Ammodesmidae, Cook, 1896

The Ammodesmidae View in CoL

is an oligotypic family with three genera and several species in tropical Africa ( Hoffman & Howell 1981; Van den Spiegel, in prep.). They are all so minute (2–5 mm long) that, when coiled and dusted with earth, these animals resemble a grain of sand ( Cook 1896). The conglobation pattern in the East African Elassystremma Hoffman & Howell, 1981 appears to be very much like in Doratodesmidae , but the overlap only becomes typical from paratergum 4 onwards ( Figs 22 View Figs 22–27 , 33 View Figs 32–36 ).

The telson is likewise normal, ‘polydesmoid’, and evident from above. The epiproct is flattened, conspicuous, sometimes tuberculate ( Fig. 33 View Figs 32–36 ), and during complete volvation of the animal it is tightly oppressed to the dorsal side of body segment 5 or 6.

The body teguments are usually rough; the metaterga are more or less strongly tuberculate, and the paraterga are rounded laterally, usually somewhat incised or sinuate anteriorly and caudally at their base ( Figs 22 View Figs 22–27 , 33 View Figs 32–36 ); the ozopores are small, poorly visible, and they open flush on the surface of the paraterga below the caudobasal incision; the ozopore formula seems to be somewhat abbreviated: 5, 7, 9, 12, 15, 17–18(19) ( Fig. 33 View Figs 32–36 ), and sometimes ozopores seem to be missing; the tergal limbus is evident and is dentate; antennomere 5 is longer and larger than antennomere 6 ( Fig. 22 View Figs 22–27 ); the legs are rather slender but short ( Fig. 23 View Figs 22–27 ); the gonopod aperture is transversely oval and large; the gonocoxae are extremely large and subtriangular, with normal cannulae which are strongly exposed; the gonocoxae are fused and hollow medially and often enlarged laterally so that the more or less slender telopodites are nearly fully concealed inside the gonocoel ( Figs 23 View Figs 22–27 , 34 View Figs 32–36 ) ( Hoffman & Howell 1981; Van den Spiegel, in prep.).

The only qualification to be noted here is that it still remains to be proven if both West African genera, Ammodesmus Cook, 1896 and Cenchrodesmus Cook, 1896 , are indeed confamilial with Elassystremma (cf. Hoffman & Howell 1981).