Ichthyol. Explor. Freshwaters, Vol. 28, No. 2, pp. 171-176, 3 figs., 1 tab., January 2018
© 2018 by Verlag Dr. Friedrich Pfeil, München, Germany – ISSN 0936-9902

New data on the distribution of the endangered white-edge freshwater whipray Fluvitrygon signifer (Chondrichthyes: Dasyatidae)

Muhammad Iqbal*, Doni Setiawan** and Ajiman***
* Conservation Biology Program, Faculty of Science, Sriwijaya University, Jalan Padang Selasa 524, Palembang, Sumatera Selatan 30129, Indonesia. E-mail: kpbsos26@yahoo.com (corresponding author)
** Department of Biology, Faculty of Science, Sriwijaya University, Jalan Raya Palembang-Prabumulih km 32, Indralaya, Sumatera Selatan 30662, Indonesia. E-mail: doniunsri@gmail.com
*** Community of Conservation, Department of Biology, Faculty of Science, Sriwijaya University, Jalan Raya Palembang-Prabumulih km 32, Indralaya, Sumatera Selatan 30662, Indonesia. E-mail: ajimanbrm@gmail.com

Stingrays (family Dasyatidae) are highly adapted and successful fishes that occur in marine, estuarine and freshwater habitat in temperate and tropical areas worldwide (Last & Compagno, 1999). Only a small proportion of dasyatid rays occur in freshwater, and include obligate fresh-water species (those found only in freshwater) and euryhaline species (those that move between fresh and salt water) (Last et al., 2016b). Rays are well known for their inherent vulnerability to population decline and collapse
(Lucifora et al., 2015). Many of stingrays species have been evaluated for extinction risk, due to their occurrence in restricted habitats and intense fishing (Last et al., 2016b).



The white-edge freshwater whipray Fluvitrygon signifer is one of 14 species of stingrays of the family Dasyatidae that are known
to enter or to live permanently in freshwaters in Southeast Asia [Brevitrygon imbricata, Fluvitrygon kittipongi, F. oxyrhynchus, F. signifer, Hemitrygon laosensis, Himantura uarnak, Makararaja chind-winensis, Megatrygon microps, Pateobatis bleekeri, Urogymnus granulatus, U. polylepis, Pastinachus ater, P. solocirostris, P. stellurostris] (Kottelat, 2013; Last et al., 2016b). Fluvitrygon signifer was previously known as Himantura signifer (Compagno & Roberts, 1982; Last & Compagno, 1999), until the reclassification by Last et al. (2016a). It was originally described from the Kapuas River (west Kalimantan, Indonesia) by Compagno & Roberts (1982). Subsequently, other freshwater ray records from Indragiri River (Sumatra, Indonesia), Perak River (western Peninsular Malaysia), and Chao Phraya River (Thailand) were examined and found to be conspecific with F. signifer (Compagno & Roberts, 1982). To date, F. signifer is only known to occur in these four drainages and based on 10 specimens (Compagno, 2016), contributing to its assessment as Endangered (EN).The occurrence of Fluvitrygon signifer in Sumatra is based on records from the Indragiri River (00°S), but it has never been reported from the Musi River drainage (04 °S) or elsewhere in Sumatra (Compagno, 2016; Last et al., 2016b). Records of Fluvitrygon signifer in Musi River drainage between 2012 and 2017 were obtained from local social media (mainly Facebook group of local anglers in South Sumatra province) and internet supported with photographs or other evidence (e.g. location, habitat type, morphology and description from anglers); and provide an exten-