Clypeomorus admirabilis Houbrick 1985

Clypeomorus admirabilis

DESCRIPTION.—Shell (Figure 47; Table 28): Shell turreted, moderately elongate with teleoconch of 8 or 9 angulate, inflated whorls having an apical angle of 40 degrees. Shell reaching 26.3 mm in length (not on Table 28). Teleoconch whorls have broad subsutural ramp below which are 2 (rarely 3) distinct, thickened, nodose spiral cords. Nodes somewhat spinose, sometimes reduced and blunt, aligned to form about 9 distinct axial ribs per whorl. Entire shell covered with fine microscopic spiral threads and weak, broad, axial ribs that are absent on earliest whorls. Early whorls usually badly eroded, even in immature specimens. Suture distinct, wavy. Body whorl large, angulate, sculptured with 5 or 6 nodose spiral cords and 8 or 9 angulate, axial ribs. Large varix present opposite outer lip and at edge of outer lip of aperture. Ventral side of body whorl flattened and base constricted at siphon. Slight siphonal fasciole present. Aperture ovate, a little less than one-third the shell length. Anterior siphonal canal short, deep, and deflected to left at a 45 degree angle to shell axis. Anal canal distinct, bordered with columellar fold that extends well within shell aperture. Columella concave with moderate parietal callus. Outer lip weakly crenulate, thick, bearing varix. Inner surface of outer lip beveled and with four pairs of spiral plications. Outer lip extends slightly onto penultimate whorl. Plane of outer lip parallel to shell axis. Periostracum thin, yellowish, usually eroded on upper whorls. Shell color white to yellow-tan and usually with spiral bands of brown quadrate spots between nodes. Shell sometimes lacking spots, nodes usually white or light colored. Operculum thin, tan, corneous, ovate and with nucleus near edge. Attachment scar elongate, on lower half of obverse of operculum.

Radula (Figure 48): Radular ribbon long, a little less than one-third the shell length and comprising 126 rows of teeth in shell 25 mm long. Shell length/radula length index 2.8. Rachidian tooth (Figure 48d) pentagonal, about 64 μm wide and as high as wide. Basal plate of rachidian tooth flat, slightly pointed at base; sides straight with thin lateral buttresses on each side. Top of rachidian tooth straight, cutting edge with broad, chisel-shaped, straight-edged central cusp flanked on each side by single blunt tiny denticle. Basal plate of lateral tooth (Figure 48c) has long, twisted, lateral projection that inserts onto radular membrane and large, downward directed median buttress. Cutting edge of lateral tooth has single large, wide, spoon-shaped cusp flanked by a tiny blunt denticle on each side; denticles nearly fused to large central cusp. Lateral extension of basal plate with slight baffle directly adjacent to cutting edge of lateral tooth. Marginal teeth (Figure 48a,b) long, having wide shafts and spatulate curved tips; narrow at bases where inserted onto radular membrane. Tips of marginal teeth with large spoon-shaped cusps having single tiny inner denticles. Outer edges of marginal teeth smooth.

Animal: Not known.

HOLOTYPE.—WAM 3346-83, 24.4 mm length, 11.7 mm width (Figure 47d,f).

PARATYPES.—USNM 784652, 7 specimens; ANSP 233431, 38 specimens; AMS 139779, 3 specimens.

TYPE-LOCALITY.—In sand and rock, 182 meters up False Cape Creek, 100 mi (161 km) S of Broome, Western Australia, 16 Sep 1958, Virginia Orr, coll.

ETYMOLOGY.—From the Latin adjective admirabilis, -e (wonderful, admirable), referring to the beautiful sculpture and color.

ECOLOGY.—There is virtually no ecological data accompanying museum specimens of this species. Field records from the Broome area indicate that Clypeomorus admirabilis lives on sandy rubble in intertidal flats near mangroves, on muddy flats around Buccaneer Rock, and at the mouth of tidal creeks. This kind of intertidal habitat is typical for most Clypeomorus species. Eggs and larvae are unknown, but the limited geographic range suggests lecithotrophic development.

The spoon-shaped cusps on the lateral and marginal teeth may indicate a scraping, shoveling function on soft substrate.

Clypeomorus admirabilis is a species of sea snail, a marine gastropod mollusk in the family Cerithiidae.