Ptychadena neumanni (Ahl, 1924)

Goutte, Sandra, Reyes-Velasco *, Jacobo, Freilich, Xenia, Kassie, Abeje & Boissinot, Stephane, 2021, Taxonomic revision of grass frogs (Ptychadenidae, Ptychadena) endemic to the Ethiopian highlands, ZooKeys 1016, pp. 77-141 : 77

Ptychadena neumanni (Ahl, 1924)

Rana neumanni Ahl, 1924: 4.

Ptychadena neumanni - Perret 1980: 157.

Rana (Ptychadena) neumanni - Dubois 1981: 233.

Ptychadena (Ptychadena) neumanni - Dubois 1992: 316.

Lectotype by present designation.

One adult male (ZMB26879-1) collected on 2 February 1901 by Oscar Neumann in Gadat (Gofa), south Ethiopia. [Coordinates estimated by Largen (2001): 6.33°N, 36.83°E, 2000 m a.s.l., but see remarks below]. Paralectotypes. Two adult males (ZMB-57183 = ZMB26879-2 and ZMB-57184 = ZMB26879-3) collected by Oscar Neumann on the same date and location as the lectotype (ZMB26879-1).

Material examined.

Except for the type series, all examined specimens are deposited at ZNHM. In addition to the type series, we examined one male (15-173) collected by X. Freilich, J. Reyes-Velasco and S. Boissinot on 9 August 2015 in Wondo Genet (7.0833°N, 38.6381°E, 1896 m a.s.l.), one female (15-181) and four males (15-183, 15-191, 15-208, 15-209) collected by X. Freilich, J. Reyes-Velasco and S. Boissinot on 12 August 2015 northwest of Bonga (7.3076°N, 36.1226°E, 1861 m a.s.l.), one female (16-203) collected on 18 July 2016 by J. Reyes-Velasco and S. Boissinot southwest of Bonga (7.2542°N, 36.2628°E, 1963 m a.s.l.), one female (16-302) and two males (16-303, 16-305) collected on 19 July 2016 by J. Reyes-Velasco and S. Boissinot north of Maji (6.2365°N, 35.5712°E, 1936 m a.s.l.), one female (16-326) and one male (16-313) collected on 20 July 2016 by J. Reyes-Velasco and S. Boissinot northeast of Machi (6.3780°N, 35.6659°E, 2063 m a.s.l.), two males (16-327, 16-329) collected on 20 July 2016 by J. Reyes-Velasco and S. Boissinot northeast of Mizan Teferi (7.0203°N, 35.7545°E, 2449 m a.s.l.), two females (SB333, SB334) collected on 9 June 2018 by S. Goutte and J. Reyes-Velasco northwest of Gore (8.2014°N, 35.3772°E, 1666 m a.s.l.), one male (SB388) collected on 11 June 2018 by S. Goutte and J. Reyes-Velasco south of Gech’a (7.5544°N, 35.4148°E, 1936 m a.s.l.), one female (SB405) collected on 13 June 2018 by S. Goutte and J. Reyes-Velasco south of Gech’a (7.5185°N, 35.4163°E, 1917 m a.s.l.), one female (SB462) collected on 20 June 2018 by S. Goutte and J. Reyes-Velasco northeast of Shebe (7.5423°N, 36.5732°E, 2240 m a.s.l.).

Diagnosis.

Medium-sized species (male (20) SVL 35.7 ± 2 mm, female (8) SVL 45.6 ± 1.4 mm) of the Ptychadena neumanni species group (Fig. 23 ) distinguished by the following combination of characters: (1) long hind limbs (male TL/SVL 0.58 ± 0.02, female TL/SVL 0.57 ± 0.01), (2) vertical cream bar on the tympanum, (3) vocal sacs uniformly dark grey.

Comparison.

Smaller than P. cooperi and P. goweri and larger than P. nana and P. robeensis sp. nov. Head wider than P. erlangeri and P. levenorum but narrower than P. beka sp. nov., Head and snout longer than P. erlangeri and P. levenorum . Wider inter-orbital distance than P. doro sp. nov., P. beka sp. nov., P. erlangeri , P. levenorum , and P. amharensis . Wider inter-nares distance and longer eye-nostril distance than P. erlangeri and P. levenorum . Tympanum larger than P. doro sp. nov., P. erlangeri , and P. levenorum . Larger hands than P. erlangeri and P. levenorum . Longer thighs and feet than P. erlangeri , P. levenorum , P. amharensis , and P. beka sp. nov.

Description of the lectotype.

The lectotype is very desiccated (Fig. 24A ) and the description of some characters is hindered by the state of conservation of the specimen. Medium sized (SVL 32.2 mm), slender adult male. Snout pointed, projecting beyond the lower jaw. Interorbital distance 0.83 × eye diameter. Head longer than wide (HW/HL 0.80). Nostril half-way between the tip of the snout and the eye. Internarial distance 1.1 × interorbital distance. Tympanum 0.64 × eye diameter. Finger tips not expanded but rounded, with moderate subarticular tubercles. Finger formula: I<II<IV<III. Hand free of webbing. Hindlimbs elongated, with tibia length 0.57 × snout-vent length. Foot longer than thigh (FL/THL 1.1) and as long as tibia. Toe tips rounded. Subarticular tubercles small and round. Inner metatarsal tubercle present, external absent. Toe formula: I<II<III<V<IV. Foot webbing formula: Ie(1), IIi/e(1-2), IIIi/e(2-2), IVi/e(2-2), Vi(2). Two light, continuous lateral ridges, six dorsal ridges difficult to see due to preservation of the specimen. No vertebral nor sacral ridges. Small warts on the body. No sacral, femoral, or crural folds.

Coloration of the lectotype in preservative.

Coloration has faded away with time and some patterns are now hardly distinguishable. Dorsal background color is brown, with irregular elongated dark brown blotches distributed along the dorsal ridges and on the antero-dorsal part of the flanks. A wide light vertebral line from snout to vent is present. Dark brown canthal stripe from the tip of the snout to the back of the jaw. Vocal sacs dark grey. Upper lip, throat, and posterior part of flanks cream. Ventrum, ventral side of the thighs and tibias uniformly cream in type 1. Barely distinguishable irregular dark brown bars on the tibias and on the thighs.

Variations.

In life, background color varies from light to dark brown. Dorsal ridges vary in number and definition. Lateral ridges may be sand or dark orange. All specimens examined had small dark brown or black blotches distributed symmetrically on the dorsal ridges. Flanks more or less heavily colored with black or dark brown blotches. Vertebral stripe absent in some individuals. When present, the vertebral stripe may be thin or wide, sand-color or brown-orange.

Iris bicolored, the upper third silver and lower two thirds dark brown sometimes marbled with light yellow or copper on the bottom half. Upper jaw cream, lower jaws featuring irregular light grey or brown markings but no barring. All specimens examined featured a dark brown canthal stripe from the tip of the snout to the back of the upper jaw and a with a cream vertical stripe. A thin cream longitudinal stripe on the tibia present in some individuals. Tibias, thighs, and feet posteriorly barred with more or less defined brown or light brown markings. Some individuals have dark irregular markings on the posterior side of the arms and anteroventral sides of the thighs and tibias. Thighs posteriorly marbled with dark brown and yellowish brown. Ventrum and throat uniformly cream to yellow. Vocal sacs grey to dark grey. Small warts over the back and flanks in adult males.

Habitat, distribution, and natural history.

Ptychadena neumanni is found on both sides of the Great Rift Valley (GRV) and limited to the south and southwestern highlands of Ethiopia (5.80-8.20°N, 35.36-38.64°E). This species is found at elevations ranging from 1409 m to 2449 m a.s.l. The southernmost individuals were found north of Hagere Mariam (east of the GRV) and Maji (west of the GRV). In the west, populations are found west of Gore, Gech’a, Bonga and Jimma. Ptychadena neumanni has also been found between Sodo and Bonga. East of the GRV it has been found in the vicinity of Wondo Genet. In the southwest, P. neumanni is found in syntopy with multiple Ptychadena species: P. doro sp. nov., P. delphina sp. nov., P. beka sp. nov., and the lowland species P. anchietae . In the southeast, it is found in sympatry with P. goweri . Males are found calling at night in shallow puddles on or beside the road, or in flooded grassy meadows.

Advertisement call.

Ptychadena neumanni produces two types of call, hereafter referred to as call type A and call type B. Based on our video recordings and observations in the field, we believe that call type A corresponds to the advertisement call, while call type B may be a territorial call. Notably, while calling in chorus, males were producing call type A, whereas call type B seem to be employed in two-individuals vocal battles. However, our data are insufficient to categorize with confidence these two calls with regard to their respective function and we describe both call types below. The call type and call rate produced is highly dependent on the social context.

Ptychadena neumanni call type A (3 males, 78 calls) is 307 ± 149 ms long and contains 5.8 ± 2.4 pulsed notes. Notes are 32 ± 14 ms in duration and are produced at regular intervals (19.1 ± 3.5 notes s-1) within each call. Amplitude modulation is very low within the call. Call type A’s dominant frequency is 2406 ± 339 Hz, with no frequency modulation within notes or calls.

Ptychadena neumanni call type B (1 male, 13 calls) is composed of one initial long (437 ± 54 ms) pulsed note (note B1), followed by 3 ± 0.6 distinct pulses (note B2). The peak frequency of note B1 is 2207 ± 129 Hz while note B2 has a dominant frequency of 2337 ± 191 Hz.

Call type A of P. neumanni can be distinguished from those of all other species of the P. neumanni complex, except for P. cooperi and P. amharensis , by its composition of multiple pulsed notes with indistinguishable pulses. It differs from the call of P. cooperi and P. amharensis by the absence of frequency modulation, shorter notes, and shorter inter-note intervals.

Call type B of P. neumanni is unique within the P. neumanni complex in its composition of two different types of notes and can easily be distinguished from those of all other species of the group.

Remarks.

Ahl (1924) described Rana neumanni based on 35 syntypes collected in Didda (one specimen), Somaliland (23 specimens), Gadat (Gofa) (three specimens), and Uba (eight specimens). Perret (1980) examined the type series, split the collection, and assigned the specimens to three distinct species. Perret designated the three specimens from Gadat (ZMB-26879 type 1, ZMB-26879 type 2 and ZMB-26879 type 3) as syntypes of Ptychadena neumanni (sensu stricto) as they were the only specimens with individual tags. Additionally, those specimens were the only ones of the original type series to have a collection date: 2 February 1901. Gadat (Gofa), south Ethiopia thus became Terra typica restricta of Ptychadena neumanni . Perret (1980) then revised the description of the species and gave measurement values for the three syntypes. When we examined the type series in the collection of the Museum of Berlin, we realized that the syntypes 2 and 3 had been attributed new collection numbers: ZMB-57183 (ZMB-26879 type 2) and ZMB-57184 (ZMB-26879 type 3) and the jar containing ZMB-26879 type 1 bears the label " lectotypus ". To our knowledge, no designation of ZMB-26879 type 1 as lectotype for P. neumanni has been published. Given that the original description of the species by Ahl (1924) included 35 syntypes and that the restriction by Perret (1980) is not valid according to the Code as it does not designate an individual specimen, we hereby designate ZMB-26879 (type 1) as a lectotype according to Article 74 of the International Zoological Code of Nomenclature ( ICZN 1999). The specimens ZMB-57183 (ZMB-26879 type 2) and ZMB-57184 (ZMB-26879 type 3) thus become paralectotypes.

Figures

Figure 23. Ptychadena neumanni A Live male (SB 393; left) and female (SB 388, right) B dorsal and ventral views of a male (SB 333, left) and a female (SB 388, right) after euthanasia and before fixation.

Figure 24. Type specimens of Ptychadena neumanni. Dorsal and ventral views of three male type specimens A ZMB 26879 - 1, lectotype B ZMB- 57183 = ZMB 26879 - 2, paralectotype C ZMB- 57184 = ZMB 26879 - 3, paralectotype.