Halotudora gaigei ( Bequaert & Clench, 1931 )

Watters, G. Thomas, 2014, A revision of the Annulariidae of Central America (Gastropoda: Littorinoidea), Zootaxa 3878 (4), pp. 301-350 : 309-310

Halotudora gaigei ( Bequaert & Clench, 1931)

Figures 2 A–K , 12 B

Type material. UMMZ 49190, holotype (fig. 2 A); MCZ 79390 (1), paratype; MCZ 79783 (1), paratype.

Type locality. “ Chichin Itzá, Yucatan.”

Type figured. Bequaert & Clench, 1933: text fig. 26, pl. 68, figs. 8–11.

Chresonymy.

Choanopoma gaigei Bequaert & Clench, 1931: 425 –426; Bequaert & Clench, 1933: 540 –542, text fig. 26, pl. 68, figs. 8–11; Goodrich & van der Schalie, 1937: 12, 15, 22, 32; Harry, 1950: 7, 26–28; Branson & McCoy, 1963: 104; Thompson, 1966: 27, 28; Thompson, 1967: 225, 227; Watters, 2006: 269.

Choanopoma (Choanopomops) gaigei Bequaert & Clench, 1931 . Bequaert & Clench, 1936: 72; Solem, 1961: 197, 203, pl. 10, fig. 5, pl. 12, fig. 24e, map 1; Thompson, 2011: 46, 280, 284, 291, 296.

Choanopoma gagei [sic] Bequaert & Clench, 1931. Richards, 1937: 257.

Halotudora gaigei ( Bequaert & Clench, 1931) . Watters, 2006: 73, 269.

Distribution and habitat. Yucatán Peninsula of Campeche, Quintana Roo, and Yucatán states in México, in Belize, and into Izabal Department of Guatemala. Snails occur on lowland limestone outcrops and in cenotes. Often encountered at the Mayan ruins of Chichén-Itzá, Chetumal, Kohunlich, and others.

Conservation. A significant portion of the range occurs in reserves, parks, and archeological sites in both Belize and México.

Other material (specimens examined: 201). México. Campeche State: UF 19093 (4), 9.2 km E of Campeche; UF 19088 (17), UF 213712 (10), 6.4 km E of Xpujil; UF 155822 (4), Becán; UF 19080 (17), 5.8 km S of Hopelchén; UF 19087 (11), 30.9 km E of Silvituc; UF 19091 (10), 8.2 km W of Tikimul; UF 19090 (3), 5.5 km S of Cayal; UF 19098 (2), 3.5 km S of San Pablo Pixtún. Quintana Roo State: GTW 13725a (1), Chetumal; UF 133597 (11), 30.0 km S of Felipe Carrillo Puerto; GTW 13725c (1), UF 155826 (5), Kohunlich; UF 19084 (1), 9.7 km N of Dzibanche; UF 19092 (5), 3.7 km SSE of Polyuc; UF 19089 (3), 10.4 km NNW of Polyuc. Yucatán State: GTW 13725b (2), UF 275359 (3), Chichén-Itzá; UF 19085 (11), 1.3 km NE of Becanchén. Belize. Orange Walk District: UF 207140 (30), UF 207164 (33), 1.0 km E of Neuendorf, 100 m; UF 207181 (1), UF 207182 (8), 5.4 km W of Neuendorf. Cayo District: GTW 13742c (1), Río Frío Cave. Stann Creek District: UF 207591 (1), mogote 2.2 km S of Trio Village, 50 m. Guatemala. Izabal Department: UF 19152 (6), 4 km N of Morales.

Description. Shell conical, moderately high-spired, thin but solid. Smallest adult specimen seen 10.6 mm in length, largest 18.2 mm, average 14.6 mm (non-decollate). Protoconch usually retained in adult, 1.5 prominent, rounded, pale whorls. Teleoconch of 4.5–5 rounded whorls. Umbilicus wide, partially occluded by outer lip. Spiral sculpture of numerous faint, low cords, separated by about twice their width, much stronger in the umbilicus. Axial sculpture of numerous fine lines that render the shell minutely decussate; this sculpture is more lamellate and widely separated on earlier whorls. Suture strongly indented, narrowly channeled in some specimens. Tufts absent but groups of axial lamella may be somewhat wider at the suture rendering the suture finely serrate. Aperture nearly circular. Inner lip smooth, narrowly exserted. Outer lip strongly lamellate, widely to moderately reflected perpendicular to whorl, evenly expanded, usually auriculate posteriorly, narrowly solute or (less commonly) scarcely attached to previous whorl. Base color dingy white to yellowish-tan, first teleoconch whorl darker in some specimens. Rarely unicolor, usually with spiral, more or less continuous brown bands, occasionally broken into spots, bands lacking in umbilicus. Outer lip white; the bands do not extend to the front of the peristome. Inside of aperture brownish-orange or white with the outer pattern showing through. Operculum paucispiral, with a thick reflected plate composed of numerous recurved lamellae. Radula and anatomy unknown.

Variation in specimens. The color pattern varies from all white to strongly patterned.

Comparison with other species. This species differs from H. kuesteri and H. gruneri in the retention of the protoconch (usually) and in the narrowly solute outer lip. It lacks the fused tufts of C. largillierti . From P. cordovanus and P. rubicundus it differs in the heavily calcified opercular plate.

Remarks. It is peculiar that this widespread and distinctive species, commonly occurring at oft-visited Mayan ruins, should have remained undescribed until 1931, particularly since it is one of the most widely distributed of all the Annulariidae (the Venezuelan Gouldipoma plicatulum ( Pfeiffer, 1846) appears to hold the distinction of having the broadest zoogeographic range of the family).

Original description. “Medium in size, acuminate, elongate-conic, narrowly umbilicate. Color pale brown, with spiral bands of mahogany red, the bands usually irregularly broken, more strongly developed on the last two whorls. Whorls 6, convex, regularly increasing in size, and often all preserved in adult specimens; sometimes only the embryonic whorls lost. Spire acute, but the apex truncate, the first whorl being depressed. Aperture entire and nearly circular. Peristome duplex: inner rim sharp and circular; outer rim reflected, somewhat wavy, and forming a slight rounded expansion near the parietal angle. Sutures deep, not channeled, strongly but finely and regularly beaded. Sculpture of both axial and spiral threads. Embryonic whorls smooth; third and fourth whorls with strong, axial riblets, regularly spaced. On the remaining whorls the spiral sculpture gradually approaches and eventually equals the axial riblets, which on the last whorl are more crowded. Under the lens the last whorl is finely reticulate. The fine sutural beading is caused by the insertion and slight thickening of the axial riblets. Operculum calcified, paucispiral, circular, composed of three whorls; occasionally the edge irregularly crenulate; the last whorl rapidly increasing in size, being equal in width to the other two whorls together; the lamella only slightly elevated and not extending over the spiral suture; nucleus strongly eccentric.”

Etymology. Frederick McMahon Gaige (1890–1976), entomologist at the University of Michigan, who collected the holotype.

Figures

FIGURE 2 A – K. Halotudora gaigei (Bequaert & Clench, 1931). A. UMMZ 49190, holotype, 14.5 mm. B – C. UF 19088, 15.2 mm. D. UF 155822, 13.4 mm. E. UF 133597, 16.6 mm. F. UF 19092, 15.7 mm. G. UF 19152, 13.5 mm. H. GTW 13724 c, 15.6 mm. I. GTW 13725 b, 14.0 mm [operculum glued in aperture backward by collector]. J. GTW 13725 b, 13.2 mm. K. GTW 13725 a, 16.1 mm.

FIGURE 12 A – D. Distribution maps. A. Choanopomops largillierti (Pfeiffer, 1846) (black); Parachondria rubicundus (Morelet, 1849) (red); Parachondria cordovanus Pfeiffer, 1857 (blue); Paridoxipoma enigmaticum new species (white). B. Halotudora sumichrasti (Crosse & Fischer, 1874) (blue); Halotudora gaigei (Bequaert & Clench, 1931) (black); Diplopoma osberti (Tristram, 1861) (red); Halotudora gruneri (Pfeiffer, 1846) (white). C. Gouldipoma chiapasense (Crosse & Fischer, 1877) (red); Diplopoma rigidulum (Morelet, 1851) (black); Tudorisca andrewsae (Ancey, 1886) (blue); Gouldipoma coltrorum new species (white); Gouldipoma thomasi (Solem, 1961) (purple). D. Gouldipoma trochlearis (Pfeiffer, 1852) (red); Halotudora kuesteri (Pfeiffer, 1852) (black); Gouldipoma terecostatum (Thompson, 1966) (blue); Gouldipoma chrysostiria new species (purple); Gouldipoma callipeplum (Solem, 1961) (white).