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Trinovantedinium xylochoporum
Trinovantedinium? xylochoporum De Verteuil and Norris, 1992
De Verteuil and Norris, 1992 questionably included this species in Trinovantedinium.
Holotype: De Verteuil and Norris, 1992, pl.6, fig.1
Locus typicus: St. Leonard Member ("Bed 18") of the Choptank Formation, north of Scientists Cliffs but south of Parker Creek, west shore of Chesapeake Bay, Calvert County Maryland
Stratum typicum: Middle Miocene
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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.
Trinovantedinium? xylochoporum de Verteuil and Norris (1992). Diagnosis from de Verteuil and Norris (1992, p.416), skolochorate intermediate, pigmented, protoperidiniacean cysts with rounded elongate or subcircular outline when compressed dorsoventrally, or with poorly developed antapical lobes. Cyst wall autophragmal and less than 0.5 µm thick bearing many penitabular processes that are hollow and distally closed with a circular or taeniate cross section. Processes are simple or complex and comprise a tubiform or tapering proximal shaft that ramifies distally in first, second, third and higher order opposite furcations. Archeopyle is 2a hexa. Size: length 36-66 µm, width 38-62 µm, processes 8-20 µm. The branching pattern of the processes is reminiscent of that in Reticulatosphaera actinocoronata. The species is provisionally included in Trinovantedinium because it has penitabular processes and an intercalary archeopyle.
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Original diagnosis: De Verteuil and Norris, 1992, p. 416, 418
Skolochorate, intermediate, pigmented protoperidiniacean cysts with rounded elongate or subcircular outline when compressed dorsoventrally, or with poorly developed antapical lobes. Cyst wall autophragmal and less than 0.5 Ám thick bearing many penitabular processes that are hollow and distally closed with a circular or taeniate cross section. Processes are simple or complex and comprise a tubiform or tapering proximal shaft that ramifies distally in first, second, third and higher order opposite furcations. Archeopyle is 2a hexa.
Original description: De Verteuil and Norris, 1992, p. 418
The epicyst in dorsoventral compression is semi-elliptical in outline and has no apical prominence. If not symmetrical, the hypocyst rarely has two rounded antapical lobes separated by a shallow depression. The equatorial width, in lateral compression, is less than either the polar height, or the equatorial width in dorsoventral compression. The wall is psilate or scabrate and comprises two very thin layers that usually appear autophragmal. The penitabular processes are variably robust and may appear solid or may be distally solid, but they do not form proximally joined linear or arcuate complexes. The cingulum is non-indented but can be poorly defined on some specimens by the cingular processes. The sulcus is straight, relatively broad (15-20% of equatorial diameter) and, as with the intratabular and ventral posterior areas, generally free of processes. The archeopyle is 2a hexa intercalary with the operculum free. Further details of tabulation are unclear.
Dimensions. Length, 36(51)66 Ám; holotype, 62 Ám. Equatorial width, 38(45)62 Ám; holotype, 56 Ám. Processes, 8-20 Ám; holotype 14-18 Ám. Eighteen specimens measured.
Discussion. Trinovantedinium? xylochoporum is distinctive because of the complex branching pattern of its processes. The similarity of this structure in T.? xylochoporum and the coeval gonyaulacoid species Reticulatosphaera actinocoronata (Benedek 1972) Bujak & Matsuoka 1986 is striking. The new species is provisionally assigned to Trinovantedinium because it has penitabular processes and an intercalary archeopyle.
Affinities:
De Verteuil and Norris, 1992, p. 420: Trinovantedinium? xylochoporum is distinghuished from all other Protoperidiniacean cysts by its skolochorate structure and distinctive tree-like processes.
De Verteuil and Norris, 1992 questionably included this species in Trinovantedinium.
Holotype: De Verteuil and Norris, 1992, pl.6, fig.1
Locus typicus: St. Leonard Member ("Bed 18") of the Choptank Formation, north of Scientists Cliffs but south of Parker Creek, west shore of Chesapeake Bay, Calvert County Maryland
Stratum typicum: Middle Miocene
--------------------------------------------------
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Trinovantedinium? xylochoporum de Verteuil and Norris (1992). Diagnosis from de Verteuil and Norris (1992, p.416), skolochorate intermediate, pigmented, protoperidiniacean cysts with rounded elongate or subcircular outline when compressed dorsoventrally, or with poorly developed antapical lobes. Cyst wall autophragmal and less than 0.5 µm thick bearing many penitabular processes that are hollow and distally closed with a circular or taeniate cross section. Processes are simple or complex and comprise a tubiform or tapering proximal shaft that ramifies distally in first, second, third and higher order opposite furcations. Archeopyle is 2a hexa. Size: length 36-66 µm, width 38-62 µm, processes 8-20 µm. The branching pattern of the processes is reminiscent of that in Reticulatosphaera actinocoronata. The species is provisionally included in Trinovantedinium because it has penitabular processes and an intercalary archeopyle.
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Original diagnosis: De Verteuil and Norris, 1992, p. 416, 418
Skolochorate, intermediate, pigmented protoperidiniacean cysts with rounded elongate or subcircular outline when compressed dorsoventrally, or with poorly developed antapical lobes. Cyst wall autophragmal and less than 0.5 Ám thick bearing many penitabular processes that are hollow and distally closed with a circular or taeniate cross section. Processes are simple or complex and comprise a tubiform or tapering proximal shaft that ramifies distally in first, second, third and higher order opposite furcations. Archeopyle is 2a hexa.
Original description: De Verteuil and Norris, 1992, p. 418
The epicyst in dorsoventral compression is semi-elliptical in outline and has no apical prominence. If not symmetrical, the hypocyst rarely has two rounded antapical lobes separated by a shallow depression. The equatorial width, in lateral compression, is less than either the polar height, or the equatorial width in dorsoventral compression. The wall is psilate or scabrate and comprises two very thin layers that usually appear autophragmal. The penitabular processes are variably robust and may appear solid or may be distally solid, but they do not form proximally joined linear or arcuate complexes. The cingulum is non-indented but can be poorly defined on some specimens by the cingular processes. The sulcus is straight, relatively broad (15-20% of equatorial diameter) and, as with the intratabular and ventral posterior areas, generally free of processes. The archeopyle is 2a hexa intercalary with the operculum free. Further details of tabulation are unclear.
Dimensions. Length, 36(51)66 Ám; holotype, 62 Ám. Equatorial width, 38(45)62 Ám; holotype, 56 Ám. Processes, 8-20 Ám; holotype 14-18 Ám. Eighteen specimens measured.
Discussion. Trinovantedinium? xylochoporum is distinctive because of the complex branching pattern of its processes. The similarity of this structure in T.? xylochoporum and the coeval gonyaulacoid species Reticulatosphaera actinocoronata (Benedek 1972) Bujak & Matsuoka 1986 is striking. The new species is provisionally assigned to Trinovantedinium because it has penitabular processes and an intercalary archeopyle.
Affinities:
De Verteuil and Norris, 1992, p. 420: Trinovantedinium? xylochoporum is distinghuished from all other Protoperidiniacean cysts by its skolochorate structure and distinctive tree-like processes.