Cladolasma parvulum Suzuki, 1963

Martens, Jochen, 2019, An ancient radiation: Ortholasmatine harvestmen in Asia - a new genus, three new species and a revision of the known species (Arachnida, Opiliones, Nemastomatidae), Revue suisse de Zoologie 126 (1), pp. 79-110 : 82-83

Cladolasma parvulum Suzuki, 1963

Figs 1-15

Cladolasma parvula Suzuki, 1963: 41 (description of juveniles; types not examined). – Shear, 2010: 17 (revalidation of genus, discussion of phylogenetic placement). – Zhang & Zhang, 2013: 450 (comparison with a Chinese species). – Schönhofer, 2013: 24 (species listing).

Dendrolasma parvula ( Suzuki, 1963) . – Suzuki, 1974: 121 (transfer and redescription of species based on adults; synonymisation of Cladolasma with Dendrolasma ).

Dendrolasma parvulum ( Suzuki, 1963) . – Shear & Gruber, 1983: 60 (figures, discussion of phylogenetic placement).

Material examined: CJM 2759; 1 male, 1 female; JAPAN, Shikoku, Ehime Pref., Mt Saragamine , beech forest, 1160 m; 33°49’ N, 132°46’E; N. Tsurusaki; leg. 7.10.1983 .

Remark: The species was correctly described by Suzuki (1963, 1974) and by Shear & Gruber (1983) in many details, but for a comparison with the mainland Asian species an extended description and additional drawings and images created by photo stacking are added here.

Diagnosis: Characterized by male genital morphology (spicules of penis in two groups of similar sizes and arrangement and an additional distal chaplet of four spicules) and by tubercles on dorsal side of scutum

(arranged irregularly, no distinct lattice of keel cells, scanty anvil-shaped tubercles).

Description

MALE

Body, dorsal side ( Figs 2, 4-5 ): Compared to Asiolasma species rather flat, corona analis and sternites markedly extended and causing a slightly inflated and elevated opisthosoma (la view); Tu oc slightly elevated; hood extending from anterior margin of prosoma and including a rather short hood after a short ascent running parallel to prosoma, carrying one distal and five lateral apophyses, the distal one longest, the lateral ones consecutively shorter in direction to basis, interconnected by small anvil-shaped bridges close to the basis of individual apophyses; a pair of long and massive, slightly fusiform apophyses extending from anterior margin of prosoma to about two-thirds of hood length. Posterior margin of opisthosoma with a row of about 15-17 massive tubercles of various lengths, slightly inflated at the apex, longest ones in mid-part of row; all apophyses of hood and rear end of opisthosoma covered with a dense coat of pointed, posteriad-directed denticles.

Lattice cell network of anvil-shaped tubercles inconspicuous ( Figs 2, 4-5 ), formed by low rounded tubercles and only rarely by interconnected anvil-shaped tubercles, most cells not clearly defined, if present irregularly shaped, tubercles forming only dense or loose agglomerations; on metapeltidium only a transverse row of tubercles, no cells; tubercles slightly darker than surface of prosoma and opisthosoma.

Body, ventral side: Cx front and back side with a row of tubercles, longest on Cx I in front, in addition with dense cover of low rounded tubercles, Op gen with low tubercles, free tergites bent to ventral side, with rear row of low tubercles, most pronounced on corona analis.

Mostly long rounded tubercles on Cx: I 1 pro-la, 1 retro-la, II 1 retro-la especially large, III -, IV 1 pro-la. Tubercles on Tr: I retro-la, II -, III 1 pro-la and retro-la each, IV 1 pro-la.

Chelicera ( Fig. 12 ): Basal article in posterior part dorsally slightly enlarged (la view), do side markedly constricted, saddle-shaped (la view), four strong pointed tubercles on distal part dorso-prolaterally, with few setae laterally and prolaterally, no brush of setae, no obvious glandular tissue. Second article with a strong stumpy apophysis on upper front pointing to ve side. Setae of various sizes, mainly on frontal surface.

Pedipalp ( Fig. 14 ): Tr slender, slightly swollen on do side; three pointed small tubercles on ve side, each with as strong seta; Fe strong and massive, relatively short, continuously widening toward apex, slightly bent downwards, loosely set with few scattered normal hairs except for a group of strong setae mediodistally; Pt slightly enlarged and strongly bulge-like ventrally in central part, glandular tissue recognizable below cuticle in enlarged ve part (outlined in Fig. 14 ); Ti cylindrical but slender, with indistinct basal stalk, not curved, dense cover of clavate setae concentrated in distal part; Ta slightly more slender than Ti, distinctly stalked, slightly inflated on do side, densely covered with clavate setae all round (mostly omitted in Fig. 14 ).

Legs: Rather short, all articles cylindrical; Fe widened distally, particular on legs I, III and IV; Tr of all legs set with rounded tubercles of various sizes, largest ones distally, all densely covered with massive microtrichia ( Figs 4-5 ); Fe, Pt and Ti of all legs densely covered with fine microtubercles similar to those on Tr, tubercles with fine microsetae interspersed; Mt and Ta only with fine setae.

Genital morphology ( Figs 6-11 ): Penis long and slender, strait, slightly depressed, markedly parallel-sided all over its length (do/ve and la view); basis slightly broadened, deeply split into two parts, containing nearly the entire portion of the two muscles, from there truncus slightly tapering towards glans (do/ve view) and glans towards stylus; glans spindle-shaped and broadened only in la view; stylus short, no helical torsion. Apex of penis with long spindle-like spicules of slightly different sizes and arranged into two groups: i) distally six spicules symmetrically arranged in a chaplet on la, do and ve side, ii) proximally two parallel rows of four larger spicules each, two of them on la side, others on ve side.

FEMALE ( Figs 3 , 13, 15 )

Similar to male; club-shaped tubercles on posterior margin of opisthosoma shorter than in male ( Fig. 3 ); chelicera ( Fig. 13 ) similar to those of male, including tubercles on basal article, no hook on 2nd article; pedipalp ( Fig. 15 ) as in male, but Fe less bent, less enlarged distally, Pt also enlarged ventrally but less so than in male, glandular tissue also recognizable below cuticle, few clavate setae ventrally. Opisthosoma more arched, giving the impression of a more globular body.

Measurements: Body length of male 3.0 (n=1), female 3.5 (n=1). Leg II length of male, female in parentheses: Fe 2.4 (2.2) Pt 0.7 (0.7) Ti 2.2 (-) Mt 1.5 (-) Ta 1.0 (-). Penis length 1.7.

Variation: Little variation was observed in male genital morphology. All drawings presented by Suzuki (1974), Shear & Gruber (1983) and in this paper, especially concerning spicules on the glans ( Figs 6-11 ), are very similar even in minor details. This may be due to the restricted genepool caused by minute distributional areas of this species. Branches of the hood in some specimens are asymmetrical and uneven on the left and the right side ( Figs 2-4 ), single branches are bent toward the mid-axis. The specimens examined have only few clavate setae on their pedipalpal articles but specimens illustrated in Shear & Gruber (1983: figs 202-203) have many on Fe, Pt and Ti. The latter may be due to abrasion in alcohol-preserved specimens.

Distribution ( Fig. 1 ): This species is confined to Shikoku Island, southern Japan, where the distributional ranges of its populations seem to be rather small. Mt Ishizuchi is mentioned in the original description; N. Tsurusaki provided a series of specimens from Mt Saragamine for study (see photographs and drawings). According to information presented by Suzuki (1963, 1974), the species is confined to moist and cool montane forests, mainly beech ( Fagus crenata ), with a rich understorey of various grass species, roughly between 1200 m and 1500 m altitude.

Figures

Fig. 1. Distributional records of ortholasmatine species in East and Southeast Asia. (1) Asiolasma billsheari sp. nov., China, Gansu, Qinling range. (2) A. juergengruberi sp. nov., China, Yunnan, above Lugu Hu. (3) Same species as before, China, north of Lijiang. (4) A. ailaoshan, China, Yunnan, Ailao Shan. (5) A. damingshan, China, Guangxi, Daming Shan. (6) A. schwendingeri sp. nov., Vietnam, Mt Ba Vi. (7) A. angka, Thailand, Doi Inthanon. (8) Dendrolasma parvulum, Japan, Shikoku Island.

Figs 2-5. Cladolasma parvulum. (2) Body of male in dorsal view. (3) Body of female in dorsal view. (4) Prosoma of male in dorsal view. (5) Opisthosoma of male in dorsal view. Photographs by J. Schmidt.

Figs 6-15. Cladolasma parvulum, male (6-12, 14), female (13, 15). (6) Glans penis in lateral view. (7) Same in dorsal view. (8) Same in ventral view. (9) Truncus penis in lateral view. (10) Same in dorsal view. (11) Same in ventral view. (12) Right chelicera of male in prolateral view. (13) Same of female. (14) Right pedipalp of male in prolateral view. (15) Same of female. Scales: 0.25 mm (9-11); 0.1 mm (6-8); 0.3 mm (12-15).