Kouamé_etal_Roedel_etal_Rediscovery_hyperolius_nimbae_heRPeTozoA.qxd 08.08.2016 10:08 Seite 1

heRPeTozoA 29 (1/2): 3 - 13 3 Wien, 30. Juli 2016

Rediscovery of the Mount Nimba Reedfrog, nimbae LAuReNT , 1958, in western (Anura: )

Wiederentdeckung des Mount Nimba Riedfrosches, Hyperolius nimbae LAuReNT , 1958 im Westen der elfenbeinküste (Anura: hyperoliidae)

N’G oRAN GeRMAIN KouAMé & N’G ueSSAN eMMANueL ASSeMIAN & b LAydA Tohé & P ATRICK JoëL AdebA & G eRMAIN GouRèNe & M ARK -o LIveR RödeL

KuRzFASSuNG

die vorliegende Arbeit berichtet über die Wiederentdeckung von Hyperolius nimbae LAuReNT , 1958, einer Riedfroschart, die nur vom Fuß der östlichen Flanke des Mount Nimba im Westen der elfenbeinküste bekannt ist. die Art wurde 1958 beschrieben und 1963 zum letzten Mal beobachtet. Siebenundvierzig Jahre später wurden innerhalb des bekannten verbreitungsgebietes, kleine Populationen dieses Riedfrosches in der Nähe der dörfer dagbonpleu, danipleu, Kouan-houlé und zéalé wiederentdeckt. Allerdings konnten nur insgesamt sieben exemplare registriert werden. die Lebensräume zeigten unterschiedliche Grade der degradierung von Sumpf- wäldern bis zu Reisfeldern in degradiertem Wald oder Sekundärwuchs. der starke menschliche einfluß im Gebiet, besonders seine landwirtschaftliche Nutzung, könnte das langfristige Überleben der Art gefährden. die Autoren empfehlen eine intensive weitere Suche nach bestehenden Populationen und deren Monitoring, um die Gefährdung für das Überleben von H. nimbae abzuschätzen. AbSTRACT

The authors report the rediscovery of Hyperolius nimbae LAuReNT , 1958, a reedfrog known only from the lowlands of the eastern flanks of Mount Nimba, western Ivory Coast. The species was described in 1958 and last seen in 1963. Forty-seven years after that date small populations were rediscovered near four villages, dagbonpleu, danipleu, Kouan-houlé and zéalé, within the formerly known range. however, only a total of seven individuals were recorded. The showed various degrees of degradation, ranging from swampy forest to rice fields within degraded forest and secondary growth. The strong anthropogenic impact, in particular agricul - tural activities, may be an imminent risk compromising the species’ long-term survival. The authors recommend further intensive search for persisting populations and their monitoring to evaluate the factors threatening the sur - vival of H. nimbae . Key WoRdS Amphibia: Anura: hyperoliidae; Hyperolius nimbae , reedfrog, biodiversity hotspot, conservation status, Mount Nimba endemic, Côte d’Ivoire, Ivory Coast, upper

INTRoduCTIoN

The Mount Nimba massif is located in summaries were published by GuIbé & L A - the border region collectively shared by the MoTTe (1958, 1963) and LAuReNT (1958). West African countries , Guinea and The flagship species of the massif is the en- Ivory Coast ( LAMoTTe 1983, 1998). These demic Nimba Toad, occi - mountains harbor a rich endemic fauna and dentalis (ANGeL , 1943), the only truly vivip - flora ( LAMoTTe & R oy 2003), including arous anuran species worldwide ( LAMoTTe reptiles ( INeICh 2003) and 1959; XAvIeR 1986; LAMoTTe & S ANChez - (RödeL et al. 2004). The fauna LAMoTTe 1999; hILLeRS et al. 2008; SANd- is dealt with in numerous publications. First beRGeR et al. 2010). Recently two spe- Kouamé_etal_Roedel_etal_Rediscovery_hyperolius_nimbae_heRPeTozoA.qxd 08.08.2016 10:08 Seite 2

4 N’G. G. K ouAMé & N’G. e. A SSeMIAN & b. T ohé & P. J. A debA & G. G ouRèNe & M.-o. R ödeL

cies were described from the Liberian part tions started recently about the possibility of of the Nimba Massif ( Rö deL et al. 2009, the extinction of this reedfrog. Some 2010a). attempts to locate the species at other sites one species believed to be endemic to of close proximity to the known area, e.g., the Ivorian foothills of the Nimba Moun- the Mont Sangbé National Park ( RödeL tains was described in 1958 by LAuReNT 2003) and Guinean parts of the Nimba from “yanlé”, Ivory Coast, under the name mountains ( J. d ouMbIA , L. S ANdbeRGeR - Hyperolius viridiflavus nimbae . In July LouA & M.-o. R ödeL , unpublished data), 1963, the danish herpetologist ARNe revealed no records. SChIøTz collected a larger series (28 males, Ivory Coast is quoted among the coun - 5 females) of the species between the tries where rainforests are the most threat - Ivorian settlements danané and zéalé, ened in the world ( hANSeN et al. 2013). As approximately 40 km south-east of the a result of large scale deforestation, almost Mount Nimba chain ( SChIøTz 1967). 80 % of the forests in the western part of the SChIøTz (1967) raised LAuReNT ’s (1958) country were destroyed up to the end of the taxon to species level, compared it to other last millennium ( PARReN & de GRAAF 1995; treefrog species, provided first biological ChATeLAIN et al. 1996). The only sites from data and, in particular, wondered why the where H. nimbae was known face severe range of this species was so restricted as its anthropogenic impact. The former rainfor - preferences seemed to be by no way est area is now largely dominated by an particular. Later, LAuReNT (1983) and agricultural landscape ( N. G. K ouAMé , pers. SChIøTz (1971) considered this frog a sub - obs.). species of Hyperolius tuberculatus (MoC- In 2010, Conservation International quARd , 1897), a species otherwise known initiated the campaign “Search For the Lost from western Central Africa ( AMIeT 2012; ”, focusing on the search for 100 FRéTey et al. 2012). In a subsequent publi - amphibian species that have not been seen cation, SChIøTz (1999) again recognized H. for decades, but scientists believe may have tuberculatus and H. nimbae as distinct survived (compare e.g., oNAdeKo et al. species. SChIøTz ’s observations from July 2014 for a similar African example) . 28, 1963 seem to be the latest encounters Among these species, H. nimbae, not seen with the species in the wild. at that date for 47 years, was listed. This is Following the global awareness of a why the authors decided to reinvestigate the tremendous worldwide amphibian decline known range of H. nimbae and its surround - (e.g., bLAuSTeIN & K IeSeCKeR 2002; ings. The aim of the study was to rediscov - FeRRAz et al. 2003; STuART et al. 2004, er the Nimba Reedfrog and find further per - 2008; MooRe & ChuRCh 2008), specula - sisting populations.

MATeRIALS ANd MeThodS

Study area forest and smaller mountains. The regions of Man and danané are characterized by Surveys took place in the danané region swampy valleys between granite outcrops, of western Ivory Coast, south-east of the so-called inselbergs ( MouToN 1959). The Nimba Mountains. Mean annual tempera - surveyed sites comprised high grass areas, ture in danané (342 m a.s.l.) is 25.1 °C; farmland and degraded forests. Large parts mean annual precipitation 1,967 mm. The of this forest zone are subject to logging rainy season lasts between seven and nine activities. Field work was done at the months, with maximum precipitation in beginning of the core rainy season from 26 September; January is the driest month August to 1 September 2010. A hand-held (CLIMATe -d ATA .oRG 2015). The south- and GPS de vice (Garmin 12XL) was used to central-western part of Ivory Coast is natu - record the geographical positions of the rally covered by a mosaic of lowland rain - study sites (Table 1). Kouamé_etal_Roedel_etal_Rediscovery_hyperolius_nimbae_heRPeTozoA.qxd 08.08.2016 10:08 Seite 3

Rediscovery of Hyperolius nimbae LAuReNT , 1958 5 r f e o

Field work and vouchers

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t e h were measured and sexed. Morphometric c w a l

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a (N.G.K.) with a dial calliper (accuracy ± 0.5 , e u l t t ( o

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n g a b a e a ( b d

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d mm). They are given in mm and comprise m a c p a b d y k r d d d u d

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t behind eyes, length of head, width of gular p t 7 i p c

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diameter, horizontal tympanum diameter, e e e b i I d l l F p e

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a o g g g R n g c in a 1,1,1-trichloro-2-methyl-2-propanol d

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1 l l l n t l hemihydrate solution and thereafter pre -

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8 are deposited in the research collection of g l r t m 5 c e s u 9 n d e N.G.K. at the Jean Lorougnon Guédé uni- i

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T versity, , Ivory Coast. 8 N 5 e 9 R t 1

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t 1 0 0 0 2 2 2 m A m . . 0 . b

e a i . u t t t t L 7 0 8 b e The authors found the Nimba Reed - t n a 1 a a a d s 2 3 2 a

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a d frog in zéalé, Kouan-houlé (east of zéalé) e u n b i h l o i e m o and two other villages west of zéalé: dag- t i i r

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p bonpleu and danipleu. Altogether, seven s o g e c y i u t s t n i

i a H l e , , , , calling male Hyperolius nimbae (Table 1; ’ ’ ’ ’ u s

’ ’ ’ ’ n o d 9 5 1 7 f i b o

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1 Fig. 1) were heard. however, only one of 7 9 3 e

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6 them (from danipleu) was detected and 5 9 3 c c t 2 1 2 1 H i k a s 2 2 2 2 i ° ° ° °

t l ° h ° ° ° e h r 8 8 8 8 n

a captured. The others remained unseen in 7 p 7 7 7 b t o 0 0 0 0 c o t r a 0 0 0 0 d a r o v o t

l swampy habitats difficult to access.

n W W W W N N N N g i

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r F r e a The advertisement calls of an adult

d o o / G h n c d

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e male at zéalé consisted of a series of metal - n

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F e r lic click sounds that came from a clearing

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within a swampy forest (Fig. 1a). The frog 1 t l n e

d r u l . u u e n b b o o o

l seemed to call (after 19:00 GMT) perched u

a a c

p u / h

T T n e e - n l e between leaves on a tree, about three meters e h n o

p g c é a s i b l a s u l g n g above the water surface of a pond (surface a l ö a o a o i é r

r 2 F f v z d K d app. 200 m ) which was covered by algae; Kouamé_etal_Roedel_etal_Rediscovery_hyperolius_nimbae_heRPeTozoA.qxd 08.08.2016 10:08 Seite 4

6 N’G. G. K ouAMé & N’G. e. A SSeMIAN & b. T ohé & P. J. A debA & G. G ouRèNe & M.-o. R ödeL

Fig. 1: habitats of Hyperolius nimbae LAuReNT , 1958, in the surveyed area; a ‒ clearing in a swampy forest at zéalé; b ‒ thick shrubs with herbaceous swamps; c ‒ paddy field within a degraded forest (site where the single male H. nimbae was captured); d ‒ thick secondary growth with a dirt road leading to the Nimba Mountain range (in the background). Abb. 1: Lebensräume von Hyperolius nimbae LAuReNT , 1958 ; a ‒ Lichtung in einem Sumpfwald bei zéalé; b ‒ dichtes Gestrüpp mit von Kräutern bewachsenem Sumpf; c ‒ Reisfeld in einem degradierten Wald (hier wurde das einzige Individuum von H. nimbae gefangen); d ‒ dichter Sekundärwuchs mit einer Piste, die zum Mount Nimba Massiv führt (sichtbar im hintergrund).

water depth was ≥1.5 m. The site had an Hyperolius fusciventris PeTeRS , 1876 and open canopy, was surrounded by heavily Hyperolius guttulatus GÜNTheR , 1858. At degraded forest and located 150 m from a dagbonpleu, a male was heard at night settlement. Syntopic treefrog species were (20:12 GMT) outside the village at a site Chiromantis rufescens (GÜNTheR , 1869), dominated by farms and swamps. Syntopic Leptopelis spiritusnoctis RödeL , 2007 and treefrogs were A. dorsalis , H. concolor , Kassina cochranae (LoveRIdGe , 1941) Hyperolius picturatus PeTeRS , 1875, and H. (Table 2). At Kouan-houlé, H. nimbae was guttulatus . heard calling after dusk (19:04 GMT). This Close to danipleu village, near the site was characterized by thick shrubs, a Liberian border, approximately seven km swamp with dense herbaceous vegetation east of the Nimba Mountain (Figs. 1c, 1d), and a nearby paddy field. The calls seemed four male H. nimbae were heard calling on to come from a shrub at two meters above 1 September 2010 around 21:33 h during a the ground. Syntopic treefrog species at this heavy rainfall. The site consisted of a pond site were Afrixalus dorsalis (PeTeRS , 1875), and paddies surrounded by degraded forest (hALLoWeLL , 1844), and thick shrubby vegetation. one male Kouamé_etal_Roedel_etal_Rediscovery_hyperolius_nimbae_heRPeTozoA.qxd 08.08.2016 10:08 Seite 5

Rediscovery of Hyperolius nimbae LAuReNT , 1958 7

Fig. 2: Male Hyperolius nimbae LAuReNT , 1958, from danipleu, a village situated seven km south-east to Mount Nimba, western Ivory Coast; note the warty dorsal skin and reddish thighs. Abb. 2: Männchen von Hyperolius nimbae LAuReNT , 1958 aus danipleu, einem dorf in der westlichen elfenbeinküste, ca. sieben km südöstlich des Mount Nimba; man beachte die warzige Rückenhaut und die roten hautpartien der oberschenkel.

was captured when perched at breast height larger than internarial space (3.5 mm) and on a shrub at the edge of a paddy. The other tympanum diameter (2.5 mm); width of the individuals stopped calling upon the ap - oval gular gland 9.0 mm; tibia-fibula length proach of their calling sites situated at a (16.0 mm), slightly exceeding femur length large pond, in part covered by floating aqua - (14.0 mm); foot length including longest toe tic plants ( Nymphaea spp.) and bordered by 21.5 mm. grass. The syntopic treefrog species en- The color pattern in life was within the countered were H. concolor , H. fusciventris range of phase F sensu SChIøTz (1967) and (calling males very abundant) and A. dor - is well visible on Figures 2a-2d and 3a-3b. salis . discs on toes were small and slightly red - The captured male (NGK-NIMbA01) dish to greenish. The webbing was well- measured 33.0 mm SuL, thus being within developed between toes and fingers (Figs. the known range of H. nimbae (SChIøTz 2b, 2d). The dorsal skin was coarsely gran - 1967): head slightly longer (11.0 mm) than ulated with numerous dark brown and few broad (9.0 mm); interorbital space 6.5 mm; orange spots (Figs. 2a-2c, 3a). The hidden distance between eye and nostril (2.5 mm) skin parts of the thighs, as well as all lower exceeded distance from nostril to tip of parts of the hind limbs were red. The throat snout (1.5 mm); eye diameter (4.5 mm) was greenish brown, the gular gland dark Kouamé_etal_Roedel_etal_Rediscovery_hyperolius_nimbae_heRPeTozoA.qxd 08.08.2016 10:08 Seite 6

8 N’G. G. K ouAMé & N’G. e. A SSeMIAN & b. T ohé & P. J. A debA & G. G ouRèNe & M.-o. R ödeL

Table 2: Anuran species recorded in the danané area, including site (see Table 1), general habitat prefer - ence, distribution range and IuCN Red List category. dag ‒ dagbonpleu, dan ‒ danipleu, Kou ‒ Kouan-houlé, zéa ‒ zéalé, S ‒ savannah, Fb ‒ farmbush (degraded forest and farmland), F ‒ forest, A ‒ Africa (occurs also outside ), WA ‒ West Africa (defined as the area West of the Cross River in , see PeNNeR et al. 2011), uG ‒ (forest zone west of the dahomey Gap), e ‒ endemic to Ivory Coast, * ‒ taxon com - prises a complex of several species, ** ‒ records comprise several species (based on acoustics; morphology indis - tinguishable; see RödeL & b ANGouRA 2004), LC ‒ Least Concern, NT ‒ Near Threatened, eN ‒ endangered. Tab. 2: Nachweise von Anurenarten aus der danané Region. Angegeben sind Fundort (siehe Tab. 1), bevorzugter Lebensraum, verbreitungsgebiet und IuCN Rote Listen Kategorie. dag ‒ dagbonpleu, dan ‒ danipleu, Kou ‒ Kouan-houlé, zéa ‒ zéalé, S ‒ Savanne, Fb ‒ degradierter Wald und Sekundärwuchs, F ‒ Wald, A ‒ Afrika (kommt auch außerhalb Westafrikas vor), WA ‒ Westafrika (definiert als das Gebiet westlich des Cross Rivers in Nigeria, siehe PeNNeR et al. 2011), uG ‒ upper Guinea (Waldzone westlich der dahomey Regenwaldlücke), e ‒ endemisch für die elfenbeinküste, * ‒ Komplex kryptischer Arten, ** ‒ Nachweise umfassen mehrere Arten (unterschieden nach Akustik; morphologisch nicht unterscheidbar; siehe RödeL & bANGouRA 2004), LC ‒ Least Concern, NT ‒ Near Threatened, eN ‒ endangered.

Family / Species Site / habitat distribution range IuCN Familie / Art Fundort / verbreitung Red List S Fb F A WA uG e Category Arthroleptidae Arthroleptis spp.** zéa XX X LC Astylosternus occidentalis PARKeR , 1931 Kou XXLC Leptopelis spiritusnoctis RödeL , 2007 Kou, zéa XX X LC Leptopelis occidentalis SChIøTz , 1967 zéa XXNT bufonidae Amietophrynus maculatus dag, Kou, zéa XX X LC (h ALLoWeLL , 1854) Amietophrynus regularis (R euSS , 1833) Kou, zéa XX X LC dicroglossidae Hoplobatrachus occipitalis dag, zéa XX X LC (G ÜNTheR , 1858) hemisotidae Hemisus marmoratus (P eTeRS , 1854) dag, zéa XX X LC hyperoliidae Afrixalus dorsalis (P eTeRS , 1875) dag, dan, Kou, zéa XX X LC Afrixalus fulvovittatus fulvovittatus Kou, zéa XX X LC (C oPe , 1861) Hyperolius concolor concolor dan, Kou, zéa XX X LC (h ALLoWeLL , 1844) Hyperolius fusciventris fusciventris dan, dag, Kou, zéa XX X LC PeTeRS , 1876 Hyperolius guttulatus GÜNTheR , 1858 dag, Kou, zéa XX LC Hyperolius lamottei LAuReNT , 1958 Kou XXLC Hyperolius igbettensis SChIøTz , 1963 Kou, zéa XXLC Hyperolius nimbae LAuReNT , 1958 dan, dag, Kou, zéa XXeN Hyperolius picturatus PeTeRS , 1875 dag, Kou, zéa XX X LC Kassina cochranae (L oveRIdGe , 1941) dan, Kou, zéa XXNT Phrynobatrachidae fraterculus Kou XX X LC (C hAbANAud , 1921) Phrynobatrachus gutturosus dan, dag, zéa XXX X LC (C hAbANAud , 1921) * Phrynobatrachus latifrons AhL , 1924 dan, dag, Kou, zéa XX X LC Phrynobatrachus liberiensis zéa XXNT bARbouR & L oveRIdGe , 1927 Phrynobatrachus phyllophilus dag, Kou XXNT RödeL & e RNST , 2002 Phrynobatrachus plicatus (G ÜNTheR , 1858) dag, Kou, zéa XX LC Phrynobatrachus natalensis (S MITh , 1849) dag, zéa XX LC Phrynobatrachus tokba (C hAbANAud , 1921) dan, dag, zéa XX X LC Pipidae Xenopus tropicalis (G RAy , 1864) dan, Kou, zéa XXX LC Kouamé_etal_Roedel_etal_Rediscovery_hyperolius_nimbae_heRPeTozoA.qxd 08.08.2016 10:08 Seite 7

Rediscovery of Hyperolius nimbae LAuReNT , 1958 9

Table 2 (continued from the opposite page): Anuran species recorded in the danané area. Tab. 2 (Fortsetzung der gegenüberliegenden Seite): Nachweise von Anurenarten aus der danané Region.

Family / Species Site / habitat distribution range IuCN Familie / Art Fundort / verbreitung Red List S Fb F A WA uG e Category longirostris (P eTeRS , 1870) dag, Kou, zéa XX LC Ptychadena mascareniensis dan, Kou, zéa XX X LC (d uMéRIL & b IbRoN , 1841) * Ptychadena pumilio (b ouLeNGeR , 1920) dag, Kou XX X LC subsigillata (d uMéRIL , 1856) dan, zéa XX LC Ranidae Hylarana albolabris (h ALLoWeLL , 1856) Kou, zéa XXX LC Rhacophoridae Chiromantis rufescens (G ÜNTheR , 1869) zéa XX LC

greyish-yellow and coarsely granulated tion range and the IuCN Red List category (Fig. 3b). The remaining ventral skin was is given (Table 2). More than one third (13 white. spp., 39.4 %) of all recorded species are during the seven-day survey in the endemic to the upper Guinea forest zone danané region, the authors recorded at least (forests west of the dahomey Gap), while 33 amphibian species; a list with site H. nimbae was the only recorded species records, known habitat preference, distribu - endemic to the Nimba Mountains.

dISCuSSIoN

Frogs living in farmbush (degraded particular, he reported numerous H. nimbae forest and farmland) habitats are believed to from two sites at presumably temporary be comparatively widespread and abundant swamps within clearings surrounded by (see examples in SChIøTz 1967; RödeL high grass. The area at that time was 2000; AMIeT 2012). Hyperolius nimbae is already heavily cultivated, although neigh - such a farmbush species, probably related to boring the dense and humid forest of the the forest zone but living in degraded habi - Mount Nimba massif. The frog fauna which tats. According to SChIøTz (1967) H. nim - he recorded from that area reflects the mix - bae was abundant, and already then seemed ture of primary forest (e.g., Kassina lamot - to be restricted to a small area in a forested tei SChIøTz , 1967, Leptopelis macrotis SChI- region south-east of the . In øTz , 1967, Afrixalus nigeriensis SChIøTz , absence of a distinct geographic barrier, the 1963) and farmbush habitats (e.g., Kassina spatial restriction of the range was not cochranae , Leptopelis spiritusnoctis , A. understood, the more so as the species obvi - dorsalis ) at that time. Another frog species ously tolerated degraded habitats. mentioned by SChIøTz (1967) for the H. The present account details the nimbae sites, is H. concolor , however, being species’ rediscovery, 52 years after its less abundant than the Nimba Reedfrog. description and 47 years after it has been Hyperolius concolor is a typical farmbush seen for the last time in the wild. All four species ( SChIøTz 1967; RödeL 2000) and observation sites mentioned here are within was also recorded at three of the four new the formerly known range. SChIøTz (1967) H. nimbae sites. reported that the species was patchily dis - At present, the entire area is largely tributed, but abundant where it occurred. In dominated by agricultural land. The remain - Kouamé_etal_Roedel_etal_Rediscovery_hyperolius_nimbae_heRPeTozoA.qxd 08.08.2016 10:08 Seite 8

10 N’G. G. K ouAMé & N’G. e. A SSeMIAN & b. T ohé & P. J. A debA & G. G ouRèNe & M.-o. R ödeL

Fig. 3: Life coloration of an adult male Hyperolius nimbae LAuReNT , 1958 , and two Hyperolius species to which H. nimbae was previously assigned at the level, i.e., PeTeRS , 1875, and Hyperolius tuberculatus (M oCquARd , 1897) ; a ‒ dorsolateral view of H. nimbae male, color pattern phase F from danipleu, danané, remark the coarsely granulated skin; b ‒ ventral view of H. nimbae , throat greenish brown with smaller, roundish, dark greyish-yellow gular gland flap; c ‒ dorsolateral view of H. nitidulus male from daloa urban area (central-western Ivory Coast), remark the numerous small warts on skin; d ‒ ventral view of H. nitidulus , throat yellow with very large yellow gular gland; e ‒ dorsolateral view of H. tuberculatus male from near dja forest, , remark the granular skin; f ‒ ventral view of H. tuberculatus , throat white and gular gland greenish-brown. Abb. 3: Lebendfärbung von männlichen Hyperolius nimbae LAuReNT , 1958 und zwei anderen Riedfroscharten, denen H. nimbae früher als unterart zugeordnet war, Hyperolius nitidulus PeTeRS , 1875 und Hyperolius tuberculatus (M oCquARd , 1897) ; a ‒ dorsolateralansicht von H. nimbae (Männchen der Farbvariante F) aus danipleu, danané, Kouamé_etal_Roedel_etal_Rediscovery_hyperolius_nimbae_heRPeTozoA.qxd 08.08.2016 10:08 Seite 9

Rediscovery of Hyperolius nimbae LAuReNT , 1958 11

ing forests show clear traces of previous and e.g., PeNNeR et al. 2011; RödeL et al. 2014). ongoing human impact, e.g., logging, roads In contrast to the species mentioned by and tracks, absence of a closed canopy and AMIeT (2012), H. nimbae is an extremely clearings in forested parts. The Nimba range-restricted taxon and not known to Reedfrog was rediscovered in similar habi - occur outside its minute range on the eastern tats as originally described by SChIøTz foothills of Mount Nimba. The high rate of (1967), however, the sites were probably endemism at this mountain range is usually even more degraded, and the frogs much explained by the mountain’s supposed role lower in number. This low number may as a Pleistocene forest refugium (e.g., have different reasons. SChIøTz (1967) ob - PARReN & de GRAAF 1995; MALey 1996; served the species late in July, the authors’ PooRTeR et al. 2004), which could account records date from end of August, early Sep - for the small range of H. nimbae . tember. differences in abundances thus may unfortunately there is no tissue avail - be due to the breeding phenology, although able appropriately preserved to test for the this is not a very likely explanation as most phylogenetic relationships of H. nimbae with West African Hyper olius species are pro - other West and Central African Hyperolius. longed breeders, being present at the breed - however, the following traits support the ing sites for most of the rainy season ( SChI - assumption that H. nimbae is indeed a valid øTz 1967; RödeL 2000). Nevertheless, the species (compare SChIøTz 1967, 1999; numbers of calling males can vary from day RödeL 2000; RödeL et al. 2010b; AMIeT to day, e.g., correlated with actual precipita - 2012): (i) its restricted range at this particu - tion ( KouAMé and RödeL , unpublished lar mountain area, (ii) the acoustic differ - data). The current findings, thus do not ences to H. nitidulus PeTeRS , 1875, and H. allow to judge or comment on potential pop - tuberculatus (H. nitidulus: single note calls; ulation trends. More in-depth assessments H. nimbae and H. tuberculatus : multinote of the distribution and abundance of the calls, the notes of H. tuberculatus being Nimba Reedfrog in the danané area are thus repeated at a higher rate but lower frequen - desirable. cy; see SChIøTz 1999), (iii) differences in As outlined in the introduction, H. size (SuL of adult males: H. nitidulus : 23- nimbae has a variable taxonomic history, 26 mm, H. nimbae : 30-37 mm, H. tubercu - being regarded as a distinct species or sub - latus : 28-32 mm; SChIøTz 1999; R ödeL species to different Hyperolius species (Fig. 2000 ) and (iv) skin morphology under wet 4). Whereas, SChIøTz (1999) finally regard - season conditions ( H. nitidulus : smooth; H. ed it a species of its own, AMIeT (2012) con - tuberculatus : granular; H. nimbae : granular siders still possible that H. nimbae is a West with protruding round warts, compare Fig. African population of H. tuberculatus , rep - 3), as well as (v) different habitat require - resenting another typical example of the dis - ments (farmbush: H. nimbae , H. tubercula - tribution pattern of what he terms “para - tus ; savannah: H. nitidulus ). sylvicole” species, which occur at both for - As all natural habitats in the minute H. est edge and degraded forest habitats. nimbae range are under high anthropogenic Indeed some of these species such as A. dor - pressure, the current IuCN Red List classi - salis and H. fusciventris occur in both West fication “endangered” ( SChIøTz & R ödeL and Central Africa. however, many other 2004), is likely to call for reassessment West African forest and forest-related towards “Critically endangered”. Further species do not occur in Central Africa (see surveys will have to estimate the population

______(Abb. 3. Fortsetzung des Abbildungstextes der gegenüberliegenden Seite) man beachte die stark granulierte haut; b ‒ ventralansicht von H. nimbae , Kehle grünlich-braun mit kleiner, rundlicher und dunkel-gelbgrauer Kehldrüse; c ‒ dorsolateralansicht eines H. nitidulus Männchens aus dem Stadtgebiet von daloa (westliche zentrale elfenbeinküste), man beachte die kleinen Warzen auf der haut; d ‒ ventralansicht von H. nitidulus , Kehle gelb mit sehr großer gelber Kehldrüse; e ‒ dorsolateralansicht von H. tuberculatus , Männchen aus der Nähe des dja Waldes, Kamerun, man beachte die granulierte haut; f ‒ ventralansicht von H. tuberculatus , Kehle weiß und Kehldrüse grünlich-braun. Kouamé_etal_Roedel_etal_Rediscovery_hyperolius_nimbae_heRPeTozoA.qxd 08.08.2016 10:08 Seite 10

12 N’G. G. K ouAMé & N’G. e. A SSeMIAN & b. T ohé & P. J. A debA & G. G ouRèNe & M.-o. R ödeL

size as a basis for population monitoring. search for this species and argue for the sub - The authors thus urge further intensive sequent protection of its habitats.

ACKNoWLedGMeNTS

The authors are very much indebted to permit and the local population of Kouan-houlé, Conservation International in general, and RobIN d. dagbonpleu, zéalé and danipleu is acknowledged for MooRe in particular, for financial support, discussion their hospitality. Particular thanks go to PAuL Seu , and collaboration, and grateful to dAGo GNAKRI , elder of Kouan-houlé village for support and collabo - President of the JeAN LoRouGNoN Guédé university, ration, and the field assistants and local guides for their for providing the authorization to undertake this sur - invaluable help during field work. vey. The Prefect of danané is thanked for the research

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dATe oF SubMISSIoN: June 24, 2015 Corresponding editor: heinz Grillitsch

AuThoRS : N’Goran Germain KouAMé 1) , N’Guessan emmanuel ASSeMIAN 1) , blayda Tohé 2) , Patrick Joël AdebA 3) , Germain GouRèNe 2) & Mark-oliver RödeL (< Corresponding author < [email protected] >) 4) 1) Jean Lorougnon Guédé university, department of biology and Animal Physiology, daloa, bP 150, Côte d’Ivoire, < [email protected] >. 2) Nangui Abrogoua university, Laboratoire d’environnement et de biologie Aquatique, uFR-SGe, 02 bP 801, Abidjan 02, Côte d’Ivoire. 3) Centre Suisse de Recherche Scientifique, Abidjan, 01 bP 1303 Abidjan 01, Côte d’Ivoire. 4) Museum für Naturkunde, Leibniz Institute for evolution and biodiversity Science, Invalidenstrasse 43, 10115 berlin, Germany.