Research Article |
Corresponding author: Ana Sofia P.S. Reboleira ( sofiarebol@gmail.com ) Academic editor: Nesrine Akkari
© 2018 Ana Sofia P.S. Reboleira, Henrik Enghoff.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Reboleira ASPS, Enghoff H (2018) First continental troglobiont Cylindroiulus millipede (Diplopoda, Julida, Julidae). ZooKeys 795: 93-103. https://doi.org/10.3897/zookeys.795.27619
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The new species of millipede Cylindroiulus villumi is described from a cave in the Estremenho karst massif in central Portugal. It is the first cave-adapted species of its genus with a strict subterranean life-style in continental Europe, and is the fifth blind species of the genus. The new species is illustrated with photographs and diagrammatic drawings. It is tentatively placed in the purely Iberian Cylindroiulus perforatus-group. The differences between the new species and its relatives are discussed, as well as its adaptations to a subterranean life-style.
cave fauna, Julida , karst, Portugal, troglobiont
The genus Cylindroiulus Verhoeff, 1894 belongs to the Palaeartic family Julidae and has more than 100 species distributed in Macaronesia and Europe (
Cave-adapted species of Cylindroiulus species were only known from Madeira Island, whereas in continental Europe only two anophthalmic, but not troglobiont, species were known (
Nine species of Cylindroiulus are currently known from mainland Portugal: C. anglilectus Read, 2007, C. boreoibericus Read, 2007, C. britannicus (Verhoeff, 1891), C. caeruleocinctus (Wood, 1864), C. fenestratus Read, 1989, C. latestriatus (Curtis, 1845), C. perforatus Verhoeff, 1905, C. propinquus (Porat, 1870), and C. truncorum (Silvestri, 1896) (
Only very recently cave-adapted species of millipedes from Portugal have started to dig out of the dark and become known to science (
Sampling was performed by direct search in the cave Algar do Pena in Estremenho karst massif, central Portugal.
Specimens were examined under a binocular stereomicroscope Leica M165C, and measurements were made with the software Leica Application Suite V4.12. Gonopods, vulvae, legs and antennae were dissected and mounted on temporary slides in glycerine or lactic acid for study under light microscopy in a Leica DM2500 microscope. Measurements were made following the methodology described by
The type material is deposited in the collection of the Natural History Museum of Denmark, University of Copenhagen (
Holotype, male, Portugal, Estremenho karst massif, Algar do Pena Cave (Coordinates: 39°27'54.40"N, 8°48'25.24"W), ASPS Reboleira leg., 04 Nov 2014. Paratypes: Portugal, Estremenho karst massif, Algar do Pena Cave, ASPS Reboleira leg., 04 Nov 2014, 1 male, 2 females, 4 juvenile males and 1 juvenile; same data but 28 Mar 2018, 1 female and 1 juvenile.
A medium to small, blind, and unpigmented species of the Cylindroiulus perforatus-group. Anterior constriction pronounced and pilosity of the telson scarce. Differs from all other species in the group by the lack of eyes and by the shape of the gonopod mesomerite which is shorter than the promerite (>< C. fenestratus Read, 1989, C. perforatus Verhoeff, 1905, and C. ventanaea Read, 2007) and apically rounded (>< C. anglilectus Read, 2007). Further differs from other group members except C. anglilectus by the much shorter paracoxal process.
Male holotype: 37 podous + 1 apodous rings + telson; females up to 41 podous + 1 apodous rings + telson.
Body length up to 13 mm in females and 11.4 mm in males. Vertical body diameter (H): 0.9 mm (females) and 0.7 mm (males). Integument unpigmented (Figure
Gonopods (Figure
Cylindroiulus villumi sp. n. SEM of the male gonopod. A mesal view B lateral view C denticles on the anterior flagellum-conducting lamella of the solenomerite D pro- and mesomerite, anterior view E pro- and mesomerite, posterior view F opisthomerite, posterior view. Abbreviations: f: flagellum, fl: flagelliferous lobe of promerite, fp: finger-shapped projection of promerite, m: mesomerite, p: promerite, pc: lateral rim of paracoxite, pfl: posterior flagellum-conducting lamella, pp: paracoxal process, s: solenomerite, sc: sperm canal. Scale bars: 10 μm (A, B, D, E, F); 1 μm (C).
Vulvae (Figure
The new species is dedicated to the VILLUM Foundation, named after Villum Kann Rasmussen (1909–1993), as recognition for the generous support to research in natural sciences.
Cylindroiulus villumi sp. n. was discovered in the cave Algar do Pena, located in the Santo António plateau, the central sub-unit of the Estremenho karst massif in central Portugal. It was found inside a big piece of deadwood located at the base of the entrance pit to the cave, at a depth of 33 meters below the surface.
Algar do Pena is the largest underground chamber of Portugal. The temperature is very constant 13 ±1 °C and relative humidity close to saturation. It is a very oligotrophic cave where only a few cave-adapted species are recorded: the spider Nesticus lusitanicus Fage, 1931, the terrestrial isopod Trichoniscoides meridionalis Vandel, 1946, the springtail Onychiurus confugiens Gama, 1962; the dipluran Podocampa cf. fragiloides Silvestri, 1932; and the beetle Trechus gamae Reboleira & Serrano, 2009 (
The genus Cylindroiulus exhibits great morphological diversity concerning size, ocelli, number of segments, pigmentation, chaetotaxy, legs, accessory claws, and genital structures (
Two anophthalmic, subterranean-adapted species of Cylindroiulus, C. julesvernei and C. oromii, are known from caves of Madeira Island (
Cylindroiulus villumi sp. n. belongs to the nominal subgenus Aneuloboiulus Verhoeff, 1899 which is characterized by traits regarded as plesiomorphic (
The Algar do Pena Cave, where the new species was found, has been intensively sampled over the last decade, and only very recently this species was collected (
We acknowledge the Natural Park of Serra de Aire e Candeeiros for all kinds of logistic support in fieldwork, and Josh Jenkins Shaw for English revision of the manuscript. ASR is supported by a research grant (15471) from VILLUM FONDEN. All specimens were collected under permits of the Instituto de Conservação da Natureza e das Florestas.