Trechus arrecheai Ortuño, Gilgado & Cuesta, 2014

Ortuño, Vicente M., Cuesta, Eva, Gilgado, José D. & Ledesma, Enrique, 2014, A new hypogean Trechus Clairville (Coleoptera, Carabidae, Trechini) discovered in a non-calcareous Superficial Subterranean Habitat of the Iberian System (Central Spain), Zootaxa 3802 (3), pp. 359-372 : 361-365

Trechus arrecheai Ortuño, Gilgado & Cuesta n. sp.

Figures 2–6

Diagnosis: Anophthalmous (small ocular scars). Depigmented (testaceous) and glabrous (optical microscopy observed) integument. Pronotum markedly cordiform, much wider than long; hind angles are sharp and right. Elytra very slightly convex and sub-oval; shoulders rounded, and slightly marked; short basal margin, oblique; eight well defined striae. Without developed wings. Both sexes with similar external morphology, except for the first two protarsomeres, which are dilated in males.

Description. Length: 4.06–4.74 mm (from tip of mandible to elytron apex).

Head as wide as long (without considering mandibles); robust in comparison with pronotum. Mandibles, labial and maxillary pieces as typical of the genus. Labium emarginate with a tooth grooved, bidentate. Deep frontal sulci go round ocular area and extend towards clypeus. Ocular area and temples strongly convex and long, due to ocular regression. Non-functional eyes, reduced to small scars located in the front of ocular area. Antennae filiform, pilose and long, exceeding basal third of elytra. Cephalic chaetotaxy: one seta in the sulcus of each mandible; six setae on labrum; two setae on labial disc and eight setae on prebasilar area; four setae on clypeus; two pair of supraocular setae (bilateral disposition), the anterior pairs slightly behind the ocular scar.

Pronotum slightly convex, much wider than long (length/width = 0.75–0.85), maximum width in distal third. Basal margin rectilinear and about as long as the anterior margin. Lateral margin regularly curved in distal part and markedly sinuous in basal half; hind angles are sharp and right. Lateral sulcus deep and narrow. Pronotum disc with a central sulcus pronounced. Basal foveae wide, deep and without micropunctures. Pronotal chaetotaxy: two setae (bilateral position), one anterior seta in the distal fifth of the pronotum length and one posterior seta next to hind angle.

Elytra sub-oval, very slightly convex and reaching their greatest width behind the middle. Shoulders rounded and slightly marked. Basal margin short and very oblique. Striae well-defined and strongly punctuate in most of their length (except in the apical 1/4 of the elytra where they become fainter and smooth). 8th stria well-separated from lateral sulcus. Apical recurrent striole deep; united with the terminus of the 5th stria. Scutellar striole well signposted, short and located on the 1st interstria. Interstriae smooth and very slightly convex. Lateral sulcus wide. Elytral chaetotaxy: scutellar pore at the beginning of 1st stria; discal setae located in the 3rd stria (anterior seta slightly behind the basal 1/6 and posterior seta inserted in the half of the elytra); subapical seta inserted close to the 2nd stria; one apical seta in the continuation of the second stria near elytron margin, and another apical seta near the recurrent striole; umbilical series normal (4+2+2), the humeral group with four equidistant setae, and the apical group also with four setae but in pairs (two anterior and two posterior setae).

Legs typical of the genus; long and thin; conspicuously hairy (including the protibia apex); male protarsi with the first two segments dilated. Dorsal external surface of foretibia with a narrow longitudinal sulcus.

Abdomen. Typical of the Trechus ; aedeagus ring ogival.

Aedeagus. Median lobe thin, falciform; apex blunt, slightly fallen (lateral view) and widely rounded (dorsal view); inner sac with a single elongated copulatory piece, in the form of a concave lamina sharpened towards the apical margin, around it with a cloud of squamous structures; parameras subsymmetrical with four apical setae (in occasions 5 or 6, with those supernumerary smaller in size).

Female genitalia. External genitalia (= genital shield) formed by dimerous IX gonopods (gonocoxites and gonosubcoxites) and IX laterotergites; gonocoxites unguiform, with three thorn-shaped setae on its dorsal surface (the largest and visible located near the external edge) two with considerable size; small groove near apex and above ventral surface, with two fine, sensorial setae; gonosubcoxite short (as long as wide), globe-shaped, with three thorn-shaped setae (basal seta larger) in internal margin and another seta (finer than the other three) in basal margin; wing-shaped, slightly sclerotized (except external and anterior margins) IX laterotergite with one group of setae over basal margin (approximately eight) and one more internal group (approximately nine). Internal genitalia (= spermathecal complex) completely membranous; short and tubular-shaped vagina and sacciform bursa copulatrix; the spermatheca is a large blind prolongation in distal end of bursa copulatrix and is located obliquely to the sagittal plane; the odd oviduct makes contact with the spermathecal complex at the base of the spermatheca.

Type series. Holotype: 1 male, trap set on 11-VII-2013 and recovered on 22-X-2013. Paratypes: 1 male (teneral) and 3 females, trap set on 6-VI-2012 and recovered on 25-IX-2012; 2 females, trap set on 25-IV-2013 and recovered on 11-VII-2013. All: Moncayo Massif, Tarazona, Zaragoza, Spain, altitude: 1440 m.a.s.l. UTM: 30TXM02, V.M. Ortuño et al. leg. All type material is deposited in the Department of Life Sciences – V.M. Ortuño (DZAF-UA/VMO), University of Alcalá, Alcalá de Henares (Madrid, Spain).

Etymology. The specific epithet “ arrecheai ” is dedicated to our friend Enrique Arrechea, Manager of the Forest Management Unit, Provincial Environment Service of Zaragoza (Aragón Government), who favoured the research in the Moncayo Natural Park and also greatly contributed to the field work.

Accompanying fauna: Among the collected specimens captured by the SSDs ( Table 1 ) the following groups are predominant: Collembola, Acari, Polydesmida, Diptera, Coleoptera Staphylinidae , Coleoptera Leiodidae and Arachnida. Both Collembola and Acari may be the main source of food for T. arrecheai n. sp. In addition to other less represented species, such as some larvae of Coleoptera and Diptera. Some predators may also compete with T. arrecheai n. sp. or even prey upon it, such as some Staphylinidae (imagoes and larvae), Lithobiomorpha, Aranea, Pseudoescorpiones, or even some micro mammals of the family Soricidae that have been detected dwelling in the widest interstices of this MSS. The trap in the SSD 3 (the only one where T. arrecheai n. sp. was captured) presents the same pattern as the rest of the SSDs, although it contained a slightly higher percentage of Diptera and Acari.

Figures

FIGURE 2. Habitus (female) of Trechus arrecheai Ortuño, Gilgado & Cuesta n. sp. Scale bar: 1 mm.

FIGURE 3. Detail of the ocular region of Trechus arrecheai Ortuño, Gilgado & Cuesta n. sp. Scale bar: 0.5 mm.

FIGURE 4. Labium, labial pieces and prebasilar of Trechus arrecheai Ortuño, Gilgado & Cuesta n. sp. Scale bar: 0.2 mm.

FIGURE 5. Aedeagus and aedeagus ring of Trechus arrecheai Ortuño, Gilgado & Cuesta n. sp. A: median lobe in left lateral view. B: left paramere in left lateral view. C: right paramere in right lateral view. D: aedeagus in dorsal view. E: aedeagus ring. Scale bars, A – D: 0.2 mm; E: 0.3 mm.

FIGURE 6. Female genitalia of Trechus arrecheai Ortuño, Gilgado & Cuesta n. sp. A: genital armour and spermathecal complex. B: detail of the genital armour. Scale bar A: 0.3 mm; B: 0.1 mm.