Fig 1 - uploaded by Chee Kong Chim
Content may be subject to copyright.
Pseudoceros indicus. A, Individual with everted penis; B, Penis fencing in a mating pair; C, Insemination at the posterior region of another flatworm by hypodermic injection; D, Sperm bundles on the dorsal surface; E, Sperm bundle on the posterior ventral surface; F, Detail of sperm bundle. Scale bars = 5 mm (A-E); 1.5 mm (F).
Source publication
The reproductive behaviour of a pair of Pseudoceros indicus from Singapore was observed in the laboratory. Pre-copulatory behaviour included penis fencing, i.e., using their extensively everted penis to stab each other on any part of the body while avoiding being inseminated. However, successful injection resulted in the transfer of sperm in the fo...
Contexts in source publication
Context 1
... during both day and night. Penis fencing between the pair of flatworms was first observed about two hours after field collection. A total of six penis-fencing sessions were observed before the first oviposition event (Table 1). Penis fencing began when both flatworms had their penis everted, which can be seen clearly from the antero-ventral view (Fig. 1A). During each bout, both individuals tried to strike each other while avoiding being stabbed. Penis fencing (Fig. 1B) and insemination ( Fig. 1C) occurred simultaneously and the whole process lasted from 10 minutes to more than an hour. Hypodermic inseminations occurred on both dorsal ( Fig. 1D) and ventral ( Fig. 1E) surfaces of the ...
Context 2
... collection. A total of six penis-fencing sessions were observed before the first oviposition event (Table 1). Penis fencing began when both flatworms had their penis everted, which can be seen clearly from the antero-ventral view (Fig. 1A). During each bout, both individuals tried to strike each other while avoiding being stabbed. Penis fencing (Fig. 1B) and insemination ( Fig. 1C) occurred simultaneously and the whole process lasted from 10 minutes to more than an hour. Hypodermic inseminations occurred on both dorsal ( Fig. 1D) and ventral ( Fig. 1E) surfaces of the body. Sperm was transferred in single or multiple ball-shaped spermatophores (Fig. 1F). Both flatworms received sperm ...
Context 3
... penis-fencing sessions were observed before the first oviposition event (Table 1). Penis fencing began when both flatworms had their penis everted, which can be seen clearly from the antero-ventral view (Fig. 1A). During each bout, both individuals tried to strike each other while avoiding being stabbed. Penis fencing (Fig. 1B) and insemination ( Fig. 1C) occurred simultaneously and the whole process lasted from 10 minutes to more than an hour. Hypodermic inseminations occurred on both dorsal ( Fig. 1D) and ventral ( Fig. 1E) surfaces of the body. Sperm was transferred in single or multiple ball-shaped spermatophores (Fig. 1F). Both flatworms received sperm after each bout of penis ...
Context 4
... can be seen clearly from the antero-ventral view (Fig. 1A). During each bout, both individuals tried to strike each other while avoiding being stabbed. Penis fencing (Fig. 1B) and insemination ( Fig. 1C) occurred simultaneously and the whole process lasted from 10 minutes to more than an hour. Hypodermic inseminations occurred on both dorsal ( Fig. 1D) and ventral ( Fig. 1E) surfaces of the body. Sperm was transferred in single or multiple ball-shaped spermatophores (Fig. 1F). Both flatworms received sperm after each bout of penis fencing. Sperm bundles spread across the body as white streaks, and were absorbed within a day ( Fig. ...
Context 5
... from the antero-ventral view (Fig. 1A). During each bout, both individuals tried to strike each other while avoiding being stabbed. Penis fencing (Fig. 1B) and insemination ( Fig. 1C) occurred simultaneously and the whole process lasted from 10 minutes to more than an hour. Hypodermic inseminations occurred on both dorsal ( Fig. 1D) and ventral ( Fig. 1E) surfaces of the body. Sperm was transferred in single or multiple ball-shaped spermatophores (Fig. 1F). Both flatworms received sperm after each bout of penis fencing. Sperm bundles spread across the body as white streaks, and were absorbed within a day ( Fig. ...
Context 6
... while avoiding being stabbed. Penis fencing (Fig. 1B) and insemination ( Fig. 1C) occurred simultaneously and the whole process lasted from 10 minutes to more than an hour. Hypodermic inseminations occurred on both dorsal ( Fig. 1D) and ventral ( Fig. 1E) surfaces of the body. Sperm was transferred in single or multiple ball-shaped spermatophores (Fig. 1F). Both flatworms received sperm after each bout of penis fencing. Sperm bundles spread across the body as white streaks, and were absorbed within a day ( Fig. ...
Citations
... zebra, Pleioplana atomata, and Stylochus pygmaeus (Gammoudi & Tekaya, 2017;Merory & Newman, 2005;Rawlinson, Bolaños, Liana, & Litvaitis, 2008), whereas to date, displays such as these have been documented in only one cotylean species, Pseudoceros indicus (Chim et al., 2015). ...
... In terms of mating, polyclads are simultaneous hermaphrodites, and each individual possesses both male and female reproductive systems. Precopulatory behavior of penis fencing, in which the flatworms use their extensively everted penis to stab one another on any part of the body while trying to avoid being inseminated, has been documented in two species from the family Pseudocerotidae, namely Pseudoceros bifurcus (Michiels & Newman, 1998) and P. indicus (Chim et al., 2015). Other than these publications, there have been only brief descriptions of the mating behaviors of Thysanozoon nigropapillosum (Jie, Kuo, & Mok, 2014) and Pseudoceros magangensis (Jie, Gan, Chen, & Kuo, 2016). ...
... A third larva type, Kato's larvae, has also been reported, in which larvae can metamorphose inside the egg capsule (Kato, 1940) but can also hatch as free-swimming larvae (Martín-Durán & Egger, 2012). In cotyleans, most undergo indirect development and hatch as Müller's larvae (Bolaños, 2008;Chim et al., 2015;Lang, 1884;Prudhoe, 1985;Rawlinson, 2014). ...
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.
... It is without surprise that the polyclad diversity in the country is high. However, only until recently, this group of almost exclusively marine, free-living flatworms belonging to the phylum Platyhelminthes, clade Rhabditophora Ehlers (1986), has received some attention (Chim et al., 2015;Bolaños et al., 2016;Ong et al., 2018). Previously, the only polyclad records for Singapore were by Collingwood (1876) and Laidlaw (1903), in which eight species were described. ...
... However, the two similarly coloured and patterned species, P. concinnus and P. indicus, require molecular analyses to validate the importance of the longitudinal median line as a diagnostic character for P. concinnus. (Newman & Schupp, 2002); Indonesia and Maldives (Newman & Cannon, 2005); Singapore (Chim et al., 2015). ...
... The reproductive behaviour and embryonic development of P. indicus were recently examined by Chim et al. (2015). This study indicates the presence of P. indicus in Singapore, and therefore, it is not reported here as a new record for the country. ...
... To date, the knowledge about Singaporean polyclads is limited to the published records of Collingwood (1876), Laidlaw (1903), and Chim et al. (2015). Additional species have been informally documented (Tan, 2008) and other occasional photographic records are known for the country (Newman & Cannon, 2005). ...
A detailed taxonomic report of 16 species of polyclad flatworms found in Singapore during the Comprehensive Marine Biodiversity Survey is presented. Representatives of the genera Nymphozoon, Phrikoceros, Pseudobiceros, Pseudoceros, and Tytthosoceros are described using high quality photographs, extended descriptions with information on colour variation, together with a compilation of geographic distribution based on the known records. All species belong to the family Pseudocerotidae and all represent new records for Singapore except Pseudobiceros bedfordi, P. hancockanus, and Pseudoceros indicus. Identifications were based mainly on external morphological characters, with particular emphasis on their living colours and patterns. The genus Nymphozoon is re-described, and a new combination Nymphozoon orsaki nov. comb. is established as it is shown that the monotypic genus Maiazoon is a junior synonym of Nymphozoon. Emended diagnoses for Pseudobiceros damawan, P. hancockanus, and Pseudoceros laingensis are also included. Pseudoceros caeruleocinctus is reinstated as a valid species and is recognised as a senior synonym of Pseudoceros sapphirinus, while Pseudobiceros uniarborensis is identified as a junior synonym of Pseudobiceros hancockanus. This study shows that polyclads are significantly diverse in Singapore, and also highlights the need for further studies using both morphological and molecular data to confirm their identities.
