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| Pleonaraius spelaeus Romero-Rincon & Ferreira, 2025 |
Abstract
A new troglobitic species of Dalodesmidae, Pleonaraius spelaeus n. sp., is described from Rolo Vergara Cave, Neuquén Province, Argentina. This species represents the fourth known troglobitic member of the family, the first troglobitic species of Dalodesmidae recorded in South America, and the first known troglobitic millipede from Argentina. Pleonaraius spelaeus n. sp. is distinguished from its congeners by the absence of cuticular pigmentation and a unique combination of gonopodal characters. Ecological notes, a key, and a distribution map of Pleonaraius species are also provided.
Keywords: cave; Diplopoda; key; new species; taxonomy
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| (A) Aereal view of the area where the cave in which Pleonaraius spelaeus n. sp. was found (yellow arrow indicates the cave entrance); (B) cave entrance at the bottom of the sinkhole; (C) cave conduct where the specimens were found and collected; (D) living male. |
Pleonaraius spelaeus n. sp.
Diagnosis. Based on the gonopodal conformation, the new species differs from its congeners by the following combination of characters: mb simple (vs. bifurcated and complex in P. omalonotus) and directed ventrad at its apex (vs. directed laterad in P. pachyskeles and P. omalonotus). lb simple with apex acuminate (vs. apex suberect in P. pachyskeles). Presence of pr as in P. pachyskeles (vs. absence in P. omalonotus).
Etymology. Spelaeus, adjective in the masculine gender. The epithet as a reference to the Latin word spelaeus, meaning “cave”.
Distribution. Only known from in Rolo Vergara Cave, municipality of Chos Malal, Neuquén Province, Argentina (Figure 5).
Juan Romero-Rincon and Rodrigo Lopes Ferreira. 2025. Into the Depths of Patagonia: The First Troglobitic Species of Pleonaraius Attems, 1898 (Polydesmida, Dalodesmidae) from Argentina. Arthropoda. 3(3), 13. DOI: doi.org/10.3390/arthropoda3030013 [3 September 2025]
