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Cycladophora cosma irregularis
Lombari and Lazarus, 1988
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Description - Add description
Description: Cephalis is simple, of medium size, subspherical with numerous subcireular pores and two thornless, bladed apical horns; horns arc 1-2 times the diameter of the cephalis. Cephalis is slightly depressed into the upper thorax, forming a weak spinal furrow. Lateral spines may be expressed externally. Upper thorax is compressed, weakly flared and fairly flat in outline with subcireular, non-uniform pores. Pores may have a thin interior lattice. They arc small though non- uniform in size and are arranged in staggered horizontal rows. However, in some specimens pores are irregularly arranged. Pore bars are of medium width and thickness and they arc free of spines, costae and sponge. Most specimens do not exhibit a pore size gradient. Upper thorax suture is unconstricted. Lower thorax is elongate, moderately flared and flat in outline. Pores arc irregular in shape, medium to large in size, and arranged in staggered horizontal rows, although some specimens may appear to have pores irregularly arranged due to differences in pore size. A gradual, strong pore size gradient increases distally. Pores are open with narrow pore bars of medium thickness which are free of ornamentation. The first few rows of lower thorax pores may have a thin interior lattice. Lower thoracic suture is unconstricted. Complete specimens do not appear to possess an abdomen. There is one row of short basal spines. No basal plate is observed.
Type: DSDP Site 173, core 28, section 2, 44 cm. England finder number T29/2.
Origin of name: From the Latin irregularis, not regular. Named for the irregular pores in the lower thorax.
Comments: Cycladophora c. irregularis is similar to C. c. cosma in size and shape and in the possession of pores with interior lattice. However, C. c. irregularis differs from most other cycladophorids in the high degree of irregularity in the size and shape of its lower thoracic pores. In some specimens the upper lower thoracic pore rows tend to be more regular than the lower rows.
Occurrence: Found in DSDP Site 173-29-2, 41 cm through 173-12-CC, DSDP Site 116-13-CC, DSDP Site 278-29-CC through 278-26-CC. It is generally not found in large abundances. | | Lombari & Lazarus 1988 |
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