Striariidea Cook, 1896

Shear, William A. & Marek, Paul E., 2019, Urochordeumatidae Silvestri, 1909, a millipede family endemic to Washington State, USA (Chordeumatida, Striariidea, Striarioidea), Zootaxa 4657 (2), pp. 352-360 : 353

Suborder Striariidea Cook, 1896

Shear (2000) placed Urochordeumatidae in the superfamily Caseyoidea , due to superficial similarities of the gonopods of Urochordeuma bumpusi to those of members of the genus Caseya Cook & Collins, 1895 . However, closer examination, particularly using scanning electron microscopy, supports placement in the superfamily Striarioidea instead. These features include the presence of a cerotegument (Latin cera = wax, tegumentum = covering; ct, Fig. 1 ), dorsal ornament of small two-pronged tubercles ( Fig. 4 ), a three-lobed epiproct ( Fig. 3 ) and anteriorly reflexed spinnerets. All of these characters are found in members of the family Striariidae ; while species of Caseyidae , the only family of Caseyoidea , lack a cerotegument, have an entirely smooth dorsum, an unlobed epiproct and posteriorly directed spinnerets. Therefore, we remove Urochordeumatidae from Caseyoidea and place it in Striarioidea . As detailed immediately below, U. bumpusi remains in a distinct family from Striariidae , Rhiscosomididae , Apterouridae and Buotidae—its relatives in Striarioidea .

Figures

FIGURE 1. Head and first four rings of Urochordeuma bumpusi Silvestri, 1909, male, ventral view. Abbreviations: Lab, labrum; ms, mandibular stipes; st1, sternum of first legpair; L1–L4, legpairs 1–4 respectively; fp1, femoral process of first leg; cx3, coxa of third leg; s4, sternal knob of legpair 4; ct, fragments of cerotegument pulled loose from cuticle. First legs shaded red, second legs yellow, third legs green and fourth legs blue.

FIGURES 2–4. Urochordeuma bumpusi Silvestri, 1909. 2: Rings 10–12 (10, 11, 12) of male. 3: Rings 28, 29 and telson (28, 29, t) of male. 4: Small cuticular nodules of metazonite, each with two acute, posteriorly pointing processes.