The reproductive biology and diet of the longtail butterfly ray Gymnura poecilura is described based on 630 specimens (N = 377 females and 253 males). The mean disc width (WD) of females and males was 576.7 mm (range = 190–920 mm) and 416.3 mm (230–550 mm), respectively. Sexual dimorphism in size was seen, with the maximum size of males being only 60% of the maximum female size. The disc widths at 50% maturity (WD50) were estimated to be 506.5 mm (females) and 435.9 mm (males). The mean uterine fecundity was 3.3 (range = 1–8). The size at birth was between 190 and 220 mm WD. Year-round reproduction was indicated, due to the presence of mature males and gravid females throughout the year, neonates in multiple months and large variations in embryo size within months. Feeding intensity increased with body size. Fish accounted for 80.9% of the diet (Index of Relative Importance, IRI), followed by crustaceans (18.9%) and molluscs. The species was found to be a specialized feeder.

中文翻译：

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孟加拉湾西部长尾蝴蝶 Gymnura poecilura (Shaw, 1804) 的生殖生物学和饮食

长尾蝶鳐的生殖生物学和饮食鲶鱼基于 630 个样本（N = 377 名女性和 253 名男性）进行了描述。平均盘宽 (WD）的女性和男性分别为 576.7 毫米（范围 = 190-920 毫米）和 416.3 毫米（230-550 毫米）。可见大小两性异形，雄性的最大尺寸仅为雌性最大尺寸的 60%。成熟度 50% 时的圆盘宽度 (WD50) 估计为 506.5 毫米（女性）和 435.9 毫米（男性）。平均子宫生育力为 3.3（范围 = 1-8）。出生时的尺寸在 190 到 220 毫米之间WD. 由于全年都有成熟的雄性和怀孕的雌性，多个月的新生儿和几个月内胚胎大小的巨大变化，表明全年繁殖。摄食强度随体型增大而增加。鱼类占饮食的 80.9%（相对重要性指数，IRI），其次是甲壳类动物（18.9%）和软体动物。该物种被发现是一种特殊的饲养者。