Anatoma plicatazona, Geiger, Daniel L. & Mclean, James H., 2010

Geiger, Daniel L. & Mclean, James H., 2010, New species and records of Scissurellidae and Anatomidae from the Americas (Mollusca: Gastropoda: Vetigastropoda), Zootaxa 2356, pp. 1-35 : 20-22

Anatoma plicatazona n. sp.

Figure 15

Anatoma n. sp.: Geiger, 2008: fig. 1.

Type material. Holotype ( SBMNH 83518, ex. CRC 12843). Paratype ( BMSM 17981, ex CRC 12842) from type locality.

Type localit y. 7 m, Sandy Cay, Abaco, Bahamas, 26.399˚N, 76.988˚W. August 13, 2005, leg. Colin Redfern.

Etymology. Plicata, Latin for folded, -zona referring to the selenizone. Describing the diagnosing feature of the strongly upward folded selenizone.

Description. Shell to 1.5 mm, trochiform, turreted. Protoconch 0.75 whorls, flocculent sculpture, no apertural varix, apertural margin straight. TI of 0.25–0.33 whorls, 11–12 axial cords, no spiral sculpture, interstices with irregularities. TII> 2 whorls. Shoulder convex, approximately 50 distinct axial cords on first whorl, becoming gradually less distinct to diffuse towards apertural margin; first spiral after 0.125–0.25 TII whorls, half to third strength of axials, increasing to 5–7 after 1 TII whorl, of equal strength as axials, forming raised points at intersection with axials; raised points best developed after 1.25 TII whorls; sculpture becoming less distinct with growth, forming subdued cancellate pattern. Suture little impressed, position descending with growth from 1.5 width of selenizone below selenizone, to mid base (~3 selenizone widths below selenizone). Base convex, evenly curving into umbilicus, barely constricted below selenizone; sculpture becoming weaker with growth and from selenizone towards base; reticulate sculpture with raised points at intersection below selenizone, subsequently approximately 13 low spiral steps. Aperture rounded, adumbilical portion of peristome flared. Selenizone slightly above periphery; keels of moderate strength, broken in early portion of whorl, appearing to have horizontal orientation, on last 0.5–0.66 whorls orientation of keels parallel to coiling axis; slit open, margins parallel. Animal unknown.

Differential diagnosis. Anatoma aedonia Watson, 1886 , from the Caribbean has a similar overall shape and similar protoconch. However, TI is of 1 whorl and has a distinct spiral cord in the position of the selenizone, the sculpture on TII remains the same throughout growth, with distinct axial cords, and very fine spiral lines, and the axial sculpture on the base extends to the umbilicus. Differential diagnosis based on examination of types in BMNH and NMW by SEM.

Distribution. Known only from type locality.

Figures

FIGURE 15. Anatoma plicatazona n. sp., 7 m, Sandy Cay, Abaco, Bahamas, 26.399 ˚ N, 76.988 ˚ W, leg. Colin Redfern. A. Holotype SBMNH 83518. B. Paratype BMSM 17981. Scale bar shell = 1 mm. Scale bars protoconch = 100 µm.