INTRODUCTION

The family Trogulidae has a paleo-Mediterranean distribution and occurs all over this region from northern Africa and the Iberian Peninsula eastwards to the Near East, i.e. to the Caucasus countries (Šilhavý, 1966; Staręga, 1966) and Turkey (Gruber, 1968; Schönhofer et al., 2013), and northwards to the Alps and central Europe (Martens, 1978). Eastwards the species' diversity fades out in the Iranian Alborz Mts (Snegovaya et al., 2021), Kyrgystan (Tchemeris, 2013) and Tajikistan (specimens in CJM) where only isolated species from widely separated localities are present. To date the family comprises five genera and 56 species (Schönhofer, 2013). Three genera include the majority of species, especially Trogulus Latreille, 1802 (32 species), Anelasmocephalus Simon, 1879 (13 spp.) and Calathocratus Simon, 1879 (9 spp.). For Greece ten trogulid species (Chatzaki, 2020) have been determined, but due to the puzzling homogeneity of external and partly genitalic characters, species delimitation is often difficult to establish, sometimes it is simply impossible. Modern molecular genetic analyses proved the diversity of species to be much larger than formerly believed. In recent years, ten species of Trogulus new to science were identified in various Mediterranean countries and were described; several more await disentanglement and formal description (Schönhofer & Martens, 2008, 2009; Schönhofer et al., 2013). On the other hand, the genera Platybessobius Roewer, 1940 and Trogulocratus Roewer, 1940 were synonymized with genus Calathocratus, again on the basis of a genetic analysis (Schönhofer & Martens, 2010). This taxonomic act was particularly striking as these three nominal genera were clearly separated by distinct tarsal formulas, i.e. the number of tarsal articles on the walking legs I-IV. Tarsal formulas are believed to clearly characterize and define the genus Trogulus and the closely related (and allopatric) species within various species groups in Anelasmocephalus. The newly circumscribed genus Calathocratus now comprises species with different tarsal formulas, and a close relationship among them is clearly shown by molecular data (Schönhofer & Martens, 2010). Also, in Calathocratus, the hidden diversity is enormous. Schönhofer & Martens (2010) identified nine more or less widely separated Calathocratus clades from Italy to Turkey and the Caucasus, of which at least the majority merits species rank. Most of them are still undescribed due to the difficulty to elucidate morphological distinctions, which are important for species identification beyond genetics.

Anarthrotarsus is an enigmatic trogulid genus from Greece. It was erected by Šilhavý (1967) based on a male specimen from Corfu, the holotype, and a female from eastern Crete. No further specimens were collected ever since, therefore a genital morphological comparison of specimens from these widely separated populations was not possible. The drawings of Šilhavý (1967) already indicated that the penis morphology of the type species, A. martensi Šilhavý, 1967, is quite peculiar and very distinct from any other trogulid species. Schönhofer & Martens (2010) were unable to incorporate Anarthrotarsus in an extensive phylogenetic study about trogulids based on molecular genetics due to the lack of fresh material. Recently, new material of both sexes of the Cretan population became available to us, and it is now evident that the holotype and paratype of A. martensi do not belong to the same species. Therefore, the population from Crete deserves a new status and name, which we give here.

MATERIAL AND METHODS

The examined material originated from the Opiliones collection of the Natural History Museum of Crete and was obtained during NHMC expeditions in eastern Crete in October to December of 1997 and January to March of 2008. The sampling method was pitfall trapping, as described in Salata et al. (2020).

Original line drawings were produced using a camera lucida attached to a Carl Zeiss research microscope. The photographs (Figs 1-2) were taken with a Canon 5D with a MP-E 65 mm f/2.8 1-5x Macrolens. Measurements were taken by means of a micrometer disc attached to a Leica M165C stereomicroscope. All measurements are given in mm.

The distribution map was created with the software QGIS 3.16.

TAXONOMIC PART

Figs 1-2.

Anarthrotarsus trichasi sp. nov. (1) Body in dorsal view. (2) Legs III and IV in prolateral view. Scales: 1.0 mm. Photographs by A. Trichas.

Fig. 3.

Anarthrotarsus trichasi sp. nov.; localities on the island of Crete: 1 - Pacheia Ammos; 2 - Siteia Bay; 3 - Moni Toplou. White line indicates eastern border of the Dikti Mountain Range.

Figs 4-15.

Anarthrotarsus trichasi sp. nov., male paratype CJM 8995. (4-6) Penis in ventral, dorsal and lateral view, respectively. (7-9) Glans penis in ventral (7), lateral (8) and dorsal view (9; arrow pointing to enlarged illustration of bifid seta). (10) Right pedipalp in pro-lateral view. (11) Right chelicera in retro-lateral view. (12-15) Tarsi with claw in pro-lateral view: leg I (12), leg II (13), leg III (14), leg IV (15). Scales: 0.3 mm (4-6), 0.05 mm (7-9), 0.1 mm (10), 0.2 mm (11-15).

Table 1.

Measurements of pedipalp and legs of male (paratype CJM 8995) and female (in parentheses, paratype CJM 8994) of A. trichasi sp. nov.

DISCUSSION

Single references to trogulids in Greece date back to Roewer (1940, 1950) but the species there have never been studied in any detail. Schönhofer (2013) mentions seven species, a relatively small number for a Mediterranean country, Chatzaki (2020) ten species. Species of Trogulus occur over large parts of the country including the Aegean Islands, all are presently attributed to one or two species names. A large amount of cryptic species is assumed to be present, but details are unavailable at present. The situation of the Cretan trogulid fauna is somewhat complicated though only few species are concerned. Roewer (1940) described Calathocratus intermedius (Roewer, 1940) and C. singularis (Roewer, 1940), all from the western part of the island. The collecting circumstances of these records are somewhat doubtful (see Helversen & Martens, 1972) and have never been clarified. A molecular genetic study identified two closely related but clearly separated populations of C. singularis within Crete and another one from the Peloponnese (Schönhofer & Martens, 2010); their taxonomic status is unclear. The latter authors also mention a Trogulus locality on Crete, Deliana, of unclear species affiliation (“T. aff. gypseus”).

Among all these uncertainties, there is the single female specimen of Anarthrotarsus martensi, published already in 1967 (Šilhavý, 1967), the only record for this species until recently. Now males are available for study, and male genital morphology of specimens from both populations turn out to be remarkably different, and their status as separate species is evident. The male type specimen (allegedly) of A. martensi from Corfu is considerably smaller (3.95 body length) than males of A. trichasi (4.1-4.4 body length) and has a subdistally notably enlarged truncus (Figs 16-19), as well as a short glans covered by a loose array of short and stout setae. In contrast, the also distally parallel-sided penis of A. trichasi sp. nov. and its longish glans with only scattered bifid setae differ markedly. The distinct differences between the Corfu and Crete population raise the question whether both populations can at all be associated to the same genus. This is at least doubtful. The molecular genetic analysis of Schönhofer & Martens (2010) did not include either population, and the question remains open. A close relationship of A. trichasi sp. nov. with populations of Calathocratus is possible because of a strong similarity in their genital morphology. But the latter genus, with a distribution from northern Africa to Italy, the Balkans and Turkey and further east, is heterogeneous in itself and requires a detailed molecular and morphological study. For the time being we associate both species in question to Anarthrotarsus and expect clarification of the situation from a comprehensive molecular genetic study. As for the zoogeographical point of view, A. trichasi is recorded from three distant localities in Lasithi Province. All of these records are from the easternmost part of the island, without the Dikti Mts intervening and all east of this mountain range, which indicates an important role of these mountains as a biogeographical barrier between the east and the west of the island. Moreover, since the areas surrounding the A. trichasi localities are also covered with dry open shrublands, the distribution of this species may be more extensive than it is reported here. However, although information is still limited, we consider A. trichasi sp. nov. to be a small-scale endemic species of the eastern-most part of Crete.

Figs 16-19.

Anarthrotarsus martensi, male holotype. (16-17) Penis in dorsal (16) and ventral view (17). (18-19) Glans in dorsal (18) and ventral view (19). Scales: 0.3 mm (16-17), 0.05 mm (18-19).