Echinolittorina

Reid, David G., 2009, The genus Echinolittorina Habe, 1956 (Gastropoda: Littorinidae) in the western Atlantic Ocean 2184, Zootaxa 2184 (1), pp. 1-103 : 27-28

Subgenus Lineolittorina new subgenus

Type species: Littorina lineolata d’Orbigny, 1840 .

Etymology: Contraction of lineolata and Littorina , in reference to the type species.

Diagnosis: As for the only known species, E. lineolata (below).

Remarks: Morphologically, E. lineolata resembles members of the following subgenus, Amerolittorina , in characters of both shell and anatomy. There are two unusual features. First, the penial filament is swollen with subepithelial glands, whereas in all other Echinolittorina species the glandular material in the filament is much less extensive, and the filament is more narrowly pointed or tapering. Second, the major rod-piece in each of the paraspermatozoa is straight, but there is usually also a coiled inclusion. Among other Echinolittorina species similar curved rod-pieces have been described only in the E. leucosticta and E. millegrana groups of the subgenus Granulilittorina ( Reid 2007) and elsewhere in the Littorininae only in the genus Austrolittorina ( Reid 2002a; Reid & Williams 2004). These groups do not show any close phylogenetic relationship ( Williams et al. 2003; Williams & Reid 2004) and therefore the feature must have been independently derived.

These morphological characters are insufficient to conclude anything about the phylogenetic affinities of E. lineolata ( Reid 2002a) . Molecular analyses fail to group it with any other Echinolittorina with significant support. It was first weakly linked with E. peruviana ( Lamarck, 1822) near the base of the Echinolittorina phylogeny ( Williams & Reid 2004) and then placed on its own as a basal lineage in a subsequent analysis ( Williams & Duda 2008). The new subgenus is created to reflect the phylogenetic isolation of E. lineolata .