Description
Rhombophryne botabota is a medium sized frog with a robust body that was described from four adult males, two adult females, and two presumed juvenile males with snout-vent length ranges of 30.2 - 30. 8 mm for adult males, 28.6 mm and 32.2 mm for adult females, and 24.2 mm and 25.4 mm for the two juveniles. The head is wider than it is long with a snout that is rounded dorsally and laterally. The nostrils are more proximal to the eye than the snout tip and are slightly protruding. The canthus rostralis is obvious and concave, as is the loreal region. The pupils are small and circular and the tympanum is not obvious and is round. The horizontal tympanum diameter ranges from 51.0 - 70.5% of horizontal eye diameter. The supratympanic fold is obvious and slightly raised and curves from the posterior corner of the eye, over the tympanum, to the axilla. It lacks superciliary spines. It has thick forelimbs that range from 43.5 - 55.2% of snout-vent length. It has an inner metacarpal tubercle, but does not have an outer metatarsal tubercle. Relative lengths of fingers are 1 < 2 < 4 < 3 . The fingers do not have webbing and the tips of fingers are not enlarged. There is a single, faint subarticular tubercle. There are no nuptial pads. Its hind limbs are also quite thick and, when adpressed along the body, the tibiotarsal articulation reaches the tympanum. The hind limb length is 141 - 164% of snout-vent length. The tibiofibula length is typically 38.4 - 45.7% of snout-vent length while tibiofibular width is 26.5 - 36% of tibiofibular length. The length of the tibia is 38.4% of the snout-vent length. There is a slightly enlarged inner metatarsal tubercle, but the outer metatarsal tubercle is absent. The toes are not webbed and have lengths of 1 < 2 < 5 < 3 < 4. The toes do not have subarticular tubercles and lack enlarged toe tips. Rhombophryne botabota has curved clavicles and maxillary vomerine teeth (Scherz et al. 2016).

DIAGNOSIS:

Rhombophryne botabota is different from all Plethodontohyla species because of the presences of a clavicle in the former. Exceptions are P. mihanika and P. inguinalis, which its differs from by the lack of expanded digital discs and having a dorsolateral color border, and P. fonetana, which it differs from by possessing knob-like terminal phalanges instead of Y-shaped. It can be confused with P. brevipes, however, R. botabota possess a supratympanic fold that is dark, not whitish, and it lacks inguinal spots. These two species also do not overlap in their distributions (Scherz et al. 2016).

Within its genus, R. botabota can be differentiated by coloration, morphology, and call. It has a distinct color border between the dorsum and lateral head distinguishes it from all other Rhonmbophryne species except for R. laevipes. Rhombophryne botabota is differentiated from members of the R. serratopalpebrosa group (R. coronata, R. guentherpetersi, R. ornata, R. serratopalpebrosa, R. tany, and R. vaventy) by the absence of superciliary spines. Rhombophryne botabota is superficially similar to R. guentherpetersi, who has superciliary spines that are very hard to see, however they can be distinguished by the lack of tibia glands in R. botabota. The snout-vent length in R. botabota is larger than R. mangabensis and R. minuta (24.2 - 32.2 mm vs 15.4 - 23.2 mm), and smaller than R. alluaudi and R. laevipes (24.2 – 32.2 mm vs 36.4 – 56.3 mm). Rhombophryne botabota also lacks inguinal ocelli, which are present in R. alluaudi and R. laevipes. It can be distinguished from R. longicrus and R. minuta by front limbs that are shorter (43.5 – 55.2% vs 70.4 – 74.7% of snout-vent length), heftier legs, and a wider head (144.2 – 169.5% vs 122.5 – 142.8%). Furthermore, R. laevipes, R. longicrus, and R. minuta all have longer tibia ( 48.3 – 52.3% vs 38.4 – 45.7% of snout-vent length) and longer hind limb length (175 – 184% vs 141 – 164% of snout-vent length) than R. botabota. It is differentiated from R. coudreaui, R. mangabensis, R. matavy, and R. testudo by having skin that is smoother, having clavicles that are ossified (instead of not ossified, reduced, or absent), and a narrower vertebral transverse processes. Furthermore, R. coudreaui, R. matavy, and R. testudo have shorter tibia (30.3 – 37.2% vs 38.4 – 45.7% of snout-vent length) and have a tibiotarsal articulation that does not exceed the axilla (vs a tibiotarsal articulation that does reach the tympanum and eye in R. botabota). It can be further distinguished from R. mangabensis by its call, which has a higher call repetition rate (inter-call interval 2,359 vs 6,420 ms), a dominant call that is lower in frequency (1272 HZ vs 2800 - 7800 Hz), and has no frequency modulations. Calls can also differentiate R. botabota from its sister species, R. alluaudi as the former has a dominant call frequency that is higher (1,272 ± 13 Hz vs 798 ± 23 Hz) and has a higher fundamental call frequency (621 ± 11 Hz vs 379 ± 34 Hz). Rhombophryne botabota also has a more ossified skeleton than R. alluaudi, does not have fusion of presacral VIII and sacrum, and a dorsal crest of urostyle that only runs 75% of its full length (vs running almost the whole length) (Scherz et al. 2016).

COLORATION:

In preservative, the dorsal side is a light brown and it possesses symmetrical markings behind the scapular region. Each scapula has thin cream colored stripes running over them, and it is faintly striped on the dorsum with dark and light brown lines that run obliquely from the inguinal region to the midline. Inguinal spots are not present. The arms are cream on the ventral side with brown flecks and light brown on the dorsal side. The lower dorsal portion of the arm also has a dark brown cross band. There are fine cream and brown specks on the inside of the hand. The fingers are light brown with some zones of dark brown and cream. It is light brown on the dorsal side of its legs with two dark bands that cross the thigh obliquely, three stripes that cross the shank, and two that cross the tarsus. The anterodorsal portion of the thighs are brown with flecks of cream and the posteriorly is cream, but turns into a dark brown with cream colored eye spots toward the distal regions. The ventral side of the thighs are cream colored with flecks of brown on the anterior and posterior portions. The ventral distal and external portion of the shank is cream with light brown flecks, but becomes brown ocellated with cream approaching the inside of the knee. The ventral side of the tarsus is cream with brown flecks. The external foot is the same color as the tarsus with an area of dark brown. The sole of the foot is brown and has small specks of cream. Toes are speckled with cream and light brown while the tips of the toes are dark brown. The lateral sides of the head are dark brown, which is very distinct from the dorsal coloration. The cloacal region is dark brown. The brown of the dorsum merges on the flanks into the cream color of the ventrum. The ventral belly is an impeccable cream, and its chin is cream colored speckled with brown (Scherz et al. 2016).

VARIATION:

Individuals seem to be consistent in morphology but not in coloration. There is a bit of variation in finger lengths, but the second and fourth finger were generally almost equal. While all specimens have light, thin lines running obliquely across the scapular area, some specimens showed dark spots posterior to these scapular lines. Additionally, posterior inguinal stripes are present in some and absent in others. Ocelli on the posterior thigh are either present, weak, or absent. Thigh cross bands are also not always present. Cross bands on the shank are almost always seen on specimens, but they differ in number and pigmentation. Ventral color is somewhat consistent across all specimens (Scherz et al. 2016).

Distribution and Habitat

Country distribution from AmphibiaWeb's database: Madagascar

View distribution map in BerkeleyMapper.

Rhombophryne botabota have been observed in Northeastern Madagascar and more specifically in Marojejy National Park (Lambert et al. 2017). Specimens have been collected from 860 to 1,326m above sea level in the Sava and Analanjirofo Regions (Scherz et al. 2016).

Life History, Abundance, Activity, and Special Behaviors

The collection of specimens using pitfall traps indicates this is a fossorial species living in underground burrows (Scherz et al. 2016).

The call of this species consists of a sequence of honking notes that are repeated at regular intervals. Call duration is 505 ± 76 ms at 621 ± 11 Hz. The core call is only 151 ± 18 ms due to a long tapering off with the period between calls being 2359 ± 44 ms (Scherz et al. 2016).

Analysis of gut contents indicates that this species feeds on small gastropod snails belonging to Subulinidae and analysis of related species indicates small invertebrates are consumed (Scherz et al. 2016).

In the related species, R. laevipes, colubrid snakes (Liopholidophis) appear to be an important predator and may also feed on this species (Glaw et al. 2007).

Trends and Threats
Rhombophryne botabota, is listed as “Endangered” with a decreasing population trend. This species was categorized as endangered due to its extent of occurrence of 4,190 km², and occurs in less than five threat-defined locations with continuing habitat expanse and quality decline (IUCN 2016). The protected areas in which this species has been found include Makira Natural Park (which is 3,850 km^² of protected forests within community managed protected zones) as well as Marajejy National Park (which is 597.5 km^² of protected forest). The third location, Ambolokopatrika, is currently unprotected (Scherz et al. 2016).

Despite two of the three known localities being fairly well-protected with formal legal protection, the habitat that this species occupies is under threat of deforestation and habitat degradation, and there are still anthropogenic threats (such as mining and the harvesting of hardwood trees) that are compromising the expansivity and quality of the forest habitat. The forest between the protected areas, such as the Anjanaharibe-Sud Special Reserve and COMATSA are also being affected by anthropogenic activities, which may further degrade the habitat for this species (Scherz et al. 2016).

Ambolokopatrika is currently unprotected forest habitat for R. botabota, but is a component of a proposed protected area, which may aid in habitat protection and conservation for this species (Scherz et al. 2016). Other conservation actions proposed include site area protection and management, as well as resource and habitat protection (IUCN 2016).

Possible reasons for amphibian decline

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

Comments

PHYLOGENETIC RELATIONSHIPS:

Bayesian Inference on 545 bp of the mitochondrial 16S rRNA gene fragment identified R. botabota as a member of the R. alluaudi complex with an intraspecific comparison of 10.7%. Rhombophryne botabota is sister to R. alluaudi with the next most closely related clade being composed of R. laevipes, R. mangabensis, R. matavy, R. savaka and R. testudo (Scherz et al. 2016).

ETYMOLOGY:

The species epithet ,“botabota,” is a Malagasy word that translates to “chubby”, which is reflective of the chubby appearance of this frog. This epithet is pronounced as “buddha-buddha” (Scherz et al. 2016).

References

Glaw, F., and Vences, M. (2007). Field Guide to the Amphibians and Reptiles of Madagascar. Third Edition. Vences and Glaw Verlag, Köln.

IUCN SSC Amphibian Specialist Group. (2016). "Rhombophryne botabota." The IUCN Red List of Threatened Species 2016: e.T100339930A100339932. https://dx.doi.org/10.2305/IUCN.UK.2016-3.RLTS.T100339930A100339932.en.

Lambert, S. M., Hutter, C. R., Scherz, M. D. (2017). "Diamond in the rough: a new species of fossorial diamond frog (Rhombophryne) from Ranomafana National Park, southeastern Madagascar." Zoosystematics and Evolution, 93(1), 143. [link]

Scherz, M. D., Glaw, F., Vences, M., Andreone, F., Crottini, A. (2016). "Two new species of terrestrial microhylid frogs (Microhylidae: Cophylinae: Rhombophryne) from northeastern Madagascar." Salamandra, 52(2), 91-106. [link]

Species Account Citation: AmphibiaWeb 2022 Rhombophryne botabota: Chubby diamond frog <https://amphibiaweb.org/species/8487> University of California, Berkeley, CA, USA. Accessed Oct 4, 2022.

Citation: AmphibiaWeb. 2022. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 4 Oct 2022.

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