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Clathromitra pterophormis
Haeckel, 1887
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Description - Add description
Benson, 1966, p. 399-400; pl. 26, fig. 4:
Clathromitra pterophormis Haeckel
Clathromitra pterophormis Haeckel, 1887, Challenger Rept., Zool, vol. 18, p. 1219, Pl. 57, fig. 8.
Test consisting of a single, very large, conical joint corresponding to the cephalis. Surface of test rough; lattice very irregular; an irregular double layer resembling a spongy structure, distally (not unlike the double cortical shell of Diploplegma banzare Riedel); proximally without outer 1ayer of lattice but with irregular, unequal pores. Apical bar a centrally located, cylindrical columella with one or two verticils of three branches which join with the inner surface of the test; median bar in the plane of or slightly above the wide, circular mouth of the test; dorsal, primary lateral, and vertical bars cylindrical, long (85-110 µm), all but the last with a verticil of two branches which join with the inner surface of the test. The dorsal and primary lateral bars pierce the shell wall terminally or subterminally and extend outward but downward as heavy, three-bladed feet. The vertical bar extends as a heavy, three-bladed, ventrally ascending, vertical horn. The apical bar extends as a similar, three-bladed apical horn, the blades of which are extended laterally as three irregular keels, each joining with one of the basal feet and pierced with numerous, unequal, irregular pores.
Measurements; based on 4 specimens from stations 27, 56, and 106: maximum length of test (one specimen) 332 µm, maximum breadth 234-277 µm; length of apical horn 86 µm, of vertical horn 43 µm; of feet 25-49 µm.
Remarks. This species is similar to Haeckel'a illustration (1887, Pl. 57, fig. 8) of Clathromitra pterophormis Haeckel but differs from it in the presence of the double, spongy shell wall. Haeckel's species is much smaller, but because this species is rare in the Gulf, its complete range of variation was not determined.
Due to the large size of this species, specimens in permanent slides generally are oriented with their mouths downward; therefore, only apical views of this species are available. One specimen from station 106 was studied in a wet slide. The description given above is based for the most part on this single test, but it was impossible to photograph it. Haeckel 's illustration of the right lateral side is very similar to this specimen and may be referred to in conjunction with the above description.
Distribution. This species is very rare in the Gulf. It was observed only at stations 27, 34, 46, 56, 60, and 106. It is, therefore, an oceanic species without great affinity for the waters of the Gulf. Its only other known occurrence is from “Challenger” station 265 in the central Pacific (Haeckel, 1887, p. 1219).
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