Description
Cardioglossa occidentalis is an African frog with an elongated body and extremities. The male snout-vent length range is 25.4 – 27.3 mm and female range is 26.2 – 30.3 mm. The snout is long and round. The nostrils are at the tip of the rostrum. The canthus rostralis is somewhat rounded. The distance between the eyes is about equal to the diameter of the eye and they are located close to the rostrum. Members of this species are equipped with a large, prominent tympanum. On the palms, there is a prominent, nearly conical palmar tubercle. As with other species in the genus, males possess the characteristic elongated third digit on each hand that is twice the length of the second digit. Prominent spines can be found lengthwise along the middle of the dorsal surface of the third finger between the metacarpal-phalangeal joint and fingertip. The spines begin as a single row and split into two rows toward the tip. There are also two smaller spines on the base of the second finger on the lateral surface. The finger pads show no significant enlargement in males. The femur and tibia are about equal in length. The toe pads also show no significant enlargement, and the feet lack webbing. The skin on the snout, loreal region, and ventral surfaces is smooth, while the dorsal skin is slightly granular. Males possess small conical spines along the caudal region of the dorsum, inguinal area, and proximal thigh (Blackburn et al. 2008).

Cardioglossa occidentalis tadpoles lack labial teeth and have very small eyes that are located laterally. Their spiracle looks like a transparent funnel that projects posteriorly. They are dorsoventrally flattened and their tail is twice their body length. Tadpoles are found in the leaf litter of small streams (Blackburn et al. 2008).

Cardioglossa occidentalis can be differentiated from other Cardioglossa species by five distinct characters. The first is the fusion or near fusion of the markings of their three dorsal lobes. Secondly, there is white line extending anteriorly from the arm, below the tympanum to just below the eye. Thirdly, it has a dark mask that is rimmed with white and continues, unbroken, from the eye to the edge of the dorsal scapular lobe. Fourthly, the lateral portions of the body are covered in a few large, dark spots rimmed by a thin white line. And lastly, the belly is covered in lightly colored spots, some also rimmed by an ill-defined white line (Blackburn et al. 2008).

Cardioglossa occidentalis is morphologically and biologically similar to C. leucomystax, from which it was split in 2008. It can be differentiate by the length of the infratympanal line and loreal mask. Specifically, the former has a white line that runs along the tympanum and ends directly under the eye while the latter has a line that extends to the nostril. And the loreal mask on C. occidentalis extends further without being broken than C. leucomystax and has larger blotches when it does break. Additionally, C. occidentalis have larger and fewer spots on the ventrum than C. leucomystax. Biologically, both species are widespread in low elevations (which exclude all other Cardiogolossa), have similar male chorus sizes, and prefer small forest streams with sandy soils. However, the two species differ biological by C. occidentalis breeding mostly in the wet season and preferring primary forest while C. leucomystax is assumed to breed during the dry season and can be found in both primary and secondary forests (Blackburn et al. 2008).

Cardioglossa occidentalis can be differentiated from C. melanogaster and C. schoetzi by having unfused first and second vertebrates (Blackburn et al. 2008).

In life, the basic color for all individuals ranges from gray to a deep brown. On the loreal region there is a black mask that extends posteriorly along the side of the head, covering the tympanum, behind the arm, to the scapula. On the posterior side the mask is broken into large black spots rimmed with white. The white line is most visible along the ventral side of the mask and ends below the eye. There is a dark diamond shaped spot connected to an hourglass shaped pattern that covers the cephalic, scapular, and lumbar regions. The diamond is on the head region from the back from the rostrocaudal midline of the eyes to the level of the arm insertion. After a small gap, the hourglass pattern begins with a diamond shaped lobe over the scapular region that fused with the fat “V” shaped lumbar lobe. There are small dark spots irregularly scattered over the dorsum. On the forearm, thigh, leg, and ankle, there are two dark brown transverse bars that are bordered by a thin white line. The posterior surface of the thigh has an irregular, thick, black line that runs proximodistally. There is also a black spot on the inguinal region. The small conical spines found on the male caudal region of the dorsum, inguinal area, and proximal thigh are grayish-white. The background color of the ventrum is brownish-grey and there are many large irregular brown blotches on the surface. The background color on the throat of males is brownish-violet and also has brownish blotches. When preserved, the color and patterns fade slightly (Blackburn et al. 2008).

There is mild sexual dimorphism, with females being larger than males, having swollen fingertips, and having slightly expanded toe tips. Furthermore, females typically possess a gular region that is lighter than that of males. Males also have grayish-white conical spines on their caudal, inguinal, and proximal thigh regions (Blackburn et al. 2008).

Distribution and Habitat

Country distribution from AmphibiaWeb's database: Cote d'Ivoire, Ghana, Guinea, Liberia, Sierra Leone

	View distribution map in BerkeleyMapper.
	View Bd and Bsal data (2 records).

Cardioglossa occidentalis have been found in the rainforest zone in Ghana, the Ivory Coast, Liberia, Guinea and Sierra Leone. They can be found from lowland forests to 650 meters above sea level. They are more common in the western Ivory Coast and southeastern Guinea. Cardioglossa occidentalis prefer primary and some secondary rainforests close to flowing water. They prefer sandy soil and lots of leaf litter (Blackburn et al. 2008).

Life History, Abundance, Activity, and Special Behaviors
Cardioglossa occidentalis are wide spread in lower elevations of the rainforest, which is different from most species of Cardioglossa who prefer high elevations. They are associated with flowing water near sandy soil and heavy leaf litter. Males were located in the primary forest calling from within 2 m of the brooks that could maintain puddles even during the dry season. Male chorus sizes can average anywhere from 11 to 19 males with call occurring primarily at night. Males were heard calling at the end of the dry season and into the rainy season. Specifically, they called from February to November with most of the calling occurring during the core rainy season in September and October. Cardioglossa occidentalis breeds mostly in the wet season (Blackburn et al. 2008).

Cardioglossa occidentalis has a call very similar to close species of Cardioglossa, but is distinguishable from its slower pulse rate and different harmonics. The advertisement call is an isolated or series of loud, high whistles that can be heard at least 50 m away. The dominant frequency is 4.1 kHz but there are also two weaker harmonics at 2 and 6.2 kHz. The species also has a quieter “warble” call that can only be heard from 5 m (Blackburn et. al 2008).

A single captive female laid a clutch with 33 eggs that ranged in size from 2.5 – 2.8 mm in diameter without the gel capsule and 3.0 mm with the gel capsule. Oddly, tadpoles were recorded in ponds in the forest rather than in streams. Juveniles are recorded throughout the year (Blackburn et. al 2008).

Trends and Threats
As of March 2017, IUCN Red List has yet to assess the threats and trend status of Cardioglossa occidentalis. However, C. occidentalis was only split from Cardioglossa leucomystax in 2008, and the latter was assessed as “Least Concern” in 2004. The listing of "Least Concern" is due to its wide range of habitat tolerance and large population. Cardioglossa leucomystax population trend is decreasing, but not at a fast enough rate to be classified in a more threatened category. The only major threat to this species is the ongoing habitat loss. In order to protect this species, there are several conservation areas including the Virunga National Park and Korup National Park (Schiøtz et al. 2004).

Possible reasons for amphibian decline

General habitat alteration and loss
Habitat modification from deforestation, or logging related activities

Comments
The species authority is: Blackburn, D.C., Kosuch, J., Schmitz, A., Burger, M., Wagner, P., Gonwou, L.N., Hillers, A., Rodel, M.O. (2008). ''A New Species of Cardioglossa (Anura: Arthroleptidae) from the Upper Guinean Forests of West Africa.'' Copies, 3, 603-612.

Cardioglossa meanings “long-fingered” and occidentalis meanings “Westerly.” The common name for Cardioglossa occidentalis is the “Westerly Long-fingered Frog” (Blackburn et al. 2008).

The western population of C. leucomystax were renamed Cardioglossa occidentalis in 2008 based on a mitochondrial 16S ribosomal RNA sequence genetic divergence of 7.6 – 9.3% using maximum parsimony. Their likely next closest relatives are C. melanogaster and C. schioetzi (Blackburn et al. 2008).

References

Blackburn, D.C., Kosuch, J., Schmitz, A., Burger, M., Wagner, P., Gonwou, L.N., Hillers, A., Rodel, M.O. (2008). ''A New Species of Cardioglossa (Anura: Arthroleptidae) from the Upper Guinean Forests of West Africa.'' Copies, 3, 603-612.

Schiøtz, A., Amiet, J.L., Burger, M., Rödel M.O. (2004). Cardioglossa leucomystax. In: IUCN 2011. IUCN Red List of Threatened Species. Version 2011.2. www.iucnredlist.org. Downloaded on 01 May 2012.

Species Account Citation: AmphibiaWeb 2017 Cardioglossa occidentalis: Western Long-fingered Frog <https://amphibiaweb.org/species/7231> University of California, Berkeley, CA, USA. Accessed Dec 1, 2024.

Citation: AmphibiaWeb. 2024. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 1 Dec 2024.

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