Xenopeltis unicolor H. Boie

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 : 231-238

Xenopeltis unicolor H. Boie in F. Boie, 1827— Native.

Xenopeltis unicolor H. Boie in F. Boie, 1827: 564. Syntype (1): RMNH.RENA.24, by original designation. Type locality: “ Java ”, Indonesia .

Iridescent Earth Snake

( Figure 26F ; Lower Peirce Forest)

Singapore records.

Xenopeltis unicolor — Cantor, 1847b: 902.— Cantor, 1847c: 1069, 1076.—Peters, 1859: 269 (Princess Hill [= BG]).— Ģnther, 1864: 181.— Dennys, 1880a: 3.— Dennys, 1880b: 2.— Dennys, 1881b: 2.— Blanford, 1881: 215.— Hoffmann, 1890b: 1627.—Sclater, 1891a: 10.— Boulenger, 1893: 168.— Flower, 1896: 878 (Princess Hill [= BG]; Tanglin [= TF]; Tanjong Katong).— Hanitsch, 1898: 19.— Flower, 1899: 657.—Ridley, 1899: 207.— Hanitsch, 1912b: 15.—J.C. Thompson, 1913: 415.—J.C. Thompson, 1914: 380.— de Rooij, 1917: 39.—Sworder, 1923: 60.— Buddle, 1929: 37 (Sembawang Naval Base [= SML]).— de Haas, 1950: 528.— Harman, 1961: 182.— Leviton, 1983: 198, 199.—F.L.K. Lim, 1984: 17.—K. Lim & F. Lim, 1988c: 75 (Lim Chu Kang).— Ngim et al., 1988: 91 (Alexandra Park [= AW]).—K. Lim, 1989h: 63 (Sime Road Forest).— F.L.K. Lim & M.T.-M. Lee, 1989: 116.—K. Lim, 1990a: 6 (Lim Chu Kang Road [LCK]; Sungei Buloh [SBWR]).—K.K.P. Lim & L.M. Chou, 1990: 53.—F.L.K. Lim, 1991: 52.—K.K.P. Lim & Subharaj, 1992: 5 (Canberra Road; Central Library-Kent Ridge [NUS]; Kranji Dam; Lim Chu Kang Road [LCK]; Nee Soon Swamp Forest; Old Upper Thomson Road; Rifle Range Road; Ulu Seletar Road-Upper Thomson Road).—K.K.P. Lim & F.L.K. Lim, 1992: 50, 145.—Wee, 1992: 74 (Lower Peirce Reservoir Park).—K.K.P. Lim, 1993b: 1 (Choa Chu Kang Road [CCK]; Lim Chu Kang Road [LCK]).—K.K.P. Lim & Subaraj, 1994: 5 (King Albert Park).—K.K.P. Lim & Subaraj, 1994: 5 (Neo Tiew Road [LCK]; Rifle Range Road).—R. Subaraj, 1994: 12 (MacRitchie North Forest).—L.M. Chou et al., 1994: 106.—R. Subaraj et al., 1995: 2 (King Albert Park).—K. Lim et al., 1995: 13 (Island Club Road [SICC]; Upper Peirce Reservoir Park).—K. Lim, 1995: 14 (Upper Peirce Park Service Road [UPRR]).— David & Vogel, 1996: 39.— Manthey & Grossmann, 1997: 436.—R.C.H. Teo & Rajathurai, 1997: 378.—Chan-ard et al., 1999: 39.—Orlov et al., 2000: 70.— Iskandar & Colijn, 2001: 32.—K.P. Lim & F.L.K. Lim, 2002: 145.— Anonymous, 2003: 92 (Sungei Buloh Wetland Reserve).— de Lang & Vogel, 2005: 238.—N. Baker & K.P. Lim, 2008: 92, 160.—E.K. Chua, 2010: 101.— Das, 2010: 353.—P.K.L. Ng et al., 2011: 298.— Das, 2012a: 140.—Waeschenbach, 2013: 495.—H.H. Tan, 2014c: 118 (Nee Soon Swamp Forest).—Wallach et al., 2014: 802.—Chan-ard et al., 2015: 152.—R. Subaraj, 2015: 54 (Ulu Sembawang Forest).—S. Subaraj, 2015: 6 (Night Safari).—K.K.P. Lim et al., 2016: 179 (Pulau Tekong).— de Lang, 2017: 368.— Das, 2018: 23.—H.C. Ho et al., 2019: 124 (Clementi Forest).—K.K.P. Lim et al., 2019: 295.—H.T.W. Tan et al., 2019: 134 (Kent Ridge Park; National University of Singapore Kent Ridge Campus).—Van Nguyen et al., 2019: 39.— Charlton, 2020: 72.— Cross, 2020b: 1 (Changi; Sime Road Camp [= SICC]).— Cross, 2020c: 1 (Sime Road Camp [= SICC]).— Cross, 2020d: 1 (Sime Road Camp [= SICC]).— Cross, 2020e: 1, 2 (Changi; Sime Road Camp [= SICC]).— Cross, 2020f: 1 (Sime Road Camp [= SICC]).— Cross, 2020g: 1 (Sime Road Camp [= SICC]).— Cross, 2020h: 7.— Cross, 2020i: 1, 2, 3 (Sime Road Camp [= SICC]).— Cross, 2020k: 1 (Sime Road Camp [= SICC]).— Cross, 2020l: 1 (Sime Road Camp [= SICC]).— Cross, 2020m: 1, 5 (Bukit Timah Golf Course [= SICC]; Sime Road Camp [= SICC]).— Cross, 2020n: 1, 7 (Changi; Sime Road Camp [= SICC]).—K.K.P. Lim, 2020: 4 (Bukit Timah Golf Course [= SICC]; Changi; Sime Road Camp [= SICC]).—Rookmaaker, 2021: 168.— Figueroa et al., 2022: 1.—Orlov et al., 2022: 237.

Remarks. Due to its fossorial lifestyle, X. unicolor is considered uncommon (Sworder 1923; Baker & Lim 2012); however, several specimens were collected early on. Cantor (1847b) was the first to report X. unicolor from Singapore from a specimen collected by Montgomerie. Peters (1859) examined a specimen collected at Princess Hill (BG), Blanford (1881) reported it from the Raffles Museum, Sclater (1891) examined one specimen collected by Gardner and four from Spon; Boulenger (1893) noted a specimen from Dennys at NHMUK, Flower (1896) collected two at Tanjong Katong and Tanglin, and Thompson (1913) indicated one at CAS. Buddle (1929) provided an account of X. unicolor in his list of snakes from SNB and mentioned it was rare, but did not specify the number of specimens observed. After that, X. unicolor was reported 32 years later ( Table 2 ) by Harman (1961) who found it to be one of the more common snakes, a view shared by Teo & Rajathurai (1997). Cross (2020n) also recorded several specimens between 1944 and 1945 while detained as a POW at Sime Road Internment Camp. Although many records were published in The Pangolin journal, only one record was published in Singapore Biodiversity Records. That record consisted of a juvenile X. unicolor photographed at NSSF on 2 April 2014 (Tan 2014c). Other recent records include sightings at USF (R. Subaraj 2015), Night Safari (S. Subaraj 2015), PT ( Lim et al. 2016), CF (Ho et al. 2019), and KRP and NUS Kent Ridge Campus (Tan et al. 2019). The individual in Figure 26F was photographed at LPF on 30 November 2014 (A. Figueroa pers. obs.).

Occurrence. Wide-ranging. Uncommon.

Singapore conservation status. Least Concern.

Conservation priority. Moderate.

IUCN conservation status. Least Concern [2012].

LKCNHM & NHMUK Museum specimens. Singapore (no locality) : BMNH 1880.9 .10.24 (no date), ZRC.2.3076 (06-Nov-1924) , ZRC.2.3080 (1986), ZRC.2.3081 (Apr-1989); Botanic Gardens : ZRC. 2.3079 (no date); Bukit Kalang [ SRF] : ZRC.2.6923 (17-Sep-2010); Changi : ZRC.2.3078 (Feb-1928); Folkestone Road : ZRC.2.7069 (03-Jun-2014); Holland Road : ZRC. 2.6303 (27-Nov-2006); Island Club Road [ SICC] : ZRC.2.6494 (24-May-2007) , ZRC.2.6809 (16-Mar-2009); Jalan Kampong Chantek : ZRC. 2.5705 (18- Apr-2003); Kent Ridge Campus [ NUS] : ZRC.2.3369 (Jun-1992) , ZRC.2.7338 (26-Nov-2018); Kent Ridge Park : ZRC.2.6821 (25-May-2009); Lim Chu Kang : ZRC.2.2400 (Nov-1988); Nee Soon Swamp Forest : ZRC.2.7058 (02-Apr-2014); Old Upper Thomson Road : ZRC.2.6715 (21-Jul-2008); Owen Road : ZRC.2.3077 (1915); Rifle Range Road : ZRC.2.5532 (21-Apr-2002); Stamford Road : ZRC.2.3075 (Jan-1907); Sungei Buloh Wetland Reserve : ZRC.2.2607 (18-Jun-1990) ; University of Singapore Bukit Timah Campus [ NUS]: ZRC.2.7112 (Mar-1970) ; Upper Thomson Road : ZRC.2.6820 (06-May-2009) ; Yishun Avenue 1: ZRC.2.6087 (17-Aug-2004) .

Additional Singapore museum specimens. Singapore (no locality): CAS, SAMA; Princess Hill [= BG]: ZMB; Sungei Buloh Wetland Reserve: UWBM; University of Malay [= NUS]: BPBM, MCZ.

Singapore localities. Alexandra Woodlands—Bukit Gombak—Canberra Road—Changi—Choa Chu Kang— Clementi Forest—Folkestone Road—Holland Road—Jalan Kampong Chantek—Jalan Ulu Seletar—Kent Ridge Park—King Albert Park—Kranji Dam—Lim Chu Kang—Lower Peirce Forest—Lower Peirce Reservoir Park—MacRitchie North Forest—National University of Singapore Bukit Timah Campus— National University of Singapore Kent Ridge Campus—Nee Soon Swamp Forest—Night Safari—Old Upper Thomson Road—Owen Road—Pulau Tekong—Rifle Range Road—Sembcorp Marine Ltd.—Sime Road Forest—Singapore Botanic Gardens—Singapore Island Country Club—Stamford Road—Sungei Buloh Wetland Reserve—Tyersall Forest—Tanjong Katong—Ulu Sembawang Forest—Upper Peirce Reservoir Park—Upper Peirce Reservoir Road—Upper Thomson Road—Yishun Avenue 1.

Excluded Species (143 species)

Our primary motive for updating Singapore’s herpetofauna checklist was to explicitly remove species from the checklist for whose non-occurrence in Singapore we have credible support for. Over the years, some species have been expunged, yet others continue to be listed, either as indeterminate or doubtful, but without explanation. To help avoid future misunderstandings, for each species account we provide a rationale for omitting it from Singapore’s checklist. Other species are connected to Singapore because they have either entered Singapore as stowaways or were intentionally released by the public, but have not established wild populations. We include these species here to explain their occurrence in Singapore and ensure they are not added in future checklists.

Here, we identify and exclude 143 species from Singapore’s herpetofauna ( Table 3). For clarity, we divide this section into three parts: 1) Uncertain species; 2) Non-established introduced species, and; 3) Erroneous species. The erroneous species section is further subdivided into three parts: 3a) Mislabelled or confused species; 3b) Species listed without basis, and; 3c) Speculated species.

The species tally for each section is as follows: 1) Uncertain species = 5 species; 2) Non-established introduced species = 40 species; 3) Erroneous species = 97 species, consisting of; 3a) Mislabelled or confused species = 71 species; 3b) Species listed without basis = 21 species, and; 3) Speculated species = 8 species.

1) Uncertain species (5 species)

We recognise the five snake species below as “uncertain” because we are unable to form a strong conclusion as to whether the individuals reported originated in Singapore ( Table 3). Thus, we await to see if more individuals for each of these species are found.

Class Reptilia Laurenti, 1768 (5 species)

Order Squamata Oppel, 1811 (5 species)

Figures

FIGURE 26. A) Trimeresurus hageni, B)Trimeresurus purpureomaculatus, C)Tropidolaemus wagleri (male), D) Tropidolaemus wagleri (juvenile female), E) Tropidolaemus wagleri (adult female), F) Xenopeltis unicolor, G) Hydrophis cyanocinctus, and H) Hydrophis viperinus. Photographs by: Alex Figueroa [A–F], and Sanjaya Bandara [G–H].

Tables

TABLE 3. Checklist of the 143 herpetofauna species excluded from the checklist of Singapore’s herpetofauna. The presence of each of the following species has not been confirmed in Singapore or the species has been introduced, but has not established viable populations. The list of excluded species comprises 13 frogs and 129 reptiles (three crocodilians, 21 turtles, 37 lizards, and 69 snakes).

Taxon	Status in Singapore
AMPHIBIA (13)
Bufonidae (3) Ingerophrynus celebensis
Ingerophrynus parvus Phrynoidis asper Dicroglossidae (2)	Erroneous Erroneous
Limnonectes doriae Limnonectes kuhlii Pelodryadidae (1)	Erroneous Erroneous
Ranoidea caerulea	Non-native; Introduced

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