Three new species of shell-boring Dipolydora (Annelida: Spionidae: Polydorini) from the South China Sea and the Gulf of Thailand, Vietnam, with comments on the modified spines in posterior notopodia and sperm morphology in polydorins Author Radashevsky, Vasily I. text Zootaxa 2022 2022-07-06 5162 2 101 119 journal article 93673 10.11646/zootaxa.5162.2.1 1a1b824b-db11-4d16-90fa-b621801f0ce1 1175-5326 6809879 11BA9195-9A8E-4098-975B-E010627F9DFD Key to species of shell-boring Dipolydora from the South China Sea and the Gulf of Thailand 1 Posterior notopodia with only capillary chaetae. Pygidium trilobed, with one ventral lobe and two smaller dorsal lobes....................................................................................... D. vietnamita sp. nov. - Posterior notopodia with awl-like spines in addition to capillary chaetae. Pygidium cup-shaped, with dorsal gap or incision, or bilobed, with dorsal and ventral incisions.................................................................. 2 2 Caruncle to end of chaetiger 2. Chaetiger 5 falcate spines with central main fang, large lateral tooth and apical structure appearing as wide cowling or third tooth on convex side of main fang; numerous fine bristles present on basis of teeth. Branchiae from chaetiger 7, up to seven pairs................................................................... D. armata - Caruncle extending beyond chaetiger 2. Chaetiger 5 falcate spines without fine bristles on distal end. Branchiae from chaetigers 7−9, more than seven pairs............................................................................. 3 3 Caruncle to end of chaetiger 3. Occipital antenna absent. Chaetiger 5 falcate spines with thin collar on convex and lateral sides. Branchiae from chaetiger 7. Awl-like spines in posterior notopodia double-edged, with distal end slightly curved and basal end pointed, up to six in a tuft. Spermatids joined in tetrads....................................... D. echinata sp. nov. - Caruncle to middle of chaetiger 5. Short occipital antenna present. Chaetiger 5 falcate spines with spoon-like hollow on concave side and narrow transverse shelf on convex side. Branchiae from chaetiger 8 (rarely chaetiger 9). Awl-like spines in posterior notopodia with basal end truncate, usually three in a tuft. Spermatids joined in octads........... D. spinosa sp. nov.