Late Pliocene to Late Pleistocene; Recent.
Southern Florida to South Carolina.
For information on the modern distribution of the species, see Malacolog.
First Full Description (from Reeve, 1845, p. 24-25):
"Shell pear-shaped, sometimes oblong, sometimes shorter and ventricose; whorls bi-angulated at the upper part, transversely ridged and striated, ridges minute, narrow, rather superficial; six- or seven-varicose, varices armed with frondlike spines throughout, spines canaliculated, slightly curved, the basal and those upon the posterior angles, longer, sharp-pointed; white, ridges reddish brown, stained here and there with small crescent-shaped spots of a deeper colour, interior of the aperture white, stained in places with ruddy spots; canal rather elongated, sometimes shorter, recurved.
Valenciennes, Kiener, Icon. Coq. viv. p. 49. pl. 41. f. 1. Hab. Gulf of Mexico.
This very interesting shell, of which a worn stunted example is represented in the 'Conchological Illustrations,' fig. 30, under the erroneous title of Murex turbinatus, was, I believe, originally distinguished by Mr. Sowerby by the name of Murex fulvescens; no description, however, appeared, and as the name was subsequently cancelled from the catalogue, I am obliged to yield to M. Valenciennes the honour of having first introduced the species.
The frond-like spines of the Murex spinicostata are of a sharp simple structure, exhibiting no indication of being foliated; but are singularly characterised in being armed with a small prickle on each side at about one-third of their entire length from the top. This character can, however, only be recognised in such specimens as have the spines well developed."
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