Corona Albers, 1850

Breure, Abraham S. H. & Avila, Valentin Mogollon, 2016, Synopsis of Central Andean Orthalicoid land snails (Gastropoda, Stylommatophora), excluding Bulimulidae, ZooKeys 588, pp. 1-199 : 42

Taxon classification Animalia Stylommatophora Orthalicidae

Genus Corona Albers, 1850

Achatina (Corona) Albers 1850: 193.

Type species.

Helix (Cochlitoma) regina Férussac, 1821, by subsequent designation (Martens in Albers, 1860).

Diagnosis.

Shell dextral or sinistral (eniantomorphy), elongate-ovate, solid, shining, height up to ca. 80 mm (study area), corneous or pinkish ground colour, uniformly or (usually) with a dark or light peripheral band (mostly with arrow shaped markings) and axial streaks of reddish-brown, sculptured with growth striae, aperture (narrowly) subovate, peristome simple, parietal and columellar walls dark-brown to blackish.

Distribution.

Colombia, Ecuador, Peru, Bolivia, Brazil, French Guiana, Suriname, Guyana,?Venezuela.

Habitat.

Species of this genus live supposedly most of the time at canopy level in lowland tropical rainforest (W.J.M. Maassen, unpublished data); at occasions they descent downwards and may be found on tree stems or near the ground.

Anatomy.

Schileyko 1999: Corona perversa (Swainson, 1821) [g, m, as Laeiorthalicus reginaeformis (Strebel, 1909)]; Breure and Mogollón 2010: Corona pfeifferi (Hidalgo, 1869) [g].

Phylogenetic data.

Breure et al. 2010: Corona pfeifferi (Hidalgo, 1869).

Remarks.

Species of this genus show quite some variation and their distinction is, with some exceptions, difficult as they are often found in low numbers (one or a few shells at most) at a specific locality. Moreover, several species show enantiomorphy, which may add to taxonomic confusion. Distributional records for species in this group thus need to be viewed in this context. Due to their hidden habitat at the canopy level their distribution records probably do not reflect their true occurrence.

The taxonomy of this group is hampered by the fact that a) most species described are morphologically very similar; b) the type material of some species has either not been located or is worn, thus making comparative research difficult; c) intraspecific variation is insufficiently known, and anatomical and molecular data is rare; and d) many records in museum collections often have imprecise localities. Moreover, the distribution of these species over the larger part of the vast continent of South America, with the same species in unverified museum collections reportedly occurring at locations ca. 2500 km apart (e.g., central Bolivia and French Guiana), is puzzling. We regard it as suspicious for two species to occur sympatrically at such distances without distinct differences. For the time being, as many lots in museum collections may have been misidentified, it is here suggested that 1) Corona incisa ( Hupé, 1857) is used for occurrences in the southern distribution range (Bolivia, adjacent areas of Peru and Brazil), 2) Corona regalis ( Hupé, 1857) for specimens from western Brazil, central and northern Peru, Ecuador and southeastern Colombia, and 3) Corona regina ( Férussac, 1823) for records from the northwestern distribution range (Brazil, French Guiana, Suriname). Unverified records from these areas have been plotted as Corona sp. in the distribution maps. Corona pfeifferi (Hidalgo, 1869) is a species that, within the study area, may be unambiguously recognized. The taxonomy of this group thus urgently needs further revision, preferably with molecular research from samples throughout the distribution range.