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Exochosphaeridium gracile
Holotype. Plate 1, figure 19; GSCA slide no. 51297-05 (¼GSCC slide no. P5205–190H); coordinates 6.8x90.5; EF V56/ 2; Nunavut Palaeontology Collection no. NUPB 971; Q section, Twosnout creek, Bylot Island. Bylot Island formation.
Etymology. The epithet is from the Latin gracilis, meaning slender, gracile in reference to the nature of the processes.
Diagnosis. A species of Exochosphaeridium with a slender apical protrusion or process that may be branched along its length or distally, as shown in Plate 1, figures 19 and 20. The general ornamentation consists of slender nontabular processes that are usually expanded distally, furcate or bifid (Plate 1, figures 17 and 18); some of the processes are somewhat broader. The wall is fibrous, the fibres forming a reticulate ornamentation.
Comments. The form identified as Fibrocysta? sp. cf. F. vectensis by Ioannides (1986) is similar to Exochosphaeridium gracile in having furcate or bifid processes. However, Exochosphaeridium gracile differs in the nature of the apical structure, which is essentially an enlarged process, that is commonly branched.
Size. Holotype: overall length 63um, width 48um, central body length 46um, central body width 38um, processes up to 8um, apical process length 12um, apical process width up to 3um. Range of five specimens: pericyst length including apical protuberance 63–87um, pericyst width 48–63um; central body length 46–63um, central body width 38–55um.
Age. Late Maastrichtian to Selandian.
Etymology. The epithet is from the Latin gracilis, meaning slender, gracile in reference to the nature of the processes.
Diagnosis. A species of Exochosphaeridium with a slender apical protrusion or process that may be branched along its length or distally, as shown in Plate 1, figures 19 and 20. The general ornamentation consists of slender nontabular processes that are usually expanded distally, furcate or bifid (Plate 1, figures 17 and 18); some of the processes are somewhat broader. The wall is fibrous, the fibres forming a reticulate ornamentation.
Comments. The form identified as Fibrocysta? sp. cf. F. vectensis by Ioannides (1986) is similar to Exochosphaeridium gracile in having furcate or bifid processes. However, Exochosphaeridium gracile differs in the nature of the apical structure, which is essentially an enlarged process, that is commonly branched.
Size. Holotype: overall length 63um, width 48um, central body length 46um, central body width 38um, processes up to 8um, apical process length 12um, apical process width up to 3um. Range of five specimens: pericyst length including apical protuberance 63–87um, pericyst width 48–63um; central body length 46–63um, central body width 38–55um.
Age. Late Maastrichtian to Selandian.