Description

Diagnosis: Ceuthomantids share five characters: (1) notched digital discs; (2) narrow heads; (3) green coloration; (4) absence of vomerine teeth; (5) absence of nuptial pads (though the holotype of C. aracamuni may be a subadult male and thus could not have nuptial pads). Ceuthomantids also lack intercalary elements and Bidder's organs (Heinicke et al. 2009).

Ceuthomantis aracamuni can be diagnosed by the following combination of characters: (1) areolate dorsum, finely areolate venter; (2) distinct, rounded tympanum, 1/2 the diameter of the eye; (3) snout truncate in lateral view, subovoid in dorsal view; (4) upper eyelid lacks tubercles and is 63% wider than distance between orbits; (5) cranial crests lacking; (6) small, round choanae; (7) no vomerine teeth; (8) rounded tongue; (9) males have vocal slits but are thought to lack nuptial pads (though the holotype might have been a subadult male); (10) Finger I shorter than Finger II; (11) Fingers III and IV with enlarged discs that have a medial notch; (12) no lateral keels on fingers; (13) no axillary tubercles; (14) no ulnar tubercles; (15) calcars absent; (16) tarsal fold absent; (17) oval inner metatarsal tubercle that is 2x the size of the round outer metatarsal tubercle; (18) toes without webbing or keels; (19) Toes III-V with broad discs that have a medial notch; these discs are smaller than those of Fingers III-IV; (20) coloration in preservative: pale brown dorsum with diffusely reticulated dark brown and white markings; eyelids gray; canthal and supratympanic dark brown stripes; dark brown bars on the lip; white venter with numerous melanophores that transition into dark brown gular spots; apparent median white stripe in the gular region (Barrio-Amorós and Molina 2006).

Description: Snout-vent length of the subadult or adult male holotype is 18.2 mm. Maximum adult length is unknown. The head is longer than wide, but still wider than the body. No cranial crests are present. The snout is subovoid in dorsal view and truncated in profile, with a distinct and rounded canthus rostralis and slightly concave loreal region. Choanae are small and round. Vomerine teeth are lacking. The tongue is round, with the posterior half free. Orbitonarial distance is 69% that of the diameter of the eye. Nostrils do not protrude. The upper eyelid is wider than the interorbital distance (by 63%) and lacks tubercles. The tympanum is distinct, round, and superficial, with a diameter just under half that of the eye (45%). Behind and slightly below the tympanum are flat warts. A weakly developed supratympanic fold is present. There is a middorsal raphe (skin ridge), but dorsolateral folds are absent. The dorsal skin is areolate; the ventral skin is finely areolate. The throat is smooth. Axillary and ulnar tubercles are both lacking. Relative adpressed finger lengths are III>IV>II>I. Fingers lack lateral keels but have expanded discs, with the disc on Finger I smaller than those on Fingers II, III, and IV. Finger I is also very short, not even reaching to the disc on Finger II. Fingers III and IV bear medially notched discs. The ungual flap has a deep V-shaped notch. The palmar tubercle is flat and bifid, and larger than the oval-shaped thenar tubercle. Subarticular tubercles are single, round, and flat. Supernumerary tubercles are lacking. No axillary tubercles are present. Hind limbs are long, with the heels overlapping the snout tip when pressed to the sagittal plane. The tibia is 60% the snout-vent length. Calcars are lacking. No tarsal fold is present. The inner metatarsal tubercle is oval-shaped and much larger than the indistinct, round outer metatarsal tubercle. Relative adpressed toe lengths are IV>V>III>II>I. Toes III, IV, and V have discs, but they are smaller than those on Fingers III and IV. The disc on Toe IV is distinctly narrower than the disc on Finger III; also, the ungual flap has a notch. Toes lack both webbing and keels. There is no tarsal fold (Barrio-Amorós and Molina 2006).

Similar species:
--C. smaragdinus: C. aracamuni lacks paired dorsal gland-like protrusions, unlike its congener C. smaragdinus; in C. smaragdinus, a pair of gland-like structures is present on the posterior of the head and also in the sacral area. C. aracamuni also does not have the distinct subconical tubercle on the upper eyelid and the heel that are present in C. smaragdinus. In addition, C. aracamuni lacks the row of tarsal conical tubercles that is present in C. smaragdinus (Heinicke et al. 2009).

--C. cavernibardus: C. aracamuni can be distinguished from C. cavernibardus by dorsal skin texture (areolate in C. aracamuni vs. granular to weakly tuberculate in C. cavernibardus); a shorter first finger (Finger I is 86% of the length of Finger II in C. aracamuni, vs. 94% in C. cavernibardus); a narrower head (34% of SVL in C. aracamuni vs. 37-41% of SVL in C. cavernibardus); snout profile (strongly truncate in C. aracamuni vs. rounded in C. cavernibardus) (Barrio-Amorós and Molina 2006).

In life, the, the dorsum is yellowish green with brown spots. The dorsal surface of the limbs is reddish brown with green. The canthal stripe is brick red. The supratympanic stripe is ochre. The belly is blackish brown with white spots (Barrio-Amorós and Molina 2006).

In preservative, the dorsal color is pale brown with diffuse reticulated dark brown markings and a few white marks. The eyelids are gray. There are dark brown canthal and supratympanic stripes. Dark brown lip bars are present. The ventral color is white, suffused with melanophores. The gular region has dark brown spots and a median white stripe. The palms and soles are brown with white markings (Barrio-Amorós and Molina 2006).

Distribution and Habitat

Country distribution from AmphibiaWeb's database: Venezuela

View distribution map in BerkeleyMapper.

This species has been collected and described from the summit of Cerro Aracamuni, a granitic mountain in the northern part of the Neblina massif, in the state of Amazonas, Venezuelan Guiana, at 1493 m asl. This tepui reaches a maximum of 1600 m in elevation. The holotype and paratype were found during the day on a mossy rock pile in a small creek within dwarf gallery forest (Barrio-Amorós and Molina 2006).

Life History, Abundance, Activity, and Special Behaviors
The holotype and paratype were not calling when captured (the paratype at least is a juvenile, of undetermined sex, and the holotype may be a subadult male). Both were found during the day, sitting on a mossy patch on a rock talus pile in a small stream (2 m wide). The forest at the type locality is dwarf gallery forest, with canopy height only 2.5 m above the forest floor. Only one other amphibian (Cochranella riveroi) is known from Aracamuni (Barrio-Amorós and Molina 2006). The species has an unusual behavior for terraranans of diurnal calling (assumed from hearing calls in the locality of this species) (Heinicke et al. 2009). The species has terrestrial breeding and direct development of the terrestrial eggs. They also possess embryonic egg teeth (Barrio-Amorós and Molina 2006).

Comments
The original description of the species (as Eleutherodactylus aracamuni, Barrio-Amoros and Molina 2006) was made based on a subadult or adult male and a juvenile of unknown gender. Normally, the description of a new species would not be based on juvenile samples alone, but tepuis are difficult and expensive to access for field studies and it is not likely that more specimens would be soon obtained from Aracamuni. This species is very similar to C. cavernibardus. Since the juveniles of C. cavernibardus resemble adults, it is assumed that juveniles of C. aracamuni likely also resemble adults of the same species (Barrio-Amorós and Molina 2006).

The family name Ceuthomantis derives from the Greek words keuthos, meaning "hidden" (alluding to its hidden habitat in the tepuis), and mantis, meaning "treefrog" (Heinicke et al. 2009). The species name, aracamuni, refers to the locality: the summit of Cerro (tepui) Aracamuni (Barrio-Amorós and Molina 2006).

Phylogenetic analysis based on 17 genes (11 nuclear and 6 mitochondrial) showed that this family represents the most basal lineage within the Terrarana (direct-developing frogs) (Heinicke et al. 2009).

References

Barrio-Amorós, C. L. and Molina, C. R. (2006). ''A new Eleutherodactylus (Anura, Brachycephalidae) from the Venezuelan Guayana, and redescription of Eleutherodactylus vilarsi (Melin).'' Zootaxa, 1302, 1-20.

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 2010 Ceuthomantis aracamuni <https://amphibiaweb.org/species/6796> University of California, Berkeley, CA, USA. Accessed Nov 22, 2024.

Citation: AmphibiaWeb. 2024. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 22 Nov 2024.

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