Anatomy and histology of a new species of Enotepteron (Cephalaspidea: Gastropteridae) from tropical northeastern Australia

Abstract

The anatomy and histology of a new species of gastropterid cephalaspidean, Enotepteron heikeae, sp. nov., from tropical Australia is described. Enotepteron is the least documented of the gastropterid genera with only two previously recorded species, from Yellow Sea (North Pacific) and the Seychelles (Indian Ocean). The unique features of E. heikeae, within the genus, are the long thin tail (posterior end of the foot), cuticular penial armature, and a bilobed prostate. The investigation also reveals the presence of a very large anal gland. This gland maybe a useful taxonomic region, and its discovery considerably broadens the previously known geographical occurrence of the genus. Documentation and investigation of this species improves our knowledge of the morphological variation across the genus, and allows reassessment of the generic features to show that the presence of spheres to the posterior edge of the parapodia may be the only unifying character.