Rhagada Albers, 1860

Köhler, Frank, 2014, On the land snail Rhagada Albers, 1860 (Gastropoda: Camaenidae) from across the Lesser Sunda Islands, Raffles Bulletin of Zoology 62, pp. 115-123 : 116-118

Rhagada Albers, 1860

Rhagada Albers, 1860 [in Martens & Albers]: 108–109 (type species Helix reinga Pfeiffer, 1846 by original designation); Pilsbry, 1890: 185–191, 1894: 135–136; Martens, 1891: 235–236; Preston, 1908: 120, 1914: 13; Hedley, 1916: 69–70; Rensch, 1931: 94–95, Iredale, 1938: 112–113, 1939: 58–63; Solem, 1985a: 875–919, 1985b: 143–136, 1991: 217–218, 1997: 1663–1789; Solem & McKenzie, 1991: 247–263; Johnson & Black, 1991: 367–374; Withers et al., 1997: 599–611; Falconieri, 1995: 81–84; Vermeulen & Whitten, 1998: 127–128; Johnson et al., 2004: 341–355; 2006: 45–50; Maassen, 2009: 65–69; Köhler, 2011: 270–287; Stankowski, 2011: 756–769, 2013: 2726–2741; Johnson et al., 2012: 316–327; Köhler & Criscione, 2013: 1971–1982.

Bellrhagada Iredale, 1938: 114, 1939: 71–72 (type species Rhagada plicata Preston, 1914 , by original designation).

Tumegada Iredale, 1939: 62 (type species Helix convicta Cox, 1876 , by original designation).

Taxonomic history. Solem (1985a) synonymised Bellrhagada and Tumegada . There are about 35 species in Western Australia, which are comparatively well-known. Six nominal species have so far been described from the Lesser Sunda Islands. Rensch (1931) grouped the species known at the time into two polytypic species (so-called “Rassenkreise”) based on shell features. He considered R. colona (Martens, 1877) and R. supracostulata ( Schepman, 1892) as subspecies of the Australian “ R. plectilis (Benson, 1853) ” (= Plectorhagada plectilis ) for having a small shell with strong axial ribs. However, P. plectilis has since been shown to be part of a different genus ( Solem, 1997). Rensch (1931) also recognised a second polytypic species, R. solorensis (Martens, 1863) with its subspecies R. solorensis floresiana ( Martens, 1891) , as a distinct species for its larger shell and faint axial ribs. Subsequently, Maassen (2009) reinstated R. colona and R. supracostulata as full species but maintained the subspecies arrangement for R. solorensis and R. s. floresiana without explanation. In addition, he described a new species from Alor island, R. setzeri Maassen, 2009 . Earlier, Falconieri (1995) also described a new species from Nusa Penida, R. marghitae . However, this description was apparently overlooked subsequently. Except for the description of R. setzeri , all taxonomic decisions were based on shell features only. Characters considered particularly relevant for the taxonomy of Rhagada species were shell size, development of axial ribs, and closure of umbilicus.

Diagnosis. Shell small to medium-sized (D = 9–25 mm), subglobose with moderately to strongly elevated, exceptionally also low spire; umbilicus frequently concealed by greatly expanded callus, occasionally forming a chink or narrowly open; protoconch smooth to weakly sculptured by radial ridgelets or ribs; teleoconch with faint to well-developed sculpture of axial ridgelets or ribs, mostly on upper sector of whorls; whorls separated by shallow suture; periphery wellrounded to weakly angulated. Shell colour generally variable, background whitish or brownish horn, with well-developed, red subsutural, peripheral and frequently additional, thinner spiral bands. Eversible head wart between ommatophores. Penis without penial sheath, with well-developed, long and coiled epiphallus with flagellum of variable length; penial retractor muscle attached at epiphallus; epiphallus opens to lumen of penial chamber through large, cone-shaped verge with characteristic sperm groove. Bursa copulatrix short to long, simple to kinked (based on Köhler, 2011).