Phrynobatrachus scheffleri

Phrynobatrachus scheffleri (Nieden, 1911)

Original Published Description:

Nieden, F. (1911).  Neue ostafrikanische Frösche aus dem Kgl. Zool. Museum in Berlin. Sitzungsberichte der Gesellschaft Naturforschender Freunde zu Berlin. 1910, 436-441.

Common Names

Scheffler's Puddle Frog (English)

Languages: English

Overview

Summary

Phrynobatrachus scheffleri is a small species (SVL < 20 mm) of puddle frog distributed in Kenya and Tanzania. Members of this genus are identified by the presence of a midtarsal tubercle, elongate inner metatarsal tubercle, and outer metatarsal tubercle. P. scheffleri is characterized by rudimentary webbing and lack of digital discs. Adult males exhibit greyish brown throats with minute asperities sparsely but evenly covering the dorsum and venter. In females, asperities are restricted to the peri-anal region.

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Distribution

It is widely distributed in semi-humid eastern Africa from coastal Kenya and Tanzania northwest up to the Ugandan border (Kakamega Forest). According to Channing & Howell (2006), this species may extend into Uganda. Specimens previously identified as P. scheffleri on the island of Zanzibar are most likely P. ungujae.

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Description

Diagnostic Description

Phrynobatrachus scheffleri is a small species (SVL < 20 mm) of puddle frog characterized by rudimentary webbing and lack of digital discs. Adult males exhibit greyish brown throats  and small femoral glands are present. Minute asperities sparsely but evenly cover the dorsum and venter in males; asperities are restricted to the peri-anal region in females.

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Size

Phrynobatrachus scheffleri is a miniature (snout–vent length < 20 mm) puddle frog species. Snout-vent length varies from 10-16.36 mm (n = 49) in males, and 13.0-19.11 mm ( n = 18) in females (Schick et al., 2010).

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Morphology

The body is slender with the head narrower than body. Maxillary teeth are present, and vomerine teeth are absent. Tongue is as long as wide, free for about two thirds of its length, tip is bifurcated, and a papilla is present. Nostrils are closer to tip of snout than to anterior corner of eye, and the canthus rostralis is slightly concave from tip of snout to nostril and straight from nostril to eye. The horizontal eye diameter is larger than the distance from nostril to anterior corner of eye, and the tympanum is invisible. Dorsal skin is finely coarse and ventrally smooth. Manual webbing is absent. Fingertips may be slightly swollen but not expanded to digital discs. Pedal webbing is rudimentary with 3-3.5 digits free of webbing on digit IV. Toe tips may be slightly swollen but not expanded to digital discs. Dorsum is brown with semi-regular dark brown markings on each side, and a light vertebral line may be present. The upper arm is of lighter colour, the back of thighs is banded. Venter is translucent to cream, with dark marks in the pectoral region. In males the throat is greyish brown, transverse gular folds are present, and small femoral glands are visible. Minute asperities sparsely but evenly covering the dorsum and venter in males, and asperities are restricted to the peri-anal region in females. The iris is golden brown. 

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Comparisons

Phrynobatrachus inexpectatus, P. mababiensis (including its junior synonyms P. vanrooyeni, P. chitialaensis, P. broomi), P. minutus, P. parvulus (including its junior synonyms P. schoutedeni, P. ukingensis nyikae) and the P. kakamikro are morphologically most similar to P. scheffleri. Toe webbing in P. inexpectatus is almost absent and the throat of males is strongly suffused with dark grey pigment (Largen, 2001). Phrynobatrachus minutus and P. parvulus males in breeding condition can be distinguished by throat colour, yellowish and dark grey, respectively (versus light grey in P. scheffleri). The following can be distinguished from P. scheffleri (< 20 mm SVL) by having larger adult SVL: Phrynobatrachus acridoides (ca. 25 mm), P. auritus (> 35 mm), P. bullans (ca. 25 mm), P. dendrobates (> 30 mm), P. irangi (> 50 mm ), P. kreffti (> 35 mm), P. natalensis (> 24 mm), P. pakenhami (> 25 mm) and P. versicolor (> 25 mm). Phrynobatrachus graueri, P. kinangopensis, P. perpalmatus, and P. rouxi are of similar SVL, but display digital discs and a visible tympanum (both absent in P. scheffleri). In addition, the foot of P. kinangopensis and P. perpalmatus is well webbed (versus rudimentary webbing in P. scheffleri). Phrynobatrachus pallidus, P. rungwensis, P. ukingensis, P. ungujae and P. uzungwensis share similar SVL with P. scheffleri and exhbit an indistinct tympanum, but differ through presence of well developed digital discs (versus absence in P. scheffleri). In addition, the throat is heavily pigmented in P. ukingensis, and P. uzungwensis exhibits extensive pedal webbing (vesus rudimentary webbing in P. scheffleri). Phrynobatrachus breviceps and P. stewartae exhibit more extensive pedal webbing (at maximum two and a half phalanges of fourth toe free of webbing versus three free of webbing in P. scheffleri).

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Ecology

Habitat and Ecology

It is associated with both open land (savanna or farm land) and secondary forest margins (Schick et al., 2010). It is found amongst herbaceous vegetation, leaf litter, rocks or mud at the swampy margins of lakes, rivers, streams and temporary pools in both moist grassland and forest clearings (Stuart and Cox, 2008).  According to Stuart and Cox (2008), it occurs up to at least 1,800m asl, while Schick et al. (2010) record that it only occurs up to 1,650 m asl.

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Population Biology

It is a poorly known species, and so there is little information on its abundance (Stuart and Cox, 2008).

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Associations

Other anurans calling at the Nairobi site included Phrynobatrachus natalensis, Amietophrynus maculates, Kassina senegalensis and Hyperolius glandicolor, while at Luisenga dam, Phlyctimantis keithae, Amietophrynus regularis, and Hyperolius pictus were heard calling (Schick et al., 2010).

Author(s): Zimkus, Breda Creative Commons: by-nc

Life History

Reproduction

It breeds in lake edges, rivers, streams and pools (Stuart and Cox, 2008).

Author(s): Zimkus, Breda Creative Commons: by-nc

Advertisement Call

Advertisement calls were recorded outside Nairobi, Kenya, and at Luisenga dam, Mufindi highlands, Tanzania by Schick et al. (2010). At the former site, calling and non-calling frogs were sitting on floating vegetation and at the edge of ponds or freely floating in small water bodies. Advertisement calls from both sites largely coincide and can be described as a long ‘trill’ consisting of a single note. Pickersgill (2007) described and illustrated an advertisement call for P. scheffleri from Bermi, Tanzania (1900 m above sea level), which appears to belong to a population conspecific to the Nairobi and Luisenga dam populations. Phrynobatrachus mababiensis, P. parvulus and P. kakamikro produce advertisement calls of more than one note and have lower pulse rate and higher dominant frequency.

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Behaviour

Activity and Special Behaviors

This species is nocturnal (Schick et al., 2010).

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Evolution and Systematics

Phylogenetics

Mitochodrial sequence data from 12S rRNA, valine-tRNA, and 16S rRNA fragment, as well as combined sequence data from mitochondrial and nuclear (RAG-1) genes indicate that P. inexpectatus and P. minutus are the sister clade to P. scheffleri (Zimkus et al., 2010). These species fall within a larger group of puddle frogs that are endemic to East African montane regions and also includes P. keniensis, P. kakamikro, P. mababiensis (C), and P. parvulus, P. rungwensis, and P. uzungwensis (Zimkus et al., 2010).

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Conservation

IUCN Red List Category

Least Concern

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Justification of Conservation Status

Even though this species is considered somewhat poorly known, the IUCN Red List (2009) categorizes it as Least Concern given its relatively wide distribution, presumed large population, and apparent adaptability to habitat change (i.e. occurrence in farm land). The assessment notes that it is unlikely to be declining fast enough to qualify for listing in a more threatened category.

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Threats

It is likely to be impacted by habitat degradation, especially as a result of agricultural expansion, human settlement and overgrazing by livestock (Stuart and Cox, 2008).

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Taxonomy

  • Phrynobatrachus scheffleri — Largen, 2001 (synonym)
  • Pseudarthroleptis scheffleri — Deckert, 1938 (synonym)
  • Arthroleptis scheffleri Nieden, 1911 "1910" (synonym)

References

Channing, A., & Howell K. (2006).  Amphibians of East Africa. Comstock books in herpetology. 418 p., [24] p. of plates.
Harper, E. B., Measey G. J., Patrick D. A., Menegon M., & Vonesh J. R. (2010).  Field Guide to Amphibians of the Eastern Arc Mountains and Coastal Forests of Tanzania and Kenya. 320.
 
Pickersgill, M. (2007).  Frog search: results of expeditions to southern and eastern Africa from 1993-1999. 574 p.
Schick, S., Zimkus B. M., Channing A., Koehler J., & Lötters S. (2010).  Systematics of 'Little Brown Frogs' from East Africa: Recognition of Phrynobatrachus scheffleri and description of a new species from the Kakamega Forest, Kenya (Anura: Phrynobatrachidae). Salamandra. 46(1), 24-36.
Stuart, S. N., & Cox N. A. (2008).  Phrynobatrachus scheffleri. In: IUCN 2010. IUCN Red List of Threatened Species. Version 2010.1. <www.iucnredlist.org>.
Zimkus, B. M., & Schick S. (2010).  Light at the end of the tunnel: insights into the molecular systematics of East African puddle frogs (Anura: Phrynobatrachidae). Systematics and Biodiversity. 8(1), 39-47.
Zimkus, B. M., Rödel M-O., & Hillers A. (2010).  Complex patterns of speciation and diversity among African frogs (genus Phrynobatrachus). Molecular Phylogenetics & Evolution. 55, 883-900.