The reproductive biology of tropical marine cotylean polyclads is presently poorly known. Reproductive aspects of 16 polyclad species from the family Pseudocerotidae in the genera Acanthozoon, Nymphozoon, Phrikoceros, Pseudobiceros, Pseudoceros, Thysanozoon, and Tytthosoceros from Singapore were documented for the first time. Penis fencing was observed to be just a mating ritual and not necessary for insemination, not always aggressive, and could also result in eventual reciprocal insemination. Results showed that all species underwent similar embryonic developmental stages and hatched as Müller's larvae. Only Pseudoceros concinnus and Pseudoceros laingensis, with mean developmental times of >20 days and mean brood sizes of <1,000 eggs, displayed long‐term parental care. Polyclads producing larger brood sizes had shorter developmental times and only covered their egg masses for about one day. Phrikoceros baibaiye and Pseudobiceros spp. produced egg capsules with pointed opercula, whereas all other species possessed smooth, rounded opercula. All genera hatched with brownish‐orange larvae, except for Pseudoceros spp., which hatched with reddish‐purple larvae regardless of the initial embryo color (either grayish‐yellow or reddish‐purple). These could potentially complement current taxonomic characters in distinguishing polyclad genera and species.

中文翻译：

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在新加坡，一些海洋假性flat扁虫（Platyhelminthes：Rhabditophora：Polycladida）的交配行为，产卵，父母关怀和胚胎发育

目前尚不了解热带海洋Cotylean聚类的生殖生物学。从家庭Pseudocerotidae在属16种的Polyclad生殖方面Acanthozoon，Nymphozoon，Phrikoceros，Pseudobiceros，Pseudoceros，Thysanozoon和Tytthosoceros从新加坡被记录在案的第一次。据观察，阴茎击剑只是一种交配仪式，并不是授精所必需的，并非总是侵略性的，并且还可能导致最终的相互授精。结果表明，所有物种都经历了相似的胚胎发育阶段，并孵化为穆勒幼虫。只有假单胞菌以及平均寿命超过20天且育雏平均卵数小于1,000的laingensis（Pseudoceros laingensis）具有长期的父母关怀。产卵量较大的多囊体的发育时间较短，只覆盖卵约一天。Phrikoceros baibaiye和Pseudobiceros spp。生产的卵囊具尖的盖，而其他所有种类的卵囊均具有光滑的圆形盖。除假单胞菌属（Pseudoceros spp。）以外，所有属均孵化成棕橙色的幼虫，而不论初始胚胎的颜色是什么（灰黄色或淡紫色-紫色），都以淡紫色的幼虫孵化。这些可能会补充目前的分类学特征，以区分多科的属和种。