Description
Boophis obscurus is a robust frog with a snout-vent length between 42.4 - 81.9 mm in males (only one female was collected). The head of Boophis obscurus is longer than it is wide, and the head is slightly wider than the body. The snout is long and rounded in the dorsal and lateral view. Also, the nostrils are directly lateral, nearer to the eye than the snout. The canthus rostralis is sharp and straight when seen dorsally. The rostralis almost reaches the tip of the snout. The tympanum is large and distinct while the supratympanic fold is thick and also distinct. The vomerine odontophores can be viewed and are well separated in two patches. The tongue is posteriorly bifid and free. The body in comparison is moderately robust. The limbs are also moderately robust and there are single round subarticular tubercles. The inner palmar tubercle is not distinct and is in close contact with the nuptial pad which is creamy yellow in coloration. The fingers on the limbs are webbed with dermal fringes. The relative length of the forelimbed fingers are 1 < 2 < 4 < 3. Finger 2 especially is shorter than finger 4. The hindlimbed fingers are 1 > 2 > 3 = 5 < 4 in length. At the ends of all the toes, finger discs are also enlarged. The skin texture on the dorsal are smooth but covered with small warts. It can be seen that the posterior third of the back has more of these small warts that have keratinized black spicules. The ventral skin is granular (Glaw et al. 2010).

As a Boophis, this genus has an intercalary element between the ultimate and penultimate phalanges in the fingers and toes, nuptial pads, absence of femoral and gular glands in males, enlarged terminal discs at the fingers and toes, lateral webbing on the metatarsalia, absence of outer metatarsal tubercle, and overall similarity to other Boophis species. It is then assigned to the group Boophis goudoti based on moderate to large sizing, brownish dorsal color, non-transparent ventral skin, single subgular vocal sac, vomerine teeth, webbing between fingers, sharp canthus rostralis, and molecular phylogenetic relationships according to Glaw et al. (2010). However, it is distinguished from this group due to genetic differentiation. There are various other species in Boophis such as B. boehmei, B. rufioculis, and more. Yet, it differentiations itself from these through its larger size and the colors of the iris. The iris does not have red coloring, dark stripes, or blue coloring on the periphery seen in other Boophis species. Also, in many of the Boophis species, there are distinct dermal flaps or tubercles on the heels. Boophis obscurus lacks these. Also, this species is similar to B. periegetes, but they can be differentiated through different skin types, such as containing keratinized spicules rather than large warts and through their advertisement calls. The advertisement calls of B. obscurus contains irregular pulsed croaking (Glaw et al. 2010).

In life, the dorsum is reddish-brown, the flanks are yellow but transition to a blush as they move towards the hips. The dorsum is marked with irregular brown blotches. The ventrum is creamy white with brown markings. The limbs may have orange bars. In preservative, the dorsum color does not change much. The upper lip displays an unconnected cream stripe. Grey warts with tiny black spicules become apparent. The flanks become brown with irregular cream-colored blotches. The legs have dark brown bars. The ventrum becomes beige with brown blotches. The iris of Boophis obscurus are a pale orange (Glaw et al. 2010). There are no remarkable variation in color and pattern in the males from Ranomafana. However dorsal spicules vary in their distinctiveness and the female specimen lacked spicules altogether (Glaw et al. 2010).

Distribution and Habitat

Country distribution from AmphibiaWeb's database: Madagascar

	View distribution map in BerkeleyMapper.
	View Bd and Bsal data (1 records).

This species is endemic to the highlands of the Ranomafana area, which has an elevation of 876 m or 2874 feet, to the Andranoroa River, Ranomafanakely, and Ambatovaky which are all part of the Vohiparara region (Glaw et al 2010).

Life History, Abundance, Activity, and Special Behaviors
next to rainforests. They sit close to each other along borders of canals or shallow water. They have been found above a tree line next to a mountain stream on the ground, perched on branches and rocks in steep areas next to streams, and areas where water constantly flows and drips creating small caves (Glaw et al. 2010).

Vocalization among B. obscurus are variable and contain different call types. However, not enough information has been found on the classification of these call types. One of these calls is assumed to be an advertisement call that is at high energy and regular structure. The call is characterized with a pulsed note with temporal modulation of pulses. Note durations are 137 – 238 ms, repeated at irregular intervals with 8 pulses per note. The intervals between pulses range between 4 – 41 ms and decrease toward the end of the note. The pulse repetition rate varies between 20 – 70 pulses/second. The dominate frequency range is 400 – 3000 Hz. A second call is somewhat similar but is softer more evenly distributed pulses. The note duration is 206 – 360 ms and repeated irregularly with 8 – 16 pulses per note. The interpulse interval is 9 – 25 ms and repletion rate is about 32 – 36 pulses/second. The dominant frequency range is 400 – 1800 Hz. A third type of call contains various single clicks and shorter pulsed notes, but detailed analysis of the call was not possible. These three calls do not seem to follow a pattern and are randomly mixed and combined (Glaw et al 2010).

The reproduction of B. obscurus occurs in streams (Pabijan et al 2012).

Trends and Threats
There is currently no information available for the trends and threats of Boophis obscurus.

Comments
The species authority is: Boettger, O. (1913) Reptilien und Amphibien von Madagascar, den Inseln und dem Festland Ostafrikas, pp. 269–375, Tafeln 23–30, in Voeltzkow, A.: Reise in Ostafrika in den Jahren 1903–1905, Wissenschaftliche Ergebnisse, dritter Band, systematische Arbeiten, Schweizerbartsche Verlagsbuchhandlung, Stuttgart.

The molecular phylogeny places this species in the same clad as Boophis goudoti. The divergences are 2.1-3.9% depending on the length of the fragment. One specimen morphologically belonging to B. obscurus has a sequence identical to B. goudoti indicated incomplete lineage sorting or recent hybridization (Glaw et al. 2010).

Boophis obscurus is one of the first species of frogs identified in Madagascar (Glaw et al. 2010).

This species name is resurrected from Boettger (1913), who named the species, Rhacophorus obscurus (Glaw et al. 2010).

Boophis obscurus is synonymous with Boophis goudoti and Rhacophorus obscurus (Glaw et al. 2010).

References

Glaw, F., Kohler, J., De La Riva, I., Vieites, D.R., Vences, M. (2010). "Integrative taxonomy of Malagasy treefrogs: combination of molecular genetics, Bioacoustics and comparative morphology reveals twelve additional species of Boophis." Zootaxa, 2383, 1-82. [link]

Pabijan, M., Wollenberg, K. C., Vences, M. (2012). ''Small Body Size Increases the Regional Differentiation of Populations of Tropical Mantellid Frogs (Anura: Mantellidae).'' Journal of Evolutionary Biology, 25(11), 2310-2324.

Species Account Citation: AmphibiaWeb 2015 Boophis obscurus <https://amphibiaweb.org/species/7457> University of California, Berkeley, CA, USA. Accessed Nov 23, 2024.

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

AmphibiaWeb's policy on data use.