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.
Highlights
Pristimantis marmoratus (Boulenger, 1900) is the oldest described Guiana Shield member of what has later been referred to as the “unistrigatus group”
We describe the call of P. marmoratus for the first time, report on its previously unknown breeding ecology, discuss an exploratory molecular analysis of the phylogenetic relationships within the genus Pristimantis represented by the members of the “unistrigatus species group” occurring in the Guiana Shield, and examine the IUCN Red List Category of the species
Kok et al (2012, suppl. info.) presented a molecular phylogenetic tree showing that two specimens of “P. pulvinatus” from La Escalera in Venezuela fall into two different clades, suggesting the occurrence of two morphologically similar species in that region
Summary
Pristimantis marmoratus (Boulenger, 1900) is the oldest described Guiana Shield member of what has later been referred to as the “unistrigatus group” (see Hedges et al 2008; Kok et al 2011; Kok 2013). MacCulloch et al (2010) mentioned that the species occurs in Amazonas State in Brazil, and described it as being “a terrestrial leaf-litter species found in tropical lowland and montane forest. Pristimantis marmoratus is currently reported as widespread in the Guiana Shield, occurring from Amazonian Venezuela to French Guiana (e.g., Rivero 1961; Lescure 1976; Lescure 1981; BarrioAmorós 1998; Lescure & Marty 2001; MacCulloch & Lathrop 2009; Avila-Pires et al 2010; Ouboter & Jairam 2012; Frost 2016). It breeds by direct development, but the egg deposition site is not known. The name marmoratus seems to have been occasionally used for any small brown, hard to identify Pristimantis in north-eastern South America, and the lack of comparative specimens from close to the type locality has prevented the improvement of the species diagnosis
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