Dicranolasma ridvansahini, Kurt & Kurt & Yağmur, 2025

Dicranolasma ridvansahini sp. nov.

( Figs. 1–5 View FIGURE 1 View FIGURE 2 View FIGURE 3 View FIGURE 4 View FIGURE 5 ; map 1; table 1–3)

Type Material: Holotype ( Arachnological Laboratory of Siran Vocational School , Gümüshane University , GümüŞhane, Türkiye , GUSAL): 1 ♂, TÜRKİYE, İzmir Province, KemalpaŞa District; Nif Mountain ( 38°22'47"N 27°22'13"E), asl 1126 m, 15.VII.2022 – 15.XI.2022, leg. E. A. Yağmur & S. AnlaŞ GoogleMaps . Paratypes. 2 ♂, same data as holotype. ( 1 ♂ in GUSAL, 1♂ in AlaŞehir Zoological Museum, Manisa of the Celal Bayar University, Turkey , AZMM) GoogleMaps .

Etymology: The specific epithet is in honor of Prof. Dr. Rıdvan ŞAHİN ( GümüŞhane University, GümüŞhane, Türkiye), who has made important contributions to the field of mathematics.

Diagnosis: The new species is similar to D. hoberlandti Šilhavý, 1956 and can be distinguished by the following morphological characteristics:- the basal segment of the chelicerae with wide and conical in shape, with a long dorso-apical apophysis (fig. 2a, b; 3c). In D. hoberlandti , the basal segment is hump-shaped and a small apophysis ( Šilhavý, 1956: tab. 1, fig. 2; Staręga, 1973: fig. 3).- the penis is basally oval-shape and narrow, then slightly widens and maintains nearly parallel sides up to the glans. The glans penis bears sparse setae (fig. 4). In D. hoberlandti , the penis basally widened and triangular in shape. Truncus penis progressively narrowed from the base to the center; then slightly widened towards the glans; the glans with dense setae ( Šilhavý, 1956: tab. 1, figs. 4–5; Martens, 1965: figs. 3–5; Staręga, 1973: figs. 5–6).

Dicranolasma ridvansahini sp. nov. is also similar to D. scabrum , but different in the following morphological features: D. ridvansahini sp. nov., the basal segment of the chelicerae is wide, conical in shape, and bears a long apophysis. In D. scabrum , the basal segment of the chelicerae with hump-shape shape and lacks the long apophysis ( Martens, 1978: fig. 238).

D. ridvansahini sp. nov., the truncus penis is basally ovoid and narrow, then slightly widened, with nearly parallel sides up to the glans. The glans penis is covered with sparse hairs. The stylus is distinctly elongated, curved in an S-shape and shaped like a bird’s beak. In contrast, in D. scabrum , the truncus penis is broader and flattened at the base, gradually narrowing toward the glans and slightly widening just below it. The glans penis is covered with dense hairs, and the stylus is also markedly elongated and slightly curved in an S-shape, but it is widened at the tip ( Martens, 1978: figs. 246–247).

Description: male ( holotype). Body ( Fig. 1a View FIGURE 1 ): The dorsal habitus is shown in figure1a. Body nearly rectangular, the posterior region with oval-shaped in dorsal view. Body length 4.4, width 2.1. Dorsal body with scattered spiny tubercles, longer and more prominent posteriorly.

Eyes and head cap: Head cap length 1.1; width 1.2; eye interdistance 0.8; eyes distance (outside to outside) 0.9. On the anterior side of the prosoma, there is an oval-shaped head cap that covers the chelicerae and pedipalps from above. Head cap branches with long papillae on inner and outer sides, longer median area. Eye mound absent, eyes located on the centre-lateral margin of the head cap.

MAP 1. Type locality of Dicranolasma ridvansahini sp. nov. (black triangle). The map was obtained from www.https://www. harita.gov.tr/ and modified for the purposes of this study.

Chelicerae ( Fig. 2a, b View FIGURE 2 ; 3c View FIGURE 3 ): Small, not enlarged. Basal segment length: 0.8, distal segment: 0.89. Basal segment with prominent conical apophysis rising from the middle/dorso-distally as a hill, covered with dense long setae. Basal segment ventrally with three spiny tubercles; laterally covered with many microtubercles. Distal segment with setae.

Pedipalps ( Fig. 2c, d View FIGURE 2 ; 3b View FIGURE 3 ): Length of pedipalp segments: 0.65+0.43+0.47+0.39; total length 1.94. Trochanter dorsally and ventrally with long setae. Femur narrow at base, progressively widening toward patella and covered with setae. Patella dorsally flat, ventrally rather enlarged, oval shaped and covered with long setae. Tibia with setae. Tarsus narrowed toward tip, wedge-shaped, and covered with setae.

Legs ( Fig. 1b, c View FIGURE 1 ; 3a View FIGURE 3 ): The femur to tibia segments of legs I, III, and IV are distinctly thickened, whereas leg pair II is slender. Femur-metatrsi covered with denticles. Tarsus only with bristle. Number of tarsalsegments: I: 6; II: 10; III: 7; IV: 7. Length of legs I: 1.4+0.52+0.88+1.17+0.76=4.73; II: 3.01+0.95+2.5+2.3+2.05=10.81; III:1.41+0.83+ 1.04+1.6+0.87=5.75; IV:1.85+0.9+1.53+2.4+0.91=7.39

Genital morphology ( Fig. 4 View FIGURE 4 ): Truncus of penis basally oval-shaped and narrow, then slightly widened, with parallel sides in the middle, then slightly narrowing towards the glans penis. Glans covered with spines. Stylus is markedly elongated and beak-shaped, reminiscent of a bird’s beak.

Female: Unknown.

Morphological remarks: A morphological comparison of the newly described species with closely related taxa is given in the diagnosis section. The genus Dicranolasma is divided into five species groups: - scabrum group: D. scabrum (Herbst, 1799) , D. opilionoides (Koch, 1867) , D. hoberlandti Šilhavý, 1956 , D. giljarovi Šilhavý, 1966 , D. kurdistanum Staręga, 1970 , D. thracium Staręga, 1976 , D. ressli Gruber, 1998 , D. ponticum Gruber, 1998 ., D. cretaeum Gruber, 1998 ; - mladeni group: D. mladeni Karaman, 1990; - cristatum group: D. cristatum Thorell, 1876 ; D. hirtum Loman, 1894 ; D. pauper Dahl, 1903 ; - soerensenii group: D. soerensenii Thorell, 1876 , D. verhoeffi Dahl, 1903 . - apuanum group: D. apuanum Marcellino, 1971 ( Gruber, 1998). Based on the apophysis on the basal segment of the chelicerae, the presence of setae on the trochanter of the pedipalp, the number and structure of the pseudosegments of the legs, and the structure of the penis, the new species belongs to the scabrum group of the genus Dicranolasma Sørensen, 1873 .

Molecular remarks: A 1096 bp fragment from the 28S rRNA gene sequenced.Average frequencies for Adenine (A), Thymine (T), Cytosine (C) and Guanine (G) were 19.1, 18.2, 28.4 and 34.4 % respectively. The average nucleotide frequencies were found to be elevated in C+G, and the C+G ratio was found to be greater than the A+T ratio, as presented in table 3.

p-distances ranged from 0.01% to 0.066% among the Dicranolasma species analysed in this study. The overall distance value was found to be 0.029%. The species with the highest genetic distance from the newly described Dicranolasma ridvansahini sp. nov. is D. mladeni (0,059), while the closest species is D. scabrum (0,010) ( Table 2).

As detailed in the section titled ‘Morphological remarks’, Dicranolasma ridvansahini sp. nov. exhibits distinct morphological characteristics that differentiates it from other members of the genus Dicranolasma . Moreover, molecular analyses of the data obtained from the 28S rRNA gene region of the species high Bayesian posterior probabilities (BPP) and p-distance values, thus positioning the new species in a distinct branch of the phylogenetic tree and designating it as a new taxon, divergent from the other species within the genus Dicranolasma .

The molecular and morphological data obtained as a result of this study are consistent with each other. A comprehensive analysis of both molecular and morphological data indicates that the newly described species Dicranolasma ridvansahini sp. nov. should be classified within the - scabrum group.

Habitat: Two MSS traps were placed in a rock deposit at the base of a cliff, where broken rocks accumulate. Specimens move through small gaps within the rock deposit and fall into the cups through the holes in the pipes. Dicranolasma ridvansahini sp. nov. was not captured in surface traps and was not observed during field surveys, suggesting that the species is specialized for a subterranean lifestyle. It was not collected from MSS traps placed in soil areas and was found exclusively in the rock-accumulated habitat. Moreover, it was not detected during winter sampling and was observed to be active only during the summer. The spider species Kut izmiricus Kunt, Elverici, Yağmur & Özkütük, 2019 was recently described from a nearby locality using the same method. This species was also found using the same MSS traps in the same locality as Dicranolasma ridvansahini sp. nov. ( Kunt et al., 2019).