Two centipedes new to the fauna of La Palma (Canary Islands, Spain) and notes on the Lithobiomorpha of the island (Chilopoda, Myriapoda)

Abstract Recent collecting on the island of La Palma has yielded two new records, Lithobius (Monotarsobius) crassipesoides and Lithobius (Lithobius) melanops, the former also being new to the Canary Islands and is recorded for the first time after its recent description. We additionally provide species records for the lithobiomorph species of the island, with new locality data and a distribution map based on recent and literature records. We update the checklist of the lithobiomorph species of the Canaries and document all the newly collected species.

La Palma is among the most volcanically active and one of the smallest of the Canary Islands. Located at north-western most part of the Archipelago, it is dominated by the Caldera de Taburiente in the North and the Cumbre Vieja in the South, with the ridge Cumbre Nueva connecting both parts. During a recent field trip on the island, we were able to collect a number of centipedes, mainly of the order Lithobiomorpha, among which two new records for the island, Lithobius ( L.) melanops Newport, 1845 and Lithobius ( M.) crassipesoides Voigtländer, Iorio, Decker & Spelda, 2017, the latter also being recorded for the first time in the Canary Islands.
Additional localities are provided for the hitherto known species and a distribution map, based on older and recent records, is presented to illustrate the occurrences of the different species on the island.

Material and methods
All specimens were collected by hand or obtained by sifting in October 2017 and kept in 96% ethanol in the collections of the Naturhistorisches Museum Wien. Multifocus images were obtained with a Nikon SMZ25 stereomicroscope equipped with a Nikon DS-F2.5 camera using NIS-Elements Microscope Imaging Software with an Extended Depth of Focus (EDF) patch. Some images were edited in Photoshop CS6 and figures assembled in Adobe InDesign CS6. The map was produced in QGIS 2.18.19, using the coordinate reference system WGS84 and topographic data obtained from USGS (

Remarks:
The record of L. crassipes from La Palma was first provided by Eason and Enghoff (1992), based on adult specimens from Roque de Los Muchachos at 2300 m. The same authors also mention a number of differences observed between the specimens from the Canaries with their European counterparts.  Distribution: Known to be endemic to the island La Palma. Hitherto recorded from Cubo de la Galga, Los Tilos and Cumbre Nueva (Eason 1985;Eason and Enghoff 1992 (Bonato et al. 2016). In the Canaries, the species is known from Lanzarote; Gran Canaria; Tenerife and La Palma (Eason and Enghoff 1992).

Lithobius (Lithobius) lusitanus Verhoeff, 1925
Remarks: Eason and Enghoff (1992) gave the first record of the species from La Palma, based on an unspecified number of specimens from Cumbre Nueva.    Distribution: Known to occur only in Tenerife, L. melanops is here recorded for the first time on La Palma. The species occurrence on the island is most probably due to anthropogenic activities.

Discussion
With the two new records of L. melanops and L. crassipesoides, the lithobiomorph fauna of La Palma presently includes 6 species, all belonging to the genus Lithobius and, among which, two are from the subgenus Monotarsobius. The finding of L. crassipesoides is particularly interesting as this represents the first record of the species from the Canaries and as a whole after its recent description (Voigtländer et al. 2017). These same authors provided a detailed molecular and morphological comparison of the species with its close congener and widespread species L. crassipes, based on specimens from Spain, France and Germany, respectively. Perhaps among the most striking morphological differences are a DaP spine starting from the leg-pair 12, a narrower middle coxosternal notch and somewhat more slender female gonopods (Voigtländer et al. 2017, fig. 16). These characters have been verified on the female specimen newly found in La Palma (Fig. 3). This begs the question whether the previous findings of L. crassipes from La Palma and in the Canary Islands is rather referring to L. crassipesoides.
The second new record is represented by L. melanops, a widespread species known from Africa, Europe and northern America (see Bonato et al. 2016 for detailed distribution records). L. melanops was hitherto recorded exclusively from Tenerife in the Canary Islands (Latzel 1895;Eason 1985). Eason (1985) further mentioned that the specimens he then studied agree with the description provided by Serra (1984). Latzel (1895) mentioned in his original description of the species from Tenerife (as Lithobius orotavae Latzel, 1895) an additional paramedian pair of prosternal teeth but these were not present on the specimens from La Palma (Fig. 4b).
The species of the genus Lithobius are mainly distributed in the north-eastern part of La Palma (Fig. 6). This sector has probably been more explored for invertebrates in general due to the interesting and varied types of habitats ranging from dry pine forests to wet mixed forests (see Fig. 7) and perhaps is more suitable for myriapods in comparison with the dry south-western part.

Figure 6.
Distribution map illustrating the occurrences of Lithobius species on La Palma based on new and literature records (Eason 1985;Eason and Enghoff 1992).

Figure 7.
Example of habitats accommodating Lithobius species; A, B. Pine forest along the road to Roque de los Muchachos; C, D. Laurel Forest, near a waterfall Los Tilos.
Two centipedes new to the fauna of La Palma (Canary Islands, Spain) and ... 9