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Florentinia laciniata ssp. laciniata

Florentinia laciniata ssp. laciniata

Autonym.

Holotype: Davey and Verdier 1973, pl. 2, figs. 1,3
Locus typicus: Saint Florentin (section II ), Chemin du Cimetiere, France.
Stratum typicum: Late Albian
Age: Late Albian-Early Cenomanian

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G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.

Florentinia laciniata Davey and Verdier, 1973, has large, complex pre- and postcingular processes, a distinctive, long, tubular antapical, smooth to microgranular wall and, typically, a combination archeopyle of apicals plus 3", very rarely the apical region may remain attached with perhaps an incipient apical-precingular tear. Distally the large processes have two or more truncated tubules. The cingular processes have elongate narrow bases from which usually arise two long tubules. Processes 2"’ to 5"’ are especially large. Antapical process typically open. F.ferox has less complex processes which are acuminate distally and does not have a distinctive antapical process. Size: central body 36-55 µm, process length 26-49 µm..
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Original diagnosis: Davey and Verdier 1973, p. 186: Florentinia laciniata
The cyst wall is smooth to granular and bears processes of considerable size variation which are basically thin walled, hollow, often striate and give rise to distally to truncated tubules. The apical processes are relatively narrow and are composed of one or two tubules. The precingular processes are large, having broad bases but flattening distally; they divide medially to give 2 or more tubules. The cingular processes have elongate narrow bases from which usually arise two long tubules. In the postcingular series there are 4 large (larger than the precingular processes), broad based processes which are flattened distally and bear a number of tubules; these processes (2"', 3"', 4" and 5"') vary in size with process 3 ' being the smallest of the series and 5"' being the largest. The first postcingular (1"') and the posterior intercalary ( lp) processes are reduced and are difficult to distinguish from the sulcal processes. The latter are thin, simple or bifurcating tubules. The antapical process is long and tubular, typically open and occasionally gives rise distally to small tubules. The archaeopyle is typically a combination of apical plates (1-4') and precingular plate (3"); very rarely the apical region may remain attached with perhaps an incipient apical-precingular tear being present.

Dimensions: Holotype Range
Central bocly diameter 36x44 Á 36 (46) 55 Á
Process length...... 15-30 Á 26 (36) 49 Á maximum

Original description: Davey and Verdier 1973, p. 186, 187: Florentinia laciniata
Occasionally, the wall beneath the larger processes is notlceably more granular than usual and tends to be elevated; these areas, which are limited by the proximal margins of the processes, may be angular and presumably parallel the plate boun- daries. As noted in the diagnosis all the processes, with the occasional exception of the antapical, bear or divide to give tubules. These are always truncated distally and it is inferred that such a truncation indicates that the lumen of the process is in contact with the exterior. This is sometimes obviously the case but at other times it is possible that the tubule end may be infilled. The distal margin of the tubules is typically entire; the antapical process may be denticulate. Occasionally the larger processes may be convex distally (pl . 2, fig. 9) with the tubules arising from the margins of this convexity.
Only one specimen which has the apical region in place has been observed.

Remarks: The type of archaeopyle and the structure and differentiation of the process distinguish F. Iaciniata from all previously described species. It is similar to <> ferox (Deflandre, 1937a) which differs significantly by the less complex processes, which are acuminate distally, and the lack of a distinctive antapical process. Hystrichokolpoma eisenacki Williams & Downie (1966a) is also very similar, differing only in details of process morphology and the possession of an apical archaeopyle. The specimen figured by Davey, 1969 (pl. 9, figs. 5-7) rnistakenly as Hystrichokolpoma ferox clearly illustrates the salient features of F. Iaciniata.

Reported Occurrence: Aptian, Germany (Eisenack, 1958). Albian to Cenomanian, Australia, England, Germany (Alberti, 1961; Cookson & Eisenack, 1962b; Cookson & Hughes, 1964; Clarke & Verdier, 1967; Davey, 1969).
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Remarks: Davey and Verdier 1976, p. 318
F. Iaciniata is a large species and is distinguished from other species of this genus by the large, distinctive antapical process and several complex processes. No other species appears to be very closely related and identification is generally easy.
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