AmphibiaWeb - Arthroleptis perreti
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(Translations may not be accurate.)

Arthroleptis perreti Blackburn, Gonwouo, Ernst & Rödel, 2009
Perret’s Squeaker Frog
family: Arthroleptidae
genus: Arthroleptis
Species Description: Blackburn DC, Gonwouo LN, Ernst R, Roedel MO. 2009. A new squeaker frog (Arthroleptidae: Arthroleptis) from the Cameroon volcanic line with redescriptions of Arthroleptis adolfifriederici Nieden, 1911 (1910) and A. variabilis Matschie, 1893. Breviora 515: 1-22.

© 2010 David C. Blackburn (1 of 2)
Conservation Status (definitions)
IUCN Red List Status Account Endangered (EN)
CITES No CITES Listing
National Status None
Regional Status None

   

 

View distribution map in BerkeleyMapper.
View Bd and Bsal data (8 records).

Description
Arthroleptis perreti is a moderately robust leaf litter frog with a maximum snout-vent length of 44.7 mm, a mean male snout-vent length of 29.5 mm, and a mean female snout-vent length of of 37.5 mm. The head is somewhat broad, and the head length is 79% head width. The snout projects approximately 1 mm beyond the lower jaw. The rostral tip is rounded in dorsal view, blunt and only slightly curving posteroventrally in lateral view. The naris are small, rounded, facing laterally, and barely visible in dorsal view. The internarial region is flat; with a 90% interorbital distance. The canthus rostralis is short, indistinct, rounded. The loreal region weakly concave. The eyes are in the medial position, barely projecting beyond the eyelids in dorsal view and not projecting laterally beyond the margins of head. The eyes are flush with dorsal margin of head in lateral view with its diameter approximately equal to interorbital distance. It has a round pupil, which is slightly horizontally elliptical in preservative. The eye diameter is 1.5 times of the eye–narial distance and 2.1 times the distant from naris to rostral tip. The tympanum is distinctly ovoid, with the height slightly less than half the diameter of eye. The tympanic annulus poorly defined; the supratympanic fold absent. The tongue is very broad, heart-shaped, covered with many small pustules. The anterior attachment of tongue is narrow with its posterior notch approximately one fourth anteroposterior length of tongue. There is a prominent, flat, flap-like median papilla on dorsal tongue surface near anterior attachment. The choana is hidden by maxillary shelf in ventral view; premaxillary and maxillary teeth are present, but hidden by the lips; vomerine teeth absent. The skin of limbs, dorsal surface of head and body, and ventral head are smooth when preserved and present as tuberculate in live specimens. The skin of the lateral body is glandular, becoming more indistinct on the ventral surface; a median skin raphe is prominent in live specimens but very indistinct when preserved. The cloacal region is weakly glandular. It possesses well developed slender limbs and digits. The digits of both manus and pes are also slender. The palmar and metacarpal tubercles are present but weakly developed and barely projecting from surface of hand. The relative length of fingers is: III > IV > II ≥ I. All fingertips are rounded and slightly swollen having an approximate width as the rest of fingers. The finger have rounded, prominent, globular, single subarticular tubercles. Webbing between manual digits is absent. The thigh length is 93% of crus length. There is a prominent flange-like inner metatarsal tubercle with a length 72% of first toe length. The relative length of toes is: IV > III > V > II > I. The toe tips are pointed and slightly expanded to approximately same width as interphalangeal regions. The toes have prominent, single, elongate, and slightly conical subarticular tubercles. Webbing between pedal digits is absent (Blackburn et al. 2009).

Arthroleptis perreti has a moderately larger body size, and was previously identified as A. adolfifriederici but has been long recognized as distinct (Perret 1966). The species is very similar to A. variabilis but is readily distinguished from the later by lacking a midline gular stripe and by having a relatively longer snout. In females, The fourth finger is longer than the first and second fingers. The posterior surface of the thigh of A. perreti is dark gray with many small white spots that are absent in A. variabilis, which exhibits poorly defined light mottling on a dark-brown or -gray background. With a maximum body size of 44.7 mm snout-vent length, A. perreti appears as the largest described Cameroonian Arthroleptis, including A. variabilis (37.8 mm snout-vent length; Blackburn 2008a). The mean male snout-vent length of A. perreti is 29.5 mm, whereas the mean female snout-vent length is 37.5 mm. Arthroleptis perreti is differentiated from other medium to large Arthroleptis as follows: From A. adolfifriederici by less granular skin, more extensive pigmentation on throat, and less on the globular inner metatarsal tubercle; from A. affinis by lacking supernumerary tubercles on the feet. It differs from A. francei and A. stenodactylus by having a tibiofibula length greater than 50% snout-vent length; from A. krokosua by the presence of lighter pigmentation on throat and vent and lacking large well-defined black spots on the lateral surface of the body including a fourth finger longer than the first and second fingers. It can be further distinguished from A. stenodactylus by an inner metatarsal tubercle length less than 80% of first toe length. It differs from A. nikeae by having a much smaller adult body size (50 mm snout-vent length in A. nikeae) and from A. tanneri by a relatively narrower head. It differs from A. variabilis by lacking the prominent white gular stripe on the midline of throat; and from both A. stenodactylus and A. variabilis by having a relatively smaller and more globose inner metatarsal tubercle (Blackburn et al. 2009).

Based on field notes and photographs on live specimens, the dorsal coloration ranges from dark gray with brown markings (MCZ A-137980) to brown with red tones (MCZ A-137978). There are darker markings on the dorsal and lateral surfaces ranging from light to dark brown and even black. Lighter markings are present on lateral surface ranging from white to gray. The ventral surface of throat is generally gray with faint creamy yellow tones; the venter with more pronounced creamy yellow tones; bright yellow splotches in the inguinal region (Blackburn et al. 2009).

When preserved in alcohol, A. perreti harbors a color silvery brown dorsal ground with small, weakly defined gray and well-defined dark brown spots. The iris appears dark brown with pale cream pupil. The snout is silvery gray to dark brown near the rostral tip. The loreal and suborbital regions are nearly solid medium to dark brown becoming lighter and slightly broken behind to eye. The interorbital bar is medium brown but broken and poorly delimited from other brown spots on posterodorsal surface of head. The supratympanic band is dark-brown and extends from the posterodorsal margin of the orbit, slightly continuous with dark mask of suborbital region, extending posteroventrally and terminating anterior to and just dorsal of the arm. The tympanum is translucent, with silver flecks, and darkened dorsally becoming confluent with supratympanic band. The lateral margin of the lower jaw is dark brown with small white spots at regular intervals. The throat is brown with distinct white spots on the posterior throat, just anterior to clavicles and laterally bordering the omosternum, darker than rest of throat. The dorsal surface of arms are silvery gray grading into dark brown on forearm and wrist. One can see single, broken dark-brown band on forearm. The dorsal surface of hands mottled gray and brown with large cream-colored spots on second and first fingers. The interphalangeal joint of all fingers is unpigmented and cream in color. At the posterior end to the skull, there are two dark-brown, highly broken chevrons with apices directed anteriorly, separated by a light gray-brown region approximately 3.8 mm in anteroposterior length. There are highly broken, dark-brown band at the lateral margin of dorsum extending from just above arm along lateral surface toward inguinal region before becoming indistinct. The lateral surface of body has many small medium- and dark-brown spots and the base color is much lighter than the dorsum, grading into creamy white on the ventral surface. The dorsal surface of the hind limbs are grayish brown and very a indistinct, broken, dark-brown band is present on dorsal surface of the thigh. The posterior surface of the thigh is dark brown with prominent large white spots. Present on crus are two prominent transverse dark-brown stripes. The feet are mottled gray and brown with poorly defined medium-brown spot on lateral margin of foot at base of metatarsal V. The base color of dorsal foot is silvery and creamy with many small brown well-defined melanocytes. The general trend is of lighter and less pigmentation from lateral to medial toes while dorsal surface of toe tips are dark brown and the ultimate phalangeal joints of toes I – III are unpigmented and creamy while the ultimate phalangeal joints of toes IV – V are lighter in pigmentation than surrounding skin. A dark-brown triangle with apex directed dorsally centered on cloaca. The medial surfaces of arm and forearm are unpigmented and creamy. Ventral surface of forearm very dark brown with several prominent white spots while ventral surface of hand and fingers brown. The palmar, metacarpal, and subarticular tubercles are unpigmented. The ventral fingertips lighter in color than rest of finger. The brown pigmentation of throat broken into mottling over pectoral girdle extending ventrally as diffuse brown pigmentation with large, poorly defined white spots. The venter and ventral thigh are both cream colored with few scattered brown melanocytes. The ventral surface of the crus is mottled brown and cream while the plantar surface is homogeneous dark brown. The subarticular tubercles on toes and inner metatarsal tubercle is lighter brown, tending to gray, than the surrounding skin, but not unpigmented (Blackburn et al. 2009).

In A. perreti, the median papilla of the tongue can be more conical. Sexual dimorphism in this species is similar to that of other species of Arthroleptis (Blackburn 2009) and includes larger body size in females, the presence of an elongated third finger, and both digital and inguinal spines in males. Small spines line the medial surface of both the second and third fingers in males and varies from one individual to the other. In some larger males, pronounced white spines are found in the inguinal region and extend both forward along the lateral surface of the body and dorsally onto the posterior dorsal surface of the body and the proximal dorsal surface of the hind limbs. Unlike females, the fourth finger of male A. perreti is similar in length to that of the first and second fingers (Blackburn et al. 2009)

Distribution and Habitat

Country distribution from AmphibiaWeb's database: Cameroon

 

View distribution map in BerkeleyMapper.
View Bd and Bsal data (8 records).
Arthroleptis perreti is known from Mt. Manengouba, the third inland peak from the coast along the Cameroon volcanic line in south western Cameroon. It is a high elevation leaf litter frog found in elevations from 1,400 - 2,200 m. Although presently only documented from the latter site, they might also occur on several other nearby mountains, including Mt. Nlonako, Mt. Kupe, and in the Rumphi Hills where A. adolfifriederici has previously been documented. Even if present at these localities, A. perreti would still have an extent of occurrence less than 20,000 km2 (Blackburn et al. 2009).

Life History, Abundance, Activity, and Special Behaviors
They are known to be active in primary and degraded montane forest floor in moist leaf litter during the day from 1000 – 1400 h and late in the afternoon from 1600 – 1800 h during sunny days (Gonwouo pers observation).

The advertisement calls are known to be fast series of high-pitched ‘kick’ pulses (Channing and Rödel 2019).

As most other species from the genus Arthroleptis not much is known about its reproductive behavior but, it should breed by direct development.

Larva
As most other species from the genus Arthroleptis not much is known about its reproductive behavior but, it should breed by direct development.

Trends and Threats
Arthroleptis perreti is categorized by the IUCN Red List Status Account as “Endangered” given its restricted range towards the summit of Mt Mannegouba. It was formerly known to be abundant and common species around its range but has been experiencing declines over recent years due to habitat loss and degradation. The detection of Batrachochytrium dendrobatidis on Mt manengouba is also likely contributing to population decline over recent years (Hirschfeld et al. 2016). This mountain is a hotspot of amphibian diversity within sub-Saharan Africa and was upgraded as a Herpeto-Ornithological sanctuary in 2023 and as such the species could benefit from protection measures being implemented at the site (Gonwouo et al. unpublish data).

Possible reasons for amphibian decline

General habitat alteration and loss
Habitat modification from deforestation, or logging related activities
Intensified agriculture or grazing
Disease

Comments
Arthroleptis perreti was described as a unique species based on morphology (Blackburn et al. 2009).

This species is named in honor of Dr. Jean-Luc Perret who provided preliminary, but accurate, comments on this new species more than 40 years ago (see Perret 1966) arguing that A. perreti is distinct from A. adolfifriederici known from the Eastern Arc Mountains.

The Cameroon Volcanic Line is an important center of diversity within Cameroon, especially of amphibians with most species concentrated around Mt. Manengouba. The description of A. perreti and other restricted range species from other taxonomic groups enhanced the development of conservation measures to preserve the unique biodiversity found on this mountain.

References
Blackburn D.C., Gonwouo L.N., Ernst R., Rödel M.O. (2009). A new squeaker frog (Arthroleptidae: Arthroleptis) from the Cameroon volcanic line with redescriptions of Arthroleptis adolfifriederici Nieden, 1911 (1910) and A. variabilis Matschie, 1893. Breviora 515(1), 1-22. [link]

Blackburn, D.C. (2009). Diversity and evolution of male secondary sexual characters in African squeakers and longfingered frogs. Biological Journal of the Linnean Society 96(3), 553–573. [link]

Hirschfeld, M., Blackburn D.C., Doherty-Bone T.M., Gonwouo L.N., Ghose S., Rödel M.-O. (2016). Dramatic declines of montane frogs in a Central African biodiversity hotspot. PLoS One 11(5), e0155129. [link]

Channing, A., Rödel, M.-O. (2019). Field Guide to the Frogs and other Amphibians of Africa. Cape Town, South Africa, Struik Nature.

Perret, J.-L. (1966). Les amphibiens du Cameroun. Zoologische Jahrbucher (Systematik), 8, 289–464.



Originally submitted by: Gonwouo Nono LeGrand (2024-01-26)
Description by: Gonwouo Nono LeGrand (updated 2024-01-26)
Distribution by: Gonwouo Nono LeGrand (updated 2024-01-26)
Life history by: Gonwouo Nono LeGrand (updated 2024-01-26)
Larva by: Gonwouo Nono LeGrand (updated 2024-01-26)
Trends and threats by: Gonwouo Nono LeGrand (updated 2024-01-26)
Comments by: Gonwouo Nono LeGrand, Ann T. Chang (updated 2024-01-26)

Edited by: Ann T. Chang (2024-01-26)

Species Account Citation: AmphibiaWeb 2024 Arthroleptis perreti: Perret’s Squeaker Frog <https://amphibiaweb.org/species/7253> University of California, Berkeley, CA, USA. Accessed Apr 20, 2024.



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Citation: AmphibiaWeb. 2024. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 20 Apr 2024.

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