Description
Duttaphrynus hololius is a small to medium-sized toad with a snout-vent length of 40 - 50 mm, with females generally being larger than males. The head is wider than long and flat when viewed from above. No cephalic ridges are seen. The canthus rostralis is sharp. The nostrils are circular, oriented laterally, and situated closer to snout tip than to eye. The snout is rounded and loreal region concave. The pupil is horizontally oval. The tympanum is distinct, almost bordering postcircumorbital and subequal (3/4^th) to eye diameter, in adults. The habitus is depressed. The digital formula for the manus is 3 > 4 > 1 > 2 and for the pes is 4 > 3 > 5 > 2 >1. The fingers are free, and the toes are 1/4^th webbed with webbing in 4th toe in level with the antepenultimate and not exceeding the penultimate subarticular tubercle. The palmar tubercles are prominent with the outer one being larger. The inner metatarsal tubercle larger than outer and the plantar tubercles are similar to supernumerary tubercles. The parotid glands are flattened extending downwards up to antehumeral region. The skin has numerous white dots and scattered scarlet swollen granules (Gunther 1876, Thurston 1888, Satyamurthy 1967, Chandramouli et al. 2011, Bhargavi et al. 2013).

Duttaphrynus hololius is a species of Duttaphrynus inhabiting peninsular India, belonging to D. stomaticus (Lütken 1862) species-group characterized by a seemingly smooth and wet dorsal skin, devoid of strong warts; but has rounded glandular patches; crown without cephalic ridges; canthus rostralis evident; snout square and blunt; webbing very meagre (< 25%) in toes, none in fingers (Gunther 1876, Thurston 1888, Satyamurthy 1967, Chandramouli et al. 2011 Bhargavi et al. 2013).

In the field, this species only resembles D. stomaticus (Lütken, 1862), which also completely lacks “cephalic ridges” sensu Dubois & Ohler (1999), but can be distinguished as follows: skin with glandular patches in D. hololius (vs. skin with pointed tubercles in D. stomaticus); absence of spiny warts or tubercles on head and limbs (vs. presence); webbing in toes 1/4^th (vs. 2/3^rd); inner metatarsal tubercle larger than the outer (vs. equal); habitus depressed (vs. plump and rounded), see Chandramouli et al. (2011). Apart from this, the only other toads that are sympatric with D. hololius are D. melanostictus (Schneider, 1799) and D. scaber (Schneider, 1799) that belong to entirely different species-groups both morphologically (Dubois and Ohler 1999) and genetically (Van Bocxlaer et al. 2009).

In life, the dorsum is dark brownish-grey and skin has numerous minute white dots and bulging scarlet glandules scattered throughout the dorsum. There is a very feeble vertebral line running from snout to vent. The limbs have minute white dots dorsally and also show the presence of scattered bulging scarlet glandules. The dorsal surface of both the fore- and hind-limbs are slightly pale greyish to whitish in colour in comparison to the dorsum and with 2 – 4 black cross bars. The venter is largely pale grey and has numerous white granules throughout (Chandramouli et al. 2011, Bhargavi et al. 2013).

Ontogenetic color variation has been documented. The red-colored dots on glandular patches that are bright and contrasting in young ones will fade out become indistinct in old adults (Chandramouli et al. 2011, Ganesh et al. 2013).

Distribution and Habitat

Country distribution from AmphibiaWeb's database: India

View distribution map in BerkeleyMapper.

Duttaphrynus hololius is found in peninsular India at elevations of 300 - 1300 m asl in the Deccan plateau and the Eastern Ghats where it inhabits open rocky outcrops with sparse vegetation (Satyamurthy 1967, Pillai and Ravichandran 1991, Ganesh and Asokan 2010, Chandramouli et al. 2011, Kalaimani et al. 2012, Bhargavi et al. 2013).

Life History, Abundance, Activity, and Special Behaviors
Duttaphrynus hololius is one of the few rock-dwelling toads in peninsular India. It is the only range-restricted amphibian occurring in the dry zone of this region endemic to Deccan plateau and Eastern Ghats. It is nocturnal, at least as adult. At night, adult toads have been sighted on the move, on cool sheet-rocks, whereas by daytime, they were found resting underneath rocks (Chandramouli et al. 2011, Bhargavi et al. 2013).

Duttaphrynus hololius breeds between July and December (post-monsoon season) in seasonal rainwater pools, most often those formed on rocky substratum (contrary to pools on soil surface). The tadpoles are gregarious (about 30 - 50 in number, per pool) and feed on benthic substances in such pools. Tadpoles feed even during daytime where (water and air) temperatures are unusually high for amphibians, i.e., >35^oC (Ganesh et al. 2013, Chandramouli and Kalaiamani 2014).

Trends and Threats
Since this species is completely partial to rock formation, stone quarrying, blasting, mining activities, and any depletion in extent and quality of rock formation are directly wiping out wild populations of this species. Also, depleting water resources in such rocky outcrops inhibits its breeding, due to shortage or complete lack of rainwater pools for breeding and spawning (Chandramouli et al. 2011, Bhargavi et al. 2013, Ganesh et al. 2013, Chandramouli and Kalaimani 2014).

Possible reasons for amphibian decline

Habitat modification from deforestation, or logging related activities
Prolonged drought
Mining

Comments
The species authority is: Günther, A. C. L. G. 1876 "1875". Third report on collections of Indian reptiles obtained by the British Museum. Proceedings of the Zoological Society of London 1875: 567–577.

Duttaphrynus hololius is allied to Duttaphrynus stomaticus (Lütken, 1862) group (see Dubois and Ohler, 1999; Van Boxclaer et al., 2009 read with Chandramouli et al., 2011). Dubois and Ohler (1999), after their morphological analysis of Asian and Oriental bufonids, stated that D. hololius should provisionally be regarded as a member of D. stomaticus species-group, pending its revision. But Van Bocxlaer et al. (2009), after their molecular revision (maximum parsimony- and maximum likelihood criteria, in Bayesian framework) including both nuclear and mitochondrial genes using sampled taxa (n=86 spp.) from other genera, stated that D. hololius belongs to “Remaining Indian Subcontinent” clade consisting of D. dhufarensis in addition to D. hololius and D. stomaticus.

The type locality mentioned in the original description “Malabar”, a part of Western Ghats mountains, is actually incorrect (Biju 2001, contra Srinivasulu and Das 2008) and is indeed out of the known distribution of this species, as currently understood (Bhargavi et al. 2013).

Until Chandramouli et al. (2011), this species was very poorly known (Dutta 1997, Dubois and Ohler 1999, Radhakrishnan and Ravichandran 1999).

References

Bhargavi.S, Ganesh, S.R., Srinivasulu, C. (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.

Biju, S. D. (2001). ''A synopsis of the frog fauna of the Western Ghats, India.'' Indian Society for Conservation Biology, 1, 1-24.

Chandramouli, S.R., Ganesh, S.R., Baskaran, N. (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.

Chandramouli, S.R., Kalaimani, A. (2014). ''Description of the larvae of Günther’s toad Duttaphrynus hololius (Günther, 1876) (Anura: Bufonidae) with notes on development and oral ultra-structure.'' Alytes, 31(2), 3-12.

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

Dutta, S. K. (1997). Amphibians of India and Sri Lanka (Checklist and Bibliography). Odyssey Publishing House, Bhubaneswar, Orissa, India.

Ganesh, S. R., Kalaimani, A., Nath, A, Kumar, R. B. (2013). ''First observations on the larval characteristics of Günther's Toad Duttaphrynus hololius (Günther, 1876).'' Herpetotropicos, 9, 5–8.

Ganesh, S.R., Asokan, J.R. (2010). ''Catalogue of Indian herpetological specimens in the collection of the Government museum, Chennai, India.'' Hamadryad, 35(1), 46–63.

Günther, A. (1876). ''Third report on collection of Indian reptiles obtained by British Museum.'' Proceedings of the Zoological Society of London, 567-577.

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

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

Satyamurthi, S.T. (1967). ''The South Indian Amphibia in the collection of the Madras Government Museum.'' Bulletin of the Madras Government Museum new series Natural History Section, 7(2), 1-90.

Srinivasulu, C., Das, I. (2008). ''The herpetofauna of Nallamala hills, 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.

Species Account Citation: AmphibiaWeb 2017 Duttaphrynus hololius: Guenther's Toad <https://amphibiaweb.org/species/196> University of California, Berkeley, CA, USA. Accessed Dec 23, 2024.

Citation: AmphibiaWeb. 2024. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 23 Dec 2024.

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