Limnonectes plicatellus (Stoliczka, 1873) — Native.

Rana plicatella Stoliczka, 1873: 112, 116–117, pl. 11, fig. 1. Holotype: ZSI 9542, according to Chanda et al. (2000: 110). Type locality: “either Penang itself or on the opposite coast of the Wellesley Province”, [= Penang and Seberang Perai], Peninsular Malaysia.

Rhinoceros Frog (Figure 5B; Upper Seletar Reservoir Park)

Singapore records.

Rana plicatella —A.L. Butler, 1903: 197 (Bukit Timah [BTNR]).— Boulenger, 1912: 231 (Bukit Timah [BTNR]).— Bourret, 1942: 272.—Taylor, 1962: 404.—K. Lim, 1988b: 6 (Bukit Timah Nature Reserve).—K. Lim, 1989g: 41 (Jungle Fall Valley [BTNR]).—K. Lim, 1990b: 13 (Nee Soon Swamp Forest).—K.K.P. Lim & L.M. Chou, 1990: 56.—K.K.P. Lim & C.M. Yang, 1991: 226.— K.K.P. Lim & F.L.K. Lim, 1992: 36, 144.—P.K.L. Ng & K.K.P. Lim, 1992: 260 (Nee Soon Swamp Forest).—K.K.P. Lim, 1993b: 4 (Cave Path [BTNR]).—L.M. Chou et al., 1994: 93.—K.K.P. Lim, 1994a: 330.—L.M. Chou, 1995: 146.—R. Subaraj et al., 1995: 5 (Taban Valley [BTNR]).—K. Lim, 1995: 20 (Cave Path [BTNR]).—R. Subaraj, 1996: 101.—R.C.H. Teo & Rajathurai, 1997: 399 (Fern Valley [BTNR]; Jungle Fall & Seraya Valleys [BTNR]; Nee Soon South [NSSF]; Taban & Lasia Valleys [BTNR]).—T.M. Leong & L.M. Chou, 1999: 110–113.

Rana doriae (non Boulenger, 1887)— Boulenger, 1912: 231.

Limnonectes plicatellus — Chan-ard et al., 1999: 17.—T.M. Leong, 2000: 7.—K.P. Lim & F.L.K. Lim 2002: 144.—K.K.P. Lim & T.M. Leong, 2008: 158, 264.—N. Baker & K.P. Lim, 2008: 59, 158.—P.K.L. Ng et al., 2011: 308.—T.M. Leong, 2011: 22.—N. Baker & K.P. Lim, 2012: 59, 158.—R.C.H. Teo & Thomas, 2019: 152, 179 (Bukit Timah Nature Reserve; Kampong Trail [RRNP]; Rifle Range Road Pipeline).

Limnonectes plicatella — Bickford et al., 2010: 121.

Remarks. The earliest record of L. plicatellus from Singapore is from Butler (1903) from a specimen he collected atop Bukit Timah Hill in June 1900. Subsequently, L. plicatellus went unrecorded from Singapore for 88 years (Table 2) until Lim (1988b) reported an individual that was seen at BTNR on 18 March 1988. However, examination of museum specimens shows that eight specimens were collected earlier between 1955 and 1974. Taylor (1962) cited Singapore as part of L. plicatellus distribution, likely referring to Butler’s record or the museum specimens. Two years after L. plicatellus was rediscovered, Lim (1990b) reported a new population at NSSF, and Teo & Thomas (2019) reported a population at RRNP, adjacent to BTNR.

Occurrence. Restricted, only known from a few localities within BTNR, NSSF, and RRNP. Locally common.

Singapore conservation status. Critically Endangered.

Conservation priority. Highest.

IUCN conservation status. Least Concern [2021].

LKCNHM & NHMUK Museum specimens. Singapore (no locality): BMNH 1902.3.26.7 (no date); Bukit Timah Nature Reserve: BMNH 1974.3584 (no date), ZRC.1.3388 (Sep-1996), ZRC.1.3386 (18-Oct-1996), ZRC.1.3383– ZRC.1.3385, ZRC.1.3387 (Aug-1996), ZRC.1.1535– ZRC.1.1539 (05-Aug-1974), ZRC.1.9181 (20-Jan-2002), ZRC.1.6210– ZRC.1.6216 (30-Dec-2000), ZRC.1.10512– ZRC.1.10515 (13- Mar-2003), ZRC.1.8132– ZRC.1.8140 (Jun-2001), ZRC.1.1516 (03-Oct-1987), ZRC.1.1517 (22- Nov-1986); Woodcutter’s Trail [NSSF]: ZRC.1.11326 (05-Mar-2004); Nee Soon Swamp Forest: ZRC.1.12576 (02-Feb-2007), ZRC.1.2928 (23-Nov-1990).

Additional Singapore museum specimens. Singapore (no locality): FMNH; Bukit Timah Hill [= BTNR]: BPBM, CAS.

Singapore localities. Bukit Timah Nature Reserve—Nee Soon Swamp Forest—Rifle Range Nature Park—Rifle Range Road Pipeline—Upper Seletar Reservoir Park.