[Gastropoda • 2019] Landouria strobiloides • First Verified Record of the Genus Landouria Godwin-Austen, 1918 (Stylommatophora: Camaenidae) from Thailand with Description of A New Species

Landouria strobiloides

C. Tumpeesuwan & S. Tumpeesuwan, 2019

RAFFLES BULLETIN OF ZOOLOGY. 67.

Abstract

A new species of land snail is described from the Suan Hin Pha Ngam Limestone Area in Loei Province, northeastern Thailand. This species is placed in the genus Landouria Godwin-Austen, 1918 based on the presence of a slightly long club-shaped flagellum with variably sized tubercles, a gametolytic sac with swollen basal part, and absence of dart sacs and mucous glands. This is the first verified record of the genus Landouria in Thailand. 

Key words. new species, Landouria, Aegista, Thaitropis, reproductive anatomy, Loei Province, Thailand 

Fig. 2. Living specimen of Landouria strobiloides, new species. Photograph by: Benchawan Nahok.

Fig. 3. Empty shell of Landouria strobiloides, new species, holotype (NHMSU-00017). Photograph by: Benchawan Nahok.

Superfamily Helicoidea Rafinesque, 1815 

Family Camaenidae Pilsbry, 1895 

Genus Landouria Godwin-Austen, 1918

Landouria strobiloides, new species

Diagnosis. Body whorl of shell with very sharp keeled, aperture slightly thickened and with a reflexed rim. Flagellum slightly long, club-shaped, with variably-sized tubercles. Base of gametolytic sac enlarged and swollen.

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Etymology. The specific epithet strobiloides derived from the strobilus, referring to the flagellum of the new species, which looks similar to the strobilus of non-flowering plants because it possesses many tubercles on its surface. 

Remarks. The genitalia of the new species agree in general detail with the genital anatomy of congeneric species, but it has the longest tubercles on the flagellum within the genus. The anatomy of Landouria differs from Aegista by the absence of a well-developed dart sac, lateral accessory sacs, and mucous glands (Schileyko, 2004). In Thailand, the snails that have the last whorl slightly descending in front and large umbilicus were assigned to Aegista, but this needs to be confirmed by a study of their anatomical characters.

Chanidaporn Tumpeesuwan and Sakboworn Tumpeesuwan. 2019. First Verified Record of the Genus Landouria Godwin-Austen, 1918 from Thailand (Gastropoda: Stylommatophora: Camaenidae) with Description of A New Species. RAFFLES BULLETIN OF ZOOLOGY. 67; 298–305. lkcnhm.nus.edu.sg/app/uploads/2018/11/RBZ-2019-0021.pdf

 Takahiro Hirano, Yuichi Kameda, Kazuki Kimura and Satoshi Chiba. 2014. Substantial Incongruence Among the Morphology, Taxonomy, and Molecular Phylogeny of the Land Snails Aegista, Landouria, Trishoplita, and Pseudobuliminus (Pulmonata: Bradybaenidae) occurring in East Asia. Molecular Phylogenetics and Evolution. 70; 171-181. DOI:  10.1016/j.ympev.2013.09.020

[Gastropoda • 2018] Aenigmatoconcha sumonthai • A New Helicarionid Land Snail (Helicarionidae: Durgellinae) from Chumphon Province, Southern Thailand

 Aenigmatoconcha sumonthai

C. Tumpeesuwan & S. Tumpeesuwan, 2018

 RAFFLES BULLETIN OF ZOOLOGY. 66 

 Abstract

 Aenigmatoconcha sumonthai, new species, is described from Tham Chang Phueak, a limestone range in Chumphon province, southern Thailand. The external morphology of the shell and soft parts, the genital system, and radula morphology were examined and compared with the type species of the genus, A. clivicola C. Tumpeesuwan & S. Tumpeesuwan, 2017 from northeastern Thailand. Externally the new species differs from A. clivicola in having a smaller shell, presence of black bands from the base of the long tentacles to the mantle edge, and both mantle shell lobes have numerous tiny white spots and irregular black marbling. The radula comprises approximately 22–35 transverse v-shaped rows of teeth, with each row having 11–150 unicuspid spatulated teeth. In the genital system, the penis is longer than the epiphallus and the base of the gametolytic sac is longer than the middle part. 

Key words. Aenigmatoconcha, mantle shell lobes, radula, karst, endemic taxa, disjunct distribution 

Fig. 2. Aenigmatoconcha sumonthai, new species, in natural habitat at the type locality; photographs taken on June 2017. A, two snails with the dorsal shell surface complately covered by the mantle shell lobes; B, two snails with mantle shell lobes retracted. (Photograph courtesy of Mr. Montri Sumontha).

Superfamily Helicarionoidea Bourguignat, 1877

Family Helicarionidae Bourguignat, 1877

Subfamily Durgellinae Godwin-Austen, 1888

Tribe Durgellini Godwin-Austen, 1888

Genus Aenigmatoconcha C. Tumpeesuwan & S. Tumpeesuwan, 2017

Type species. Aenigmatoconcha clivicola C. Tumpeesuwan & S. Tumpeesuwan, 2017

Aenigmatoconcha sumonthai, new species

Etymology. The species is named after the collector Montri Sumontha; the specific epithet “sumonthai” is from the family name “Sumontha”.

Diagnosis. The characters distinguishing Aenigmatoconcha sumonthai, new species, from A. clivicola are the colour patterns on mantle shell lobes and body, as well as morphology of radula and genital organs. Mantle shell lobes bear irregular black marbling pattern and numerous tiny white spots (Fig. 2A). Two black bands, each running from the base of a long tentacle (eyestalk) to mantle edge, are present (Fig. 2A). Central teeth of radula have a globose unicuspid cusp, with their size smaller than the 1st lateral teeth and only the distal halves of the globose cusps emerge from the 1st lateral teeth (Fig. 4C). The epiphallus is shorter than penis, and the middle part of the gametolytic sac in the new species is shorter than in A. clivicola (Fig. 5).

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Chanidaporn Tumpeesuwan and Sakboworn Tumpeesuwan. 2018. Aenigmatoconcha sumonthai, A New Helicarionid Land Snail from Chumphon Province, Southern Thailand (Helicarionidae: Durgellinae). RAFFLES BULLETIN OF ZOOLOGY. 66; 170–176. 

 lkcnhm.nus.edu.sg/app/uploads/2018/01/66rbz170-176.pdf

[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 

 lkcnhm.nus.edu.sg/nus/index.php/65

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: Sophina, Chalepotaxis, Aenigmatoconcha, 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 clivicola, new 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. 

http://lkcnhm.nus.edu.sg/nus/images/data/raffles_bulletin_of_zoology/vol65/65rbz181-188.pdf

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