Smit Harry, Clavier Simon
Naturalis Biodiversity Center, P.O. Box 9517, 2300 RA Leiden, the Netherlands..
Zootaxa. 2019 Jan 9;4543(4):587-589. doi: 10.11646/zootaxa.4543.4.7.
The water mite taxon Scutobates Cook, 1966 was originally described from Liberia, and treated by Cook (1966) as a subgenus of Hygrobates Koch, 1837. One of the most striking characters of Scutobates is the absence of a dorsal furrow, a ring or partial ring of unsclerotised cuticle between the dorsal plate or closely fitting platelets and the ventral shield. In the Hygrobatidae, secondary sclerotization, where the integument of the idiosoma other than the coxae, gnathosoma, genital field and glandularia bases, hardens to form sometimes extensive and merging plates can be extensive. For example, in the genus Thoracohygrobates Lundblad, 1936 the secondary sclerotization extends from the venter laterally onto the dorsum leaving a strip of membranous integument, but there is no dorsal plate development and therefore no dorsal furrow (Cook 1974). In Scutobates, the dorsum is completely sclerotized and seamlessly merges with the venter. The absence of a dorsal furrow on a completely sclerotized watermite is very rare.
水螨分类单元斯库托螨属(Scutobates Cook,1966)最初是根据来自利比里亚的样本描述的,库克(Cook,1966)将其视为1837年命名的湿螨属(Hygrobates Koch)的一个亚属。斯库托螨属最显著的特征之一是没有背沟,即在背板或紧密贴合的小板与腹盾之间没有未硬化角质层的环或部分环。在湿螨科中,次生硬化现象较为广泛,即除了基节、颚体、生殖区和腺基部之外的躯体体表会硬化形成有时广泛且相连的板。例如,在1936年命名的胸湿螨属(Thoracohygrobates Lundblad)中,次生硬化从腹侧向背侧延伸,留下一条膜质体表带,但没有背板发育,因此也没有背沟(库克,1974)。在斯库托螨属中,背面完全硬化并与腹面无缝融合。在完全硬化的水螨中没有背沟的情况非常罕见。