Antillipecten guanicus (Maury, 1920)
MAURY, C. J. 1920. Tertiary Mollusca from Porto Rico. In Scientific Survey of Porto Rico and the Virgin Islands, 3 (1): 1-77, pls. 1-9. New York Academy of Sciences, New York. [p. 18, pl. 4, fig. 4]
1920 Pecten guanicus Maury, 1920
C. J. Maury, 1920, plate 4.
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«Shell rather small, obliquely fan-shaped; right valve with about nineteen ribs. On the upper part of the valve towards the beaks, the ribs are carinated by a single radial thread and the narrow interspaces are smooth. Somewhat further down the single radial thread on each rib becomes accompanied by a second, this by athird and a fourth. About the same time that the tertiary radials appear on the ribs one or two radials develop on the interspaces. Hence on the ventral margin of the shell each rib is ornamented with four radial threads and each interspace with two. Anteriorly the ribs tend to become flatter than on the posterior part of the valve. Approximate altitude 24 mm., breadth 26 mm. The single specimen is partly concealed by the matrix but the characteristics of sculpture are well preserved.
In general form and in the sudden development of more ornate sculpture this species resembles Pecten hatoviejonis Maury from the trail between Hato Viejo and Potrero, Santo Domingo, but that shell is decidedly squamose whereas this is entirely without scales. Brown's [Proc. Acad. Nat. Sci. Phil., 1913, PI. XVIII] figure 6 of Pecten anguillensis Guppy bears a slight resemblance to the Porto Rican shell, but his figures 4, 7, 8 of P. anguillensis are quite unlike our specimen. The Antigua shell like ours has secondary ribbing but the ribs are far broader and much less numerous. The Porto Rican shell is decidedly more like the Dominican species. Dr. Dall has examined this Pecten and he notes that the National Museum has it from Santo Domingo but not named. Locality.— East shore Guanica Harbor, Station 369.» CARLOTTA JOAQUINA MAURY, 1920
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