Margarya melanioides

Margarya melanioides
Apertural view of a shell of Margarya melanioides.
Conservation status
Endangered  (IUCN 3.1) [1]
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Mollusca
Class:	Gastropoda
Subclass:	Caenogastropoda
Order:	Architaenioglossa
Family:	Viviparidae
Genus:	Margarya
Species:	M. melanioides
Binomial name
Margarya melanioides Nevill, 1877 [2]
Synonyms [1] [3] [4]
Margarya melanoides (spelling error) [1] Margarya melanioides carinata Neumayr Margarya melanoides delavayi Mabille Vivipara delavayi Mabille, 1886 [5] Paludina margeriana Anderson, 1878 Vivipara (Tulotoma) margeriana Neumayr,1883 Vivipara (Tulotoma) margeriana var. tuberculata Neumayr,1883

Margarya melanioides is a species of large operculate freshwater snail, an aquatic gastropod mollusc in the family Viviparidae, the river snails.

Margarya melanioides is the type species of the genus Margarya. ^{[2] [6]}

Distribution

The distribution of Margarya melanioides includes Dian Lake, Erhai Lake, Jianhu Lake, Xihu Lake, and Cibi Lake in Yunnan Province, China. ^{[1] [4]} Former records in Daduitai Lake and Xingyun Lake are considered as a result of the mix-up of species name. ^[4]

An average population density was 36 individuals per square meter in Dianchi Lake in 1940s, ^[7] 0.7 individuals per square meter in 1990s ^[7] and 0.068 individuals per square meter in Dianchi Lake in 2012. ^[7]

According to the population ecology research by Song et al. (2013), ^[7] the population of will collapse in the Dian Lake in 2015. ^[7]

Description

The width of the shell is up to 64.3 mm. The height of the shell is up to 94.7 mm. ^[4]

Shu et al. (2010) provided details about the shell and about the radula. ^[3]

The diploid chromosome number of Margarya melanioides is 2n=18. ^{[3] [8]}

Ecology

Margarya melanioides is a dioecious species. ^[7] Females are ovoviviparous and one female lay 5-6 eggs per year. ^[7] The newborn shell is about 8 mm in height. ^[7] The snail will reach maturity in one year in a shell height about 30 mm. ^[7]

The lifespan is 3–4 years. ^[7]

Human use

This species is extensively harvested as a human food source, but harvesting is one of its threats. ^[7]

References

1. Aldridge D., Di L., Jiang Y. & McIvor A. (2009). "Margarya melanoides" (sic!). In: IUCN 2013. IUCN Red List of Threatened Species. Version 2013.2. <www.iucnredlist.org>. Downloaded on 22 February 2014.
2. Nevill G. (1877). "List of the Mollusca brought back by Dr. Anderson from Yunnan and Upper Burma, with descriptions of new species". Journal of the Asiatic Society of Bengal 46(2): 14-41. page 30.
3. Shu, F.; Köhler, F.; Wang, H. (2010). "On the shell and radular morphology of two endangered species of the genus Margarya Nevill, 1877 (Gastropoda: Viviparidae) from lakes of the Yunnan Plateau, Southwest China". Molluscan Research. 30 (1): 17–24.
4. Zhang, L. J.; Chen, S. C.; Yang, L. T.; Jin, L.; Köhler, F. (2015). "Systematic revision of the freshwater snail Margarya Nevill, 1877 (Mollusca: Viviparidae) endemic to the ancient lakes of Yunnan, China, with description of new taxa". Zoological Journal of the Linnean Society . 174 (4): 760–800. doi: 10.1111/zoj.12260 .
5. Mabille J. (1886). "Déscription de vivipares nouvelles du Lac Ta-Ti". Bulletins de la Société malacologique de France 3: 65–76. page 66, plate II, figs 1a, 1b.
6. Du, L.; Yang, J.; von Rintelen, T.; Chen, X.; Aldridge, D. (2013). "Molecular phylogenetic evidence that the Chinese viviparid genus Margarya (Gastropoda: Viviparidae) is polyphyletic". Chinese Science Bulletin . 58 (18): 2154–2162. doi: 10.1007/s11434-012-5632-y .
7. Song, Zhuoyan; Zhang, Junqian; Jiang, Xiaoming; Wang, Chouming; Xie, Zhicai (2013). "Population structure of an endemic gastropod in Chinese plateau lakes: evidence for population decline" . Freshwater Science . 32 (2): 450–461. doi:10.1899/12-099.1.
8. Chen Y. X., Zhang N. G., Zhang W. & Li J. K. (1996). "The karyotype study of Margarya yaungtsunghaiensis and M. melanioides (Viviparidae)". Zoological Research17: 94-96. (In Chinese with English abstract)

External links

• (in Chinese) Zhang L. (1986). "Study on the morphological variation of Margarya melanioides and M. monodi from Dian-Chi, Yunnan." Transactions of the Chinese Society of Malacology2: 65–71. (In Chinese with English abstract)