Wednesday, June 7, 2017

[Gastropoda • 2017] Aenigmatoconcha clivicola • Discovery of An Overlooked Helicarionid Land Snail (Helicarionidae: Durgellinae) from northeastern Thailand, with Description of A New Genus and New Species, and Note on Radula Morphology and Genital System


หอยพิศวงเขาหินปูน  |  Aenigmatoconcha clivicola
  Tumpeesuwan & Tumpeesuwan, 2017 


Abstract
 Aenigmatoconcha clivicola, new genus and new species, was described from a limestone hill in Loei Province, northeastern Thailand. Morphological features of the shell, genital system, and radula were examined and compared with Sophina calias and S. schistostellis from Southeastern Myanmar, and Chalepotaxis infantilis from Southern China. It differs from all previously described Sophina species due to its more flattened and depressed, thin glossy shell, and its soft parts possessing broad right and left mantle shell lobes. The radula comprises approximately 20–25 transverse V-shaped rows of teeth; each row having 17–137 unicuspid spatulate teeth. The genital system lacks an amatorial organ and has a very large cylindrical penis without a penial sheath. 

Key words: SophinaChalepotaxisAenigmatoconcha, V-shaped rows of teeth, amatorial organ, limestone dweller

Living Aenigmatoconcha clivicola, new species, in natural habitat.  

Superfamily Helicarionoidea Bourguignat, 1877 
Family Helicarionidae Bourguignat, 1877 
Subfamily Durgellinae Godwin-Austen, 1888

Tribe Durgellini Godwin-Austen, 1888 

Aenigmatoconcha, new genus 
Type species. Aenigmatoconcha clivicolanew species. 

Diagnosis. The radula possesses similar unicuspid spatulate teeth arranged in V-shaped rows. The genitalia lack an amatorial organ and possess a large, stout penis and slender elongate epiphallus. 

Etymology. “Aenigma” from the Latin word meaning something obscure, a riddle or mystery, and “concha” from the Latin word meaning snail or shell. 

Remarks. The radula and genital organs form the unique characters distinguishing Aenigmatoconcha, new genus, from other morphologically close helicarionid genera. 

Aenigmatoconcha clivicola, new species, in natural habitat. A, living snail; B, foraging behavior.
 Photographs: Kitti Tanmuangpak. 

Aenigmatoconcha clivicola, new species
Helicarionidae gen. indet.: Tanmuangpak et al., 2012: 18–24.
 Sophina sp.: Tanmuangpak. 2016: 93–94.

Etymology. The specific epithet “clivicola” comes from two Latin words: “clivus”, meaning sloping side of hill, and “-cola”, meaning dweller.


Chanidaporn Tumpeesuwan and Sakboworn Tumpeesuwan. 2017. Discovery of An Overlooked Helicarionid Land Snail (Helicarionidae: Durgellinae) from northeastern Thailand, with Description of A New Genus and New Species, and Note on Radula Morphology and Genital System. RAFFLES BULLETIN OF ZOOLOGY. 65; 181–188. 


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