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Corythospyris jubata Goll, 1978

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Corythospyris jubata
Diagnosis: A species of Corythospyris characterized by irregularly protruding lattice spines and massive sulcate basal spines. Name: jubatus (Latin)Śhaving a mane.
Description: Sagittal ring subcircular, somewhat D-shaped (Plate 4, Figure 17); 48 to 57 Ám high; 35 to 45 Ám thick; joined directly to front, apex, and back of lattice shell. Vertical spine very short, obscure, arises low on the sagittal ring (Plate 4, Figures 2 and 8). Simple apical spine slender, 18 to 30 Ám long, projects above lattice shell (Plate 4, Figure 7). Prominent axobate visible by bright field illumination (Plate 4, Figures 9 and 16). Frontal bar, primary and secondary lateral bars joined to basal ring.
Basal ring oval, not constricted sagittally; 46 to 63 Ám wide; 38 to 44 Ám thick; joined to frontal bar and directly to back of sagittal ring; and encloses three pairs of basal pores. Smallest pair of basal pores (secondary lateral pores) at front of basal ring, framed by frontal bar and secondary lateral bars, most clearly visible in front view (Plate 4, Figure 11). Lattice shell 53 to 70 Ám high, 76 to 95 Ám wide, slightly constricted by sagittal ring, and does not extend below sagittal ring. Development of lattice shell somewhat variable. Some specimens have a plate of lattice protruding from the front of the lattice shell and joined to the distal end of the basal spine (Plate 4, Figure 1). This extension is absent on other individuals (Plate 4, Figure 10). Three basal lattice spines are massive, circular in cross-section, 35 to 44 Ám long, of approximately equal length, irregularly sulcate distally, project obliquely from the basal ring at the positions of the frontal and primary lateral bars (Plate 4, Figures 7, 10, and 13). Short spines project from lateral surfaces of lattice shell in a chaotic manner. Lattice bars are massive, slightly tuberculate, frame subcircular lattice pores 3 to 25 Ám in diameter. Lattice pores are densely spaced but irregularly arranged, except for the six pairs of sagittal lattice pores, which are larger and occupy fixed positions. Lattice bars joined to basal ring display little uniformity, but lattice bars never occur adjacent to the secondary lateral bars.
Holotype: Plate 4, Figures 14-18 [sic]; locality: 338-13-1, 145-147 cm; repository: U.S. National Museum, Washington, D.C.
Remarks: Corythospyris jubata appears to be the precursor to Corythospyris fiscella and younger members of this lineage. The massive spinous development of the lattice shell easily distinguishes C. jubata from all other Corythospyris taxa, including the type species, C. damaecornis Haeckel, 1887. The ancestry of C. jubata is uncertain.
Occurrence: Corythospyris jubata has not been observed in siliceous sediments of equivalent age from other localities. This species is referred to as Trissocyclidae sp. A on the stratigraphic range chart of Bjorklund (this volume, Table 24). However, the definition of C. jubata differs slightly from the concept used by Bjorklund, and C. jubata has been observed in somewhat younger sediments. At Site 338, C. jubata has a common and continuous occurrence from Sections 10-2 to 19-3 as well as scarce, sporatic occurrences in Sections 21-1, 22-4, and 23-3. These oldest scarce occurrences may be the result of reworking. Conversely, these occurrences may indicate that the Norwegian Sea was peripheral to the province of C. jubata during its early history (Phorticium sp. A Zone to Ceratocyrtis robustus Zone). During the late Oligocene (Velicucullus oddgurneri Zone), both C. jubata and its descentant species C.fiscella migrated into the Norwegian Sea, where they subsequently maintained continuous populations until middle Miocene time. Corythospyris jubata disappears in Section 10-2.
Goll 1978











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