We provide the first molecular phylogeny based on a thorough taxonomic sampling of all Pyrenean species of the tribe Trechini occurring in the subterranean environment sensu lato (soil and cave), with a complete taxonomic inventory of all valid species. Based on this analysis and a careful morphological study, a new classification is proposed. All species of the genera Aphaenops Bonvouloir, 1862 and Geotrechus Jeannel, 1919 are included in a single genus, Aphaenops, which is split into eleven subgenera: subgenus Aphaenops sensu stricto (= Geaphaenops syn. n.), with type species Aphoenops leschenaulti Bonvouloir, 1862; subgenus Argonotrechus subgen. n., with type species Anophthalmus orpheus Dieck, 1869; subgenus Aurigerotrechus subgen. n., with type species Trechus (Anophthalmus) vulcanus Abeille de Perrin, 1904; subgenus Ceretotrechus subgen. n., with type species Geotrechus ubachi Español, 1965; subgenus Dupreaphaenops subgen. n., with type species Aphaenops vasconicus Jeannel, 1913; subgenus Geotrechidius sensu novo, with type species Anophthalmus gallicus Delarouzée, 1857; subgenus Geotrechus stat. n., with type species Anophthalmus discontignyi Fairmaire, 1863; subgenus Hydraphaenops sensu novo (= Pubaphaenops, Cerbaphaenops syn. n. and Simaphaenops syn. n.), with type species Anophtalmus ehlersi Abeille de Perrin, 1872; subgenus Nafarroaphaenops subgen. n., with type species Aphaenops (Hydraphaenops) giraudi Ochs, 1938; subgenus Pyreneotrechus subgen. n., with type species Geotrechus (Geotrechidius) aldensis Jeannel, 1955; subgenus Riberaphaenops subgen. n., with type species Geotrechus holcartensis Genest, 1977. Two of the subgenera are monospecific and were erected to place two morphologically and genetically divergent species, Aphaenops (Argonotrechus) orpheus and Aphaenops (Pyreneotrechus) aldensis. The former subgenera Cerbaphaenops and Simaphaenops are included in the large monophyletic subgenus Hydraphaenops, the paraphyletic subgenus Geaphaenops is included in the subgenus Aphaenops and the synonymy of Arachnaphaenops, Cephalaphaenops and Pubaphaenops with Aphaenops is confirmed. A full list of species, including 68 new combinations at the generic or subgeneric level, is presented.
Die vorliegende Arbeit liefert die erste molekular Phylogenie der in den Pyrenäen vorkommenden Arten des Tribus Trechini. Diese basiert auf einer genauen taxonomischen Probennahme aller im weitesten Sinne in unterirdischen Umgebungen (Boden und Höhle) vorkommenden Arten und beinhaltet eine komplette taxonomische Liste aller validen Arten. Auf der Grundlage dieser Analyse und einer sorgfältigen morphologischen Untersuchung wird eine neue Klassifizierung vorgeschlagen. Alle Arten der Gattungen Aphaenops Bonvouloir, 1862 und Geotrechus Jeannel, 1919 werden in einer einzigen Gattung, Aphaenops, zusammengefasst, die in elf Untergattungen aufgeteilt wird: Untergattung Aphaenops sensu stricto (= Geaphaenops syn. n.), mit der Typusart Aphoenops leschenaulti Bonvouloir, 1862; Untergattung Argonotrechus subgen. n., mit der Typusart Anophthalmus orpheus Dieck, 1869; Untergattung Aurigerotrechus subgen. n., mit der Typusart Trechus (Anophthalmus) vulcanus Abeille de Perrin, 1904; Untergattung Ceretotrechus subgen. n., mit der Typusart Geotrechus ubachi Español, 1965; Untergattung Dupreaphaenops subgen. n., mit der Typusart Aphaenops vasconicus Jeannel, 1913; Untergattung Geotrechidius sensu novo, mit der Typusart Anophthalmus gallicus Delarouzée, 1857; Untergattung Geotrechus stat. n., mit der Typusart Anophthalmus discontignyi Fairmaire, 1863; Untergattung Hydraphaenops sensu novo (= Pubaphaenops, Cerbaphaenops syn. n. und Simaphaenops syn. n.), mit der Typusart Anophtalmus ehlersi Abeille de Perrin, 1872; Untergattung Nafarroaphaenops subgen. n., mit der Typusart Aphaenops (Hydraphaenops) giraudi Ochs, 1938; Untergattung Pyreneotrechus subgen. n., mit der Typusart Geotrechus (Geotrechidius) aldensis Jeannel, 1955; Untergattung Riberaphaenops subgen. n., mit der Typusart Geotrechus holcartensis Genest, 1977. Zwei der Untergattungen sind monospezifisch und wurden aufgestellt, um zwei morphologisch und genetisch divergente Arten, Aphaenops (Argonotrechus) orpheus und Aphaenops (Pyreneotrechus) aldensis, zu klassifizieren. Die früheren Untergattungen Cerbaphaenops und Simaphaenops werden in die große monophyletische Untergattung Hydraphaenopsaufgenommen, die paraphyletische Untergattung Geaphaenops wird in die Untergattung Aphaenops gestellt und die Synonymie von Arachnaphaenops, Cephalaphaenops und Pubaphaenops mit Aphaenops wird bestätigt. Eine vollständige Artenliste, einschließlich 68 neuer Kombinationen auf Gattungs- oder Untergattungsebene, wird hier präsentiert.
Introduction
“Au premier abord, un Geotrechus orpheus Dieck et un Aphaenops pluto Dieck sembleraient appartenir à deux lignées très distinctes. En réalité, ils sont très proches parents. Et nul meilleur exemple ne saurait être donné pour montrer qu'en systématique il faut terriblement se méfier des caractères dits d'adaptation.
” (Jeannel 1943)
Hypogean animals have fascinated evolutionary biologists since more than 200 years. Straddling the border between France and Spain, the Pyrenean chain is recognized as one of the world's hotspots of subterranean biodiversity (Culver & Sket 2000; Culver et al. 2006).
Subterranean environments host some of the less known parts of beetle diversity in the Western Palearctic and remain among the most important reservoirs of unknown biodiversity for the area, as evidenced by recent discoveries (e.g., Fresneda et al. 2009; Casale et al. 2012; GuÉorguiev 2012; Faille et al. 2015a; Njunjic et al. 2016; OrtuÑo et al. 2017; HlavÁČ et al. 2019; Lohaj & Delić 2019; Maghradze et al. 2019; Ribera & Reboleira 2019; Faille et al. 2021; Piva 2021; Casale et al. 2022; FAille & Bourdeau 2022a, 2022b). The species colonizing the hypogean environment share some remarkable morphological features known as troglomorphies: depigmentation, apter-ism, lack of eyes and elongation of appendages (Vandel 1964; Barr 1968). Beetles are the most diverse group of insects below ground, and the two main groups of beetles having diversified in the subterranean environments of the Palearctic are Leiodidae Leptodirini and Carabidae Trechini (JeannelL 1924, 1928; Casale et al. 1998).
The hypogean Trechini of the Pyrenees form one of the most diverse monophyletic groups of subterranean invertebrates in the Western Palearctic (Faille et al. 2010a). The range of the group extends from the Puigmal massif (Cerdanya) in the East to Gipuzkoa in the West, a distance of ca. 360 km in a straight line. The Pyrenean lineage is estimated to have originated during the early Miocene (Faille et al. 2013b). Three genera—Geotrechus Jeannel, 1919, Hydraphaenops Jeannel, 1926 and Aphaenops Bonvouloir, 1862—were traditionally recognized, each representing a distinct morphological type, but a molecular study of the group evidenced the non-monophyly of these three genera, highlighting the role of morphological convergence in deeply obscuring the real affinities among taxa (Faille 2006; Faille et al. 2010a). The phylogeny by Faille et al. (2010a) was a first attempt at understanding the origin of the Pyrenean Trechini radiation and testing the monophyly of the above-mentioned three genera, but relationships among species within the radiation were left largely unsolved and could not be tested due to the reduced sampling, which lacked numerous key species. Indeed, although hypogean Trechini are the most species-rich group of ground beetles, most of the species are extremely rare in the field and known from few exemplars only (Jeannel 1926, 1928, 1941, 1943, 1949).
Recently, an update of the classic “Faune de France” volume on carabid beetles by RENÉ Jeannel (1941) was published (QuÉinnec & Ollivier 2011), in which the authors proposed a rearrangement of the supraspecific classification of Pyrenean subterranean Trechini based partly on the results of Faille (2006) and Faille et al. (2010a). The authors readopted the view of Jeannel, considering Hydraphaenops (one of the three previously recognized genera) as a subgenus of Aphaenops. The genus Aphaenops was split into five subgenera: Aphaenops, Geaphaenops Cabidoche, 1966, Cerbaphaenops Coiffait, 1962, Hydraphaenops and the new subgenus Simaphaenops QuÉinnec & Ollivier 2011. No subgenera were recognized in the other genus, Geotrechus, and the former subgenus Geotrechidius Jeannel, 1947 was regarded as its synonym.
The present work aims to test the validity of these different hypotheses and provide a general framework for the classification of Pyrenean Trechini, in accordance with the evolutionary history of the group. We do not consider subspecies here unless otherwise stated, and a detailed discussion on the validity of subspecies as well as on the population structure of the most widespread species will be the focus of other publications. Contrary to the recent, highly contentious work by Donabauer (2019), in which the genus Trechus Clairville was split based mainly on previous molecular works with limited sampling and without taking morphology or distribution into account, we here rename clades within a single monophyletic lineage of Trechini based on an analysis including all the known species. The group is divided into unambiguous monophyletic units largely supported by biogeography, morphological synapomorphies or a combination of morphological characters. We strongly disapprove of practices aiming at naming clades without morphological support and based on incomplete sampling of groups the complete history of which has yet to be elucidated—even more so in groups of worldwide distribution such as the genus Trechus—particularly if the only motivation is seemingly to create new names in the hope that some of them will be recovered as valid in the future.
By adding new specimens of previously included species and 28 little-known, endemic species to the study, we investigate the relationships between species in the Pyrenean hypogean radiation and propose to divide the two former genera Aphaenops (including Hydraphaenops) and Geotrechus into eleven monophyletic subgenera. By doing so, we aim to provide a clear framework for the study of Pyrenean hypogean ground beetles and for future, detailed revisions of the proposed subgenera. As mentioned above, the possible subspecific status of different populations of some species is not discussed in this contribution and should be assessed on a case-by-case basis in the context of species-group revisions.
Material and methods
Taxon sampling and DNA extraction
With 91 species recognized so far (Serrano 2013; Tronquet 2014; Faille et al. 2015a; Moravec et al. 2017; Faille & Bourdeau 2022a, 2022b), the Pyrenean radiation is one of the most speciose groups of hypogean Trechini of the Western Palearctic. Here, we included 91 specimens of 80 species belonging to this radiation, with representatives of all the subgenera recognized in QuÉinnec & Ollivier (2011) and in the present work, together with two outgroups chosen from the genus Trechus (Appendix 1). All but two species of Geotrechus sensu auct. were included (25/27 spp.), as well as a nearly complete sampling of Aphaenops (Aphaenops sensu stricto: 12/14 spp.; Geaphaenops: 6/6 spp.; Cerbaphaenops: 19/22 spp.; Hydraphaenops: 14/15 spp.; Simaphaenops: 2/4 spp.). Although the genus was described as “Aphoenops” (Bonvouloir 1862), the spelling Aphaenops is here conserved for the genus, in accordance with the opinion of previous authors (Faille et al. 2010a: Appendix A; QuÉinnec & Ollivier 2011: 163 [status of “nomen protectum” assigned to Aphaenops]) and with the latest version of the Palearctic Catalogue of Coleoptera (Moravec et al. 2017).
Specimens were collected by hand or using pitfall traps containing propylene glycol to preserve the DNA (Rubink et al. 2003; LÓpez & OromÍ 2010). We followed the extraction protocol described in Faille et al. (2010b); extractions were non-destructive, using the DNeasy Tissue Kit (Qiagen GmbH, Hilden, Germany). Extracted exemplars were then mounted on cards, with the genitalia stored in water-soluble resin (DMHF) on a transparent card pinned beneath the specimen. The tree was rooted by two species of Trechus known to belong to different groups of Trechini (Jeannel 1927; Faille et al. 2010a).
We amplified fragments of four mitochondrial genes: the 3′ end of cytochrome c oxidase subunit I (cox1); a single fragment (16S) including the 3′ end of the large ribosomal unit (rrnL), the whole tRNA-Leu gene (trnL) and the 5′ end of NADH dehydrogenase 1 (nad1), and two nuclear genes: the internal fragment of the large ribosomal unit 28S rRNA (LSU) and the 5′ end of the small ribosomal unit 18S rRNA (SSU) (see Table 1 for details of primers used). Sequences were assembled and edited using Sequencher TM 4.8 (Gene Codes, Inc., Ann Arbor, MI) and Geneious Prime 2019.2.3. Some sequences were taken from previous studies (Faille et al. 2010a, 2011, 2013a, 2013b, 2015a) (details and accession numbers in Table 2). For eight species, we failed to get all genes from a single exemplar; therefore, we combined two specimens in a single chimera (see asterisks in Table 2 Fig. 1). New sequences have been deposited in the Gen-Bank database (for accession numbers, see Table 2).
Table 1.
Primers used for gene amplification.
Morphological data
Earlier classifications (especially Jeannel 1928) grouped species based on shared general characteristics. We followed this approach by adding more characters; we first took images of 30 characters for each species, later restricting the number to 15 structures identified as phylogenetically more stable, such as the topology of setae, body pubescence, the general shape of the aedeagus, or the labial tooth and ligula. The terminology of the different kinds of elytral setae follows Juberthie et al. (1975): mc: macrochaetae (discal series); t: trichobothria (umbilicate series); tm: the four trichobothria forming the “groupe huméral” sensu Jeannel (1928).
The retained characters allowed to morphologically describe the groups in accordance with the obtained clades. Characters used to define each subgenus are listed below in their respective diagnoses or in the first sentence of each paragraph concerning the different species groups identified.
Images were taken with Olympus CH and Olympus SZX16 microscopes coupled with an Olympus C5060WZ camera (Olympus, Tokyo, Japan). Composite images were combined using the CombineZP software (Informer Technologies Inc., Dominica) and processed with Adobe Photoshop 7.0 (Adobe, San José, California).
For 10 species, no molecular data were available. We therefore considered their affinities based on morphological similarity, by looking at both external characters and characters of the male genitalia (when known). We studied all described species (and their type series in most cases) of the former genera Aphaenops (including Hydraphaenops) and Geotrechus. Vouchers and DNA samples are kept in the collections of the Muséum National d'Histoire Naturelle (Paris, France) (MNHN), Zoologische Staatssammlung München (Munich, Germany) (ZSM), Staatliches Museum für Naturkunde Stuttgart (Stuttgart, Germany) (SMNS) and of the authors.
Phylogenetic analyses
The sequences obtained were aligned using MAFFT online v.7 (Katoh et al. 2019), with the Q-INS-i algorithm (Katoh & Toh 2008) and default parameters. The sequence matrix was analysed with a fast maximum likelihood search as implemented in IQ TREE v1.6 (Nguyen et al. 2015), with the best evolutionary model (TVM+F+R3) as selected by Modelfinder (Kalyaanamoorthy et al. 2017) using the AIC (Akaike Information Criterion). We assessed topological stability with 1,000 ultrafast bootstraps (UFBoot) and additionally tested branch support using SH-like aLRT with 1,000 replicates (Nguyen et al. 2015). Maximum likelihood analyses were also conducted on the combined data matrix using RAxML 8.1.2 (Stamatakis 2006, 2014). The data set was partitioned by gene, with an independent GTR+I+G evolutionary model applied to each partition and default values for other parameters of the search. The node support values were obtained with 1,000 bootstrap replicates.
The names of the valid taxa in their new combinations, their authors, publication dates and lists of synonyms and combinations are given in Appendix 1.
Results
The topologies obtained with RAxML and IQ-TREE were largely congruent, except for minor differences in node support. As we found no incongruence and the topologies were similar, we chose to keep the topology obtained with IQ-TREE (Fig. 1a). The monophyly of this hypogean radiation of Trechini beetles was strongly supported and none of the three traditionally recognized genera was recovered as monophyletic. The polyphyly of the genera Aphaenops and Geotrechus and of the subgenera Hydraphaenops, Cerbaphaenops and Geaphaenops, under their circumscription prior to this work, is evidenced. Some well-defined species groups were recovered. A single species, Aphaenops aldensis (Jeannel, 1955), the easternmost species of the group, is sister to the whole Pyrenean radiation, suggesting an eastern origin of the lineage. Apart from this species, the genus Geotrechus is split into five well-supported clades.
The reconstructed topology of the Pyrenean subterranean Trechini lineage is consistent with previous results obtained with a smaller sampling coverage (Faille et al. 2010a).
Among the characters chosen for the morphological study, the topology of the elytral setae and the distribution of pubescence appeared to be very often informative phylogenetically. The main characters of each of the subgenera newly erected or newly defined herein are listed in Appendix 2.
The molecular phylogenetic results and the nearly complete taxon sampling allow to propose, for the first time, a new classification of the radiation, with the aim to avoid para- or polyphyletic genera and subgenera.
The following section provides brief descriptions of the new subgenera, each of them delimited according to the well-supported clades in the phylogeny. Their main diagnostic morphological characters are given, as well as new names and combinations (see Appendix 1 for a complete list of species in the newly defined genus Aphaenops).
The hypogean Pyrenean Trechini comprise 91 species, all of which are here included in a single genus: Aphaenops sensu novo; the species previously included in the genus Geotrechus are split across eight of the 11 clades of Aphaenops (Fig. 1a, b). The name Geotrechus is now restricted to the clade of Aphaenops containing Aphaenops (Geotrechus) discontignyi (Fairmaire, 1863), comb. n., the type species of Geotrechus. The subgenus Hydraphaenops sensu novo is extended to all the species previously included in the genera Cerbaphaenops and Simaphaenops. Some of the species previously recognized as belonging to the genus Hydraphaenops are included in new subgenera. The genus Geaphaenops is regarded as a junior synonym of Aphaenops s. str., syn. n.
These taxonomic changes have generated secondary homonymies, and two species are therefore renamed (see Appendix 1).
A new classification of the Pyrenean hypogean lineage of Aphaenops Genus Aphaenops Bonvouloir, 1862
Aphoenops Bonvouloir, 1862 (Bonvouloir 1862: 567), nomen oblitum.
Type species
Aphoenops leschenaulti Bonvouloir, 1862 (Bonvouloir 1862: 568) (Fig. 2).
Diagnosis
The hypogean species of Trechini traditionally gathered in the genera Aphaenops (including Hydraphaenops) and Geotrechus are all blind, depigmented and apterous. Additionally, they share the following combination of characters:
- labial tooth simple (although slightly bifid when observed at high magnification in some species);
- submentum with six setae;
- protibiae pubescent, without sulcus;
- elytra: marginal umbilicate setae with humeral group not aggregated, the third and the fourth seta distant from the margin of the elytra;
- apex of elytra: first stria running into direction of 5th longitudinal stria;
- endophallus of male genitalia with a simple copulatory piece, asymmetrical and in a lateral position (“anisotopic”, Jeannel 1928; Faille et al. 2013b).
The genus includes 91 species previously included in the former genera Aphaenops (subgenera Aphaenops, Geaphaenops, Cerbaphaenops, Hydraphaenops and Simaphaenops sensu auct.) and Geotrechus.
All representatives are endemic to the Pyrenean area and are found underground, from the soil and MSS (“Milieu Souterrain Superficiel”; Juberthie et al. 1980) to the deepest caves. Some species are preferentially found in the upper part of the karst, under stones, with some species of Hydraphaenops being more common in the deepest areas of the karst.
Here, we list the subgenera in alphabetical order together with diagnostic character states. An exhaustive list of the species can be found in Appendix 1.
1. Subgenus Aphaenops sensu stricto
= Geaphaenops Cabidoche, 1966, syn. n.
This speciose subgenus currently contains 20 species and corresponds to the “groupe leschenaulti” sensu Jeannel (1943) plus Aphaenops (Aphaenops) alberti and the species described since then [subgenera Aphaenops and Geaphaenops sensu QuÉinnec & Ollivier (2011)].
Diagnosis
Large bodied species, troglobitic or endogean (former Geaphaenops) (Fig. 2). Size variable from 5 mm [Aphaenops (Aphaenops) parvulus] to 8 mm [Aphaenops (Aphaenops) loubensi]. All species of this clade are glabrous and lacking dense pubescence on the head, with the only exception of the aberrant species Aphaenops (Aphaenops) alberti from the Arbailles Massif in France (Fig. 8b). Elytra without striae.
Distribution
This large and homogeneous clade corresponds to the “Western clade” of Faille et al. (2010a). It is distributed in the western part of the Pyrenean chain, from the Pre-Pyrenees in the Noguera Ribagorçana Valley—Aphaenops (Aphaenops) catalonicus—in the East to the Roncevaux area (Navarra)—Aphaenops (Aphaenops) ochsi—in the West.
Remarks
The clade is geographically and genetically strongly supported. Nevertheless, in spite of the large size and similar overall appearance of species in this subgenus, no unambiguous synapomorphy has been evidenced (Faille 2006). However, Aphaenops sensu stricto can be split into six species groups, each of which can be characterized morphologically and genetically.
1.1. Aphaenops (Aphaenops) eskualduna group
The species of this group are characterized by a round head, labrum slightly or deeply concave, ligula triangular and bearing six (3+3) lateral setae, the presence of a crown of setae on the maxillary palps, and male genitalia elongated, with sagittal aileron present.
The group consists of five species endemic to the Western Pyrenees. It is heterogeneous in size, some species being large [e.g., Aphaenops (Aphaenops) mensioni], others very small [e.g., Aphaenops (Aphaenops) parvulus] (Faille et al. 2010b). Some of the species are known from caves only [Aphaenops (Aphaenops) mensioni, Aphaenops (Aphaenops) parvulus, Aphaenops (Aphaenops) eskualduna], whereas others are more common in the soil and MSS [Aphaenops (Aphaenops) rebereti, Aphaenops (Aphaenops) cissauguensis].
1.2. Aphaenops (Aphaenops) jeanneli group
The species of this group share a salient though moderately acute labial tooth and median lobe of aedeagus with a dilated basal bulb and pointed apex.
Group composed of three troglobitic species from the Western Pyrenees. Aphaenops (Aphaenops) jeanneli and Aphaenops (Aphaenops) orionis are morphologically close, differing by a combination of morphological characters (shape of head, elytra and median lobe). The third species, Aphaenops (Aphaenops) alberti, endemic to the Arbailles Massif, is morphologically divergent, slender, larger in size and with a large, pubescent head (Fig. 8b) that led its descriptor to consider it close to Aphaenops (Hydraphaenops) bucephalus from Ariège, which convergently shares a similar facies, especially the large, pubescent head (Fig. 8d) (Jeannel 1939). This group is localised in the Arbailles Massif (France) and the neighbouring Urkulu, Orbara and Orion massifs (Spain).
1.3. Aphaenops (Aphaenops) leschenaulti group
Head large, temples glabrous, two discal setae. Labrum concave, labial tooth smooth, flattened. Labial ligula prow-shaped, with protruding central bulb. Male genitalia homogeneous in the three species: aedeagal median lobe small, short, with a blunt apex and without an apical lamella, widely open at base (Fig. 5). The aedeagal internal sac is covered with a broad field of uniformly-sized microtrichia.
Three species of the Central Pyrenees: two troglobitic [Aphaenops (Aphaenops) leschenaulti and Aphaenops (Aphaenops) catalonicus], one endogean [Aphaenops (Aphaenops) linderi, previously included in the subgenus Geaphaenops]. Aphaenops (Aphaenops) leschenaulti and Aphaenops (Aphaenops) linderi are endemic to the northern slope of the Pyrenees. The first is restricted to the area of Bagnères de Bigorre, whereas the second is found in the Saint Pé area. The third species, Aphaenops (Aphaenops) catalonicus, is widespread in Betesa and Bonansa, Huesca, Spain, although always rare in caves (Fresneda 1987; Faille et al. 2006).
1.4. Aphaenops (Aphaenops) loubensi group
Head triangular, labrum concave. Pronotum small, squared; body glabrous, discal series with numerous setae (usually 5–8).
Three large-bodied species from the Western Pyrenees, found in high altitude caves between the Aspe and Iraty valleys in the West (DuprÉ 1988). A fourth species, Aphaenops (Aphaenops) valleti, not available for the molecular part of this work, is tentatively included in this group. Although much smaller, this last species shares many character states with the Aphaenops (Aphaenops) loubensi group: high number (10–12) of discal setae and shape and arrangement of setae of labrum and copulatory piece among others. The male genitalia of Aphaenops (Aphaenops) valleti are of a similar structure to those of the Aphaenops (Aphaenops) loubensi group, although not hooked at the apex (Casale & Genest 1986). This species is endemic to the Somota Massif in Huesca province, Spain.
1.5. Aphaenops (Aphaenops) ochsi group
This group is characterized by some unique morphological character states, the most relevant of being the triangular shape and the conformation of the labrum with four median setae gathered in the middle (Fig. 8a). Other features (copulatory piece gutter-shaped; protruding ligula, calyx-shaped with eight setae and a prominent, two-lobed central tubercle) are characteristic of Aphaenops (Aphaenops) ochsi, but these characters have not been documented for Aphaenops (Aphaenops) fresnedai, which is known from a single, poorly preserved female exemplar.
The group consists of two troglobitic species from the Central and Western Pyrenees. Aphaenops (Aphaenops) ochsi is a widespread species occurring from the Villanúa Valley in the East to the Arce Valley in the West (Faille & Bourdeau 2011). It is found in a great variety of cavities, from warm, low-altitude caves (e.g., the Espoz and Espinal areas on the southern slope of the Pyrenees) to cold, high-altitude caves (e.g., the Pierre Saint Martin Massif at the border between France and Spain). A population of this species was recently discovered far south, in the Sierra de Leyre (DuprÉ 2017). Many subspecies have been described, some of which were recently synonymized without further explanation (Tronquet 2014). The status of the numerous populations of Aphaenops (Aphaenops) ochsi is in need of revision. The second species, Aphaenops (Aphaenops) fresnedai, is known from the female type only, found in a high-altitude abyss in Sierra de Alano (Faille & Bourdeau 2011).
1.6. Aphaenops (Aphaenops) rhadamanthus group
Homogeneous morphology, with large head scarcely pubescent, short appendages and parameres with numerous (usually 5–7) setae. Mandibular tooth squared, simple.
This group is composed of three endogean species (former Geaphaenops, in part). The species of this group are extremely rare in caves and are found in the ground and occasionally in the MSS, often mixed with species of the subgenus Geotrechidius: Aphaenops (Geotrechidius) gallicus spp., Aphaenops (Geotrechidius) jeannelianus nom. n.
2. Subgenus Argonotrechus subgen. n.
Type species
Anophthalmus orpheus Dieck, 1869: 3 (Dieck 1869: 3 [= Dieck 1870: 341]), by present designation (Figs. 3a, 6a).
Diagnosis
This morphologically distinct monospecific subgenus is very well characterized by the convex elytra with deep punctate striae, pronotum with fore angles salient and hind angles acute and divergent, presence of a transverse bulge at the base of the elytra, and bilobate labrum.
Etymology
The new name refers to the Argonauts, heroes in Greek mythology, of which Orpheus (the name of the type species) was a member.
Distribution
The only species of this subgenus is quite widespread in Ariège and Haute-Garonne (France).
Remarks
Aphaenops (Argonotrechus) orpheus is a common and widespread species, often endogean, which is morphologically distinct and genetically isolated from the other species of endogean Aphaenops. Ten subspecies have been described, of uncertain status.
Fig. 3.
Type species of the 11 subgenera of Aphaenops. a. Aphaenops (Argonotrechus) orpheus (Dieck, 1869). b. Aphaenops (Aurigerotrechus) vulcanus (Abeille de Perrin, 1904). c. Aphaenops (Ceretotrechus) ubachi (Español, 1965). d. Aphaenops (Dupreaphaenops) vasconicus Jeannel, 1913. e. Aphaenops (Geotrechidius) gallicus (Delarouzée, 1857). f. Aphaenops (Geotrechus) discontignyi (Fairmaire, 1863). g. Aphaenops (Hydraphaenops) ehlersi (Abeille de Perrin, 1872). h. Aphaenops (Nafarroaphaenops) giraudi Ochs, 1938. i. Aphaenops (Pyreneotrechus) aldensis (Jeannel, 1955). Scale bars: 2 mm.
Fig. 4.
A tiny and poorly known species, Aphaenops holcartensis (Genest, 1977), type species of the subgenus Riberaphaenops subgen. n. Scale bar: 2 mm.
3. Subgenus Aurigerotrechus subgen. n.
Type species
Trechus (Anophthalmus) vulcanus Abeille de Perrin, 1904 (Abeille De Perrin 1904: 198), by present designation (Figs. 3b, 6b).
Diagnosis
All the species of this clade share median lobe of aedeagus rounded, with sharpened apex, and sagittal aileron of male genitalia faintly developed or absent (Fig. 6b).
Etymology
From aurigera, auriferous, suggested etymology of Ariège, river and department (France) where the species of this subgenus are endemic.
Distribution
The seven species belonging to the subgenus Aurigerotrechus subgen. n. occur in Ariège, in the French Eastern Pyrenees.
Remarks
The clade is subdivided into two well-supported (99/99) groups of species: the Aphaenops (Aurigerotrechus) vulcanus group (Aphaenops vulcanus, A. sulcatus) and the Aphaenops (Aurigerotrechus) saulcyi group (Aphaenops saulcyi, A. andreae, A. palei, A. vanderberghi, A. vandelianus nom. n.).
3.1. Aphaenops (Aurigerotrechus) saulcyi group
Morphology homogeneous, characterized by a moderate size, body glabrous and short appendages. Species of this group differ from those of the A. sulcatus group by having pronotum much narrower at base, with fore angles usually protruding (a character not so marked in A. vandelianus), and completely lacking striae.
Five species are recognized in this group so far (former Geotrechus in part). The species of this group are mostly found in caves (A. saulcyi, A. andreae, A. palei) or in the ground at the entrance of caves (A. vandelianus, A. vanderberghi). The status of these last two species is in need of revision, as many intermediate populations have been discovered since their description.
3.2. Aphaenops (Aurigerotrechus) vulcanus group
Both species are characterized by elytra with visible remains of striae, pronotum much less constricted and fore angle of pronotum never protruding.
Two close species belong to this group. Aphaenops vulcanus is a species widely distributed in the Plantaurel, on both sides of the Ariège River, whereas A. sulcatus is known so far only from its type locality Aven de la Tussave (Soueix-Rogalle) (Coiffait 1959).
4. Subgenus Ceretotrechus subgen. n.
Type species
Geotrechus ubachi Español, 1965 (EspaÑol 1965: 136), by present designation (Figs. 3c, 6c).
Diagnosis
All species in this clade share elongated elytra, pronotum always longer than wide, striae hardly visible or lacking, humeral angle faintly pronounced. The sagittal aileron of the median lobe of the male genitalia is well developed (Fig. 6c).
Etymology
Ceretotrechus subgen. n. refers to the Ceretania area of the “ceretani” iberic people, cited by classical Greek and Roman historians—Polibios, Пoλύβιoς “History”, III, 8; Estrabon, Ʃτράβων “Geographia”, III, 4,11; Plinius “Natural History”, III, 22–23. From this name is derived the actual name of Cerdanya (France and Spain) or Ceret (France) in the Eastern Pyrenees, the probable centre of dispersal of this new subgenus.
Distribution
The seven species belonging to the Ceretotrechus subgen. n. clade occur in the eastern part of the Spanish Pyrenees. The group is distributed in the South-Eastern Pyrenean Mountains between Serra de Boumort and the Puigmal Massif. It reaches Serra dels Obacs in the South and Serra de Catllaràs—on the left bank of the Llobregat River—and the right bank of the Segre River in the North.
Remarks
This clade was recently revised by Faille et al. (2015a) and contains two, well-characterized groups of species.
Aphaenops (Ceretotrechus) delioti group
The two species of this group share pronotum with hind angles acute before the base, median lobe of aedeagus short, with acute apex and penultimate article of maxillary palpi with a few setae.
The two species occur on the right side of the Segre River, a narrow area between Prullans and Isòvol (G. delioti) and a small massif on the northern slope of Serra del Cadí (G. incantatus). The ancestor of the group might have become separated on the right (north) bank of the Segre River, later colonizing the distribution area of the other group on the southern bank (Faille et al. 2015a).
Aphaenops (Ceretotrechus) ubachi group
The five species of this group are characterized by the shape of the median lobe of the aedeagus, with apex rounded, pronotum with hind angles simple and maxillary palpi with penultimate segment glabrous.
The species of this group are distributed on the left (south) bank of the Segre River between the Puigmal Massif and the westernmost part of Serra del Boumort.
Fig. 6.
Morphological diversity of the male genitalia among the different subgenera of Aphaenops. a. Aphaenops (Argonotrechus) orpheus (Dieck, 1869). b. Aphaenops (Aurigerotrechus) vulcanus (Abeille de Perrin, 1904). c. Aphaenops (Ceretotrechus) ubachi (Español, 1965). d. Aphaenops (Dupreaphaenops) vasconicus Jeannel, 1913. e. Aphaenops (Geotrechidius) gallicus (Delarouzée, 1857). f. Aphaenops (Geotrechus) discontignyi (Fairmaire, 1863). g. Aphaenops (Hydraphaenops) ehlersi (Abeille de Perrin, 1872). h. Aphaenops (Nafarroaphaenops) giraudi Ochs, 1938. i. Aphaenops (Pyreneotrechus) aldensis (Jeannel, 1955). Scale bars: 2 mm.
5. Subgenus Dupreaphaenops subgen. n.
Type species
Aphaenops vasconicus Jeannel, 1913 (Jeannel 1913: 382), by present designation (Figs. 3d, 6d).
Diagnosis
The three species in this group share a pubescent body, long and sickled mandibles and median lobe of male genitalia regularly curved, with a round, blunt apex (Fig. 6d). Labial tooth triangular, flat [Aphaenops (Dupreaphaenops) galani] to slightly protruding [Aphaenops (Dupreaphaenops) sarpedon, Aphaenops (Dupreaphaenops) vasconicus]. This clade was already identified by Faille et al. (2013b).
Etymology
Named in tribute to Eric Dupré, who passed away at the beginning of the year, in recognition of his contribution to the knowledge of the cave beetle diversity of the Pyrenees, and more especially the French Basque country.
Distribution
The new subgenus groups three species endemic to the Basque country, two in France [Arbailles massif: Aphaenops (Dupreaphaenops) vasconicus, Aphaenops (Dupreaphaenops) sarpedon] and one in Spain, Aphaenops (Dupreaphaenops) galani, the westernmost species of the clade (and of the genus Aphaenops), restricted to Guipuzkoa, Spain: Macizo de Andatza and Macizo de Hernio.
6. Subgenus Geotrechidius sensu novo
Geotrechidius Jeannel, 1947 (Jeannel 1947: 102).
Type species
Anophthalmus gallicus Delarouzée, 1857 (DelarouzÉe 1857: xciv; Jeannel 1947: 102) (Figs. 3e, 6e).
Diagnosis
The seven species of Geotrechidius sensu novo are characterized by elytra glabrous or finely hairy [Aphaenops (Geotrechidius) dumonti, Aphaenops (Geotrechidius) pandellei complex] and without a crenulate humerus. The external morphology is quite homogeneous between Aphaenops (Geotrechidius) gallicus, Aphaenops (Geotrechidius) jeanneli and Aphaenops (Geotrechidius) soussieuxi; Aphaenops (Geotrechidius) dumonti is also similar to Aphaenops (Geotrechidius) gallicus. The external morphology of the species of the Aphaenops (Geotrechidius) pandellei complex is very different, especially because of the hydraphaenopsian features likely reflecting a peculiar ecology and feeding behaviour. Surprisingly, the shape of the median lobe of the aedeagus is most similar between Aphaenops (Geotrechidius) soussieuxi, Aphaenops (Geotrechidius) jeanneli and the Aphaenops (Geotrechidius) pandellei complex: the median lobe of those species is regularly curved, with a wide and rounded apex. In the two last species, Aphaenops (Geotrechidius) gallicus and Aphaenops (Geotrechidius) dumonti, the median lobe is different: long, thin and acute at the apex (Fig. 6e).
Distribution
The name Geotrechidius sensu novo is restricted to seven species occurring in the western part of the Pyrenean range. Six species are French endemics, whereas only one (A. dumonti) is a Spanish endemic.
Remarks
The genus Geotrechus was split into two by Jeannel (1947). In the subgenus Geotrechidius, he included all species with glabrous elytra without a crenulate humerus. Such characters are found in two species groups: an eastern group (“groupe vulcanus” sensu Jeannel, here assigned to Aurigerotrechus subgen. n.) and a western group (“groupe gallicus”). At that time, the species of the subgenera Pyreneotrechus subgen. n. and Ceretotrechus subgen. n., which share the same morphological features, were not known. The two subgenera, Geotrechus and Geotrechidius, were later synonymized (QuÉinnec & Ollivier 2011). Here, we restore the name Geotrechidius but restrict it to the western group—“groupe gallicus” of Jeannel (1947)—to which we add five species: one Spanish species [Aphaenops (Geotrechidius) dumonti], one species located far from the Pyrenees, in the Landes department [Aphaenops (Geotrechidius) soussieuxi] and three close species occurring in the same area but morphologically divergent, with “hydraphaenopsian” features: Aphaenops (Geotrechidius) pandellei, Aphaenops (Geotrechidius) gracilis and Aphaenops (Geotrechidius) blancheti. These three species are here treated as the Aphaenops (Geotrechidius) pandellei complex, as the differences between them are tenuous and their status as distinct species remains to be tested. The status of the various populations and closely-related species of Aphaenops (Geotrechidius) gallicus and the Aphaenops (Geotrechidius) pandellei complex, respectively, with many subspecies described and recently synonymized, is in need of revision, as suggested by the position of Aphaenops (Geotrechidius) blancheti in the tree (Fig. 1a).
7. Subgenus Geotrechus stat. n.
Geotrechus Jeannel, 1919 (Jeannel 1919: 254).
Type species
Anophthalmus discontignyi Fairmaire, 1863 (Fairmaire 1863: 3; Jeannel 1919: 254) (Figs. 3f, 6f).
Diagnosis
Species in this subgenus share head and elytra pubescent, humerus more [Aphaenops (Geotrechus) discontignyi, Aphaenops (Geotrechus) serrulatus] or less [Aphaenops (Geotrechus) orcinus, Aphaenops (Geotrechus) trophonius] serrulate (Fig. 3f), and a characteristic median lobe of the aedeagus: long and rounded in its apical part (Fig. 6f). The four species in this clade are morphologically very close.
Distribution
Geotrechus stat. n. is restricted to four species occurring between Gave de Pau in the West and the Salat River in the East.
Remarks
Aphaenops (Geotrechus) serrulatus was regarded as valid by QuÉinnec & Ollivier (2011), but as a synonym of Aphaenops (Geotrechus) orcinus orcinus by Quéinnec in Tronquet (2014). Finally, this taxon is in the list of valid species of the genus Geotrechus in Moravec et al. (2017). Aphaenops (Geotrechus) serrulatus bona species is a valid species, genetically and morphologically distinct from Aphaenops (Geotrechus) orcinus, which occurs in the same area. As already mentioned by Jeannel (1949), A. serrulatus is closely related to Aphaenops (Geotrechus) discontignyi and shares a similar shape of the male genitalia as well as a serrulate humerous.
8. Subgenus Hydraphaenops sensu novo
Hydraphaenops Jeannel, 1926 (Jeannel 1926: 234).
= Cerbaphaenops Coiffait, 1862, syn. n.
= Simaphaenops Quéinnec & Ollivier, 2011, syn. n.
Type species
Anophtalmus ehlersi Abeille de Perrin, 1872 (Abeille De Perrin 1872: 15; Jeannel 1926: 234) (Figs. 3g, 6g).
Diagnosis
This subgenus is formed of species of small size, with a pubescent head.
Distribution
With 35 species described so far, Hydraphaenops sensu novo is the most speciose group of the Pyrenean lineage, the most diverse in Ariège and Haute-Garonne, but occurring from the Ariège Valley in the East to Gave d'Aspe and the Canfranc Valley in the West.
Remarks
Hydraphaenops sensu novo includes all the species previously included in the subgenera Cerbaphaenops and Simaphaenops, as well as two groups of species of the subgenus Hydraphaenops as previously defined, including the type species Aphaenops (Hydraphaenops) ehlersi (Figs. 3g, 6g, 8c). Four species groups are unambiguously identified.
Hydraphaenops sensu novo can be split into four species groups, each of which can be characterized morphologically and genetically.
Fig. 7.
Aphaenops (Riberaphaenops) holcartensis (Genest, 1977), male genitalia (ssp. charlesi Dupré & Bourdeau).
8.1. Aphaenops (Hydraphaenops) chaudoiri group
The A. chaudoiri group is composed of three species endemic to the Central Pyrenees. The two French species are characterized by sickled mandibles, body densely pubescent except for pronotum, which is glabrous, and aedeagus curved and sharp at apex. Aphaenops (Hydraphaenops) alfambrai, a species known from the female holotype only, found in a high altitude deep shaft in the Revilla area (central Spanish Pyrenees), and which share the same chaetotactic pattern (Lagar 1979), is tentatively included in this group.
8.2. Aphaenops (Hydraphaenops) crypticola group
This clade is the most speciose group of Aphaenops (24 species so far) and includes most of the species of the former subgenus Cerbaphaenops. The morphology of the species of this clade is quite homogeneous, composed of slender pale testaceous species with long appendages and head normal, pubescent, harbouring two to six or seven discal setae, with temples moderately swollen behind and mandibles short, shorter than head [“groupe cerberus” sensu Jeannel (1941)]. A few species of the group deviate from this homogeneous morphology and were considered as belonging to other groups: Aphaenops (Hydraphaenops) bucephalus (Cephalaphaenops Jeannel), Aphaenops (Hydraphaenops) longicollis (Hydraphaenops sensu auct.), Aphaenops (Hydraphaenops) chappuisi—here found sister to the other species of the A. crypticola group—and Aphaenops (Hydraphaenops) tiresias (both Arachnaphaenops Jeanne), and Aphaenops (Hydraphaenops) laurenti (the only species of the former subgenus Pubaphaenops Genest). The A. crypticola group represents the typical “troglobie des parois stalagmitées” (Jeannel 1941), with some species locally abundant on the wet walls of caves of the northern slope of the Pyrenees; nevertheless, some species are common in the MSS (see Juberthie et al. 1980) [e.g., Aphaenops (Hydraphaenops) vandeli in Ariège]. The group is restricted to the French slope of the Pyrenean chain, where it is distributed from west of the Ariège Valley [Aphaenops (Hydraphaenops) bonneti] to Gave de Pau [Aphaenops (Hydraphaenops) aeacus]. The bulk of the diversity of this group is in Ariège. The clade is subdivided into five subclades: 8.2.1., a clade with Aphaenops (Hydraphaenops) crypticola, Aphaenops (Hydraphaenops) pluto and related species; 8.2.2., a clade with all the species of the Aphaenops (Hydraphaenops) carrerei group, including the hairy species Aphaenops (Hydraphaenops) laurenti (for which a new subgenus had previously been erected, Pubaphaenops); 8.2.3., a clade with the Aphaenops (Hydraphaenops) cerberus group + Aphaenops (Hydraphaenops) tiresias; 8.2.4., a clade with the western species, Aphaenops (Hydraphaenops) aeacus and related species; 8.2.5., a clade with low support gathering the divergent species Aphaenops (Hydraphaenops) bucephalus, Aphaenops (Hydraphaenops) longicollis and sometimes, but not always, Aphaenops (Hydraphaenops) chappuisi (see Fig. 1a).
8.3. Aphaenops (Hydraphaenops) ehlersi group
Species in this group have pronotum and elytra glabrous [Aphaenops (Hydraphaenops) ehlersi (Figs. 3g, 8c), Aphaenops (Hydraphaenops) pecoudi] or slightly pubescent [Aphaenops (Hydraphaenops) bourgoini]. They share a similar shape of the median lobe of the aedeagus, which is curved with apical part narrowed and rounded (Fig. 6g), sickled mandibles and a straight labrum (Figs. 3g, 8c). This clade was already recovered in previous molecular studies (Faille 2006; Faille et al. 2010a).
A group of three tiny species from Ariège and Haute-Garonne.
8.4. Aphaenops (Hydraphaenops) minos group
All four species in this group have head and elytra pubescent and pronotum glabrous, median lobe of aedeagus straight, long and progressively sharpened to apex. Aphaenops (Hydraphaenops) hidalgoi, formerly assigned to Cerbaphaenops, unambiguously belongs to this group and is morphologically close to Aphaenops (Hydraphaenops) penacollaradensis (Faille 2006: 215). Such proximity is confirmed by the fact that A. hidalgoi and A. penacollaradensis are the only known hosts of Rhachomyces pyrenaeus Santamaria, a parasitic fungus of the Laboulbeniales group (Santamaria & Faille 2007).
A cryophilic group present at high altitudes up to almost 3,000 m (Faille 2006). It is the group with the largest distribution, from the Ariège Valley [Aphaenops (Hydraphaenops) minos] to Peña Collarada (Spain) and Gourette (France) [Aphaenops (Hydraphaenops) penacollaradensis]. The only species occurring at low altitudes is Aphaenops (Hydraphaenops) minos, described from the Lombrives cave in the Ariège Valley (France). This group corresponds to the Simaphaenops clade in QuÉinnec & Ollivier (2011).
Remarks
An alternative taxonomic choice regarding the large clade Hydraphaenops sensu novo would have been to keep the existing subgenera Cerbaphaenops [+ Aphaenops (Hydraphaenops) longicollis] and Simaphaenops as valid and restrict Hydraphaenops to just the Aphaenops (Hydraphaenops) ehlersi clade. Such a decision would have implied the creation of a new subgenus for the Aphaenops (Hydraphaenops) elegans + Aphaenops (Hydraphaenops) chaudoiri clade, without synapomophies supporting any of these three clades. Finally, the position of Aphaenops (Hydraphaenops) alfambrai, known only from the female holotype, is still questionable. Therefore, we chose the conservative option to include all these species in a large subgenus Hydraphaenops.
9. Subgenus Nafarroaphaenops subgen. n.
Type species
Aphaenops (Hydraphaenops) giraudi Ochs, 1938 (Ochs 1938: 26), by present designation (Figs. 3h, 6h).
Diagnosis
Body size variable (3.3–5.0 mm). Species with a “hydraphaenopsian” appearance: slender and completely [Aphaenops (Nafarroaphaenops) giraudi, Aphaenops (Nafarroaphaenops) navaricus] or partially [Aphaenops (Nafarroaphaenops) sobrarbensis] hairy (Fig. 3h). In spite of an important difference in size, the three species of the clade share a hairy head, oval elytra without pronounced humeral angles, a flattened mental tooth, pronotum much [Aphaenops (Nafarroaphaenops) giraudi, Aphaenops (Nafarroaphaenops) navaricus] or only slightly longer [Aphaenops (Nafarroaphaenops) sobrarbensis] than wide, striae hardly visible or lacking; penultimate labial palpomere tri- or quadrisetose. Aphaenops (Nafarroaphaenops) giraudi and Aphaenops (Nafarroaphaenops) navaricus share a similar shape of the ligula, with a salient tubercle [lacking in Aphaenops (Nafarroaphaenops) sobrarbensis] and median lobe of aedeagus with a rounded apex (Fig. 6h); in Aphaenops (Nafarroaphaenops) sobrarbensis, the outline of the median lobe is morphologically divergent from this model, very elongate and bisinuate dorsally, the apex acute and gradually curved upward. The minute species Aphaenops (Nafarroaphaenops) sobrarbensis, known from a single locality (Cueva de Aso in Sercué, Añisclo Valley, Spain) and from just two exemplars, is morphologically and genetically highly divergent and shares few characters with the two other species (A. giraudi and A. navaricus). Nevertheless, it is unambiguously related to these two species in all analyses; we therefore chose to be conservative and to include it in the same group. Further discoveries might fill the distribution gap between these three species and lead to taxonomic changes regarding A. sobrarbensis.
Etymology
Nafarroaphaenops refers to the Navarra area in euskera language, Nafarroa, Western Pyrenees. The three species of this subgenus occur in this region or in its vicinity.
Distribution
The three species belonging to the Nafarroaphaenops subgen. n. clade occur in the Western part of the Pyrenees: one in France [Aphaenops (Nafarroaphaenops) navaricus], one [Aphaenops (Nafarroaphaenops) sobrarbensis] in Spain. The third species, Aphaenops (Nafarroaphaenops) giraudi, is found on both slopes of the chain.
Fig. 8.
Differences in the head morphology in the clades Aphaenops s. str. [A. ochsi (a) vs. A. alberti (b)] and Hydraphaenops [A. ehlersi (c) vs. A. bucephalus (d)]. Scale bars: 2 mm.
10. Subgenus Pyreneotrechus subgen. n.
Type species
Geotrechus (Geotrechidius) aldensis Jeannel, 1955 (Jeannel 1955: 17), by present designation (Figs. 3i, 6i).
Diagnosis
Body size small (3.5–4.0 mm). Well characterized by the humeral setae forming a right angle, and median lobe of aedeagus long and slender, with sharpened apex. Elytra with intervals flat, striae hardly visible or absent, humeral angle faintly pronounced. Sagittal aileron well developed, parameres with two setae. Labial tooth rounded.
Etymology
The new name refers to the mountain chain where the group diversified, the Pyrenees (France and Spain).
Distribution
The only species of this subgenus is located in the Belesta area, eastern Ariège (France).
Remarks
Aphaenops (Pyreneotrechus) aldensis is the easternmost species of the group. It was already regarded as a particularly morphologically divergent species by its describer (Jeannel 1955).
11. Subgenus Riberaphaenops subgen. n.
Type species
Geotrechus holcartensis Genest, 1977 (Genest 1977: 281), by present designation (Figs. 4, 7).
Diagnosis
Small-sized: 2.8–3.8 mm. The three species in this subgenus share a similar and peculiar shape of the median lobe of the aedeagus, which is curved and enlarged in its apical part, with an upturned apex (Fig. 7). Prebasilar with six setae, labial tooth triangular, slightly protruding. Body pubescent, pronotum glabrous in Aphaenops (Riberaphaenops) picanyoli.
Etymology
Named to honour Ignacio Ribera, for his contribution to the knowledge of the cave beetle diversity of the Pyrenees.
Distribution
A clade of three rarely collected, tiny species from the Western Pyrenees. The type subspecies of Aphaenops (Riberaphaenops) holcartensis is known from a single female from Grotte d'Ayssaguer (Larrau), whereas the subspecies charlesi is known from a few exemplars from a cave in Arette (Fig. 4). Aphaenops (Riberaphaenops) picanyoli is the southernmost species of this clade, secluded in the conglomerates of Sierra de San Juan de la Peña (Huesca, Spain). The third species, Aphaenops (Riberaphaenops) dequaei, which was lacking for the molecular study, is only known from Cueva del Ponte in Abaurrea Alta (Navarra, Spain).
Discussion
As a result of a previous molecular phylogenetic analysis, Faille et al. (2010a) pointed out that a thorough systematic rearrangement of the classification of the Pyrenean clade of hypogean Trechini was needed, but the partial sampling in that study prevented any taxonomic action. The delimitation of the former three genera, Aphaenops, Hydraphaenops and Geotrechus, was the subject of many hypotheses (e.g., Jeannel 1920, 1922, 1926, 1941; Coiffait 1962; Casale & Laneyrie 1982; QuÉinnÉc & Ollivier 2011). The phylogeny presented here solves some of the main questions regarding the evolutionary history of the Pyrenean clade by gathering the species in one genus (Aphaenops) and many species groups, in order to avoid an artificial classification. The taxonomy proposed here is based on the combination of the molecular phylogeny with morphologically diagnostic character states independent of the convergent adaptive characters resulting from a subterranean lifestyle, as has been done for other lineages of hypogean ground beetles, such as the Trechini genus Orotrechus Müller [see discussion by Casale et al. (1991) when describing a highly modified cave species from Veneto]. Although the topology was highly consistent with the distribution of the species, identifying unambiguous morphological synapomorphies for each new subgenus was at a first glance quite challenging, and it was often a combination of characters that succeeded in defining the clades. The here-proposed taxonomy strengthens the congruence between the subgenera and species groups and their geographic distribution.
The most unexpected result of the phylogenetic analysis was the division of the former genus Geotrechus into eight subgenera, one of which, the monotypic Pyreneotrechus with the species A. (P.) aldensis, is sister to the whole radiation. This is the easternmost species of the radiation, and all the early splits in the history of the group concern eastern, non-troglobiomorphic species, stocky, without elongation of the appendages, and more common in the soil than in caves: the subgenera Ceretotrechus subgen. n., Aurigerotrechus subgen. n. and Argonotrechus subgen. n. This suggests an eastern origin of the whole Pyrenean lineage, an assumption also supported by the complete absence of the group in the Cantabrian chain, which is inhabited by other old lineages related to Trechus sensu lato (the Apoduvalius clade), is known to have acted as a refugium in the past, and hosts remarkable paleoendemic Trechini ground beetles such as Iberotrechus and Iberotrechodes (Jeannel 1913; Faille et al. 2021).
The subgenus Hydraphaenops sensu novo represents the bulk of the diversity of the “eastern clade” (sensu Faille et al. 2010a). The early splits of this clade are “hydraphaenopsian” species: two species from the Central Pyrenees [Aphaenops (Hydraphaenops) elegans + Aphaenops (Hydraphaenops) chaudoiri] and a group of cryophilic species [Aphaenops (Hydraphaenops) minos group]. The clade is found at high altitudes along the chain, from the Ariège Valley [Aphaenops (Hydraphaenops) minos, the only species found at low altitude, which was probably trapped following the glaciers retreat] to the Ossau Valley (France) and Río Aragón (Spain).
The troglobiomorphic species of the former genus Aphaenops belong to two main clades, one in the East (Aphaenops subg. Hydraphaenops sensu novo containing, among others, all the species previously grouped under the name Cerbaphaenops) and one in the West (Aphaenops sensu stricto).
Contrary to the previous views (QuÉinnec & Ollivier 2011), we found Geaphaenops to be unambiguously polyphyletic. Adaptation to an endogean way of life led convergently to the same stocky appearance in species of three different groups: the Aphaenops (Aphaenops) rhadamanthus group (all species), the Aphaenops (Aphaenops) eskualduna group [Aphaenops (Aphaenops) rebereti, Aphaenops (Aphaenops) cissauguensis] and the Aphaenops (Aphaenops) leschenaulti group [Aphaenops (Aphaenops) linderi].
Finally, the species of the former genus Hydraphaenops, which share a superficially convergent morphology (small appendages, elongated head with sickle mandibles), are now distributed within four subgenera containing most of the species at the base of the large clade Hydraphaenops sensu novo, a few in the three subgenera Geotrechidius [Aphaenops (Geotrechidius) pandellei complex], Dupreaphaenops subgen. n. [Aphaenops (Dupreaphaenops) vasconicus, Aphaenops (Dupreaphaenops) galani] and Nafarroaphaenops subgen. n. [Aphaenops (Nafarroaphaenops) navaricus, Aphaenops (Nafarroaphaenops) giraudiandAphaenops(Nafarroaphaenops)sobrarbensis].
Biogeographic patterns
The distribution of hypogean Trechini is heterogeneous along the Pyrenean chain. The highest diversity occurs on the northern slope (France), with 71 species found so far, 64 of which are endemic to this slope (Table 3; Fig. 9). Twenty-seven species occur on the southern slope (Spain), 20 of which are endemic to this slope. Most of the species are local endemics occurring in one department (France) or province (Spain) only. The peak of diversity is observed in Ariège, with 31 species known so far, 23 of which are strict endemics of the department. Only a few taxa are quite widespread, with strong geographic structuration of the populations across the range, highlighting the strong impact of geomorphology on the structure of the populations [see, e.g., Faille et al. (2015b) for A. cerberus]. The second richest area is the Pyrénées-Atlantiques department (also France), with 22 species but a proportionally lower number of endemic species (11), as this is the area of the chain with the highest number of species occurring on both slopes (Fig. 9). This might be explained by the decrease in altitude in the West, leading to more homogeneous ecological parameters and a less fragmented limestone cover on both slopes of the chain. Five of the 20 species of Aphaenops sensu stricto occur on both slopes of the Pyrenees (A. loubensi, A. ochsi, A. orionis, A. ludovici and A. eskualduna) (Table 3), whereas only one of the three species of Nafarroaphaenops (A. giraudi) occurs both in Spain and France. A trans-Pyrenean distribution is extremely rare in the speciose subgenus Hydraphaenops, as it has so far only been documented for the westernmost species of the subgenus: the cryophilic A. penacollaradensis, described from Peña Collarada (Huesca) but known just from a single specimen on the northern slope, from the Gourette area (Pyrénées-Atlantiques) (DuprÉ 1991; DuprÉ & Bourdeau 1994).
Fig. 9.
Diversity of hypogean Trechini by department (France) or province (Spain): number of species/number of endemic species. SP: Spain; FR: France. French departments: La: Landes; PA: Pyrénées-Atlantiques; HP: Hautes-Pyrénées; HG: Haute-Garonne; Ar: Ariège. Spanish provinces: Gu: Guipuzcoa; Na: Navarra; Hu: Huesca; Ll: Lleida; Ba: Barcelona; Gi: Girona. In brackets: [number of species per country/number of country endemics/number of endemics per single department or province].
Table 3.
Diversity and distribution of each subgenus by country.
Trans-Pyrenean sister relationships, a common occurrence in the Pyrenean lineage of subterranean Trechini
Whereas trans-Pyrenean species distributions are unusual, we could identify some examples of trans-Pyrenean sister relationships in hypogean Trechini. Such sister relationships between Spanish and French species in many clades was quite unexpected, as the axial chain of the Pyrenees was considered a barrier between species from the northern and southern slopes and a scenario of independent diversifications on each side of the chain was favoured. A striking example is found in the Aphaenops (Aphaenops) leschenaulti group, with the pair Aphaenops (Aphaenops) leschenaulti-Aphaenops (Aphaenops) linderi from the French Central Pyrenees sister to Aphaenops (Aphaenops) catalonicus, the southernmost species of Aphaenops sensu stricto, which reaches the Noguera Ribagorçana Valley on the Spanish side. A trans-Pyrenean distribution is also observed in the subgenus Riberaphaenops subgen. n., with the species Aphaenops (Riberaphaenops) holcartensis (France) vs. Aphaenops (Riberaphaenops) dequaei-Aphaenops (Riberaphaenops) picanyoli (Spain), and in some species of Leptodirini (Coleoptera, Leiodidae, Cholevinae), such as Bellesia espanyoli (Auroux & Bellés, 1974) from the Añisclo Valley in Huesca, a true Miocene relict closely related to Machaeroscelis Jeannel, 1924 from Ariège in France, the divergence between the two having occurred about 10.5 million years ago (Ribera et al. 2010).
Apart from these examples, other south versus north speciation events, with distributions perpendicular to the chain, have been identified in other subgenera: Geotrechidius, with Aphaenops (Geotrechidius) dumonti as the sister species of all members of the subgenus found on the French slope of the chain; Aphaenops (Dupreaphaenops) vasconicus-Aphaenops (Dupreaphaenops) sarpedon from the Arbailles Massif (Pyrénées-Atlantiques) vs. Aphaenops (Dupreaphaenops) galani from Guipúzcoa (in this case a distribution that did not have to overcome the geographical barrier of the Pyrenean Massif), or Aphaenops (Aphaenops) cissauguensis-Aphaenops (Aphaenops) rebereti vs. Aphaenops (Aphaenops) parvulus. In some cases, species were found at high altitude in the axial chain, acting as a transition link between the taxa from the northern and the southern slopes.
A few groups radiated parallel to the chain, the most diverse being the large Hydraphaenops clade, nearly exclusively found on the northern slope. But at the base of the clade is a clade of orophilic and cold-adapted species, the pair Aphaenops (Hydraphaenops) penacollaradensis-Aphaenops (Hydraphaenops) mouriesi, the most cryophilic species of the group, occurring in high altitude caves under snow. Finally, the presence of the clade Aphaenops (Hydraphaenops) elegans-Aphaenops (Hydraphaenops) chaudoiri in low altitude caves of the Central Pyrenees might not be regarded as an exception if we consider the high probability that the species Aphaenops (Hydraphaenops) alfambrai, known from a single female specimen found in a deep abyss located at ca. 2,100 m in the Central Pyrenees, is related to these two species.
This pattern suggests that the high altitude chain might have acted as a refugium from where cave beetles recolonized the low altitude karsts.
A similar biogeographical pattern occurs among the beetle tribe Leptodirini (Leiodidae), whose fauna also has a strong geographical structure, with a fundamental division between the eastern and western sectors of the Pyrenean Massif and a colonization of the subterranean environment that seems to have proceeded from the edges to the centre. Within each large zone, there seems to be a secondary division between the northern and southern slopes of the Pyrenees, which share practically no species from the subterranean environment, especially in the central part of the range. But there are close north-south faunal links that justify consideration of the entire massif as a biogeographical unit.
Three shapes, many histories
The phylogeny of the group reflects local diversifications nested within the distribution range of Pyrenean Trechini, and multiple convergence events within the Pyrenean lineage, evidenced by morphology as well as ecology or physiology [see, e.g., the convergent reduction of larval instars among the lineage inferred from the simplification of the ovaries by Faille & Pluot-Sigwalt (2015)].
The fact that none of the three morphologically well-characterized former genera Aphaenops, Hydraphaenops and Geotrechus sensu auct. was recovered as monophyletic illustrates the strong impact of the subterranean environment on morphology, which has led to convergent habitus for historically unrelated but ecologically similar species. The “Geotrechus shape” is shared by species scattered across the phylogeny; it should be regarded as plesiomorphic and resulting from more superficial ecologies, with most species occurring in the upper part of the karst or in the soil.
As already mentioned by Jeannel when dealing with all those species sharing an “hydraphaenopsian” morphology and at that time gathered in the subgenus Hydraphaenops: “Ce sous-genre réunit des lignées d'espèces assez disparates mais présentant un ensemble de caractères évolutifs […] Cet ensemble de caractères est en rapport avec un mode de vie particulier” [“This subgenus brings together lineages of quite disparate species but presenting a set of evolutionary characters […] This set of characters is related to a particular way of life”] (Jeannel 1948). The “hydraphaenopsian shape” is indeed shared convergently by species that could be regarded as fissuricolous, highly hygrophilic, adapted to the cracks of unreachable parts of the karst, which would also explain why they are, in most cases, extremely rare in caves, where they appear to occur accidentally only.
The plesiomorphic “geotrechoid shape” shared by species found preferentially in forest endogean environments is repeated in almost all clades; the dispersal of these elements through the most superficial compartments of the subterranean environment (the soil or deep litter layers in forest environments) during favourable paleoclimatic periods could explain the dispersion and speciation phenomena of the entire radiation: locally, they have given rise to various hypogean subclades with convergent adaptations to the various occupied habitats. Paradoxically, a result similar to that of the orthogenetic hypothesis of Jeannel (1950) is obtained: in all the clades containing troglobiomorphic taxa, the early splits concern “geotrechoid” species, with the late arrival of “aphaenopsian” and “hydraphaenopsian” taxa depending on the colonized habitat.
Conservation
The extension of the name Aphaenops to all the underground Trechini of the Pyrenees makes the legal texts, which only concern the species included in the genus Aphaenops as defined up to now, obsolete. A case-by-case assessment of the species on the basis of IUCN criteria, and in particular by integrating the notion of threat, is required to identify the taxa requiring appropriate conservation measures.
New replacement names
The new classification results in two homonymies, which can be solved as follows:
Aphaenops (Geotrechus) jeannelianus Faille, Fresneda & Bourdeau, nom. n. for Geotrechus jeanneli A. Gaudin, 1938 [nec Aphaenops jeanneli (Abeille de Perrin, 1905)].
Aphaenops (Aurigerotrechus) vandelianus Faille, Fresneda & Bourdeau, nom. n. for Geotrechus vandeli Coiffait, 1959 [nec Aphaenops vandeli Fourès, 1954].
A complete catalogue of the hypogean Trechini of the Pyrenees, following the new classification, is given in Appendix 1. The recognized species are listed from Serrano (2013) and Tronquet (2014), also considering later contributions (Faille et al. 2015a; Faille & Bourdeau 2022a, 2022b); the validity of the recognized subspecies was not tested here and will be the topic of future contributions.
Acknowledgements
We are grateful to the following people for their help in the field, for providing cave beetles from the Pyrenees, or for the loan of specimens from their private collections: F. Alfambra and the Grupo de Espeleología de Badalona (GEB), L. Auroux, P. Balart, A. Bedos, X. BellÈS, J. P. Besson†, M. Bof, F. Bréhier, H. Brustel, S. Cally, A. Casale, O. Caudron, J.Chauvin, S.Clément, J. Comas, O. Courtin, G. Corbaz, L. Deharveng, M. C. Delmasure, A. Dole, E. Dupré†, J. F. Etcheparre, F. Fadrique, C. Hernando, S. Huang, G. Jauzion†, B. Junger, V. Lefebvre, L. Rigou, N. Valla and the Groupe Spéléologique du Couserans (GSC), C. VAnderbergh. T. Deuve, A. Mantilleri, A. Taghavian (MNHN) and G. Masó (MZB) are warmly thanked for the loan of material under their care. We thank J. Schmidt, A. Casale and D. Whitmore for their thoughtful reviews of the manuscript.
We are also grateful to A. Bellersheim (SMNS) and S. Huang (MNHN) for providing us with some of the pictures illustrating this work. Collecting in the Ordesa National Park and Monte Perdido (Huesca, Spain) were carried out under a permit granted by INAGA (N. 24/2012/5229).
This work is dedicated to the memory of our friends P. Déliot, I. Ribera and E. Dupré, who were fascinated by the study of the cave fauna of the Pyrenees.
© Staatliches Museum für Naturkunde Stuttgart
References
Appendices
Appendix 1. List of the species of the genus Aphaenops sensu novo.
Genus Aphaenops Bonvouloir, 1862 (nomen protectum) sensu novo
Aphoenops Bonvouloir, 1862 (Bonvouloir 1862: 567) (nomen oblitum)
Aphaenops Bonvouloir, 1862 (Kraatz 1862: XII)
Cerbaphaenops Coiffait, 1962 (Coiffait 1962: 147), syn. n.
Cephalaphaenops Coiffait, 1962 (Coiffait 1962: 154)
Arachnaphaenops Jeanne, 1967 (Jeanne 1967: 20)
Geaphaenops Cabidoche, 1966 (Cabidoche 1966: 520), syn. n.
Pubaphaenops Genest, 1983 (Genest 1983: 309)
Simaphaenops Quéinnec & Ollivier, 2011 (QuÉinnec & Ollivier 2011: 210), syn. n.
1. Subgenus Aphaenops sensu novo
1.1. Group Aphaenops (Aphaenops) eskualduna
1.1.1. Aphaenops (Aphaenops) cissauguensis Faille & Bourdeau, 2008, subgen. comb. n. – France: Pyrénées-Atlantiques.
1.1.2. Aphaenops (Aphaenops) eskualduna Coiffait, 1959 – France: Pyrénées-Atlantiques; Spain: Huesca.
1.1.3. Aphaenops (Aphaenops) mensioni Lagar, 1976 – Spain: Huesca.
1.1.4. Aphaenops (Aphaenops) parvulus Faille, Bourdeau & Fresneda, 2010 – Spain: Huesca.
1.1.5. Aphaenops (Aphaenops) rebereti A. Gaudin, 1947, subgen. comb. n. – France: Pyrénées-Atlantiques.
1.2. Group Aphaenops (Aphaenops) jeanneli
1.3. Group Aphaenops (Aphaenops) leschenaulti
1.3.1. Aphaenops (Aphaenops) catalonicus Escolà & Canció, 1983 – Spain: Huesca.
1.3.2. Aphaenops (Aphaenops) leschenaulti Bonvouloir, 1862 – France: Hautes-Pyrénées.
1.3.3. Aphaenops (Aphaenops) linderi Jeannel, 1938, subgen. comb. n. – France: Haute-Pyrénées, Pyrénées-Atlantiques.
1.4. Group Aphaenops (Aphaenops) loubensi
1.4.1. Aphaenops (Aphaenops) abodiensis Dupré, 1988 – Spain: Navarra.
1.4.2. Aphaenops (Aphaenops) bessoni Cabidoche, 1962 – France: Pyrénées-Atlantiques.
1.4.3. Aphaenops (Aphaenops) loubensi Jeannel, 1953 – France: Pyrénées-Atlantiques; Spain: Huesca, Navarra.
1.4.4. Aphaenops (Aphaenops) valleti Casale & Genest, 1986 – Spain: Huesca
1.5. Group Aphaenops (Aphaenops) ochsi
1.5.1. Aphaenops (Aphaenops) fresnedai Faille & Bourdeau, 2011 – Spain: Huesca.
1.5.2. Aphaenops (Aphaenops) ochsi L. Gaudin 1925 – France: Pyrénées-Atlantiques; Spain: Huesca, Navarra.
1.6. Group Aphaenops (Aphaenops) rhadamanthus
1.6.1. Aphaenops (Aphaenops) baretosanus (Jeannel, 1941), subgen. comb. n. – France: Pyrénées-Atlantiques.
1.6.2. Aphaenops (Aphaenops) ludovici A. Gaudin, 1935, subgen. comb. n. – France: Hautes-Pyrénées; Pyrénées-Atlantiques; Spain: Navarra.
1.6.3. Aphaenops (Aphaenops) rhadamanthus (Linder, 1860), subgen. comb. n. – France: Hautes-Pyrénées, Pyrénées-Atlantiques.
2. Subgenus Argonotrechus subgen. n.
2.1. Aphaenops (Argonotrechus) orpheus (Dieck, 1869), comb. n. – France: Ariège, Haute-Garonne.
3. Subgenus Aurigerotrechus subgen. n.
3.1. Group Aphaenops (Aurigerotrechus) saulcyi
3.1.1. Aphaenops (Aurigerotrechus) andreae (Jeannel, 1920), comb. n. – France: Ariège.
3.1.2. Aphaenops (Aurigerotrechus) palei (Fourès, 1962), comb. n. – France: Ariège.
3.1.3. Aphaenops (Aurigerotrechus) saulcyi (Argod-Vallon, 1913), comb. n. – France: Ariège.
3.1.4. Aphaenops (Aurigerotrechus) vandelianus, Faille, Fresneda & Bourdeau, 2023 nom. n. for Geotrechus vandeli Coiffait, 1959 (nec Aphaenops vandeli Fourès, 1954 = Aphaenops (Hydraphaenops) vandeli Fourès, 1954) – France: Ariège.
3.1.5. Aphaenops (Aurigerotrechus) vanderberghi (Perreau & Quéinnec, 1987), comb. n. – France: Ariège.
3.2. Group Aphaenops (Aurigerotrechus) vulcanus sensu novo
3.2.1. Aphaenops (Aurigerotrechus) sulcatus (Coiffait, 1959), comb. n. – France: Ariège.
3.2.2. Aphaenops (Aurigerotrechus) vulcanus (Abeille de Perrin, 1904) comb. n. – France: Ariège.
4. Subgenus Ceretotrechus subgen. n.
4.1. Group Aphaenops (Ceretotrechus) delioti
4.1.1. Aphaenops (Ceretotrechus) delioti (Faille, Bourdeau, Bellès & Fresneda, 2015), comb. n. – Spain: Girona.
4.1.2. Aphaenops (Ceretotrechus) incantatus (Faille, Bourdeau, Bellès & Fresneda, 2015), comb. n. – Spain: Lleida.
4.2. Group Aphaenops (Ceretotrechus) ubachi
4.2.1. Aphaenops (Ceretotrechus) boumortensis (Faille, Bourdeau, Bellès & Fresneda, 2015), comb. n. – Spain: Lleida.
4.2.2. Aphaenops (Ceretotrechus) puigmalensis (Lagar, 1981), comb. n. – Spain: Girona.
4.2.3. Aphaenops (Ceretotrechus) seijasi (Español, 1969), comb. n. – Spain: Lleida.
4.2.4. Aphaenops (Ceretotrechus) ubachi (Español, 1965), comb. n. – Spain: Lleida.
4.2.5. Aphaenops (Ceretotrechus) victoriai* (Faille, Bourdeau, Bellès & Fresneda, 2015), comb. n. – Spain: Barcelona.
5. Subgenus Dupreaphaenops subgen. n.
5.1. Aphaenops (Dupreaphaenops) galani (Español, 1968), subgen. comb. n. – Spain: Guipúzcoa.
5.2. Aphaenops (Dupreaphaenops) sarpedon (Faille, Fresneda & Bourdeau, 2013), comb. n. – France: Pyrénées-Atlantiques.
5.3. Aphaenops (Dupreaphaenops) vasconicus Jeannel, 1913, subgen. comb. n. – France: Pyrénées-Atlantiques.
6. Subgenus Geotrechidius sensu novo
6.1. Aphaenops (Geotrechidius) blancheti (A. Gaudin, 1947), subgen. comb. n. – France: Hautes-Pyrénées.
6.2. Aphaenops (Geotrechidius) dumonti (Español, 1977), comb. n. – Spain: Huesca.
6.3. Aphaenops (Geotrechidius) gallicus (Delarouzée, 1857), comb. n. – France: Hautes-Pyrénées, Pyrénées-Atlantiques.
6.4. Aphaenops (Geotrechidius) gracilis (A. Gaudin, 1947), subgen. comb. n. – France: Pyrénées-Atlantiques.
6.5. Aphaenops (Geotrechidius) jeannelianus, Faille, Fresneda & Bourdeau, 2023 nom. n. for Geotrechus jeanneli A. Gaudin, 1938 – France: Hautes-Pyrénées.
6.6. Aphaenops (Geotrechidius) pandellei (Linder, 1859), subgen. comb. n. – France: Hautes-Pyrénées, Pyrénées-Atlantiques.
6.7. Aphaenops (Geotrechidius) soussieuxi (Perreau & Quéinnec, 1987), comb. n. – France: Landes.
7. Subgenus Geotrechus stat. n.
7.1. Aphaenops (Geotrechus) discontignyi (Fairmaire, 1867), comb. n. – France: Hautes-Pyrénées.
7.2. Aphaenops (Geotrechus) orcinus (Linder, 1859), comb. n. – France: Haute-Garonne, Hautes-Pyrénées.
7.3. Aphaenops (Geotrechus) serrulatus (Jeannel, 1946), comb. n. – France: Hautes-Pyrénées.
7.4. Aphaenops (Geotrechus) trophonius (Abeille de Perrin, 1872), comb. n. – France: Ariège, Haute-Garonne.
8. Subgenus Hydraphaenops sensu novo
8.1. Group Aphaenops (Hydraphaenops) chaudoiri
8.1.1. Aphaenops (Hydraphaenops) chaudoiri (Brisout de Barneville, 1867) – France: Hautes-Pyrénées.
8.1.2. Aphaenops (Hydraphaenops) elegans (A. Gaudin, 1946) – France: Hautes-Pyrénées.
8.1.3. Incertae sedis: Aphaenops (Hydraphaenops) alfambrai (Lagar, 1979) – Spain: Huesca.
8.2. Group Aphaenops (Hydraphaenops) crypticola sensu novo
8.2.1. Aphaenops (Hydraphaenops) aeacus (Saulcy, 1864), subgen. comb. n. – France: Hautes-Pyrénées.
8.2.2. Aphaenops (Hydraphaenops) bonneti Fourès, 1948, subgen. comb. n. – France: Ariège.
8.2.3. Aphaenops (Hydraphaenops) bouilloni Coiffait, 1955, subgen. comb. n. – France: Ariège.
8.2.4. Aphaenops (Hydraphaenops) bucephalus (Dieck, 1869), subgen. comb. n. – France: Ariège, Haute-Garonne.
8.2.5. Aphaenops (Hydraphaenops) carrerei Coiffait, 1953, subgen. comb. n. – France: Ariège.
8.2.6. Aphaenops (Hydraphaenops) cerberus (Dieck, 1869), subgen. comb. n. – France: Ariège, Haute-Garonne.
8.2.7. Aphaenops (Hydraphaenops) chappuisi Coiffait, 1955, subgen. comb. n. – France: Haute-Garonne.
8.2.8. Aphaenops (Hydraphaenops) colluvii Genest & Juberthie, 1983, subgen. comb. n. – France: Ariège.
8.2.9. Aphaenops (Hydraphaenops) corbazi* Faille & Bourdeau, 2022b, subgen. comb. n. – France: Haute-Garonne.
8.2.10. Aphaenops (Hydraphaenops) crypticola* (Linder, 1859), subgen. comb. n. – France: Haute-Garonne, Hautes-Pyrénées.
8.2.11. Aphaenops (Hydraphaenops) hortensis Fourès, 1954, subgen. comb. n. – France: Ariège.
8.2.12. Aphaenops (Hydraphaenops) hustachei Jeannel, 1917, subgen. comb. n. – France: Hautes-Pyrénées.
8.2.13. Aphaenops (Hydraphaenops) jauzioni Faille, Déliot & Quéinnec, 2007, subgen. comb. n. – France: Haute-Garonne.
8.2.14. Aphaenops (Hydraphaenops) laurenti Genest, 1983, subgen. comb. n. – France: Ariège.
8.2.15. Aphaenops (Hydraphaenops) longicollis Joffre, 1931 – France: Hautes-Pyrénées.
8.2.16. Aphaenops (Hydraphaenops) mariaerosae Genest, 1983, subgen. comb. n. – France: Ariège.
8.2.17. Aphaenops (Hydraphaenops) michaeli Fourès, 1954, subgen. comb. n. – France: Ariège.
8.2.18. Aphaenops (Hydraphaenops) parallelus* Coiffait, 1954, subgen. comb. n. – France: Ariège, Haute-Garonne.
8.2.19. Aphaenops (Hydraphaenops) pluto (Dieck, 1869), subgen. comb. n. – France: Ariège.
8.2.20. Aphaenops (Hydraphaenops) pseudocrypticola Coiffait, 1947, subgen. comb. n. – France: Hautes-Pyrénées.
8.2.21. Aphaenops (Hydraphaenops) riberai* Faille & Bourdeau, 2022a, subgen. comb. n. – France: Haute-Garonne.
8.2.22. Aphaenops (Hydraphaenops) sinester Coiffait, 1959, subgen. comb. n.- France: Ariège.
8.2.23. Aphaenops (Hydraphaenops) sioberae Fourès, 1954, subgen. comb. n. – France: Ariège.
8.2.24. Aphaenops (Hydraphaenops) tiresias (Piochard de La Brûlerie, 1872), subgen. comb. n. – France: Ariège, Haute-Garonne.
8.2.25. Aphaenops (Hydraphaenops) vandeli Fourès, 1954, subgen. comb. n. – France: Ariège.
*Remark: the species A. crypticola and sister taxa were partially revised recently. The species A. crypticola is located between the Aure valley to the West and the Garonne valley to the East. All the populations located between the Garonne valley and the Portet d'Aspet area belong to Aphaenops parallelus (Faille & Bourdeau 2022a).
8.3. Group Aphaenops (Hydraphaenops) ehlersi sensu novo
8.3.1. Aphaenops (Hydraphaenops) bourgoini Jeannel, 1946 – France: Ariège, Haute-Garonne.
8.3.2. Aphaenops (Hydraphaenops) ehlersi (Abeille de Perrin, 1872) – France: Ariège, Haute-Garonne.
8.3.3. Aphaenops (Hydraphaenops) pecoudi A. Gaudin, 1938 – France: Ariège.
8.4. Group Aphaenops (Hydraphaenops) minos
8.4.1. Aphaenops (Hydraphaenops) hidalgoi (Español & Comas, 1985), subgen. comb. n. – Spain: Huesca.
8.4.2. Aphaenops (Hydraphaenops) minos (Linder, 1860), subgen. comb. n. – France: Ariège.
8.4.3. Aphaenops (Hydraphaenops) mouriesi (Genest, 1983), subgen. comb. n. – France: Ariège.
8.4.4. Aphaenops (Hydraphaenops) penacollaradensis (Dupré, 1991), subgen. comb. n. – France: Pyrénées-Atlantiques; Spain: Huesca.
9. Subgenus Nafarroaphaenops subgen. n.
9.1. Aphaenops (Nafarroaphaenops) giraudi Ochs, 1938, subgen. comb. n. – France: Pyrénées-Atlantiques; Spain: Navarra.
9.2. Aphaenops (Nafarroaphaenops) navaricus Coiffait & A. Gaudin, 1950, subgen. comb. n. – France: Pyrénées-Atlantiques.
9.3. Aphaenops (Nafarroaphaenops) sobrarbensis (Lagar & Hernando, 1987), subgen. comb. n. – Spain: Huesca.
10. Subgenus Pyreneotrechus subgen. n.
11. Subgenus Riberaphaenops subgen. n.
11.1. Aphaenops (Riberaphaenops) dequaei (Dupré, 1988), comb. n. – Spain: Navarra.
11.2. Aphaenops (Riberaphaenops) holcartensis (Genest 1977), comb. n. – France: Pyrénées-Atlantiques.
11.3. Aphaenops (Riberaphaenops) picanyoli (Español & Escolà, 1983), comb. n. – Spain: Huesca.
Appendix 2. Summary of the main morphological characters of each subgenus of Aphaenops sensu novo. The characters defining the subgenera are listed in the main text.
Glabrous body and sternites with 2 symmetrical setae
Mc1 implanted very far from the base of the elytra, body glabrous, tm1 lower than tm2...................................Pyreneotrechus, Ceretotrechus, Aurigerotrechus
Mc1 implanted close to the base of the elytra, elytra only slightly pubescent Argonotrechus
Size >5mm, Tm1 always higher than tm2, elytra without striae Aphaenops (exception: A. alberti has a pubescent head)
Pubescent sternites with 2 symmetrical setae
Body fully hairy
Tm1 lower than tm2 Geotrechus-Riberaphaenops-Nafarroaphaenops
Tm1 higher than tm2 Dupreaphaenops
Elytra glabrous, head pubescent Geotrechidius
Head pubescent, pronotum glabrous Hydraphaenops
