Trechus tatai Reboleira & Ortuño, 2010

Reboleira, Ana Sofia P. S., Ortuño, Vicente M., Gonçalves, Fernando & Oromí, Pedro, 2010, A hypogean new species of Trechus Clairville, 1806 (Coleoptera, Carabidae) from Portugal and considerations about the T. f u l v u s species group, Zootaxa 2689, pp. 15-26 : 16-24

Trechus tatai Reboleira & Ortuño , new species

Figs, 2–5, 7f)

Diagnosis: Microphtalmous, rudimentary wings, depigmented and slim body, general habitus more graceful than Trechus fulvus , colour light brown. Pronotum transverse and slightly cordate. Elytra convex, slightly protruding shoulders with eight well defined striae, humeral region slightly marked. Both sexes with similar external morphology, except for the first two protarsomeres, which are dilated in males. Shape of aedeagus as in figure 3; median lobe of the aedeagus similar to T. fulvus and T. lunai , but differing in the structure of copulatory pieces. Female genitalia as in the T. fulvus -group ( Fig. 4–5 ).

Description. Length of holotype: 6.2 mm. Lenght of paratypes: males 5.2–5.9 mm, females 4.8–6.

Head: Head slightly longer than wider (until the anterior margin of clypeus); mandibular, labial and maxillar pieces typical of the genus; labial tooth slightly scooped-out; in dorsal view, two deep frontal sulci bordering ocular areas on both sides, fading at the level of the posterior supraocular setae; reduced eyes that near the temple constitute a barely convex surface; antennae filiform and long (reaching ½ of the elytra lenght) and densely setulose except in the first antennomere; 3rd antennomere clearly longer than 4th; labrum scooped-out in the anterior margin.

Cephalic chaetotaxy: One setae in each mandibular groove: six labral setae; four clypeal setae; two supraocular bilateral setae, in wich the anterior one is at the same level as the eye.

Pronotum: Pronotum slightly convex, cordiform (ratio length/width: L/W = 0.8), its greatest width located near the insertion of the anterior seta; posterior margin (basal) as wide as anterior margin, slightly emarginate in the centre and oblique at the extremes; lateral margin visibly oblique in posterior half and sinuous near the posterior and acute angles, median sulcus well marked; side channel narrow that contacts with the wider and deeper basal fosset.

Pronotal chaetotaxy: One seta is located in the anterior ¼ of lateral margin, and another is slightly ahead of the posterior angle.

Wings: Rudimentary wings.

Elytra: Elytra convex, wide (relation lenght/width: L/W = 1.6), elliptic, reaching its greatest width at the middle; rounded shoulders, and slightly marked; short basal margin, oblique; striae deep and strongly punctate in most of its length (except in the ¼ apical of the elytra where they become fainter and smooth); 8th striae clearly grooved from the 6th umbilical setae; apical striole recurrent deep; united with the terminus of the 5th striae; scutellum striole well signposted, located on the 1st interstria; intrastriae smooth and slightly convex, lateral channel wide.

Elytral chaetotaxy: Scutellum pore in the origin of the 1st and 2nd striae; discal setae located above the 3rd striae, the anterior slightly behind the 1/6 basal and the posterior inserted in the half of the elytra; subapical seta inserted on the 2nd stria; one apical setae close to one margin (at the height of the 2nd striae) and another apical seta near the recurrent striole; umbilical series normal (4+2+2), the humeral group with 4 setae equidistant, and the apical group also with 4 setae but in pairs (two anterior setae and other two posterior).

Legs: Long and thin legs; conspicuously hairy (including the protibiae); male protarsi with the first two segments more dilated.

Abdomen: Typical of the T. fulvus -group; aedeagus ring ogival.

Aedeagus: Median lobe 0.96 mm long, not arched, sharpened apically; short apical lamina and, in lateral view, narrow with a rounded apex; basal bulb with big sagittal spoiler. Internal sac as typically in Trechus fulvus -group: in left lateral view, it shows a broad squamous surface that largely covers a sclerotized plate of subtriangular contour; more deeply, it shows a small ogival area covered with very sclerotized scales and one second sclerotized plate, elongated and projecting towards the apex. Parameres subsymmetrical (the right slightly shorter), laminated and frequently with six setae ( Fig. 3 ).

Female genitalia: external genitalia formed by dimerous IX gonopods (gonocoxites and gonosubcoxites) and IX laterotergites ( Fig. 4–5 ). Gonocoxites unguiform, with two thorn-shaped setae of considerable size on its dorsal surface (the largest and visible located near the external edge). Small groove near apex and above ventral surface, with two fine, sensorial setae. Gonocoxites short (as long as wide), with few (not exceeding six) thorn-shaped setae in the internal margin. Wing-shaped, slightly sclerotized IX laterotergite with a group of setae (not exceeding 15) over the basal margin, and another internal group (not exceeding 10 setae). Internal genitalia completely membranous; short and large tubular-shaped vagina-bursa ending in a sacciform spermatheca with densely folded walls. The spermatheca is located obliquely to the sagittal plane. The oviduct makes contact with the spermathecal complex at the base of the spermatheca (on the right side in ventral view); interior densely covered by microfringes.

Type series. Holotype: ɗ, Portugal, Serra do Montejunto, Algar do Javali, 6.VI.2009, S. Reboleira leg, deposited at VMO/UAH.

Paratypes: Same location, S. Reboleira leg.: 1 ɗ, 26.XII.2008 and 1 Ψ, 24.XII.2009, deposited at DZUL; 1 ɗ, 26.XII.2008, gold-paladium coated, 1 ɗ 24.XII.2009 and 1 Ψ, 24.XII.2009, deposited at SR; 1 Ψ, 5.IV.2009, deposited at VMO/UAH.

Etymology. The specific epithet tatai is dedicated to our friend Frederico Tátá Regala, who had greatly contributed to the field work and also discovered the type locality of the species.

Affinities and biogeographical remarks. According to the morphological characteristics proposed by Jeannel (1927), Trechus tatai n. sp. should be included in the Trechus fulvus -group, as the previously known hypogean species from Portugal T. machadoi Jeannel, 1942 , T. gamae Reboleira & Serrano, 2009 and T. lunai Reboleira & Serrano, 2009 (see Jeannel 1941 and Reboleira et al. 2009). The new hypogean species exhibits a slightly body stylization, being more graceful than the previously known species.

In the context of the Lusitanian hypogean Trechus , all of them geographically neighbouring species ( Fig. 1 ), the new species reinforces the idea of allopatric speciation in the Portuguese hypogean karst. This speciation pattern follows that postulated for the “ Trechus martinezi -lineage” from the north-eastern Baetic Mountains ( Ortuño & Arillo 2005). In the present case, the geographic isolation is probably due to a nonkarstic discontinuity along 40 km, between two different Jurassic karstic massifs: Estremenho and Montejunto.

The species that constitute the T. fulvus -group are distributed along North Africa, the Iberian Peninsula and, thanks to the wide distribution of T. fulvus , also along the Atlantic coast of northern Europe ( Jeannel 1927). Concerning to the Iberian peninsula, 12 species belonging to this group are currently known: T. fulvus Dejean, 1831 ; T. lallemantii Fairmaire, 1859 ; T. breuili Jeannel, 1913 ; T. martinezi Jeannel, 1927 ; T. machadoi Jeannel, 1941 ; T. gloriensis Jeanne, 1970 ; T. alicantinus Español, 1971 ; T. arribasi Jeanne, 1988 ; T. beltrani Toribio, 1990 ; T. torressalai Ortuño & Arillo, 2005 ; T. lunai Reboleira & A. Serrano, 2009 ; and T. gamae Reboleira & A. Serrano, 2009 . All these species except T. fulvus and T. lallemantii have a very limited distribution and are always linked to subterranean environments. Each of these species groups seems to represent a particular phyletic line characterized by a model of copulatory piece (see Jeannel 1927: 145). The internal systematics of the genus Trechus is based on the principle that homoplasy concerning complex internal structures is more improbable than in some external ones (greater or lesser enhancement of the grooves, contour design of the humeral region, design of the rear corners of pronotum, among others). However, in the opinion of Jeannel (1927) the “ T. fulvus -group” shows characteristic external features, being the most recognizable at first glance: 1) large size, accompanied by varying degrees of pigmentation and eye reduction; 2) elytra more or less elliptical with external grooves as deep as the inner ones; 3) recurrent apical striole connected with the end of the 5th stria.

A thorough study of all species of the T. fulvus -group reveals that it is heterogeneous, including some species because of its external morphology, while the male genitalic anatomy deviates from the model represented by T. fulvus . This is the case of T. gloriensis and T. arribasi which have the internal sac of the aedeagus formed by simple sclerotized parts (see Jeanne 1970; Toribio 2001). The other species of the T. fulvus -group exhibit a higher anatomical congruence (external and internal characters) consisting in two welldefined lineages within the group: T. martinezi -lineage and T. fulvus - lineage. The first lineage is formed by hypogean species that have survived in the mountains of the Mediterranean region: five species are known from Spain and three species from Algeria ( Ortuño & Arillo 2005; Ortuño 2008). T. lallemantii could be linked to this lineage according to the structure of the internal sac but not with regard to the conformation and orientation of the apical lamina of the median lobe of the aedeagus, that is more typical of the T. fulvus - lineage. The Lusitanian species of the T. fulvus -group are closer to T. fulvus as they show great similarity in the parts of the internal sac and also in the design and development of the apical lamina of the median lobe of the aedeagus. This lineage includes the most eurytopic species of the group, T. fulvus , and in the Iberian Peninsula: T. machadoi Jeannel, 1941 ; T. lunai Reboleira & Serrano, 2009 ; T. gamae Reboleira & Serrano, 2009 and T. tatai n. sp.

Figures

FIGURE 1. Hypogean beetles in karstic areas of Portugal. 1 — Trechus machadoi, 2 — Trechus gamae, 3 — Trechus lunai, 4 — Trechus tatai n. sp.

FIGURE 3. Trechus tatai n. sp. aedeagus. Trechus tatai n. sp.: a—Median lobe in lateral view; b—Left and right parameres in lateral view; c—Median lobe in dorsal view, scale bar: 0.3 mm; d—Ring, scale bar: scale bar: 0.3 mm

FIGURE 4. Trechus tatai Reboleira & Ortuño n. sp., external and internal female genitalia. Scale bar: 0.3 mm.

FIGURE 5. Trechus tatai Reboleira & Ortuño n. sp., female genital shield. Scale bar: 0.1 mm.