Description

DESCRIPTION:

Boophis sandrae is a slender-bodied frog with males having a snout-vent length range of 35.5 - 48.2 mm and females having a range of 50.3 - 63.0 mm. They have a long head, which is wider than its body. Their nostrils are slightly closer to the eyes than the snout, which appears to be round from a dorsal view. Boophis sandrae has a distinct tympanum. The dorsal side of its body has smooth skin while it is very slightly granular on its throat and coarsely granular on its chest and stomach. The limbs are relatively small in size. They have round, single subarticular tubercles and hidden metacarpal tubercles. They have slightly enlarged toe disks, moderately webbed fingers with lateral dermal fringe, and has a nuptial pad on the inside of the first finger. The relative finger lengths are 1 < 2 < 4 < 3 and the relative toe lengths are 1 < 2 < 5 = 3 < 4. Calling males have a bilobed subgular vocal sac (Glaw et al. 2010).

DIAGNOSIS:

Boophis sandrae has been described as almost identical to the B. elenae, which has an overlapping geographic range. The main difference between the two species is that the B. elenae has a reddish horizontal stripe in the iris, which B. sandrae lacks. Boophis sandrae also has a smaller body size and faster call with a shorter note duration and higher note repetition rate. Additionally, whereas most Boophis species calls consist of a series of melodious whistling notes or a slow series of pulsed notes, B. sandrae’s calls consist of a long series of short and unharmonious notes (Glaw et al. 2010).

COLORATION:

In life, B. sandrae has light green coloring on the upper surface of the head and dorsum with darker green spotting. On its upper eyelid, tympanic region, upper lip, loreal region, and around parts of the hind limbs it has a blue coloration. On the mid-flanks this species has a gray stripe that is above an unpigmented area of the body. Its lateral fringes are white, fingers green and webbing yellow. The posterior edge of the iris is light blue with a black border on on either side of it (Glaw et al. 2010).

Once preserved, most of its body turns a cream color with the area above the eye remaining black (Glaw et al. 2010).

VARIATION:

There is sexual dimorphism, with females being typically larger. While most specimens had the same coloration and patterning, one female had more yellow dorsal coloration and three yellow spots between the eyes. The females have light bands on their limbs and a translucent bluish green coloration on the ventral surfaces of their limbs. She also had pale pink irises (Glaw et al. 2010).

Distribution and Habitat

Country distribution from AmphibiaWeb's database: Madagascar

View distribution map in BerkeleyMapper.

Boophis sandrae is found in the Ranomafana National Park region of southeastern Madagascar, including Ambatolahy forest, and the villages of Ranomafana and Vohiparara at elevations of 619 - 1152 m asl. Although they can be heard calling in dense rainforest, they are more commonly found at forest edges, in secondary or degraded forest, and in large trees along streams and rivers in cleared areas (Glaw et al. 2010, IUCN 2015).

Life History, Abundance, Activity, and Special Behaviors
Most Boophis species are arboreal ‘tree-frogs,’ including B. sandrae. Calling B. sandrae are usually perched on thin branches of large trees 2 - 4 m above the ground (Glaw et al. 2010).

Generally, calls of B. sandrae consist of an extended series of rapidly repeated short pulsed notes. Some records even show a single call lasting 33.6 - 45 seconds. The notes have 3 - 7 distinct pulses that increase in amplitude, a note duration of 13 - 34 ms, inter-note intervals of 14 - 43 ms, a repetition rate of 22 notes per second, and a dominant frequency of 2150 - 3600 Hz (Glaw et al. 2010).

Boophis sandrae can be observed engage in axillary amplexus in lower vegetation from calling perches along streams during the evening (Glaw et al. 2010).

They have been found in sympatry with B. luteus, but at the time of the species description, was not found in the same stretches of stream as B. elenae despite having a range overlap (Glaw et al. 2010).

Trends and Threats
While B. sandrae occurs frequently within and in the surrounding region of Ranomafana National Park, it is suspected that the population is currently declining. The primary driver of this suspected decline, and an ongoing threat, for this species is habitat degradation and fragmentation resulting from various forms of intensive land development. Currently, the expansion of agricultural development, mining, and urbanization are the most significant forms of land degradation that contribute to B. sandrae population decline. However, the species' range includes Ranomafana National Park, which, as of 2010, is well managed but vulnerable to weakened enforcement (IUCN 2015).

Possible reasons for amphibian decline

General habitat alteration and loss
Habitat modification from deforestation, or logging related activities
Intensified agriculture or grazing
Urbanization
Mining
Habitat fragmentation

Comments

PHYLOGENETIC RELATIONSHIPS:

Maximum Parsimony analysis of 16S rRNA indicate that B. sandrae is sister to a clade composed of B. anjanaharibeensis and tadpoles that were assumed to be B. sandrae from the Andasibe region (Glaw et al. 2010). Those tadpoles were later described, in a Maximum Likelihood analysis of the same gene, as B. asquithi and another yet to be described species. The 2010 analysis indicates that next most closely related species is B. septentrionalis (Glaw et al. 2010) while the 2021 analysis found that the clade composed of B. andohahela, B. andreonei, B. elenae, and B. septentrionalis was the next most closely related (Glaw et al. 2021).

ETYMOLOGY:

The species epithet “sandrae” is a recognition of Sandra Nieto Románg for her various contributions during field work and research in the laboratory, by her husband, Dr. David R. Vieites, one of the researchers who described B. sandrae (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]

Glaw, F., Köhler, J., Crostini, A., Gehring, P.-S., Prötzel, D., Randriamanana, L., Andreone, F., Vences, M. (2021). “An additional level of cryptic diversity: a new green-coloured Malagasy treefrog of the Boophis luteus species group.” Salamandra 57(3), 295 - 308. [link]

IUCN SSC Amphibian Specialist Group. (2015). "Boophis sandrae". The IUCN Red List of Threatened Species 2015. https://doi.org/10.2305/IUCN.UK.2015-4.RLTS.T49545926A49545978.en.

Species Account Citation: AmphibiaWeb 2022 Boophis sandrae <https://amphibiaweb.org/species/7459> University of California, Berkeley, CA, USA. Accessed Nov 21, 2024.

Citation: AmphibiaWeb. 2024. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 21 Nov 2024.

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