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| Pristimantis symptosus Köhler, Castillo-Urbina, Aguilar-Puntriano, Vences & Glaw, 2022 DOI: 10.3897/zse.98.84963 |
Abstract
The taxonomic status of the strabomantid frog species Pristimantis nebulosus (Henle, 1992), originating from the southern Cordillera Azul in central Peru, is investigated based on examination of the holotype and its comparison with freshly collected topotypic material. Following current standards, we provide a redescription of the holotype. It is in a rather poor state and exhibits certain damages and preservation artifacts, conditions that have hampered an allocation of this nominal taxon to any known living population of Pristimantis in the past. Our detailed specimen-to-specimen comparison provided morphological evidence for the conspecifity of the holotype and freshly collected topotypes. Molecular phylogenetic analysis, based on the mitochondrial 16S gene fragment places P. nebulosus in the P. conspicillatus species group, being closely related to P. bipunctatus and an undescribed candidate species from the Cordillera de Carpish. From both, P. nebulosus differs by considerable divergence in the 16S gene (p-distance 4.1–6.2%). Based on the specimens available, we provide an updated diagnosis for P. nebulosus, compare it to other species in the P. conspicillatus group and describe its advertisement call. In addition, we describe and name the closely related candidate species from the Cordillera de Carpish. It is sister to P. bipunctatus and P. nebulosus, but differs from both mainly by its tuberculate dorsal skin (versus shagreen) and divergence in the 16S gene (3.3–4.1%). We briefly discuss cryptic species diversity in the P. conspicillatus and P. danae species groups and provide justification for the description of a singleton species.
Key Words: Amphibia, bioacoustics, Cordillera Azul, Cordillera de Carpish, molecular genetics, morphology, Pristimantis conspicillatus species group, systematics, taxonomy
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| Topotypic Pristimantis nebulosus in life: Adult male (MUSM 40299) in a. dorsolateral, b. ventral, c. dorsal, and d. frontolateral views; adult male (MUSM 40298) in e. dorsolateral, f. ventral, and g. frontal views; h. Juvenile (MUSM 40326) in dorsolateral view (inset photo showing ventral view of same individual). Not to scale. |
Pristimantis nebulosus (Henle, 1992)
Distribution: So far, P. nebulosus is only known from its type locality in the southern Cordillera Azul, at the border of the Departamentos Huánuco and Ucayali. However, it is very likely that the species occupies a wider range, at least along the same elevational corridor within the Cordillera Azul. Possibly, there are additional records of this species represented by unidentified or misidentified specimens in scientific collections.
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Male holotype of Pristimantis symptosus sp. nov. (MUSM 40256, FGZC 6207) from the Cordillera de Carpish, 2360 m a.s.l., in life: a. Dorsolateral view of left body side; b. Dorsolateral view of right body side; c. Ventral view. Note tuberculate skin on dorsum, flanks and forearm. |
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| View of the forest along the road 18A close to the type locality of Pristimantis symptosus sp. nov. in the Cordillera de Carpish, Departamento Huánuco, Peru, at approximately 2450 m a.s.l. Photo taken on 4 November 2019. |
Pristimantis symptosus sp. nov.
Diagnosis: A medium-sized species of the Pristimantis conspicillatus species group (based on molecular relationships and morphological similarity), with 27.6 mm SVL in adult male, characterised by: (1) skin on dorsum tuberculate, with a pair of enlarged scapular warts; flanks tuberculate; throat smooth, venter weakly areolate; discoidal fold conspicuous; dorsolateral folds distinct, but low; dorsal folds absent; three prominent postrictal conical tubercles present; upper eyelid lacking tubercles and granules; posterior surfaces of thighs smooth; (2) tympanic membrane and annulus distinct, slightly higher than long, their length less than half of eye diameter; supratympanic fold long, prominent, almost straight, not covering upper tympanum or annulus; (3) head longer than wide; snout subacuminate in dorsal view, bluntly rounded in lateral profile; canthus rostralis straight in dorsal view, sharp in profile; (4) cranial crests absent; (5) dentigerous process of vomers prominent, elongate, oblique, situated posteromedial to choanae; (6) males with vocal slits, single subgular vocal sac, and nuptial asperities on dorsal surface of thenar tubercle; (7) hands with long and slender fingers, first finger equal in length to second; subarticular tubercles subconical, prominent; supernumerary tubercles absent; palmar tubercle bifid, flat; thenar tubercle prominent, elongated; terminal discs of inner two fingers enlarged and round, those of external fingers enlarged, ovate, about twice the width of digit proximal to disc; circumferential grooves conspicuous, ungual flap very slightly indented; lateral fringes on fingers absent; basal webbing between fingers absent; (8) ulnar tubercles absent; (9) tubercles on heel and tarsus absent, tarsal fold absent; (10) inner metatarsal tubercle ovate, prominent; outer metatarsal tubercle round, flat; supernumerary tubercles absent; (11) toes long and slender (FootL 54% SVL); narrow lateral fringes weakly expressed, trace of basal toe webbing present; toe V reaching distal level of penultimate subarticular tubercle of toe IV; toe V slightly longer than toe III; tips of toes rounded to slightly ovate, enlarged; circumferential grooves conspicuous; (12) in life, dorsal colouration brown to tan with dark brown chevrons and flecks on dorsum; dark brown bars on dorsal surfaces of arms and legs; dark brown interorbital bar; a pair of black spots, surrounding prominent conical scapular warts: broad black supratympanic stripe; black canthal stripe; belly cream; throat densely mottled with dark brown; ventral surfaces of thighs and shanks orange tan; posterior surface of thighs orange-brown with irregular cream spotting; plantar and palmar surfaces yellowish-brown, densely covered with dark brown mottling; iris copper, with black reticulation; posterior iris periphery pale blue; bones white; (13) advertisement call consisting of a single pulsed note of 132–186 ms duration, emitted at regular succession (see below).
Natural history: The forest at the type locality constitutes upper montane rainforest at the transition zone to cloud forest, growing on steep slopes (Fig. 10), with trees not exceeding 20 m height (Jiménez and Pacheco 2016). Males were calling from a low position in shrub vegetation along the road during a foggy night and light rain. The holotype was sitting on a leaf approximately 25 cm above the ground. Pristimantis sp. (lacrimosus group) and P. sp. (aff. rhabdocnemus) were found at nearby sites. Nothing else is known.
Distribution: Pristimantis symptosus is only known from its type locality and possibly endemic to the Cordillera de Carpish.
Etymology: The specific epithet is a Latinised adjective derived from the Greek σύμπτωση (symptosi) meaning ‘coincidence’. It refers to the fact that we only discovered the new species by coincidence on an unplanned return to the Cordillera de Carpish after forgetting part of our expedition gear there.
Jörn Köhler, Ernesto Castillo-Urbina, César Aguilar-Puntriano, Miguel Vences and Frank Glaw. 2022. Rediscovery, Redescription and Identity of Pristimantis nebulosus (Henle, 1992), and Description of A New Terrestrial-breeding Frog from Montane Rainforests of central Peru (Anura, Strabomantidae). Zoosystematics and Evolution. 98(2): 213-232. DOI: 10.3897/zse.98.84963
