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Dictyophimus mawsoni Riedel, 1958

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Shell large, of heavy construction, spiy, generally subhemispherical in form. Cephalis cap-like, with subcircular pores and short, acute, thorn-like spines scattered over its surface. Apical horn stout, cylindro-conical, vertical or oblique. Collar stricture indistinct. Thorax subhemispherical, with large subcircular or subangular pores seperated by heavy intervening bars from which arise numerous acute, conical spines. Three ribs, which in some specimens are not distinct, extend along the entire length of the thoracic wall and terminate in three sub-parallel or divergent, stout, cyclindroconical feet. At the collar region, three spines extend inward from the shell-wall, but do not connect with each other; these apparently represent all that remains of the reduced internal spicular skeleton. Length of apical horn 113-166µ, of cephalis 33-40µ, of thorax 125-175µ, of feet 100-187µ. Breadth of cephalis 53-76µ, of thorax 196-225µ.
Description based on one specimen from Sta. 94 and one from Sta. 97.
Type locality Sta. 94.
This species is distinguished from all others of the genus Dictyophimus by the combination of characters: heavy construction, spiny surface, long and stout apical horn, and subhemispherical thorax. Although the number of observed specimens is less than that desirable for the description of a new species, the naming of this species seems justifiable because of the apparent constancy of the skeletal structure, and the distinct differences between this and other discribed species.
Riedel 1958











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