Callobius shimojanai, Xiang & Pan & Yu & Xiao & Sun & Cheng, 2022

Xiang, Ke, Pan, Jinbin, Yu, Jiaojiao, Xiao, Lehui, Sun, Shao-Kai & Cheng, Ran, 2022, Two New Species of the Spider Family Amaurobiidae from the Ryukyu Islands, Japan, Bulletin of the National Museum of Nature and Science. Series A, Zoology (Zoology) 48 (4), pp. 139-146 : 144-146

Callobius shimojanai sp. n.

[Japanese name: Motobu-gakejigumo]

( Figs. 1C–D , 2C–D , 3B , 7 , 8 ) http://zoobank.org/urn:lsid:zoobank.org:pub

Type material. Holotype ˁ, JAPAN: Mt. Katsuudake, Katsuyama, Nago-shi , Okinawajima Island , Okinawa Pref., 13 February 1982, M. Shimojana leg. (NSMT-Ar 22146) . Paratypes: 4 ˁ3 ˂, same data as the holotype (NSMT-Ar 22147); 1˂, Mt. Nagodake, Nago, Nago-shi , Okinawajima Island , Okinawa Pref., 10 February 2022, Y. Suzuki leg. (NSMT-Ar 22148)

Etymology. The specific name is dedicated to Dr. Matsuei Shimojana who collected the new species for the first time.

Diagnosis. Callobius shimojanai sp. n. can be distinguished from other congeners by the mutually crossing DP and MP in the tibia of male palp and the tip of the lateral lobes located close to each other in the epigyne. The new species clearly different from C. breviprocessus , which inhabit the same island, by the above characteristics ( Figs. 1 , 2 ). For differences from the other two species, C. yakushimensis and C. amamiensis in the Ryukyu Islands, refer to Okumura et al., 2020.

Description. Male (holotype). Total length 4.6, carapace 2.5 long, 1.8 wide; abdomen 2.1 long, 1.5 wide; sternum 1.2 long, 1.0 wide. Eye sizes and interdistances AME 0.06, ALE 0.11, PME 0.13, PLE 0.13; AME-AME 0.04, AME- ALE 0.06, PME-PME 0.09, PME-PLE 0.11, AME-PME 0.23, ALE-PLE 0.05. MOA; anterior width 0.16, posterior width 0.35, length 0.42. Leg measurements: I: 11.3 (2.9, 3.8, 2.8, 1.8); II: 7.1 (2.1, 2.5, 1.5, 1.0); III: 6.0 (1.9, 2.0, 1.2, 0.9); IV: 7.9 (2.2, 2.6, 2.0, 1.1).

Palp ( Figs. 1C–D , 8A–C ): three projections present in the lateral to dorsal portion of tibia; RTA thick and has a minute process in the tip, DP somewhat small and pointed in the tip, MP long, the two processes mentioned above cross each other. cymbial excavation clear; CO thin and semitransparent, median apophysis thick and claw-shaped, embolus short and conglutinates with the tegulum.

Chelicerae: promargin with 6 teeth, retromargin with 6 teeth.

Colouration: carapace yellowish brown with indistinct radial flecks, dorsum of abdomen grayish brown with five pairs of white markings, and venter with two pairs of white lines in both lateral sides, sternum grayish brown, chelicerae, maxillae and labium blackish brown, legs yellowish brown without ring flecks.

Female (one of paratypes). Total length 5.6, carapace 2.6 long, 1.8 wide; abdomen 3.0 long, 2.3 wide; sternum 1.2 long, 1.0 wide. Eye sizes; AME 0.05, ALE 0.13, PME 0.11, PLE 0.11. Distances between eyes; AME-AME 0.06, AME- ALE 0.08, PME-PME 0.10, PME-PLE 0.15, AME-PME 0.20, ALE-PLE 0.06. MOA; anterior width 0.16, posterior width 0.32, length 0.36. Leg measurements: I: 6.8 (1.9, 2.4, 1.4, 1.1); II: 5.4 (1.6, 1.9, 1.1, 0.8); III: 4.8 (1.4, 1.6, 1.1, 0.7); IV: 6.3 (1.8, 2.2, 1.5, 0.8).

Epigyne and internal genitalia ( Figs. 2C–D , 8D–E ): lateral lobes ligulate and close to each other at the tip, median lobe quite small and indistinct, ectal lobe and posterior lobe absent. SP anteroposteriorly elongated, slender toward the posterior margin and distant from each other, fertilization ducts small and indistinct.

Chelicerae: promargin with 5 teeth, retromargin with 6 teeth.

Colouration: almost same as that of the male holotype.

Distribution: Okinawajima Island ( Fig. 6 )

Figures

Fig. 1. Comparison of male palps of Callobius cavernarius sp. n. (A–B); C. shimojanai sp. n. (C–D); and C. breviprocessus (E–F). Male palp (left), dorsal view (A, C, E); same, ventral view (B, D, F). Scale bars=0.5mm.

Fig. 2. Comparison of female genital organs of Callobius cavernarius sp. n. (A–B); C. shimojanai sp. n. (C–D); and C. breviprocessus (E–F). Epigyne, ventral view (A, C, E); female internal genitalia (B, D, F). Scale bars=0.5mm.

Fig. 3. Comparison of body appearance of female specimens. Callobius cavernarius sp. n. (A); C. shimojanai sp. n. (B); and C. breviprocessus (C). Scale bars=10mm.

Fig. 7. Callobius shimojanai sp. n.; one specimen of female paratypes. Scale bar=2mm.

Fig. 8. Copulatory organs of Callobius shimojanai sp. n. holotype (A, B, C), paratypes (D, E). Male palp (left), ventral view (A); same, retrolateral view (B); same, dorsal view (C); epigyne, ventral view (D); female internal genitalia (E). Scale bars=0.5 mm.

Fig. 6. Distribution records of Callobius cavernarius sp. n. and C. shimojanai sp. n. including three closely related species living on the Ryukyu Islands.