New regional record and notes on historical specimens of Günther’s Toad Duttaphrynushololius with comments on other southeastern Indian congeners

 

Bhargavi Srinivasulu 1, S.R. Ganesh 2& Chelmala Srinivasulu3

 

1,3 Natural History Museum and Wildlife Biology and Taxonomy Lab, Department of Zoology, University College of Science, Osmania University, Hyderabad, Andhra Pradesh 500007, India

2 Chennai Snake Park, RajbhavanPost, Chennai, Tamil Nadu 600022, India

1 bharisrini@gmail.com, 2 snakeranglerr@gmail.com,3 hyd2masawa@gmail.com (corresponding author)

 

 

 

Abstract: We report on the finding of the Günther’s Toad Duttaphrynus hololius from Visakhapatnam and discuss aspects of its distribution based on our species distribution modeling.  We also provide data on historically collected specimens and refine its intra-specific variation, provide an up-to-date chresonymy and comment on the validity of earlier reported diagnosis.  Lastly, we remark on some misidentification-mediated dubious southern Indian records of another, related congener, the Marbled Toad D. stomaticusand correct some misallocations by referring them to another syntopic congener, the Dwarf Toad D. scaber.

 

Keywords: Chresonymy, distribution, Duttaphrynus stomaticus, D. scaber, D.hololius, misidentification, southern India, variation.

 

 

 

doi: http://dx.doi.org/10.11609/JoTT.o3621.4784-90   |  ZooBank:urn:lsid:zoobank.org:pub:71521A55-F94C-4DBE-9AB5-4803BA89C046

 

Editor: Sanjay Molur, ZOO/WILD, Coimbatore, India.       Date of publication: 26 September 2013 (online & print)

 

Manuscript details: Ms # o3621 | Received 09 May 2013 | Final received 12 September 2013 | Finally accepted 13 September 2013

 

Citation: Srinivasulu, B., S.R. Ganesh & C. Srinivasulu (2013).New regional record and notes on historical specimens of Günther’s Toad Duttaphrynus hololius with comments on other southeastern Indian congeners. Journal of Threatened Taxa 5(13): 4784–4790; http://dx.doi.org/10.11609/JoTT.o3621.4784-90

 

Copyright: © Srinivasulu et al. 2013. Creative Commons Attribution 3.0 UnportedLicense. JoTT allows unrestricted use of this article in any medium, reproduction and distribution by providing adequate credit to the authors and the source of publication.

 

Funding: Surveys in Eastern Ghats of Andhra Pradesh were supported by grants from Department of Biotechnology, Government of India and University Grants Commission, New Delhi.

 

Competing Interest: The authors declare no competing interests. Funding sources had no role in study design, data collection, results interpretation and manuscript writing.

 

Acknowledgements: We thank our respective organizations for supporting our research activities–BS and CS thank the Head, Department of Zoology, Osmania University, for facilities; DBT, New Delhi and UGC-DRS SAP III Department of Zoology, Osmania University for research grants; Shri A.V. Joseph IFS, Chief Conservator of Forests (Wildlife), Andhra Pradesh Forest Department and the Andhra Pradesh State Biodiversity Board for encouragement; Mr.G. Chethan Kumar for assistance in field survey. SRG is deeply grateful to Shri. B. Vijayaraghavan, Executive Chairman, Chennai Snake Park for the facilities provided; Dr. T.S. Sridhar (Madras Govt. Museum) and Dr. K. Venkataraman (Zoological Survey of India) for permitting examination of material under their care; Dr. Barry Clarke and Dr. Colin McCarthy (Natural History Museum, London) for providing the photographs of the holotype of D. hololiusand Mr. S.R. Chandramoulifor permitting the use of his photograph of Marbled Toad.

 

 

 

For images  -- click here

 

 

Recent studies on amphibians of southeasternIndia are scarce, contrary to that happening in the Western Ghats (Biju 2001; Gururaja 2012).  The available literature (Das 1991; Seshadri et al. 2012) is largely pertaining to community and behavioural ecology, save for a paper by Ganesh & Chandramouli(2011) that was on polymorphism and phenotypic plasticity.  Four species of toads, namely, Duttaphrynus melanostictus(Schneider, 1799), D. scaber (Schneider, 1799), D. cf. stomaticus (Lütken, 1862) (Figs. 2 & 3) and D. hololius (Günther, 1876) are known from eastern peninsular India (Dutta 1997; Daniels 2005 in part; Srinivasulu & Das 2008 in part; Chandramouli et al. 2011).  Duttaphrynus melanostictus is a widespread species that is relatively well known (Dutta 1997; Biju 2001).  The remaining species, D. scaber, D. cf. stomaticus and D. hololiusare still comparatively poorly known (Daniels 2005).

The Günther’s Toad Duttaphrynus hololius (Image 1) was originally described as Bufo hololius Günther, 1876 from “Malabar” which, as currently understood, is erroneous with regards to the type locality (see Biju et al. 2004). Subsequently, this species was sighted/studied, from drier, low-altitude places in eastern peninsular India, namely, Nellore in the Coramandelcoastal plains and Chittoor, Bangalore, Gingee, Thommaguddai, Kundu Reddiyur, Nagarjunasagar in the Eastern Ghats (Thurston 1888; Satyamurthi 1967; Pillai & Ravichandran 1991; Daniels 1992; Chandramouliet al. 2011; Adimallaiah et al. 2012; Kalaimani et al. 2012).  Due to paucity of data at that time and pending re-evaluation of specimens assigned to this species in its geographic range (sensu Dubois & Ohler1999), Srinivasulu & Das (2008), followed Dutta (1997) in considering the specimens from drier habitats of Eastern Ghats (Thurston 1888; Satyamurti1967; Pillai & Ravichandran1991) to be of doubtful identity needing clarifications.

However, recent studies on this species involving both wild-caught and museum materials (Ganesh & Asokan 2010; Chandramouli et al. 2011) have shed light on its identity, in-life colouration and distribution. Following these works, more sightings of D.hololius were reported from other places adjoining the Eastern Ghats (Adimallaiah et al. 2012;Kalaimani et al. 2012).  Only recently, has the larval characteristics of this species been documented (Ganesh et al. 2013).  In this paper, we present a new regional record for D. hololius and also discuss some unfortunate cases of published misidentifications of other southeasternIndian toads.

 

Material and Methods

This work is based on examination of fresh, wild-caught collections (BS, CS), examination of historical museum specimens and photographs of the holotype of D. hololius(SRG). Museum abbreviations are as follows: BMNH - Natural History Museum, London; FBS - Freshwater Biology Station, Hyderabad; MAD - Madras Govt. Museum, Chennai; ZSIM Zoological Survey of India, Madras (Chennai); NHM.OU - Natural History Museum of Osmania University, Hyderabad. Morphological examination of toads follows Dutta & Mananmendra-Arachchi(1996), and Dubois & Ohler (1999).

For the species distribution modeling we used the maximum entropy (MaxEnt) model as it is not affected by the limitation of the occurrence records and currently regarded as the most robust (Phillips et al. 2006). MaxEnt uses a maximum entropy approach to integrate model covariate selection and controls for overfitting by using smoothing and identifies how the covariates (i.e., spatial layers representing environmental variables or z) contribute to the model (Phillips et al. 2006; Elithet al. 2011).  We utilized 19 bioclimatic and one topographical variables obtained from the WorldClimdatabase (Hijmans et al. 2005) gridded to 30 arc-second (~1km) resolution for 1950–2000 time period with the following settings: Auto features (feature types are automatically selected depending on the training sample size), perform jackknife tests, logistic output format, random test percentage = 25, regularisation multiplier = 1, maximum iterations = 1000, convergence threshold = 0.0001 and maximum number of background points = 10,000.

 

Taxonomy

Duttaphrynus hololius (Günther, 1876)

Bufo hololius - Thurston 1888; Satyamurti 1967; Pillai & Ravichandran 1991

Bufo hololius - Dutta1997 in part; Dubois & Ohler 1999 in part; Srinivasulu & Das 2008 in part.

Duttaphrynus hololius - van Bocxlaer et al. 2009; Ganesh & Asokan 2010; Chandramouli et al. 2011; Adimallaiah et al. 2012; Kalaimaniet al. 2012.

Referred material (examined): NHM.OU.AMPHI/3.2012 coll. Bhargavi Srinivasulu from Scindia, Visakhapatnam, Andhra Pradesh; MAD unreg. coll. unknown, from Nellore, Andhra Pradesh; ZSIM (ex. FBS) A361 don. Dr. Mahator, fromNagarjunasagar, Andhra Pradesh.

Diagnosis: See Pillai & Ravichandran (1991), and Chandramouli et al. (2011) for colouration in life.

Description of NHM.OU.AMPHI/3.2012: A small-sized toad (18.52mm); head wider (6.72mm) than long (5.84mm); flat above; no cephalic ridges seen; canthus rostralissharp; nostrils circular and oriented laterally situated closer to the tip of the snout (1.01mm) than to the eye (1.31mm) with internarialdistance of 1.67mm; pupil horizontally oval; tympanum distinct about 28% of the eye diameter (3.21mm); parotid glands flattened; skin with numerous white dots and scattered scarlet swollen granules; fingers without webbing and toes webbed only at the base; two distinct palmar tubercles seen.

Colour in life: Dorsum dark brownish-grey; skin with numerous minute white dots and bulging scarlet glandules scattered throughout the dorsum; a very feeble vertebral line running from snout to vent; limbs with minute white dots dorsally and also show the presence of scattered bulging scarlet glandules; dorsal surface of both the fore and hind limbs slightly pale greyish to whitish in colour in comparison to the dorsum and with 2–4 black cross bars; venter largely pale grey and with numerous white granules throughout.

Measurements (in mm): Snout-vent length (SVL) 18.52, head width (HW) 6.72, head length (HL) 5.84, distance from back of mandible to nostril (MN) 5.52, distance from back of mandible to front of eye (MFE) 3.21, distance from back of mandible to back of eye (MBE) 1.39, distance between front of eyes (IFE) 3.13, distance between back of eyes (IBE) 6.07, internarialspace (IN) 1.67, distance from nostril to tip of the snout (NS) 1.01, distance from front of eye to nostril (EN) 1.31, eye length (EL) 3.21, tympanum diameter (TYD) 0.91, tympanum to eye distance (TYE) 0.48, minimum distance between upper eyelids (IUE) 2.82, maximum width of upper eyelid (UEW) 5.02, distance from anterior corner of eye to tip of snout (SL) 2.41, forelimb length (from elbow to base of outer palmar tubercle) (FLL) 5.98, hand length (from base of outer palmar tubercle to tip of third finger) (HAL) 4.84, length of third finger from basal border or proximal subarticular tubercle (TFL) 3.82, tibia length (TL) 7.23, Maximum tibia width (TW) 1.36, femur length (from vent to knee) (FL) 7.39, length of tarsus and foot (from base of tarsus of tip of fourth toe) (TFOL) 11.54, foot length (from base of outer palmar tubercle to tip of third finger) (FOL) 7.06, length of fourth toe from basal border of proximal subarticular tubercle (FTL) 4.26, length of inner metatarsal tubercle (IMT) 0.80, inner toe length (ITL) 0.81, distance from distal edge of metatarsal tubercle to maximum incurvationof web between fourth and fifth toe (MTTF) 3.66, distance from distal edge of metatarsal tubercle to maximum incurvation of web between third and fourth toe (MTFF) 4.21, distance from maximum incurvation of web between third and fourth toe to tip of fourth toe (TFTF) 2.33, and distance from maximum incurvationof web between fourth and fifth toe to tip of fourth toe (FFTF) 3.49.

Locality and natural history: The toad was collected at 12.30hr, in February 2012, from under the prop roots of a large banyan tree abutting a tropical dry deciduous hillock near Scindia (17.68N, 83.29E; 1.2m), ca. 200m from the sea shore in Visakhapatnam (Image 2), Andhra Pradesh State, India. This record is the northeasternmost locality and closest to the sea coast.

Furthermore, we provide additional data from historically collected specimens that we studied to establish conspecificity.  Additional data on morphometryfrom the two voucher specimens is as follows (in mm): snout vent length 37.40–39.35; head length 10.48–10.51; head width 13.72–14.26; head depth 5.44–6.19; interorbital distance 7.95–9.55; internarial distance 3.05–4.42; upper eyelid width 3.60–3.75; eye diameter (horizontal) 3.80–5.80; tympanum diameter (horizontal) 3.15–4.40; upper arm length 6.75–8.10; lower arm length 8.50–10.35; palmar length 7.80–8.55; relative finger lengths 3>4>1>2; femoral length 12.90–13.90; tibio-tarsal length 12.90–14.35; metatarsal length 15.50–18.65; relative toe lengths 4>3>5>2>1.  Some observed differences between our present measurements and that reported earlier for the same specimens are attributable to preservation artifact.

 

Discussion

Tympanum and eye relative sizes were considered to be taxonomically meaningful (Daniel 1963) and hence of diagnostic importance. Immature specimens, like in most other animals, have larger eyes with respect to tympanum.  In adults, the eye diameter is slightly lesser than the tympanum diameter.  Although our data from these old museum specimens is impacted by preservation process, our conclusions on conspecificity and allometricvariations are strongly supported by the measurements of live, uncollected D.hololius gleaned from recently published literature (Chandramouli et al. 2011).

Since Biju et al. (2004), Duttaphrynus hololius has been reported from four locations in southern Eastern Ghats [Devarabetta, Hosur District (Chandramouli et al. 2011), Thommaguddai and Kundu Reddiyur, Vellore District and Gingee,Villupuram District in Tamil Nadu (Kalaimani et al. 2012)] and central Eastern Ghats [Nagarjunasagar, NalgondaDistrict, Andhra Pradesh (Adimallaiah et al. 2012)] (Image 3).  The species distribution model shows that the species might have a broader distribution extent covering the southern parts of peninsular India and the Deccan Plateau, including those of southern Maharashtra bordering Karnataka; most of Karnataka; Tamil Nadu (where the likelihood of species occurrence is high); northern parts of Kerala and all along the Eastern Ghats, the eastern coast of Andhra Pradesh and Tamil Nadu and southern parts of Andhra Pradesh, contrary to what is documented (Image 3).  More dedicated surveys would yield a better understanding of its range.

Status of other southeast Indian toads: Unfortunately, there had been some issues on the identification of other sympatric congeners as well. The Marbled Toad D. stomaticus (Image 4), a predominantly northern Indian species (Dutta1997 in part; Daniels 2005 in part; Khan 2006) had been incorrectly reported from southern India in recent times (e.g., Gururaja2012; Hegde 2012; Seshadriet al. 2012).  Daniels (2005) in his treatment of peninsular Indian amphibians,specifically mentions the distribution of D. stomaticusto be from “Karnataka, Maharashtra, Orissa, Bihar and West Bengal.” As Daniels (2005) lists Bufo stomaticus peninsularis Rao, 1920 in the synonymy of D. stomaticus, he had to include its type locality Karnataka in the distribution too. This over-circumscribed concept of ‘D. stomaticus’ following the ‘conservative approach’ (as explained in Chandramouliet al. 2011) with “conspecifics” sensu lato originating from outside the known distribution of D.stomaticus sensu stricto (e.g., southwesternKarnataka—after Rao 1920; southern Tamil Nadu—after Dutta 1997; Sondhi2009) had probably resulted in such incorrect records. Our critical examination of captioned-photographs of southern Indian ‘D. stomaticus’ in such publications revealed that these were cases of misidentification of D.scaber (Schneider, 1799), which seem more widely distributed in western region of peninsular India (Padhyeet al. 2013).  We, herein, remove D. ‘stomaticus’ sensu Gururaja (2012), Hegde (2012) andSeshadri et al. (2012) from the chresonymyof D. stomaticus sensu stricto and based on crown structure, densely warted and depressed body (see Dubois & Ohler 1999 for more details) refer them to that of D. scaber (Image 5), a species belonging to a different species-group (after Dubois & Ohler 1999) when compared with D. stomaticus and D. hololius (see Dubois & Ohler1999; Boxclaer et al. 2009 read with Chandramouli et al. 2011).

 

 

References

 

Adimallaiah, D., V.V. Rao & G. Surender(2012). Report of Günther’s Toad Duttaphrynus hololius (Günther, 1876) from Nalgonda District, Andhra Pradesh. Cobra 6(2): 8–11.

Biju, S.D. (2001). A synopsis to the frog fauna of Western Ghats, India. Occasional Publication, Indian Society for Conservation Biology, 1–24 pp.

Biju, S.D., S.K. Dutta, K. Vasudevan, S.P. Vijaykumar, C. Srinivasulu & G.D. Bhuddhe(2004). Duttaphrynus hololius. In: IUCN 2010. IUCN Red List of Threatened Species. Version 2010.4. www.iucnredlist.org. Downloaded on 16 April 2013.

Chandramouli, S.R., S.R. Ganesh & N. Baskaran (2011). On recent sightings of a little known toad, Duttaphrynus hololius (Günther, 1876) with notes on its morphological characterization and ecology. Herpetology Notes 4: 271–274.

Daniel, J.C. (1963). Field guide to the amphibians of western India. Part 1 and 2. Journal of the Bombay Natural History Society 60: 415–438, 690–702.

Daniels, R.J.R. (1992). Range extension in some south Indian amphibians. Hamadryad 17: 40–42.

Daniels, R.J.R. (2005). Amphibians of Peninsular India. Universities Press (India) Private Limited, Hyderabad, India, 141–160 pp.

Das, I. (1991). Trophic ecology of a community of south Indian anuran amphibians. DPhil Thesis, University of Oxford, UK.

Dubois, A. & A. Ohler (1999). Asian and oriental toads of the Bufo melanostictus, Bufo scaber and Bufo stejnegeri groups (Amphibia,Anura): a list of available names and redescription of some name-bearing types. Journal of South Asian Natural History 4(2): 133–180.

Dutta, S.K. & K. Manamendra-Arachchi(1996). The Amphibian Fauna of Sri Lanka. Colombo, Sri Lanka, Wildlife Heritage Trust of Sri Lanka, 232pp.

Dutta, S.K. (1997). Amphibians of India and Sri Lanka (Checklist and Bibliography). Bhubaneswar, India, Odyssey Publishing House, India, xiii+342pp+xxii.

Elith, J., S.J. Phillips, T. Hastie, M. Dudík, Y.E.Chee & C.J. Yates (2011). A statistical explanation of MaxEntfor ecologists. Diversity and Distributions 17: 43–57; http://dx.doi.org/10.1111/j.1472-4642.2010.00725.x

Ganesh, S.R. & J.R. Asokan (2010). Catalogue of Indian herpetological specimens in the collection of the Government museum, Chennai, India. Hamadryad35(1): 46–63.

Ganesh, S.R. & S.R. Chandramouli (2011). Report of some noteworthy specimens and species of Herpetofauna from South-east India. Taprobanica 3(1): 5–10; http://dx.doi.org/10.4038/tapro.v3i1.3227

Ganesh, S.R., A. Kalaimani, A. Nath & R.B. Kumar (2013). First observations on the larval characteristics of Günther’sToad Duttaphrynus hololius (Günther 1986). Herpetotropicos  9(1–2): 5–8.

Gururaja, K.V. (2012). Pictorial Guide to the Frogs and Toads of the Western Ghats. Gubbi Labs Publications, Bangalore, India, 154+xviiipp.

Hegde, V.D. (2012). Amphibian fauna of arecanut plantation inKadatoka (Uttara Kannada) Western Ghats, Karnataka. Frog Leg 18: 10–20.

Hijmans, R.J., S.E. Cameron, J.L. Parra, P.G. Jones & A. Jarvis (2005). Very high resolution interpolated climate surfaces for global land areas. International Journal of Climatology 25: 1965–1978; http://dx.doi.org/10.1002/joc.1276 

Kalaimani, A., A. Nath & R.B. Kumar (2012). A note on the records of rare and endemic Duttaphrynus hololius (Günther, 1876). Frog Leg 18: 27–30.

Khan, M.S. (2006). Amphibians and Reptiles of Pakistan. KreigerPublishing Company, Malabar, Florida, USA, 311pp.

Padhye, A., R. Pandit, R. Patil, S. Gaikwad, N. Dahanukar& Y. Shouche (2013).Range extension of Ferguson’s Toad Duttaphrynus scaber (Schneider) (Amphibia:Anura: Bufonidae) up to the northern most limit of Western Ghats, with its advertisement call analysis. Journal of Threatened Taxa 5(11): 4579–4585; http://dx.doi.org/10.11609/JoTT.o3345.4579-85

Phillips, S.J., R.P. Anderson & R.E. Schapire(2006). Maximum Entropy modeling of species geographic distribution. EcologicalModeling 190: 231–259; http://dx.doi.org/10.1016/j.ecolmodel.2005.03.026

Pillai, R.S. & M.S. Ravichandran(1991). On a rare toad Bufo hololius Günther from Nagarjunasagar, Andhra Pradesh. Records of the Zoological Survey of India 88(1): 11–14.

Rao, C.R.N. (1920). Some South Indian Batrachians. Journal of the Bombay Natural History Society 27: 119–127.

Satyamurthi, S.T. (1967). The South Indian Amphibiain the collection of the Madras Government Museum. Bulletin of the Madras Government Museum new series Natural History Section 7(2): 1–90; p 1. I-XIII.

Seshadri, K.S., C. Vivek & K.V. Gururaja (2012). Anurans from wetlands of Puducherry, along the East Coast of India. Check List 8(1): 23–26.

Sondhi, S. (2009). Herpetofauna of Tuticorin. Publication of Forest Research Institute, Dehradun, India.

Srinivasulu, C. & I. Das (2008). The herpetofauna of Nallamalahills, Eastern Ghats India: an annotated checklist, with remarks on nomenclature, taxonomy, habitat use, adaptive types and biogeography. Asiatic Herpetological Research 11: 110–131.

Thurston, E. (1888). Catalogue of Batrachia, Salientia and Apoda (Frogs, toads and caecilians) of southern India. The superintendent, Government Press, Madras, 52pp+pl.13.

van Bocxlaer, I., S.D. Biju, S.P. Loader & F. Bossuyt (2009). Toad radiation reveals into-India dispersal as a source of endemism in the Western Ghats-Sri Lanka biodiversity hotspot. BMC Evolutionary Biology 9: 131; http://dx.doi.org/10.1186/1471-2148-9-131