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Lithopera renzae Sanfilippo and Riedel, 1970

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Lithopera (Lithopera) renzae
Description: Subellipsoidal shell, of which the thorax forms the major part. Cephalis spherical, usually with small circular pores, half or more of it enclosed in the thoracic wall, with a small apical horn. Collar stricture not usually pronounced externally. From the base of the cephalis, primary lateral and dorsal spines extend in the thoracic wall or within the thoracic cavity to join the inner surface of the upper wall. Remainder of shell subellipsoidal, with pores very irregular in size and arrangement, tending to form a spongy meshwork especially in the upper part of the thorax. In some specimens the thoracic wall is not actually spongy, but the pores are divided by secondary bars. Inverted-hemispherical or inverted-conical abdomen usually separated from the larger thorax by a distinct stricture and change in contour.
Measurements: Based on 30 specimens from cores AMPH 6P, 18-20 cm. and 52-54 cm.; DODO 39P, 182-184 cm. and 323-325 cm.; and SDSE 76, 1228-1229 cm. Total length (excluding horn) 100-165. Maximum breadth 80-110. Ratio of length of abdomen to length of thorax (measured from base of cephalis) (0.01 -1.3): 1, usually (0.3-0.7): 1.
Remarks: L. renzae is distinguished from L. baueri by its less spongy meshwork. smaller size, and a lumbar stricture usually accompanied by a change in contour. It is distinguished from L. neotera as indicated under that species, and from Stichocorys diploconus by having a spongy wall and only three segments.
This species is named for Miss G. W. Renz, a student of polycystine radiolarians who contributed to the early phase of the research leading to this paper.
Sanfilippo and Riedel 1970


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