Centromerus milleri Deltshev, 1974. – Deltshev et al., 2011: 42. [misidentification]

Type material: NMNHS and MHNG; male holotype, 1 male paratype, 7 females paratypes; TURKEY, European part, Strandzha Mountains, Dupnisa Cave (41.84578, 27.55997; alt. 348 m), under stones and on cave walls; 25.07.2006; leg. P. Stoev & S. Lazarov. – 1 female paratype; same locality; 16.03.2008; leg. Boyan Petrov.

Diagnosis: The new species has somatic characters that correspond well to those of the genus Centromerus. It bears a close resemblance to C. milleri (Figs 4-6, 10-12, 15-16, 20-22), but can be easily distinguished by the absence of eyes and by smaller body size (Fig. 1). The male of C. petrovi sp. nov. can be distinguished from that of C. milleri also by the palp structure: the characteristic tooth on the distal part of the paracymbium is smaller and sharper than in C. milleri (Figs 2, 13), and the suprategular apophysis is forked (Figs 2-3, 13-14). The epigynes of both species are very similar, but in C. petrovi sp. nov. the basal part of the scape is narrower than in C. milleri, and the inner sides of the lateral lobes are parallel to each other (Figs 7, 17), whereas in C. milleri they are more converging distally, forming a triangle (Figs 10, 20). Moreover, the reduced stretcher in the distal part of the scape is shaped as a spherical button in C. petrovi sp. nov. (Figs 7, 17), while in C. milleri it is more elongated (Figs 10, 20).

Etymology: This species is dedicated to our late colleague and well-known Bulgarian biospeleologist and alpinist Boyan Petrov.

Description of male (holotype): Measurements: Total length 2.52; carapace length 1.08, width 0.90; chelicerae length 0.61, width 0.22; sternum length 0.72, width 0.65; abdomen length 1.51; leg I length 5.33 (1.44 + 0.32 + 1.55 + 1.30 + 0.72); leg II length 5.03 (1.33 + 0.32 + 1.44 + 1.26 + 0.68); leg III length 4.35 (1.26 + 0.32 + 1.15 + 1.08 + 0.54); leg IV length 5.61 (1.51 + 0.32 + 1.62 + 1.44 + 0.72). Coloration (Fig. 1): Carapace, sternum and legs pale yellow. Abdomen white to light grey. Male palpal cymbium and female epigyne light brown.

Eyes: Absent, only two small, hardly visible spots in place of anterior median eyes (Fig. 1).

Chelicerae: Anterior margin of groove with 4 well-developed teeth. Posterior margin with 4 very small teeth.

Legs: Femur I with 1 retrolateral spine in apical half and 1 dorsal spine in the middle. All tibiae with 2 dorsal spines. Palp (Figs 2-3, 13-14): Tibia with 4 stout retrolateral spines. Cymbium with a long postero-dorsal protuberance. Paracymbium large and prominent, with characteristic triangular tooth on its distal part. Suprategular apophysis wide at base and forked apically. Terminal apophysis lamellar. Embolus masive, bulging. Lamella characteristica long, ending in very thin whip-like process.

Description of female paratype (NMNHS): Measurements: Total length 2.81; carapace length 1.08, width 0.72; chelicerae length 0.54, width 0.22; sternum length 0.61, width 0.54; abdomen length 2.09; leg I length 5.14 (1.44 + 0.32 + 1.44 + 1.26 + 0.68); leg II length 4.83 (1.28 + 0.32 + 1.33 + 1.22 + 0.68); leg III length 4.57 (1.33 + 0.32 + 1.26 + 1.08 + 0.58); leg IV length 5.36 (1.44 + 0.32 + 1.55 + 1.37 + 0.68). Coloration and leg spination as in male.

Epigyne (Figs 7-9, 17-19): Oval in shape. Basal part of scape trapezoid, narrow at base, gradually widening towards tip. Distal part of scape expanded, bursae copulatrix well developed.

Distribution: Known only from the type locality in the European part of Turkey.

Remarks: This species was already recorded from Turkey under C. milleri by Deltshev et al. (2011). These authors discussed that the population from the Turkish Strandzha might belong to a new troglobitic species, closely related to C. milleri. This assumption was confirmed when re-examining the material. Therefore C. milleri should be excluded from the list of the spider species known from Turkey.

Centromerus valkanovi Deltshev, 1983: 53, pl. 1, figs 1-2, pl. 2 figs 1-2. – Demircan & Topçu, 2015: 178, fig. 2A-C. – Komnenov et al., 2016: 27, figs 57-58.

Centromerus turcicus Wunderlich, 1995: 656, figs 6-8. syn. nov.

Type material examined: Male holotype; NMNHS; Bulgaria, Varna, Asparuhovo; 8.09.1945; leg. A. Valkanov.

Other material examinded: Paratypes of Centromerus turcicus; NMSF; 5 males; TURKEY, Anatolia, Abant Mountain, near Bolu, alt. 1200 m; without date; leg. H. Korge.

Distribution: Known from several localities in Bulgaria, Greece and Turkey.

Remarks: This species was described from Bulgaria by Deltshev (1983), and recorded subsequently from the European part of Turkey (Demircan & Topçu, 2015) and from the Dadia National Park in northern Greece (Komnenov et al., 2016). Wunderlich (1995) described C. turcicus from near Bolu, Turkey. The pictures in Wunderlich (1995) show no differences from C. valkanovi and the author did not discuss the relationships of the two species, which prompted us to study the type material. When comparing the paratypes of C. turcicus syn. nov. (Figs 25-26) to the holotype of C. valkanovi (Figs 23-24, 27-28), we established with certainly that they are all conspecific and that C. turcicus should be synonymized with C. valkanovi. This extends the distribution range of the species and changes its zoogeographical status. It can no longer be considered a Balkan endemic, since it is already known from the Asia Minor. It is most likely a species with an Euxinic origin. The Euxinic fauna comprises mesophilic, forest-dwelling species with a zoogeographical centre along the southern and eastern (i.e. Anatolian) Black Sea shores (Gruev & Kouzmanov, 1994). The fact that all records are from forest habitats supports this assumption too. The species is probably even more widespread in the east, in the Pontic montane forests.