AMPHIBIAWEB
Conraua beccarii
family: Conrauidae
Conservation Status (definitions)
IUCN (Red List) Status Least Concern (LC)
CITES
Other International Status None
National Status None
Regional Status None

Country distribution from AmphibiaWeb's database: Ethiopia

 

View distribution map using BerkeleyMapper.

   

From the Encyclopedia of Life account:

Etymology

This species is named after Signor Nello Beccari, who discovered it (Boulenger 1911).


Author: Goldsmith, Willy
License: http://creativecommons.org/licenses/by-nc/3.0/

Taxonomic Notes

This species was originally described as Rana beccarii (Boulenger 1911).


Author: Dietterich, Lee
License: http://creativecommons.org/licenses/by-nc/3.0/

Summary

Conraua beccarii is a large and highly aquatic species of frog found in the highlands of Ethiopia and Eritrea. Its dorsum is blackish or purplish brown, and its venter is whitish, spotted or marbled with brown on the flanks and throat. A broad fold is present along the outer edge of the fifth toe, and the subarticular tubercles are well developed. Another prominent fold is present across the interorbital region and behind the eyes, where it splits and extends down most of the length of the flanks. Males are particularly distinctive in appearance due to an enormous widening of the head, as well as two globular masses of muscle separated longitudinally on top of the head.


Author: Goldsmith, Willy
License: http://creativecommons.org/licenses/by-nc/3.0/

Distribution

This species occurs in northern and western Ethiopia, extending into southern Eritrea, in highlands west of the Rift Valley (Largen 2004). It has been documented from montane grasslands near both Asmara and Addis Ababa, and it appears to be common in forests at lower elevations near the towns of Jimma and Bonga in western Ethiopia (Largen and Spawls 2010).


Author: Goldsmith, Willy
License: http://creativecommons.org/licenses/by-nc/3.0/

Osteology

Clarke (1981) gives a thorough comparative analysis of many osteological characters between Conraua and several other African ranine frog genera, including several characters in which C. beccarii differs from the other members of its genus. In particular, in this species, the zygomatic ramus is “much longer than [the] otic ramus, curving down towards the maxilla but not articulating with it; [with] the distal end of the zygomatic ramus curving upward, away from the maxilla” (Clarke 1981). This character appears to be unique to Conraua beccarii and therefore represent an autapomorphy. The pterygoid process of the maxilla is “moderately developed, and slightly overlapping or abutting [the] anterior ramus of [the] pterygoid” (Clarke 1981), unlike the other Conraua species, which lack the pterygoid process of the maxilla entirely. Finally, the terminal phalanges of the fingers are “simple [and] knob-like” distally, with the toes slightly T-shaped, and “the anterior distal border of the phalanx perpendicular to the axis” with no median notch (Clarke 1981).


Author: Goldsmith, Willy
License: http://creativecommons.org/licenses/by-nc/3.0/

Morphology

Vomerine teeth appear to be absent from most specimens of Conraua beccarii (Scortecci 1931, Spanò 1971), although Boulenger (1911) found that they may be very subtly present in two groups just behind the level of the small choanae. The head is substantially depressed and may be 2.5-3.0 times wider than it is long, and the snout is broadly rounded. The canthus rostralis is indistinct, the loreal region is grooved, and the distance from the nostrils to the orbits is slightly less than or equal to the distance from the nostrils to the tip of the snout. The eyes are supero-lateral, and the interorbital space is as broad as or slightly broader than the upper eyelid. The tympanum is hidden externally (Boulenger 1911, Scortecci 1931, Spanò 1971).

The fingers are moderately long, with slightly swollen tips and a distinct narrow dermal margin on the first and fifth fingers. The subarticular tubercles are well developed. The first finger is shorter than the second, and the fourth finger is slightly shorter than the third. The tibio-tarsal articulation reaches the commissure of the mouth in females, and extends to the posterior margin of the eye in males and juveniles. The tibia is contained 2.25-2.33 times in the snout-vent length. The toes are rather short, fully webbed, and terminate in rather large rounded disks embraced by the webbing. A broad fold is present along the outer edge of the fifth toe, and the subarticular tubercles are well developed and quite prominent. An elongate, blunt inner metatarsal tubercle is present and measures 2/5 to 2/3 of the length of the inner toe. A narrow tarsal fold is present.

The skin may be smooth or bear small, flat warts dorsally. A strong fold traverses the interorbital region, passes behind the eyes, and extends on each side to the point of insertion of the hindlimb. Coloration in this species is blackish or purplish brown dorsally, off-white ventrally, and with grayish brown spots or marbling on the flanks, throat, and chest. Juveniles may be lighter shades of yellowish gray or grayish brown dorsally, with darker streaking or mottling on the back and dark transversal bars on the limbs (Boulenger 1911, Largen and Spawls 2010). While males of this species have no vocal sacs, they are larger than females, and may have grayish nuptial pads on the dorsal surface of the four fingers (Boulenger 1911, Spanò 1971), although these may be lacking in some specimens (Scortecci 1931). Other sexual dimorphisms in this species include that the heads of males are strikingly wide, and the muscles on top of the head are so enlarged as to take the form of two globular masses separated longitudinally by a profound depression. These traits are either absent or weakly expressed in females. Furthermore, in males, but not in females, the width of the head is always more than half of the snout-vent length, and the interorbital space is always wider than the upper eyelid.


Author: Goldsmith, Willy
License: http://creativecommons.org/licenses/by-nc/3.0/

Size

According to Largen and Spawls (2010), the largest recorded specimen of Conraua beccarii measured 155 mm. The snout-vent length (SVL) of the holotype is 103 mm (Boulenger 1911).

Scortecci (1931) examined three adults of either sex. The males measured 140-153 mm in SVL, with the head 80-88 mm wide, the length from the snout to the tip of the fourth toe 320-340 mm, the forelimb 94-100 mm long, the hindlimb 195-214 mm long, the nostril slightly closer to the orbit (9-10 mm) than to the tip of the snout (10-11 mm), the upper eyelid 10-11 mm wide, and the interorbital space 13-15 mm wide. The females measured 110-124 mm in SVL, with the head 54-59 mm wide, the length from the snout to the tip of the fourth toe 235-280 mm, the forelimb 63-78 mm long, the hindlimb 135-166 mm long, the nostril slightly closer to the orbit (6-7 mm) than to the tip of the snout (7-8 mm), the upper eyelid 7-9 mm wide, and the interorbital space 8.5-9.0 mm wide (Scortecci 1931).

Spanò (1971) made a similar series of measurements on three additional male specimens. These specimens measured 135-162 mm in SVL, with the head 76.0-90.5 mm wide, the length from the snout to the tip of the fourth toe 305.0-346.5 mm, the forelimb 87.5-99.0 mm long, the hindlimb 184-211 mm long, the nostril slightly closer to the orbit (9.0-9.2 mm) than to the tip of the snout (10.0-11.2 mm), the upper eyelid 10.3-11.1 mm wide, and the interorbital space 13.2-15.7 mm wide. Both Scortecci (1931) and Spanò (1971) both found the SVL to be 1.6-1.8 times the maximum width of the head in this species.


Author: Goldsmith, Willy
License: http://creativecommons.org/licenses/by-nc/3.0/

Diagnostic Description

This species is very large and, while it is not exclusively aquatic, it tends to stay very close to rivers, streams, and occasionally the large pools associated with them. Its most distinctive feature is its large head, the width of which commonly exceeds half of the snout-vent length, and which is marked with two prominent muscular bumps, one on either side, separated by a distinct groove. Adult coloration is very dark with indistinct mottling that may include hues of black, purple, or brown; the underside of the frog is lighter but may be heavily mottled with gray or brown, especially anteriorly and laterally. Juveniles may be lighter dorsally and have distinct dark crossbars on the limbs. The tympanum is not visible externally, and the toes are fully webbed with distinct terminal discs (Boulenger 1911, Scortecci 1931, Spanò 1971, Largen and Spawls 2010).


Author: Dietterich, Lee
License: http://creativecommons.org/licenses/by-nc/3.0/

Habitat and Ecology

This species is highly but not exclusively aquatic, and it is most commonly found in or near rivers, streams, and large pools. Individuals tend to dive into deep water when startled, and while this species appears to prefer montane grasslands and forests at altitudes of 800-2500 m asl, it can also be found in forests at lower elevations (Largen 2004, Largen and Spawls 2010).


Author: Goldsmith, Willy
License: http://creativecommons.org/licenses/by-nc/3.0/

Population Biology

Conraua beccarii appears to be abundant in several localities in Ethiopia, but its population demographics remain poorly understood, in part because it is very difficult to catch (Largen 2004).


Author: Goldsmith, Willy
License: http://creativecommons.org/licenses/by-nc/3.0/

Activity and Special Behaviors

Conraua beccarii is primarily nocturnal, although it may be active during the day if disturbed from the rocks and plant matter (usually very close to a river or other source of deep water) on which it commonly rests during the day. Unlike Xenopus, this species can rarely be caught by dredging with a net (Largen and Spawls 2010).


Author: Goldsmith, Willy
License: http://creativecommons.org/licenses/by-nc/3.0/

Reproduction

Spanò (1971) recorded the collection of some clusters of Conraua beccarii eggs in late August at the end of the rainy season. The eggs measured 6-7 mm in diameter, or 3.2-3.4 mm less the jelly coat, and the embryos appeared to be in the first stages of development (Spanò 1971). Otherwise, the breeding behavior and larval biology of this species remain unknown (Largen and Spawls 2010), although the lifestyle and habitat of adults of this species suggests that the larvae are likely aquatic.


Author: Goldsmith, Willy
License: http://creativecommons.org/licenses/by-nc/3.0/

IUCN Red List Category and Justification of Conservation Status

The IUCN Red List (2010) categorizes this species as Least Concern “in view of its relatively wide distribution, presumed large population, and because it is unlikely to be declining fast enough to qualify for listing in a more threatened category” (Largen 2004).


Author: Goldsmith, Willy
License: http://creativecommons.org/licenses/by-nc/3.0/

Trends

Populations of this species are decreasing (Largen 2004).


Author: Goldsmith, Willy
License: http://creativecommons.org/licenses/by-nc/3.0/

Threats

While this species as a whole is not threatened, factors such as the encroachment and degradation of its habitat by expanding human settlements, the consequent increased demand for natural resources, and water pollution may threaten local populations of this species (Largen 2004).


Author: Goldsmith, Willy
License: http://creativecommons.org/licenses/by-nc/3.0/

Conservation Actions and Management

This species has not been documented from any protected areas (Largen 2004).


Author: Goldsmith, Willy
License: http://creativecommons.org/licenses/by-nc/3.0/