Asiolasma ailaoshan ( Zhang, Zhao & Zhang, 2018 ), 2019

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 : 93-96

Asiolasma ailaoshan ( Zhang, Zhao & Zhang, 2018)

comb. nov.

Figs 1 , 47-59

Cladolasma ailaoshan Zhang, Zhao & Zhang, 2018: 12 (description of male and female).

Material examined: MHBU Opi-20160422; male holotype; CHINA, Yunnan Province, Zhenyuan County, Qianjiazai town, Daming Shan , Ailao Shan Natural Reserve , 24°16’12’’N, 101°15’46’’E, 2170 m; A. Nakamura leg.; 18.8.2011 . – MHBU Opi-20160423; female paratype; collected together with holotype .

Diagnosis: Body rather globular, prolonged anterior part of prosoma including eye mound and hood slightly elevated, distal part of hood slightly bent downward, tubercles of hood markedly fanned, massive apophyses on anterior margin of prosoma flanking hood laterally; marked sexual dimorphism in body size, female much larger than male.

Description

MALE

Body, dorsal side ( Fig. 53 ): Body rather flat but less flat than in A. schwendingeri sp. nov. when seen in la view ( Fig. 54 ); Tu oc at anterior margin of prosoma only slightly elevated and forming no marked bend, eyes not distinctly raised on tubercle, displaced beyond anterior margin of prosoma and integrated into proximal part of hood, central hood tubercle slightly bent downwards (la view); hood bearing one central unpaired and four lateral paired tubercles, proximal pair shortest (about half size of following one), next two pairs consecutively longer, last pair nearly as long as central unpaired tubercle; all hood tubercles interconnected by small anvil-shaped bridges close to their bases. Lateral to hood one long and massive apophysis on each side projecting from anterior margin of prosoma, slightly bent inwards and flanking hood, distinctly shorter than all other appendages in prosoma front area.

Posterior margin of opisthosoma with a row of six massive truncate tubercles slightly tapering towards rounded tip, longest in mid-part of row ( Fig. 53 ). Network of keel cells loose, most cells not closed and interconnected with neighbouring ones; three large central cells on prosoma, two additional small ones on disto-lateral margin of prosoma; on metapeltidium no cells but a transverse row of anvil-shaped tubercles all over its breadth; on opisthosoma irregular open cells of different sizes, the five largest ones opening towards posterior end of opisthosoma.

Ventral side: Coxae densely set with small setae-bearing tubercles on ventral surfaces and with dorso-distal rows of anvil-shaped tubercles; a row of anvil-shaped tubercles along anterior and posterior margins of coxae II-IV; coxae I and II with distal digitiform processes retrolaterally; coxa IV with similar process prolaterally. Genital operculum short, almost tongue-shaped, surface with irregular tubercles. Sternites with transverse rows of low keels, reduced along midline.

Chelicera ( Figs 55-56 ): Basal article in posterior part dorsally slightly invaginated (la view), in distal part a low apophysis set with a short seta; 2nd article with a massive rounded apophysis on upper side carrying a pointed hook directed downwards and running more or less parallel to front of 2nd article; setae of various sizes, longest on frontal surface, few setae laterally and prolaterally, no brush of setae, no obvious subcuticular glandular tissue. Pedipalp ( Fig. 58 ): Tr slender, slightly swollen on do side; two small tubercles on ve side, each one pointed and with a small seta; Fe long and slender, slightly bent downwards, slightly enlarged distally, set with few scattered setae, ventrally with scattered clavate hairs, few of those distally; Pt with basal stalk, slightly enlarged and bulge-like ventrally, with a loose field of short setae and only five clavate setae, no apparent glandular tissue below; Ti cylindrical and moderately slender, with indistinct basal stalk, not curved, dense cover of clavate hairs on all sides; Ta slenderer than Ti, distinctly stalked, slightly inflated on do side, densely covered with clavate setae all round, few longer normal setae at distal end.

Genital morphology ( Figs 47-52 ): Penis very long and slender, slightly more than two-thirds of body length, slightly depressed (do/ve view), basis broadened, deeply split into two parts, two muscles concentrated there, from basis slightly tapering towards apex, then parallelsided up to tip including glans (do/ve view); glans spindle-shaped and broadened (la view); stylus short and in straight continuation of glans, with a slight helical torsion. Armature consisting of uniformly long (proximal ones) or shorter (distal ones) spindle-shaped spicules, these symmetrical on do and ve side and arranged in three groups from distal to proximal: i) distal group: six spicules in somewhat irregular arrangement, ii) central group: four spicules mainly situated on do and la sides in annular arrangement, iii) proximal group: two spicules distinctly separated from central group on la edges of truncus, one each on la side.

FEMALE: Body much larger than in male; chelicera ( Fig. 57 ) without apophysis on 1st article, generally more slender but much larger than in male; pedipalp ( Fig. 59 ) much larger than in male, general appearance as in male, its Pt less bulged in ve view.

Measurements: Body length of male: 2.8 (n=1), of female 4.6 (n=1). Leg II length of male, of female in parentheses: Fe 2.68 (4.49), Pt 0.88 (1.21), Ti 2.37 (4.09), Mt 1.53 (1.94), Ta 1.33 (1.58) (data according to Zhang et al., 2018). Penis length in strongly curved state 1.05.

Relationships: Asiolasma ailaoshan appears closely related to A. juergengruberi sp. nov. The latter is much larger (3.0- 3.4 mm for male and female) than A. ailaoshan . Asiolasma ailaoshan is sexually dimorph, the female being much larger than the male (2.8 mm in male, 4.6 mm in female), the apophysis of the male 2nd cheliceral article is less high, more flat, its pointed thorn is directed more downwards and runs parallel to the front side of the article; the proximal pair of spicules of the glans penis is slightly closer to the mid-group spicules than in A. juergengruberi sp. nov.

Distribution ( Fig. 1 ): At present this species is only known from the Ailao Shan Natural Reserve in the Chinese province of Yunnan. The two specimens were collected from soil litter in a (sub)tropical rain forest at 2170 m altitude ( Zhang et al., 2018).

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 47-54. Asiolasma ailaoshan, male holotype. (47) Glans penis in lateral view. (48) Same in dorsal view. (49) Same in ventral view. (50) Truncus penis in lateral view. (51) Same in ventral view. (52) Same in dorsal view. (53) Body in dorsal view. (54) Same in lateral view. Figs 47-48 reproduced from Zhang et al. (2018). Scales: 0.05 mm (47-49); 0.26 mm (50-52); 0.70 mm (53-54).

Figs 55-59. Asiolasma ailaoshan, male(55-56, 58), female (57, 59). (55, 57) Right chelicera in prolateral view. (56) Same in retrolateral view. (58-59) Left pedipalp in prolateral view. Scale: 0.3 mm.