A new Oromia species for Canarian underground biodiversity 1 Oromia orahan (Curculionidae, Molytinae), a new subterranean species for the Canarian underground biodiversity

A new blind weevil belonging to the genus Oromia Alonso-Zarazaga, 1987 is described, being found in the underground of the laurel forest of La Gomera (Canary Islands). Individuals were mainly collected in a colluvial mesocavernous shallow substratum, besides one specimen collected in the deep humic layer of soil. This new species has clear diagnostic differences from the other Oromia species. The number of taxa in this endemic Canarian genus increases to four species, easily identified using the key provided in this article. New data on other Canarian subterranean weevils are also provided.

Oromia species are eyeless, with elongated and rather flattened bodies, slightly depigmented, all these being typical characters of weevils with a subterranean life style (Morrone and Hlaváč 2017). Oromia species are probably rhizophagous, they are usually found on or very close to roots hanging from the ceiling in lava tubes, and in the MSS they have always been collected in places with subsoil rich in roots (Machado and López 2015).
Several individuals of an unknown Oromia species were discovered in the laurel forest of the Canarian island of La Gomera, and the purpose of the present work is to provide its description.

Sampling and imaging
The first individual of this new species of Oromia was discovered while sifting soil under a dead laurel stump in La Gomera laurel forest, within Garajonay National Park. Thereafter, we started a systematic sampling of the MSS in another location of this forest using subterranean traps especially designed for this environment (López and Oromí 2010). Traps were revised each three months, being baited indistinctly with liver or blue cheese. After two years of continuous trapping, we captured several individuals of this new species.
After the study, the dirt deposited on the individuals was removed with a small paintbrush and warm water with dish-washing soap. For a comparative morphological analysis with respect to the other Oromia species, several specimens of O. hephaestos, O. aguiari and O. thoracica from the collections of the authors were used. Examination, dissection, measurements, and drawings were completed with the use of a Carl Zeiss Citoval 2 stereomicroscope with an ocular micrometer. Photographs were taken under magnification using a CanonPowershot A650 attached to a Zeiss Stemi 2000 stereomicroscope and processed with the program Zerene Stacker (V. 1.04, Zerene Systems, LLC., Richland, WA), combining them into a single image using pmax and dmap methods.

Depositories
The material examined is deposited in the following collections:
Rostrum (average length 1.1 mm) as long as pronotum and 4× as long as wide at apex. Rostrum dorsally parallel-sided, coarsely punctured and carinulated in basal half; apical half with a median keel and two pairs of lateral keels, all well-defined; each pair of lateral keels join at the end of metarostrum forming an elongated, narrow hexagon through mesorostrum, continuing from here as a single keel along prorostrum. Prorostrum smooth, punctured, with apical setae. In lateral view, metarostrum convex. Ventrally, rostrum with three carinae, median carina thin and weak, slightly defined or barely visible beyond the basal half, lateral carinae more robust.
Antennae with short bristles, inserted in apical third of rostral length. Scape smooth in the basal half, punctated and microreticulated surface in the apical half, 7.3× as long as its maximum width and 1.45× as long as funicule. First funicular antennomere obconical, 2.25× as long as wide; second obconical, 1.5× as long as wide, narrower than the first and half as long; funicular antennomeres 3 to 5 isodiametric, 5 to 7 slightly transverse. Club globose sub-rhombic, 2× as long as wide and as long as the last 5-6 funicular antennomeres.
Pronotum 1.1× as long as wide, anterior margin 0.66× as wide as posterior; with three strong keels from anterior to posterior margin, median one straight and two paramedian ones sinuous, and in addition two strong lateral keels; in dorsal view, these lateral keels form a sub-trapezoidal pronotum outline, rounded angles, widest at level of posterior third; margins between these angles variable, from straight to slightly sinuous. Surface mat, with well-defined punctation on keels and edges, microreticulate intervals and some microsetae on keels. Prosternum with three longitudinal keels that cut transverse prosternal furrow, leaving two well-defined foveae.
Scutellum not visible. Pterothorax with elytra oblong, elongated, lacking humeral calli, almost parallelsided with slight concavity towards middle; with microreticulate surface, punctation and pubescence similar to that on pronotum; 2.7× as long as pronotum and 1.78× as long as wide. Interstriae from barely defined to strongly costiform: odd interstriae strongly costiform, 7 th forming marginal border without reaching apical callus; even interstriae barely defined, resulting in two rows of superficial punctures conforming striae between each interstria; 8 th interstria not defined in the lateral declivity, 9 th slightly careniform. Metasternum 3× as wide as long, with dense, deep, rugose punctation.
Abdomen with two first ventrites with shallower sparse punctation, disc of both depressed. Fifth ventrite with punctation similar to first two and 2.1× as wide as long.
Legs with dense coarse punctation, covered with setae. Procoxae separated by distance of 0.0125× of their diameter, 1.6× of distance from anterior margin of pronotum and 1.5× of distance from posterior margin of pronotum. Mesocoxae separated by distance of 0.5× their diameter. Pro-, meso-and metafemora respectively 4.7×, 4.4× and 6× as long as their maximum width. Protibiae 5.8× as long as wide at apex (without counting uncus), almost straight, with external edge irregularly denticulate, and with dense strip of setae in a slight inner apical concavity. Meso-and metatibiae 5.4× and 6.9×, respectively, as long as their maximum width. First metatarsomere 1.36× as long as wide; second transverse, 0.66× as long as wide; third strongly bilobed, transverse, 0.87× as long as wide; onychium 3.6× as long as wide, 2/3 of its length projected from the third metatarsomere.
Aedeagus. Penis symmetric in dorsal view, parallel-sided and with the apex briefly pointed ( Fig. 2A); dorsal plate strongly chitinised; clearly curved in lateral view, with acute apex and small callus; internal sac with densely arranged teeth in two longitudinal bands occupying the apical two thirds of tube. Spiculum gastrale robust and bowed with highly asymmetric arms (Fig. 2B). Tegmen with macrosetae, short manubrium and short, subparallel, blunt-tipped parameroid lobes (Fig. 2C).
Note. All collected individuals of Oromia orahan have the body total o partially covered by mud or dirt due to their subterranean life style, being often difficult to observe details of the tegument (scales, pores, keels, etc). The appearance of the individuals is very different when this dirt is removed (Fig. 3), a common feature in all Typoderini (Hlaváč, comm. pers.).
Differential diagnosis. Oromia orahan from La Gomera has outstanding morphological differences with respect to O. hephaestos from Tenerife and O. thoracica from Gran Canaria, regarding to size and shape of pronotum among other characters (see key to the species). However, O. orahan is close to O. aguiari from Tenerife, from which it differs by its longer and less curved rostrum, thicker scape, the shape of pronotum due the marginal keels (Fig. 4A), deeper general punctation, and the 8 th interstria not marked in the lateral declivity.
Other differences related to the reproductive structures are: i) the aedeagus of O. orahan has parallel sides while in O. aguiari they are concave (Fig. 4B); ii) the manubrium of the spiculum ventrale of O. orahan has a short arm forking into two longer arms forming an obtuse angle, while in O. aguiari the manubrium is divided into two arms arising directly from the plate of the spiculum ventrale forming an acute angle (Fig. 4C); iii) the tegmen of O. aguiari has subtriangular parameroid lobes whereas in O. orahan the lobes are subparallel, short and with blunt tips (Fig. 4D).
Etymology. Specific name in apposition of Orahan, who was considered as the supreme god, creator of everything, by the aboriginal people of La Gomera.
Habitat and distribution. The known distribution of Oromia orahan sp. nov. is restricted to Garajonay National Park, a protected area of approximately 40 km 2 located on the central mountainous region of La Gomera. This National Park includes one of the best representations of laurel forest in the Canary Islands. This type of vegetation was thought to be a relict flora from South Europe and North Africa, extinct during the Tertiary period due to the effects of glaciations and the desertification in these areas (Cronk 1992;Médail and Quézel 1999;Nakamura et al. 2000), although this has been recently questioned (Kondraskov et al. 2015). The laurel forest is a humid wood, in which approximately 15 broad-leaved, evergreen tree species from 10 different families form the canopy (e.g. genera Laurus, Ilex, Persea, Picconia). This forest constitutes the ecosystem with the highest levels of arthropod diversity within Macaronesia (Fernández-Palacios et al. 2017). Consequently, it is an interesting habitat for the exploration of the subterranean biodiversity. For this reason, we selected two localities in the Garajonay National Park to study the subterranean fauna using two different methods.
In Monte de Los Acebiños we sifted leaf litter and soil under the stump of a dead laurel, and at other sites we washed soil following the first steps of the technique described by Arribas et al. (2016). Besides one individual of O. orahan sp. nov. collected with the first method, in this locality we found other interesting subterranean coleopteran species such as the weevils Laparocerus oromii Machado, 2008 andTorneuma aphroditae (Germann &Stüben, 2006), and the ground beetle Lymnastis gaudini gomerae Franz, 1965. In Reventón Oscuro we installed four subterranean traps following López and Oromí (2010) in the MSS on a steep slope originated by colluviation at the base of rocky cliffs, but probably also increased by more recent stony debris slipping downslope during the construction of an old forest road. To install the traps, places with 100% canopy cover were selected, which render a permanent penumbra to the surface and humidity to the underground layer. This locality was especially rich in subterranean All populations of Oromia orahan sp. nov. are located inside a natural protected area, well preserved, at least at the epigean level. So we can assume that this species is under no threat at the moment. However, in recent years we have detected an alarming correlation between the increase of the non-native polydesmid millipede Brachydesmus sp. in the subterranean habitats of the National Park and a considerable decrease in captures of native endogean invertebrates in subterranean traps. Specific studies on the effect of this polydesmid on the subterranean communities are necessary, to establish the real conservation status of this new species.

New data on Canarian subterranean weevils
Besides the discovery of new species like Oromia orahan, the active searching of the fauna in the different subterranean habitats of the Canary Islands, especially in the subsurface layers, is providing new distributional data for some poorly known spe-cies which are worth to be recorded. The databases of biodiversity are very useful for a research, management, education and communication (Borges et al. 2010), so the publication of new data about the precise distribution of the species is of great importance to increase and update the information of these databases. Given the difficulty of studying the subterranean fauna, these databases usually have little information about underground species, so it is especially necessary the recording of such data. In this way, the management of the territory carried out by the governments using these databases will take into account the underground species, a type of fauna especially sensitive to the transformation of the habitats.

Subfamily Cossoninae Schoenherr, 1825
Barretonus  (García et al. 2019), B. daute from Tenerife was considered to have a few ommatidia, but this is a wrong statement that has to be amended in that description as well as in Table 2. Actually, all species of Barretonus are eyeless, since also the statement by Folwaczny (1972) that B. minor Folwaczny, 1972 andB. major Folwaczny, 1972 had also highly reduced eyes was wrong, which has been confirmed after the revision of the types by Peter Stüben (pers. comm.). Recently, we have collected some individuals of B. auarita on a new locality situated between other two already known, which indicates that this species must be well distributed along the eastern and northern coast of the island. The speciose genus Laparocerus includes one species from South Morocco and 221 taxa endemic either to Madeira or the Canary Islands (Machado, 2018), several of them having adapted to the different habitats of the underground as lava tubes, the MSS and the soil (Machado 2018). The prospection of MSS and soil in La Gomera has provided new locations for L. oromii on this island, one of them being the first location reported for this species outside Garajonay National Park. García, 1998 New record. La Palma. Mazo, Lomo Oscuro (28°34'51.83"N, 17°46'53.59"W, 536 m a.s.l.), 1 ex, 11 January 2015; 1 ex. 17 January 2017, R. García leg. (RGB).

Laparocerus dacilae
This other species of subterranean Laparocerus is endemic to the southern half of La Palma island, where it has always been collected in caves. We provide a new locality in which some specimens have been collected under big stones. This small, apparently edaphobiont species is only known from lava tubes of the southern half of La Palma. The cave where it has been recently found enlarges its distribution towards northwest, close to the limit of the geologically older northern half of the island.