Rhaebo ecuadorensis Mueses-Cisneros, Cisneros-Heredia & McDiarmid, 2012
|Species Description: Mueses-Cisneros JJ, Cisneros-Heredia DF, McDiarmid RW 2012 A new Amazonian species of Rhaebo (Anura: Bufonidae) with comments on Rhaebo glaberrimus (Guenrhwe, 1869) and Rhaebo guttatus (Schneider, 1799). Zootaxa 3447:22-40.|
Rhaebo ecuadorensis, is a large-sized toad with a body slightly wider than long and a head narrower than its body. It has an SVL of 92.8-127.0 mm in adult males and 156.7 mm in an adult female. Rhaebo ecuadorensis has a snout slightly rounded to truncate dorsally and weakly rounded to truncate from the lateral view. In dorsal view its head is subacuminate. The ratio of the Distance between nostril and tip of snout/ Distance between nostril and eye is 0.12 in the female, and between 0.21-0.31 in males. The tip of the snout is lacking a fleshy vertical ridge.
The nostrils are oval, oblique, directed laterally and open posterior to the anterior rim of the mouth below the canthus rostralis; this area is slightly swollen. The ventral edge of the nostril is straight to concave, while the dorsal edge is rounded. The distance between nostril to nostril/distance between nostril and eye is 1.15-1.22 in males and 1.10 in the female. It is flat from snout to anterior corners of eyelids, and the area between nostrils is flat to weakly concave. The upper eyelid is narrower than the interobital region. The interorbital and occipital regions are flat. These three regions have low slender tubercules. The upper eyelid width/IOD (Inter-orbital Distance)= 0.73-0.79 in males and 0.74 in the female. The outer rim of the upper eyelid does not project beyond the eyes and both the inner and outer rim of upper eyelid are not delineated by tubercles. This species is without a preocular ridge and has low parietal crests (some pronounced in female holotype) but is lacking most cephalic crests. The canthus rostralis is straight and projected over the loreal region; it is fleshy in the female and less so in males. The loreal region is flat to weakly concave with small amounts of regularly distributed spiculae and coni that continue to the post-tympanic region of the toad. There is no preorbital ridge, the lips are not flared, and the eyes have horizontally oval pupils. The entire tympanum is visible in the eyes, and oval-shaped, about 44.2-53.0% of the male eye length and 51.3% of the female eye length. Rhaebo ecuadorensis has a fleshy supratympanic ridge present. It has slightly oval or rounded smooth parotoids with regularly distributed pores. There are no indentations on the outer margin of the parotoids and there are no evident crests on the inter-parotoidal region. The parotoid width is 53.1-61.9% of parotoid length and 59.2-69.9% of inter-parotoid distance in males with 52.7% of parotoid length and 62.6% of interparotoid distance in females (Mueses-Cisneros et al 2012).
There are some small rounded and prominent warts on the postsacral region and some slender and low tubercles in the sacral region while the skin of dorsum is smooth. From parotoids to 2/3 of parotoid-groin distance, there is little evidence of conspicuous warts. There are some low tubercles mainly on throat and chest but overall the ventral skin is smooth. The forearms are long and somewhat robust with warts in adult males. They have spiculae and coni on upper surface and flanks. The hand length is 24.8-29.2% of SVL in males and 23.9% in females. The fingers have fleshy and bulbous tips without webs with finger I longer than II. There are a few rounded and low super-numerary palmar tubercles and rounded, evident subarticular tubercles. The palmar tubercle is rounded and large. It is 1.2-1.5 times as large as a rounded thenar tubercle. There are no ulnar tubercles, no metacarpal fold, and no ulnar fold present (Mueses-Cisneros et al 2012).
The hind limbs are long with somewhat robust thighs. The inner tarsal is fleshy and has an evident fold that is 1/2 to 1/3 the tarsal length. The upper surface has spiculae and coni extending up the thighs with some warts. There are no tubercles on the outer edge of tarsus. The foot and tibia lengths are 35.9-41.8% of SVL in the males and 37.7% and 43.9% in the female. The toes are basally webbed and have bulbous, fleshy tips. There are low, round and scarce supernumerary plantar tubercles. Both musculus adductor longus and omosternum are present.
The tongue is not notched posteriorly and is rounded with 2/3 of its extension adherent to the floor of its mouth. The males have small subgular vocal sacs with vocal slits posterior and lateral to the tongue. The choanae is large; oval to rounded, and is not hidden by palatal shelf of maxillary arch. There are nuptial pads on fingers I and II that are dark brown or cream. Cloacal opens towards the middle level of thighs (Mueses-Cisneros et al 2012).
Coloration in life: The coloration of the dorsal background varies from orange-brown or olive-brown to pale to dark brown. Low, dark brown to black warts scattered on dorsal surfaces in many specimens. Among examined specimens, the parotoid glands are slightly paler than dorsal. On the sides of the head, tympanic area, arms, legs, flank, and groin the background coloration is dark brown to black usually with pale low warts. This is especially true on the posterior flanks and upper lip of the toad. Rhaebo ecuadorensis also has white to cream-colored postrictal warts. If the legs are pale brown, there usually have dark brown spots that sometimes form into indistinct bands. The throat and chest background color varies from dark brown to black and marbled with cream or white that varies on the venter from dark brown to tan-cream. There are white post-cloacal warts and concentrated around the golden circumpupillary ring it is iris black with abundance of bronze to golden punctuations (Mueses-Cisneros et al 2012).
Coloration in preservative (70% ethanol): Laterally, the parotoids are dark brown to black in most specimens and yellowish-brown dorsally but sometimes juveniles have the same dorsal coloration throughout. The dorsum is light to dark brown and the sides of head are light brown. The dorsal and flank color are sharply-separated and the body flanks are dark brown. The arms and legs sometimes have indistinct dark bands and are black or dark brown with or without dark to black warts. The venter is cream to dark brown or dark brown with some irregular cream stain and the throat and chest are dark brown to grey, marbled with cream (Mueses-Cisneros et al 2012).
Distribution and Habitat
Country distribution from AmphibiaWeb's database: Bolivia, Brazil, Colombia, Ecuador, Peru
Life History, Abundance, Activity, and Special Behaviors
Natural history: Thus far, R. ecuadorensis has been found after heavy rains and are commonly found on the leaf litter. In the Province of Orellana, Ecuador, at the Tiputini Biodiversity Station, this species was usually found in the leaf litter near small creeks during the late afternoon and early evening in Evergreen Non-Flooded forests. Two specimens were collected on a paved road. Another specimen that exuded a yellow excretion from the parotoid glands was collected at the margin of a 3 m wide stream. The fourth specimen was found on leaf litter. Other specimens were mostly found among stones in the river bands and under trunks (Mueses-Cisneros et al 2012).
Etymology: This new species name Rhaebo ecuadorensis is to honor the Republic of Ecuador and to be a tribute to its natural diversity and its people. Ecuador is one of the 10 megadiverse countries in the world even though it is one of the smallest countries in South America. The ability to examine the Ecuadorian material allows us to find the existence of species that have not yet been described such as this one that was previously confused with Rhaebo glaberrimus and Rhaebo guttatus (Mueses-Cisneros et al 2012).
Trends and Threats
Conservation Status: Data Deficient (DD) because there is not enough information this species current state and knowledge about their habitat is very limited.
With the discovery of R. ecuadorensis, there are now currently ten species classified under the genus Rhaebo. This has changed previous notions of the geographic distribution of Rhaebo glaberrimus and Rhaebo guttatus. In Ecuador, this is the sixth species found of the genus Rhaebo (Mueses-Cisneros et al 2012).
Recently a specimen of Rhaebo was collected in Taisha, Provincia de Morona Santiago in Ecuador, which is similar in appearance to R. ecuadorensis. It was an adult female with numerous eggs and a SVL of 94.0 mm, much smaller than the female holotype. There are no other differences other than this SVL to classify this species as separate from R. ecuadorensis, so for now the authors recognize it as R. ecuadorensis (Mueses-Cisneros et al 2012).
Other species that are similar to R. ecuadorensis are R. glaberrimus and R. guttatus. R. ecuadorensis is often mistaken for a juvenile R. guttatus. R. glaberrimus is found in Colombia and Venezuela and is often found in similar leaf litter to R. ecuadorensis. R. guttatus is found in Brazil, Bolivia, Colombia, Ecuador, Venezuela and the Buianas. R. guttatus has a presences of a prominent preocular ridge and a distinct ventral pattern with rounded light spots. Because both R. guttatus and R. glaberrimus are found in Colombia, there are often mistakes in identification. R. Glaberrimus is found in the eastern flank of the Cordelliera Oriental, not the Pacific Region. R. glaberrimus is physically different from other species of Rhaebo because it has a cloacal opening ventrally in males and near the interior part of the thighs in females. R. ecuadorensis does not have a perocular ridge and it ventrally differs from the coloration of R. guttatus. R. guttatus has a brown dorsum with dark greyish brown spots (Mueses-Cisneros et al 2012).
Mueses-Cisneros, J.J., Cisneros-Heredia, D.F., McDiarmid R.W. (2012). ''A new Amazonian species of Rhaebo (Anura: Bufondae) with comments on Rhaebo glaberrimus (Gunther, 1869) and Rhaebo guttatus (Schneider, 1799).'' Zootaxa, 3447, 22-40.
Originally submitted by: Amanda Chiachi (first posted 2012-10-30)
Edited by: Michelle S. Koo (2013-03-12)
Species Account Citation: AmphibiaWeb 2013 Rhaebo ecuadorensis <https://amphibiaweb.org/species/7897> University of California, Berkeley, CA, USA. Accessed Oct 1, 2023.
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Citation: AmphibiaWeb. 2023. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 1 Oct 2023.
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