Exploration into the hidden world of Mozambique ’ s sky island forests : new discoveries of reptiles and amphibians

We carried out a survey of reptiles and amphibians within Afromontane forest and woodland slopes of three inselbergs in northern Mozambique (Mount Mabu, Mount Namuli, and Mount Ribáuè). A total of 56 species (22 amphibians and 34 reptiles) were recorded during the current survey. Our findings substantially increase the number of herpetofaunal species recorded from these mountains (Mount Ribáuè 59%, Mount Mabu 37%, and Mount Namuli 11% of the total species), including one new country record and several putative new species. An updated checklist of the herpetofauna of these mountains is presented.


Introduction
Northern Mozambique (north of the Zambezi River and south of the Rovuma River) is biologically one of the most poorly known areas in Africa (see Tolley et al. 2016).This is a consequence of the limited infrastructure in the region as well as the protracted civil war (1977)(1978)(1979)(1980)(1981)(1982)(1983)(1984)(1985)(1986)(1987)(1988)(1989)(1990)(1991)(1992), which made travel and exploration problematic.In recent years, several biodiversity surveys have been conducted in northern Mozambique (e.g.Branch et al. 2005a& b, Timberlake et al. 2007, Bayliss 2008, Spottiswoode et al. 2008, Timberlake et al. 2009& 2012, Bayliss et al. 2010, peaks are found, but also by chains of smaller inselbergs extending eastwards towards the coast.These montane isolates form an important link between the better studied Eastern Arc Mountains (EAM) and the East African Coastal Forest (EACF).White (1983) classified the vegetation from Mts. Chiperone, Mabu, and Namuli as being associated with the East African Coastal Mosaic (EACM; type 16b).However, Timberlake et al. (2007Timberlake et al. ( , 2009Timberlake et al. ( , 2012) disregard White's classification and describe the vegetation from these mountains (especially at above 1600 m altitude) as more similar to the moist montane forests from the EAM.The presence of species from both, EAM and EACM, in Mts.Namuli (e.g.Timberlake et al. 2009) and Mabu (e.g.Timberlake et al. 2012) suggests that these mountains form a mosaic of biodiversity from two different ecoregions.
Findings from previous surveys suggest the Mozambican montane sky island forests contain high levels of biodiversity, particularly in terms of single site endemics (e.g.Ryan et al. 1999, Congdon et al. 2010, Portik et al. 2013b, Branch et al. 2014).In particular, high diversity is predicted in less vagile groups because these forests are isolated, and forest species are likely to have speciated in situ resulting in a suite of narrow endemics per mountain (Congdon et al. 2010, Branch et al. 2014, Bittencourt-Silva et al. 2016).The biological diversity of these poorly sampled montane forests is expected to be underestimated.This is particularly worrying as these, as yet undescribed, narrow endemics are at risk of extinction because of the substantial land use changes in the region.It is therefore critical that these poorly sampled forests receive attention towards documenting their biological diversity before they disappear.
Through targeted fieldwork, we explored three poorly known montane isolates (Mts.Mabu, Namuli, and Ribáuè), to document their herpetofaunal diversity.We conducted intensive surveys on these mountains across several habitats and over an altitudinal gradient searching for amphibians and reptiles.Although some herpetological surveys have been done recently on Mt.Namuli (Timberlake et al. 2009, Portik et al. 2013a, Farooq and Conradie 2015) and Mt.Mabu (Timberlake et al. 2012, Bayliss et al. 2014), Mt.Ribáuè has not been explored for its herpetofauna since 1964 (Blake 1965).The Ribáuè massif consists of two adjacent inselbergs covered with dry miombo and separated by a narrow valley (ca.3km) with miombo woodland.We only surveyed the eastern part of the massif known as Mt.M'pàluwé.We suspect that Blake (1965, p.37 & 38) previously surveyed the M'pàluwé section of Mt.Ribáuè and at that time only found seven species from the lower slopes and the forest was not visited.Poynton (1966) later reviewed the amphibians collected by Blake (1965) and recorded a total of ten amphibian species from M'pàluwé section of Mt.Ribáuè.Herein we present an annotated checklist of reptiles and amphibians from Mts. Mabu, Namuli, and M'pàluwé.Additionally, we provide a summary of all herpetological surveys carried out to date, on these sky island forests of northern Mozambique.

Study area
The study area comprises of two mountain blocks in the Zambezia province and one in the Nampula province in northern Mozambique (Fig. 1, Table 1).The landscape in this part of the country is scattered with inselbergs surrounded by miombo woodland forest.Some of these mountains are covered with dense moist forest (e.g.Mt.Chiperone and Mt.Mabu) whereas others are just exposed granitic rocks with isolated shrubs.
For both Mt.Mabu (Fig. 2A) and Mt.Namuli (Fig. 2B), the vegetation type at low and mid-elevation, i.e. below 800 m above sea level (asl), is dominated by cultivated areas and secondary forest, which gradually changes to denser and moister forests with the increase of elevation (>1000 m asl).On Mt.M'pàluwé (Fig. 2C), cultivated areas (called 'shamba' or 'machamba' locally in East Africa) dominate the lower part of the mountain, and at mid and high elevation the forest is drier -possibly due to progressive deforestation in the area as a result of the

Data collection
We conducted herpetofaunal surveys in the study area, between 15 November and 4 December 2014, using a combination of visual encounter survey and standard drift fences with pitfalls (each trap array consisted of 3 × 10 m long and 50 cm high fences positioned in a Y-shape with four pitfall traps at the ends and middle, and two one-way funnels per fence -only employed at Mts. Mabu and Namuli).Diurnal searches were done by actively looking for specific microhabitats including underneath rocks and logs.Nocturnal surveys were carried out with the use of headlamps or flashlights.Specimens were captured by hand, hook stick, noosing or net (e.g.tadpoles), and euthanized, according to ethically approved methods (Conroy et al. 2009), after which they were fixed in 4% buffered formalin for 48 hours and transferred to 70% alcohol for long-term storage in the herpetological collections of the Port Elizabeth Museum (PEM), South Africa, Museo delle Scienze (MUSE), Italy, and Natural History Museum of Maputo, Mozambique.Prior to formalin fixing DNA samples were collected (thigh muscle or liver), and stored in 99% ethanol for future genetic analysis.
Specimens were identified using field guides (Broadley 1990, Branch 1998, Channing 2001, Marais 2004, Du Preez and Carruthers 2009) and morphological comparison to material in the Port Elizabeth Museum.A number of specimens collected were difficult to assign to currently recognised species.In some species, e.g.Arthroleptis spp., Lygodactylus spp., specimens presented a variety of characters shared with known species and the present assignment is provisional pending ongoing studies.In some cases, further genetic and morphometric analyses will be carried out to confirm species identifications and will be presented elsewhere.We follow Frost (2016) for taxonomy of amphibians, Uetz and Hošek (2016) for reptiles, and were further updated where appropriate.In  internal fragmentation of the forest due to slash and burn clearing.The summits are characterised by bare granitic rocks with isolated patches of montane heath vegetation.Temporary streams are found in all three mountains but no permanent stream was found in Mt.M'pàluwé.
In northern Mozambique, the average temperature in the warmest months (December-February) varies between 20-25 ºC, and in the cooler months between 15-20 ºC.
addition to our survey findings the following literature was consulted to compile historical records for the study area: Poynton (1996), Branch and Ryan (2001), Timberlake et al. (2009, 2012), Portik et al. (2013a), andFarooq andConradie (2015).To compile species accounts, specimens were measured for body size: snout-urostyle length (SUL) for anurans and snout-vent length (SVL) and tail length (TL) for reptiles.Measurements were taken using a digital calliper to the nearest 0.1 mm.

Results and discussion
A total of 27 amphibian species representing 10 families and 14 genera (Table 2), and 45 reptile species (19 snakes, 25 lizards, one tortoise) representing 12 families and 31 genera (Table 3) have been recorded from the three mountains.The current survey contributed numerous additional amphibian and reptile species to the checklist of northern Mozambique inselbergs (13 for Mt.Mabu, five for Mt.Namuli and 19 for Mt.M'pàluwé).
During the current survey we recorded four species of reptiles endemic to Mozambique (Nadzikambia baylissi, Rhampholeon maspictus, Rhampholeon tilburyi, and Lygodactylus regulus), and four putative new species of Nothophryne (Bittencourt-Silva et al. 2016).We also documented one new country record, the snake Duberria shirana (see account below).Acanthocercus atricollis was omitted from the final checklist of Mt.Namuli.It was erroneously reported by Portik et al. (2013a) to be recorded from Mt. Namuli, although they only listed specimens collected from Serra Jeci, more than 300 km to the northwest of Mt.Namuli.This record was followed in error by Farooq and Conradie (2015).Portik et al. (2013a) also reported a few species from the low-lying Gurué village and surroundings (Breviceps mossambicus, Sclerophrys gutturalis, S. pusilla, Lygodactylus capensis, Naja melanoleuca, and Boaedon capensis) and included them in their checklist for the inselbergs.As the focus of this study is to record the herpetological diversity of the sky island forests we omitted the above records, including Agama mossambica (current study -see species account).SUL).Comments: Specimens were collected from moist leaf litter in closed-canopy forest (Fig. 3A).Some individuals were found sitting on low vegetation (<1 m).All mature males exhibit extended third finger and dark throat.
Comments: Found in both dry transitional miombo woodland and montane forest (Fig. 3C).This species is very similar to A. francei, which seems to be more abundant in these forests.One feature that helps to separate these two species is the hind limbs, being shorter in A. stenodactylus.In Mt.Mabu it was common on the forest floor, and at Mt. M'pàluwé it was found in moist leaf litter at lower elevations (Fig. 3B).Mature males exhibit extended third finger and dark throat.

Leptopelis broadleyi Poynton, 1985
Material.Mt.M'pàluwé (PEM A11367, male, 30.9 mm SUL).Comments: Sub-adult male specimen was collected from mid-elevation slopes while calling from low vegetation.This species is part of the L. argenteus group.Some authors regard this as a valid species (Poynton andBroadley 1987, Schiøtz 1999 M'pàluwé area.We only found the latter.

Pipidae
Xenopus laevis (Daudin, 1802) Material.Mt.Mabu (PEM A11291, female, 45.8 mm SUL).Comments: One specimen was collected from a low-elevation stream below an old hydroelectricity dam.Poynton and Broadley (1991) report no records of X. laevis for northern Mozambique, but do report it from southern Malawi.The Malawi population has been confirmed by molecular analyses to be X.laevis (Furman et al. 2015).
On the other hand, X. muelleri is common in lowland Mozambique.Ohler and Frétey (2014) reported the first record of X. petersii for Mozambique.Based on a low number of plaques (17 plaques around the eye and 20 from eye to vent) their assignment of the specimen to X. petersii is doubtful and most likely represents X. laevis (which shows the same level of variation in plaque counts).

Ptychadena cf. porosissima (Steindachner, 19867)
Material.Mt.Namuli (PEM A11351, female, 31.8 mm SUL).Comments: Collected from grassland on Muretha Plateau.This specimen is tentatively identified as Ptychadena cf.porosissima using the key provided in Poynton and Broadley (1985).The specimen lacks the characteristic tibial white line.Comments: Specimens were collected both during the day and at night from rocky outcrops in water seepages (Fig. 3E, 3F).Historically, Nothophryne has only been reported from two localities: Mt.Mulanje, Malawi (type locality) and Mt.M'pàluwé in Mozambique (Poynton 1962& 1966, Blake 1965), both higher than 1200 m asl.Timberlake et al. (2009) were the first to report this species from Mt. Namuli.Some calls similar to Nothophryne were heard from the summit of Mt.Mabu, but no frog was visually located to confirm the species occurrence in this mountain.Genetic analyses suggest a cryptic diversity in this genus (Bittencourt-Silva et al. 2016) and additional work is underway to update its taxonomy.Based on its small distribution these nominotypical species is listed as Endangered (Mazibuko and Poynton 2004).Referring to that the undescribed species will receive similar red list status.Comments: Part of the Strongylopus faciatus group that has seen two newly described species in recent years (Channing andDavenport 2002, Clarke andPoynton 2005).Mercurio (2011) assign Strongylopus from Mt. Mulanje to S. merumontanus.While Poynton (2004) don't list them from southern Malawi and rather refer to them as S. fuelleborni.The phylogenetic affinities of our newly sampled population are unknown and additional work will be necessary to clarify its taxonomic status.For now, we assign them to S. fuelleborni.Adult specimens and tadpoles were found along a high-elevation stream in a patch of Afromontane forest at Mt. Mabu (Fig. 3G).Specimens from Mt. Namuli were collected along marshy areas in montane grassland.
The specimen (probably a young female) measures 210 mm total length, 6.3 mm body width and has 142 pri-mary annuli.The olive-brown dorsal colouration of the preserved specimen is dorsally restricted and the venter is light yellowish (pinkish in life), agreeing with the description of Nussbaum (1985).This new record represents the southernmost distribution of Scolecomorphus kirkii, and for all African caecilians.Branch (2004) reported the first ever caecilian record for Mozambique from dry transitional miombo vegetation at the edge of Serra Mecula, while Farooq and Conradie (2015) recorded a second record from Mt. Namuli.monotypic genus endemic to Mt. Mulanje (Broadley 1965a), but recently Branch and Tolley (2010) described a second species from Mt. Mabu.We here report the first record for Mt.Namuli (Fig. 4A).Ribuáuè insolates forests (Fig. 4C).Based on the isola-tion of all the northern Mozambique inselbergs and high genetic differences reported by Branch et al. (2014), it is highly plausible that this new population represents an undescribed species.Most similar to R. tilburyi in external morphology.
Comments: Collected from the lower slopes of Mt.M'pàluwé where they were found in abundance running on rocky slopes.Previously, collected from Mt. M'pàluwé [=Ribáuè] by Blake (1965), which formed part of the type series of this species (Broadley 1965b).This species is now regarded as widespread in northern Mozambique (Broadley 1965b, Branch et al. 2005) and southern Tanzania (Broadley 1995).
Comments: Collected at Mt. Mabu from rock surface and under tree bark in low to mid-elevation.At Mt. M'pàluwé specimens were collected in sympatry with H. platycephalus on derelict buildings of the Oasis Water Camp.

Lygodactylus cf. rex Broadley, 1963
Material.Mt.Mabu (PEM R21147, male, 48.1 mm SVL; PEM R21148, male, 42.1 mm SVL).Comments: Specimens were collected from tree trunks in transitional miombo at lower slopes (Fig. 4D).These large geckos are morphologically similar to L. rex from Mt. Mulanje in that they share the large size of typical L. rex (up to 55 SVL : Portik et al. 2013b), the mental scale is very shallow with lateral slits, and the conspicuous ocellus (spot) above the shoulder.Given the high level of genetic diversity in montane species of this genus (Portik et al. 2013b, Travers et al. 2014)

Scincidae
Melanoseps cf.ater (Günther, 1873) Material.Mt.Mabu (PEM R21126, 93 mm SVL, 28.6 mm TL; PEM R21127, 121 SVL, 39.9 mm TL).Comments: Broadley et al. (2006) assigned the northern Mozambique specimens to M. loveridgei, while specimens from southern Malawi are referred to as M. ater.We used the key from Broadley et al. (2006) to identify the specimens based on number mid-body scale rows (24).Timberlake et al. (2012) were the first to report this species from Mt. Mabu and this was only the second record for this genus in Mozambique.Farooq and Conradie (2015) recorded M. cf.loveridgei from Mt. Namuli.This identification was tentative, as material got lost in a motor vehicle accident and could not be examined.Based on the close proximity to Mt. Mabu the Mt.Namuli record should be regarded as M. cf.ater.

Trachylepis maculilabris (Gray, 1845)
Material.Mt.Mabu (PEM R21150, female, 88.6 mm SVL).Comments: One adult female was collected from a transition woodland.Branch et al. (2005) were the first to record this species from northern Mozambique and indicate, based on material used from coastal northern Mozambique (Carranza et al. 2001)   We follow Portik et al. (2013a) and refer to this specimen as capensis, rather than fuliginosus, based on general colouration.

Gonionotophis capensis (Smith, 1847)
Material.Mt.Mabu (PEM R21152, male, 965 mm SVL + 160 mm TL; PEM R21153, female, 993 mm SVL + 143 mm TL).Comments: Two specimens were collected on the same night (15 November 2014) from the same locality near a stream at the base of Mt.Mabu.It is possible that the male was following the female, as they were collected minutes apart.

Conclusions
We have found eight putative new species through field identification, added additional species known from northern inselbergs (13 species to Mt. Mabu, five species to Mt. Namuli, and 19 species to Mt. M'pàluwé), and one new country record.Additional analyses are necessary, including barcoding and phylogenetic analyses, to determine whether these mountains are exceptionally high in species richness.We now know there are at least 30-40 species of reptiles and amphibians on each of these sky islands, many of which are montane endemics.Although the state of knowledge is growing for Mt.Mabu and Mt.Namuli and can be considered to be relatively well sampled, it is clear that Mt.Ribáuè isolates requires more work given the brevity of our survey.In addition, several other sky islands in the area have received little or no attention in terms of the herpetofaunal survey (e.g.Mt.Inago and Mt.Chiperone).The present collection is essentially a preliminary assessment of amphibian and reptile diversity in the region and does not account for seasonal variation in activity of herpetofauna.Future surveys that are more comprehensive in space and over time should considerably increase our understanding of the regional diversity, endemism, and richness of these inselbergs.Although the state of biodiversity knowledge has grown for Mts.Mabu and Namuli, there is an urgent need for a clear understanding of the nature of threats, and mitigation measures that will directly improve protection of habitat.At Mt. Ribàué additional surveys are imperative, given the comparatively limited exploration on that mountain coupled with the apparent high rate of forest clearing.Overall, the sky islands of Mozambique clearly require additional surveys to quantify species richness and endemism for a broad range of taxonomic groups.Ultimately, a better understanding of the threats to biodiversity will allow for prioritisation of conservation interventions.

Table 1 .
Localities surveyed in northern Mozambique.

Table 2 .
Updated species lists for amphibians based on historical records as well as data from the current surveys.Parentheses in the totals given denote the number of new species recorded during the current surveys.Literature records are indicated with L and new records with N.

Table 3 .
Updated species lists for reptiles based on historical records as well as data from the current surveys.Parentheses in the totals given denote the number of new species recorded during the current surveys.Literature records are indicated with L and new records with N.
Laurent, 1954 Material.Mt.M'pàluwé (PEM A11368, female, 31.7 mm SUL).Comments: Found on dry leaf litter at low slopes of Mt.M'pàluwé.ments:ChanningandBaptista(2013) revised southern African river frogs and restrict A. angolensis to Angola and assign southern populations of A. angolensis to either A. quecketti or A. poyntoni.Channing et al. (2016) re-instated A. delalandii as a senior synonym of A. quecketti.More recently, Larson et al. (2016) identified several well-supported cryptic lineages of river frogs previously assigned to A. angolensis in the Albertine Rift region, which refer that further cryptic diversity can be expected in East Africa.The phylogenetic affinities of our newly sampled population are unknown and additional work will be necessary to clarify its taxonomic status.Commonly found at both low and high elevation in forested streams (Fig.3D).

cf. fuelleborni (Nieden, 1911)
Collected at the lower slopes on the rocky outcrops of both Mt.Namuli and Mt.M'pàluwé.Both males brightly coloured, while females are dull in overall colouration.
Agama mossambica Peters, 1854Material.Mt.Namuli (PEM R21114, female, 95.7 mm SVL).Comments: One specimen collected in Gurúè town.This record was omitted from our final checklist of the inselbergs, as it was collected from the low lying town (see Results and Discussion).PEM R21190, female, 80.1 mm SVL).Comments: Collected from canopy forest, in Afromontane forest above 600 m asl.Historically, Nadzikambia was considered a

Branch, Bayliss & Tolley, 2014
This newly described species of pygmy chameleon was collected from Mt. Namuli at both the Ukalini forest and the forest patches on the Muretha Plateau (Fig.4B).Considerable morphological differences, e.g.well-developed dorsal crenulations, continues and well developed temporal ridge, and reduced rostral and supraocular processes, were observed between the two sub-populations of Mt.Namuli.Specimens were found in Afromontane forest above 1900 m asl.This species is restricted to Mt. Mabu.
SVL; PEM R21210, male, 37.5 mm SVL).Comments: This is the first record of a pygmy chameleon from Mt.
this could either represent an extension of its distribution or a new species.For that reason, we tentatively assign it to L. rex.One individual collected from a tree trunk in a newly cleared shamba at the top of Mt.M'pàluwé at night.Specimen from Mt. M'pàluwé differs from L. cf.rex from Mt. Mabu, and L. regulus from Mt Namuli in that they lack the conspicuous ocellus above the shoulder.It closely resembles L. angularis in general throat markings and that the mental is entire and not split with shallow lateral slits as in the L. rex group.

Colubridae Dispholidus typus (Smith, 1828)
Spawls et al. (2002))of a cryptic species in the north of Mozambique.Our record is the first for Mt.Mabu and fills a large gap between the northern (Lipumbulo floodplain) and the Zambezi Valley records.Records from north of the Zambezi remains scattered to only a handful of records, e.g.Lipumbulo floodplain, Moebase, and Moma(Branch et al. 2005).Portik et al. (2013a)also recorded this species from Lichinga further north andBranch et al. (2005)recorded them from Niassa Game Reserve.Specimens collected from forest floor or in low growing trees along streams (Fig.4F).Except for Mt.M'pàluwé specimen, which was collected from low growing scrubs in the forest, far from any water.Based on the identification key provided bySpawls et al. (2002)the Mozambique species keys out as D. shrevei shrevei, from which it differs on ventral and subcaudal counts.First collected in 2008(Timberlake et  al. 2012, Bayliss et al. 2014)from Mt.Mabu.Specimen collected from Mt. Mabu has 10 black spots anterior on the dorsum, while the Mt.M'pàluwé specimen has uniform lime-green colouration.The Mt. Mabu specimen was collected from an overhanging tree along a well vegetated low-elevation stream at night, while the Mt.M'pàluwé was collected around a water tank at the Oasis Water Camp.