Nectophrynoides saliensis, Thrane & Lyakurwa & Liedtke & Menegon & Petzold & Loader & Scherz, 2025

Thrane, Christian, Lyakurwa, John V., Liedtke, H. Christoph, Menegon, Michele, Petzold, Alice, Loader, Simon P. & Scherz, Mark D., 2025, Museomics and integrative taxonomy reveal three new species of glandular viviparous tree toads (Nectophrynoides) in Tanzania’s Eastern Arc Mountains (Anura: Bufonidae), Vertebrate Zoology 75, pp. 459-485 : 459-485

Nectophrynoides saliensis sp. nov.

Suggested English common name.

Mahenge glandular tree toad.

Suggested Kiswahili common name.

Chura manundu wa Mahenge.

Taxonomic remarks.

This species has previously been referred to as “ Nectophrynoides sp 13 ” by Liedtke et al. (2016).

Holotype.

An adult presumably female specimen in the Museo Tridentino di Scienze Naturali, Trento, Italy, MUSE 13758 ( KMH 26644 ) collected December 2005 in Sali F. R . , Mahenge Mountains, Morogoro Region, Tanzania (approximate coordinates: – 8.93, 36.65) at 1050–1500 m a. s. l. by Frontier-Tanzania ( Menegon et al. 2011 a) (Fig. 7 D ) .

Paratypes.

Series of adults and subadults: MUSE 13754 ( KMH 26637 ), 13755 ( KMH 26638 ), 13756 ( KMH 26639 ), 13757 ( KMH 26641 ) and 13759 ( KMH 26998 ), all with the same collection data as the holotype.

Definition.

A member of the Nectophrynoides viviparus species complex based on overall body proportions, glandular limbs and large parotoid glands (Fig. 7 D ), as well as genetic affinities based on mitochondrial markers (Fig. 1 ). This species is characterised by the unique combination of the following set of characters: (1) indistinct glandular masses on limbs; (2) medium body size (adult SUL 20.8–34.3 mm, mean 26.30 ± 5.02 mm); (3) weakly expanded rounded finger and toe tips with minute discs; (4) parotoid gland spearhead shaped; (5) relative head width ( HW / SUL) 0.40–0.43; and (6) relative head length ( HL / SUL) 0.37–0.40.

Diagnosis.

Nectophrynoides saliensis sp. nov. is easily distinguished from N. asperginis , N. cryptus , N. frontierei , N. laevis , N. pseudotornieri , N. wendyae by having a distinct tympanum.

The smooth dorsal surface of Nectophrynoides saliensis sp. nov. is covered with glandular patches and warts, indistinct glandular masses on limbs, and the parotoid glands form a large distinct spearhead shape, which distinguishes it from N. laticeps , N. minutus , N. tornieri , N. paulae , N. poyntoni , N. vestergaardi .

Nectophrynoides saliensis sp. nov. is distinguishable from N. viviparus sensu stricto by having indistinct limb glands. The finger- and toe-tip expansion of N. saliensis sp. nov. are also more expanded than N. viviparus sensu stricto, which has more slender and rounded fingers. The parotoid glands are elongated, and spearhead shaped, narrowing to a thin acuminate shape posteriorly (Fig. 9 D ), whereas the parotoid of N. viviparus sensu stricto are fusiform shaped and rounded posteriorly (Fig. 9 A ).

Nectophrynoides saliensis sp. nov. is distinguished from Nectophrynoides luhomeroensis by lacking distinct limb glands (vs distinct), differently shaped parotoid glands (spearhead vs rhomboid [Fig. 9 D and Fig. 9 B , respectively]), larger relative head size ( HL / SUL 0.37–0.40 vs 0.33–0.37, and HW / SUL 0.40–0.43 vs 0.35–0.39), and from N. uhehe by a much smaller maximum body size ( SUL 34.3 mm vs 52.5 mm), by lacking distinct limb glands (vs distinct), and differently shaped parotoid glands (spearhead vs kidney [Fig. 9 D and Fig. 9 C , respectively]).

Generalised description.

A medium-sized ( SUL: 34.3 mm) and robust Nectophrynoides with relatively short, muscular and slightly glandular limbs. The snout shape is triangular with a rounded tip and extending slightly beyond the upper lip. The canthus rostralis is angular. The tympanum is distinct. The parotoid glands are distinct and continuous with the dorsal orbits. The parotoid glands extend from the posterior end of the eyes to above the arm insertion in the scapular region forming a rough spearhead shape (Fig. 9 D ). The body has small irregular glandular bumps and patches scattered across the dorsal and lateral surfaces. The limbs with indistinct glandular masses. The length of the foot is greater than the length of the tibia. The hands and feet with rudimentary webbing. The finger and toe-tips are expanded and rounded.

In preserved specimens, the colouration and patterning are variable. The ground colour is very dark tawny brown with ash grey glandular bumps. The glandular masses on limbs and the parotoid glands are ash grey with dark tawny brown patterning.

Description of holotype.

MUSE 13758 ( KMH 26644 ), presumably female adult. The specimen has a mid-ventral incision along the body. All measurements are given in mm. A medium-sized and robust specimen ( SUL: 34.3, SVL: 35.0). Width of head ( HW: 13.6) almost equal to length of head ( HL: 13.1). Lower jaw rounded in dorsal and ventral profile with slightly flattened and blunted snout. Wide triangular snout slightly rounded anteriorly. In lateral profile, anterior end of snout is level with bottom of eye. Nostrils situated on either side of snout, at level of eye centre ( ND: 2.3), and clearly visible dorsally. Eyes relatively large and bulging in dorsal profile ( ED: 3.6). Distance between eye and naris ( END: 3.0) greater than distance between naris and tip of snout ( NSD: 1.5). In lateral profile, eye and dorsal orbit continuous with anterior end of snout to scapular region. Canthus rostralis angular and loreal region concave from top of canthus rostralis to edge of upper jaw. Canthus rostralis visible in dorsal profile. Tympanum and tympanic annulus distinct and rounded. Horizontal diameter of tympanum ( TYMP: 1.4) less than half of horizontal diameter of eye. Forelimbs muscular and relatively short. Forearm longer than humerus ( FOL: 9.3, HUL: 6.8), hand longest ( HAL: 11.4). Outer metacarpal tubercle length equal to width ( OMCL: 2.0, OMCW: 2.0), length of inner metacarpal tubercle shortest ( IMCL: 1.5). First fingertip less expanded ( F 1 W: 0.9) than third fingertip ( F 3 W: 1.0). Hindlimbs muscular and relatively long. Tibia longer than thigh and metatarsus ( TIL: 17.8, THL: 17.0, ML: 10.3), foot longest ( FL: 18.9). Outer metatarsal tubercle length ( OMTL: 1.7) shorter than inner metatarsal tubercle ( IMTL: 2.6). First and fourth toe tip equally expanded ( T 1 W: 1.0, T 4 W: 1.0). Hindlimbs more than twice as long as forelimbs ( HIL: 64.1, FORL: 27.5).

Skin texture smooth on glandular and non-glandular surfaces. Dorsal head glandular with small pores. Dorsal orbits glandular with medium pores. Dorsum with small, irregular, raised glandular bumps. Front and hind limbs with indistinct glandular masses. Humerus and femur have small irregular glandular bumps. Forearm, hands, tibia, metatarsus and feet have indistinct glandular masses with large pores. Parotoid glands paired and continuous with dorsal orbits. Parotoid glands with medium pores. Parotoid glands situated from posterior to eye to scapular region above arm insertion. Parotoid glands rough spearhead shaped, widest posterior to eye above angle of jaw and tympanum, narrowing to an acuminate shape in scapular region above arm insertion. Parotoid glands extend to lateral surfaces of tympanic region posterior to tympanum and become irregular patches of glandular and non-glandular skin. Lateral head consists of irregular patches of glandular and non-glandular skin. Posterior and inferior surface of tympanum to posterior end of eye has 10–15 small to medium glandular masses each with a small translucent spine. Flank with small, irregular, raised glandular bumps. Ventral surfaces non-glandular except for femoral area with small, raised bumps. Fingers and toes slender with slightly expanded and rounded digit tips. Hands and feet with distinct, raised tubercles and rudimentary webbing. Feet slightly more webbed extending slightly beyond the first subarticular tubercles.

Dorsal ground colour very dark tawny brown. Dorsum and flank with many ash grey, raised, glandular bumps. Dorsal head with a large ash grey glandular patch with very dark tawny brown spots. Limbs, hands and feet with ash grey glandular patches, spots and stripes. Tympanic region tawny brown with ash grey glandular patches. Lateral head ash grey. Canthus rostralis and nostrils tawny brown. Dorsal orbits bluish ash grey. Ventral surface of limbs, abdomen and chin cream. Pectoral regions cream with caramel brown patches. Ventral surfaces of hands and feet caramel brown with cream tubercles, fingers and toes. Femoral area caramel brown with cream bumps.

No photographs or field notes describing colouration of holotype in life are currently known.

Variation in the species.

MUSE 13755 tawny brown dorsal ground colour with very dark tawny brown patterning on dorsal and ventral surfaces. MUSE 13755 has a less distinct tympanum. MUSE 13755 and 13759 have very slightly pointed snout tips. Sexual dimorphism was not observed in preserved material, but females are expected to be larger than males, like congeners.

Preservation status.

The holotype and paratypes are in fair condition but show evidence of previous exposure to unsuitable preservation. The specimens are shrunken, stiff, and partially desiccated, with dried finger- and toe tips.

Genetics.

Holotype MUSE 13758 and paratypes MUSE 13754 , 13755, 13757 and 13759 have been successfully sampled and sequenced ( Liedtke et al. 2016). Nectophrynoides saliensis sp. nov. is genetically distinct according to Liedtke et al. (2016), who used species delimiting approaches (specifically bGYMC) to examine current bufonid diversity against undescribed diversity. In their analysis, N. saliensis sp. nov. was genetically distinct and identified as “ Nectophrynoides sp 13 ”. MUSE 13758 is 3.11 % genetically different in partial (ca. 550 bp) 16 S rRNA from all other Nectophrynoides , with the closest relative being Nectophrynoides viviparus sensu stricto (see Table 3 ). This is rather at the inter-specific level than the infra-specific (population) level; the intra-specific distance between sequenced specimens is 0–0.718 %.

Advertisement call.

Not recorded.

Etymology.

The species Nectophrynoides saliensis sp. nov. is named after the location where the species was discovered, which is Sali F. R. in Mahenge Mountains, Tanzania. The suggested common name is a reference to the distribution of this species in the Mahenge Mountains, its glandular skin, and semi-arboreal lifestyle.

Habitat and life history.

There is very limited knowledge of habitat, ecology, and behaviour of this species. The specimens were discovered by Frontier-Tanzania in a dense, low canopy submontane forest near open canopy wetlands in the northern inaccessible forests of Sali F. R. (Fig. 13 ). A paper published based on the work by Frontier-Tanzania in Mahenge Mountains describes Sali F. R. as a landscape consisting of miombo woodlands at lower elevation, submontane and montane forests, dry grassland, wetlands and large rocky outcrops ( Menegon et al. 2011 a). Little is known about the reproductive biology of this species but the presence of large, developed embryos visible through the abdomen of paratype MUSE 13757 suggests that the species is ovoviviparous, as in its congeners.

Figures

Figure 1. Maximum likelihood phylogeny of glandular tree toads inferred from the three mitochondrial markers (Nectophrynoides viviparus complex). ModelFinder recovered three partitions of the data (Partition 1: 12 S, 16 S - TPM 2 u, Partition 2: COI _ p 1, COI _ p 2 - HKY, Partition 3: COI _ p 3 - TIM 2). Branch supports refer to bootstrap values, and branch lengths represent the number of nucleotide substitutions per site (see scale bar). Nectophrynoides species not part of the N. viviparus complex are shown in grey, and type material for which sequence information was obtained via museomics are shown in orange. Heatmap inset shows mean uncorrected 16 S genetic pairwise distances.

Figure 7. Comparative photographs of lectotype and holotypes. For each specimen, dorsal (left), lateral (centre), and ventral (right) views are shown. A Lectotype of Nectophrynoides viviparus sensu stricto (ZMB 21775); B holotype of N. luhomeroensis sp. nov. (BM 1983.6; KMH 2438); C holotype of N. uhehe sp. nov. (ZMUC R 131391; M 000044); D holotype of N. saliensis sp. nov. (MUSE 13758; KMH 26644). Scale bar: 10 mm.

Figure 9. Comparative illustration of parotoid glands of Nectophrynoides viviparus sensu stricto and the new species described herein, shown in dorsal view. A Paralectotype of Nectophrynoides viviparus sensu stricto (ZMB 84909); B paratype of N. luhomeroensis sp. nov. (MTSN 8312); C paratype of N. uhehe sp. nov. (ZMUC H 01955; R 970529); D holotype of N. saliensis sp. nov. (MUSE 13758; KMH 26644). Illustrations by Simon P. Loader.

Figure 13. Habitat of Nectophrynoides saliensis sp. nov. in Sali F. R., Mahenge Mountains. Photograph by Michele Menegon.