Austrolittorina Rosewater, 1970

Reid, DG & Williams, ST, 2004, The Subfamily Littorininae (Gastropoda: Littorinidae) in the Temperate Southern Hemisphere: The Genera Nodilittorina, Austrolittorina and Afrolittorina, Records of the Australian Museum 56, pp. 75-122 : 86

Austrolittorina Rosewater, 1970

Littorina (Austrolittorina) Rosewater, 1970: 467 (type Littorina unifasciata Gray, 1826 , by original designation).

Taxonomic history. This generic name was introduced as a subgenus of Littorina (implicitly by reason of the smooth, spirally striate shell of its members, see Taxonomic History of Nodilittorina , above). In the original diagnosis, Rosewater (1970) mentioned a “predominantly southern ocean and tropical distribution”, “flattened columella and crescentshaped area on the adjacent part of the shell” (i.e. the eroded parietal area), and a penis with single penial gland and penial glandular disc (in terminology of Reid, 1989; i.e. penis of the type characteristic of Nodilittorina s.l.). No unique features were identified by which to define the group and, in addition to the species here included, at least nine others (belonging to Echinolittorina , Afrolittorina and Littoraria in current classification) were listed. Three further species were added subsequently (Ponder & Rosewater, 1979). As discussed above, with new insights into the anatomy of littorinids the definition of Nodilittorina was broadened and Austrolittorina placed in its synonymy (Bandel & Kadolsky, 1982; Reid, 1989). The name was not used again until Reid (2002 a) provisionally employed it as a subgenus of Nodilittorina , to denote eight or nine Southern Ocean species united by a loop of the egg groove within the capsule gland of the pallial oviduct ( N. araucana was not then recognized as belonging to this group). Formal phylogenetic analysis of the morphological characters of Nodilittorina s.l. failed to confirm these ten southern species as a clade, and as a result no taxonomic decisions were made ( Reid, 2002 b).

In a recent molecular study, all ten of these southern littorinines were included and the five species here included in Austrolittorina appeared as a strongly supported clade; the name was therefore used at the rank of genus for the first time, and a formal diagnosis given ( Williams et al., 2003). Of the morphological characters listed in the following diagnosis, none is unique. One that is, however, distinctive is the absence of axial colour markings (i.e. axial lines, or axially aligned series of spots or dashes) that characterize the majority of littorinine species. Shells are not always of the bluish-white appearance of the type species, A. unifasciata ; A. araucana may be brown or whitish and A. cincta typically has spiral brown lines.

Diagnosis. Shell not nodulose; spiral striae or smooth; eroded parietal area; no pseudoumbilicus; white with peripheral blue-grey band, brown, or with spiral brown lines; no axial colour pattern. Cephalic tentacles black. Penis with swollen filament; base bifurcate; single mamilliform gland adjacent to glandular disc of subepithelial glandular tissue; penial vas deferens an open groove. Paraspermatozoa with short, curved or coiled rod bodies, or rod bodies absent. In pallial oviduct egg groove makes a simple loop through albumen gland, circular loop (or only slight flexure) through capsule gland, no loop in jelly gland; copulatory bursa opens in anterior or posterior position. (After Williams et al., 2003.)