Phrynobatrachus auritus Boulenger, 1900
Original Published Description:
Eared River Frog (English), Golden Puddle Frog (English)
Phrynobatrachus auritus is a medium to large sized species (SVL < 35 mm) of puddle frog with a wide distribution across Central Africa. Members of this genus are identified by the presence of a midtarsal tubercle, elongate inner metatarsal tubercle, and outer metatarsal tubercle. This species characterized by a distinct tympanum, moderate to extensive pedal webbing, and large discs on the fingers and toes. A pair of narrow glandular folds is normally present that begin behind the eyes, converge in the scapular region, and continue down the back to the sacral region.
This species ranges from southeastern Nigeria and southern Cameroon, east to eastern Democratic Republic of Congo, western Uganda and Rwanda. It is presumed to occur in the Cabinda Enclave of Angola. There is an absence of records through much of the Congo Basin, but this is probably due to under-sampling (Amiet et al., 2004).
Country records: Cameroon, Central African Republic, Congo, Democratic Republic of the Congo, Equatorial Guinea (including Bioko Island), Gabon, Nigeria, Rwanda, Uganda
This species name is from the Latin 'auritus,' meaning eared.
It is possible that the eastern populations of this species should be separated as P. discodactylus (Amiet et al., 2004). Lamotte and Xavier (1966) observed that some species previously recognized as this species exhibit more extensive webbing (up the disk on the inner surface of the second toe), greater pigmentation of the throat and breast in females, and males are slightly smaller size (males below 25 mm).
Phrynobatrachus auritus is a medium to large sized species (SVL < 35 mm) characterized by a distinct tympanum, moderate to extensive pedal webbing (1-2 phalanges free of webbing on toe IV), and large discs on the fingers and toes. A pair of narrow glandular folds is normally present that begin behind the eyes, converge in the scapular region, and continue down the back to the sacral region.
Lamotte and Xavier (1966) report that males (27 to 29 mm) are much smaller than females (32 to 35 mm). Males of eastern populations of this species, formerly P. discodactylus are slightly smaller, measuring below 25 mm. The SVL reported in the type description is 37 mm (Boulenger, 1900).
Aspect is raniform with a slender habit and long, robust hind legs. A conical papilla is present in the middle of tongue. Head is moderate, as long as broad. Snout is pointed, projecting beyond the mouth. Canthus rostralis is angular, and loreal region is nearly vertical. Nostril is equidistant from the eye and the tip of the snout. The interorbital space is narrower than the upper eyelid. The tympanum is distinct, measuring nearly half the diameter of the eye. The first finger is as long as the second. Subarticular tubercles are small. The fingers and toes are dilated into large disks with well-defined circummarginal grooves. Toes are two-thirds webbed. According to Lamotte and Xavier (1966), 2 phalanges are free of webbing on toe IV, although a fringe is present. Zimkus (unpublished) found that specimens had more extensive webbing with only 1 phalange free of webbing. Tips of fingers and toes are dilated into small discs. An ovular inner metatarsal tubercle, and small, round outer metatarsal tubercle are present. A small, round midtarsal tubercle is also present behind the inner metatarsal tubercle. The tibio-tarsal articulation reaches the tip of the snout. The dorsal skin smooth with very small warts. A pair of narrow glandular folds is normally present that begin behind the eyes, converge in the scapular region, and continue down the back to the sacral region. These glandular cords may or may not meet and can be shorter in length or more rarely, absent. A similar supratympanic fold is present, traveling from the eye to the shoulder. In males, there are a number of longitudinal vocal folds, indicating the presence of a single median vocal sac, with many whitish asperities. A nuptial pad is present on the dorsum and inner side of manual digit I. No femoral gland is visible.
Dorsum is greyish or reddish brown, darker in the middle of the back. The top of the head and the area between the glandular portions are sometimes lighter. In some specimens, the top of the head and shoulder region is tan in color, while the rest of the body is mottled in brown. A thin, light vertebral line may be present, which is continued along the middle of the upper surface of the thigh and the inner side of the leg. Glandular folds are edged with a dark to black color. A few round black spots may be present on the pelvic region. Limbs exhibit rather indistinct barring. Outer sides of thighs are blackish brown, edged with whitish near the vent. Inner sides of legs are also blackish brown. Venter is white. Small brownish spots are present on the throat and breast in the female. The throat is blackish in males. Males have an internal subgular vocal sac.
Phrynobatrachus plicatus most resembles P. auritus, but it can be distinguished by its slightly larger size (males 36 mm; females 40 mm), indistinct tympanum, less webbing (up to 3 phalanges free on digit IV), and increased pigmention on the ventral side.
Habitat and Ecology
It lives on the floor of primary, secondary and riparian rainforest, and is often associated with rivers. It is not found in open habitats outside forest (Amiet et al., 2004). It reaches submontane elevations on Bioko Island (up to 1200–1300 m) but is present only at lowland elevations (up to 900 m) on mainland Cameroon (Zimkus, 2009).
It is a common species (Amiet et al., 2004).
Populations of this species are decreasing (Amiet et al., 2004).
Males could occasionally be heard calling in chorus with Bufo gracilipes (Márquez, 2000).
This species breeds in small pools (Amiet et al., 2004).
Márquez (2000) reported on the call of populations from Equatorial Guinea. Males called from the ground or rocks located at the edges of ponds or calm streams and sometimes from the water. Often larges choruses were formed. They generally called at night but could be heard during the day, especially in the morning. The call itself is composed of a sequence of 15-20 pulses emitted at regular intervals with 58-62 pulses/second. A racous trill is formed with a mean dominant frequency of 1622 Hz.
Evolution and Systematics
Sequence data from mitochondrial 12S rRNA, valine-tRNA, and 16S rRNA , as well as combined sequence data from mitochondrial and nuclear (RAG-1) genes support a sister relationship between P. auritus and P. plicatus (ZImkus et al, 2010).
IUCN Red List Category and Justification of Conservation Status
The IUCN Red List (2009) categorizes this species as Least Concern in view of its wide distribution, tolerance of a degree of habitat modification, presumed large population, and because it is unlikely to be declining fast enough to qualify for listing in a more threatened category (Amiet et al., 2004).
It is presumably adversely affected by the loss of forest habitat for agriculture, logging and human settlements (Amiet et al., 2004).
Conservation Actions and Management
It occurs in a number of protected areas within its large range (Amiet et al., 2004).
- Phrynobatrachus discodactylus Boulenger, 1919 (synonym)
- Phrynobatrachus plicatus auritus — Perret, 1966 (synonym)
- Phrynobatrachus auritus — Lamotte and Xavier, 1966 (synonym)