Phrynobatrachus rainerguentheri, Rödel, Mark-Oliver, Onadeko, Abiodun B., Barej, Michael F. & Sandberger, Laura, 2012

Rödel, Mark-Oliver, Onadeko, Abiodun B., Barej, Michael F. & Sandberger, Laura, 2012, A new polymorphic Phrynobatrachus (Amphibia: Anura: Phrynobatrachidae) from western Nigeria, Zootaxa 3328, pp. 55-65 : 56-62

Phrynobatrachus rainerguentheri sp. nov.

Figs 1–2

Holotype. ZMB 77435, adult female, Nigeria, about 2 km from Ogun State University along Ijebu Ode ─ Ibadan road, Ogun river about 1 km to the East, close to the town of Ijebu Oru, N 06.93906°, E 003.94492°, <100 m a.s.l., 16 July 2004, coll. A.B. Onadeko.

Paratypes. ZMB 77436-77437, juveniles, 29 October 2011, type locality, similar location after 6-7 years of vegetation regrowth, other data as holotype; ZMB 77737-77744, all juveniles, Nigeria, Warri (Opara town), near the Niger Delta region, swampy area, N 05.51667°, E 005.73333°, 16 February 2012, coll. A.B. Onadeko.

Additional material. DZOOL 211, female, SVL 20.1 mm, 28 September 2003; DZOOL 384, female, 18.4 mm, 14 July 2004; all other data as holotype; DZOOL 544, juvenile, 10.1 mm, Nigeria, town of Warri, near the Niger Delta region, N 05.51667°, E 005.73333°, 18 November 2011, coll. A.B. Onadeko; DZOOL 545, female, 17.6 mm, 19 November 2011, other data as DZOOL 544.

Diagnosis. The genetic results show that the new species belongs to the genus Phrynobatrachus . Morphologically this is visible by the body shape; presence of a tarsal tubercle; presence of webbing; lack of a black spot in the tympanal region (as in Arthroleptis ); lack of a median dorsal skin raphe (as in Arthroleptis ); lack of parallel dorsal ridges (as in Ptychadena ); neither finger nor toe tips heart shaped (as in Petropedetes ) or expanded to discs.

The new species is characterised by a combination of small size; compact body shape; very short and round snout; large eyes, absence of an eyelid cornicle; presence of a conspicuous row of warts with pores on the upper mandible, larger warts on forehead and inter-orbital space; an almost smooth back, a pair of elongated chevron like ridges in the scapular region; an unmarked belly; the absence of discs on finger and toe tips and well developed webbing.

Description of holotype (measures in mm). Typical small Phrynobatrachus , female with oval, compact body shape; snout-vent length: 18.8; short snout, rounded in dorsal and lateral view; canthus rostralis indistinct and rounded; loreal region straight to slightly concave; head-width directly behind the eyes: 6.5; large protruding eyes; eye-diameter: 2.6; eyelids, forehead and inter-orbital space with few larger warts; eyelid cornicle absent; distance eye-nostril: 1.8; nares small, round, positioned dorsolaterally; distance nostril-snout tip: 1.3; nares closer to snout than to eye; inter-narial distance: 1.5; inter-orbital distance: 1.5; short supratympanal ridge; tympanum diameter: 1.4, indistinct, much smaller than diameter of eye; distinct row of warts with pores on upper lip; outline of lower mandible mucronate; upper maxilla with minute teeth, hidden by lips; vomerine teeth absent; broad cordiform tongue, tip slightly but broadly notched, median papilla near anterior attachment of tongue; back slightly granular; scapular region almost smooth, without distinct warts or ridges; ventral skin smooth; forelimbs slender; upper arm: 4.9; lower arm to tip of finger III: 8.2; hand with two large, outer round and inner oval carpal tubercles; fingers with small roundish subarticular tubercles, no additional tubercles on hands; relative finger length: IV≤I=II<III; right hand normal, left hand deformed with shortened digit I and II; rudimentary web on bases between fingers; finger tips not broadened; right hand normal; femur: 8.9, shorter than tibia: 10.3; foot including longest toe: 14.9; length of toe I: 2.6; tarsal tubercle present but not conspicuous; larger internal metatarsal tubercle (0.9), narrow and oval; app. 1/3 of length of toe I; external metatarsal tubercle not visible; relative toe length: I<II<V<III<IV; webbing formula I(0), II(0.5-0), III(1), IV(2), V(0.75); toe tips slightly enlarged without forming discs, just slightly exceeding width of subarticular tubercles.

Large eggs (largest egg app. 1 mm in diameter), rich in yolk, shining through skin of belly: 17 eggs visible; total egg number estimated to be app. 30, certainly not exceeding 50.

Colouration in life: black head and eyelids; black colour extending posteriorly just behind eye and to angle of mouth; tympanum coloured as back; back uniform orange-red; flanks slightly lighter than back; upper arms uniform brown; one dark cross bar on lower arms; fingers dorsally dark cross-bared; vent with black square, enclosed by light band; anterior part of thighs with two (right) and three (left) black cross bars, only one very distinct; posterior half of shanks uniform brown (right) and slightly mottled (left); shanks with three dark cross bars, only one very distinct; foot and toes dark cross-bared; throat, pectoral region and lower parts of flanks with minute brown spots; belly uniform light, almost translucent; ventral parts of feet brownish.

Colouration in formalin and ethanol after more than eight years: pattern slightly fainted, black head turned dark brown, reddish back turned to light brown.

Variation (measures summarised in Table 1 ). Snout-vent length in adult females from the type locality were 17.6-20.1 mm (adult males unknown), otherwise identical to holotype. The juvenile paratypes from the type locality are likewise very similar to holotype ( Fig. 2 ); snout-vent length 11.0 mm (ZMB 77436) and 9.6 mm (ZMB 77437, Fig. 2 i); snout in dorsal view round (ZMB 77436) or almost subelliptical (ZMB 77437); distinct larger warts between eyes (ZMB 77437) or this area smooth (ZMB 77436); row of warts on upper lip absent; shoulder with indicated chevron like ridges starting at posterior end of upper eyelid and extending app. to level of forearm bases (ZMB 77437) or smooth (ZMB 77436); back and flanks almost smooth as in holotype (ZMB 77436) or with small flat warts (ZMB 77437); basic coloration, in particular black head and red back as in holotype; lower mandible black; ventral border of flanks with black line (ZMB 77437) or spots (almost fusing, ZMB 77436); basic colour of extremities grey; posterior half of dorsal shanks uniform grey; vent with black square, surrounded by white band; lower arm, thighs and shanks with up to three black cross bars; belly white; sole of feet black; webbing less developed than in holotype or partly destroyed (dried up), the latter being more likely.

In contrast to the almost uniform specimens from the type locality, individuals from the second locality (all juveniles), near the town of Warri, exhibited considerable colour and some morphological variation. Only one specimen (ZMB 77741, Fig. 2 j) mirrored exactly the colour pattern and morphology of frogs from the type locality. All others have a distinct pair of elongated chevron like ridges in the scapular region ( Fig. 2 ). The enlarged warts on snout and the interorbital region are sometimes indistinct or missing. In contrast the flanks are warty and the back skin ranges from smooth to warty. The different colour morphs are illustrated in Fig. 2 . All specimens from both localities share a white or almost white belly, a white throat with small brown to black dots. The lower mandible is most often dark cross-barred. Some exhibit some large dark spots in the pectoral region and the lateral parts of the belly. Thighs and shanks may carry one or several dark cross bars. However, only one of these bars is particularly broad and distinct on thighs and shanks. In a sitting position the bars on upper and lower leg form one continuous band ( Fig. 2 ).

Genetics. Phrynobatrachus rainerguentheri sp. nov. differs between 6.59-22.94% in the investigated part of the 16S rRNA gene from 33 West African and Central African species of the genus Phrynobatrachus ( Table 2 ). The species with the lowest genetic divergence to P. rainerguentheri sp. nov. were P. ghanensis (mean difference 7.06%), P. phyllophilus (7.06%), P. guineensis (7.30%) and P. al le n i (8.55%). The intraspecific genetic variation of nine P. rainerguentheri sp. nov., one from the type locality (ZMB 77437, GenBank JQ730857 ) and eight from Warri (ZMB 77737-77744, GenBank JQ954860 - JQ954867 ) was 0-0.27%.

Habitat. Five of the 15 known individuals have been collected at the type locality during and towards the end of the rainy season in tertiary farmbush vegetation where large mango trees were forming a “forest” canopy. The understorey was sparsely vegetated and the area was muddy with water filled tracks. There the species seemed to be rare and hard to detect. First surveys, covering app. 400 m ² at the type locality, ranged from June 2003 to December 2004. During that period only three specimens were observed and collected. Although repeatedly revisiting the site, we could not observe the species until September/ November 2011. In late 2007 about 60% of the area was clear-cut during shifting agricultural practices ( Fig. 3 a). By the end of 2008 vegetation started to recover and in September 2011 two specimens could be observed and collected. At the type locality all specimens were collected in drier places far away from open water.

Species GenBank # voucher p-distance

min-max mean ±sd Other anuran species at the type locality where: Silurana tropicalis, Amietophrynus maculatus, A. regularis, Aubria subsigillata, Ptychadena cf. aequiplicata, Phrynobatrachus latifrons , P. francisci , Arthroleptis sp., Leptopelis sp., Afrixalus dorsalis, Hyperolius concolor and H. fusciventris ( Onadeko & Rödel 2009). This species composition indicates that the area originally consisted of rainforest. However, the many invasive species, i.e. the two toads and the two other Phrynobatrachus spp., are clearly indicating a heavily altered state of this forest habitat.

Most recently (18 & 19 November 2011, 16 February 2012) several additional specimens were recorded near the town of Warri, close to the Niger Delta region ( Fig. 3 b-e). Here the frogs, all juveniles, occurred in a dried up swamp in the leaf litter close to a drying pond (about 9 m in diameter) with some water remaining. During the rainy season this entire area is covered with water.

Distribution. Phrynobatrachus rainerguentheri sp. nov. is known from the type locality and one further locality app. 250 km south-east from the type locality ( Fig. 4 ).

Etymology. The species is dedicated to Dr. sc. Rainer Günther, from 1985-2006 curator of herpetology at the Museum für Naturkunde Berlin, in recognition for his outstanding contributions to herpetology.

Figures

FIGURE 1. Dorsal (a), ventral (b) and portrait (c) views, left hand (d, digits I and II deformed) and right foot (e) of the female holotype (ZMB 77435) of Phrynobatrachus rainerguentheri sp. nov.

FIGURE 2. Colour variation of Phrynobatrachus rainerguentheri sp. nov. from western Nigeria (paratypes and individuals which were not collected); a: not collected; b: ZMB 77737; c: ZMB 77744; d: ZMB 77739; e: ZMB 77738; f: ZMB 77740; g: not collected; h: ZMB 77743; i: ZMB 77437; j: ZMB 77741; k: ZMB 77742; l: not collected.

FIGURE 3. Habitats of Phrynobatrachus rainerguentheri sp. nov. in western Nigeria; a: type locality (N 06.93906 °, E 003.94492 °) with highly degraded vegetation after slash and burn agriculture; b-d: habitats in the dry season, close to Warri, near the Niger Delta region (N 05.51667 °, E 0 0 5.73333 °); c & e: locality where most paratypes have been collected; d: this entire area is flooded during the rainy season, most P. rainerguentheri sp. nov. were found close to the drying water among leaves.

FIGURE 4. Geographic position of the two known sites of Phrynobatrachus rainerguentheri sp. nov. in western, Nigeria (white symbols); type locality indicated with star (map based on the ASTER Global Digital Elevation Model: www. ersdac. or. jp.).

Tables

TABLE 1. Morphometric measures of Phrynobatrachus rainerguentheri sp. nov.; due to the preservation state of some individuals, collection of some measures was partly not possible; * = holotype; ** = paratypes; f = female; juv = juvenile; SVL = snout-vent-length; HW = head width directly behind the eyes; ED = eye diameter; DEN = distance eye-nostril; DNS = distance nostril-snout tip; IND = internarial distance; IOD = interorbital distance; TD = tympanum diameter; UA = upper arm length; LAFIII = lower arm to tip of digit III; FL = femur length; TL = tibia length; FLT = foot length including longest toe; LT = length of longest toe; all measures in mm.

	sex	SVL	HW	ED	DEN	DNS	IND	IOD	TD	UA	LAFIII	FL	TL	FLT
ZMB 77435*	f	18.8	6.5	2.6	1.8	1.3	1.5	1.5	1.4	4.9	8.2	8.9	10.3	14.9
ZMB 77436**	juv	11.0	3.3	1.4	1.5	1.0	1.3	1.2	0.7	2.4	4.7	6.2	6.6	7.5
ZMB 77437**	juv	9.6	3.3	1.8	0.9	0.6	1.1	1.3	0.7	2.7	-	5.2	5.6	7.6
ZMB 77737**	juv	11.0	3.6	2.1	1.1	1.0	1.3	1.4	1.0	2.5	-	6.3	6.2	8.1
ZMB 77738**	juv	12.0	4.2	2.1	1.4	0.9	1.5	1.7	1.1	2.5	-	5.9	6.8	8.9
ZMB 77739**	juv	10.5	3.6	1.7	1.2	0.7	1.1	1.5	0.7	2.0	3.9	5.1	5.4	7.3
ZMB 77740**	juv	11.0	3.9	1.9	1.2	0.9	1.1	1.2	-	3.0	-	5.4	6.6	-
ZMB 77741**	juv	10.3	3.9	1.8	1.1	0.9	1.2	1.5	-	2.1	4.3	5.3	6.0	7.7
ZMB 77742**	juv	9.2	3.7	1.8	1.1	0.8	-	1.4	0.8	1.8	3.8	5.2	4.7	-
ZMB 77743**	juv	11.0	3.7	1.8	-	-	-	1.1	-	-	-	5.1	5.7	7.3
ZMB 77744**	juv	10.6	3.0	1.7	1.5	1.3	1.6	1.6	1.3	2.1	-	6.1	6.3	-
DZOOL 211	f	20.1	8.0	3.0	-	1.8	1.6	-	-	4.9	8.1	9.0	11.0	13.8
DZOOL 384	f	18.4	7.6	2.4	-	1.3	1.5	-	-	4.1	7.5	8.4	10.3	12.6
DZOOL 545	f	17.6	7.4	2.4	-	1.1	1.4	-	-	4.0	7.1	8.1	9.9	11.9
DZOOL 544	juv	10.1	4.0	1.1	-	0.9	0.8	-	1.1	2.0	4.2	4.7	5.0	7.1

TABLE 2. Genetic similarity of West and western Central African Phrynobatrachus species with nine Phrynobatrachus rainerguentheri sp. nov. (ZMB 77437, JQ 730857; ZMB 77737, JQ 954860; ZMB 77738, JQ 954861; ZMB 77739, JQ 954862; ZMB 77740, JQ 954863; ZMB 77741, JQ 954864; ZMB 77742, JQ 954865; ZMB 77743, JQ 954866; ZMB 77744, JQ 954867). Given are collection accession numbers of vouchers and / or tissue samples, GenBank accession numbers and the respective uncorrected pairwise sequence divergence (in % of app. 517 bp of the 16 S rRNA gene).

P. a c r i d o i d e s	DQ022358	AC1251	12.97–14.51	13.57 ± 0.01
P. africanus	FJ769116	CAS 207779	11.88–14.06	12.72 ± 0.01
P. alleni	GU457535	ZMB 73747	8.08–9.57	8.55 ± 0.01
P. annulatus	GU457538	ZMB 73746	16.96–18.44	17.83 ± 0.01
P. auritus	DQ283084	UTA A44704	14.62–17.77	15.62 ± 0.01
P. b a t e s i i	JQ711171	ZFMK 89444	11.86–13.78	12.69 ± 0.01
P. calcaratus	DQ283240	CAS199268	17.05–19.00	17.81 ± 0.01
P. chukuchuku	FJ769104	MCZ A138125	11.45–13.76	12.42 ± 0.01
P. c o r n u t u s	GU457545	ZMB 73784	15.14–16.97	15.83 ± 0.01
P. cricogaster	FJ769100	ZMB 71458	12.28–15.20	13.46 ± 0.01
P. danko	GU732283	MCZ A139531	13.32–16.03	14.32 ± 0.01
P. dispar	DQ283223	CAS 218995	13.80–15.10	14.43 ± 0.00
P. f r a n c i s c i	GU457549	ZMB 73779	13.61–16.48	14.73 ± 0.01
P. fraterculus	GU457551	ZMB 73761	18.17–20.49	19.05 ± 0.01
P. ghanensis	GU457553	ZMB 70721	6.59–7.85	7.06 ± 0.01
P. guineensis	GU457555	MOR T13	6.77–8.06	7.30 ± 0.01
P. gutturosus	GU457556	MOR C11	18.22–20.28	19.12 ± 0.01
P. intermedius	FJ415751	ZMB 71538	13.56–16.73	14.59 ± 0.01
P. latifrons	GU457559	ZMB 73753	16.17–18.58	17.07 ± 0.01
P. leveleve	EU075280	CAS 218906	13.76–15.14	14.42 ± 0.00
P. liberiensis	FJ415766	MOR JP0151	13.35–16.21	14.34 ± 0.01
P. maculiventris	GU457564	ZMB 71593	16.60–18.69	17.39 ± 0.01
P. manengoubensis	FJ769110	MCZ A136924	13.03–15.96	14.16 ± 0.01
P. natalensis	GU457566	ZMB 73717	14.69–17.52	15.64 ± 0.01
P. phyllophilus	GU457570	ZMB 73763	6.82–7.63	7.06 ± 0.00
P. pintoi	JN813914	ZMB 76879	18.95–21.33	19.73 ± 0.01
P. plicatus	AY902376	MOR S01 41	14.79–16.60	15.26 ± 0.01
P. sandersoni	GU457577	MCZ A136791	20.03–22.94	20.97 ± 0.01
P. s c h i o e t z i	FJ769112	MVZ253334	15.26–17.93	16.37 ± 0.01
P. steindachneri	FJ769095	MCZ A136875	11.66–14.03	12.57 ± 0.01
P. t o k b a	GU457582	MOR FD90	17.60–20.81	18.78 ± 0.01
P. villiersi	GU457589	ZMB 73740	15.46–16.72	15.90 ± 0.00
P. w e r n e r i	GU732284	MCZ A138074	12.42–14.88	13.39 ± 0.01