Geotrechus sarpedon Faille, Fresneda & Bourdeau, sp. n.
Creators: name: Faille, Arnaud
name: Fresneda, Javier
name: Bourdeau, Charles
Publisher: name: Zenodo
Year: 2013
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Carabidae
Geotrechus
Geotrechus sarpedon

description: Geotrechus sarpedon Faille, Fresneda & Bourdeau sp. n.
(Figs. 1–4)
Diagnosis. Geotrechus sarpedon sp. n. shows the diagnostic characters of the genus as currently understood, namely depigmentation, anophthalmy, apterism, “anophthalmous” habit (by opposition of the “aphaenopsian” habit: long legs and antenna, body slender): stocky, round head, pubescent, ocular furrows complete, striae obsolete, elytra pubescent. It is easily distinguishable from geographically related species of the genus by its long and sickle-shaped mandibles.
Type locality. France, Pyrénées-Atlantiques, Camou-Cihigue (Tardets-Sorholus), Grotte inférieure d´Oxibar, 493 m, UTM: 30T 6683 E 47747 N (Fig. 7).
Type series. Holotype (Fig. 1): 3 (collection C. Bourdeau, Rebigue), [label data: voucher number ZSM-L445] Camou - grotte inférieure d´Oxibar (=Idobeltse Ko Karbia), (France, Pyrénées-Atlantiques F-64), 29.VII.2011, leg. C. Bourdeau.
Description of the holotype. Habitus and size. Length from labrum to apex of elytra: 3.7 mm. Anophthalmous, apterous and depigmented; body hape stocky, robust, elytra and head densely pubescent, pronotum with scarce pubescence (Fig. 1).
Chaetotaxy. Surface of elytra pubescent, one periscutellar seta, two discal setae and one preapical seta on third stria, four humeral setae, four setae along lateral margin and two preapical setae. Humeral group of umbilicate punctures not aggregated (Fig. 4). Marginal setae of pronotum present, basal setae located before the first quarter of the length.
Head. Hairy, round, mandibles long and thin, sickle-shaped (Fig. 1). Antennae. Proportionally long. Length: 2.4 mm; densely pubescent from second antennomere. Antennal formula: see Table 3.
Article I II III IV V VI VII VIII IX X XI Length 0.2 0.217 0.217 0.217 0.225 0.225 0.3125 0.217 0.217 0.225 0.27 Pronotum. Length: 0.7 mm. Size small relative to elytra; cordate, long and strongly narrowed towards base, wider than head (width at base 0.42 mm, maximum width, at the upper quarter, 0.7 mm); apical margin distinctly wider than basal margin. Sides regularly arcuate, surface without any distinct puncture. Pronotal hind angle obtuse, not protruding.
Elytra. Length 2 mm, maximum width 1.1 mm, pubescent, convex, with marked and finely serrate shoulder, widest near apical third. Striae present although very poorly impressed, irregular, not punctuate.
Legs. Proportionally short, pubescent, tibiae straight. Male protarsomeres 1–2 strongly dilated; onychium as long as protarsomeres 2–4 combined. Tarsi pubescent; claws very slender, arcuate.
Male genitalia. Median lobe of aedeagus (Fig. 2) slightly curved in lateral view, with basal bulb and apex rounded, apical lamella well developed; parameres with three setae. Inner sac elongate and with scales, without any strongly sclerotized copulatory piece (Fig. 3).
Female diagnosis. No female specimen is known.
Etymology. Specific epithet referring to Sarpedon, son of Zeus and Europa, and brother of Minos and Rhadamanthus.
Affinities. Molecular analyses relate unambiguously the new species to A. (Hydraphaenops) vasconicus Jeannel, 1913 and A. (Hydraphaenops) galani Español, 1968 from the Spanish Basque country (Fig. 6). Aphaenops (Hydraphaenops) vasconicus is another species endemic of Arbailles massif, and was described from Oxibar (Jeannel 1913). Aphaenops (Hydraphaenops) galani occurs in a couple of cavities in the area of Guipuzcoa between Orio and Usurbil; it was the first Spanish endemic species of Hydraphaenops to be described, and is the westernmost species of the group (Español, 1968).
Most of the morphological features of the new species agree with the diagnostic characters of the genus Geotrechus: “anophthalmous” habitus, round head, presence of complete frontal furrows and robust appearance, with short legs and antennae. However, unlike the other species included in the genus Geotrechus, the species is characterized by long and sickled mandibles, a character shared with the species gathered in the polyphyletic subgenus Hydraphaenops.
Distribution and ecology. Geotrechus sarpedon sp. n. is only known from the type locality, the Grotte inférieure d´Oxibar located in the Arbailles massif, western part of the French slope of the Pyrenean chain (Fig. 5). This cave has high humidity, calcareous concretions and clay that opens 400 meters SE of the well known Grotte d’Oxibar (= grotte de Camou sensu Jeannel 1905), one of the oldest Pyrenean caves visited for biospeological purposes (Jeannel 1905). Although the Grotte inférieure d´Oxibar has been known for a long time as Idobeltse ko Karbia (Reymond 1952), it was not mentioned by Jeannel and collaborators in the first eight series of the classical “Enumérations des Grottes visitées” (Jeannel & Racovitza 1907 – 1929). The cave was described by Coiffait in the ninth series, and the author, who visited it with M. Bouillon, recorded four species from the cave, all occurring also in the nearby Oxibar cave: Laemostenus navaricus, Aphaenops jeanneli, Bathysciella jeanneli and Phacomorphus alexinae (Coiffait, 1959). All these species were also observed during our visits to the cave. Some Bathysciola grandis (Fairmaire, 1856) were also found in the cave or in the surroundings areas under stones.
The only specimen of Geotrechus sarpedon sp. n. known so far was found under a big stone in the sloping gallery before acceding to the main room of the cave (Fig. 7). The fact that this insect was never found before in the numerous caves occurring in the area suggests that the species had accidently reached the cave, and should probably live in the network of fissures of the karstic massif.
description: Published as part of Faille, Arnaud, Fresneda, Javier & Bourdeau, Charles, 2013, Discovery of a new blind ground beetle in western French Pyrenees, and its relevance to the phylogeny of Pyrenean hypogean Trechini, pp. 482-492 in Zootaxa 3686 (4) on pages 486-489, DOI: 10.11646/zootaxa.3686.4.6, http://zenodo.org/record/224015