Simocephalus (Simocephalus) mixtus Sars, 1903

Sinev, Artem Y., Dadykin, Ivan A., Umi, Wahidah A. D. & Yusoff, Fatimah M., 2025, New data on Cladocera (Crustacea: Branchiopoda) of Peninsular Malaysia, Zootaxa 5604 (3), pp. 255-284 : 259

publication ID	https://doi.org/10.11646/zootaxa.5604.3.3
publication LSID	lsid:zoobank.org:pub:C8E5E697-223C-45A0-A104-134328213586
DOI	https://doi.org/10.5281/zenodo.15046319
persistent identifier	https://treatment.plazi.org/id/03F2AF08-FFB3-FFC4-C7D2-23F0FD80FCD9
treatment provided by	Plazi (2025-03-16 17:36:46, last updated 2025-03-18 16:18:37)
scientific name	Simocephalus (Simocephalus) mixtus Sars, 1903
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Simocephalus (Simocephalus) mixtus Sars, 1903 View in CoL

Fig. 1F–J View FIGURE 1

Sars 1903b: 174; Orlova-Bienkowskaja 2001: 56–58, Figs. 85–86, Pl. I, II, VI; Rogers et al. 2019: 678, Figs. 16.2.18 I; Korovchinsky et al. 2021b: 156–157, Figs. 46, 9.

Material examined. Four juvenile parthenogenetic females from a pond at the Lake Permai, Ipoh , Perak (4.47728° N, 101.0492° E), 28.01.2018 GoogleMaps .

The species has been recorded in Peninsular Malaysia only once ( Mizuno & Mori 1970), and Idris (1983) did not include it in his monograph. Only juvenile females were present in the studied materials. Juvenile females ( Fig. 1F View FIGURE 1 ) have no distinctive protruding backward dorsal margin, characteristic for large adult females. Studied specimens have typical of subgenus S. ( Simocephalus ) morphology of head ( Fig. 1G View FIGURE 1 ) and postabdomen ( Fig. 1I View FIGURE 1 ), with outer side of postabdominal claw bearing uniform thin setulae ( Fig. 1J View FIGURE 1 ). Studied specimens have the morphology of posterior-dorsal valve prominence characteristic of the species ( Fig. 1H View FIGURE 1 ). The species was recently found in Sabah State, East Malaysia ( Sinev & Yusoff 2018). In South-East Asia, S. mixtus was recorded in the North-East Thailand ( Maiphae et al. 2008) and in Hainan Island (Sinev et al. 2015). For detailed description, see Orlova-Bienkowskaja (2001). Two other species of S. ( Simocephalus ), S. (S.) vetulus (O. F. Muller, 1776) and S. (S.) vetuloides Sars, 1898 were also recorded in South-East Asia ( Korovchinsky 2013), but no morphological descriptions were provided for them. According to Orlova-Bienkowskaja (2001), these species are distributed in temperate regions only, so their presence in the region is doubtful.

References

Idris, B. A. G. (1983) Freshwater zooplankton of Malaysia (Crustacea: Cladocera). Universiti Pertanian Malaysia Press, Serdang, Selangor, 153 pp.

Korovchinsky, N. M. (2013) Cladocera (Crustacea: Branchiopoda) of South-East Asia: history of exploration, taxon richness and notes on zoogeography. Journal of Limnology, 72 (S 2), 109-124. https://doi.org/10.4081/jlimnol.2013.s2.e7

Korovchinsky, N. M., Kotov, A. A., Sinev, A. Y, Neretina, A. N. & Garibian, P. G. (2021 b) The water fleas (Crustacea: Cladocera) of North Eurasia. Vol. 2. KMK, Moscow, 544 pp. [in Russian]

Maiphae, S., Pholpunthin, P. & Dumont, H. J. (2008) Taxon richness and biogeography of the Cladocera (Crustacea: Ctenopoda, Anomopoda) of Thailand. International Journal of Limnology, 44 (1), 33-43. https://doi.org/10.1051/limn:2008021

Mizuno, T. & Mori, S. (1970) Preliminary hydrobiological survey of some Southeast Asian inland waters. Biological Journal of the Linnean Society, 2 (2), 77-118. https://doi.org/10.1111/j.1095-8312.1970.tb01706.x

Orlova-Bienkowskaja, M. Y. (2001) Daphniidae: genus Simocephalus. Guides to the identification of the microinvertebrates of the continental waters of the World 17. Backhuys, Leyden, 130 pp.

Rogers D. C., Kotov A. A., Sinev A. Y. Glagolev S. M., Korovchinsky, N. M., Smirnov, N. N. & Bekker, E. I. (2019) Chapter 16.2. Arthropoda: Class Branchiopoda. In: Rogers, C. D., Thorp, J. H. (Eds.), Thorp and Covich's Freshwater Invertebrates. Vol. 4. Keys to Palaearctic Fauna. Academic Press, London, pp. 643-724. https://doi.org/10.1016/B978-0-12-385024-9.00018-6

Sars, G. O. (1903 b) On the Crustacean fauna of Central Asia. Part II. Appendix. Cladocera. Annuaire de Musee Zoologique de l'Academie des Sciences de St. - Petersbourg, 8, 157-264.

Sinev, A. Y. & Yusoff, F. M. (2018) New data on Cladocera (Crustacea: Branchiopoda) of Sabah State, Borneo Island, Malaysia. Zootaxa, 4438 (2), 362-372. https://doi.org/10.11646/zootaxa.4438.2.10

Figures

FIGURE 1. Simocephalus (Echinocaudus) exspinosus (De Geer, 1778) from pond at Permai Lake, Ipoh, Perak, Malaysia, parthenogenetic female. A, lateral view. B, postabdomen, С, postabdominal claw from outer side. D, basal portion of postabdominal claw from outer side. E, group of pigmented hypoderm cells on valves. Simocephalus (Simocephalus) mixtus Sars, 1903 pond at the Permai Lake, Ipoh, Perak, Malaysia, F, lateral view. G, head. H, posteroventral angle of valves. I, postabdomen. J, basal portion of postabdominal claw from outer side.