Two new species of Polydesmus Latreille, 1802/1803 from northern Spain with reinstatements of two species, and a key to the Iberian Polydesmus species (Diplopoda, Polydesmida, Polydesmidae)

Abstract Polydesmus biscayensissp. nov. and P. asturiensissp. nov. are described and figured based on material housed in the Museo Nacional de Ciencias Naturales in Madrid. The specimens were collected in six localities in the Asturias and Cantabria provinces, including four caves. In addition, Polydesmus haroi Mauriès & Vicente, 1977 and Polydesmus racovitzai Brolemann, 1910 are transferred from Propolydesmus Verhoeff, 1895 to Polydesmus Latreille, 1802/1803 after examining the gonopod morphology. A key to the Iberian Polydesmus species is presented.

Two new species of Polydesmus are described below, based on material housed in the Museo Nacional de Ciencias Naturales, Madrid. They were collected in northern Spain, from five localities in Asturias and one in Cantabria (Fig. 1).

Materials and methods
Preserved specimens were examined in 70 % ethanol using a Leica MZ Apo stereomicroscope. When making Scanning Electron Micrographs (SEM), structures such as gonopods and antennae were gently mounted on stubs using sticky tabs and the airdried stubs were sputter coated with gold. A Zeiss Supra 55 UP field emission scan-ning electron microscope used for observation and photographs. Photographs of tergal structures were made with an Olympus SC 50 camera mounted on an Olympus SZX 10 stereomicroscope using Olympus software. Morphological terminology for this studied group follows Djursvoll (2008). Nonetheless, some names of the gonopod structures are specified here. Endomere, the main gonopod part which brings the seminal groove to the solenophore -surrounded with the pulvillus. The same part is identical to "solenomere" and "femorite", occasionally used by other authors. Acropodite, a tooth that originates from the distal part of endomere, always distal to the solenophore/pulvillus. The same part is identical to "distofemoral process" occasionally used by other authors. Several acropodites may occur. Exomere, gonopod part that originates basally on endomere, usually lateral and sometimes with a marked sulcus, usually with outgrowth of several teeth (processes). Abbreviations: exm = exomere, endm = endomere, t = tooth on exomere, a = acropodite.
The type material is stored in the Museo Nacional de Ciencias Naturales, Madrid (MNCN Etymology. Named after the Bay of Biscay. Diagnostic characters. Differs from other Polydesmus species in having a well-developed twisted endomere together with the acropodites -a1 close to the solenophore and a hooked acropodite a2 at the distalmost end, a long, slender and curly exomere, together with the presence of a ventrolateral tooth t1 directed proximal just after main curvature point, and the placement of the distal t2 tooth distally. Description. With 20 body rings, total length 10-12 mm. Coloration whitish to pale yellow (longtime ethanol-preserved specimens only). Collum ovoid, narrower than head and the subsequent rectangular metatergum 2 which is approximately as wide as head, head > collum > metatergum 2 (Fig. 2). Antennae comparatively long, not surpassing body ring 3, antennomere 6 almost clavate and slightly longer than 4 and 5, 4 = 5 < 6 >> 7, with dorsoparabasal sensory knob on antennomere 7, sensillar area on antennomere 5-7 (Fig. 3). Metaterga rectangular, paraterga projected laterad, tergal sculpture (tuberculation) in three transverse rows, third row barely visible in metaterga 2-4. Setae clavi-to bacilliform, caudolateral part of paraterga with distinct keels especially from metarterga 4 and back. Ozopore located slightly inside caudolateral margin. Three distinct lateromarginal incisions in paratergum 2-4, four incisions on 5, incisions less distinct more posteriorly. Epiproct pointed apically. Male legs distinctly swollen, sphaerotrichomes present. Legs 1.5-2.0 times as long as midbody height, with single dorsal macrosetae on tibia.
Female with marked apophysis (tubercle) supporting the orifice of the gonopore on second coxae (Fig. 16). Epigynal ridge poorly modified but with pin-shaped median process, with crevice inside. Vulva relatively short, e.g., from lateral view less than 2× as long as high.

Discussion
Enghoff and Golovatch (2003) redefined the small and solely southwestern European genus Propolydesmus Verhoeff, 1895, adding 12 species formerly placed in Polydesmus and adding one previously recognized Propolydesmus in synonymy, thus increasing the number of included species from four to 15. Consequently, the range of Propolydesmus has greatly expanded eastwards in Europe. Many of the species had been placed in subgenus Hormobrachium (Attems, 1940), that was synonymized with Polydesmus (s. str.) by Djursvoll et al. (2001). Later Djursvoll (2008) transferred Propolydesmus mauriesi (Vicente, 1979) to Schizomeritius Verhoeff, 1931. Without a species-level revision and a comprehensive analysis, the attributions of some of the species to Propolydesmus by Enghoff and Golovatch (2003) may be premature, as several of the species seem to have their affinities elsewhere. Both Verhoeff (1895) and Djursvoll et al. (2001) in Propolydesmus diagnoses emphasized the character with particularly reduced endomere, while Enghoff and Golovatch (2003) stated "a relatively to very short/stout gonopod femorite". This may have opened for the more extensive interpretation. However, Enghoff and Golovatch added for Propolydesmus, the important gonopodal character -presence of a seminal cavity, found in Propolydesmus laevidentatus (Loksa, 1967), in contrast to Verhoeff (1895) and Djursvoll et. al. (2001). In particular, Propolydesmus laevidentatus, as illustrated by Enghoff and Golovatch (2003: 83, figs 4-7) differs from Polydesmus by having a strongly reduced endomere, and a slightly curved exomere with numerous teeth (Figs 18, 19). In addition, a looped seminal groove that does not extend onto the endomere branch, also in accordance with the type species Propolydesmus pectiniger (Verhoeff, 1893).