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Larcopyle bütschlii Dreyer

Larcopyle bütschlii Dreyer, 1889, p. 124, pl. 10, fig. 70; Benson, 1966, p. 280, pl. 19, figs. 3-5

DESCRIPTION "Large ellipsoidal shell when fully developed with regular outline; surface with scattered short (5-25 microns) conical spines or thorns continuous inward as beams; pores unequal, irregular, larger than those of preceding species; at one pole in a few specimens a cluster of short (5-12 microns) conical spines but without definite opening or pylome. Internal structure consists of irregular but generally recognizable latticed lamellae joined by numerous radial beams, in several specimens with an identifiable pylonid structure of concentric trizonal shells or spirals, particularly apparent in those with outer shell not fully developed. Those specimens with a recognizable internal triangular pylodiscid shell were placed within Discopyle ? sp." (from Benson, 1966).

DIMENSIONS "based on 30 specimens...major diameter of test 135-246 microns, minor diameter 81-172 microns; length of axes of internal trizonal shells (8 specimens): P1 18-33 microns, P2 59-95 microns, T1 14-18 microns, T2 39-74 microns." (from Benson, 1966).

REMARKS

1. Benson (1966, p. 279) also described a similar form, Larcopyle sp., which may be distinguished from L. bütschlii "by its relatively smaller size, its smooth surface without radial spines, and the presence of secondary pores filling the spaces of the large pores of the outer shell." Moore (personal communication) noted that the smaller form is more abundant, but he counted it together with the larger form.

Plate 17, figures 1a,b

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RECENT DISTRIBUTION

1. Benson, 1966; "rare but cosmopolitan in the Gulf [of California]... its distribution in local areas may be favored by upwelling."

2. Sachs, 1973, fig. 2D, Code 30I; the dimensions given by Sachs suggest that he was counting Larcopyle sp., not L. bütschlii; "This form is rather strongly southern in its preferences, loading on the transitional factor. With the exception of an anomalous occurrence (9%) in sample 026, which may be a counting error, the maximum abundance is less than 5% in the surface study. The form is encountered in almost all sample south of 43 degrees N."

3. Morley, 1977, fig. I-20; "This species loads highest in factor 3 (gyre margin). At present it is most frequently found in samples from the subantarctic region. Although the abundance of this species decreases at 18,000 YBP, the region of maximum concentration is comparable to that for the present-day."