開放新擬釘螺

開放新擬釘螺（學名：Neotricula aperta）是新擬釘螺屬的其中一個淡水螺物種，屬於蓋螺科的淡水生腹足綱軟體動物。

過往這個物種是本屬唯一的一個物種；但現時此屬已有至少兩個已描述的物種。

開放新擬釘螺已知是湄公血吸蟲（Schistosoma mekongi）的唯一中間宿主，可引致湄公血吸蟲病。

## 分佈

本物種目前只見於中南半島上流經柬埔寨、寮國及泰國的九條河流流域的31個地點，已知的分佈範圍從柬埔寨湄公河流域的桔井市 南部至寮國中部凱山豐威漢市的。

本物種見於下列地點：

- 柬埔寨淡水貝列表湄公河沿岸及東北部公河上遊河谷
- 寮國淡水貝列表
- 泰國淡水貝列表東北部

本物種的模式產地位於寮國的Ban Na。

## 形態描述

A detailed account of the anatomy of Neotricula aperta was given by Davis et al. in 1976.

Three strains of Neotricula aperta have been recognized (called α, β and γ), on the basis of shell size and body pigmentation. Although all three strains are susceptible to (γ> > β > α), only the γ-strain is epidemiologically significant.

## 生態學

Neotricula aperta is exclusively 岩生植物 or epixylic (on rotting wood). Neotricula aperta is found only in shallow areas (typically 0.5 to 3 m deep) of the Mekong river and some of its tributaries. The snails are restricted to areas where the current is moderate (around 2 × 103 m3s−1), the water is clear and the bed rock forms (almost flat) platforms where agal aufwuchs is extensive. Such conditions exist only during the 旱季 in the lower Mekong (March to May) and so Neotricula aperta populations persist mostly by recruitment (from eggs laid on stones in the previous year) or re-colonization from other rivers, and transmission of is seasonal. 人口密度 can reach up to 4734 snails per m².

In addition, Neotricula aperta is not known from waters of low 電導率 or pH and is calciphilic; the pH of all Neotricula aperta habitats sampled to date is > 7.5 and the river systems in which the snails are found have always been those draining 喀斯特地形 areas. More recently, Neotricula aperta has been found in the primary streams emerging from karst springs, close to the origins of the streams. The snail Neotricula aperta requires hard water to provide the 鈣 needed for rapid 手性 (腹足綱) growth as populations re-establish in the Mekong river each year following the annual flood.

The ecological requirements of Neotricula aperta indicate that this snail will not become established in the reservoirs or downstream channels of dams in the region and that flooding of habitats by impoundment will eliminate all Neotricula aperta populations from the affected area.

Neotricula aperta grazes the algal epilithon and therefore, unlike species such as Biomphalaria (African vector of other kind of schistosomiasis), cannot survive in areas where sediment is depositing and preventing the growth of the algae upon which it feeds. Indeed, ecological studies of Neotricula aperta have shown that this snail is found only on stones covered with fine sediments and that this species is highly sensitive to 淤積.

## 延伸閱讀

- Attwood S. W. (1994). "Rates of recruitment among populations of the freshwater snail Neotricula aperta (Temcharoen) in North East Thailand". 60(2): 197-200. 10.1093/mollus/60.2.197.
- Attwood S. W. (1995). "The effect of substratum grade on the distribution of the freshwater snail y-Neotricula aperta (Temcharoen), with notes on the sizes of particles ingested". 61(1): 133-138. 10.1093/mollus/61.1.133.
- Attwood S. W., Upatham E. S. & Southgate V. R. (2001). "The detection of Schistosoma mekongi infections in a natural population of Neotricula aperta at Khong Island, Laos, and the control of Mekong schistosomiasis". 67(3): 400-405. 10.1093/mollus/67.3.400.

## 基本資料

- 說明：隸屬新擬釘螺屬的開放新擬釘螺的貝殼特寫
- 說明：Neotricula aperta on a stone
- 學名：Neotricula aperta
- 命名者：(Temcharoen, 1971)
- 異名：Lithoglyphopsis aperta、Neotricula apart（拼寫錯誤）、Tricula aperta