Description. — Shell fusiform, medium-sized to extremely large; outer lip usually medially convex, without adapical sinus; outer-lip edge usually with paired crenulations; inner lip adherent, abapically bearing two columellar folds and a more prominent fold at entrance of siphonal canal; adaxial margin of siphonal canal often erect; siphonal process parallel to axis of coiling.
Remarks. — The Fasciolariinae are morphologically similar to the fasciolariid subfamily Peristerniinae Tryon, 1880. Both groups are characterized by the presence of abapical columellar folds, an entrance fold to the siphonal canal situated immediately anterior to the columellar folds, and a (usually) crenulated, simple outer lip that is usually lirate on its inner (adaxial) side. These lirae are present in fully formed shells. However, mature individuals in Triplofusus Olsson & Harbison, 1953, are often smooth on the inner side of the outer lip, and all Africolaria lack such lirae. Internal lirae are created late in the shell depositional process, and a shell with an apparently complete lip (as evidenced by a relatively thick edge) may not yet have deposited its full complement of lirae. Nevertheless, the Fasciolariinae are relatively homogeneous in shell features. All Fasciolariinae have an adherent inner lip that merges imperceptibly into the shell exterior. The outer lip lacks an adapical sinus in all genera except some members of Australaria, a feature present in all Peristerniinae except some species of Hemipolygona Rovereto, 1899 (see Vermeij & Snyder, 2006). No fasciolariine has developed denticles on the inner side of the outer lip, features that are well-developed in several peristerniine genera including Peristernia Morch 1852, Turrilatirus Vermeij & Snyder, 2006, and Latirus Montfort, 1810, among others. The siphonal process of Fasciolariinae is always parallel to the axis of coiling, not deviated either dorsally or to the side as in some Peristerniinae. Although the Fasciolariinae and most Peristerniinae are characterized by the presence of abapical columellar folds, there are important differences in the magnitude and orientation of the folds. The folds in Fasciolariinae are elongate and very oblique and this character unites the species of the subfamily.
Besides the extremely large size of several fasciolariines, especially in Triplofusus, but also in Fasciolaria Lamarck, 1799, Pleuroploca P. Fischer, 1884 and the extinct new genus Pliculofusus (Terebraspira auctt, non Conrad, 1862), the Fasciolariinae have evolved three character states that are otherwise unknown in the Fasciolariidae. These are (1) an externally glazed shell (in the extinct genus Liochlamys Dall, 1889), indicating envelopment by the mantle or foot; (2) the extreme development of the entrance fold to the siphonal canal into a keel-like feature, as seen in the genera Australaria and Filifusus; and (3) the presence of distinct folds along the adaxial margin of the siphonal canal abapical to the entrance fold, as seen in adults of Pleuroploca, Pliculofusus and Terebraspira.
For genera that typically contain species with nodular axial ribs, our descriptions may only mention that condition. However, most species that typically have shells with nodular axial ribs also occur, not uncommonly, in anodose forms. Individuals or even local populations with anodose shells occur among species of Triplofusus, Pleuroploca, Filifusus, Granolaria, Aurantilaria, and Australaria, and several of these anodose forms have received separate names. Smooth forms of species with normally nodose shells may result from ecophenotypy (Aurantilaria aurantiaca), local geographic isolation (Filifusus filamentosus altimastus), regional variation (Pleuroploca trapezium audouini; P t. lischkeana) or for reasons not yet understood (Triplofusus giganteus reevei; Granolaria valenciennesii; Pleuroploca t. trapezium; Australaria australasia coronata; Lugubrilaria lugubris). And of course some genera have species with typically nodose shells and others with typically smooth (anodose) shells. If the type species has nodose shells, the other conditions may not be mentioned.
Taxonomically, most members of the Fasciolariinae have been assigned to two genera: Fasciolaria and Pleuroploca, though some American species have been placed in Triplofusus and the extinct Terebraspira and Liochlamys. These genera have not been critically compared or carefully defined, and in the case of Fasciolaria and Pleuroploca as conventionally used, they are heterogeneous, comprising several distinct clusters that we prefer to treat as separate gen¬era. We believe the proposal of formal generic names for these clusters will facilitate future molecular and phylogenetic studies of this surprisingly overlooked group of gastropods.

The Fasciolariinae are morphologically similar to the fasciolariid subfamily Peristerniinae Tryon, 1880. Both groups are characterized by the presence of abapical columellar folds, an entrance fold to the siphonal canal situated immediately anterior to the columellar folds, and a (usually) crenulated, simple outer lip that is usually lirate on its inner (adaxial) side. These lirae are present in fully formed shells. However, mature individuals in Triplofusus Olsson & Harbison, 1953, are often smooth on the inner side of the outer lip, and all Africolaria lack such lirae. Internal lirae are created late in the shell depositional process, and a shell with an apparently complete lip (as evidenced by a relatively thick edge) may not yet have deposited its full complement of lirae. Nevertheless, the Fasciolariinae are relatively homogeneous in shell features. All Fasciolariinae have an adherent inner lip that merges imperceptibly into the shell exterior. The outer lip lacks an adapical sinus in all genera except some members of Australaria, a feature present in all Peristerniinae except some species of Hemipolygona Rovereto, 1899 (see Vermeij & Snyder, 2006). No fasciolariine has developed denticles on the inner side of the outer lip, features that are well-developed in several peristerniine genera including Peristernia Morch 1852, Turrilatirus Vermeij & Snyder, 2006, and Latirus Montfort, 1810, among others. The siphonal process of Fasciolariinae is always parallel to the axis of coiling, not deviated either dorsally or to the side as in some Peristerniinae. Although the Fasciolariinae and most Peristerniinae are characterized by the presence of abapical columellar folds, there are important differences in the magnitude and orientation of the folds. The folds in Fasciolariinae are elongate and very oblique and this character unites the species of the subfamily.

Besides the extremely large size of several fasciolariines, especially in Triplofusus, but also in Fasciolaria Lamarck, 1799, Pleuroploca P. Fischer, 1884 and the extinct new genus Pliculofusus (Terebraspira auctt, non Conrad, 1862), the Fasci-olariinae have evolved three character states that are otherwise unknown in the Fasciolariidae. These are (1) an externally glazed shell (in the extinct genus Liochlamys Dall, 1889), indicating envelopment by the mantle or foot; (2) the extreme development of the entrance fold to the siphonal canal into a keel-like feature, as seen in the genera Australaria and Filifusus; and (3) the presence of distinct folds along the adaxial margin of the siphonal canal abapical to the entrance fold, as seen in adults of Pleuroploca, Pliculofusus and Terebraspira.