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| Pristimantis marmoratus (Boulenger, 1900)
in Kok, Dezfoulian, Means, Fouquet & Barrio-Amorós, 2018.
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Abstract
The frog Pristimantis marmoratus was originally described as Hylodes marmoratus by George A. Boulenger in 1900 based on a single specimen reported to have been collected at the foot of Mount Roraima in Guyana in 1898. We herein discuss the exact location of the type locality of P. marmoratus and provide a redescription of the species based on new material from Kaieteur National Park and from the slopes of Maringma-tepui in Guyana. We also describe the previously unknown vocalization and breeding ecology of the species, and conducted an exploratory molecular analysis of the phylogenetic relationships within the genus Pristimantis represented by the members of the “unistrigatus species group” in the Guiana Shield. Pristimantis marmoratus is a small-sized species mainly distinguished from its known Guiana Shield congeners by the combination of F I < II, SVL ≤ 20.4 in males, presence of vocal slits in males, granular/pustulate dorsal skin with well-developed scapular ridges, basal webbing between fingers, fringes on fingers and toes, crossed iris, diffuse yellow or pale green wash on groin, and absence of flashy colour on axillary/pre-axillary region. The advertisement call consists of a single note repeated at a rate of ca 11 calls/min with a dominant frequency ranging from 2756 to 3101 Hz. Pristimantis marmoratus is primarily arboreal, exclusively active at dusk, and probably restricted to the pristine rainforests of the Pantepui uplands and highlands, east of the Gran Sabana between ca 600 and 1800 m above sea level. Preliminary molecular analyses recovered Pristimantis marmoratus as sister to an unnamed species from the Eastern Guiana Shield. On grounds of the newly established distributional extent we suggest maintaining the IUCN conservation status as Least Concern.
Keywords: Anura; Guiana Shield; Pantepui; systematics; Terrarana
Superfamily Brachycephaloidea Günther, 1858
Family Craugastoridae Hedges, Duellman & Heinicke, 2008
Genus Pristimantis Jiménez de la Espada, 1870
Pristimantis marmoratus (Boulenger, 1900)
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| Fig. 4. Pristimantis marmoratus (Boulenger, 1900) (four individuals at the top) and P. pulvinatus (Rivero, 1968) (two individuals below). Intraspecific variation in dorsal colour pattern and sexual dimorphism in living specimens. Note: the subtle hint of green visible on the lower body and legs of some specimens of P. marmoratus is due to a reflection of the substrate (green leaf).
Photographs by Philippe J.R. Kok, except the uncollected P. pulvinatus, which is by César L. Barrio-Amorós.
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| Fig. 6. A. Guzmania cf. sphaeroidea (André) André ex Mez, an arboreal bromeliad species used as egg deposition site by Pristimantis marmoratus (Boulenger, 1900) in the Wokomung Massif. B. Egg clutch of Pristimantis marmoratus deposited on a leaf of the arboreal bromeliad Guzmania cf. sphaeroidea in the Wokomung Massif. C. Egg clutch of Anomaloglossus beebei (Noble, 1923) (white arrow) deposited in the phytotelmata of the same plant as in B. D. Dorsolateral view of IRSNB 17916, 11.3 mm SVL, a juvenile of P. marmoratus collected on the slopes of Maringma-tepui, Guyana.
Photographs A–C by D. Bruce Means, D by Philippe J.R. Kok.
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Natural history:
All specimens were found in undisturbed submontane or montane rainforest (Fig. 9), active on small
trees 50–300 cm above the ground, exclusively at dusk. Pristimantis marmoratus is not a common
species; only a few specimens have been found at each locality of occurrence. Males were found calling
(in June and November) upside down from mossy tree trunks of low diameter (< 10 cm) between 120
and 300 cm above the ground, except one male (IRSNB 14473), which was calling from the top of a
green leaf 50 cm above the ground. The “upside down” call posture is also found in the closely related
P. sp. 1 of Fouquet et al. (2013) (as recovered in our preliminary molecular phylogenetic analysis, see
below), and in P. espedeus and P. inguinalis.
In June 2012, which corresponds to the rainy season in the area, a cluster of four Pristimantis marmoratus
eggs (Fig. 6B) was found by one of us (DBM) attached to the inside part of a leaf of a bromeliad,
Guzmania cf. sphaeroidea (André) André ex Mez (Fig. 6A), 150 cm above the ground, on Mount
Kopinang, Wokomung Massif, near the top of Kamana Falls at about 1600 m elevation (04°59′58″
N, 59°52′49″ W). Molecular analyses confirmed conspecificity of these eggs with P. marmoratus
(Appendix 3). The large, white eggs did not have visibly developed embryos. After photographing and preserving the eggs, the small plant was investigated for inhabitants of the aquatic portion of the
phytotelmata. Immediately a small frog jumped out and disappeared into the deep ground litter, and
eggs and tadpoles of Anomaloglossus beebei (Noble, 1923) were found in the water of the phytotelmata
of the same small bromeliad and in the water of five other bromeliads nearby (egg/frog identifications
confirmed by molecular analyses). Pristimantis marmoratus and Anomaloglossus beebei thus share the
same bromeliad as an oviposition site on the Wokomung Massif (Fig. 6C). Other Pristimantis species
found in syntopy with P. marmoratus were P. dendrobatoides (above 1600 m elevation), P. jester (above
1300 m elevation), P. saltissimus (above 1000 m elevation), and P. pulvinatus (above 1000 m elevation).
Philippe J.R. Kok, Raheleh Dezfoulian, D. Bruce Means, Antoine Fouquet and César L. Barrio-Amorós. 2018. Amended Diagnosis and Redescription of Pristimantis marmoratus (Boulenger, 1900) (Amphibia: Craugastoridae), with A Description of Its Advertisement Call and Notes on Its Breeding Ecology and Phylogenetic Relationships. European Journal of Taxonomy. 397; 1–30. DOI: 10.5852/ejt.2018.397
