Description
Cardioglossa annulata is a slender frog. The single described male specimen has a snout-vent length of 22.8 mm. The four female paratypes have snout vent lengths ranging from 30.0 - 32.9 mm. A single juvenile paratype has a snout-vent length of 21.5 mm. The body is elongated with a snout that is pointed from a dorsal view and nearly truncated from a lateral view. The canthus rostralis is rounded and the loreal region is flat. The tympanum are prominent. The distance from the eye to snout tip is roughly equal to the maximum diameter of the eye. The external nares are far from the eye and close to the snout tip. All of the extremities are long and thin. However, the thighs are shorter than the feet. The fingers and toes are pointed and have one subarticular tubercle that spans the digit width. The digits do not have disks. Neither the palms nor the feet have webbing. The hands have egg-shaped palmar tubercles. The relative finger lengths are II < I < IV < III, and the third finger is very elongated and has spines running down its entire length. One smaller spine is on the lateral side of the second finger. The relative toe lengths are I < II < V < III < IV, and the feet also have egg-shaped inner metatarsal tubercles approximately as long as the smallest toe. The snout, loreal region, and ventral surfaces are all smooth, while the dorsal skin is slightly granular. The skin of the groin, dorsal thigh, and lower back have small white spines (Hirschfeld 2015).

Cardioglossa annulata differs most apparently from similar species through its markings. It does not have the back markings (in either an hour glass shape or three large spots) that most other Cardioglossa species have. Of the few other Cardioglossa species that do not have back markings (Cardioglossa congolia, Cardioglossa oreas, Cardioglossa manengouba, Cardioglossa pulchra, and Cardioglossa venusta), Cardioglossa annulata is distinguishable by its infratympanal line. More specifically, Cardioglossa annulata differs from Cardioglossa congolia and Cardioglossa gratiosa through black bars with yellow borders on its front and hind limbs and a flashy black mask that runs laterally from the snout to midbody. Compared to Cardioglossa congolia, Cardioglossa annulata has a dark and light pattern on its back. Cardioglossa annulata looks most like Cardioglossa gratiosa, but does not have the latter’s black transverse stripes on its extremities or patterned lateral coloration (Hirschfeld 2015).

In life, the holotype has a brown back with three small black spots. The limbs have transverse black stripes (two on the forelimbs and nine on the hind limbs). Between these stripes are brown patches edged with a thin, light line, and ventral stripes are separated by yellow patches. The posterior thigh is black. A black mask covers the tympanum and runs posteriorly from the snout to the last third of the body. A black spot covers the groin. Dark markings on the flank and hind limbs are ringed with a creamy yellow line that blurs as it moves dorsally. The back is brown/gray and has irregular yellow spots. The throat is dark gray. The spines on the fingers, groin, dorsal thigh, and lower back are white. In preservative, the patterns fade slightly over time (Hirschfeld 2015).

The species’ back coloration can vary from light to dark brown, and black spots on the back can also vary in number and size. Although the majority of individuals have nine black bars on their legs, the size of the bars varies. The ventral spots also differ in their number and coloration (between white and yellow). The infratympanal white stripe can be distinct or faded, and can thicken or break off below the tympanum. The females had a slightly lighter throat than the male specimen (Hirschfeld 2015).

Distribution and Habitat

Country distribution from AmphibiaWeb's database: . Introduced: Congo.

View distribution map in BerkeleyMapper.

All of the five specimens were collected from the Niari Department of the Republic of the Congo in Africa. The elevational range of the specimens was 634 - 744 m. The known range is contained within the moist rainforest zone of the Republic of the Congo. Most of the specimens were found or trapped along small rivers in secondary or degraded rainforest. Some individuals were found on plants or logs or on the forest floor in muddy or marshy areas (Hirschfeld 2015).

Life History, Abundance, Activity, and Special Behaviors
Although information on Cardioglossa annulata’s breeding preferences, tadpoles, and calls is not currently available, these traits are most likely similar to those of other species in the genus (Hirschfeld 2015).

Comments
The species authority is: Hirschfeld M, Blackburn DC, Burger M, Greenbaum E, Zassi-Boulou A-G, and Rödel M-O. 2015. Two new species of long-fingered frogs of the genus Cardioglossa (Anura: Arthroleptidae) from Central African rainforests. African Journal of Herpetology 64(2), 81-102.

Cardioglossa annulata forms a subclade within Cardioglossa with Cardioglossa escalerae, Cardioglossa gratiosa, Cardioglossa nigromaculata, Cardioglossa trifasciata, and Cardioglossa congolia. Pairwise genetic comparisons of the mitochondrial 16S rRNA gene suggests a low to moderate level of divergence between Cardioglossa annulata and other closely related Cardioglossa species (Hirschfeld 2015).

The species epithet, “annulatus”, comes from a Latin version of annulated, or having rings, which refers to the color pattern of the species’ hind limbs and their black stripes (Hirschfeld 2015).

Floodplains adjacent to the Congo and Ubangi Rivers may act as geographic barriers for Cardioglossa annulata and other similar species (Hirschfeld 2015).

References

Hirschfeld M, Blackburn DC, Burger M, Greenbaum E, Zassi-Boulou A-G, and Rödel M-O (2015). ''Two new species of long-fingered frogs of the genus Cardioglossa (Anura: Arthroleptidae) from Central African rainforests.'' African Journal of Herpetology, 64(2), 81-102.

Species Account Citation: AmphibiaWeb 2016 Cardioglossa annulata: Annulated Long-fingered Frog <https://amphibiaweb.org/species/8378> University of California, Berkeley, CA, USA. Accessed Oct 11, 2024.

Citation: AmphibiaWeb. 2024. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 11 Oct 2024.

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