The valid Species and Distribution of Stingrays (Myliobatiformes: Dasyatidae) in South Sumatran waters, Indonesia

A recent study to providing valid checklist of stingrays species in South Sumatran waters provide 14 species: Brevitrygon heterura, Fluvitrygon kittipongi, Fluvitrygon oxyrhyncha, Fluvitrygon signifier, Fluvitrygon sp ‘musi’ 1, Fluvitrygon sp ‘musi’ 2, Himantura undulata, Himantura uarnak, Maculabatis gerrardi, Pateobatis fai, Pateobatis uarnacoides, Pastinachus ater, Telatrygon biasa and Urogymnus polylepis. Distributional patterns of stingrays in South Sumatran waters are depend on species or (at least) genus level. Stingrays in South Sumatran waters are recorded from of up to more 100 km inland to the coastal zone area. Following IUCN Red List status, 10 species of stingrays are threatened with status Endangered, Vulnerable and Data Deficient; suggest the South Sumatran waters are important habitat for stingrays in Indonesia


Introduction
Indonesia has 4.743 species of fishes, making one the greatest diversity of fish fauna in the world (Froese & Pauly 2018).Many iconic group of fishes known collectively as the 'ray' (Myliobatiformes) occur in Southeast Asia, particuarly in Indonesian waters (Compagno & Roberts 1982, Last et al. 2016b, Kottelat 2013).One of 'ray' is stingrays (family Dasyatidae), groups of small to very large myliobatiform fishes (adults from 22 cm to 260 cm disc wide) and distinguished by the following combination of characters: body variably depressed with a wellformed oval, circular or rhombic disc that fully incorporates head; snout angular to obtuse and sometimes very elongate; nasal curtain well developed, skirt-shaped, rectangular or bilobed; five gill slits; oral papillae usually present on floor of mouth; tail moderately stout to slenderbased and more or less elongated (sometimes very elongate and whip-like); dorsal surface variably covered with dermal denticles, thorns and/or tubercles, smooth to very spiny and often with a median thorn row and/or a median denticle band; no dorsal or caudal fins; 1-4 prominent caudal stings, positioned on tail well posterior to pelvic fins; skin folds variably developed on the ventral and sometimes dorsal midline of tail; dorsal surface plain to strongly patterned, usually darker than ventral surface (Last & Compagno 1999, Last et al. 2016a, Last et al. 2016b, Nelson 2006).
Recent phylogenetic studies, supported by morphological data, have provided evidence that the Dasyatidae is monophyletic and consists of four major subgroups, the subfamilies Dasyatinae, Neotrygoninae, Urogymninae and Hypolophinae; and a morphologically based review of 89 currently recognised species (Last et al., 2016b).Stingrays are highly adapted and successful fishes that occur in marine, estuarine and freshwater habitat in temperate and tropical areas worldwide (Last & Compagno, 1999).In Indonesia, there are 40 valid species of stingrays that occur in main seven faunal regions (Windusari & Iqbal 2018).
South Sumatra province is the largest province in Sumatra where located in the southeastern portion of the island (Whitten et al. 2000).The study of fish diversity had been reported accross the South Sumatran waters (Utomo et al. 2007, Husnah et al. 2008), but the study focus on stingrays were very limited (Iqbal & Yustian 2016, Iqbal et al. 2017, Iqbal et al. 2018).To facilitate on stingrays information in South Sumatran waters, a comprehensive study is required.This paper provide first review on all valid species and distributional records of stingrays in South Sumatran waters.

Materials and Method
Records of stingrays in South Sumatran waters 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); provide an extension to the known distribution of this species and from unpublished data collected by first author.All specimens recorded were mainly from Musi River drainage (the largest and major drainage in South Sumatra) and east coast of Banyuasin.All records included herein were verified; and unconfirmed or ambiguous records were rejected.In addition, three field surveys were conducted in April 2018.

Results And Discussion
There are 14 species of stingrays considered valid occur in South Sumatran waters.The species checklist and localities are presented in table 1. Taxonomy and scientific name follow recent update revision of family Dasyatidae by Last et al. (2016a) and Last et al. (2016b).

Valid species accounts and distributional records of stingrays in South Sumatran waters
This section discusses details all stingrays species that occur in South Sumatran waters.Synonym and global distribution of each species are given.Distributional patterns of stingrays in South Sumatran waters are depend on species or (at least) genus level.Stingrays in South Sumatran waters are recorded from of up to more 100 km inland to the coastal zone area (Figure 1-3).
Fluvitrygon sp 'musi' 1. Synonym: None.Distribution: Possibly new undescribed species (Peter Last, Pers.Comm).It is look like very limited in Musi River.This species differ from other Fluvitrygon by dorsal plain colour, no white edge at dorsal side and elongated snout (Figure 3e).
Fluvitrygon sp 'musi' 2. Synonym: None.Distribution: Possibly new undescribed species (Peter Last, Pers.Comm).It is look like very limited in Musi River.This species differ from other Fluvitrygon by pale dorsal plain colour, lacking of white edge at dorsal side and very sharp elongated snout (Figure 3f).

The importance of South Sumatran waters for stingrays habitat
The occurence of 14 species indicate that South Suma Sumatran waters are important habitat for stingrays of family Dasyatidae.Following IUCN Red List status, the status of stingrays in South Sumatran status covering from Endangered, Vulnerable, Data Deficient, Least Concern and not evaluated (IUCN 2018).The occurence of threatened species in South Sumatran waters suggest the importance of area as habitat for endangered species of stingrays in Indonesia.Four species under Endangered status are Fluvitrygon kittipongi, Fluvitrygon oxyrhyncha, Fluvitrygon signifer and Urogymnus polylepis (Table 1).All of them are freshwater stingrays.Two unidentified of from Musi River, tentatively identified as Fluvitrygon sp 'musi' 1 and Fluvitrygon sp 'musi' 2, probably represent new undescribed species (Peter Last, Pers.Comm).  in South Sumatran waters under this category: Himantura undulata, Himantura uarnak, Maculabatis gerrardi, Pateobatis fai and Pateobatis uarnacoides.Almost of these stingrays lives in the coastal area (Last et al., 2016b), and they are found in coastal zone of Banyuasin.Only one species found into brackish water, Maculabatis gerrardi (Table 1, Figure 2 and Figure 4g).One species, Brevitrygon heterura, is species under Data Deficient of IUCN status.This species is relatively common in South Sumatran waters, found in the coastal zone of Banyuasin.There are two species considered as Least Concern, the Pastinachus ater and Telatrygon biasa.Locally, the Telatrygon biasa is a relatively common and scattered in the east coast of Banyuasin, while the Pastinachus ater is relatively rarer, where only one record can be confirmed.Another species of Pastinachus, Pastinachus solocirostris is likely to be found in the Musi River or Banyuasin coast, and the possibility of misidentification between these two species is possible.Pastinachus solocirostris is a new species that was described in 2005, and distribute in coastal waters of western Indonesia (Last et al. 2005).
Review on distribution of stingrays in the South Sumatran waters suggest that the Musi River in Palembang City is important habitat for at least three freshwater species that have Endangered status: Fluvitrygon kittipongi, Fluvitrygon signifer and Urogymnus polylepis (Table 1, Figure 1-3).This number will increase if two unidentified species of Fluvitrygon (Fluvitrygon sp 'musi' 1 and Fluvitrygon sp 'musi' 2) can be clarified its taxonomic status, so that the number of Endangered species will increase.As urban area, conservation proposals for endangered stingrays species in Musi River of Palembang city require specific strategies, compared to conservation approach in conservation areas such as Wildlife Reserve of National Park.Urban area with dense human population such as Palembang are sometimes considered unimportant for the protection of a species conservation habitat.The case studies shown by Trzyna (2014) in several major cities in the world show that many urban areas with dense settlements become habitat for rare flora fauna, and are important in supporting the life of the people in the city itself.Musi River in Palembang City which is the capital city of South Sumatra Province has a dense residential population, surrounded by many big factories and crowded human activities.Proposing the Musi River area in Palembang City as a conservation area is something very unlikely.Few strategies that can be done to protecting stingrays species in Musi River since stingrays are not yet protected by the Law of the Republic of Indonesia (Noerdjito & Maryanto 2001).Spreading banners or bulletin boards on the banks of the well-visited by many people in Musi River with a message not to capture or relinquish stingrays caught will help wider community to know that stingrays are groups of fish that are particularly vulnerable to extinction.

Conclusion
A total of 14 species from eight families of stingrays was recorded in South Sumatran water.Following IUCN Red List status, the status of stingrays in South Sumatran status covering from Endangered, Vulnerable, Data Deficient, Least Concern and not evaluated.The occurence of threatened species in South Sumatran waters suggest the importance of area as habitat for endangered species of stingrays in Indonesia.It is surprisingly that three freshwater Endangered stingrays (Fluvitrygon kittipongi, Fluvitrygon signifer and Urogymnus polylepis) found in Musi River of Palembang city.As urban area, conservation of Endangered stingrays species in Musi River of Palembang city is complicated and require specific strategies.

Acknowledgement
We would like to thank Dr. Yuanita Windusari, Dr. Laila Hanum and Pak Doni Setiawan, M.Si for facilitating us conducting field surveys in Musi River and east coast of Banyuasin.First author thank Dr. Zazili Hanafiah, Dr. Sarno and Dr. Arum Setiawan for their critical reviews on this study.

Figure 2 .
Figure 2. Map of distributional records of Genus Himantura, Maculabatis and Pateobatis in South Sumatran waters.Solid circle is Himantura undulata, open square is Himantura uarnak, open star is Maculabatis gerrardi, solid triangle is Pateobatis fai and solid square is Pateobatis uarnocoides.

Figure 3 .
Figure 3. Map of distributional records of Genus Pastinachus, Telatrygon and Urogymnus in South Sumatran waters.Open star is Pastinachus ater, solid triangle is Telatrygon biasa and solid circle is Urogymnus polylepis.