Aphaenops (Aphaenops) parvulus Faille, Bourdeau & Fresneda

Faille, Arnaud, Bourdeau, Charles & Fresneda, Javier, 2010, A new species of blind Trechinae from the Pyrenees of Huesca, and its position within Aphaenops (sensu stricto) (Coleoptera: Carabidae: Trechini), Zootaxa 2566, pp. 49-56 : 51-55

Aphaenops (Aphaenops) parvulus Faille, Bourdeau & Fresneda sp. n.

( Figs. 1 , 3 )

Diagnosis. Aphaenops parvulus sp. n. shows the characteristics of the genus, namely, depigmentation, ocular furrows shortened, not complete, striae almost erased, elytra glabrous with only some long setae in the border of elytra and on the disk, chitinous membrane of the endophallus staying on the right side, not symmetrically placed. It is easily distinguishable from geographically related species of the genus because of its small size.

Type locality. Spain, Huesca, Villanúa, Cueva de Esjamundo (= Cueva Nueva), 980 m, UTM (WGS 84): 30 T 701860 4728657.

Type series. Holotype ( Fig. 1 ): ɗ (Museu de Zoologia, Barcelona), [label data: voucher number MZB- AF133] Cueva de Esjamundo, Villanúa, ( Spain, Huesca), 8.VIII.2009, leg. C. Bourdeau, A. Faille & J. Fresneda. Paratypes (Muséum National d’Histoire Naturelle, Paris, and authors’ collections): 1 ɗ ( MNHN), remains of 2 ɗ (elytra, abdomen with genitalia), remains of 1 & (head, pronotum, elytra, abdomen with genitalia) and 11 exemplars (elytra, 4 exemplars with pronotum and head, sex unknown): same locality, data and collectors than the holotype. Remains of 1 ɗ (elytra, abdomen with genitalia) and 1 & (head, pronotum, elytra, abdomen with genitalia), 6.VI.2009, same locality and collectors. Remains of 7 exemplars (elytra and pronotum, 2 exemplars with head, sex unknown), 27.IX.2009, same locality and collectors.

Description of the holotype. Habitus and size. Length from labrum to apex of elytra: 5 mm. Anophthalmous and depigmented; stocky, robust, with cordate pronotum ( Fig. 1 ). microsculpture fine but distinct, consisting of isodiametric meshes.

Chetotaxy. Surface of elytra glabrous with the exception of a periscutellar seta, two setae on the disk, four humeral setae, four setae along lateral margin and two preapical setae. Marginal setae of pronotum present, the basal ones located before the first third of the length. Ventral pubescence limited to one seta on each half sternite.

Head. Glabrous; round; mandibles robust with a tooth at internal edge of the right mandible (width 1 mm). Penultimate segment of maxillary palpus distinctly pubescent.

Antennae. Proportionally short. Length: 3.4 mm; densely pubescent from the second antennomere. Antennal formula: see Table 3.

Article I II III IV V VI VII VIII IX X XI Length 0.275 0.25 0.35 0.3375 0.325 0.3125 0.3125 0.3 0.275 0.2625 0.4

Pronotum. Cordate, transverse and strongly narrowing towards base (length 0.8 mm x width 0.9 mm); sides very arcuate, maximum width in the anterior third, without any distinct puncture. Pronotal hind angles protruding, very acute.

Elytra. About one time and half longer than wide, glabrous, convex, with marked shoulders (length: 2.9 mm). Striation obsolete; isolated punctures distributed irregularly.

Legs. Proportionally short, pubescent, tibias straight. Male protarsomeres 1–2 strongly dilated, first wider than apex of protibia; onychium longer than protarsomeres 2–4 combined.

Aedeagus ( Fig. 3 ). Median lobe elongate, in lateral view curved, parameres with respectively four (left) and five (right) setae. Copulatory piece sclerotized, elongate, forming a gut.

Female diagnosis. Only the remains of two females are known with certainty. Head, pronotum and elytra with same characteristics as the holotype. Gonocoxites glabrous.

Etymology. Specific epithet referring to the small size of the new species.

Distribution and ecology. Aphaenops (Aphaenops) parvulus sp. n. is so far known from a cave only, the Cueva de Esjamundo located in the Pyrenean chain of Huesca, north of Jaca, Spain ( Fig. 5 ).

The Esjamundo cave is a large cavity with high humidity, calcareous concretions and clay. The first part of the cave is paved with sandy soil. All the specimens of Aphaenops parvulus sp. n. were found in this dry and sandy part of the cave. None of the specimens or remains were observed in the most humid area of the cave. The fact is something exceptional within the genus Aphaenops , the species of which are usually highly hygrophilic. In spite of morphological affinities, the ecology of A. parvulus sp. n. is very different from that of the species of the Geaphaenops group, which are endogean, living in the ground and found only occasionally in caves ( Jeannel 1938; Cabidoche 1965).

The reduced area where the new species was discovered is already known for its richness in hypogean endemic Coleoptera . The new species is sympatric with the Leptodirini Bathysciola obermaieri Bolívar 1918 ( Leiodidae , Cholevinae ), which is relatively abundant especially in the soil at the entrance and in the first part of the cave, as already noted by Español (1966). The region is inhabited also by several troglobitic trechine species. Geotrechus dumonti Español 1977 is known only from a nearby cavity, Las Guixas, but was not observed in the Esjamundo cave. High altitude shafts of Peña Collarada, above Villanúa, are colonized by two species of blind Trechini , Hydraphaenops penacollaradensis Dupré 1991 and Aphaenops valleti Casale & Genest 1986 .

Some specimens of Aphaenops parvulus sp. n. were parasitized by the Ascomycete Rhachomyces girardii Lepesme & Tempère 1948 , which was described on specimens collected on Aphaenops ochsi Gaudin , and known on Aphaenops valleti Casale & Genest , A. loubensi Jeannel and A. alberti Jeannel ( Santamaria & Faille 2007) . We observed this Laboulbeniale also on Aphaenops bessoni Cabidoche , but never on the members of the subgenus Geaphaenops .

Affinities. A. (Aphaenops) parvulus sp. n. is a representative of the western lineage of Aphaenops (sensu stricto) (in the sense of Faille et al., 2010). It is the smallest species of this group and it shares common characters with some species of the subgenus Geaphaenops , especially A. rebereti Gaudin 1946 and A. cissauguensis Faille & Bourdeau 2008 . In spite of an external “ Geaphaenops -like” morphology, the head of the new species is glabrous, whereas it is pubescent in the Geaphaenops group. The elongate median lobe of the aedeagus suggests affinities of the new species with A. eskualduna Coiffait ( Fig. 4 ). The latter ( Fig. 2 ) was described from La Verna cave, Pierre Saint Martin massif, Sainte Engrâce, in the French western Pyrenees and was supposed to be close to A. bucephalus Dieck 1869 from Ariège and Haute-Garonne ( Coiffait 1959). The study of troglobitic Trechini at the Museu de Zoologia of Barcelona allowed us to identify a specimen of A.

eskualduna collected in the Spanish side of the Pyrenees: 1 ɗ, Huesca, Ansó, Gamueta, Avenc G-171, 9.VII.1983, O. Escolà leg. (new record).

A. parvulus sp. n. shares the pubescent penultimate segment of maxillary palpus with A. eskualduna and all species of Geaphaenops , whereas that segment is glabrous in all other species of the Aphaenops (sensu stricto) clade. This character is also shared with A. mensioni Lagar , species of uncertain affinities from the central Spanish Pyrenees.

Figures

FIGURE 5. Map of Pyrenees showing the distribution of Aphaenops parvulus sp. n. (red circle), A. eskualduna Coiffait (green circles) and the general distribution of the Aphaenops (sensu stricto) clade (yellow line).

FIGURES 1 – 2. Habitus. 1 ― holotype of Aphaenops parvulus sp. n.; 2 ― A. eskualduna Coiffait.

FIGURES 3 – 4. Aedeagus in lateral view. 3 ― holotype of Aphaenops parvulus sp. n.; 4 ― A. eskualduna Coiffait.