Evolution & Systematics

There are 107 living species and subspecies, across 5 genera and 18 subgenera, within the caenogastropod family Strombidae (figure 1). The family, along with the families Struthiolariidae and Aporrhaidae, belongs to the superfamily Stromboidea (Kreipl & Poppe 1999). Comparisons between the families Strombidae, Aporrhaidae, Xenophoridae and Struthiolariidae suggest that these families likely evolved from a common aporrhaid-like ancestor. Aporrhaids are likely the most primitive members of the Strombacea but share typical characteristics such as juveniles lacking the expanded lips of the mature adult (Perron 1978).

The fossil record of the Strombidae is good, and many aspects of the life of recent strombids are well documented (Savazzi 1991). The first forms of the genera Prestombus (Douville, 1929) and Pugnellus (Conrad, 1860) appeared in the Upper Cretaceous period 95-65 million years ago; these can be considered as the origin of Strombus (Kreipl & Poppe 1999). Phylogenetic relationships remain unclear but are generally accepted. Strombidae were essentially represented by a group resembling Tibia during the Cenozoic (60 million years ago) with the true Strombus starting to appear during the Eocene (48 million years ago) (Kreipl & Poppe 1999). In fossil Strombacea, the question arises whether their broad wings are primarily “snowshoes”, or stabilizers during locomotion. In a few Cretaceous Aporrhaidae, the combination of broad wings or extremely elongated spines, very light shells and occurrence in chalk or ooze (often together with other organisms possessing snowshoe adaptations) suggest a snowshoe function. However, in Tertiary Strombidae, the heavier shells, stronger and less projecting spines and preference for medium- and coarse-grained sediments point to a stabilizing function during locomotion (Savazzi 1991).

The phylogenetic positioning of Lentigo lentiginosus remains a little unclear. Currently its position within the subgenus Lentigo is accepted on morphological grounds, however genetic analysis suggests it may not sit within the same clade as other Lentigo species L. latus and L. granulates (Latiolais et al. 2006).