Doratodesmidae

The Doratodesmidae

is a relatively small family currently comprising 13 largely monobasic genera ( Zhang & Wang 1993). The volvation pattern is much more advanced, and this is apparently related to the particularly enlarged paraterga 2. A narrow flange or ledge (= hyposchism, as accepted in Oniscomorpha , Fig. 1 View Figs 1–11 , H) near the rear margin of the broadest paratergum 2, beneath and behind a series of more or less tuberculiform lobules (= suture, = schism, Fig. 1 View Figs 1–11 , S), appears specially designed to accommodate paratergum 3. The latter, in turn, shows a similar but even narrower flange for the anterolateral part of paratergum 4 to hinge into. The same concerns paratergum 4 and its hyposchism, which is specially designed for the receipt of the anterolateral portion of paratergum 5. Then the pattern changes so that the anterolateral portion of each paratergum subsequent to the fifth is placed beneath the caudal margin of the previous paratergum ( Figs 12, 15 View Figs 12–21 ). In other words, there is no hyposchism on the paraterga of body segments 5–18(19), hence the overlap is switched to typical, starting from body segment 5. Conglobation is tight and the coil is definitely complete.

The telson is normal but is usually tuberculate, ‘polydesmoid’, and with a fully exposed and conspicuous epiproct. During complete volvation of the animal the telson is tightly oppressed to the dorsal side of body segment 4 (when the following metaterga are provided with larger mid-dorsal protuberances, Figs 15, 16 View Figs 12–21 ), or 5 or 6 (when all metaterga are devoid of stronger mid-dorsal processes, Fig. 12 View Figs 12–21 ).

This family is characterised, amongst other things, by the prominent and relatively complex paraterga. The latter are always more or less strongly lobulated to incised at the lateral margin ( Figs 12, 15 View Figs 12–21 ); the dorsum is more or less roughly tuberculate, and certain metaterga in some species have particularly prominent mid-dorsal tubercles or crests ( Figs 15, 16 View Figs 12–21 ). The ozopores are very small to missing; the gonopod aperture is transversely oval and large ( Fig. 13 View Figs 12–21 ); the gonopods ( Figs 13, 14 View Figs 12–21 ) vary from simple to relatively complex, the telopodite is invariably elongate, the prefemoral portion is small, the coxae are subtriangular and fully fused along the midline, and each has a normal cannula; antennomere 6 is longer and larger than antennomere 5; the body is usually relatively small, 6–15 mm long and the limbus is present and dentate-spatulate. Further structural details can be found in Hoffman (1977 1982 a 1982 b 1990) and Simonsen (1990). Certain observations of the volvation pattern are provided by Hoffman (1977). The family is endemic to south-east Asia (with Yunnan, China and southern Japan being the northernmost records), the Indo-Australian archipelago and New Guinea.

Following both Hoffman (1980 1982 b) and Simonsen (1990), based on the gonopod structure, the relationships of Doratodesmidae are deemed particularly close to the Indo-Australian family Haplodesmidae , a small group often displaying enlarged paraterga 2, but not capable of volvation.