Allochthonius (Urochthonius) yoshizawai, Viana 1 & Ferreira 1, 2021

Viana 1, Ana Clara Moreira & Ferreira 1, Rodrigo Lopes, 2021, A new troglobitic species of Allochthonius (subgenus Urochthonius) (Pseudoscorpiones, Pseudotyrannochthoniidae) from Japan, Subterranean Biology 37, pp. 43-55 : 43

Allochthonius (Urochthonius) yoshizawai sp. nov. Figures 2 , 3 , 4

Type material.

Holotype male ( ICHUM-6165), in alcohol: Japan, Ehime Prefecture, Kumakogen, Hiura-do Cave (33°29'20.4"N, 132°55'48.0"E), on the cave wall (dark zone), 5 September 2017, R.L. Ferreira leg.

Etymology.

The specific name is given in honor of Dr. Kazunori Yoshizawa, not only due to the assistance provided during fieldwork in Japanese caves, but also to his great contribution to the knowledge of arthropods, especially Psocodea.

Diagnosis.

Differing from the other members of subgenus Allochthonius Urochthonius by the following combination of characters: carapace with 18 setae (6 on anterior margin, 2 on posterior margin); cheliceral palm with 6 setae, fixed cheliceral finger with large basal tooth, rallum with 11 blades (each with fine barbules, the basal-most blade shorter than the others); coxa I with a spray of 8 clavate coxal blades (subequal in length) on a mound, bisetose intercoxal tubercle present between coxae III and IV; on the fixed chelal finger, 7 (8 on the right chela) acute, narrow, large, widely-spaced teeth; on the movable chelal finger, 10 acute, small, widely-spaced teeth; chelal teeth varying in size.

Description of adult male (female unknown).

Troglomorphic habitus (Fig. 2A, B ). Body mostly translucent, with a vitreous aspect. Chelae, chelicerae, and tergites light pinkish orange; other parts of body white. Vestitural setae smooth, long and acuminate.

Carapace (Fig. 4B ): Nearly square in dorsal outline, 1.1 times longer than broad, slightly constricted posteriorly; anterior margin somewhat straight, but becoming indistinctly concave towards median region; without eyes or eyespots; two weak transverse furrows present, near anterior and posterior margins; chaetotaxy 6: 6: 2: 2: 2 (18).

Chelicerae (Fig. 3A, C ): Surface mostly scaly-reticulate. Hand with 6 setae (including 1 ventral seta); movable finger with 1 subdistal seta; galea absent; fixed finger with 4 apical teeth, including one large basal tooth (third one on right chelicera, fourth one on left), followed by small denticles (4-12); movable finger with 6-8 teeth of equal length, followed by 7 smaller teeth on left chelicera (a few denticles on right chelicera); rallum (Fig. 3C ) composed of 11 blades (7 in one row, 4 in another row) with fine barbules, the basal-most one distinctly shorter than the others (~1/3 length of other blades); serrula exterior with 18 blades, serrula interior of the left chelicera with 15 blades, 16 blades on the right.

Tergites: Undivided; chaetotaxy uniseriate, I-XI 2: 2: 4: 6: 6: 7: 9: 10: 8: 5: 2. Anal operculum without dorsal setae.

Coxae: Palpal: manducatory process with two setae, apical seta reduced; rest of palpal coxae with three setae. Pedal: coxae I each with a spray of 8 clavate blades (Fig. 4D ); chaetotaxy I 4, II 4-5, III 5, IV 5-6; intercoxal tubercle present between coxae III and IV, bearing two setae.

Genital operculum of male (Fig. 4A, C ): Anterior genital operculum with 6 anterior setae, and one posterior seta; genital opening with 8 setae on the right side, and 10 on the left.

Sternites: Chaetotaxy II-XI 13: 16: 17: 15: 15: 15: 12: 10:-:2. Anal operculum with one pair of ventral setae.

Palp (Fig. 3B, D ): Femur chaetotaxy: 6: 10: 4: 7: 2 (Fig. 3D ). Trichobothria ib and isb located on a small dorsal hump. Trichobothrial pattern (Fig. 3B ): trichobothrium sb distinctly nearer b than sb; it distad to est; trichobothria ib-isb-eb-esb-ist clustered at the base of fixed finger. On the left chela trichobothrium est is missing. Fingers distinctly curved, movable finger shorter than fixed finger. Fixed finger with 7 (8 on the right chela) acute, large, narrow, widely-spaced, irregular marginal teeth; on the left chela, the fourth distal tooth distinctly larger than the others, two small basal tubercles present; the right fixed finger marginal teeth larger compared with those of the left chela. Movable finger with 10 acute, small, widely-spaced, irregular teeth.

Leg IV (Fig. 3E ): Subterminal setae long and acuminate. Arolia shorter than claws, latter slender and smooth. Two tactile setae present, one on the metatarsus and another on the tarsus.

Measurements (length/breadth or, for legs, length/depth in mm, ratios in parentheses): Body length 1.97. Carapace 0.55/0.51 (1.1). Palps: trochanter 0.29/0.16 (1.8), femur 0.91/0.14 (6.5), patella 0.31/0.13 (2.5), hand with pedicel 0.54/0.26 (2.0), movable finger length 0.78, chela with pedicel 1.39 (5.3). Leg I: femur 0.53/0.08 (6.4), patella 0.32/0.07 (4.8), femur/patella (1.6), tibia 0.26/0.06 (4.7), tarsus 0.56/0.06 (10.2). Leg IV: femur+patella 0.77/0.17 (4.4), tibia 0.57/0.09 (6.1), metatarsus 0.28/0.07 (3.8), tarsus 0.64/0.06 (11.5), tarsus/metatarsus (2.3).

Figures

Figure 2. Allochthonius (U.) yoshizawai sp. nov., male holotype A habitus of male B live specimen in natural habitat. Scale bar: 2 mm (A).

Figure 3. Allochthonius (U.) yoshizawai sp. nov., male holotype A right chelicera, showing detail of surface texture, antiaxial (slightly ventral) view B right chela, showing trichobothrial pattern and marginal teeth, antiaxial view C right cheliceral rallum D left palp, dorsal view E left leg IV, retrolateral view. Scale bars: 0.25 mm (A); 0.5 mm (B, D, E); 0.125 mm (C).

Figure 4. Allochthonius (U.) yoshizawai sp. nov., male holotype. A Male genital operculum B holotype carapace, showing distribution of setae (most hairs missing) C male genital operculum D coxal blades on coxae I, ventral view. Scales: 0.25 mm (A); 0.5 mm (B); 0.1 mm (C, D).