium) indicum.
Feedback/Report bug