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On the Occurrence of Malayopython Reticulatus (Schneider, 1801) in Mainland India (Squamata: Pythonidae)

On the Occurrence of Malayopython Reticulatus (Schneider, 1801) in Mainland India (Squamata: Pythonidae)

Herpetology Notes, volume 11: 703-708 (2018) (published online on 26 August 2018)

On the Occurrence of reticulatus (Schneider, 1801) in Mainland (: )

Yatindra Kalki1,*, Tristan D. Schramer1, and Daniel B. Wylie1

Abstract. We investigated six historical Malayopython reticulatus museum specimens thought to have been collected from mainland India and examined their validity. Most specimens offered insufficient data to support collection from present-day mainland India and were discounted. Despite this, one specimen (UIMNH 62394) collected in “Calcutta, India” prior to 1965 cannot be so easily dismissed and may represent the first legitimate M. reticulatus specimen from continental India. We address the likelihood of this finding and discuss its implications regarding the occurrence of M. reticulatus on the Indian mainland.

Keywords. collections, dispersal, distribution, mainland India, Malayopython reticulatus, museum records, museum specimen, reticulated , West Bengal

Introduction the country (�������������������������������� Daniel, 2002; Whitaker and Captain, 2004). In 2012, The , Malayopython reticulatus a single adult female was captured and documented in (Schneider, 1801), is a large-bodied constrictor found Baidyabati Hooghly, West Bengal, India (Mukherjee et across South and Southeast including , al., 2012) just north of Kolkata. This observation was , , , Lao PDR, , thought to be the first and only legitimate record of M. , , Brunei Darussalam, , reticulatus from mainland India. East , and the (Deuve, 1970; Auliya et al., 2002, 2006; Das, 2007; O’Shea and Lazell, Materials and Methods 2008; Das, 2010; O’Shea et al., 2015; Barker et al. 2018). Currently, the only accepted populations of M. We searched the online museum collection databases reticulatus within the political boundaries of India occur VertNet (2018), iDigBio (2018), and AQUiLA (2018) on the (Rajeshkumar et al., 2015), for Malayopython reticulatus and known synonyms which lie across the Bay of Bengal to the southeast using ‘India’ as the country field input. Additionally, we of the Indian subcontinent near the northern tip of searched the University of Illinois Museum of Natural . However, populations exist in adjacent eastern History database and contacted the Bombay Museum of Bangladesh within the Chittagong and Sylhet Hills Natural History for additional specimens. A total of six (Kock and Schröder, 1981; Nishat et al., 2002; Auliya, historical museum specimens of M. reticulatus thought 2006). Despite the proximity of these populations, the to have been collected from the mainland of the Indian presence of the on mainland India remains subcontinent were discovered. Of the six specimens, uncertain and there is little consensus among scientific one is from the University of Illinois Museum of Natural authorities regarding its historic occurrence within History (UIMNH), two are from the American Museum of Natural History (AMNH), one is from the Museum of Comparative Zoology (MCZ) at Harvard University, and two are from the Zoological Museum University of Copenhagen (ZMUC). Once specimen data were

1 Illinois Natural History Survey, Prairie Research Institute, acquired, their provenance and localities were analysed 1816 South Oak St., Champaign, Illinois 61820, USA. for validity and either dismissed or investigated further. * Corresponding author. E-mail: [email protected] 704 Yatindra Kalki et al. Table 1. Summary of collection data available for six specimens of Malayopython reticulatus purportedly from mainland India. Table 1. Summary of collection data available for six specimens of Malayopython reticulatus purportedly from mainland India.

Catalogue Institution Verbatim Interpretation Year Collector Number Location

R-4213 MCZ Asia: India Indian Empire; included Bangladesh and parts of Myanmar. 1832 Edward Gerard, Jr. The fact that Edward Gerard was a wildlife importer and (assistant to John exporter as well as a taxidermist for the British Museum Edward Gray) calls the validity of the record into question

R-5462 ZMUC East India Vague; possibly referring to East Indies () Pre-1870 Matthiesen

R-5469 ZMUC East India Vague; possibly referring to East Indies (Southeast Asia) Pre-1870 Matthiesen

R-3019 AMNH India Vague Pre-1916 P.D. Scott

R-158209 AMNH India Vague 1969 No Data

62394 UIMNH Calcutta, India Kolkata, India Pre-1965 No Data

Results python. While both of these species are present in the Kolkata region (Daniel, 2002), they are also present Table 1 summarizes the data associated with the six in other parts of South and Southeast Asia where the investigated M. reticulatus specimens and provides an presence of M. reticulatus has been confirmed. interpretation of the verbatim collection locality. The data for most specimens offered only vague and out- Discussion dated locality information and could, therefore, be dismissed. However, one specimen (UIMNH 62394) Given the available information, the occurrence of M. possessed sufficiently specific locality data to warrant reticulatus on the Indian mainland is indeed plausible further investigation. Snout-vent length (SVL) and tail length (TL) of the specimen were measured to the nearest mm using a non-elastic string we ran along the midline of the body from the snout to the cloacal plate and further to the tail tip. The string was then placed on a measuring tape to obtain the final length measurements. Adding SVL and TL yielded total length (TTL). We also recorded the midbody dorsal, ventral, and subcaudal scale counts. The ventral scale count did not include the cloacal scale and the subcaudal scale count included the tail tip. UIMNH 62394 is listed as having been collected in “Calcutta, India” [now Kolkata, India] by an unknown collector on an unknown date; the collection must predate 1965, which was the year it was accessioned into the UIMNH collection. Upon examination, the specimen was found to be a juvenile female M. reticulatus with 1513 mm SVL + 235 mm TL = 1748 mm TTL, possessing 64 midbody dorsal scale rows, 310 ventrals, and 92 subcaudals (Figs. 1, 2). The stomach was dissected to obtain additional evidence from dietary data but yielded no contents. Further exploration revealed that a Tokay gecko (Gekko gecko; UIMNH 62395), and Figure 1. Lateral (top) and dorsal (bottom) views of the head an Oriental (Ptyas mucosa; UIMNH 62393) of Malayopython reticulatus (UIMNH 62394), purportedly were also collected in “Calcutta, India” along with the from mainland India. On the Occurrence of Malayopython reticulatus in Mainland India 705

for this circumstance. Based on the current evidence and our deductions, we postulate several options concerning the possible occurrence of M. reticulatus in West Bengal and mainland India as a whole.

Option 1: Low population density and insufficient sampling.—This option implies that a population of these does indeed exist in eastern West Bengal, but the number of individuals is small enough that it has largely avoided detection. The climate and vegetation of eastern West Bengal closely resemble those in regions known to support M. reticulatus populations, such as the Chittagong Hill Tracts and Sylhet Hills of Bangladesh (Table 2). Nishat et al. (2002) described the habitat of those bio-ecological regions as tropical semi-evergreen forest and considered the two regions continuations of each other extending through the Indian State of Tripura. The M. reticulatus specimens reported from these regions have largely been found in old- growth forest in association with both lotic and lentic water bodies (Ahsan, 2015). Much of the northeast hills region of India, particularly Tripura, superficially resembles and is contiguous with Bangladeshi habitat. The habitat of eastern West Bengal transitions from mangroves in the south to freshwater swamp forest and lowland tropical moist deciduous forest to the north and west (Champion and Seth, 1968; Olson et al., 2001) with numerous riparian connections that could allow M. reticulatus to exist. Being less than 2.5 meters in (SVL), UIMNH 63294 should be considered a juvenile (Shine et al., 1999) and may be evidence of a breeding population in eastern West Bengal. If populations of M. reticulatus do indeed exist in northeastern India, one would expect there to be more Figure 2. Ventral (top) and dorsal (bottom) views of UIMNH records from that region as M. reticulatus commonly 62394, a specimen of Malayopython reticulatus, purportedly flourishes in -altered habitat by feeding on human- from mainland India. commensal (Devan-Song et al., 2017). However, this human-commensal nature of M. reticulatus may only hold true for populations in regions with high M. reticulatus abundance. At the edge of their ranges, species and cannot be dismissed. The two records with the tend to have lower abundances and lower population most specific location data, UIMNH 63294 and the live densities (Bridle and Vines, 2007) and, if it is indeed specimen documented by Mukherjee et al. (2012), were present, northeastern India would be at the northwestern both from eastern West Bengal in the Kolkata area. The extent of the range of M. reticulatus. Additionally, locations of these records are from within Baidyabati northeastern India is home to approximately 145 tribal Hooghly and Kolkata—cities which lie approximately communities that practice extensive traditional hunting 25 km apart along the Hooghly River. The presence of of wildlife (Hilaluddin and Ghose, 2005; Aiyadurai, multiple M. reticulatus specimens in this region, which 2011). These long-term pressures may have reduced is nearly 400 km west of the nearest well-documented already scarce M. reticulatus populations and forced population in eastern Bangladesh (Khan, 1982), raises them into more remote areas. Furthermore, northeastern many questions regarding the mechanism responsible India is largely under-surveyed in terms of herpetofauna 706 Yatindra Kalki et al.

Table 2. Climate and habitat comparisons between known Bangladesh locations and suspected India locations for Malayopython reticulatusTable 2. Climate. Abbreviations and habitat of the comparisons Köppen betweenClimate known Classifications Bangladesh include locations ����������������������������������������������� and suspected India locations for Malayopython reticulatus. Abbreviations of the Köppen Climate Classifications include monsoon climate (Am), tropical savannah climate (Aw), (Aw),humid humid subtropical subtropical climate climate (Cwa), and(Cwa), humid and subtropical humid subtropical climate / subtropical climate / subtropical oceanic highland oceanic climate highland (Cwb). climate Numbered (Cwb). references Numbered are referenceslisted below are the listed table. below the table

Region Köppen Climate Habitat Malayopython reticulatus References Classifications Presence

Chittagong Hill Tracts Am, Aw Tropical semi-evergreen forest Confirmed 1–3 (Bangladesh)

Sylhet Hills (Bangladesh) Am, Cwa Tropical semi-evergreen forest Confirmed 1–3

West Bengal (India) Aw, Cwa Freshwater swamp forest, mangrove swamp, tropical Uncertain 2, 4–6 moist deciduous forest

Tripura (India) Aw, Cwa Tropical moist deciduous forest Likely 2, 4–6

Mizoram (India) Am, Aw Rainforest, tropical moist deciduous forest, tropical wet Likely 2, 4–6 evergreen forest

Manipur (India) Am, Aw Rainforest, tropical moist deciduous forest, tropical wet Uncertain 2, 4–6 evergreen forest

Meghalaya (India) Am, Cwa, Cwb Subtropical forest, tropical moist deciduous forest Uncertain 2, 4–6

Assam (India) Cwa, Am Semi-evergreen forest, tropical moist deciduous forest Uncertain 2, 4–6

Odisha (India) Aw, Cwa Mangrove swamp, tropical moist deciduous forest, Uncertain 2, 4–6 tropical semi-evergreen forest

(1) Nishat et al. (2002); (2) Peel et al. (2007); (3) Ahsan (2015); (4) Champion & Seth (1968); (5) Olson et al. (2001); (6) Vattakaven et al. (2016).

compared to other regions of India (e.g., Pawar et al., anthropic factors like hunting and habitat loss (Whitaker 2007). The recent discoveries of a number of new and Whitaker, 1980). Consequently, M. reticulatus species and range extensions for and in populations in the area may have gone undocumented the region attest to this deficiency and demonstrate the due to insufficient survey efforts coupled with low M. need for more robust survey efforts (Chatterjee, 2008). reticulatus population density. As a result, extensive and targeted surveys in the future could have the potential to discover new populations Option 2: Long-distance dispersal, deliberate or of M. reticulatus in the states of Tripura, , accidental.—An alternative hypothesis is that there Manipur, Mizoram, and Assam. is no breeding population of M. reticulatus currently The Asian water monitor (Varanus salvator) shares present in West Bengal but that some individuals many ecological attributes with M. reticulatus, namely periodically traverse the long distance to India from being semi-aquatic and associated with waterways regions to the east and southeast. The exceptional (Thornton, 1997), but also sharing comparable dispersal abilities of M. reticulatus have been proven by distributions and climatic tolerances with one another their recolonization of Krakatau Island after a volcanic (Mark Auliya, pers. comm.). The distribution of eruption (Thornton, 1996; Murray-Dickson et al., V. salvator on mainland India is restricted to the 2017). Regions known to harbour M. reticulatus are northeastern regions of the country: Assam (Islam connected to West Bengal and northeastern Indian states and Saikia, 2013); Tripura (Majumder et al., 2012); via the Ganges and Brahmaputra River basins (Mirza Mizoram (Lalremsanga et al., 2010); Meghalaya (Das, et al., 1998). Malayopython reticulatus is known to be 1988); West Bengal (Whitaker and Whitaker, 1980); a proficient swimmer (Murray-Dickson et al., 2017) and Orissa (Pandav, 1993). Breeding populations of and prefers riparian habitat (Smith, 1943), thus river- V. salvator exist in the mangroves of the Sundarbans mediated dispersal of a few M. reticulatus individuals of West Bengal (Whitaker and Whitaker, 1980), so into continental India is possible. Alternatively, M. it may be possible that undetected populations of reticulatus individuals could have been washed out to M. reticulatus occur there as well. Furthermore, the sea from the western coast of Myanmar or the panhandle wildlife in the region has historically been pressured by of Bangladesh during a cyclone. These snakes could On the Occurrence of Malayopython reticulatus in Mainland India 707 then have swum to the mangroves of the Sundarbans References with the aid of surface currents (Michida and Yoritaka, Ahsan, M.F. (2015): Malayopython reticulatus. In: IUCN 1996; Auliya et al., 2002) and travelled north into the Bangladesh. Red List of Bangladesh. Volume 4. and Kolkata region of West Bengal. Amphibians. IUCN, International Union for Conservation of Nature, Bangladesh Country Office, Dhaka, Bangladesh. Option 3: Human-mediated dispersal.—Another Aiyadurai, A. 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Accepted by Hinrich Kaiser

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