Back
Dinogymnium lamarense
Dinogymnium lamarense Jaramillo and Yepes, 1994, p.5-6, pl.2, figs.13-18.
Name not validly published: lodgment of holotype not specified.
Holotype: Jaramillo and Yepes, 1994, pl.2, figs.13-15.
Age: Santonian.
------------------------------------------------------
Original description (Jaramillo, undergraduate thesis)
Dinogymniurn lamarense nov. sp. Plate. 4 Phot. 1-7
Name derivation: Latin "Märe" : The sea
Locus typicus: Umbale creek, 3 °45' N-75 °15' W, 01tega municipality, Tolima Department, Colombia.
Stratum typicum: "Nivel de Lutitas", Olini Group, Upper Magdalena Valley, The Holotype first occurrence is 28 mts. over the "Lidita Inferior" base.
Holotype: Length: 42 µm, width: 28.5 µm, CI: 56, Slide JY 17A, 37X23 mm. Plate 4 Phot.1-3
Paratypes: Slide JY 17 A-B-C. Plate 4 Phot. 4-7
Diagnosis: Biconical "test" with a strongly antapical horn, "epitest" longer than "hypotest", cingulum index (CI): 59. 7, surface with granules over the complete wall of the "test", absent or few narrow longitudinal libs.
Description: Biconical shape , autophragm only, non-parasutural features, antapical horn, absent to few narrow longitudinal ribs (0-6) present in the apex or antapex, the ribs start in the cingulum, but do not touch the polar areas, a heterocostate pattern is not present; autophragm with granules over the entire wall of the "test", paratabulation is not indicated. Apical archeopyle, operculum generally absent, but when present is attached ventrally or dorsally, cingulum is indicated by an equatorial depression, CI: 59. 7 (range 50-84), parasulcus indicated by a shallow concavity, only present in the antapical sector.
Size and Statistical data: The statistical data were obtained from measurement of 70 specimens. Width 35.1 µm (range 8-65 µm) (text-Fig. 4); Cingulum index: 59.7 (range 50- 84)(text-Fig. 5) Length: 61.8 µm (range 37-85 µm) (text-Fig. 6). The width is strongly affected by postdepositional compression, so that a frequency distribution plotting of (Width/Lenght )* 100 was constructed (text-Fig. 7). The four graphics (Text-Fig 4,5,6,7) of frequency distribution clearly suggest a monospecific poblation. The scatter diagram Lenght vs Width (text-Fig 8) shows a high c01Telation coefficient (0.8), in order to calculate the reduced major axes of the scatter , the method of regression analysis was used. The formula of the line is Y=l.4 +1.27 X, such formula maybe could be an important characteristic in order to identify species. The low correlation coefficient for length vs CI (0.3) (Tex-Fig. 9) shows that CI is independent of size, increasing its taxonomic value as index key to identificate species in the Order Gymnonidial.
Comparison: D. lamarense differs from D. acuminatum Evitt et al, in having fewer ribs (0-6), a strongly antapical horn, an unthickened ridge along the cingulum, a bigger CI mid granulation over apex and antapex. A. euclaense (Cookson & Eisenack)Lentin & Vozzhennikova has not ribs in the "hypotest" and has a different outline. D. digitus has a less notorious granulation than D. lamarense and does not have an antapical horn.
------------------------------------------------------
Name not validly published: lodgment of holotype not specified.
Holotype: Jaramillo and Yepes, 1994, pl.2, figs.13-15.
Age: Santonian.
------------------------------------------------------
Original description (Jaramillo, undergraduate thesis)
Dinogymniurn lamarense nov. sp. Plate. 4 Phot. 1-7
Name derivation: Latin "Märe" : The sea
Locus typicus: Umbale creek, 3 °45' N-75 °15' W, 01tega municipality, Tolima Department, Colombia.
Stratum typicum: "Nivel de Lutitas", Olini Group, Upper Magdalena Valley, The Holotype first occurrence is 28 mts. over the "Lidita Inferior" base.
Holotype: Length: 42 µm, width: 28.5 µm, CI: 56, Slide JY 17A, 37X23 mm. Plate 4 Phot.1-3
Paratypes: Slide JY 17 A-B-C. Plate 4 Phot. 4-7
Diagnosis: Biconical "test" with a strongly antapical horn, "epitest" longer than "hypotest", cingulum index (CI): 59. 7, surface with granules over the complete wall of the "test", absent or few narrow longitudinal libs.
Description: Biconical shape , autophragm only, non-parasutural features, antapical horn, absent to few narrow longitudinal ribs (0-6) present in the apex or antapex, the ribs start in the cingulum, but do not touch the polar areas, a heterocostate pattern is not present; autophragm with granules over the entire wall of the "test", paratabulation is not indicated. Apical archeopyle, operculum generally absent, but when present is attached ventrally or dorsally, cingulum is indicated by an equatorial depression, CI: 59. 7 (range 50-84), parasulcus indicated by a shallow concavity, only present in the antapical sector.
Size and Statistical data: The statistical data were obtained from measurement of 70 specimens. Width 35.1 µm (range 8-65 µm) (text-Fig. 4); Cingulum index: 59.7 (range 50- 84)(text-Fig. 5) Length: 61.8 µm (range 37-85 µm) (text-Fig. 6). The width is strongly affected by postdepositional compression, so that a frequency distribution plotting of (Width/Lenght )* 100 was constructed (text-Fig. 7). The four graphics (Text-Fig 4,5,6,7) of frequency distribution clearly suggest a monospecific poblation. The scatter diagram Lenght vs Width (text-Fig 8) shows a high c01Telation coefficient (0.8), in order to calculate the reduced major axes of the scatter , the method of regression analysis was used. The formula of the line is Y=l.4 +1.27 X, such formula maybe could be an important characteristic in order to identify species. The low correlation coefficient for length vs CI (0.3) (Tex-Fig. 9) shows that CI is independent of size, increasing its taxonomic value as index key to identificate species in the Order Gymnonidial.
Comparison: D. lamarense differs from D. acuminatum Evitt et al, in having fewer ribs (0-6), a strongly antapical horn, an unthickened ridge along the cingulum, a bigger CI mid granulation over apex and antapex. A. euclaense (Cookson & Eisenack)Lentin & Vozzhennikova has not ribs in the "hypotest" and has a different outline. D. digitus has a less notorious granulation than D. lamarense and does not have an antapical horn.
------------------------------------------------------