Trisaria, Shear, 2020

Shear, William A., 2020, The millipede family Striariidae Bollman, 1893: I. Introduction to the family, synonymy of Vaferaria Causey with Amplaria Chamberlin, the new subfamily Trisariinae, the new genus Trisaria, and three new species (Diplopoda, Chordeumatida, Striarioidea), Zootaxa 4758 (2), pp. 275-295: 283-284

publication ID

publication LSID


persistent identifier

treatment provided by


scientific name


new genus

Trisaria   , new genus

Type species: Trisaria rex Shear   , new species

Etymology: The name of the genus is an anagram (rearrangement of letters) of Striaria   . It should be treated as feminine in gender.

Diagnosis: Unlike species of Striaria   and Amplaria   , Trisaria   males lack labral spines, are usually smaller (5–10 mm long), and have a crest 4 (c4) on each side of the rings posterior to the fifth suppressed, much lower than c3 and c5. The gonopods are strikingly different and significantly more complex than those of striariines, and the ninth legpair is strongly reduced, with sternum, coxae and telopodites fused or partially so. For additional characters separating the two subfamilies, see the table above.

Description: Small striariid millipedes ( Fig. 42 View FIGURE 42 ; 5–10 View FIGURES 5–8 View FIGURES 9–14 mm long). Cranium of head with pebbled sculpture, males lack spine distolaterally on labrum. Two to four poorly formed, pigmented ocelli on each side of head. Mandibular stipes of males with low posteriorventral carina, with small carinal teeth. Collum ( Figs. 36, 37 View FIGURES 36–38 ) apparently with 10 crests, sixth crest on each side forming expanded lateral margin of collum. Male collum ( Fig. 37 View FIGURES 36–38 ) longer, broader than in female ( Fig. 36 View FIGURES 36–38 ). Second ring with broadly expanded pleural margin ( Fig. 36 View FIGURES 36–38 ). Succeeding rings with 10 crests, but posterior to ring 5, fourth crest on each side progressively suppressed, difficult to see on posteriormost rings—metazonites with strong ventrolateral marginal carinae possibly homologous to sixth crests ( Figs. 42 View FIGURE 42 , 43 View FIGURES 43–47 ). Telson ( Fig. 16 View FIGURES 15–19 ) lacking crests, short, lobes distinctly divided. Spinnerets short, projecting anteriorly. Paraparocts (para, Fig. 16 View FIGURES 15–19 ) densely granular, with 5 smooth depressions and three marginal setae. Male first legpair (l1, Fig. 38 View FIGURES 36–38 , Fig. 17 View FIGURES 15–19 ) robust, larger than second legpair, with 6 podomeres (trochanter lacking), prefemora and femora ventrally with very long, straight, blunt-tipped, 4-angled setae ( Figs. 17 View FIGURES 15–19 ); postfemora, tibiae and tarsi with shorter somewhat flattened setae. Male second legpair coxae with vas deferens opening on the anterior side at the base of a short, heavily setose process ( Figs. 38 View FIGURES 36–38 , 39). Male legpair 3 ( Fig. 18 View FIGURES 15–19 ) with long, blunt extensions from the coxae, sides parallel, distally acuminate and smooth ( Figs. 19 View FIGURES 15–19 , 40 View FIGURES 40, 41 ), without setae on posterior surface, anterior surface with scattered short appressed setae, prefemora with ectal lobes that interlock with pleural margin of corresponding pleurotergite. Male legpairs 4–7 distinctively enlarged and with flattened podomeres; lobes of coxae of legpair 7 covering bases of gonopods (cx7, Fig. 41 View FIGURES 40, 41 ). All legs with coarsely pebbled surface, scattered, flattened, scale-like setae ( Fig. 25 View FIGURES 20–25 ), becoming more like ordinary setae distally on tarsi.

Gonopods complex. Sternum (st, Fig. 32 View FIGURES 32–35 ) broad, well-defined, not fused to coxae. Coxae small, displaced laterally, with or without setae (cx, Fig. 33 View FIGURES 32–35 ). Two angiocoxite processes present, positioned mesally and laterally, each with anterior (mac1, lac 1, Fig. 21 View FIGURES 20–25 ) and posterior branches (mac2, lac2, lac3, Fig. 21 View FIGURES 20–25 ). Median (lac2) branch of lateral angiocoxite with many thin cuticular processes arranged in comb-like array. Colpocoxite (cc, Fig. 27 View FIGURES 26–31 ) variable in form, poorly sclerotized, with scaly cuticle. Legpair 9 ( Figs. 23 View FIGURES 20–25 , 28 View FIGURES 26–31 ) substantially reduced, sternum, coxae and telopodite articles fused, telopodite interlocking with process from ring 7 ( Figs. 20 View FIGURES 20–25 , 41 View FIGURES 40, 41 ) Legpair 10 ( Fig. 24 View FIGURES 20–25 ) with coxal glands, coxae conspicuously enlarged.

Vulvae as in Fig. 47 View FIGURES 43–47 .

Distribution: See Map 1. Known at this time only from western Washington.

Notes: The gonopods are described in more detail in the species accounts below.