| Calliotropis nomismasimilis | |
|---|---|
 | |
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Mollusca |
| Class: | Gastropoda |
| Subclass: | Vetigastropoda |
| Family: | Calliotropidae |
| Genus: | Calliotropis |
| Species: | C. nomismasimilis |
| Binomial name | |
| Calliotropis nomismasimilis Vilvens, 2007 | |
Calliotropis nomismasimilis is a species of sea snail, a marine gastropod mollusk in the family Eucyclidae. [1]
The size of the shell varies between 4 mm and 8 mm.
 | This section needs expansion. You can help by adding to it. (April 2013) |
The shell of the Calliotropis nomismasimilis is small for the genus, up to 5.2 mm in height and 9.1 mm in width, much broader than high and cyrtoconoidal (approaching a cone in shape, but with convex sides) [2] . [1] The spire is depressed, its height about 0.5–0.6× the shell width (≈4.1- 4.7× the aperture height). [1] The umbilicus is broad. [1]
The protoconch is 280–300 µm, of one whorl, without a terminal varix. [1] The teleoconch has up to 4.8 whorls: early whorls are moderately convex and later whorls slightly concave. [1] Two granular spiral cords are present on the first whorls and three on the last whorls. [1] Primary axial sculpture occurs only on the first whorls. The suture is deeply grooved longitudinally. [1]
First teleoconch whorl: about 20 slightly prosocline smooth ribs with interspaces 2-2.5× rib width; granular cords P1 and P3 appear almost immediately, with nodules at rib intersections; P3 is slightly stronger. [1]
Second whorl: beads on both cords become stronger and sharper, thicker on P3; axial ribs weaken. [1]
Third whorl: beads of P1 and P3 broaden and are bluntly sharp; spacing between beads ≈2× bead size; P4 emerges from the suture mid-whorl, lamellose, with scaly beads that are smaller and about six times more numerous than P3 nodules; P2 is absent; axial ribs disappear. [1]
Fourth whorl: P1 beads are nearly vertical; P4 fully emerges, leaving no gap with P3; P4 beads are smaller than P1, bluntly sharp, scaly. [1]
Last whorl: P4 becomes peripheral and forms a keel; its beads are vertically elongated and about three times more numerous than P3 nodules; two, sometimes three, granular tertiary cords appear after mid-whorl between P1 and P3. [1]
The aperture is imperfectly quadrangular. [1] The outer lip is thin with a submedian angle aligned with external P3–P4 and meets the inner lip at about 120°. [1] The columella is oblique, curved in its anterior third, bears one basal tooth, and expands into the umbilicus. [1] The base is moderately convex with an outer smooth zone and six closely spaced granular spiral cords; spacing is about half a cord’s width. [1] The innermost cord is strongest and borders the umbilicus; stout axial ribs connect the beads of the cords. [1] The umbilicus is wide (≈30% of shell width), deep, and tunnel-shaped, with steep walls, crowded weak axial riblets, and no internal spiral cord. The teleoconch and protoconch are hazel-beige in colour. [1]
This species occurs in the Pacific Ocean off the Solomon Islands.
Media related to Calliotropis nomismasimilis at Wikimedia Commons