Gouldipoma thomasi ( Solem, 1961 )

Watters, G. Thomas, 2014, A revision of the Annulariidae of Central America (Gastropoda: Littorinoidea), Zootaxa 3878 (4), pp. 301-350 : 325-326

Gouldipoma thomasi ( Solem, 1961)

Figure 6 T– Y, 12 C

Type material. FMNH 73390, holotype (figs. 6 T, U); FMNH 98193 (1), paratype; MCZ 111175, “other paratypes.”

Type locality. “ the Natural Bridge [Arco Rocoso] of the Rio Puente near the shore of Madden Lake [Alajuela Lake], Canal Zone, Panama.”

Type figured. Solem, 1961: pl. 11, fig. 23.

Chresonymy.

Tudora (Tudorata) thomasi Solem, 1961: 208 –209, pl. 11, fig. 23, pl. 12, fig. 24s, map 2; Watters, 2006: 508; Thompson, 2011: 45, 283.

Gouldipoma thomasi ( Solem, 1961) . Watters, 2006: 72, 508.

Distribution and habitat. This rarely seen Panamanian species has been collected in the extreme eastern end of the Serranía de San Blas in the vicinity of Alajuela Lake and in the Serranía de Maja south of Lago Bayano. Most specimens were associated with caves.

Other material (specimens examined=3). Panamá: Panamá Province: GTW 9121a (1), S of Lago Bayano; GTW 9121b (1), Sal Si Puedes Cave S of Lago Bayano; GTW 9121c (1), Pueblo Nuevo S of Lago Bayano.

Description. Shell high spired, thin, translucent, last whorl solute just before aperture. Smallest adult specimen seen 15.0 mm in length, largest 18.1 mm, average 17.0 mm (non-decollate). Protoconch retained in all adults seen, 1.5–1.75 prominent, rounded, flat-topped dark brown, almost black, whorls; poorly demarcated from teleoconch. Teleoconch of 5 rounded whorls. Umbilicus open, not occluded by outer lip. Spiral sculpture absent except for two weak cords delimiting the umbilicus. Axial sculpture of ca. 90–100 closely spaced, flattened threads. Suture indented, not channeled. Tufts absent but the axial lamellae may render the suture minutely serrate. Aperture nearly circular. Inner lip not exserted, fused with outer lip. Outer lip very narrow, narrowest facing umbilicus, narrowly auriculate posteriorly, solute from previous whorl. Color uniformly greenish-gray; first teleoconch whorls dark brown like protoconch, very faint spiral rows of tan spots on early spire whorls; umbilicus with dark purplish brown band that continues onto the outer lip. Last 1/8th whorl and aperture blushed with pinkish orange. Operculum multispiral with remains of a calcareous lamella, which is often worn away. Radula and anatomy unknown.

Variation in specimens. The few specimens seen are uniform in all characteristics.

Comparison with other species. The near lack of spiral sculpture and the presence of a dark protoconch and dark umbilicus are unique among Central American annulariids.

Remarks. This obscure species is 100s of km away from the next known annulariids. The geographically closest relatives are the Colombian Halotudora magnifica ( Solem, 1960) and Gouldipoma woodringi ( Solem, 1960) , both over 250 km away. The similar Gouldipoma callipeplum ( Solem, 1961) is 750 km to the northwest in Nicaragua.

Original description. “Shell elongate-conic, spire increasing regularly in breath, whorls 6 3/8 to 6 7/ 8 in undecollated adults (5 ½ remaining in holotype), moderately rounded with impressed sutures. Apical whorls 2 ½, smooth, dark purple. Decollated examples with purple plug, very gradually slanted and running almost one-half whorl. Lower whorls with sculpture of slightly retractive radial ribs that become lamellate below the suture and whose interstices are about three times their width. Body whorl appressed or slightly solute (less than 1 mm.). Umbilicus open, with only one or two strong spiral cords. Aperture with only slightly expanded lip, very similar to that of R. plicatula. Columella with a purple marginal band. Spire with three faint spiral bands of dots. Operculum with slightly acentral nucleus. In only specimen seen (holotype), there are remnants of vertical calcareous ridges indicating that calcareous plates have been eroded. Height of holotype 16.7 mm., minor diameter 7.5 mm., whorls remaining 5 ½.”

Etymology. W. Donald Thomas, collector of the types.

Figures

FIGURE 6 A – F. Gouldipoma callipeplum (Solem, 1961). A. FMNH 90603, paratype, 12.3 mm, photo courtesy of J. Gerber (FMNH). B – F. UINHM 25952, paratypes. B – C. 11.6 mm. D. 12.1 mm. E – F. 14.2 mm. FIGURE 6 G – S. Gouldipoma chrysostiria new species. G – H. UF 479667, holotype, 14.3 mm. I. UF 479667, paratype, 13.6 mm. J. UF 221351, 16.5 mm. K. UF 221412, 11.3 mm. L. UF 221412, 15.9 mm. M. UF 221164, 11.1 mm. N. UF 221164, 15.6 mm. O. UF 221391, 15.5 mm. P. UF 221391, 14.7 mm. Q. UF 221326, 15.1 mm. R. UF 211969, 13.2 mm. S. UF 212016, 14.0 mm. FIGURE 6 T – Y. Gouldipoma thomasi (Solem, 1961). T – U. FMNH 93390, holotype, 17.7 mm, photo courtesy of J. Gerber (FMNH). V – W. GTW 9121 a, 15.0 mm. X – Y. GTW 9121 b, 17.8 mm.