Thursday, 6 September 2007

Thursday gastropod: Thersites Pfeiffer 1855

[Thersites] was the ugliest man of all those that came before Troy — bandy-legged, lame of one foot, with his two shoulders rounded and hunched over his chest. His head ran up to a point, but there was little hair on the top of it.

Pfeiffer should have been red-carded when he used the name of this loathsome character from the Iliad for a genus of three rather fetching camaenid snails from mid-eastern Australia.

Not that Thersites has been without its critics. Iredale (1933) proposed that it be ditched as a generic name and replaced with Annakelea. He didn't suggest this because it was an unfair reflection on the handsomeness of the shells. He argued it on a dodgy taxonomic point.

(Anyone not mesmerised by the minutiae of taxonomy might want to skip down to the pictures. Still reading? Don't say I didn't warn you.)

Pfeiffer (1855) introduced Thersites without nominating a type species. (A type species provides an objective standard of reference for the genus.) Martens (1860) subsequently designated Reeve’s Helix richmondiana as the type. But Iredale (1933: 42), stretching the rules of nomenclature to snapping point, argued that the “tautonymic type of Thersites must be H. thersites Broderip” and, as this was not an Australian species (it was described from Mindoro in the Philippines), deemed the generic name inappropriate. “So Thersites must be dismissed from Australian malacological study,’ Iredale wrote, possibly with an unseemly flourish.

He provided an alternative genus name — Annakelea — retaining H. richmondiana as type species and adding H. novaehollandiae Gray and H. mitchellae Cox.

However, Thersites was perfectly acceptable under the rules of nomenclature. Iredale's argument didn't hold water, so Annakelea bit the dust and entered into synonymy.

Thersites richmondiana (Reeve 1852) is a large species (max. width about 50 mm) from rainforests and wet sclerophyll from southern Queensland to northern New South Wales.

Richmond River, NSW

With a maximum width of 40 mm, T. novaehollandiae (Gray 1834) is the smallest of the three Thersites. It occurs in northern New South Wales from Glen Innes south to Port Stephens.

Dorrigo, NSW

Once common in suitable habitat in northern New South Wales, extensive clearing has restricted T. mitchellae (Cox 1864) to a few locations. The most important of these is Stotts Island in the Tweed River near Murwillumbah.

Byron Bay, NSW


Bishop, MJ. (1978) A revision of the genus Thersites Pfeiffer (Pulmonata: Camaenidae). Journal of the Malacological Society of Australia 4(1–2): 9–21.

Iredale, T. (1933) Systematic notes on Australian land shells. Records of the Australian Museum 19: 37–59.

Von Martens, EC. (1860). Nachträge in Albers, JC. Die Heliceen, nach natürlicher Verwandtschaft systematisch geordnet. 2. Leipzig: Wilhelm Engelman.

New South Wales National Parks and Wildlife Service. (2001). Mitchell's rainforest snail Thersites mitchellae (Cox, 1864) recovery plan. NPWS, Hurstville, NSW.

Pfeiffer, L. (1855). Versuch einer Anordnung der Heliceen nach natürlichen Gruppen. Malakozoologische Blätter 2: 112–144.

1 comment:


Too bad back in Pfeiffer's time taxonomists rarely explained the reasoning behind the new names they were creating.