Pseudoleiobunum, Suzuki & Ohrui, 1972

Tan, Desmond Kai Teck, Tsurusaki, Nobuo, Fong, Jonathan J. & Zhang, Chao, 2025, Reinstatement of the genus Pseudoleiobunum Müller, 1914 with the inclusion of a new species from Hong Kong and reallocation of the Leiobunum maximum species complex (Arachnida: Opiliones: Eupnoi: Sclerosomatidae), Zootaxa 5646 (3), pp. 301-343 : 314-315

Pseudoleiobunum (superspecies maximum ) maximum distinctum Suzuki, 1973

Leiobunum maximum distinctum Suzuki, 1973: 260–263 , Figures 4–5 , 132–138 (♂ Holotype: Mt. Yuwan-dake , Is. Amami-Oshima, Japan); 1976: 196, Figures 6–8 , 95.

Materials examined. (Is. = Island) JAPAN, KAGOSHIMA PREF.: Is. Amami-Oshima, Amami City, Sumiyocho, Kawauchi , Kawauchi Dam , 22 May 1999, 1♀, H. Minato; Is. Amami-Oshima, Setouchi-cho, 2 juv., 22 February 2005; 1 juv., 27 February 2005; 2 juv., 28 February 2005, A. Tanikawa; Oshima-gun, Setouchi-cho, Is. Kakeroma, 2 juv., 26 February 2005, A. Tanikawa; Is. Uke-shima, 1 juv., 27 February 2005, A. Tanikawa; Kikaicho, Is. Kikai-jima, Hyakunodai [N28°19.0506', E129°59.0491'], 190 m, 2 juv., 4 March 2005, M. Yago — JAPAN, OKINAWA PREF.: Is. Okinawa, Nago City , Mt. Kazu-u-dake, 1 juv., 13 February 1982, M. Shimojana; Kunikamison , Hiji Campground , 12 March 1982, 2 juv. (subad.), H. Okada; Is. Iriomote, R. Aira-gawa, 1♀, 1 April 2009, K. Takenaka .

Diagnosis ( Fig. 2B ). General morphology similar to P. maximum maximum , except for having much stronger legs and chelicerae and pedipalps with more armaments ( Suzuki 1976). Scutal surface densely but regularly granulated. Ocularium short, generally canaliculate but dorsally armed with a row of small, regularly spaced denticules. Supracheliceral lamina pointed, sparsely scattered with small but distinct sharp granules. Pedipalpal tarsal claws with general reduced teeth that is more significant compared to other subspecies of P. maximum , in some individuals the “teeth” are reduced to small, blunt granulations ( Suzuki 1973). Legs unarmed except for scatterings of small sharp denticles. Penis glans long, similar to that of P. maximum formosum , with folded lateral alate wingings ( Suzuki 1973, Martens 1987).

Distribution. The Ryukyu Islands (Is. Kikai-jima, Is. Amami-oshima, Is. Okinawa, Is. Iriomote) ( Fig. 12).

Notes. This subspecies is univoltine and overwinters as juvenile. Adults appear from June to August.

Figures

FIGURE 2. Comparisons between Pseudoleiobunum specimens. A–C Comparison of female dorsal bodies between three Pseudoleiobunum species, highlighting features of the genus, yellow rectangle highlighting the small central, dorsal hump on the dorsal scutum; yellow circles highlighting the elevated lateral-posterior edges of the dorsal scute, resembling a pair of tubercles. D–E Comparison of general body size between male and female. F–G Comparison of male and female cheliceral size. A P. maximum distinctum, female. B P. japanense japonicus, female. C P. lutulentum sp. nov, LINGU-INV117, female. D Dorsal view of the female body, LINGU-INV117. E Dorsal view of the male body, LINGU-INV118. F Full lateral view of male chelicera, LINGU-INV72. G Full lateral view of female chelicera, LINGU-INV146. Scale bars: 1 mm.

FIGURE 4. A–B Pseudoleiobunum lutulentum sp. nov., close-ups of pedipalpal tibia and tarsus apophyses. A (Left) Close-up of male pedipalpal patella and tibia, LINGU-INV154. A (Right) Close-up of female pedipalpal patella and tibia, LINGU- INV146. Red rectangles for patella apophyses, blue rectangles for tibia apophyses. Scale bar: 2 mm. B Full lateral view of left pedipalp; C–D Pseudoleiobunum lutulentum sp. nov. C Full lateral view of left chelicera. D Close-up of left chelicerae distal structure. Scale bars: 0.5 mm.

FIGURE 5. Pseudoleiobunum lutulentum sp. nov., close-up comparisons of femora II under light microscope and scanning electron microscope of leg surface, revealing the granules that are present in the legs of P. lutulentum sp. nov. A Light microscopy of leg II femur, LINGU-INV72. B Light microscopy of leg II femur, LINGU-INV106. C Scanning electron microscopy of the surface of leg II femur, LINGU-INV115. D Close-up of the granules on leg surface, LINGU-INV116. Scale bars: 100 μm for C; 20 μm for D.

FIGURE 6. Pseudoleiobunum lutulentum sp. nov., different views of male, female genitals, labrum, supracheliceral lamina and a close-up of the female seminal receptacle. A Ventral view of male genital, LINGU-INV47. B Dorsal view of male genital, LINGU-INV46. C Lateral view of male genital, LINGU-INV154. D Dorsal view of labrum, LINGU-INV154.. E Lateral view of labrum, LINGU-INV154. F Ventral view of labrum, LINGU-INV154. G Dorsal view of the supracheliceral lamina, LINGU- INV154. H Seminal receptacle, LINGU-INV145. Scale bars: 200 μm for A & B; 500 μm for C; 0.2 mm for D, E & F; 0.5 mm for G; 20 μm for H.

FIGURE 7. Pseudoleiobunum lutulentum sp. nov. Male genital under electron microscopy. A Dorsal view, LINGU-INV46. B Ventral view, LINGU-INV47. Scale bars: 100 μm for A; 200 μm for B.

FIGURE 8. 28S alignment maximum-likelihood phylogram. Tree rooted using Odiellus pictus OP1063 as outgroup shown.