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Damassadinium spinosum
Damassadinium spinosum Slimani et al., 2008, p.330–331, figs.3A–F.
NOW Danea. Originally Damassadinium (genric name illegitimate), subsequently (and now) Danea.
Holotype: Slimani et al. 2008, figs.3A–C.
Age: early Danian.
Original description (Slimani et al., 2008):
Damassadinium spinosum sp. nov. Fig. 3
Derivation of name. Latin ‘‘spina’’, spine, with reference to the processes.
Holotype. Sample OH 17, slide 1, EF F57/3 (Fig. 3AeC).
Type locality and stratigraphic horizon. Ouled Haddou section, north of Taza, northern Morocco; marls 65 cm above the K/T boundary, lower Danian.
Diagnosis. Intermediate spherical to ovoidal Damassadinium with tabulation indicated by annulate to soleate and linear complexes of relatively short processes and by occasional intratabular processes. Precingular archeopyle type P(3). Operculum free.
Description. Proximate to proximo-chorate dinoflagellate cyst with a spherical to ovoid central body. No antapical protrusion or distinct process is observed. Cyst wall 0.5-1 µm thick, composed of a smooth, dense endophragm and a fibrous periphragm; both layers closely appressed. Periphragm forms fibrous, acuminate or distally bifid processes that are simple or proximally to medially branched 2-5 times and irregularly connected at their bases by low fibrous ridges forming annulate or soleate and linear process complexes. Distribution of the processes reflects one apical plate, four precingular (1’’, 2’’, 4’’, 5’’) and four postcingular (3’’’, 4’’’, 5’’’, 6’’’) plates and one antapical (1’’’’) plate. Central precingular process complex corresponds to the archeopyle. Processes are occasionally grouped in very reduced clusters that indicate precingular (6’’), postcingular (1’’’, 2’’’) and posterior (1p) intercalary plates (Fig. 3F). Cingulum represented by six linear process complexes. Occasional isolated processes are distributed in sulcal area but do not clearly reflect a tabulation pattern. Intratabular processes occur occasionally and are sometimes joined proximally by low ridges. Apical process is branched and arises within apical process complex. It often consists of a protuberance surmounted by short and slender processes.
Dimensions (in µm). Holotype and range for 10 specimens measured: length of central body 60, 50(55)62; width of central body 60, 45(53)60; length of processes 5-12, 5-12.
Discussion. Damassadinium spinosum sp. nov. is unique in possessing short processes and a tabulation indicated only by process complexes. Damassadinium heterospinosum (Matsuoka, 1983) Fensome et al., 1993 and D. californicum (Drugg, 1967) Fensome et al., 1993 are almost twice as large and possess an antapical protrusion. Both latter species also have strongly fibrous and reticulate walls. Furthermore, the other species of this genus differ essentially from D. spinosum in possessing only septa or ridges.
Stratigraphic occurrence. Samples OH 9e19, planktonic foraminiferal Guembelitria cretacea and Parvularugoglobigerina eugubina zones (lower Danian).
NOW Danea. Originally Damassadinium (genric name illegitimate), subsequently (and now) Danea.
Holotype: Slimani et al. 2008, figs.3A–C.
Age: early Danian.
Original description (Slimani et al., 2008):
Damassadinium spinosum sp. nov. Fig. 3
Derivation of name. Latin ‘‘spina’’, spine, with reference to the processes.
Holotype. Sample OH 17, slide 1, EF F57/3 (Fig. 3AeC).
Type locality and stratigraphic horizon. Ouled Haddou section, north of Taza, northern Morocco; marls 65 cm above the K/T boundary, lower Danian.
Diagnosis. Intermediate spherical to ovoidal Damassadinium with tabulation indicated by annulate to soleate and linear complexes of relatively short processes and by occasional intratabular processes. Precingular archeopyle type P(3). Operculum free.
Description. Proximate to proximo-chorate dinoflagellate cyst with a spherical to ovoid central body. No antapical protrusion or distinct process is observed. Cyst wall 0.5-1 µm thick, composed of a smooth, dense endophragm and a fibrous periphragm; both layers closely appressed. Periphragm forms fibrous, acuminate or distally bifid processes that are simple or proximally to medially branched 2-5 times and irregularly connected at their bases by low fibrous ridges forming annulate or soleate and linear process complexes. Distribution of the processes reflects one apical plate, four precingular (1’’, 2’’, 4’’, 5’’) and four postcingular (3’’’, 4’’’, 5’’’, 6’’’) plates and one antapical (1’’’’) plate. Central precingular process complex corresponds to the archeopyle. Processes are occasionally grouped in very reduced clusters that indicate precingular (6’’), postcingular (1’’’, 2’’’) and posterior (1p) intercalary plates (Fig. 3F). Cingulum represented by six linear process complexes. Occasional isolated processes are distributed in sulcal area but do not clearly reflect a tabulation pattern. Intratabular processes occur occasionally and are sometimes joined proximally by low ridges. Apical process is branched and arises within apical process complex. It often consists of a protuberance surmounted by short and slender processes.
Dimensions (in µm). Holotype and range for 10 specimens measured: length of central body 60, 50(55)62; width of central body 60, 45(53)60; length of processes 5-12, 5-12.
Discussion. Damassadinium spinosum sp. nov. is unique in possessing short processes and a tabulation indicated only by process complexes. Damassadinium heterospinosum (Matsuoka, 1983) Fensome et al., 1993 and D. californicum (Drugg, 1967) Fensome et al., 1993 are almost twice as large and possess an antapical protrusion. Both latter species also have strongly fibrous and reticulate walls. Furthermore, the other species of this genus differ essentially from D. spinosum in possessing only septa or ridges.
Stratigraphic occurrence. Samples OH 9e19, planktonic foraminiferal Guembelitria cretacea and Parvularugoglobigerina eugubina zones (lower Danian).