NORTH-WESTERN JOURNAL OF ZOOLOGY 7 (2): 322-324 ©NwjZ, Oradea, Romania, 2011 Article No.: 111207 www.herp-or.uv.ro/nwjz

Rediscovered after ninety years: the Ethiopian high altitude dwarf species nana (Amphibia: )

Wolfgang BÖHME & Dennis RÖDDER

Zoologisches Forschungsmuseum Alexander Koenig, Adenauerallee 160, D-53113 Bonn, Germany. E-mail: [email protected]

Received: 12. January 2011 / Accepted: 28. April 2011 / Available online: 08.June 2011

Abstract. Herein we provide data on the rediscovery of Ptychadena nana from the Arussi Mountains in Ethio- pia. Furthermore, we discuss its taxonomic relationships to P. cf. nana from the Bale Mountains, which most likely represents a distinct species based on morphological differences. This is further supported by the fact that both mountain systems are separated by low altitudes.

Key words: Amphibia, Ptychadenidae: P. nana, P. sp. (n?), Ethiopia: Arussi Mts., Bale Mts.

Ptychadena nana Perret, 1980, the smallest of all de- The female (Fig. 1) was detected in material scribed Ptychadena species, is with certainty housed at the Zoologisches Forschungsmuseum known only from a series of 21 little col- Alexander Koenig (ZFMK), Bonn, where it is cata- lected in 1921 at Didda, Arussi Mountains, Ethio- logued as ZFMK 90143. Its label states that it was pia, at an altitude between 2000 and 3000 m a.s.l. found at 3800 m a.s.l. in the Begoji (or Bekoji) Mts. (Perret 1980, Largen 2001, Largen and Spawls which are also belonging to the Arussi Mountain 2010). In his 2001 paper, Largen still casted some system. The air distance to the known range of P. doubt on the specific distinctness of Perret's spe- nana according to Largen (2004) is approximately cies: "It is far from assured that this will remain 30 km (Fig. 2). It is a female with a head-body the case after collection of additional material and length of 29.7 mm and a tibia length of 12.5 mm, overlap in characters with those of P. neumanni its size being close to the maximum value known seems predictable". However, 10 years later, in a for females (30 mm) of this species, its tibia being book on the and reptiles of Ethiopia distinctly less than 50% of the head-body length (Largen and Spawls 2010), P. nana is still listed as a which is one of the characteristics for P. nana. The full species distinct from P. neumanni and charac- tibia-tarsus articulation reaches only the tympa- terized by its small size, reduced webbing, short num and fails to reach the eye as compared to the legs, and irregularly fragmented longitudinal dor- type material; moreover, the hind foot webbing sal skin ridges. (Fig. 1c) is reduced and corresponds perfectly with According to Largen and Spawls (2010), this the description and drawing given by Perret (1980: species is currently still only known from its type Fig. 8). Nearly no informative value derives from series collected in 1921 which was first assigned to the infraspecifically variable dorsal ridges which P. neumanni by Ahl (1924), until Perret (1980) sug- are very feebly expressed in this female, and its gested its specific distinctness. One of these thin middorsal yellow line (see Fig. 1a, b) is also a specimens was labelled with the locality Didda variable character (see Perret 1980) and therefore (ZMB 26878 H, see Perret 1980: Fig. 5 right) which likewise of no diagnostic value. However, the is either the village or the region (Didda Plateau: small size, the very short legs and the reduced at ca. 7°50'N and 40°16'E) within the Arussi Moun- webbing unequivocally fit the diagnostic features tains, and the others are assumed to originate from of P. nana and separate it from the similar but the same area. Until today, no definite data have slightly bigger P. neumanni which has also longer been available about altitudinal range, habitat, be- legs and a more extended webbing. haviour and colouration in life. The record of The altitudinal record of 3,800 m a.s.l. consid- Ptychadena nana from Goba, Bale Mts. (Schick erably exceeds the so far suggested altitudinal 2005), poses an allocation problem which is dealt range of P. nana which is given as between 2,000 with below. and 3,000 m a.s.l. (Perret 1980, Largen 2001, In regard of this poor state of knowledge, a Largen and Spawls 2010). Its habitat characterized new record of apparently true P. nana not far from by the collector as a "strohblumen" meadow is the the type locality seems to justify the present note. first indication of any habitat type populated by Rediscovered the Ethiopian high altitude dwarf species Ptychadena nana 323 this obviously rarely encountered little frog spe- of P. nana but show a dorsal ridge pattern like P. cies. neumanni. The ZFMK collection holds two likewise Largen (2001) examined two small Ptychadena small Ptychadena (ZFMK 82798-82799, a female from Ketama, deposited in the British Museum shown in Fig. 3 and a male, not shown) from the (Natural History), London, which fit the size range town of Goba (margin of Bale Mts. National Park,

Figure 1. Specimen of Ptychadena nana (ZFMK 90143) Figure 3. Specimen of Ptychadena cf. nana collected collected in the Begoji Mountains in lateral (A) and (ZFMK 82798) near Goba, Bale Mts. in lateral (A) dorsal view (B) as well as magnification of its hind and dorsal view (B) as well as magnification of its foot (C). hindfoot (C).

Figure 2. Map showing the general area of occurrence of Ptychadena nana and P. cf. nana in the Ethiopean Arussi Mountains and Bale Mts. The known range of P. nana according to IUCN data (Largen 2004) is indicated.

324 Böhme, W. & Rödder, D.

Figure 4. Ptychadena cf. nana (ZFMK 82798, A) and its habitat near Goba, Bale Mts. Fotos: S. Schick and S. Lötters.

07°01'N, 43°16'E) with head-body lengths of 32.1 Acknowledgements. We thank Mark-Oliver Rödel, Frank and 26.9 mm, respectively, and tibia lengths of Tillack and Michael Barej, Museum für Naturkunde Ber- only 14.1 and 12.5 mm, which makes their alloca- lin, for providing data on the holotype of P. nana. Susanne Schick and Stefan Lötters kindly made available photos of tion to P. neumanni unlikely, but with distinctly the small Ptychadena from Goba and its habitat and SL more extended webbing while the 4th toes are kindly commented on the manuscript. shorter than those in P. nana (compare Figs. 1c and 3c). This makes their allocation to P. nana uncer- tain. These frogs refer to the record of P. nana by Schick (2005) mentioned above, where even pho- References tographs of the habitat and one live individual Ahl, E. (1924): Über eine Froschsammlung aus Nordost-Afrika und have been published (Fig. 4). Arabien. Mitteilungen des Zoologischen Museums Berlin 11: 1- As a conclusion, Largen and Spawls (2010) are 12. Largen, M. (2001): Catalogue of the amphibians of Ethiopia, includ- apparently correct when stating that this group of ing a key for their identification. Tropical Zoology, Firenze 24: endemic Ethiopian highland Ptychadena, in which 307-402. except P. nana and P. neumanni are also involved Largen, M. (2004): Ptychadena nana. In: IUCN 2010. IUCN Red List of Threatened Species. Version 2010.4. www.iucnredlist.org, ac- P. erlangeri, P. largeni and an unidentified taxon, cessed at: 2011.01.07. will not be fully understood before more work Largen, M., Spawls, S. (2010): The amphibians and reptiles of will be done including acoustic and molecular Ethiopia and Eritrea. Ed. Chimaira, Frankfurt am Main. Perret, J.L. (1980): Sur quelques Ptychadena (Amphibia: Ranidae) studies. In any case, it seems to be useful to know d'Éthiopie. Monitore Zoologico Italiano, Firenze, n.s. Suppl.13: that the obviously rare representative of this 151-168. group, viz. P. nana, could be found again after 90 Schick, S (2005): Eine batrachologische Erkundungsreise in das äthiopische Hochland. Amphibia, Rheinbach 4: 31-34. years, and even at a much higher altitude than ex- pected.