Description

Beduka koynayensis is a small toad with a snout-vent length range of 26.5 - 31.8 mm (Biju et al. 2009); females have a larger average body size of 30.84 +/- 1.12 mm than males, who have an average of 29.83 +/- 1.34 mm (Gaitonde et al. 2016). There are no cranial crests on the head. The snout is short, rounded, and concave in the ventral view. The lips are smooth and stick out. The nostrils are lateral, swollen, and twice as close to the tip of the snout than to the eyes. The canthus rostralis is distinguished by a straight ridge formed by a single row of rounded tubercles, which extend around to the anterior border of the eye. The loreal region slopes very strongly. The width of the interorbital region is subequal to the upper eyelid. The upper eyelid has tubercles on a thickened rim. The tympanic annulus is not distinct, and is one-fifth the diameter of the eye. The tympanic area is very tuberculate, covering the entire tympanum. The parotid glands are not clearly visible but are sub triangular in shape; the posterior ends of the parotid glands are narrower than the anterior ones. The fingers are free and non-dilated. The second finger is shorter than the first. The subarticular tubercles are single and somewhat developed on the fingers. The tarsometatarsal articulation reaches the tympanum. There is no tarsal ridge. There are two metatarsal tubercles, with the inner one being larger and more apparent. The toes do not have any fringe and have a minimal amount of webbing at their base. The subarticular tubercles are single and somewhat visible. The dorsal skin is randomly scattered with rounded, low tubercles of varying sizes separated by smooth skin. The limb tubercles are close together in space having a distinct cone-shaped appearance and tendency towards being spine-like. The ventral surfaces of the body are granular (Grandison and Daniel 1964).

Beduka koynayensis is a rather small species when compared to other “Bufo'' with a mature body length of less than 34 mm. Beduka koynayensis is visually similar to Bufo brevirostris, but these two can be distinguished by B. koynayensis having the following characteristics: a smaller tympanum, concave head, and differing integument. Bufo brevirostris is covered with small uniform tubercles with a small row of larger warts on the median line of the back, differing from the random scattered pattern of B. koynayensis. Additionally, B. brevirostris has spiny tubercles on the throat and abdomen, while B. koynayensis does not have the same spinosity of the venter (Grandison and Daniel 1964).

As of 2021, only two species are in the genus Beduka: B. tigeria and B. koynayensis. Beduka tigeria differs from B. koynayensis by the former having a slightly larger body size, an elongated body, discontinuous canthal and preorbital ridges, stripes on the lateral and dorsal side, and a more yellow body. Beduka koynayensis’s body is scattered with random, rounded, small melanin-tipped warts on the smooth dorsum, while B. tigeria has a denser arrangement of granular projections with horny spinules on the dorsal and lateral parts of the head, back, and flank. Beduka tigeria has a more prominent canthal and preorbital ridge, as well as a snout that is longer than eye length. The parotids in B. koynayensis are indistinct and sub triangular, while being distinct and rounded in B. tigeria. The lack of webbing between the finger and toes in B. tigerina also differentiate it from B. koyayensis. Beduka tigeria has a longer shank than thigh, and a foot length that is longer than the shank and thigh when compared to B. koynayensis. The yellow color of B. koynayensis is duller than B. tigeria and has distinct striping patterns (Grandison and Daniel 1964, Biju et al. 2009). Beduka tigeria and B. koynayensis have similar advertisement calls with a similar peak frequency and structure of pulses. However, the temperature at which the calls were recorded slightly differed; B. tigeria mating calls were recorded at 24°C, while B. koynayensis was at 19°C (Biju et al. 2009).

In life, B. koynayensis bodies are dark brown with yellow patches on the thighs, shoulders, and flanks. The dorsal tubercles are melanin-tipped. In preservative, the dorsal surfaces are a uniform dark brown with the subtle tint of a dull chrome-yellow. The flanks, sides of the thighs, and area above the arm insertions have bright chrome-yellow patches. The surfaces of the lips and ventral sides are cream colored. The throat and abdomen sometimes contain small, random irregularly shaped dark brown spots on the surface of them. The tubercles found underneath the limbs near the vent and on the infra-tympanic area were white in some specimens (Grandison and Daniel 1964).

Compared to other paratypes of B. koynayensis, the holotype has webbing that is more reduced than others. The other specimens have 2½ phalanges free from the web on the external area of the 3rd toe and 3½ - 3¾ free on both sides on the 4th toe (Grandison and Daniel 1964).

Beduka koynayensis lack distinct sexual dimorphism. However, females are generally larger than males (Gaitonde et al. 2016) and male B. koynayensis vary greatly in their degree of sexual development and maturity. All male B. koynayensis have nuptial asperities that contain pockets of dark brown spinules. In the most sexually developed males, these dark brown spinules extend to the latero-dorsal surface of the 1st and 2nd fingers and the lateral side of the 3rd finger. These same spinules are also present on the inner palmar tubercle. Additionally, B. koynayenesis contain a median singular vocal sac that communicates via their mouth. In three specimens, the posterior part of the sac had a broad, heavily pigmented, transverse band (Grandison and Daniel 1964).

Distribution and Habitat

Country distribution from AmphibiaWeb's database: India

View distribution map in BerkeleyMapper.

The holotype and other specimens were collected approximately 4000 ft from Humbelevi Village in the Koyna Satara District of Maharashtra, India (Grandison and Daniel 1964). The species is only known from two localities at Koyna and Aboli (Biju et al. 2004). Beduka koynayensis inhabit wet evergreen forests and dry riparian grasslands with natural laterite rocky habitat that allow unique and fragile ecosystems of diverse flora and fauna to be sustained. Beduka koynayensis is endemic and restricted to a narrow altitudinal range of 700 - 1000 m above sea level (Biju et al. 2004, Gaitonde et al. 2016).

Life History, Abundance, Activity, and Special Behaviors

Beduka as a genus has a particularly explosive mating system, specifically during the rainy monsoons seasons, which occur from the months of June to September. They breed on the ground in disturbed patches of evergreen forests. Male B. koynayensis will cluster near boulders and start a chorus to attract potential females. Advertisement calls have a peak frequency of 2569 - 3016 Hz at temperatures around 19 °C (Gaitonde et al. 2016).

There is an intense competition for females between male B. koynayensis because there is a ratio of 7 males to every 1 female (Gaitonde et al. 2016).

During reproduction, male B. koynayensis were found using two to three pelvic thrusts when trying to amplect a female (Gaitonde et al. 2016).

The average clutch size for B. koynayensis was 960 eggs for 6 pairs of species. The diameter of the eggs with and without the jelly coat for B. koynayensis is 2.60 +/- 0.3 mm and 1.72 +/- 0.26 mm respectively. The ratio of egg to jelly is 1.51 mm (Gaitonde et al. 2016).

Mosquito larvae, aquatic beetles, but no other anurans inhabited the same environment as the tadpoles of B. koynayensis. Terrestrial crabs and water scorpions are predators of B. koynayensis tadpoles (Gaitonde et al. 2016).

Trends and Threats

Beduka koynayensis has a severely restricted distribution. The breeding sites of B. koynayensis are legally protected as their distribution falls under the Sahyadri Tiger Reserve. Despite these protections, road mortality and the removal of their habitat for construction projects may be a threat to the species (Gaitonde et al. 2016).

Possible reasons for amphibian decline

General habitat alteration and loss
Habitat modification from deforestation, or logging related activities
Disturbance or death from vehicular traffic
Predators (natural or introduced)
Disease
Climate change, increased UVB or increased sensitivity to it, etc.

Comments

An investigation of the family, Bufonidae, in 2009 using Bayesian Inference, Maximum Likelihood, and Maximum Parsimony on NCX1 and CXCR4 nuclear DNA and 12SrRNA, tRNAVAL, 16SrRNA, tRNALEU, ND1, tRNAILE, tRNAGLN, tRNAMET, ND2 mtDNA found that B. koynayensis and B. tigeria were sister species and were significantly different enough from other members of the family as to warrant the elevation to their own genus (Bocxlaer et al. 2009). This genus was coined Xanthrophryne by Biju et al. (2009) but later changed to Beduka (Dubois et al. 2021). These analyses also showed the Beduka genus is closely related to the genus Duttaphrynus, with “Bufo'' and Duttaphrynus sharing the most recent common ancestor of Bufo melanostictus (Biju et al. 2009).

The genus “Beduka” means "toad" in the Marathi language in Maharashtra, India (Dubois et al. 2021).

The “koynay” part of the species epithet, “koynayensis”, is most likely derived from the locality of Koyna in Maharashtra, India in which B. koynayensis is found (Gaitonde et al. 2016).

The original genus name, "Xanthophyrne" is derived from the Greek word “xanthos” meaning "yellow" and “phryne” meaning "toad" (Biju et al. 2009). The genus name Xanthophyrne (Biju et al. 2009) was considered to be nomenclaturally unavailable and thus Beduka was proposed as a replacement (Dubois et al. 2021).

What is the relevance of this to the account? i.e. this feels more about the Leptodactylus species than BedukaLeptodactylus pentadactylus and its sister species Leptodactylus knudseni have the same mating call; similar to the relationship between B. tigerina and koynayensis (Heyer et. al 2003, Gaitonde et al. 2016).

References

Biju, S.D., Dutta, S., Inger, R. (2004). "Xanthophryne koynayensis." The IUCN Red List of Threatened Species 2004: e.T54684A11173845. https://dx.doi.org/10.2305/IUCN.UK.2004.RLTS.T54684A11173845.en. Downloaded on 09 June 2021.

Biju, SD, Bocxlaer, IV, Giri, VV, Loader, SP., Bosssuyt, F (2009). "Two new endemic genera and a new species of toad (Anura: Bufonidae) from the Western Ghats of India." BMC Evolutionary Biology, 2, 241-247. [link]

Bocxlaer, Ines Van, Biju, SD, Loader, Simon P., Bosssuyt, Franky (2009). "Toad radiation reveals into-India dispersal as a source of endemism in the Western Ghats–Sri Lanka biodiversity hotspot." BMC Evolutionary Biology, 9, 131-141.

Gaitonde N., Giri, V., Kunte, K. (2016). "‘On the rocks’: Reproductive biology of the endemic toad Xanthophyrne (Anura: Bufonidae) from the Western Ghats, India." Journal of Natural History, 50(39-40), 2557-2572. [link]

Grandison, A.G.C., Daniel, J.C. (1964) “Description of a new species of toad (Anura: Bufonidae) from Satara district, Maharashtra, India.” The journal of the Bombay Natural History Society 61(1): 192-194.

Heyer W, De Sa RO, Rettig A (2003). "Sibling species, advertisement calls, and reproductive isolation in frogs of the Leptodactylus pentadactylus species cluster (Amphibia, Leptodactylidae)." Herpetol Petropolitana, [link]

Species Account Citation: AmphibiaWeb 2021 Beduka koynayensis: Humbali Village Toad <https://amphibiaweb.org/species/216> University of California, Berkeley, CA, USA. Accessed Nov 24, 2024.

Citation: AmphibiaWeb. 2024. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 24 Nov 2024.

AmphibiaWeb's policy on data use.