Drymaeus expansus
| Drymaeus expansus | |
|---|---|
| Different views of a syntype specimen of D. iodostomus, a junior synonym of D. expansus, held at the MNHN, Paris | |
| Scientific classification | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Mollusca |
| Class: | Gastropoda |
| Order: | Stylommatophora |
| Family: | Bulimulidae |
| Genus: | Drymaeus |
| Species: | D. expansus
|
| Binomial name | |
| Drymaeus expansus (L. Pfeiffer, 1848)
| |
| Synonyms[2][3] | |
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List
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Drymaeus expansus is a species of tropical air-breathing land snail, a pulmonate gastropod mollusc in the family Bulimulidae that is native to parts of South America. It was described in 1848, with Huallaga, in Peru, as the type locality. The animal has a streaked shell, white to brownish in color, measuring 40 mm in length and 22 mm in width with 7 whorls. It has an open umbilicus and is densely striated longitudinally, also featuring a markedly expanded peristome in all directions.
Phylogenetic analyses based on genetic markers place Drymaeus expansus in a clade that also includes the species D. branneri and D. pamplonensis. However, given the great diversity of the genus Drymaeus and the small number of species analyzed, these data are still considered preliminary.
Taxonomy and nomenclature
The species was first described in 1848 by German conchologist Ludwig Karl Georg Pfeiffer as Bulimus expansus. Pfeiffer mentioned the Amazonian region of Huallaga, in Peru, as the type locality.[1] The specific epithet expansus originates from Latin, meaning "stretched" or "extended".[4]
According to MolluscaBase, the mollusk-oriented branch of WoRMS,[5] Drymaeus expansus includes two subspecies: Drymaeus expansus expansus, the nominate subspecies, and Drymaeus expansus scitus (H. Adams, 1867).[2]
Description
The shell of Drymaeus expansus has an ovate-pyramidal shape with brownish-white base color ornamented by fulminate (lightning-like) brownish streaks. It attains a length of 40 mm and diameter of 22 mm at around 7 whorls.[1] The body whorl is nearly equivalent to the spire in length. The shell is densely striated longitudinally and also perforated, meaning it has an opened umbilicus. The aperture is colored violet internally, the columella presents an internal fold, and the peristome is distinctly slanted, extending outwards in all directions.[1]
Phylogeny
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| Molecular phylogeny of Drymaeus and related genera after Rosa et al., 2025[6] |
Genetic studies using both mitochondrial and nuclear markers, specifically COI, H3, and ITS2/28S, have placed Drymaeus expansus within a clade that also includes Drymaeus pamplonensis and Drymaeus branneri. This group appears to be closely related to species from the genera Mesembrinus and Antidrymaeus.[6] The genus Drymaeus, however, is highly diverse, with an estimated 300 species, and more comprehensive samplings in future analyses may lead to different phylogenetic tree structures.[6] As it stands, the connections between D. expansus and related species remain tentative, and current findings are considered preliminary.[6]
References
- ^ a b c d Pfeiffer, Ludwig K.G. (1848). Monographia heliceorum viventium : sistens descriptiones systematicas et criticas omnium huius familiae generum et specierum hodie cognitarum. Leipzig: Brockhaus. p. 60.
- ^ a b "MolluscaBase - Drymaeus expansus (L. Pfeiffer, 1848)". www.molluscabase.org. Retrieved 9 June 2025.
- ^ Salvador, Rodrigo B.; Miranda, Marcel S.; Silva, Fernanda S.; Oliveira, Cléo D. C.; Arruda, Janine O.; Cavallari, Daniel C.; Gomes, Suzete R.; La Pasta, Ariel; Pena, Meire S.; Ovando, Ximena M. C.; Rosa, Rafael M.; Salles, Anna C. A.; Santos, Sonia B.; Simone, Luiz R. L.; Machado, Fabrizio M. (2024). "Checklist of the terrestrial gastropods of Brazil". Journal of Conchology. 45 (2): 157–158. doi:10.61733/jconch/4516.
- ^ Brown, R. W. (1954). Composition of Scientific Words (PDF). Baltimore, Maryland, USA: Published by the author. p. 744.
- ^ "MolluscaBase". www.molluscabase.org. Flanders Marine Institute. Retrieved 22 April 2025.
- ^ a b c d Rosa, Rafael M.; Salvador, Rodrigo B.; Cavallari, Daniel C. (2025). "The disappearing act of the magician tree snail: anatomy, distribution, and phylogenetic relationships of Drymaeus magus (Gastropoda: Bulimulidae), a long-lost species hidden in plain sight". Zoological Journal of the Linnean Society. 203 (3): zlaf017. doi:10.1093/zoolinnean/zlaf017.