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| Stefania lathropae Kok, 2023 |
Abstract
Previous molecular analyses of the frog genus Stefania have shown that species boundaries in that group are often difficult to delineate when solely based on morphology. As a consequence, “taxonomically cryptic” species are not uncommon in the genus. Several highland Stefania species remain to be described, some potentially critically endangered due to their highly restricted geographic ranges. One case is the microendemic Stefania population from the summit of Murisipán-tepui, a poorly explored table-top mountain in the Los Testigos Massif, a small tepui mountain range located north to the much larger Chimantá Massif in southern Venezuela. That population, mistaken as S. satelles for two decades, was later reported as Stefania sp. 2 and belongs to the S. ginesi clade. The new species is phylogenetically distinct but phenotypically similar to S. satelles, a taxon restricted to its type-locality, i.e. the summit of Aprada-tepui in Venezuela. The new species is described based on morphology and cranial osteology. Molecular divergences with S. satelles are high (> 8%) in the barcoding fragment of 16S rRNA. Amended definitions for the two other described species in the S. ginesi clade (S. ginesi and S. satelles) are also provided. The new species should be listed as critically endangered according to IUCN criteria.
KEYWORDS: Cranial osteology, homoplasy, morphology, Pantepui, symplesiomorphy, systematics
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| Top left: aerial photograph of Murisipán-tepui, terra typica of Stefania lathropae sp. nov., taken facing southeast. Top right: type locality of Stefania lathropae sp. nov. along a lagoon on the southern summit of Murisipán-tepui. Bottom left: dorsolateral view of the holotype of Stefania lathropae sp. nov. in life (IRSNB 4208, male, 40.0 mm SVL). Bottom right: ventral view of the specimen freshly euthanized. Photos Philippe J.R. Kok. |
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| Macrohabitat and main colour pattern variation in Stefania lathropae sp. nov. Top left: deep crevice and typical vegetation on the southern summit of Murisipán-tepui. Top right: IRSNB 4211 (female; field number PK3654). Bottom left: IRSNB 4210 (female; field number PK3652). Bottom right: IRSNB 4209 (female; field number PK3656). Photos Philippe J.R. Kok. |
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| Phylogenetic relationships of the Stefania ginesi clade modified from Kok et al. (2016), based on 2,359 base pairs of nuclear and mitochondrial DNA (Bayesian statistical supports are provided at nodes, asterisks indicate values > 95%), and comparison of crania of S. ginesi, S. satelles, and Stefania lathropae sp. nov. in dorsal, lateral, and frontal views. Green circles highlight the condition of the contact between the maxillary process of the nasal and the maxilla. Blue arrows highlight the condition of the frontoparietal crests. Green arrows highlight the condition of the contact between the posterodorsal projection of the maxilla and the orbital/zygomatic ramus of the squamosal. Photos Philippe J.R. Kok. |
Stefania lathropae sp. nov.
Stefania satelles (in part) Señaris et al. 1997: 33–37
Stefania satelles (in part) Gorzula & Señaris 1999: 47
Stefania satelles (in part) McDiarmid & Donnelly 2005: 513, 521
Stefania satelles (in part) Kok et al. 2016: 6
Stefania sp. 2 Kok et al. 2017: 175–176
Definition and diagnosis: Stefania lathropae sp. nov. is characterized by the following morphological characters, the combination of which distinguishes it from all known congeners: 1) a small species of Stefania, max. SVL in preserved females 55.5 mm, 40.0 mm in preserved males; 2) head not distinctly longer than wide, about as wide as long; 3) canthus rostralis with a few low tubercles, angular, concave, canthal stripe present in life, usually tapering towards nostrils; 4) loreal region with a few low tubercles; 5) upper eyelid with a few low tubercles, none of them distinctly enlarged; 6) frontoparietal ridges present but low and barely visible (in life/preservative); 7) frontoparietal crests barely developed (on cranium); 8) constriction of the frontoparietal bones at the level of the anterior epiotic eminence; 9) low, sometimes extensive, exostosis on the cranium; 10) premaxillae slightly projecting posteriorly in lateral view; 11) posterodorsal projection of maxilla absent or highly reduced, not in contact with orbital/zygomatic ramus of squamosal; 12) maxillary process of the nasal not in contact with the maxilla; 13) horizontal length of tympanum more than 50% horizontal length of eye in both sexes; 14) vomerine teeth 3-8; 15) toes basally webbed, no significant difference in toe webbing between sexes; 16) dorsal skin (in life) tuberculate; 17) ventral skin (in life) granular; 18) absence of conspicuous outer tarsal tubercles (in life); 19) absence of multiple conspicuous dark brown bars on flanks and lips, presence of white dorsolateral stripes (in life); 20) in living adults, iris unicolour, copper, with extensive dark brown reticulations.
Etymology: The specific epithet lathropae is a noun in the genitive case, honouring Canadian herpetologist Amy Lathrop (born 1967). Amy was likely the first scientist to put her hands on several new Stefania species collected in the Pakaraima Mountains of Guyana, all later described with Ross D. MacCulloch, her colleague from the Royal Ontario Museum (Toronto, Canada).
Philippe J.R. Kok. 2023. Out of Sight, but Not Out of Mind: A Name for the Stefania (Anura: Hemiphractidae) from the Summit of Murisipán-tepui (Bolívar State, Venezuela). Journal of Vertebrate Biology. 72 (23024), 23024.1-16. DOI: 10.25225/jvb.23024
