. turriculata-group, the composition of Tesch's species groups has changed by species invalidations, the addition of new species over time, and addition of three new species groups. The main changes in Tesch's species groups have occurred in the A. peronii-group (with A. gaudichaudi and A. lesueurii now forming their own species groups) and the A. inclinata-group (with A. gibbosa now forming its own group).
The geographic distribution of the species in the genus are summarized in the last three columns of the table below. The highest number of species occurs in the Pacific (17), followed by the Indian (16) and the Atlantic (12) Oceans. Ten species are cosmopolitan, recorded from all three major oceans, five (A. turriculata, A. frontieri, A. plana, A. echinogyra, and A.gibbosa) are Indo-Pacific, two (Atlanta inflata and A. californiensis) occur only in the Pacific, one (A. selvagensis) is Indo-Atlantic, and one (A. fragilis) has only been recorded from the Atlantic; no species are unique to the Indian Ocean. It should be noted that one species, A. meteori was previously regarded as Indo-Pacific, but was recorded from the northeastern Atlantic by de Vera, Seapy and Hernandez (2006) and must now be regarded as cosmopolitan.
The seven species groups, their contained species, the distinguishing features of each group and species, and each species' geographic distribution are presented in the table below. The species comprising each species group share the same radular type, usually the same opercular type, and, in many cases, the same eye type. Note that the Group Characteristics are not repeated under the Species Characteristics where they are shared by the members of that Species Group.
|Species Group||Group Characteristics||Species*||Species Characteristics||Maximal Shell Diameter (mm)||Number of Spire Whorls||Eye Type||Opercular Type||Radular Type||Atlantic Ocean ||Pacific Ocean ||Indian Ocean |
|A. brunnea- |
|Shell small; keel tall with rounded leading edge; spire tall conical or turreted, sculpted with complex ornamentation and with a prominent, mid-whorl spiral ridge||A. brunnea ||Spire tall conical and orange-red color; mantle light black||2.0||4||a||a ||I ||+||+||+|
|A. turriculata||Spire tall and turret shaped; spire light brown to red-brown||1.8||4-1/4||a||a ||I ||-||+||+|
|A. inflata- group||Shell inflated or flat; spire low conical with a large diameter (relative to adult shell size); surface of spire whorls smooth to sculptured with evenly-spaced spiral ridges||A. inflata||Shell inflated; spire low conical with weak to prominent low spiral ridges; spire sutures lack coloration; keel tall with truncate leading edge; keel base brown to yellow-brown||1.5||4-1/4 to 4-1/2||a||c ||I ||-||+||-|
|A. selvagensis||Shell inflated; spire low conical with sculpture ranging from none to well-developed and evenly-spaced low spiral ridges; spire sutures red-brown (magenta); keel base brown to yellow-brown ||2||3-1/2 to 3-3/4 ||a ||c ||I ||+||-||+|
|A. helicinoidea||Shell inflated, with body whorl broadly oval to rounded; keel of low to moderate height and rounded; spire with spiral ridges, moderately variable in expression; spire light purple or yellow to yellow-tan||2||4-1/2 to 4-3/4 ||c||c ||I ||+||+||+|
|A. californiensis||Shell flattened; keel of moderate height with truncate leading edge and a red- to orange-brown base; spire low conical to globular, and smooth; colorless to uniformly or mottled, light yellow, brown or violet||3.5||3-1/4||a||c ||I ||-||+||-|
|A. lesueurii- group||Shell spire very small; after larval metamorphosis, only a single and rapidly-expanding last whorl (teleoconch) is formed ||A. lesueurii||Shell entirely transparent; spire low and conical with prominent (deep) sutures; keel high, truncate||6||2-1/2||b||b ||I ||+||+||+|
|A. oligogyra||Shell faint pink to yellow; spire low and rounded with shallow sutures: keel of moderate height, rounded||3 ||2-1/2||a||b ||I ||+||+||+|
|A. peronii- group||Shell flat, of moderate to large size; radula type II, with bicuspid lateral teeth ||A. peronii||Shell clear, 