Description
Poyntonophrynus pachnodes is an African pygmy toad, with a snout vent length of around 28 - 33.7 mm in both males and females. The head length is approximately 30% of the snout vent length, and head width is about the same as or a little wider than head length. The head shape is triangular. The rostral tip is straight in dorsal, ventral and lateral views. The snout length is about 45% of the head length, and projects slightly beyond the upper jaw. The snout-nostril length is about 40% of the snout length. The naris is small, triangular, and directed dorsolaterally. Internarial distance is about two thirds of the interorbital distance. The canthus rostralis is short, and the loreal region is concave. The eye-nostril distance is slightly smaller than interorbital distance. The eye diameter is about 30% of the head width, and the interorbital distance is slightly larger than the eye diameter. The upper eyelid width is slightly smaller on average than the eye diameter. The eyes project laterally just beyond the eyelids and are approximately flush with the margins of the head in dorsal view. The pupil is large and ellipsoid (Ceriaco et al. 2018).

The forearm length is around 20% of the snout vent length. Finger IV is more than half the length of the forearm length. The relative length of fingers is III > I > IV = II. The finger tips are not expanded but rounded, with prominent double subarticular tubercle. The thigh length is about 36% of the snout vent length. The tibiofibular length is about 39% of the snout vent length. The tarsal fold and the webbing between manual digits is absent. Relative length of toes IV > III > II > I = V. Toe IV is around half the thigh length (if not a little longer). The toe tips are slightly expanded and the toes have prominent, single, and subarticular tubercles. The webbing between toes is vestigial, and doesn’t reach the first joint of the first phalanx. The skin of the venter has evenly scattered miniscule asperities while the skin of the gular region is smooth. The skin of the limbs, dorsal, and dorsolateral surface of the head and body have scattered tubercles that are larger on the dorsum. The parotid glands are inconspicuous, elliptical, and weakly elevated. They are placed dorsolaterally and extend from the posterior corner of the mouth to the level of the axilla (Ceriaco et al. 2018).

Poyntonophrynus pachnodes is a small-bodied bufonid that lacks tarsal folds, a characteristic that distinguishes itself from most bufonids in Angola (Mertensophryne and Poyntonophrynus are the only exceptions). Poyntonophrynus pachnodes is different from Mertensophryne in that P. pachnodes have inconspicuous parotoid glands unlike the pronounced parotoid glands of Mertensophryne. Poyntonophrynus pachnodes is distinguished from other members of the genus Poyntonophrynus in that P. pachnodes lacks a tympanum and columella (Ceriaco et al. 2018).

In life, the dorsal ground color is a dark brown with coppery to brown mottling. The toad also has dark brown blotches especially in anterior regions. Between the eyes (the scapular patch) is a whitish chevron, extending posteriorly. The iris is dark green with dark brown pupils. The snout is similar in color and pattern to the dorsum. The dorsal surface of the forelimbs and fingers III and IV is whitish with dark brown blotches, while the dorsal surface of fingers I and II is just white. There is a distinctive white blotch at the midbody. The dorsum and the lateral surface are dark brown and speckled with coppery markings that become faint towards the venter. The dorsal surface of the hind limbs (thighs and crus) is greyish white with distinctive dark brown markings and three dark blotches on the thigh, crus, and feet that touch when the legs flex. The base color of the dorsal foot is grayish, with scattered dark brown blotches. The region surrounding the cloaca is cream colored. The lateral most margin of the upper jaw is white, with brown markings posterior and anterior to the eye. The throat is immaculate white, and the ventral surface of the forearm and arm is whitish. The ventral surface of the hand and fingers is white. The venter is unpigmented and whitish, while the anterior part of the thighs and ventral crus is cream colored. The ventral side of the legs and the plantar surface of the pes are unpigmented and whitish in appearance (Ceriaco et al. 2018).

The whitish chevron extending between the eyes (scapular patch), is faded but visible in preservative. The dark green iris with a dark brown pupil is dark grey and pale gray in preservative, respectively (Ceriaco et al. 2018).

There is a decent amount of variation in size, with the snout vent length being from 28 - 33.7 mm. Not much variation in coloration has been observed (Ceriaco et al. 2018).

Distribution and Habitat

Country distribution from AmphibiaWeb's database: Angola

View distribution map in BerkeleyMapper.

At the time of the species species description, the species was only known to live in the Serra da Neve Inselberg in northern Namibe Province. Poyntonophrynus pachnodes were found on moist soil under rocks and leaves at dusk in a semi-open miombo forest area. The Serra da Neve is characterized by a sparse Miombo, dominated by trees from genera Julbernardia and Brachystegia, and shrubs from genera like Combretum or Annona (Ceriaco et al. 2018).

Life History, Abundance, Activity, and Special Behaviors
The species was found sympatrically with the frogs Sclerophrys gutturalis and Tomopterna tuberculosa, the lizards Agama schacki, Trachylepis sulcata, Chondrodactylus pulitzerae, Hemidactylus benguellensis, Pachydactylus angolensis, and Heliobolus lugubris, and the snake Hemirhagerrhis viperina (Ceriaco et al. 2018).

Comments
A Maximum Likelihood phylogenetic analysis was performed using the mitochondrial 16S gene and nuclear RAG-1. Poyntonophrynus pachnodes is most closely related to P. fenoulheti. However, the bootstrap support value is only 73% (Ceriaco et al. 2018).

Unlike most African anuran taxa, the species diversity of Poyntonophrynus is concentrated in arid southwestern Africa. Five species (P. damaranus, P. dombensis, P. grandisonae, P. hoeschi, and P. pachnodes) are strictly endemic to this region. This pattern of species distributions suggests that the origin of this group might have been in southwestern Africa (Ceriaco et al. 2018).

The genus Poyntonophrynus of African pygmy toads has long been considered contentious and confusing. There are only ten recognized species in this genus, and the area of Serra da Neve Inselberg is under researched (Ceriaco et al. 2018).

The specific epithet, “pachnodes” means “frosty”, which is a reference to both the cool climate where this species occurs and that Serra da Neve translates to “mountain of snow” (Ceriaco et al. 2018).

References

Ceriaco, L. M. P., Marques, M. P., Bandeira, S., Agarwal I., Stanley E. L., Bauer A. M., Heinicke M. P., Blackburn D. C. (2018). “A new earless species of Poyntonophrynus (Anura, Bufonidae) from the Serra da Neve Inselberg, Namibe Province, Angola”. ZooKeys 780: 109-136. [link]

Species Account Citation: AmphibiaWeb 2021 Poyntonophrynus pachnodes: Serra da Neve Pygmy Toad <https://amphibiaweb.org/species/8893> University of California, Berkeley, CA, USA. Accessed Nov 21, 2024.

Citation: AmphibiaWeb. 2024. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 21 Nov 2024.

AmphibiaWeb's policy on data use.