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Pterocanium grandiporus Nigrini, 1968

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Description: Similar in size and shape to P. trilobum Nigrini (in press), but shell maybe heavier and rougher, cephalic pores better defined, and apical horn usually longer. Thoracic pores larger than those of P. trilobum. 9-11 across the widest part of the segment.
Abdomen often quite well developed and attached to the feet for at least most of its length. Pores large, subcircular, having no definite arrangement; those adjacent to the feet larger than the others. Termination always ragged.
Dimensions: Length of apical horn 45-81 μ. of cephalis 14-27 μ. of thorax 63-90 μ. of feet 108-240 μ. Maximum breadth of cephalis 23-27 μ. of thorax 90-1 27 μ.
Occurrence: Few in 2 samples near the coast of Central America and in 2 equatorial samples near the coast of South America, rare or absent in all other samples examined (text-figure 8).
Figured specimen (holotype) from RIS 11G. 0-4 cm., USNM No. 650032.
Remarks: This species is distinguished from other members of the genus Pterocanium by its large thoracic and abdominal pores, and for that reason is named grandiporus.
Nigrini 1968











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