Three new species of Scyracepon Tattersall, 1905 (Isopoda: Bopyridae) from Pacific islands, with comments on the rarity of bopyrids parasitizing brachyurans Author An, Jianmei Author Zheng, Wanrui Author Liang, Jielong Author Paulay, Gustav text Zootaxa 2020 2020-09-09 4851 1 151 162 journal article 8532 10.11646/zootaxa.4851.1.6 0d005205-2241-4da5-9b00-be4d1a842067 1175-5326 4407327 2B3E81FE-D1DC-4087-B36D-80158A178638 Key to 29 genera of the subfamily Keponinae ( Hemicepon and Metathelges based on immature type specimens are excluded) 1 Abdominal parasites, female with almost smooth lateral plates and pleopods ............................... Rhopalione - Branchial parasites, female usually with digitate or tuberculate lateral plates and pleopods......................... ... 2 2 All pereomeres of female normally developed ............................................................... 3 - Pereomere 2 of female almost absent ............................................................ Onychocepon 3 One pair of lateral plates on every pleomere of female ......................................................... 4 - Two pairs of lateral plates on every pleomere of female ............................................. .. Cardiocepon 4 Female with some middorsal projections .................................................................... 5 - Female without middorsal projections .................................................................... 13 5 Endopodite of pleopod of female well-developed.......................................................... ... 6 - Endopodite of pleopod of female reduced or absent .......................................................... 10 6 All male pleomere segments distinct ....................................................................... 7 - Some male pleomere segments fused .............................................................. Scyracepon 7 Female with middorsal projection on pleomere 1 ..................................................... Megacepon - Female without middorsal projection on pleomeres ........................................................... 8 8 Antennae of female as long as body ................................................................... Ergyne - Antennae of female much shorter than body .......................................................... Allokepon 9 Pleopods of female without endopodites ............................................................ Mesocepon - Pleopods of female with reduced endopodites ............................................................... 10 10 Middorsal projections only on last 2 pereomeres of female ..................................................... 12 - Middorsal projections on more than last 2 pereomeres of female ................................................ 11 11 Lateral plates and pleopods of female with digitate margins ........................................... Cancricepon - Lateral plates and pleopods of female with smooth margins........................................... .. Paracepon 12 Pereomere 6 of female with more than one projection .................................................. Tylokepon - Pereomere 6 of female with one projection ......................................................... Grapsicepon 13 Pleopods of female with well-developed endopodites ......................................................... 14 - Pleopods of female with reduced endopodites .............................................................. 22 14 Tergal projection of female with densely tuberculate surface ............................................ Lobocepon - Tergal projection of female with almost smooth surface ....................................................... 15 15 Lateral plates and pleopods of female with smooth margins ................................................... 16 - Lateral plates and pleopods of female with digitate margins................................................. ... 18 16 Male with lateral plates........................................................................ .. Procepon - Male without lateral plates .............................................................................. 17 17 Female with wide lamellar lateral plates, male with slender uropods.................................... .. Coxalione - Female with narrow striped lateral plates, male with stout uropods.................................... ... Hypocepon 18 Head of female with bilobate anterior margin ............................................................... 19 - Head of female with convex anterior margin ............................................................... 21 19 Lateral plates and pleopods of female covered with tubercles, margins sparsely digitate ....................... Anacepon - Lateral plates and pleopods of female smooth, margins densely digitate .......................................... 20 20 Female with endopodites of pleopods slightly shorter than exopodites, barbula with 2 pairs of projections ............ Kepon - Female with endopodites of pleopods much shorter than exopodites, barbula with 3 pairs of projections ....... Dactylocepon 21 Male without pleopods ......................................................................... Metacepon - Male with pleopods ........................................................................... Heterocepon 22 Female with 5 pairs of biramous pleopods plus uropods ................................................ Castrione - Female with 5 pairs of uniramous pleopods plus uropods ..................................................... 23 23 Lateral plates of female with largely smooth margins ......................................................... 24 - Lateral plates of female with digitate margins ............................................................... 25 24 Exopodites of pleopods of female slightly shorter than corresponding lateral plates .......................... .. Epicepon - Exopodites of pleopods of female much shorter than corresponding lateral plates ......................... .. Atypocepon 25 Male with all pleomeres fused ................................................................... Hypercepon - Male with some pleomeres separated ...................................................................... 26 26 Female with reduced frontal lamina ................................................................ Apocepon - Female with well-developed frontal lamina ................................................................ 27 27 Frontal lamina of female tuberculate ............................................................... Onkokepon - Frontal lamina of female smooth ......................................................................... 28 28 Male with long uropods.......................................................................... .. Leidya - Male with short uropods ...................................................................... Trapezicepon