Flourishing in subterranean ecosystems: Euro-Mediterranean Plusiocampinae and tachycampoids (Diplura, Campodeidae)

Diplura is a group of entognathous hexapods, often considered a sister group to insects. They play an important role in recycling organic matter in soil and subterranean terrestrial ecosystems. The Campodeidae is the most diverse family, divided into four subfamilies. The subfamily Plusiocampinae has a subterranean life-style with many species distributed in the Euro-Mediterranean area. The incertae sedis tachycampoids (“lignée Tachycampoïde”) is a group within the family Campodeidae that share with the Plusiocampinae a strong preference for subterranean habitats and several morphological characters, such as slender body shape, elongated appendages, considerable increment in the number of antennomeres and cercal articles, and complexity of sensorial structures. The present monograph provides a taxonomic revision of the subfamily Plusiocampinae and the genera belonging to the tachycampoid lineage from Europe and the Mediterranean region. It comprises detailed morphological descriptions and illustrations together with data on the habitats and distributions of 87 species, 10 subspecies and 11 affinis forms. Seven new species are described among those, namely: Plusiocampa (Plusiocampa) apollo Sendra, Giachino & Vailati sp. nov., P. (P.) chiosensis Sendra & Gasparo sp. nov., P. (P.) dublanskii Sendra & Turbanov sp. nov., P. (P.) hoffmanni Sendra & Paragamian sp. nov., P. (P.) rhea Sendra sp. nov., P. (P.) ternovensis Sendra & Borko sp. nov. and P. (Venetocampa) ferrani Sendra & Delić sp. nov.


Introduction
Diplura is a group of eyeless entognathous hexapods, often considered a sister group to insects, which colonize terrestrial habitats, presenting a tracheal system, rudimentary Malpighian tubules and sperm transfer via a spermatophore (Beutel et al. 2017;Denis 1949). About 1000 extant dipluran species are named and described in 10 dipluran families. Half of this diversity belongs to the Campodeidae (Condé 1955a;Pagés 1959;Sendra 2015). The family Campodeidae is characterized by soft pluriarticular cerci European Journal of Taxonomy 591: 1-138 (2020) sides of the Atlantic and the nine American and eight Euro-Mediterranean species clearly indicate a disjunct distribution of the group. Some species of Oncinocampa, Paratachycampa and Tachycampa show amphi-Atlantic distributions (Bareth & Condé 1981;Sendra et al. 2016).
A taxonomic revision of most plusiocampine and tachycampoid genera from the Euro-Mediterranean region is provided (see complete list of previously published reports in Table S1 in Supplementary Material), together with the description of seven new species. The present monograph also provides detailed descriptions and illustrations of the morphological characters, as well as data on habitats and distribution maps, based on material from several collections and freshly sampled specimens.

Material and methods
During the last decade, an enthusiastic group of friends and colleagues, speleologists, biospeleologists and biologists have gathered many samples of Plusiocampinae and tachycampoids. This material was sampled in soil and hypogean habitats, including the deepest dipluran ever collected at 1180 m below the surface of the Kanin Mountains, in Slovenia. This large sampling effort extended over the Euro-Mediterranean region, including many Mediterranean islands. It resulted in a total of 4243 specimens from 182 localities, most of them in carbonate caves. Details on the specimens collected for each species are given in the ʻHabitat and distributionʼ sections, including all localities of the Euro-Mediterranean species. A complete list of collecting events, organized by taxon, is presented in Table S2 in the Supplementary Material. Specimens were washed using distilled water, mounted on slides in Marc André II solution and studied under a phase-contrast microscope (Leica DMLS). The illustrations were made using a drawing tube. Measurements were taken with an ocular micrometer. The specimens mounted 'in toto' were measured from the distal macrosetae on the frontal process to the abdominal supra-anal valve. For scanning electron microscopy (SEM) some specimens were critical point-dried, coated with palladium-gold and studied under a Hitachi S-4100 SEM.
The identification keys to genera, subgenera and species of Plusiocampinae and tachycampoids were generated from a DELTA database (Dallwitz 2005) and modified to improve readability. For each taxon, a diagnosis has been generated, as well as a habitat and distribution section. Taxonomic notes and character illustrations are provided for the seven newly described species.

Habitat and distribution
Subterranean species found in 11 caves around the Castilian-Valencian Branch of the Iberian Mountain Range and its border with the northwest of the Pre-Baetic Mountains, eastern Iberian Peninsula.

Habitat and distribution
Soil-dwelling species known from the type locality in Strongoli, Calabria, southern Italian Peninsula, and northern Macedonia.

Habitat and distribution
Subterranean species widespread in the Jura karst mountains between France and Switzerland, where it is found in 18 caves (Fig. 210).

Remarks (Figs 1-2)
The study of many specimens collected in 6 new caves (see Table S2 in Supplementary Material) allowed us to complete Condé's diagnosis, as well as to supplement it with some minor taxonomic details. Medial antennomeres with 10-12 gouge sensilla 40-50 µm long. End of metathoracic leg reaches end of abdomen; calcars covered with barbs; subapical setae with thin barbs almost from base up to twothirds of length. Stylus with an apical seta with a few thin barbs and a large, thick basal tooth, medial and subapical setae covered with thin barbs. Male appendages with up to 60 glandular a 2 setae and 20 a 1 glandular setae (Fig. 1); female appendages with up to 18 a 1 glandular setae. Spermatozoid fascicle wheels with 2 turns of 140-160 µm long and up to 4 µm wide filament (Fig. 2).

Habitat and distribution
Subterranean species found in eight caves in eastern Sardinia (Fig. 210).
Plusiocampa Silvestri, 1912 Plusiocampa Silvestri, 1912: 141. Diagnosis (Silvestri 1912;Condé 1955a;Sendra & Weber 2018) Apparently smooth epicuticle, usually reticulated at high magnification, rosetta pores absent. Head with a frontal process with or without tuberculate setae. In non-troglomorphic species, cupuliform organ with four or five spheroidal olfactory chemoreceptors with polygonal net, with pore surface made by at least one cup-shaped fold and a central structure ending in a terminal pore. In troglobiomorphic species, spheroidal olfactory chemoreceptor with more folds in spiral, radial or other complex shape and a more visible polygonal net with pore surface. Sensillum of third antennomere in ventral position. Meso-and metathorax with a few macrosetae but frequently with medial anterior, lateral anterior, lateral posterior and medial posterior (exceptionally medial intermediate and lateral intermediate) macrosetae. Femur with one to five dorsal macrosetae; tibia with one to three ventral macrosetae. Elbow-like claws with usually large lateral crests and setiform lateral processes, rarely with a few barbs on proximal part. Abdomen with lateral anterior and posterior macrosetae and never with medial anterior macrosetae. Sternal macrosetae: sternite I with 6+6 up to 60 macrosetae; sternites II-VII with 4+4 to up to 14+14 macrosetae; sternite VIII with 2+2 up to 4+4 macrosetae. Secondary sexual differences in shape of first urosternite appendages and number of glandular setae.

Habitat and distribution
This is the most diverse genus of Plusiocampinae, with a clear preference for the subterranean ecosystems (Condé 1955a;Sendra & Weber 2018). It has 72 species (including the seven new ones described here) and 10 subspecies, distributed around the Mediterranean Basin . The exceptions are three Chinese species considered representatives of Plusiocampa by Silvestri (1931a), Condé (1993a) and Sendra et al. (2012a): P. sinensis Silvestri, 1931, P. lipsae Condé, 1993 andP. kashiensis Chou &Tong, 1980. Nevertheless, these species must be removed from Plusiocampa due to the macrosetal formula on urosternites II to VIII.
Diagnosis (Paclt 1957;Condé 1996) Dydimocampa shares with Plusiocampa s. str. the same taxonomic features, with the exception of the two dorsal femoral macrosetae. This fact, together with their distribution patterns, suggests that Dydimocampa is an artificial subgenus based on a single apomorphic feature that has probably appeared several times in Plusiocampa s. str.

Habitat and distribution
The three species treated here are cave-dwellers with a subterranean life-style and they are distributed in three disjunct karst areas in Europe (Fig. 211).

Habitat and distribution
Subterranean species inhabiting the Movile Cave, Southern Dubrudja, Romania.

Remarks
The study of four specimens, a juvenile and 3 females, collected in three caves (see Table S2 in Supplementary Material) allowed a comparison with the species description, but new topotype material is needed to clarify the taxonomic status of this species (Table 1). The epicuticle of dorsal sclerites is reticulate when observed in high magnification (Fig. 6). Antennae with 34 and 35 antennomeres in two adults, and 40 in the juvenile; adult medial antennomeres 1.6 × as long as wide, apical antennomere 2.5 × as long as wide; one distal whorl with 20-22 gouge sensilla in each medial and distal antennomere, 36-38 µm in length (Fig. 4). Cupuliform organ occupies 1/5 of total length of last antennomere, with more than ten spheroidal olfactory chemoreceptors with a central column unfolded in complex expansions with a visible polygonal net with porous surface (Fig. 3). Protruding frontal process with abundant tubercular setae (Fig. 5). Pronotum with 3+3 la macrosetae (2+2 la in original description). Unequal claws (1.4-1.5) with large lateral crests (Fig, 7), posterior claw with a large backward overhang; short lateral anterior pretarsal processes, less than half length of claw, and long lateral posterior pretarsal anterior process overpassing end of claw, as described in type form. Calcars with two rows of long barbs almost from base; smooth subapical tarsal setae. Urotergites with important differences from type form: 2+2 (3+2) la and 4+4-5+5 post on urotergites VI-VII; 6+6 post on urotergite VII; 9+9 post macrosetae on abdominal segment IX (undescribed in type form). Stylar setae with a few long, thin barbs. Urosternite I with 7+7, urosternites II-VII with 6+6, urosternite VIII with 2+2 macrosetae (Fig. 8).
Cerci 1.9 × as long as body, with only 6 articles plus base.

Habitat and distribution
Subterranean species found in four caves, including the type locality in the I-El Koba (= Kizil-Koba, Krasnaya) Сave in the Crimean Mountains. The occurrence of such a distribution for P. (D.) evallonychia Diagnosis (Sendra & Weber 2018) Mesothoracic and metathoracic femora with five dorsal macrosetae, up to three on prothoracic femur; presence of a narrow area of glandular g 1 setae in adult females.

Habitat and distribution
Monotypic subgenus known only from a single cave in southwest Germany (Fig. 211).

Habitat and distribution
Within humid soils and MSS, but with a preference for the deep subterranean spaces found in caves, including the deepest caves in the world. The 60 species and 9 subspecies of this subgenus are wellspread around the Euro-Mediterranean region, from Southern Europe, including a small karst area in North Africa (Kabylian Mountains, Tell Atlas), throughout south of Central to Southeastern Europe and also reaching some spots in the Anatolian and Crimean peninsulas and Western Caucasus (Fig. 211). Condé, 1947 Plusiocampa affinis Condé, 1947a: 25, fig. 4.

Habitat and distribution
This species is only known from Županska pećina, Lubnice, Berane Municipality, Montenegro.  Table 2 Etymology The specific name ʻapolloʼ is proposed since the Parnassos Mountain, its type locality, is the home of the divinity ʻApolloʼ.

Description
Body. Body length 4.5 to 6.1 mm (females) and 5.0 to 6.4 mm (males). Epicuticle smooth under optical microscope; body with thin, middle-sized clothing, covered or not by a few thin barbs.
Head. Two intact antennae in a 5.6 mm long female paratype with 28 antennomeres and a 5.1 mm long female paratype with 32 antennomeres, in both shorter than body length ( Table 2). Small subcylindrical sensillum of third antennomere located in ventral position between c and d macrosetae. Central antennomeres 1.8 × as long as wide, apical antennomere 2.0 × as long as wide. Cupuliform organ occupying ¼ of total length of apical antennomere, with 8-9 complex olfactory chemoreceptors. Gouge sensilla 30-38 µm long, in a single distal whorl of 16-18 sensilla on each medial and distal antennomere. Frontal process plain, with non-tubercular setae and macrosetae with a few barbs along distal half; macrosetae along line of insertion of antennomere and x setae longer than other macrosetae (a / i / p / x with relative lengths of 40 / 48 / 37 / 68 in holotype). Suboval labial palps with a small, coniform lateroexternal sensillum, with two guard setae, up to 9 setae on anterior border and up to 190 neuroglandular setae.
Secondary Sex cHaracTerS. Male urosternite I ( Fig. 11) with up to 180 glandular g 1 setae arranged in up to five rows, with enlarged subcylindrical appendages each bearing up to 52 glandular a 1 setae. Female appendages slightly thinner, with up to 38 glandular a 1 setae.

Remarks
The studied material allowed us to complete the above description. The complete antennae of a female from Jama 1 v Kanjaducah show 23 antennomeres with five simple olfactory chemoreceptors within the cupuliform organ; it has a distal whorl of 8-11 gouge sensilla that are 25 µm long. All specimens show a simple frontal process with non-tubercular setae; smooth subapical tarsal setae; abdominal segment IX with 8+8 post macrosetae; urosternite I of male with a narrow area of up to 80 glandular g 1 setae arranged in two or three rows; subcylindrical appendages with up to 12 glandular a 1 setae; females with subcylindrical appendages as in male, with up to 9 glandular a 1 setae. Nevertheless, the large distance from the type locality casts serious doubts regarding the correct identification of this rare species.

Habitat and distribution
Hypogean species found in two geographically distant karst regions, the Lyashkata Peshtera Cave, Balkan Mountains in Bulgaria, and two caves in the Slovenian Dinaric Mountains.

Remarks
SEM observations have shown several taxonomical features to complete the original description

Habitat and distribution
Subterranean species found in 11 caves and at one edaphic site in the Île Saint-Honorat caves around the Western Alps, in the mountain reliefs near the Mediterranean coast in the Provence Alps, France. Condé, 1961 Plusiocampa bonadonai lanzai Condé, 1961: 399.

Habitat and distribution
Subterranean subspecies found in a cave of Valais (Switzerland) as well as in two caves in Brescia and Toscana (Italy), around the Western Alps. Condé & Poivre, 1982 Plusiocampa bonadonai pavani Condé & Poivre, 1981: 171.

Habitat and distribution
Subterranean species found in three caves in the southern reliefs of France, west of the Rhône River, and in 34 caves distributed from the Central Pyrenees to the Pre-Pyrenees without reaching the Ebro Basin.

Remarks (Figs 24-35)
One male of P. (P.) bonneti bonneti from Cova Mora (San Juan de la Peña, Huesca, Spain) and six specimens of P. (P.) bonneti condei from Cova Toll (Moià, Barcelona, Spain) (see Table S2 in Supplementary Material) were used for SEM to remark on some features that are difficult to observe under the optical microscope. In P. (P.) bonneti bonneti, the first urosternite shows very long subtrapezoidal appendages with a large area of glandular a 2 setae and a large area of glandular g 1 setae, with the surface covered by barbed clothing setae and well-barbed macrosetae (

Habitat and distribution
Subterranean subspecies found in 35 caves in the Eastern Pyrenees and the northern part of the Catalan Mediterranean Mountain System.  Plusicampa bonneti deharvengi : 128, figs 1-2, table 1.

Habitat and distribution
Hypogean species, only found in Lóczy Cave, Balatonfüred, in the Balaton Uplands, southern Transdanubian Mountains, Hungary.

Habitat and distribution
Subterranean species inhabiting two caves in Eivissa and four caves in Formentera, two of the Balearic Islands. Plusiocampa (P.) aff. breuili is only known from a cave in the eastern Baetic Mountains, southeastern Iberian Peninsula. Silvestri, 1931 Figs 42-43 Plusiocampa bulgarica Silvestri, 1931b: 103, figs vi-viii.

Remarks
The study of 38 specimens collected from two new caves (see Table S2 in Supplementary Material) allowed the addition of information to the diagnosis, including the observation of the pretarsal structures .

Habitat and distribution
Subterranean species found in 16 caves in the Balkan and Rhodope Mountains, Bulgaria.

Remarks
One male and one female of P. (P.) caprai from Babja jama (Slovenia) have been studied. However, two females collected from an MSS habitat in Corinthia (Peloponnese Peninsula) (see Table S2 in Supplementary Material) appear to be very closely related to P. (P.) caprai, although the substantial geographical distance between these two areas and the observation of only females cast doubts on this specific attribution. Furthermore, all antennae and cerci are broken. The frontal process shows a protrusion and bears tubercular setae.

Habitat and distribution
Hypogean species inhabiting subterranean and soil habitats, found in six caves, one mine and two soil and MSS habitats in the Austrian, Italian, Slovenian and Swiss Alps. Paratypes GREECE • 2 ♂♂; same collection data as for holotype; Coll. AS.

Description
Body. Body length 4.4 and 4.9 mm (males, paratypes) and 7.8 mm (female, holotype). Epicuticle smooth under optical microscope; body with sparse thin, long clothing, covered or not by a few thin distal barbs.
Head. Holotype with two intact antennae of 54 antennomeres, 14.8 mm long. Small coniform sensillum of third antennomere located in ventral position between c and d macrosetae. Central antennomeres 3.8 × as long as wide, apical anntenomere 3.6 × as long as wide. Small cupuliform organ occupying 1/9 of total length of apical antennomere, with 6-7 complex olfactory chemoreceptors. Thin and long gouge sensilla (44-47 µm long) in a single distal whorl of 10-13 sensilla on each medial and distal antennomere. Frontal process developed, with tubercular setae and macrosetae with thin barbs. Three macrosetae along line of insertion of antennae poorly differentiated, only anterior one with 1-2 thin apical barbs; x setae longer than these macrosetae, with a couple of thin apical barbs (Fig. 44). Suboval labial palps with latero-external sensillum larger than sensillum of third antennomere, with two guard setae, up to 12 setae on anterior border and up to 130 neuroglandular setae.
cerci. One complete cercus in holotype with eight articles in addition to basal article, 19.70 mm long (Table 4), 2.53 mm longer than body length; articles show whorls of long macrosetae covered by thin barbs along distal two-thirds, combined with whorls of smooth, thin setae shorter than macrosetae.
Secondary Sex cHaracTerS. Female urosternite I ( Fig. 45) with enlarged subcylindrical appendages, each bearing up to 16 glandular a 1 setae in a distal area. Male urosternite I (Fig. 46) without glandular g 1 setae, with moderated large subcylindrical appendages thicker than those of female, each bearing up to 33 glandular a 1 setae.

Phyletic affinities, habitat and distribution
Although P. (P.) chiosensis sp. nov. has medial posterior macrosetae on the mesonotum and metanotum (sometimes absent in one or two heminota), as do many previously described species of Plusiocampa s. str., a similar reduction in the number of lateral anterior and lateral posterior macrosetae on the mesonotum and metanotum is present in another troglomorphic species, P. (P.) glagra from continental Greece (Condé 1984a). Plusiocampa (P.) chiosensis sp. nov. also shares a couple of noticeable taxonomical features with P. (P.) glabra in their subequal claws and the number of urosternal macrosetae. Nevertheless, the presence of 1+1 lateral anterior macrosetae on the mesonotum, the more abundant macrosetae on all urotergites, including the eighth abdominal segment, and the absence of glandular g 1 setae in males in P. (P.) chiosensis sp. nov. distinguish it from P. (P.) glabra.
Plusiocampa (P.) chiosensis sp. nov. is only known from one cave and occupies the deep subterranean spaces, showing highly troglomorphic features (elongation of appendages, antennomeres and articles, and the strengthening of sensorial equipment of the antennae). subtrapezoidal appendages with an area of glandular a 2 setae; female with subcylindrical appendages with glandular a 1 setae. Spermatozoid fascicles 60-65 µm in diameter and 25-30 µm wide, wheels with 2½-3 turns of 650 µm long and 13 µm diameter filament.

Remarks
The study of one female from Puech Cave, Grands Causses, France (see Table S2 in Supplementary Material) has allowed us to supplement the former description, including regarding the presence of only 1+1 lp metanotal macrosetae.

Habitat and distribution
Subterranean species, well-spread around the Grands Causses, where it is found in eight caves, living alongside the troglobite P. (P.) balsani.

Habitat and distribution
Subterranean subspecies inhabiting one cave, Grotte Scaloria, Manfredonia, Gargano, Italian Peninsula, near the type locality.

Description
Body. Body length 2.7 mm. Epicuticle smooth under optical microscope but with a reticulate surface under SEM (Fig. 47); body with sparse thin and middle-sized clothing setae with 1-3 thin distal barbs.
Head. Two intact antennae with 35 antennomeres, longer than body length (3.2 mm); thin subcylindrical sensillum on third antennomere in ventral position between macrosetae d and e; central antennomeres 2.1 × as long as wide, apical antennomere 3.0 × as long as wide; cupuliform organ occupying 1/7 of its length, with nine complex olfactory chemoreceptors; gouge sensilla 40-50 µm long in a single whorl of 10-12 sensilla on each medial and distal antennomere; a small, thin subcylindrical sensillum on third antennomere. Non-protruding frontal process with very slightly tubercular frontal macrosetae. Frontal process plain, with very slight tubercular frontal macrosetae; macrosetae along line of insertion of antennomere and x setae similar in length and with a few distal barbs (a / i / p / x with relative lengths of 29 / 19 / 24 / 25). Small suboval labial palps with a large subcylindrical sensillum, two guard setae, five normal setae and up to 20 neuroglandular setae.

Remarks
Body length 2.8 mm. It shows some differences from the type form in the number of macrosetae on the pronotum (1+2 la 2,3 ), metanotum (1+1 la), urotergite IV (without la macrosetae), urotergite V (without la and 1+1 post 1 ), urotergite VI (1+1 la, 2+2 post 1,2 ), urotergite VII (2+2 la 2,3 , 2+2 post 1,2 ), urotergite VIII (4+4 post) and abdominal segment IX (7+7 post).  (Condé 1954a;Neuherz 1984) and P. (P.) fagei from caves on Mallorca (Condé 1955b) share two important taxonomic characters with P. (P.) dublanskii sp. nov.: the distinctly unequal claws with large lateral crests and an evident backward overhang on the posterior claw, and the presence of medial posterior macrosetae on the mesonotum and metanotum. Nonetheless, the absence of ventral tibial macrosetae or the extremely unequal claws with unequal lateral pretarsal processes suggest a completely different relationship with the unclear subgenus Venetocampa from the Veneto region, northern Italian Peninsula. These new troglomorphic taxa live in two separated karst regions in the north (Crimea) and the east (Western Caucasus) of the Black Sea. The important differences between the two studied specimens are remarkable, in particular the number and distribution of the macrosetae on the urotergites and abdominal segment, something that should be reviewed in the future with further samples. Ionescu, 1955 Plusiocampa elongata Ionescu, 1955: 43, figs 18-19.

Habitat and distribution
Subterranean species found in nine caves around the Carpathian Mountains in Romania; P. (P.) aff. elongata has only been found in one cave, the Peştera Cloşani cave.

Remarks
The study of five specimens from two caves in Slovenia and Trieste, Italy, and one from Faedo San Michele, Trento, Italy (see Table S2 in Supplementary Material) allowed the addition of information to the diagnosis.

Habitat and distribution
Hypogean species found in caves and frequently in soil. A total of 20 localities are reported from around Central Europe, from the Czech Republic and Slovakia to the Italian and Dinaric Mountains, reaching Croatia and Bosnia and Herzegovina towards the east and France towards the west, where it has been found in garden soils. This species is often found in urban soils, e.g., at ca 20 sites in Vienna (Christian 1992). The presence of P. (P.) cf. exsulans on the Anatolian Peninsula (Sendra et al. 2006) must be confirmed. Condé, 1955 Figs 51-52 Plusiocampa fagei Condé, 1955b: 129, figs 3d, 4. Diagnosis (Condé 1955b Male with a narrow area of glandular g 1 setae and very long cylindrical appendages with glandular a 1 setae; female with thin subcylindrical appendages with glandular a 1 setae.

Remarks
Two specimens from Cova Sa Gleda, Manacor, Mallorca (see Table S2 in Supplementary Material) were used for SEM to look at some features that are difficult to observe under an optical microscope, such as their thin gouge sensilla, 48-50 µm long with an external transversal striped surface (Figs 51-52).

Habitat and distribution
Subterranean species inhabiting 19 caves in Mallorca, Balearic Islands, mainly in the Tramuntana mountain chain on the north of the island.

Remarks
The studied material (see Table S2 in Supplementary Material) from MSS habitats was collected from inland Greece. Three specimens from Évia show variability in the number of post macrosetae on the third urotergite; they have 2+1, 2+2 and 3+3 post macrosetae, showing the dubious value of the subspecies P. (P.) festae coi. In addition, a juvenile from Montes Orno, Crete, has also been studied and it matches in all chaetotaxic characters with P. (P.) festae festae. In conclusion, we suggest that P. (P.) festae coi should be synonymized with the nominate subspecies.

Habitat and distribution
Soil-dwelling species previously found on Karpathos and Leros, islands of the Dodecanese Archipelago; also collected in endogean environments at two sites on Crete and at a locality near Izmir, Anatolia, Turkey. It seems to inhabit MSS, where it has also been found at 14 localities in continental Greece. Bareth & Condé, 1984 Plusiocampa friulensis Bareth & Condé, 1984: 136, fig. 2.

Habitat and distribution
Subterranean species endemic to the isolated karst of Sierra de Gádor, in the Peni-Baetic System, southeastern Iberian Peninsula. It is known from seven natural caves and one mine.

Plusiocampa (Plusiocampa) grandii
Diagnosis (Silvestri 1933b;Condé 1954a)  Plusiocampa (Plusiocampa) aff. grandii Silvestri, 1933 Differential diagnosis against the type form Observation of a single female from Inamila Cave in Evia, Greece (Coll. AS). It shows remarkable differences from the type form, such as the more anterior insertion position of mp mesonotal and metanotal macrasetae and post macrosetae on urotergites I-III. In addition, this Greek form shows important differences in the number and distribution of urotergal macrosetae: urotergite III with 1+0 la, 1+1 post; urotergite IV with 1+1 la, 4+5 post; urotegites VI-VII with 3+3 la, 5+5 post. Others features are: protruding frontal process with abundant tubercular setae; subequal claws with large lateral crests, posterior claw with a backward overhang; smooth subapical tarsal setae; stylus setae with abundant but separated barbs.

Habitat and distribution
Subterranean species only found in Bus del Globo Cave, in Trentino, Italian Alps. The aff. form from a cave in Greece should be accepted with caution, as it could be a new taxon. Bareth & Condé, 2001 Plusiocampa gueorguievi Bareth & Condé, 2001: 24, fig. 9.

Habitat and distribution
Subterranean species found in a cave in Carinthia (Austria) and another one in the Kanin Mountains (Slovenia).

Etymology
This species is named in honour of Luc Hoffmann , an extraordinary man, a naturalist and philanthropist, who helped create many international conservation organisations and supported conservation research and actions in the Mediterranean and elsewhere.

Description
Body. Body length: 4.8 mm (juvenile), 4.7 and 5.4 mm (males from Spilio Doxa), 5.9 and 6.4 mm (females from Spilio Doxa), and 7.4 mm (male from Sfentoni Trypa). Epicuticle smooth under optical microscope, but reticulate at high magnification (Figs 68-69); body with thin, long clothing, smooth or with a few thin distal barbs on dorsal side and well barbed on ventral side, legs and urosternal appendages.

Phyletic affinities, habitat and distribution
The presence of medial posterior macrosetae on the mesonotum and metanotum relates P. (P.) hoffmanni sp. nov. to almost half of the species in the subgenus Plusiocampa, all living in the European region, including most of the Mediterranean islands. Among them, P (P) festae is probably the closest related species due to the distribution pattern of their notal macrosetae; in spite of the fact that both species live in Crete (Condé 1984a;Silvestri 1933a), they occupy different habitats, P. (P.) hoffmanni sp. nov. in deep subterranean habitats, P. (P.) festae in soil and subterranean superficial habitats. In addition to this ecological difference, there are several important features that allow them to be separated. Plusiocampa (P.) hoffmanni sp. nov. has troglomorphic traits, with longer appendages than P. (P.) festae and more antennomeres and cercal articles, with more complex and more numerous olfactory chemoreceptors within the cupuliform organ. In P. (P.) hoffmanni sp. nov., the claws are slightly unequal to subequal, but with large lateral crests and a backward prolongation of the posterior claws. Additionally, P. (P.) hoffmanni sp. nov. shows a protruding frontal process covered by tuberculated setae, 8+8 macrosetae on the first urosternite and 6+6 on the second to seventh urosternites. Some of these features also separate P. (P.) hoffmanni sp. nov. from P. (P.) rybaki, a poorly described troglomorphic species from the southern Balkan Peninsula (Condé 1956). Plusiocampa (P.) hoffmanni sp. nov. has been collected from the deep zone of 14 caves in the numerous karst areas of Crete (Fig. 204). Ionescu, 1951 Plusiocampa humicola Ionescu, 1951: 528, figs 1-6.

Differential diagnosis against the type form
This record is based on seven specimens found in Ledenjača Cave, Bosnia and Herzegovina (see Table  S2 in Supplementary Material). Due to their clear differences from the type of P. (P.) isterina, described from Movile Cave, they have been identified as P. (P.) aff. isterina. Specimens from Ledenjača Cave have a higher number of antennomeres (25-28), six olfactory chemoreceptors in a relatively large cupuliform organ (occupying one third of a short antennomere) and a clearer protruding frontal process with remarkable tuberculate setae.

Remarks
Ten specimens from the Chorros and Farallón Caves in Riopar, Albacete, Spain (see Table S2 in Supplementary Material) were used for SEM to study some features that are difficult to observe under an optical microscope. Epicuticle slightly reticulate, with large polygonal pattern (Fig. 107) with a whorl of thin gouge sensilla, 34-36 µm long, with an external transversal striped surface (Figs 96-100). Cupuliform organ with spheroidal olfactory chemoreceptors in a complex spiral shape (Fig. 95). Head suboval with slightly protruding frontal process (Figs 101-102). Labial palp with short neuroglandular setae (Figs 103-106). Tarsus with two ventral barbed rows (Fig. 112). Claws with large lateral crest with dorsal striated surface and with ventral longitudinal grooves separated by a multihemispherical surface (Figs 108-111). Male with a large area of glandular g 1 setae and slightly thicker subcylindrical appendages (Figs 113-117). Stylar setae covered by a few thin, short barbs (Fig. 118).

Habitat and distribution
Subterranean species found in 31 caves in the external zone of the Baetic Mountain Range, around the carbonate areas of the Cazorla, Segura, Alcaraz and Castril Mountains and the peripheral karst areas of Filabres Mountain and the Yesos de Sorbas, southeastern Iberian Peninsula (Fig. 203). Silvestri, 1932 Plusiocampa lagoi Silvestri, 1932: 78, figs xiii-xiv.
Plusiocampa (Plusiocampa) aff. lagoi Silvestri, 1932 Differential diagnosis against the type form One female and two juveniles (Coll. AS) collected in a couple of Croatian caves (see Table S2 in Supplementary Material) show several differences from the type form in: the non-troglomorphic shape; antennae with 24 antennomeres and four simple olfactory chemoreceptors; the number of urotergal macrosetae, with 1+1 post macrosetae on urotergite III, 6+6 post macrosetae on urotergite VIII and 8+8 post macrosetae on abdominal segment IX; and a unique ventral tibial macroseta.

Habitat and distribution
Hypogean species found in edaphic habitats. The nominate form is known from a couple of localities in Marizza and Cremastò, Ródos, Greece. The aff. form was found in two caves in the Dinaric Mountains. Condé, 1948 Plusiocampa latens Condé, 1948d: 49, fig. 1.

Remarks
Among the studied material there is a male from Žira jama and another male from Crnulja ponor from Bosnia and Herzegovina (see Table S2 in Supplementary Material) which match the original description and allowed the completion of the previous diagnosis (Coll. AS).

Habitat and distribution
Hypogean species found in three caves (Baba pećina, Crnulja ponor and Žira jama) in Bosnia and Herzegovina for the type form and one cave for the aff. form (Vidovića špilja, Croatia); all localities in the Dinaric Mountains.

Remarks
The study of one male adult of 4.6 mm body length collected from the MSS habitat in Xànthi, Gérakas, Greece (see Table S2 in Supplementary Material) allows the addition of information on the urosternites of the male. It has a narrow area of 96 glandular g 1 setae, arranged in 2-3 rows; enlarged and subcylindrical appendages with a distal area of up to 60 glandular a 1 setae (Fig. 119).

Habitat and distribution
Subterranean species inhabiting seven caves around the north-eastern Pre-Baetic reliefs on the Iberian Peninsula. Furthermore, it slightly extends its distribution to three more caves in the south of the Iberian Mountain Range. Condé, 1957 Plusiocampa magdalenae Condé, 1957: 9, fig. 1.

Habitat and distribution
Soil-dwelling species found at six edaphic sites on the island of Corsica, one on Isola Zannone and two at inland localities in Calabria and Lazio, Italian Peninsula. (Denis, 1930) Figs 120-123

Remarks
The studied material from Pouade Cave (see Table S2 in Supplementary Material) has allowed a better observation of the first urosternite with its very large appendages in males (Fig. 120), as well as a large area of glandular a 2 setae. The first urosternite of females has subcylindrical appendages (Figs 121, 123) and the surface is completely smooth (Fig. 122).

Habitat and distribution
Subterranean subspecies inhabiting two caves on the French side of the Eastern Pyrenees.

Habitat and distribution
Subterranean subspecies found in Grotte du Saint-Trou in the Saint-Baume Massif, northeast of Évenos, Alps de Provence, southeastern France.
Plusiocampa (Plusiocampa) rhea Sendra sp. nov. urn:lsid:zoobank.org:act:79F00B32-CCCA-4195-BB1F-52D3B2225C20 Fig. 124; Table 9 Etymology This species is named in honour of Rhea, mother of the Greek god Zeus and daughter of Gaea, the Earth goddess. She gave birth and cared for her son Zeus in the Ideon Andron Cave located in Mount Psiloritis, the highest mountain in Crete, where this new species was found.

Description
Body. Body length 3.8-4.9 mm. Epicuticle smooth under optical microscope; body with thin, middlesized clothing, covered or not by a few thin barbs.
Head. Three intact antennae in holotype and paratypes, with 30, 32 and 33 antennomeres, slightly shorter than body length (Table 9). Small coniform sensillum of third antennomere located in ventral position between c and d macrosetae. Central antennomeres 1.5 × as long as wide, apical antennomere 1.6 × as long as wide. Cupuliform organ occupying ⅕ of total length of apical antennomere, with 8-9 complex olfactory chemoreceptors. Gouge sensilla 30-32 µm long in a single distal whorl of 12-16 sensilla on each medial and distal antennomere. Frontal process plain, with non-tubercular setae and macrosetae with barbs along half to two-thirds; macrosetae along line of insertion of antennomere and x setae with similar lengths (a / i / p / x with relative lengths of 36 / 42 / 35 / 52 in holotype). Suboval labial palps with latero-external sensillum larger than sensillum of third antennomere, with two guard setae, up to 12 setae on anterior border and up to 180 neuroglandular setae.
cerci. One incomplete cercus on 4 mm long paratype with six articles in addition to basal article, 3.8 mm long; their articles show whorls of long macrosetae covered by thin barbs along distal twothirds, combined with whorls of smooth, thin setae, shorter than macrosetae, in addition to one apical whorl of short setae with a few distal barbs.
GeniTal orGanS. Male urosternite I with up to 160 glandular g 1 setae arranged in up to five rows with slightly enlarged subcylindrical appendages, each bearing up to 19 glandular a 1 setae.

Remarks
The 17 specimens studied, from four caves in the Dinaric Mountains (Bosnia and Herzegovina) (see Table S2 in Supplementary Material), allowed us to clarify some characters: five complete antennae preserved show 28-29 antennomeres, elongated antennomeres with a distal whorl of 12-14 long gouge sensilla (30-32 µm) (Figs 131-132); cupuliform organ with seven or eight spheroidal olfactory chemoreceptors, each with a jagged fold surrounding a central coniform structure covered by a highly visible, multiperforated polygonal net surface (Figs 125-130). Protruding frontal process with tubercular setae. Surface of epicuticle reticulate (Fig. 133). Smooth tarsal subapical setae and calcars with long barbs from base, pretarsus claws with large lateral crests (Fig. 134). Furthermore, they show a wider range in the number of urotergal macrosetae than mentioned in the diagnosis above. Plusiocampa (Plusiocampa) aff. schweitzeri Condé, 1947 Differential diagnosis against the type form The five studied specimens from Karakaya Cave in Turkey (see Table S2 in Supplementary Material) share the same macrosetal distribution found in the specimens from Bosnia and Herzegovina, with the exception of 7+7 post macrosetae on urotergite VIII and 9+9 post macrosetae on abdominal segment IX. Furthermore, two other important features separate these two forms, i.e., the shape of the claws (subequal claws and posterior claw with no backward overhang in the form from Karakaya Cave) and features of the frontal process (simple frontal process without tubercular setae in specimens from Karakaya Cave). However, more material is needed to describe these specimens with different features from Karakaya Cave, Mihalliçik as a new species.

Plusiocampa (Plusiocmapa) solerii
The only specimen collected is a female, a troglomorphic form found in a cave on the island of Cyprus (Coll. AS). This specimen shows several taxonomical differences from the type form. Body length 5.6 mm (metathoracic leg 3.2 mm long); 8.7 mm long antenna with 49 antennomeres; elongated antennomeres with 16-18 long gouge sensilla, more than eight complex sensilla in cupuliform organ; 2 or 3 ventral tibial macrosetae; 1+1 lateral anterior and 1+1 posterior macrosetae on fourth urotergite and 2+2 anterior lateral macrosetae on seventh urotergite.

Habitat and distribution
The type form was found in soil habitat on the island of Ródos (Greece) and at Izmir on the west coast of the Anatolian Peninsula, but the aff. troglomorphic form was found on Cyprus.

Remarks
The study of five females and one juvenile collected in four caves (see Table S2 in Supplementary Material) has allowed the completion of the former description, although new specimens from the type locality are needed for a proper redescription of this species. Nevertheless, a complementary and differential description has been made using the studied material.

Habitat and distribution
Apparently, this species only lives in caves, but its non-troglomorphic shape reveals a more superficial habitat (MSS or soils). It has been found in six caves in the southern karst areas of the Western Carpathians, where it was described from the Domica-Baradla cave system in the Slovak and Aggtelek Karst, on the border between Slovakia and Hungary. Silvestri, 1933 Plusiocampa strouhali Silvestri, 1933c: 30, tables i-ii.

Plusiocampa (Plusiocampa) strouhali cavicola
On the basis of this weak taxonomic character, the population from Odelsteinhöhle in the Gesäuse National Park, Austria has been classified as P. (P.) strouhali cavicola.

Habitat and distribution
The locatity of this species is still not clear, as a label confusion may have occurred between two localities, one endogean habitat in France (Tarn-et-Garonne, La Capelle-Livran, Caylus) and a small cave in Sicily (Scaletta Zanclea, south of Messina).   ; Table 12 Etymology The specific name comes from the geographic area where this new species was found, the plateau called Trnovski gozd (Trnovo Forest).

Other material
See Table S2 in Supplementary Material.
Head. Only two complete antennae, in a juvenile with 40 antennomeres. Bacilliform sensillum of third antennomere in ventral position between macrosetae d and e. Central antennomeres 1.3 × as long as wide. Eighteen to twenty thin gouge sensilla (30-34 µm) in a single distal whorl on each medial and distal antennomere; 2-3 coniform sensilla in same whorl, but also present in last antennomere. Cupuliform organ on apical antennomere with about eight complex olfactory chemoreceptors. Nonprotruding frontal process, with non-tubercular setae.
cerci. Incomplete cerci, a maximum of 5 primary articles have been observed in several specimens. Each primary cercus bears from six to ten disorganized whorls of long, barbed macrosetae, one distal whorl of smooth, long setae and an apical whorl of short, thin setae.
GeniTal orGanS. Male with two to four rows of up to 200 glandular g 1 setae, subcylindrical appendages with a small distal area of up to ten glandular a 1 setae; female with subcylindrical appendages with up to 8 glandular a 1 setae (Figs 155-156).

Phyletic affinities, habitat and distribution
Several species of Plusiocampa s. str. share important taxonomical features with P. (P.) ternovensis sp. nov., such as the clearly unequal claws with large lateral crests, the posterior claw with a backward overhang and the absence of medial posterior macrosetae on mesonotum and metanotum, but only P. (P.) balsani and P. (P.) affinis share a similar distribution pattern of notal and urotergal macrosetae. Nonetheless, the secondary sexual features of P. (P.) balsani, with the male having subtrapezoidal appendages and glandular a 2 setae, unambiguously isolate it from P. (P.) ternovensis sp. nov. Morphologically and geographically speaking, its closest related species is P. (P.) affinis, but some clear differences separate them. The very unequal claws (1.7-1.8), presence of only one ventral tibial macroseta and the 2+2 lateral macrosetae on the urotergites are features of the new species that are not present in P. (P.) affinis, which has unequal claws (1.3), two ventral tibial macrosetae and 1+1 lateral macrosetae on the urotergites. Plusiocampa (P.) ternovensis sp. nov. has been sampled in three caves at the edge of a karst plateau north of the town of Ajdovščina, in Slovenia. This karst area is in the northern part of the Dinaric Mountains, a transitional zone between the Mediterranean, Alpine, Dinaric and Central European biogeographic regions. In two of the caves, the species lives together with P. (Stygiocampa) nivea, although they segregate differently within the cave. Plusiocampa (P.) ternovensis sp. nov. lives at a wider range of depths, while P. (S.) nivea occupies a deeper zone of the cave, at a depth of 500 m in the Velika ledena jama v Paradani and Bela Griža 1 caves. The temperatures in these two deep caves increase with depth, from permanently under 0ºC (Velika ledena jama v Paradani, with permanent ice in the upper parts) to more than 4ºC in parts deeper than 500 m. In Ledenica pri Dolu, an ice cave with temperatures below 2ºC, we found only P. (P.) ternovensis sp. nov., while in the Bošnarjev brezen Cave (5.9ºC to 7.0ºC) we found only P. (S.) nivea. This suggests that P. (P.) ternovensis sp. nov. may be considered better coldadapted than P. (S.) nivea. Troglomorphic species. Antennae with 37-41 antennomeres. Very slight protruded frontal process with slightly differentiated smooth macrosetae. Pronotum with 1+1 ma, 4+4 la, 2+2 lp macrosetae; mesonotum with 1+1 ma, 3+3 la, 2+2 lp, 1+1 mp macrosetae; metanotum with 1+1 ma, 1+1 la, 2+2 lp, 1+1 mp macrosetae; long, barbed notal macrosetae; body with a small number of thin clothing setae with thin distal barbs. Two or three ventral tibial macrosetae; slightly unequal claws (1.08-1.12) with large lateral crests, posterior claw with backward overhang. Urotergites I-III with 1+1 post macrosetae; urotergite IV with 1+1 la, 3+3 post macrosetae; urotergites V-VII with 1+1 la, 5+5 post macrosetae; urotergite VIII with 6+6 (6+5) post macrosetae; abdominal segment IX with 8+8 post macrosetae; urosternite I with 7+7, urosternites II-VII with 5+5, urosternite VIII with 2+2 macrosetae. Stylar setae with a few thin barbs. Male with an area of glandular g 1 setae, subcylindrical appendages with glandular a 1 setae; appendages of female slightly thinner than those of male.

Habitat and distribution
Subterranean species known only from the Vodni Pech Cave, Vidin town area, in the Balkan Mountains, Bulgaria.

Habitat and distribution
Subterranean species found in 13 caves in a karst region on the left bank of the Iskar River, Sofia District, Balkan Mountains, Bulgaria.

Remarks
The study of 26 specimens collected from three caves (see Table S2 in Supplementary Material) allowed us to add characters to the diagnosis (Coll. AS).

Remarks
The studied material (see Table S2 in Supplementary Material) allowed us to make additions to the diagnosis (Coll. AS).

Remarks
The new material studied (see Table S2 in Supplementary Material) allowed the addition of minor taxonomic details revealed by SEM microscopy. The epicuticle, apparently smooth in optical microscopy, shows a subtle reticulate surface (Figs 166, 168) covered by well-barbed clothing setae (Figs 167-168). The macrosetae are also well barbed, but the multi-barbed urosternal macrosetae (Figs 169-170 by barbs (Figs 177-178) and the eversible vesicles are large (Fig. 179). Males have large subcylindrical appendages with a large area of glandular a 1 setae (Figs 175-176, 180).

Habitat and distribution
Subterranean species, well distributed around the northwestern Dinaric Mountains, so far found in 75 caves (Fig. 207).

Remarks
The studied material (see Table S2 in Supplementary Material) allowed the addition of information to the diagnosis. The specimens from Njegoš pećina, Njeguši (Kotor, Montenegro) and Đatlo pećina, Lebršnik, Gacko (Bosnia and Herzegovina) revealed new diagnostic characters in SEM microscopy: antennomeres with a whorl of thin gouge sensilla, 40-47 µm long with an external transversal striped surface in a V pattern 184), claws with large lateral crest with ventral longitudinal grooves separated by reticulate surfaces (Figs 183,(185)(186). The first urosternite of the adult male has lateral expansions, bearing plenty of glandular g 1 setae , and abundantly long and completely barbed urosternal macrosetae (Figs 189,192), like the stylar setae (Fig. 190), and similar to but thinner than the cercal macrosetae (Fig. 191). Condé, 1947 Differential diagnosis against the type form  Antennae with 50 antennomeres; urosternite without lateral expansions, with a large area of glandular g 1 setae; enlarged subcylindrical appendages with a distal glandular a 1 seta.

Habitat and distribution
Subterranean species widespread in 21 caves of karst regions of the southeastern Dinaric Mountains. Plusiocampa (S.) aff. remyi occurs in Vranjača (cave), Croatia.

Habitat and distribution
The two species of the subgenus Venetocampa, which inhabit the subterranean habitat, are found in two caves of the Veneto Region, northern Italian Peninsula (Fig. 211).

Description
Body. Body length 3.0 mm (holotype) and 2.8 mm (paratype). Epicuticle smooth under optical microscope; body with sparse middle-sized clothing setae, distal two-thirds with thin barbs.
Head. Two intact antennae in holotype, slightly longer than body length (3.5/3.6 mm), with 32/33 antennomeres, in paratype slightly shorter than body length (2.76/2.75 mm), with 32/32 antennomeres. Small, subcylindrical sensillum of third antennomere in ventral position between c and d macrosetae; central antennomeres 1.7 × as long as wide, apical antennomere 2.0 × as long as wide; cupuliform organ occupies ⅙ of its length, with 7 or 8 spheroidal olfactory chemoreceptors, each with at least two folds, in cupuliform organ; gouge sensilla starting on ventral side of third antennomere, with an apical row of eight gouge sensilla; fourth antennomere with 12 ventral gouge sensilla and 1 dorsal gouge sensillum; fifth antennomere with 12 ventral and 2 dorsal gouge sensilla; sixth antennomere with 13 ventral and 4 dorsal gouge sensilla; seventh antennomere with 15 ventral and 6 dorsal gouge sensilla; eighth antennomere with 14 ventral and 7 dorsal gouge sensilla; ninth antennomere with 12 ventral and 8 dorsal gouge sensilla; after tenth antennomere a complete apical whorl of gouge sensilla on each antennomere, with about 20 on medial antennomeres and 15 on distal ones. Frontal process with nontubercular macrosetae or setae; macrosetae along line of insertion of antennomere and x setae similar in length, with long, thin distal barbs, on distal two-thirds (a / i / p / x with relative lengths of 33 / 30 / 26 / 39 in holotype). Small suboval labial palps with a long subcylindrical sensillum, two guard setae, four normal setae and up to 72 neuroglandular setae.
Secondary Sex cHaracTerS. Male urosternite I without glandular g 1 setae, subcylindrical short, enlarged appendages with up to 21 large glandular a 1 setae. Adult female unknown.

Habitat and distribution
Subterranean species found in Biga de le Agnelezze Cave, Piani Eterni, Belluno, Italian Alps.

Habitat and distribution
Subterranean species found in three caves in the karst areas of Lebanon (Fig. 210).

Tachycampoid phyletic lineage
Other genera related to Plusiocampinae, the tachycampoid phyletic lineage Bareth & Condé (1981) originally proposed a unique and different tachycampoid phylogenetic lineage ("lignée Tachycampoïde") for a number of previously described genera: Tachycampa Silvestri, 1936 with one species from a cave in the western Rif Mountains (Silvestri 1936); Paratachycampa Wygodzinsky, 1944 with three species, one from a cave in Nuevo León (Mexico) and two from several caves in the eastern Iberian Peninsula (Wygodzinsky 1944;Bareth & Condé 1981); Juxtlacampa Wygodzinsky, 1944 with two species, one from a cave in Guerrero (Mexico) and another from a cave in Alta Verapaz (Guatemala) (Wygodzinsky 1944); and Jeannelicampa Condé, 1955 with one species from caves in Tell Atlas (Algeria) . Much later, Condé (1982) proposed a new genus within this phyletic lineage, Oncinocampa Condé, 1982, for a subterranean species from the north of the Iberian Peninsula and another one from Sardinia (Condé 1981b(Condé , 1982. A few years later, the diversity of Oncinocampa was increased with four more species, two from the same karst region in the Cantabric Mountain Range on the northern Iberian Peninsula (Sendra & Condé 1988, Bareth 1989 and two from caves in the Americas, one near São Paulo, Brazil (Condé 1997) and another in Veracruz, Mexico (Sendra et al., 2016). The number of species in Tachycampa has also been expanded with three new cave-dwelling species from Mexico (Sendra et al. 2016) (Fig. 209).
Taxonomic key to Euro-Mediterranean tachycampoid genera and species

Habitat and distribution
Subterranean species located in two caves: Bou Iacor and Misserghin Ravine in Oran, Tell Atlas, Algeria (Fig. 210).

Habitat and distribution
The six current species of this genus have been found in caves, although two are non-troglomorphic. They have an amphi-Atlantic distribution, with one species in Mexico, one in Brazil, three in the center of the Cantabrian Mountain Range on the Iberian Peninsula and one in Sardinia (Fig. 210). Sendra & Condé, 1988 Oncinocampa asonensis Sendra & Condé, 1988: 1019, figs 1-4, table 1.
Oncinocampa aff. falcifer Condé, 1982 Differential diagnosis against the type form Two specimens (Coll. AS), in poor condition and difficult to observe under the microscope, were collected in two adjacent caves, Sima de Landubia and Sistema de la Cubada Grande (Burgos) in the southeast of the Cantabrian Mountain Range. Mesonotum and metanotum with lp macrosetae, in addition to some variation in urotergal macrosetae. Nevertheless, new specimens should be collected before establishing a new species.

Habitat and distribution
Subterranean species known only from Sima del Trave, collected at a depth of 550 meters, Picos de Europa, Central Cantabrian Mountain Range, northern Iberian Peninsula.

Habitat and distribution
Non-troglomorphic species found in one cave and within soil at two adjacent localities in the east of Sardinia.

Paratachycampa hispanica
Diagnosis (Bareth & Condé 1981;Sendra 1988 Male without glandular g 1 setae; overdeveloped appendages with a large area of glandular a 2 setae and an apical area of glandular a 1 setae; subcylindrical female appendages with glandular a 1 and a 2 setae.

Remarks
The studied material (see Table S2 in Supplementary Material) allowed us to add taxonomic details revealed by SEM microscopy. Gouge sensilla abundant, as long as 28 µm, with thick transversal stripes with alternating rows of pores between them   . Lateral processes of pretarsus with S-shape, its ventral side covered with long, hooked barbs .

Habitat and distribution
The four species of this genus are found in subterranean habitats, in the deep areas of caves. It has an amphi-Atlantic distribution, with three species in Mesoamerica and another one in the Rif Mountains, northwestern Africa (Fig. 210). Silvestri, 1936 Tachycampa lepineyi Silvestri, 1936:

Remarks
The study of many specimens collected from five new caves (Coll. AS) (see Table S2 in Supplementary Material) allowed the addition of information to the diagnosis and the inclusion of other minor taxonomic characters: ventral sensillum in third antennomere; labial palps with thick sensilla, two guard sensilla, nine simple setae and about 80 neuroglandular setae; metathoracic leg reaching end of abdomen; calcars with long barbs running up from base in two rows; smooth subapical tarsal setae; stylar setae covered with a few long barbs, apical setae with large basal tooth.

Habitat and distribution
Subterranean species found in nine caves in the karst areas near Taza in the Middle Atlas Mountains, Morocco.

Species diversity, phylogenetic groupings and distribution
The systematic groups are here maintained as those previously suggested for Campodeidae (Silvestri 1912;Condé 1955a;Paclt 1957;Bareth & Condé 1981, 1984Sendra et al. 2016Sendra et al. , 2017aSendra & Weber 2018). Using morphological characters, a phylogenetic grouping seems natural for the five subfamilies of Campodeidae (Paclt 1957) plus the tachycampoid phyletic lineage proposed by Bareth & Condé (1981). Nevertheless, not all genera and subgenera seem monophyletic within Plusiocampinae and the tachycampoids. This is the case for the Asian and African species of Plusiocampinae (Condé 1993b;Sendra et al. 2012aSendra et al. , 2017a. However, the European and Mediterranean genera of Plusiocampinae and tachycampoids belong to two well-differentiated phyletic lineages with a distinct biogeographical pattern. The five Euro-Mediterranean genera of Plusiocampinae (Cestocampa, Hystrichocampa, Patrizicampa, Plusiocampa and Vandelicampa) share remarkable morphological characters: 1) the ventral position of the sensillum on the third antennomere; 2) the pattern of macrosetal distribution on the pronotum, with two pairs of lateral posterior macrosetae; 3) the elbow-like claws with lateral crests; and 4) two pairs of macrosetae on the eighth urosternite. They also have some taxonomically less important similarities, such as a smooth cuticle as seen in an optical microscope (cuticle often appears reticulated in SEM) and the absence of pores on the dorsal sclerites. The Euro-Mediterranean Plusiocampinae represent the vast majority of the entire subfamily, with 78 species out of the total 91 species around the world. Plusiocampa is the most diverse genus of Plusiocampinae, with 71 species and 10 subspecies from the Euro-Mediterranean region (Table 13, Fig. 211; see also Table S1 in Supplementary Material). The remaining genera are far less diversified: Cestocampa includes four species, while Hystrichocampa, Patrizicampa and Vandelicampa are monotypic (Fig. 210). This biodiversity estimate does not consider the Asian species of Plusiocampa and Cestocampa, proposed to be placed in new genera by Sendra et al. (2012aSendra et al. ( , 2017a. The European region appears to be the center of origin for Plusiocampinae, but new evidence of undescribed taxa from East Asia has emerged (Sendra, unpubl. data), suggesting Asia as the most likely center of origin. Nonetheless, more sampling efforts and studies in Central and East Asia are required to reach a clearer view of the origin and possible colonization scenario for this subfamily, highly diversified in subterranean ecosystems.
The evolutionary relationships among taxa are not clear within the Euro-Mediterranean Plusiocampinae. Cestocampa, Patrizicampa and Vandelicampa are split from Plusiocampa by a single character: the laminar processes of the pretarsus are covered by pubescence instead of being smooth and setiform, as in species of Plusiocampa. Hystrichocampa is separated by the unique pubescent, thick setiform lateral processes of the pretarsus. The subgenera of Plusiocampa are not well supported. Dydimocampa and Venetocampa might be paraphyletic and Plusiocampa s. str. might contain two different monophyletic groups (Sendra 2003;. Furthermore, in the case of Dydimocampa, P. (D.) evallonychia, P. (D.) euxina and a probable new species found in a cave in southwestern Serbia (D. Antić leg.) seem very closely related. Species of Stygiocampa certainly form a monophyletic subgenus, sharing several common characters, such as the reduction of mesonotal and metanotal macrosetae, the absence of dorsal femoral macrosetae, and the presence of several extra urosternal macrosetae in four of these species. In addition, they are geographically restricted to subterranean ecosystems around the Dinaric and Balkan Mountains (Bareth & Condé 2001). The monotypic Pentachaetocampa, with its five dorsal femoral macrosetae and the unique presence of glandular g 1 setae in females, is only found in a cave in southwestern Germany (Sendra & Weber 2018). Finally, Plusiocampa s. str., including 60 species and 10 subspecies, is widespread across the entire European and Mediterranean region (Table 13, Fig. 211; see also Table S1 in Supplementary Material). The two suggested monophyletic groups within Plusiocampa are characterized by two formula patterns in the distribution of notal macrosetae: the presence or the absence of medial posterior macrosetae or submacrosetae on the mesonotum and metanotum. A peculiar distribution formula pattern is revealed using this taxonomical criterion. Part of Plusiocampa s. str., specifically 25 species and 6 subspecies that do not have medial posterior or intermediate thoracic macrosetae, occupy the ancient European plates, the current Dinaric and Catalonian regions. The other 35 species and 4 subspecies of Plusiocampa s. str., which have medial posterior thoracic macrosetae, occupy more recently emerged plates in the east and west of the emerged Mediterranean plates (Table  13, Fig. 212; see also Table S1 in Supplementary Material) .
The tachycampoid lineage is less diversified than Plusiocampinae. It has four genera and eight species in the Eastern Mediterranean region (Table 14, Fig. 209; see also Table S1 in Supplementary Material). Three of these genera have amphi-Atlantic distributions, with species in Mesoamerica (Oncinocampa, Paratachycampa and Tachycampa) and Brazil (Oncinocampa) (Bareth & Condé 1981;Sendra et al. 2016).

Habitats and troglomorphism
Campodeids were considered by Racovitzӑ (1907: 426-427, 443) as "le Cavernicole idéal", the ideal troglobite. All campodeids are eyeless with positive thigmotactism, they have a soft body with a tracheal respiratory system and a thin cuticle, traits associated with a cryptic, subsurface life-style. Many campodeids, mainly within Plusiocampinae and the tachycampoids, inhabit the deep subterranean occupying a wide variety of hypogean habitats from edaphic to shallow subterranean habitats (MSS) and occasionally caves (Table 14, Fig. 213). Several of these hypogean species are almost only reported from MSS habitats. This is the case for P. (P.) festae and P. (P.) apollo sp. nov., as has been shown by the sampling effort carried out mainly in Greece by P.M. Giachino and D. Vailati in MSS habitats, both in karst and non-karst areas. The marked preference of these two species for MSS habitats has also been observed in other diplurans and collembolans studied in colluvial and alluvial MSS (Bareth 1983;Ortuño et al. 2013;Baquero et al. 2017;Sendra et al. 2017b). Nevertheless, the most frequent habitats for most of the Plusiocampinae and tachycampoids are the subterranean spaces in the vadose zone of the bedrock. A total of 73 species, subspecies or affinis forms of Plusiocampinae and eight species of tachycampoids inhabiting the Euro-Mediterranean region are cave-dwelling species -named in the text as subterranean species -found mostly in caves, with clear troglomorphic features (Tables 13-14, Fig. 213; see also Table S1 in Supplementary Material). They have larger bodies, up to 9 mm; the antennae are up to 2 × and the cerci up to 3 × as long as the body length. Furthermore, the antennae have more than 30 antennomeres, although there are a few exceptions in which a smaller number of antennomeres could be an indication of a regenerated antenna. Some species of Plusiocampinae, such as P. (P.) gadorensis and P. (P.) hoffmanni sp. nov. (Table 6) have 50 antennomeres and there are up to 54 in P. (P.) chiosensis sp. nov. and P. (S.) bureschi (Bareth & Condé 2001;Sendra 2001). In the tachycampoid O. asonensis, the antennae have up to 64 antennomeres (Sendra & Condé 1988). The antennomeres of these highly troglomorphic species are usually elongated, the middle antennomeres being 2 × or 3 × as long as wide.
Another remarkable troglomorphic trait is the length of the cerci (Tables 1, 4 -5, 8, 11), with clear differences between the non-troglomorphic species such as P. (P.) spelaea, showing cerci shorter than the body length (0.4-0.5 × as long) (Table 10), the slightly troglomorphic species such as P. (P.) strouhali cavicola and P. (P.) hoelzeli (Tables 5, 11), with cerci somewhat longer than the body, and the most troglomorphic species such as P. (D.) evallonychia and P. (P.) hoffmanni sp. nov. (Tables 1, 8), with cerci almost twice as long as the body. The longest cerci of all Plusiocampinae have been recorded in P. (P.) chiosensis sp. nov., with cerci 2.52 × as long as the body length (Table 4). A recent study of cerci elongation in campodeids suggests that the elongation of these appendages is an adaptation to improve sensitivity in subterranean environments, with two different growth patterns: the cerci of Campodeinae and Lepidocampinae have a positive allometric growth, whereas it is isometric in Plusiocampinae (Sendra et al. 2017a). This difference between subfamilies might be regarded as an adaptation to the different habitats they colonize. While the majority of species of Campodeinae and Lepidocampinae are non-troglobites, many of them being edaphic-endogean species thriving in the small spaces of the soil, most species of Plusiocampinae are troglobites inhabiting the deep subterranean ecosystems.  Bareth & Condé, 1981 subterranean Eastern Iberian Peninsula P. penyoensis Bareth & Condé, 1981 subterranean Calderona Massif, Eastern Iberian Peninsula Tachycampa Silvestri, 1936 subterranean Mesoamerica and Middle Atlas (Morocco) T. lepineyi Silvestri, 1936 subterranean Middle Atlas (Morocco) Another remarkable progressive troglomorphic trait in campodeid species is the notable increase of complexity in shape, size and abundance of the sensorial equipment on the antennae. Although the troglomorphic species have a similarly invariable number of trichobothria as epigean species, they have longer flagella. The gouge sensilla (with an unknown function) were first described in two highly troglomorphic species of Paratachycampa (Bareth & Condé 1981) and later found in all campodeid species (Reboleira et al. 2010;Sendra et al. 2010). Furthermore, troglomorphic campodeids show some differences in gouge sensilla compared with non-troglomorphic campodeids; in the troglobites they are more abundant (up to 20) and are usually, but not always, longer and thinner than in nontroglomorphic taxa (Sendra et al. 2017c). The most remarkable changes in the sensory organs caused by a subterranean life-style are observed in the olfactory chemoreceptors of the cupulifom organ. Olfactory chemoreceptors are spheroid sensilla surrounded by tiny folds or 'collarettes'. The cuticular invagination and the sensilla have a perforated surface, and these pores are more numerous in troglomorphic than in non-troglomorphic species (Juberthie-Jupeau & Bareth 1980). Outstanding examples are found in many troglobites such as J. stygia, which has the highest known number of sensilla (28) in each cupuliform organ . The SEM observation of these chemoreceptors in a few species shows a great complexity of folds, with a multiperforated surface that adopts some spiral patterns in Plusiocampa 30,(53)(54)95,126,(128)(129)(130)138,140,(157)(158)(159)(160). Other troglomorphic Plusiocampinae have more complex chemoreceptor shapes, such as Turkmenocampa mirabilis, with sphaeriform and ramiform chemoreceptors , or the network of coralliform structures in an undescribed Plusiocampinae from southern Asia (Sendra, unpubl. data). Plusiocampinae and tachycampoids share convergent evolutionary traits associated with the selective pressures of subterranean ecosystems (see Culver 1982;Hüppop 2000;Christiansen 2012), where the absence of light and patchiness of nutrients might promote the lengthening of appendages (Culver 1982;Bellés 1987;Christiansen 2012;Sendra et al. 2017c).
The ecological role of Plusiocampinae and tachycampoids still has to be studied. Field and laboratory observations suggest that they might be secondary consumers in the food web. Plusiocampinae and tachycampoids feed on the remains of organic matter coming from the surface, microorganisms and fungi, but also on dead animals (Fig. 205). The observation of the digestive tube of troglomorphic species often reveals complete body parts of microarthropods, such as small acari or insect larvae (Sendra, pers. obs.). This has already been recorded for soil-dwelling campodeids, although very rarely (Gunn 1992), and might suggest an opportunistic predatory behavior.
Campodeids are often found in syntopy in edaphic habitats, which is less frequent in subterranean habitats. Up to four species of campodeids are known to live in the same cave (Bareth & Condé 1981), and co-occurrence of two species is not rare (Condé 1948a). Data on the spatial distribution of cave Diplura within cave systems are scarce and we report here the presence of Plusiocampa (S.) nivea and P. (P.) ternovensis sp. nov. in two caves where they seem to be spatially segregated, occupying different cave depths (see Table S2 in Supplementary Material). These observations reveal a complex mutual relationship of syntopically occurring species pairs, as well as habitat preferences of certain species within the subterranean ecosystem.

Paleobiogeography, dispersion and colonization of subterranean ecosystems
Plusiocampinae and tachycampoids share strong troglomorphic features due to their hypogean life-style in deep subterranean ecosystems. They represent two of the most diversified, disperse and abundant groups of dipluran troglobites in karst areas of the Euro-Mediterranean region. Their current distribution suggests an old colonization of this region under different paleogeographical scenarios of the fragmented Tethys Sea. Distributions might be explained mainly through tectonic plates and microplate drift theory, and the dispersal, vicariance and extinction processes that have taken place for hundreds of millions of years.
Following a chronological paleobiogeographical history, tachycampoids might be the oldest phyletic group of the Campodeidae. Their disjunct distribution across the Atlantic, encompassing limited distribution areas in karst regions in West Europe, Northwest Africa, Mesoamerica and East Brazil, supports the hypothesis of a Pangean origin during the Mesozoic. These facts also support the ancient colonization of subterranean ecosystems (Bareth & Condé 1981;Sendra et al. 2016).
Due to the absence of dated molecular phylogenies, a plausible scenario is suggested based on morphological characters. Plusiocampinae might have originated in the center of Eastern Laurasia, from where they dispersed throughout European regions, reaching a few African karst areas, perhaps since the Eocene-Oligocene, when the closing of the Turgai Strait allowed the European-Asian connection (Decourt et al. 2000). At least two dispersal waves might have occurred for the two doubtful monophyletic groups of Euro-Mediterranean Plusiocampinae during the Cenozoic. These groups are separated by the absence or presence of medial posterior macrosetae on the mesonotum and metanotum . Following these criteria, the ancestors of Plusiocampa s. str. without thoracic medial posterior macrosetae (  (Sendra 1988(Sendra , 2003. These are the genera Podocampa Silvestri, 1932 andLitocampa Silvestri, 1933 among Campodeinae, and the genera Oncinocampa and Paratachycampa among tachycampoids. This first dispersal wave might have been limited in Africa by the earlier presence of two tachycampoid genera, Tachycampa and Jeannelicampa, with an exception on the Kabylian microplate, which moved towards the African plate much later (Rosenbaum et al. 2002;Schettino & Turco 2006). The wave of Plusiocampa without medial posterior macrosetae included the monotypic Patrizicampa of Sardinia, the subgenus Stygiocampa of the Dinaric Mountains and the Balkan System, and perhaps the subgenus Venetocampa of the Italian Mountains. This first dispersal could have settled and still be living today in   the Dinaric Alps, the isolated carbonate platform in Apulia and the later-fragmented eastern microplates of the Iberian Peninsula. This fragmentation of the eastern microplates (Santanach et al. 1986) explains the vicariant distribution of the Plusiocampinae found in French Provence, Catalonia, Sardinia, Kabylia   (Sendra 2003;).
The second dispersal wave of the Plusiocampinae with thoracic medial posterior macrosetae (Table 13) could have happened much later, in the late Miocene, from Anatolia along the Miocenic Alps.
This connection was open during this epoch (Rögl & Steiniger 1984) and allowed their dispersal into the Apennine, Jura, Carpathian, Rhodopes, Crimean and Caucasus Mountains, and onto the Mediterranean islands, as has previously been suggested for Leptodirini beetles (Giachino et al. 1998;Moldovan & Rajka 2007), so well represented in European subterranean ecosystems (Moldovan 2008). It is possible that these Plusiocampinae newcomers had reached the new lands emerged from the Tethys Sea on the Balkan Peninsula and the Aegean islands, Italian Peninsula, Rhône Valley, and Western Mediterranean, including the islands and the Pre-Baetic Mountains in the south of the Iberian Peninsula. The connected lands during the Messinian period might have allowed a much wider dispersion of Plusiocampa s. str., subgenera of Plusiocampa and genera of Plusiocampinae with mp thoracic macrosetae. This could have been the case for species of Plusiocampa s. str., but also for Cestocampa balcanica, C. iberica, P. (Dydimocampa) alhamae, P. (P.) inopinata and the monotypic Hystrichocampa and Vandelicampa ( Fig. 212) (Sendra 1988(Sendra , 2003. The present distribution areas of subterranean and edaphic Plusiocampinae and tachycampoids are probably not simply marked by ancient paleogeographic events, but might also have been affected during Pleistocene climatic changes. This could explain the total absence of Plusiocampinae and tachycampoids north of latitude 50º N, which roughly follows the southern frontier of the Last Glacial Maximum from Belgium to Crimea. The same may have occurred for all other troglomorphic diplurans, with the remarkable exception of Haplocampa wagnelli Sendra, 2019. This fact was pointed out early by Racovitzӑ (1907) and confirmed in recent cave biogeography studies (e.g., Culver et al. 2006). The absence of subterranean fauna would then be related to the lack of organic material, not reaching the caves and underground networks because of glaciation (Sendra & Reboleira 2014;Jiménez-Valverde et al. 2017). All northern species of Plusiocampinae distributed near the limits of the Last Glacial Maximum are non-troglomorphic members of Plusiocampa, which have short antennae with doliiform antennomeres and four simple cupuliform sensilla, as well as a small body with short legs and cerci. This is the case for P. (P.) humicola, P. (P.) spelaea and P. (P.) corcyraea (Sendra & Weber 2018). In this scenario of continuous climatic changes, Plusiocampinae and tachycampoid species that settled in northern European regions could have been wiped out several times during glacial periods. After these harsh climatic events, campodeids would not have been able to colonize or recolonize the subterranean habitats of northern Europe (Figs 209,213).
During the Mesozoic and Cenozoic, the Plusiocampinae and tachycampoid groups of the Euro-Mediterranean regions probably suffered countless extinctions. These phyletic lineages could have undergone speciation and diversification by vicariance after the split of land masses. Over time, subterranean colonization would have occured when an empty niche was available (Sendra & Reboleira 2014). As pointed out by Bellés (1991), survival (subterranean spaces as immediate refuges), opportunism (empty subterranean niches to colonize) or convenience (to escape from the competitive pressures of surface habitats) could be the main forces driving the colonization of deep meso-and macro-spaces underground.
Molecular phylogenetic studies are expected to shed new light on the systematics of Plusiocampinae and tachycampoids and may help us to understand their flourishing success in subterranean habitats, contributing to complete a better picture of the ancient colonization of the Euro-Mediterranean region.