Nectophrynoides luhomeroensis, 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 luhomeroensis sp. nov.

Suggested English common name.

Luhomero glandular tree toad.

Suggested Kiswahili common name.

Chura manundu wa mlima Luhomero.

Taxonomic remarks.

This species has previously been referred to as “ Nectophrynoides sp 06 ” by Liedtke et al. (2016).

Holotype.

An adult female specimen in the Natural History Museum, London, United Kingdom, BM 1983.6 ( KMH 2438 ) collected on the 25 th of October 1987 in Luhomero Mountains , Udzungwa Mountains National Park, Udzungwa Mountains, Iringa Region, Tanzania (approximate coordinates: – 7.78, 36.60) at 2500 m a. s. l. by Jan Kielland (Fig. 7 B ) .

Paratypes.

Series of seven subadult and one juvenile specimens in the Museo Tridentino di Scienze Naturali, Trento, Italy, MTSN 8311 , 8312, 8397, 8401, 8404, 8405, 8408 and 8409, collected on the 15 th of September 2004 in Luhomero Mountains , Udzungwa Mountains National Park, Udzungwa Mountains, Iringa Region, Tanzania ( –7.6965, 36.5722) at 2200 m a. s. l. by Michele Menegon .

Definition.

A member of the Nectophrynoides viviparus species complex based on overall body proportions, glandular limbs and large parotoid glands (Fig. 8 ), 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) distinct glandular masses on limbs; (2) medium body size (adult SUL 18.4–30.0 mm, mean 21.79 ± 3.77 mm); (3) expanded, rounded finger and toe tips with small discs; (4) parotoid gland rhomboid and slightly pointed posteriorly; (5) relative head width ( HW / SUL) 0.35–0.39; and (6) relative head length ( HL / SUL) 0.33–0.37.

Diagnosis.

Nectophrynoides luhomeroensis sp. nov. is easily distinguished from N. asperginis , N. cryptus , N. frontierei , N. laevis , N. laticeps , N. minutus , N. paulae , N. poyntoni , N. pseudotornieri , N. tornieri , N. vestergaardi and N. wendyae by having distinct glandular masses on limbs (versus indistinct or absent).

Nectophrynoides luhomeroensis sp. nov. is distinguishable from N. viviparus sensu stricto by its slightly smaller body size ( SUL 18.4–30.0 mm vs 18.8–37.2 mm), finger- and toe-tips more expanded and less slender and rounded, and parotoid glands rhomboid shaped, slightly pointed posteriorly (Fig. 9 B ) (vs fusiform shaped and rounded posteriorly [Fig. 9 A ]). For comparison to the other two new species described herein, refer to the diagnoses of the respective taxa, below.

Generalised description.

A medium-sized ( SUL: 30 mm) and robust Nectophrynoides with relatively short, muscular, and glandular limbs. The snout is triangular with a rounded tip and extends slightly beyond the upper lip. The canthus rostralis is slightly concave and flattened. 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 rhomboid shape (Fig. 9 B ). The body has irregular glandular patches scattered across the dorsal and lateral surfaces. The limbs with distinct 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 and alive specimens, the colouration and patterning are highly variable (Fig. 8 ). Preserved specimens have a cream to dark tawny brown ground colour with darker lateral flanks. The glandular masses are lighter tawny brown with caramel brown patterning or cream brown with little to no patterning.

Description of holotype.

BM 1983.6 ( KMH 2438 ), an adult female. There are large yolky eggs visible through the abdomen. All measurements are given in mm. A medium-sized and robust specimen ( SUL: 30.0, SVL: 30.7). Width of head ( HW: 10.7) almost equal to length of head ( HL: 10.9). Lower jaw rounded in dorsal and ventral profile with a very slightly blunted snout. Triangular snout slightly rounded anteriorly. In lateral profile, anterior end of snout level with bottom of eye, and inclines to upper jaw. Nostrils situated on either side of snout, at level of eye centre ( ND: 2.7), and clearly visible dorsally. Eyes relatively large and bulging in dorsal profile ( ED: 3.4). Distance between eye and naris ( END: 2.1) greater than distance between naris and tip of snout ( NSD: 1.8). In lateral profile, eye and dorsal orbit are continuous with anterior end of snout to scapular region. Canthus rostralis flattened and loreal region slightly 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: 1.1) roughly 1 / 3 of horizontal diameter of eye. Forelimbs muscular and relatively short. Forearm longer than humerus ( FOL: 8.0, HUL: 5.9), hand longest ( HAL: 9.4). Outer metacarpal tubercle length greater than width ( OMCL: 1.9, OMCW: 1.5), inner metacarpal tubercle shortest ( IMCL: 1.0). First and third fingertip almost equally expanded ( F 1 W: 0.9, F 3 W: 0.9). Hindlimbs muscular and relatively long. Tibia and thigh almost equal in length ( TIL: 12.3, THL: 12.7), roughly 1 / 3 longer than metatarsus ( ML: 8.0), foot longest ( FL: 14.0). Outer metatarsal tubercle length ( OMTL: 1.4) shorter than inner metatarsal tubercle ( IMTL: 2.1). First toe tip less expanded ( T 1 W: 0.8) than fourth toe tip ( T 4 W: 0.9). Hindlimbs more than twice as long as forelimbs ( HIL: 47.0, FORL: 23.3).

Skin texture smooth on glandular and non-glandular surfaces. Dorsal head and dorsum to cloacal region glandular with small pores. Dorsal orbit glandular with medium pores. Dorsum with irregular, large circular glandular masses. Dorsal surface of limbs with glandular masses. Humerus and femur with irregular glandular masses. Forearm, hands, tibia, metatarsus and feet have slightly swollen glandular masses with large pores. Parotoid glands paired and continuous with dorsal orbit. Parotoid glands with large pores and spongy texture. Parotoid glands situated from posterior to eye to scapular region above arm insertion. Parotoid glands rhomboid shaped, widest posterior to eye above angle of jaw and narrows to a slightly pointed shape in scapular region above arm insertion. Parotoid glands extend to lateral surface of tympanic region posterior to tympanum and narrows before arm insertion. Lateral surface of head consists of irregular patches of glandular and non-glandular skin. Posterior and inferior surface of tympanum to posterior end of eye with 10–15 small to medium glandular masses each with a small translucent spine. Flank with glandular patches. 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 tubercles that are raised from the skin. Hands and feet with rudimentary webbing. Feet slightly more webbed extending slightly beyond the first subarticular tubercles.

Dorsal ground colour tawny brown. Head and dorsum with caramel brown patches and spots. Dorsum and femur with tawny brown circular raised glandular bumps without patterning. Parotoid glands, limbs, glandular masses on limbs, hands, and feet tawny brown with caramel brown patches and spots. Femur dark tawny brown close to body and caramel towards knee. Flank ground colour caramel brown with few tawny brown spots toward dorsal margin and cream brown patterning toward ventral margin. Lateral head tawny brown with cream and caramel brown patches. Nostrils caramel brown. Abdomen, pectoral region and chin cream with tawny brown patches and spots. Ventral surface of hands and feet tawny brown with cream tubercles, fingers and toes. Ventral surface of limbs dark tawny brown. Femoral area caramel brown with tawny brown bumps.

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

Variation in the species.

Paratypes are smaller in body size and currently considered subadults. MTSN 8311 with dark tawny brown ground colour covering dorsal and lateral surfaces with tawny brown glands. MTSN 8405 and 8409 with cream ground colour and less distinct tympana. MTSN 8312 and 8405 with several white glandular patches and spots on lateral and dorsal surfaces. Sexual dimorphism was not observed in preserved material; females are expected to be larger than males as seen in congeners, but adult male specimens are needed to confirm this. Photographs and field notes of paratypes, and other individuals, highlight a strong variation in colouration and patterning (Fig. 8 ).

Preservation status.

The holotype is in good condition. The paratypes are generally in fair condition but are soft-fixed, making them fragile and difficult to work with. The condition of paratype MTSN 8312 has deteriorated since measurements were taken; it was then in fair condition but is now poorer.

Genetics.

Paratypes MTSN 8404 and 8405 have been successfully sampled and sequenced ( Liedtke et al. 2016). Nectophrynoides luhomeroensis 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. luhomeroensis sp. nov. was genetically distinct and identified as “ Nectophrynoides sp 06 ”. MTSN 8405 is at least 3.13 % genetically different in partial (ca. 550 bp) 16 S rRNA from all other Nectophrynoides , with the closest relative being N. uhehe sp. nov. (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 0–0.478 %.

Advertisement call.

Not recorded.

Etymology.

The species Nectophrynoides luhomeroensis sp. nov. is named after the type locality, which is Luhomero Mountains, within the Udzungwa Mountains National Park, Udzungwa Mountains, Iringa Region, Tanzania. The suggested common name is a reference to the distribution of this species across Luhomero Mountains in Udzungwa Mountains National Park, its glandular skin, and semi-arboreal lifestyle.

Habitat and life history.

The specimens were hand-caught at an elevation of 2200–2500 m a. s. l., and all specimens were found in a forest and grassland mosaic (Fig. 10 ). Paratypes were found on the moist montane forest floor along the forest edge. The presence of large yolky eggs in the holotype, BM 1983.6, suggest that this species is ovoviviparous, as in its congeners. Two more individuals ( JVL 1291 –1292) were collected recently by John Lyakurwa, Glory Summay, Christina Kibwe, Anifa John and Pius Mollel in November 2023 (Fig. 8 A, B ). The two individuals were caught on the ground during the day in a mosaic of shrubs and grasses at 1857 m a. s. l. on the western side of the Luhomero Mountains ~ 2 km from the Ruipa River ( –7.7563, 36.5855). The two individuals show strong resemblance both morphologically and genetically to the type specimens of Nectophrynoides luhomeroensis sp. nov. described above.

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 8. Intraspecific variation within Nectophrynoides luhomeroensis sp. nov. in life. A Adult JVL 1291; B adult JVL 1292; C subadult paratype MTSN 8312; D subadult paratype MTSN 8401. Photographs from Luhomero Mountains, Udzungwa Mountains; A, B by John V. Lyakurwa; C, D by Michele Menegon.

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 10. Habitat of Nectophrynoides luhomeroensis sp. nov. in Luhomero Mountains, Udzungwa Mountains National Park, Udzungwa Mountains. Photograph by Michele Menegon.