Trachemys scripta ( Thunberg in Schoepff , 1792)

Figueroa, Alex, Low, Martyn E. Y. & Lim, Kelvin K. P., 2023, Singapore’s herpetofauna: updated and annotated checklist, history, conservation, and distribution, Zootaxa 5287 (1), pp. 1-378 : 72-74

Trachemys scripta ( Thunberg in Schoepff, 1792) — Non-native; Established.

Testudo scripta Thunberg in Schoepff, 1792 [in 1792–1801]: 16, 17, pl. 3, fig. 2. Holotype: UUZM 7455 , previously considered lost and never given an original accession number, was rediscovered by Rhodin & Carr (2009: 12); specimen illustrated in figs. 4, 5 pl.3 labeled “Test. scripta Thunb.” (Schoepff 1792). Type locality: “[p]atria … ignota sunt” (= Not known); later restricted to “Charleston, South Carolina ”, USA by Schmidt (1953: 102).

Red-eared Slider

( Figure 8G ; Punggol Point Jetty)

Singapore records.

Pseudemys scripta elegans —K. Lim, 1988a: 5 (Botanical Gardens; East Coast Park; MacRitchie Reservoir; Pandan Canal; Seaside Park [Siglap]).—K. Lim & F. Lim, 1988c: 77 (Botanic Gardens).—K. Lim & F. Lim, 1989: 3 ( Woodlands Town Garden).— K. Lim, 1989b: 21 (Sungai Loyang Canal; Upper Peirce Reservoir).

Trachemys scripta elegans —K. Lim, 1989e: 39 (Bedok Reservoir; Marina South).—K. Lim, 1989h: 65 (Sime Road Forest).—K. Lim, 1990a: 11 (Marina South; Roller Skating Rink [Sentosa]; Sime Road [SRF]).—K.K.P. Lim & L.M. Chou, 1990: 56.—K.P. & Subharaj, 1991d: 4 (Marina East).— K.K.P. Lim & F.L.K. Lim, 1992: 126, 151.—K.K.P. Lim & Subharaj, 1992: 9 (Bedok Canal; East Coast Park; Lower Peirce Forest [LP]; Lower Peirce Reservoir; MacRitchie Reservoir; Marina East; Marina South; Sime Road Forest).—P.K.L. Ng, 1992a: 142.—P.K.L. Ng, 1992b: 142.—W.K. Tan, 1992: 28.—Wee, 1992: 74 (Lower Peirce Reservoir Park).—K.K.P. Lim, 1993b: 3 (Bukit Timah Hill; Sime Road Forest).—P.K.L. Ng et al., 1993: 20.—L.M. Chou et al., 1994: 105.— K.K.P. Lim & Subaraj, 1994: 7 (Sungei Buloh Nature Park [= SBWR]).—R. Subaraj, 1994: 14 (Sime Road Forest; Upper Peirce West [UPWF]).—R.C.H. Teo & Rajathurai, 1997: 393 (Botanic Gardens).—Iskandar, 2000: 144.—B.P.L. Goh et al., 2002: 143.—T.Y. Goh & O’Riordan, 2007: 97, 98.—Ramsay et al., 2007: 165.—H.T.W. Tan et al., 2007: 140.—N. Baker & K.P. Lim, 2008: 125, 165.—T.H. Ng & K.K.P. Lim, 2008: 119, 123 (Pulau Tekong; Upper Seletar).—P.K.A. Ng, 2009: 1–257 (Bedok Reservoir, Bishan Park, Botanic Gardens, Bukit Batok Nature Park, Bukit Batok Town Park, Bukit Panjang Park, Changi Beach, East Coast Park, Jurong Lake, Kandang Kerbau Hospital, Kranji Reservoir, Labrador Nature Reserve, Lower Peirce Reservoir, Lower Seletar Reservoir, MacRitchie Reservoir, Marina City Park, Night Safari, Pandan Reservoir, Punggol Park, St. John’s Island, Sungei Buloh Wetland Reserve, Sungei Kangkar, Sungei Punggol, Sungei Serangoon, Sungei Tampines, Sungei Tengah, Tampines Quarry, Upper Peirce Reservoir, Upper Seletar Reservoir, West Coast Park, Woodlands Town Garden).— Das, 2010: 174.—D.C.J. Yeo & C.S.W. Chia, 2010: 35.—D.C.J. Yeo et al., 2010: 160.—H.T.W. Tan et al., 2010: 183–184, 251.—P.K.L. Ng et al., 2011: 480.—H.T.W. & K.K.P. Lim, 2011: 196.—D.C.J. Yeo et al., 2011: 102, 105.—N. Baker & K.P. Lim, 2012: 15, 125, 165.—K.K.P. Lim, 2013d: 119.—K.S. Chua, 2014: 262 (Hougang Avenue 10]).—K.W.C. Leong & K.K.P. Lim, 2014: 315–316 (Mountbatten).—K.K.P. Lim, 2014d: 225 (Botanic Gardens).—D.L. Yong et al., 2014: 203.—N. Baker, 2015a: 25.—N. Baker, 2015b: 56 (MacRitchie Reservoir).—H.H. Tan, 2015: 99, 100 (Botanic Gardens).—Wijedasa, 2015: 180 (Botanic Gardens).—K.K.P. Lim et al., 2016: 176 (Pulau Tekong).—H.H. Tan, 2016a: 122 (Kent Ridge Park).—H.H. Tan, 2019: 160, 162 (Gardens by the Bay).—R.C.H. Teo & Thomas, 2019: 155, 179 (Catchment Pond [BTNR], after R.C.H. Teo & Rajathurai, 1997; Hindhede Quarry).—H.T.W. Tan et al., 2019: 135 (Kent Ridge Park).—Allain & Goodman, 2020: 217, 218 ( Singapore Botanic Gardens [Eco Lake]).—TTWG, 2021: 164.—E. Chong & D.C.J. Yeo, 2022: 1 (Seletar Park Connector).—Pocklington, 2022: 1.

Trachemys scripta —Chan-ard et al., 1999: 40.—B.L. Lim & Das, 1999: 96.— Auliya, 2007: 38–39.— R. Subaraj, 2015: 9, 32, 43, 46, 47 (Night Safari; Singapore Zoo; Upper Seletar Peninsula [= USNF]).—S. Subaraj, 2015: 3, 6 ( Singapore Zoo; Upper Seletar Peninsula [= USNF]).

Trachemys scriptaelegans [sic]— Anonymous, 2003: 92 (Sungei Buloh Wetland Reserve).

“Red-eared Terrapins”— Anonymous, 2014: 52 ( Singapore Polytechnic).

Trachemy [ sic] scripta elegans — H.H. Tan & S. Tay, 2019: 136 (Kallang River).

Remarks. Being the world’s most popular turtle in the pet trade, and with over 52 million individuals exported from the United States to foreign markets between 1989 and 1997 ( Global Invasive Species Database 2019b), T. scripta is now considered one of IUCN’s 100 World’s Worst Invasive Species ( Lowe et al. 2004). Since the first exports, individuals of T. scripta have been released by their owners worldwide, and has become invasive in about 64 countries (TTWG 2021; Global Invasive Species Database 2019b). To this day, T. scripta remains popular in the pet trade and individuals are continually being released. In Singapore, T. scripta is believed to have been introduced as early as the 1960s, with imports reaching up to 270,000 hatchlings per year (Ng & Lim 2010) and exceeding more than 1.2 million individuals in 2006 and 2007 (Ng 2009). A large number of the imports were also used to supplement turtle meat consumption of Pelodiscus sinensis (see Ng 2009). Trachemys scripta is now Singapore’s most common turtle species and is found in each and every waterbody throughout the entire country ( Baker & Lim 2012), including mangroves (A. Figueroa pers. obs.). Population estimates at Eco-Lake in SBG is about 392 individuals and 562 individuals at LPR (Ng 2009). Undoubtedly T. scripta is established in Singapore, and no substantial observations on reproduction exist aside from some turtles seen nesting at various locations (Ng 2009), many captured female turtles with developing follicles and oviductal eggs (Ng 2009), 16 hatchlings reported from eggs that were collected at a Dakota housing estate ( Leong & Lim 2014), and 11 hatchlings excavated from under 10 cm of soil at Seletar Park Connector on 14 July 2021 ( Chong & Yeo, 2022). Nonetheless, as T. scripta is still sold in large numbers in Singapore, released individuals certainly contribute greatly to Singapore’s populations. Due to population sizes, distribution, and ecological similarities to native species, T. scripta is considered invasive in Singapore (Ng 2009).

Occurrence. Ubiquitous. Common.

Singapore conservation status. Not Applicable.

Conservation priority. None, non-native species.

IUCN conservation status. Least Concern [2011].

LKCNHM & NHMUK Museum specimens. Singapore (no locality) : ZRC.2.2504– ZRC.2.2506 (24-Jan-1987) ; Cluny Road: ZRC.2.2553 (24-Mar-1990) , ZRC.2.2587 (04-Apr-1990) .

Additional Singapore museum specimens. No specimens.

Singapore localities. Bedok Canal—Bedok Reservoir—Bishan Park—Bukit Batok Nature Park—Bukit Batok Town Park—Bukit Panjang Park—Bukit Timah Nature Reserve—Changi Beach—Cluny Road—East Coast Park—Gardens by the Bay—Hindhede Quarry—Hougang Avenue 10—Jurong Lake—Kallang River—Kandang Kerbau Hospital—Kent Ridge Park—Kranji Reservoir—Labrador Nature Reserve— Lower Peirce—Lower Peirce Forest—Lower Peirce Reservoir—Lower Seletar Reservoir—MacRitchie Reservoir— Marina City Park —Marina East—Marina South—Mountbatten—Night Safari—Pandan Canal—Pandan Reservoir—Pulau Tekong—Punggol Park—Punggol Point Jetty—Seletar Park Connector— Sentosa—Siglap—Sime Road Forest—Singapore Botanic Gardens—Singapore Polytechnic—Singapore Zoo—Sungei Buloh Wetland Reserve—Saint John’s Island—Sungei Kangkar—Sungei Loyang Canal— Sungei Punggol—Sungei Serangoon—Sungei Tengah—Sungei Tampines—Tampines Quarry—Upper Peirce Reservoir—Upper Peirce West Forest—Upper Seletar North Forest—Upper Seletar Reservoir— West Coast Park—Woodlands Town Garden.

Figures

FIGURE 8. A) Caretta caretta, B) Chelonia mydas, C) Eretmochelys imbricata, D) Lepidochelys olivacea, E) Dermochelys coriacea, F) Dermochelys coriacea, G) Trachemys scripta, and H) Batagur borneoensis. Photographs by: Halvard Aas Midtun [A], Marcus A.H. Chua [B], Karenne Tun [C], Ashesh Rathor [D], Tan Heok Hui [E], Alastair Rae [F], Holly Siow [G], and Kelvin K.P. Lim [H].