Entomoculia (Stenotyphlus) vulcanica, Hernando & López, 2024

Hernando, Carles & Lopez, Heriberto, 2024, A new subterranean species of Entomoculia Croissandeau, 1891 from the Canary Islands, Spain (Coleoptera, Staphylinidae, Leptotyphlinae), Contributions to Entomology 74 (1), pp. 1-6 : 1

Entomoculia (Stenotyphlus) vulcanica sp. nov.

Figs 1-6

Type locality.

Caldera de Los Marteles, MSS, UTM 28R 448100/3092038, Gran Canaria, Canary Islands, Spain.

Type material.

Holotype ♂ CANARY ISLANDS: "GRAN CANARIA / Caldera de Los Marteles MSS-2 / UTM 28R 448100/3092038 / 22-05-2021, H. López leg." (IPNA). Paratypes 1 ♀: "GRAN CANARIA / Caldera de Los Marteles MSS-1 / UTM 28R 448100/3092038 / 07-12-2009, H. López leg." (CHC); 1 ♂: "GRAN CANARIA / Los Majaletes MSS-2 / UTM 28R 450511/3091134 / 26-12-2010. H. López leg." (CHC); 1 ♂: "GRAN CANARIA / Caldera de Los Marteles MSS-1 / UTM 28R 448100/3092038 / 26-03-2016, H. López leg." (IPNA).

Description.

Male. Habitus as in Fig. 1 . Body length: 1.7 mm. Colour: entirely depigmented (reddish-brown). Apterous and anophthalmous. Labrum tridentate (Fig. 2 ). Antennae with ten antennomeres (Fig. 1 ). Metatrochanter unarmed, without denticles or spiniform process. Morphology of aedeagus characteristic, sternal plate long and narrow, with the external margin serrated, endophallus with two accessory pieces: one dorsal, forked at apical end and another central and stiletto-shaped.

Head elongated, slightly wider than the pronotum, almost parallel-sided, with punctation widely scattered over whole surface, neck well marked, entirely covered by an elongated polygonal reticulation and with two longitudinal series of small setal pores on both sides of the neck (Fig. 1 ). Labrum tridentate with two small lateral denticles and protruding median denticle, bearing eight long setae (Fig. 2 ). Antennae with antennomeres markedly setulate (especially the last one) progressively increasing in size from the third antennomere onwards, ending with the last very thickened (Fig. 1 ).

Pronotum as long as wide and widest at anterior angles, subparallel-sided; anterior and posterior margins almost straight and anterior and posterior angles rounded; surface covered with small, scattered punctation, with very short setae (Fig. 1 ).

Elytra small and strongly narrowed at base; distinctly narrower than pronotum and subparallel (Fig. 1 ); surface covered by punctation similar to that on pronotum and by an isodiametric polygonal microsculpture.

Abdomen tergites with polygonal reticulation and widely scattered punctation; the first visible tergite is trapezoidal and the second to fifth tergites quadrangular; tergite VIII posterior margin regularly projected into a point at middle (Fig. 3 ). Sternite VIII symmetrical, posterior margin with small median excision bearing two distinct blunt protuberances on both sides (Fig. 4 ).

Legs with the metatrochanter unarmed, without denticles or spiniform process.

Aedeagus. Sternal plate long and narrow, with the external margin serrate (Figs 5a , 6a ); endophallus with two accessory pieces (i.e. copulatory pieces sensu Coiffait (1959)): one dorsal, forked at the apical end (Figs 5c , 6c ) and other central and stiletto-shaped (Figs 5b , 6b ).

Female. General appearance as the male, except for unmodified sternite VIII.

Differential diagnosis.

Entomoculia vulcanica sp. nov. is very similar, at least in one of the characters of the external morphology, to the two species known from the Canary Islands: E. canariensis from the Island of La Gomera and E. lauricola from the Island of Tenerife. This character is the metatrochanter of the male, without denticle or spiniform process; however, E. vulcanica sp. nov. is separated from both, besides the morphology of the aedeagus and sternite VIII clearly different, by having the labrum tridentate (Fig. 2 ), with only one denticle in the other two Canarian species. The new species differs completely from all non-Canarian species of the genus, as these have the labrum with two denticles and the metatrochanter of the male armed with a denticle or spiniform process. For illustrations of the aedeagus, male sternite VIII and labrum of E. canariensis and E. lauricola , see Outerelo (1980) and Outerelo and Hernández (1989).

Distribution.

So far, only two nearby collecting sites are known around the Caldera de los Marteles in the north-eastern sector of the Island, also called Neocanaria in geological terms, which has a higher diversity of subterranean species compared to the rest of the Island or Paleocanaria ( Naranjo et al. 2020).

Bionomics.

This new species has been collected in the central east region of the Island of Gran Canaria, in two nearby localities showing slight geological and floristic differences. The locality described in labels as "Caldera de Los Marteles" is, in fact, a pyroclastic cinder cone near the volcanic caldera, comprised of 1-6 cm lapilli, volcanic bombs, and slag (up to 70 cm) (Figs 9 , 10 ). In turn, Los Majaletes is located at a lower altitude and is geologically characterised by stacks of massive basalt flows up to 2-3 m thick with interspersed scoriaceous layers that must function as a deep MSS. The vegetation at Caldera de Los Marteles is dominated by a pine woodland of Pinus canariensis C. Sm., with clearings occupied by shrubby vegetation with Adenocarpus foliolosus (Aiton) DC., Chamaecytisus proliferus (L. f.) Link, Euphorbia regis-jubae J. Gay, Micromeria benthamii Webb & Berthel. and Teline microphylla (DC.) P. E. Gibbs & Dingwall (Fig. 7 ). At Los Majaletes, the pines are absent, the vegetation being dominated by the same assembly of bushes (Fig. 8 ).

The model of a subterranean trap, used to study the biodiversity of the MSS at these two localities, has led us to discover a rich underground invertebrate community of many different taxonomical groups. Most of this fauna are epigean species non-adapted to subterranean life, which penetrate through the fissures of the soil until reaching the MSS, attracted by the bait in the traps or because the environmental conditions of this habitat are suitable for part of their life cycle. However, what is really striking about the MSS of these two localities is the amount of differently adapted subterranean species that we have collected there over the years, using this model of trap. Together with this new species of Entomoculia , we have collected the pseudoscorpion Occidenchthonius beieri Zaragoza, 2017; the spiders Agraecina canariensis Wunderlich, 1992, Walckenaeria subterranea Wunderlich, 2011 and undescribed blind species of the genera Dysdera Latreille, 1804 and Macarophaeus Wunderlich, 2011; a new species of blind opilion, the millipede Dolichoiulus oromii Enghoff, 2012; the cockroach Symploce microphthalma Izquierdo & Medina, 1992; together with new blind species of the beetle genera Lymnastis Motschulsky, 1862 ( Carabidae ), Euconnus Thomson, 1859, Domene Fauvel, 1872 ( Staphylinidae ) and Oromia Alonso-Zarazaga, 1987 ( Curculionidae ).

Etymology.

The specific name refers to the presence of this new species on a volcanic island.

Discussion.

For the moment, all the Canarian species of the genus Entomoculia are characterised by lacking a denticle or spiniform process on the metatrochanter of the male and by having a different number of denticles on the labrum (one or three), compared to non-Canarian species of the genus; with the metatrochanter of the male armed with a denticle or spiniform process and with the labrum bidentate. Due to these morphological peculiarities, Outerelo and Hernández (1989) considered that the Canarian species of Entomoculia could be included in a new subgenus or even in a genus that presents a series of characters shared with the genera Entomoculia and Mesotyphlus Coiffait, 1957, although it could be that this is only a distinct group of species belonging to the genus Entomoculia that are found exclusively in the Canary Islands. Further molecular data and morphological studies of the Canarian species of Entomoculia will probably provide the necessary data to establish their correct taxonomic position.

Figures

Figures 1 - 6. Entomoculia (Stenotyphlus) vulcanica sp. nov. 1. Habitus in dorsal view; 2. Labrum in dorsal view; 3. Male tergite VII; 4. Male sternite VIII; 5. Aedeagus in right lateral view; 6. Aedeagus in left lateral view; a) Sternal plate; b) Dorsal accessory piece; c) Central accessory piece.

Figures 7 - 10. Habitat of Entomoculia (Stenotyphlus) vulcanica sp. nov. 7. Appearance of the vegetation in Caldera de Los Marteles; 8. Appearance of vegetation at Los Majaletes; 9. Terrain of cinder cone excavated in road construction near Caldera de Los Marteles, showing the presence of an MSS; 10. Detail of pyroclastic deposit that forms the MSS in the same cinder cone.