Frogs of Borneo.

Description
Staurois latopalmatus is the largest foot-flagging frog species, with males reaching 40 - 50 mm in snout-vent length and females reaching 60 - 75 mm. The description is based on Inger et al. (2017) and the first description by Boulenger (1887): A mid-sized frog that is neither slender nor sturdy with a very short, broadly rounded snout, which slopes backwards from the tip to the mouth. It has large eyes, with vertically oval pupils. The tympanum is very small and indistinct. The fingers are short, with massive disks, equalling ¾ of the width of the eye. The hands have a broad webbing, extending nearly to the disks, between the two outer fingers, and a shorter one between the second and third fingers. The legs are long and very muscular, with the femoral-tibial articulation reaches the shoulder. The tibia length equals the distance between tympanum and vent. The feet have very broadly webbed toes, with the web enclosing half of the disks. The toe discs are about half the size of finger disks. The subarticular tubercles are oval and flat, and there is no distinct metatarsal tubercle. Dorsal skin is granulated while the ventral skin is smooth. Around the dorso-lateral edge of the body, tubercles are elongated along the anterior- posterior axis.

The species is very unique-looking and can be easily distinguished from all sympatric species, including other Staurois species by the pug-like snout (Boulenger 1887, Inger et al. 2017).

Life coloration consists of a dark brown to black dorsal color, with small, bright mottles, which in some specimens form a web-like pattern on the back; hind limbs with lighter cross bands; ventral surface white. The upper 2/3 of the iris is often orange to red, the lower part beige to silver (Boulenger 1887, Inger et al. 2017).

Intensity and density of the dorsal pattern varies tremendously, and can also be more yellow than white. Furthermore, several photos published online also show individuals with a brighter ground coloration, tending towards light olive-green (Boulenger 1887, Inger et al. 2017).

Distribution and Habitat

Country distribution from AmphibiaWeb's database: Indonesia, Malaysia

Malaysian region distribution from AmphibiaWeb's database: Sabah, Sarawak

View distribution map in BerkeleyMapper.

The species is distributed in northern and western Borneo and thus occurring in Malaysia (Sabah and Sarawak), Indonesia and Brunei (Frost 2023). It dwells on medium to large, rocky streams below 1000 m asl, where the species prefers areas with strong currents and often can be found clinging to vertical rock surfaces.

Staurois latopalmatus mainly occurs in primary forests but can also be found in disturbed areas, as long as some tree cover still exists along the stream banks (Inger et al. 2017).

Life History, Abundance, Activity, and Special Behaviors
Staurois latopalmatus appears to be active during day and night with peaks of activity in the morning and the late afternoon (Boeckle et al. 2009). It is mostly found perching on rocks and boulders in the water or very close (<2m) to the water line. In contrast to other Staurois ssp. the acoustic repertoire of the males consists of two different call types, a short chirp (one note, dominant frequency of 5165Hz) and a longer trill (up to 44 notes, dominant frequency of 4942Hz), latter sometimes shows some modulation (Boeckle et al. 2009). Mentioned authors report calling activity in the day as well as the night time, “Frogs of Borneo” (Haas et al. 2024) state that the species calls at night.

Like in other Staurois species, males perform foot-flagging for visual communication (Preininger et al. 2009).

The food of S. latopalmatus consists of aquatic insect larvae, which they probably pick up from submerged rock surfaces (Inger et al. 2017).

Larva
In contrast to other Bornean Staurois the larva of this species is still unknown to science (Haas et al. 2022).

Trends and Threats
The species needs fast flowing, clear streams in relatively healthy forests (Inger et al. 2017). Therefore it is not only threatened by ongoing deforestation but also by anthropogenic siltation of rivers and creeks. However, IUCN (2018) lists the species as “Least Concern”.

Possible reasons for amphibian decline

General habitat alteration and loss
Habitat modification from deforestation, or logging related activities
Drainage of habitat
Dams changing river flow and/or covering habitat
Subtle changes to necessary specialized habitat
Habitat fragmentation

Comments
Matsui and Seto (1985) described the karyotype of Staurois latopalmatus to be of the ancestral ranid type, which consists of 26 chromosomes in 5 large and 8 small pairs.

References
Boeckle, M., Preininger, D., and Hödl, W. (2009). Communication in noisy environments I: acoustic signals of Staurois latopalmatus Boulenger 1887. Herpetologica, 65(2), 154-165. [link]

Boulenger, G. A. (1887). On new reptiles and batrachians from North Borneo. Annals and Magazine of Natural History, 20(5), 95–97 [link]

Frost, D. R. (2023). Amphibian Species of the World: an Online Reference. Version 6.2 (20.11.2023). Electronic Database accessible at https://amphibiansoftheworld.amnh.org/index.php. American Museum of Natural History, New York, USA.

Haas, A., Das, I., Hertwig, S. T., Bublies, P., and Schulz-Schaeffer, R. (2022). A Guide to the Tadpoles of Borneo. tredition.

Haas, A., Das, I., and Hertwig, S. T. (2024). Frogs of Borneo – The frogs of East Malaysia and their larval forms. Electronic Database accessible at http://www.frogsofborneo.org. Visited online on 02.03.24.

Inger, R. F., Stuebing, R. B., Grafe, U., and Dehling, J. M. (2017). A Field Guide to the Frogs of Borneo. Natural History Publications (Borneo) Limited, Kota Kinabalu.

IUCN SSC Amphibian Specialist Group. (2018). Staurois latopalmatus. The IUCN Red List of Threatened Species 2018: e.T58761A114924500. https://dx.doi.org/10.2305/IUCN.UK.2018-1.RLTS.T58761A114924500.en. Accessed on 04 March 2024.

Matsui, M., and Seto, T. (1985). Karyotype of an Asian ranid frog, Staurois latopalmatus. Japanese Journal of Herpetology, 11, 1-4. [link]

Preininger, D., Boeckle, M., and Hödl, W. (2009). Communication in noisy environments II: visual signaling behavior of male foot-flagging frogs Staurois latopalmatus. Herpetologica, 65(2), 166-173. [link]

Species Account Citation: AmphibiaWeb 2024 Staurois latopalmatus: Sabah Splash Frog <https://amphibiaweb.org/species/5190> University of California, Berkeley, CA, USA. Accessed Apr 17, 2024.

Citation: AmphibiaWeb. 2024. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 17 Apr 2024.

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