Turbellarian taxonomic database

Abstract / Notes

A new species, Miroplana shenzhensis Wang et Yu, sp. nov. of the genus Miroplana (Platyhelminthes, Tricladida, Uteriporidae) was described in this paper. Considering only 2 species of genus Miroplana were recorded in the world, there is relative controversy about the diagnostic characteristics of the genus.In this paper, we studied the morphology, generation, food habit, behavious, histology of the new species of genus Miroplana, Miroplana shenzhensis Wang and Yu sp. nov., and gave a berief discusssion of its habit and ecology significane.

Material. Holotype, PLA-0060, upstream of Huizhou section ofDongjiang river(23°09?01.97? N, 114°22?28.97? E), Guangdong Province, China, December, 2012. Paratypes, PLA-0061 – PLA-0068; the same date and locality as holotype. All the type specimens were collected by LU Yan-Hong (a student of Shenzhen University) and deposited in National Zoological Museum, Institute of Zoology, Chinese Academy of Sciences, Beichen West Road, Chaoyang District, Beijing 100101, China.
Description (Figs 1 -21). The body length is 1500 -2000 ?m and width is 250 -350 ?m, 3 black bands over the dorsal body surface.The specimens have a pair of dark black V-shape eyes located in the frontal band. The penis and the bursa canal arrange ventrally in both sides and between 2 bands in the posterior of the body. There are 2 pairs of testes. The vas deferens reaches out from interior of the frontal pair of testes, along the ventral and lateral pharynx. It finally joins with the other vas deferens of the posterior pair of testes and opens into the seminal vesicle of the basal penis. The penis located in rear of pharynx, and it is enstrophe, with sclerotic spines(subtriangular, 7 -10 ?m) on the surface of whole penis. A pair of ovaries is located in the frontal pair of testes. The oviducts are located inside of the vas deferens, extending to the end of bursa canal which connects with the bursa copulatrix. In the same place there is one tubule connecting with genital atrium. The bursa canal is located in the right side of the penis, opening to male atrium on the basal penis.
Habitat. The new species were found in Huizhou section of Dongjiang river(23°09?01.97? N, 114°22?28.97? E)in Guangdong Province, China, which is Shenzhen and Hongkong city's water supply source and 220km away from the estuary. They have been collected from both freshwater and brackish water. In addition, there were other distributions like: stream of Zengcheng Guangzhou(23°29?15.58?N, 113°47?04.76?E)(attitude 70m); Shenzhen Reservoir (22°36?13.99?N, 114°10?10.57?E)(attitude 33m); in brackish water, Dongchong Stream in Shenzhen(22°29?46.81?N, 114°34?03.32?E)and Hengqin Island in Zhuhai(22°07?22.43?N, 113°28?22.06?E)(salinity 5 ‰).
Etymology. The species was named after the Shenzhen city in Guangdong Province, China.
Remarks. The external features of Miroplana trifasciata(Kato, 1931)and Miroplana shenzhensis sp. nov. are relatively similar. The former’s penis and bursa canal are in tandem arrangement, and there are sclerotic spines (3-5?m) present at the end of the penis. The bursa canal is open to the genital atrium independently, while two oviducts are located in outer side of the vas deferens, leading to terminal branches of bursa canal. The penis and bursa canal of Miroplana shenzhensis sp. nov. arrange ventrally in both sides of the body, with sclerotic spines(subtriangular, 7-10 ?m) densely covered on the surface of the penis. The bursa canal is open to the male atrium, which is in the base of the penis. The oviduct is located in the median of the ejaculatory duct, and it leads to the end of the bursa canal. Consequently, there are notable differences between Miroplana trifasciata and Miroplana shenzhensis sp. nov..
Biological characteristics. Miroplana shenzhensis sp. nov. swims very fast and it prefers feeding on Daphnia. The planaria which was collect from the brackish water can adapt tothe freshwater in the laboratory. When mating, the ventral gonopores sticks to each other and their heads separate in the same direction (like Y -shape) or in the reverse direction. The fertilized egg is spherical reddish-brown, and the diameter is 250 -300?m. Incubation lasts 7.3±1.22d(n=12). On the sixth day the embryo can germinate eyespots and eggshell dented. The larvae number that each egg hatched are 7.8±1.41(n=12). There is no band on the back of the larvae that just emerges from its shell. On the third day, the first black band appeares on the middle of the back, and on the fifth day, this band can divide into 2 bands. On the fourteenth day (several days after the appearance of the bands on the end of the specimen), the reproductory organs can be fully developed.
Discussion. The majority of Miroplana shenzhensis sp. nov. are distributed in drinking water source of cities, and minority of them are in the brackish water which are located in the stream and emptied into the sea. No apparent differences in morphology have been found in species of different habitats and thus they are considered to be the same species in this paper. According to nearly 3 years of field investigation by our research group, Miroplana shenzhensis sp. nov. is considered can be used as an indicator species to tell whether water resources and environment have been polluted. Miroplana shenzhensis sp. nov. belongs to Maricola of Tricladida. However, there is no molecular research data about them. In this paper, Miroplana shenzhensis sp. nov. is speculated more similar to Continenticola of Tricladida. The habitat genus of Miroplana needs to be studied and discussed further more.

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