SEAVR 2020: 014‐017
ISSN: 2424‐8525
Date of publication: 20 April 2020
Hosted online by ecologyasia.com

Notes on reproductive ecology of Kalophrynus sinensis (Peters, 1867)
on Mindanao Island, Philippines
Erl Pfian T. MAGLANGIT, Sharmaine Ann A. BONACHITA, Mark Joseph T. ARNADO & Olga M. NUÑEZA
erlpfianmaglangit@gmail.com (Maglangit)

Observers: Sharmaine Ann A. Bonachita, Joseph T. Arnado, Maxelle Campaña, Elbert B. Caballero, Donna Jeane Sy
Esmero, Erl Pfian T. Maglangit.
Photographs by: Erl Pfian T. Maglangit.
Subjects identified by: Erl Pfian T. Maglangit, Arvin C. Diesmos.
Location: Mambuntan Falls, Barangay Lubilan, Municipality of Naawan, Misamis Oriental Province, Mindanao
Island, Philippines. 08°24’46.536” N, 124°21’5.02” E.
Elevation: 440 metres ASL.
Habitat: Temporary pool in mixed secondary growth habitat.
Date and time: 17 March 2019, 19:30 hrs.
Identity of subject:
Rufous‐sided Sticky Frog (or ‘Philippine Sticky Frog’), Kalophrynus sinensis (Amphibia: Anura: Microhylidae)
Description of records:
During herpetological fieldwork in Mambuntan Falls on 14‐18 March 2019, the breeding habit of Rufous‐sided
Sticky Frog Kalophrynus sinensis was observed. Four adult male K. sinensis individuals in a shallow temporary pool
(1.7m length x 1.2m width) within a mixed secondary forest were observed simultaneously vocalizing in a loudsynchronized chorus after heavy rainfall in the afternoon, and exhibited parental care by guarding egg masses (Figs
1 and 2). The area was humid (RH=78%), and the habitat comprised regrown dipterocarps, bamboos, shrubs andunderstorey vegetation (Fig. 4). There was a flowing stream 2.5m away from the temporary pool.

Fig. 1 Male K. sinensis guarding egg masses© Erl Pfian T. Maglangit

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Clutch size ranged from 90‐98 eggs (mean clutch size=94; n=5) and these were enclosed in a cylindrical film‐likestructure. Upon closer examination, the eggs were already in Stage 8 and Stage 12 of development (Gosner, 1960).
Differentiated blastomeres and light hemispheres were already visible and slightly pronounced. Subsequently, apair of partially submerged K. sinensis in inguinal amplexus, adjacent to the four‐male K. sinensis group, was alsoobserved (Fig. 3).

Fig. 2 Male K. sinensis guarding egg masses© Erl Pfian T. Maglangit

Fig. 3 A pair of K. sinensis in amplexus in a shallow pool

© Erl Pfian T. Maglangit

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Fig. 4 Mixed secondary forest habitat© Erl Pfian T. Maglangit

Remarks:
Kalophrynus sinensis, previously identified as K. pleurostigma, is native to the Philippines (Diesmos et al, 2015). Itis a medium‐sized microhylid with (i) distinct dark mark on the back, (ii) dorsal skin forms thick glandular cover frombehind the eyes to vent, (iii) dorsal surface lightly rugose to granular rugose, (iv) no spiny tubercles aside frompigmented dome‐like tubercles common on posterior third of trunk, (v) coarsely granular body on dorsal andventral section, (vi) body widest on sacral region, (vii) well‐developed subarticular tubercles, (viii) absence ofvomerine teeth, (ix) lack of webbing on fingers with slightly swollen and rounded tips, and (x) presence of nuptial
pads which are distinct in males (Inger, 1954; Zug, 2015).
In the Philippines, it is known to occur on the islands of Basilan, Bohol, Camiguin Sur, Culion, Dinagat, Leyte,
Mindanao and Samar (Diesmos et al. 2015; Venturina et al. 2020) and it usually hides under leaf litter during theday and forages on the forest floor at night (Zug, 2015). It breeds in small, shallow pools and is frequently
encountered during the rainy season while calling and floating in temporary pools (Zug, 2015; Sanguila et al. 2016).
The reproductive ecology and parental care of the genus Kalophrynus is not well‐documented. Available
information is mostly on species‐habitat occurrences and advertisement calls (Orlov and Ananjeva 2007; Matsui etal. 2012). Breeding behavior of some species documented (e.g. K. cryptophonus and K. yongi) were phytothelm
breeders, which use specific ecological niche (e.g. bamboo stems, bromeliads, pitchers, etc.) for the survival of theiroffspring (Vassilieva et al., 2014; Zug, 2015).
Microhylid frogs often use small or temporary ponds for breeding (Zug, 2015). Frogs that breed in small water
bodies either produce fewer eggs or disperse their clutch to several small aquatic sites and/or exhibit parental carefor their eggs and/or tadpoles (Duellman and Trueb, 1985; Krügel and Richter, 1995). Small eggs and large clutch
sizes are typical of species ovipositing in water, whereas large eggs and small clutch size are typical of those
ovipositing out of water (Alcala, 1962). The K. sinensis population in Naawan, Mindanao Island utilized a temporary
pool and deposited large clutches of eggs and exhibited unique parental care. Parental association with theirdeveloping offspring is relatively uncommon yet advantageous for the survival of offspring.
Our observation provides new information on parental care strategy, breeding preference, multiple egg clutch
placement and egg clutch size for K. sinensis.

16Note:
Photographic vouchers were deposited in the Lee Kong Chian Natural History Museum, National University ofSingapore (NUS) (ZRC [IMG] 1.185‐1.186).
Acknowledgements:
We thank the Philippine Department of Environmental and Natural Resources Region X for providing a researchpermit, the local government unit of Naawan, Misamis Oriental, Mambuntan Falls management foraccommodation and to Kelvin Lim (Lee Kong Chian Natural History Museum of the National University of Singapore)for technical assistance in cataloguing photographic vouchers. We are also grateful to Emerson Y. Sy, Antonio N.
Lorenzo II, and Russell Evan L. Venturina for their comments and suggestions on an earlier draft of this note.
References:Alcala, A. C. (1962). Breeding behavior and early development of frogs of Negros, Philippine Islands. Copeia 1962(4):679‐726.
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