中国双珠足甲螨属一新种(蜱螨亚纲:甲螨亚目:珠甲螨科)

A NEW SPECIES OF THE GENUS DYOBELBA FROM CHINA(ACARI: ORIBATIDA: DAMAEIDAE)

本文记述中国双珠足甲螨属一新种——箸双珠足甲螨Dyobelba biclavata sp.nov.

Norton(1978) proposed the genus Dyobelba with Oribata carolinensis Banks as type species. Up to now this genus is only known in America. This paper deals with a new species from Mt. Changbai, China.Dyobelba biclavata sp. nov. (figs. 1—10)Mean ventral length of three specimens 632.7μm (599—666); mean notogastral width 412.9μm(399.6—432.9). Body colour is light brown, even yellowship compared with mostly damaeid mites, notogastral setae black. Integum nt microtuberculate, granular cerotegument covering all body. Except distal part of tarsi, cylindrical cerotegument covering all legs. Prodorsum Postbothridial enantiophysis Ba usually rounded or triangular; Bp and dorsosejugal enantiophysis (D) and propodolateral apophysis (P) absent, Sensillus (ss) smooth, tapering but not flagellate.Notogaster Spinae adnatae (sa) curved antero-mediad. Setae c_2, la and lm shorter, with few barbs on all setae, The distance between c_1 short, paralied each other, directed forward. Mutual distance of setae c_2 4 times as long as that of c_1. Setae P series thiner p_1=p_2>p_3, curved lateroventrad.Venter Propodoventral enantiophyses Ta developed; Tp, and ventrosejugal enantiophyses (Ⅴ) absent. Parastigmatic enantiophyses (S) well developed, Sa triangular, with rounded tip; Sp rounded. Discidium (di) more sharply pointed than Sa. Epirneral setation 3-3-3-4(n=4). Anogenital region normal.Legs Leg Ⅳ very long, 1.7 times ventral body length. Setation (Ⅰ—Ⅳ, famulus included, number of solenidia in parentheses): trochanters 1-1-2-1; femora 7-6-5-5; genua 4(1)-4(1)-3(1)-3; tibiae 4(2)-5(1)-4(1)-3(1); tarsi 20(2)-17(2)-17-14. Tibiae Ⅰ, Ⅳ without d; tarsus Ⅰ with 3 eupathidium-p′, p″ and s. Tibiae Ⅱ, Ⅲ having setae d, coupled ψ.Holotype (C-9, in alcohol), June 25, 1980, from rotten wood. Paratypes 3(C-47, 49), Ⅵ—Ⅶ, 1979, from litter; 1(C-34), July 23, 1980, from rotten wood. All type specimens collected from mixed forest of conifer and broadleaf tree in Mt. Changbai (Jilin Provience). One paratype (C-47, slide) is in the collection of R. A. Norton others are deposited in the Institute of Zoology, Academia Sinica.Discussion There are two characters of this new species which are not known in other species of the genus Dyobelba. Usually epimeral setation 3-1-3-4, but it is 3-3-3-4 in this new species. Femora Ⅲ, Ⅳ of the species with 5 setae instead of 4 setae in the known species.The uniform presence of 3 pairs of setae on epimeres Ⅱ is an example of neotrichy, which is not common on the epimeres of damaeid mies. Such neotrichy was known in the genera Hungarobelba, Belba and Quatrobelba.