Sabacon imamurai Suzuki, 1964

Tchemeris, Aleksey N. & Trilikauskas, Laimonas A., 2016, А Contribution To The Knowledge Of Sabacon Imamurai Suzuki, 1964 (Arachnida: Opiliones: Sabaconidae), Acta Biologica Universitatis Daugavpiliensis 16 (2), pp. 247-255 : 249-252

Sabacon imamurai Suzuki, 1964 (Fig. 1-13,

Fig.14)

Material: RUSSIA: 38 ♂, 74 ♀ ( ISEA), Khabarovsk Territory, Bureinskii State Nature Reserve , 6 August 2002, L.A. Trilikauskas ; 23 ♂, 22 ♀ ( MMUE), same territory, upper reaches of

Fig. 1–3. View of body Sabacon imamurai : 1 – male, dorsally; 2 – female, dorsally; 3 – female, laterally. Scale bar: 1 mm.

Bureya River, c. 1 km of the confluence of Levaya and Pravaya Bureya Rivers, 22–27.VIII.2002, L.A. Trilikauskas; 3140 individuals taken from the fist locality in 2002–2004 are deposited in the personal collection of L.A. Trilikauskas.

Distribution: Japan: Kyushu, Honshu, Hokkaido ( Suzuki, 1964, 1965, 1974; Suzuki & Tsurusaki, 1983; Tsurusaki & Minato, 2000); Russia, the Russian Far East: the Bureinskii State Nature Reserve in Khabarovsk Territory (Trilikauskas, 2009; present data) ( Fig.14.).

Description: Male: Measurements (n=38). Body: length 2.59–3.37; width 1.38–1.60. Carapace length: 0.78–0.85; width: 1.25–1.54. Ocularium width: 0.25–0.30. Chelicera: basal segment 0.65–0.73; distal segment 0.75–0.98; chela length

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0.45–0.53. Penis: length 1.33–2.44.

Length of palp segments: Tr 0.45–0.46, Fm 1.09–1.38, Pt 0.89–1.05, Tb 1.01–1.40, Ts 0.65– 0.68; total 4.09–4.97. Length of leg segments I: Fm 2.41–2.63, Pt 0.90–0.97, Tb 2.08–2.41, Mt 2.36–3.39, Ts 2.81–3.02; total 10.56–12.42. II: Fm 3.46–3.70, Pt 0.98–1.01, Tb 2.61–3.27, Mt 3.92–4.60, Ts 4.81–5.84; total 15.78–18.42. III: Fm 2.44–2.71, Pt 0.87–0.95, Tb 1.94–2.15, Mt 3.06–3.66, Ts 3.09–3.41; total 11.40–12.88. IV: Fm 3.27–3.81, Pt 0.96–1.12, Tb 2.47–2.75, Mt 4.05–5.12; Ts 5.57–6.36; total 16.32–19.16.

Compared to other Sabacon species, the body of S. imamurai is rather large and weakly chitinized (Fig. 1–4). Carapace and scutum are divided by a visible furrow, both almost smooth, with hardly noticeable (not risen) microsculpture.Abdominal scutum: scutum parvum towards laminatum.

Cephalotorax and abdominal tergites without sharp borders.Abdominal sternites distinct, each with a longitudinal row of hairs in its middle part. Supracheliceral lamellae smooth. Ocularium simple, with rare setae (Figs 1–4).

Chelicerae (Figs 5–6): their basal segments without a dorsal apophysis (in some species dorsal apophyses are well developed). Distal segment slightly ridged proximally, with 1–3 black frontal tubercles, rarely with few accessory tubercles. Chela digits with numerous flat microsetae.

Palps elongated, normally proportioned, not swollen (Figs 1, 4). Patellae armed with a ventromedial row of numerous black tubercles (Figs 7–8). Tarsal claws absent.

Legs as in all Sabacon are long and thin with rows or sparse hairs and setae. Claws of all legs are simple.

Penis: corpus slender and elongated, flattened dorso-ventrally, with a widened base, moderately swollen apically (Figs 9–11). Glans swollen with one prominent dorsal process at the distal margin, armed with numerous long spines on its ventral surface and a few fine long spines on its dorsal surface (Fig. 11–13).

Female: Measurements (n=74). Body: length Fig. 4-8. Male of Sabacon imamurai : 4 – body, laterally; 5 – chelicerae, frontal-laterally; 6 – distal segment of chelicerae, frontally; 7 – patella of palp, laterally; 8 – dentate area of patella palp, laterally. Fig. 5-8 electron-scanning microscope.

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4.22–4.56; width 2.22–2.41. Carapace length: 0.59–0.85; width: 1.75–1.79. Ocularium width: 0.33–0.34; Chelicera: basal segment 0.85; distal segment 1.00–1.10; chela length 0.45. Length of palp segments: Tr 0.37–0.55, Fm 1.46–1.50, Pt 1.18–2.21, Tb 1.65–2.05, Ts 0.72–0.74; total 5.38–7.05. Length of leg segments: I: Fm 2.57–2.63, Pt 0.96–0.98, Tb 2.38–2.62, Mt 2.94–3.12, Ts 2.83–2.91; total 11.68–12.26. II: Fm 3.64–3.57, Pt 0.95–1.15, Tb 3.05–3.29, Mt 4.36–5.08, Ts 4.85–5.32; total 17.42–18.41. III: Fm 2.55–2.62, Pt 0.90–0.98, Tb 2.14–2.28, Mt 3.29–3.41, Ts 3.32–3.55; total 12.20–12.84. IV: Fm 3.44–3.70, Pt 1.06–1.11, Tb 2.56–2.92, Mt 4.14–5.00, Ts 4.67–4.96; total 15.87–17.69.

Female general appearance is similar to that of the male (Fig. 2–3), but differs in the following characters: body usually larger, abdomen swollen and bluntly pointed posteriorly, scutum laminatum or scutum laminatum towards dissectum, all abdominal tergites free, each provide a small chitinized patch in the middle tergit.

Coloration. Male: Sclerotized parts of dorsum cephalothorax and abdomen ochre-brown to black-brown, except for white-ochre, softer, membranous structures. Ocularium black. Sternites and genital operculum lighter than tergites, ochre or ochre-grey. Limbs ochre-brown to dark brown. Penis brown to black. Female: usually lighter than the males, light ochre-grey to ochre brownish.

Variations: There is a considerable intraspecific variation in the body size and leg length (see above for the measurement ranges).