Description

Diagnosis: Distinguished by the combination of notched digital discs, narrow head, lack of vomerine teeth, lack of nuptial pads in males, green coloration, paired gland-like protrusions on the dorsum, distinct subconical tubercle on the upper eyelid and on the heel, and a tarsus bearing a row of conical tubercles on its outer edge.

Description: The snout-vent length (SVL) in the single adult male specimen is 19.8 mm and in the single subadult female it is 19.5 mm. The head is longer than wide, and narrower than the body with the widest point anterior to the angle of the jaw. Cranial crests are lacking. The braincase is not well ossified and parts of it remain cartilaginous; the nasal region also lacks ossification. The snout is moderately long, rounded in dorsal view and bluntly rounded in profile, with a slightly curved canthus rostralis and a concave loreal region. Eye-nostril distance is 80% that of the diameter of the eye. Each upper eyelid has a subconical tubercle. Nostrils protrude just slightly. Lips are rounded. The side of the head is vertical. The tympanic membrane is differentiated and the tympanic annulus is smooth, low, and round with a diameter of approximately 40% of the eye. It is separated from the eye by a distance of approximately twice the diameter of the eye. Posterior and ventral to the tympanum is a rounded postrictal tubercle. The supratympanic fold barely covers the tympanum's posterodorsal edge. In comparison to members of the family Strabomantidae (which they resemble morphologically), members of the family Ceuthomantidae have no dentigerous processes of the vomers. The oval-shaped tongue is broadest on the posterior end, not notched, and free posteriorly for about half of its length. The oval-shaped choanae are not obscured by the palatal shelf of the maxillary. The skin on the dorsal side is smooth and on the ventral side is areolated, while the throat is slightly granular. The cloacal sheath is short and is not laterally bordered by a fold or tubercles. There are no dorsolateral folds or discoid folds. The frog has dorsal glandlike structures of unknown function in the scapular region (less pronounced in the juvenile specimen) and also the sacral region. This species has anteriorly notched digital discs on the broadly expanded tips of fingers (toes also have expanded discs approximately the same size). There is no ulnar tubercle but the heel has a subconical tubercle and there is a row of conical tubercles on the outer edge of the tarsus. There are no plantar supernumerary tubercles. There is also no inner tarsal fold. There is an inner metatarsal tubercle that is ovoid and is three times the size of the subconical outer metatarsal tubercle. The thenar tubercle is elliptical and slightly elevated, much larger than the bifid palmar tubercle. There are also subarticular tubercles that are low and rounded. Fingers and toes lack lateral fringes. The relative finger lengths are IIn life, the dorsal surface is a dull olive brown with black markings. Limbs have black transverse bars and there is also a black longitudinal stripe on the inner forearm. The head bears a prominent bright green interorbital bar, black labial bars, and a black canthal stripe, below which runs a distinct green bar. The dorsum has a pair of diagonal scapular marks. The venter is creamy gray with extensive black mottling and the throat is almost completely black (mottled in the female and juvenile specimen, black in the male specimen). The dorsal surfaces of the finger discs are white, whereas that of the toe discs are creamy white with some black in the terminal notch. The iris is greenish bronze with numerous black flecks.

In preservative, the dorsal surface is tan with irregular paravertebral markings. The bright green marks become pale gray. The limbs become tan with brown transverse bars rather than gray. The belly is cream-colored with irregular brown spots. Ventral surfaces of the hind limbs are brown with creamy spots. Posterior thigh surfaces are brown. The palmar and plantar surfaces are black (Heinicke et al. 2009).

Distribution and Habitat

Country distribution from AmphibiaWeb's database: Guyana

View distribution map in BerkeleyMapper.

Ceuthomantis smaragdinus is known from Guyana, at elevations of 1490 - 1540 m. This species has been found on two of the Guiana Shield's easternmost mountains: Mt. Ayanganna and Mt. Kopinang, in the Wokomung Massif. The habitat at the type locality is cloudforest, with broad-leafed trees about 12 m tall, shrubs, and scattered small tree ferns, all covered with epiphytic moss and bromeliads. A frog (male) was collected from a leaf that was 1.5 m above the ground and 5 m from a stream, sheltered by another leaf from heavy rain. Another frog (female) was found during a light rain on a leaf 10 m from the stream. A juvenile frog was found at night among leaf litter on the ground in a dense low-canopy forest (Heinicke et al. 2009).

Life History, Abundance, Activity, and Special Behaviors
Calls were heard during the day at the type locality and assumed to be from C. smaragdinus, although the author states that at least eighteen other anuran species also occur at the type locality. Members of the family Ceuthomantidae may share the unusual trait of diurnal calling (unusual for terraranans); C. cavernibardus has been confirmed to call during the day and C. aracamuni has been found during the day on moss and rocks in a small creek (Heinicke et al. 2009).

It is assumed that this species has terrestrial breeding and direct development of the terrestrial eggs, though this has not been confirmed; the sole female specimen was a subadult which had small, unpigmented eggs in the ovaries (Heinicke et al. 2009).

Trends and Threats
Unknown at present.

Comments
The family name, Ceuthomantis derives from Greek roots: keuthos, meaning hidden (alluding to its hidden habitat in the tepuis), and mantis, meaning treefrog. The species name smaragdinus comes from Latin roots and means emerald green, referring to the marks on its head and body (Heinicke et al. 2009).

References

Heinicke, M. P., Duellman, W. E., Trueb, L., Means, E. B., MacCulloch, R. D., and Hedges, S. B. (2009). ''A new frog family (Anura: Terrarana) from South America and an expanded direct-developing clade revealed by molecular phylogeny.'' Zootaxa, 2211, 1-35.

Species Account Citation: AmphibiaWeb 2011 Ceuthomantis smaragdinus <https://amphibiaweb.org/species/7378> University of California, Berkeley, CA, USA. Accessed Dec 3, 2024.

Citation: AmphibiaWeb. 2024. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 3 Dec 2024.

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