Table 3 in Genus-level revision of the Alycaeidae (Gastropoda, Cyclophoroidea), with an annotated species catalogue

Table 3. Important traits of Alycaeid genera. GenusProtoconch sculptureTube (R2) lengthShell diameter (mm)Central toothKey traitUnclear relationship withAlycaeussmooth to obliquely striatedvery long (ca. 1/2 whorl)8-155 cusps, broad, central cusp bluntshell very large, R2 ca. half whorl longPincernaChamalycaeussmooth, usually elevatedvariable2-55 cusps, broad, central cusp pointedshell very small to medium sized, usually depressed, R2 of variable lengthPincernaDicharaxsmooth, usually lowvariable1-115-7 cusps, broad, central cusp pointedprotoconch + teleoconch without spiral striaeDioryxsmoothvariable3.5-95-7 cusps, broad, central cusp bluntshell globular or high-spired, sculpture reduced, R3 absentMetalycaeusspirally striated, elevatedvariable3-105 cusps, broad, central cusp pointedprotoconch spirally striatedPincernasmoothvery short to short2.5-65 cusps, broad, central cusp pointedshell very small to medium sized, high spired, R2 shortAlycaeus, Chamalycaeus, StomacosmethisStomacosmethissmoothvery short3-13elongated, usually with 1 central cusp only, or central cusps with 1-2 small cusp at each sidetiangular, colourful shell, R2 very shortPincerna表3 圆口蜗牛科（Alycaeidae）各属的重要性状 本表格各列依次为：属名、胚壳（Protoconch）饰纹、水管（R2）长度、壳直径（mm）、中央齿特征、关键形态特征、与Alycaeus属的亲缘关系。 1. 未标注属名：胚壳饰纹平滑至斜纹状；水管长度极长，约为1/2螺层；壳直径8-15mm；中央齿具5个齿尖，齿板宽阔，中央齿尖钝圆；关键特征为壳体极大，R2长度约为半个螺层；与Pincerna属亲缘关系尚不明确。 2. Chamalycaeus：胚壳平滑，通常具隆起壳饰；水管长度不定；壳直径2-5mm；中央齿具5个齿尖，齿板宽阔，中央齿尖尖锐；关键特征为壳体极小至中等大小，通常呈平扁形，R2长度不定；与Pincerna属亲缘关系尚不明确。 3. Dicharax：胚壳平滑，通常具低矮壳饰；水管长度不定；壳直径1-11mm；中央齿具5-7个齿尖，齿板宽阔，中央齿尖尖锐；关键特征为胚壳与成壳均无螺旋纹；与Dioryx属亲缘关系尚不明确。 4. Dioryx：胚壳平滑；水管长度不定；壳直径3.5-9mm；中央齿具5-7个齿尖，齿板宽阔，中央齿尖钝圆；关键特征为壳体呈球状或高旋形，壳饰退化，无R3结构；与Metalycaeus属亲缘关系尚不明确。 5. Metalycaeus：胚壳具螺旋状纹，通常隆起；水管长度不定；壳直径3-10mm；中央齿具5个齿尖，齿板宽阔，中央齿尖尖锐；关键特征为胚壳具螺旋状纹；与Pincerna属亲缘关系尚不明确。 6. Pincerna：胚壳平滑；水管长度极短至短；壳直径2.5-6mm；中央齿具5个齿尖，齿板宽阔，中央齿尖尖锐；关键特征为壳体极小至中等大小，呈高旋形，R2长度较短；与Alycaeus、Chamalycaeus、Stomacosmethis属亲缘关系尚不明确。 7. Stomacosmethis：胚壳平滑；水管长度极短；壳直径3-13mm；中央齿齿片延长，通常仅具1个中央齿尖，或中央齿尖两侧具1-2枚小齿尖；关键特征为壳体呈三角形、色彩丰富，R2长度极短；与Pincerna属亲缘关系尚不明确。