Quaestus (Quaesticulus) pasensis Salgado, Labrada & Luque

M, José, Costas, Salgado, Moreda, Lucía Labrada & Luque, Carlos G., 2010, A new cave-dwelling species of Quaestus Schaufuss, 1861 from the Montes de Pas, Northern Spain (Coleoptera: Leiodidae: Leptodirini), Zootaxa 2484, pp. 25-34 : 28-32

Quaestus (Quaesticulus) pasensis Salgado, Labrada & Luque , new species

( Figs. 1 –7)

Type material. Holotype (3) and allotype (Ƥ): SPAIN: Cantabria: Luena: El Churrón Cave (The Churrón- Millajo Cave karst system, 30TVN 2988980475, 255 m), 27-VI-2007, Ocejo, leg. C.G.Luque ( CZUL). Paratypes: SPAIN: Cantabria: Luena: 253, 30 ƤƤ, same data as the holotype, (33, 3 ƤƤ MNHN; 33, 3 ƤƤ MZBS; 43, 4 ƤƤ JFCL; 43, 4 ƤƤ JMSC; the rest CZUL); 83, 8 ƤƤ, El Churrón Cave, 23-VIII- 2008, leg. C.G.Luque & L.Labrada ( CZUL); 403, 38 ƤƤ, Rellano Cave (30TVN2897080570, altitude 270 m), 23-VIII-2008, Ocejo, leg. C.G.Luque & L.Labrada (33, 3 ƤƤ, in MNCN; 33, 3 ƤƤ MCNA; 43, 4 ƤƤ, PMGC; the rest in CZUL); 23, 3 ƤƤ, Picón de Riolango Cave (30TVN2983880286, altitude 265 m), 25-X- 2008, Riolango, leg. C.G.Luque & L.Labrada ( CZUL); 23, 4 ƤƤ, La Resaca Cave (30TVN3000181278, altitude 320 m), 10-I-2009, Ocejo, leg. C.G.Luque & L.Labrada ( CZUL); Vega de Pas: 23, 4 ƤƤ, La Millajo Cave (The Churrón-Millajo Cave karst system, 30TVN3031081276, altitude 320 m), 10-I-2009, Guzparras, leg. C.G.Luque & L.Labrada ( CZUL).

Diagnosis. 10th antennomere almost as long as 11th; all antennomeres slender and much longer than wide; male protarsus somewhat wider than apex of protibia; elytra bearing sutural striae; median lobe of aedeagus pointed, internal sac of aedeagus exhibiting small scales and a short, slender stylet, without basal plate; spermathecal complex with short and fine spermathecal duct, somewhat dilated anteriorly.

Description. Holotype, male. Body length 2.44 mm; maximum width 1.30 mm. Uniformly ovoid body tapering posteriad; pronotum and elytra convex, completely covered with short, fine, sparse and recumbent yellowish pilosity ( Fig. 1).

Punctures on head extremely fine and superficial, seem almost non-existent giving tegument very shiny reddish brown appearance. Antennae long, surpassing half of body length; antennomeres long and cylindrical, 1st, 2nd, 7th, 9th and 10th are slightly dilated apically, all at least twice as long as wide; 11th antennomere the longest, slightly longer than 10th, 10th is slightly shorter than 9th; 4th almost as long as 3rd; 3rd, 5th and 6th are equally long (Table 1).

TABLE 1. Measurements of the holotype (male) of Quaestus pasensis sp. nov. Length (L) and maximum width (W) of antennomeres 1st to 11th (all measurements in mm).

1st 2nd 3rd 4th 5th 6th 7th 8th 9th 10th 11th L 0.145 0.162 0.107 0.100 0.107 0.107 0.133 0.091 0.140 0.136 0.167 W 0.051 0.047 0.036 0.036 0.036 0.036 0.047 0.036 0.047 0.047 0.056

Pronotum strongly transverse, widest at base, almost twice as wide as long, as wide as anterior part of elytra; lateral margins uniformly arcuate, posterior corners blunt and slightly prolonged posteriorly, angle slightly obtuse; tegument with very fine superficial punctation. Mesoventral carina as in group 2C ( Salgado 1996: see Figures), high, laminar and long, reaching metaventrite; anterior edge of carina weakly curved, slightly prominent, ventral edge straight and narrow; the strongly rounded vertex forms an obtuse angle.

Elytra elongated, 1.44 times as long as wide, widest near basal ¼, somewhat wider than pronotum (1.1 ratio); lateral margins uniformly curved to strongly rounded apex. Sutural striae well developed.

Legs long and slender. Foretarsus with 1st–4th tarsomeres dilated, 1st tarsomere 1.13 times as wide as apex of tibia; protarsus elongate, one and a half times longer than wide; mesotibia somewhat arcuate and metatibia slightly undulate.

Aedeagus (Figs. 2, 3) 0.49 mm long; in lateral view (Fig. 3) widely arcuate, forming obtuse angle near the middle; in dorsal view (Fig. 2) median lobe with uniformly arcuate lateral margins and weakly pointed apex. Ventral lamina of tegmen wide and rounded, well sclerotized, shorter than basal lamina. Parameres slender, almost reaching apex of median lobe, apical club weakly dilated and subrectangular, with three fairly long setae, two apically with insertion pores very close to each other and one basally, clearly distant from the other two (Fig. 4). Internal sac with short slender stylet lacking basal plate and surrounded by small scales; in apical half with narrow poorly visible reinforcing bands (Fig. 5).

Allotype, female. Body length 2.28 mm. Similar to male, except 1st–4th protarsomeres not dilated and antennae slightly shorter, with antennomeres wider than in male (Table 2).

TABLE 2. Measurements of the allotype (female) of Quaestus pasensis sp. nov. Length (L) and maximum width (W) of antennomeres 1st to 11th (all measurements in mm).

1st 2nd 3rd 4th 5th 6th 7th 8th 9th 10th 11th L 0.138 0.147 0.100 0.096 0.100 0.100 0.113 0.076 0.113 0.109 0.151 W 0.047 0.040 0.033 0.033 0.033 0.033 0.040 0.033 0.040 0.040 0.051 Spiculum ventrale of 8th urosternite short and fine, sides almost parallel and apex rounded (Fig. 6).

Spermathecal complex distinct, 0.14 mm long, bilobed, basal lobe ovoid, longer and wider than spherical apical lobe, both lobes well-sclerotized; the part joining lobes membranous, as long as apical lobe; spermathecal duct short and thin, 3-4 times as long as spermatheca, widened at beginning, posterior part directly joined to dorsal face of bursa copulatrix; spermathecal gland small, rounded and membranous usually not easily discernible, opens into widened anterior part of the spermathecal duct (Fig. 7).

FIGURES 2–7. Details of Quaestus pasensis sp. nov. 2: aedeagus in dorsal view; 3: aedeagus in lateral view; 4: apical club of the right paramere; 5: sclerotized structures of internal sac; 6: ventral spine of 8th female urosternite; 7: spermathecal complex.

Variability. Body length of the paratypes ranges from 2.25 to 2.50 mm.

Discussion. Quaestus pasensis belongs to the subgenus Quaesticulus Schaufuss, 1861 , based on the following characters: elytra bearing sutural stria, internal sac without developed sclerotized formations and with stylet lacking basal plate, spermathecal duct short with spermathecal gland small and membranous ( Salgado et al. 2008).

Within Quaestus the new species belongs to section IV (originally established by Jeannel(1924)), characterized by two characters: 11th antennomere slightly longer than 10th, and all antennomeres clearly longer than wide. Section IV includes two additional species: Q. minos ( Jeannel, 1909) and Q. filicornis ( Uhagón, 1881) . The new species differs from them in the shape of antennae, protarsi, mesoventral carina and the structure of the aedeagus; in Q. minos and Q. filicornis the antennae are longer, protarsi are wider, mesoventral carina is stronger, the parameres and stylet of the aedeagus are longer and more robust.

Externally, the new species is most similar to Q. autumnalis (Escalera, 1998) , a member of section III ( Jeannel, 1924). Quaestus pasensis can be separated from Q. autumnalis based on the following characters: 1) in Q. autumnalis all antennomeres robust (slender in Q. pasensis ) and 11th antennomere almost twice as long as 10th (subequal in Q. pasensis ); 2) in Q. autumnalis ventral edge of mesoventral carina medially expanded (narrow throughout in Q. pasensis ); 3) in Q. autumnalis protarsus always narrower than apex of protibia (clearly wider in Q. pasensis ); 4) Q. autumnalis apex of median lobe blunt (pointed in Q. pasensis ) and setae of parameres very long and undulate (much shorter and not undulate in Q. pasensis ).

Quaestus pasensis is restricted to a small karstic area of some 1 km 2, and clearly isolated geographically from its most proximate species, Q. autumnalis towards the north-west and Q. minos towards the north-east by a strip of overthrusts. Fig 8 B indicates the locations of the caves inhabited by the three species and clearly demonstrates gaps between the three species areas. The distribution area of Q. pasensis appears to be restricted to the karst-fissured aquifer systems in the Upper Jurassic carbonate rocks within the Ocejo karst system that stretches through the municipal districts of Luena and Vega de Pas.

Sampling was done in five caves: El Churrón, Relleno, Picón de Riolango, La Resaca and La Millajo ( Fig. 9 ). El Churrón is about 2.5 km long and it is the most important cave explored in the western part of the Pas Mountains. The cave is situated on a fault inscribed on a tectonical alignment controlled by a system of fractures in a general N 50–70º W and N 160–170º E direction. The other four caves are shorter, the longest of them being the Picón de Riolango Cave located at a roadside and consisting of a network of short galleries about 60 m long.

In all caves where Q. pasensis has been recorded it coexists with Q. sharpi nigricans ( Jeannel, 1924) , a subspecies widely distributed in the north eastern karstic area of Cantabria province and reported from almost one hundred caves ( Salgado, 1976, 1994). Quaestus pasensis was found only in samples from the central to the deepest parts of the caves (in greater numbers), whereas the specimens of Q. sharpi nigricans were collected in small series particulary near the cave entrances.

Quaestus pasensis was always collected in accumulations of organic matter. In El Churrón Cave, it has been found in wet remains of rotten wood; in the four other caves in old and mouldy bat manure. This species reaches the dark zone of the caves, near very wet areas; it has been found in deep zones where the air humidity is near saturation point, 95 to 99 %, and temperatures are between 10 and 14 ºC.

Etymology. The specific name is derived from the Pas Mountains (Cantabria, Spain), the karst region where the species occurs.

Figures

FIGURES 8. Location of the caves inhabited by Quaestus autumnalis (1 – 29), Q. pasensis sp. nov. (30 – 34) and Q. minos (35 – 42). (A) Geographical map of the area; (B) Distribution of the caves. Grey areas indicate rock outcrops containing limestone. Scale 1: 500.000. Squares 10 x 10 km. For cave names, coordinates and altitudes see Appendix.

FIGURE 9. Detailed map of study area indicating location of the five caves inhabited by Quaestus pasensis sp. nov. (courtesy of the “ Niphargus ” Speleological Club). UTM grid 250 x 250 m.