Ancistrosyllis, McIntosh, 1878

Plathong, Sakanan, Plathong, Jintana & Dean, Harlan K., 2022, Two new species of Ancistrosyllis McIntosh, 1878 (Annelida: Pilargidae) from the Gulf of Thailand, Western Pacific, Zootaxa 5128 (2), pp. 195-210 : 209

Key to the species of Group II Ancistrosyllis

(modified after Plathong, Dean & Plathong 2021)

1. Eyespots present...................................................................................... 2

- Eyespots absent...................................................................................... 3

2. First notopodial hooks from chaetiger 3; ventral cirri from chaetiger 3............................................................................. A. hartmanae Pettibone, 1966 ; Chesapeake Bay-Gulf of Mexico, Western Atlantic

- First notopodial hooks from chaetiger 5, ventral cirri from chaetiger 1......... A. cingulata Korschelt, 1893 ; Adriatic Sea

3. First notopodial hooks from chaetiger 3.................................................................... 4

- First notopodial hooks from other chaetigers................................................................ 7

4. Neurochaetae, single type, long non-limbate capillary chaetae................................................. 5

- Neurochaetae of 2 or more 2 types ........................................................................ 6

5. Ventral cirri from chaetiger 1; neurochaetae bifid tip; body papillae brown.............................................................................................. A. eidimtaiteae sp. nov.; Gulf of Thailand, Western Pacific

- Ventral cirri from chaetiger 2; neurochaetae, bidentate tip; body whitish.......................................................................................... A. fioronii Fiege & Böggemann, 1999 ; North Sea, Atlantic Ocean

6. Ventral cirri from chaetiger 1; neurochaetae bifid tips......................................................................................... A. nakkaritae Plathong, Dean & Plathong, 2021 ; Gulf of Thailand, Western Pacific

- Ventral cirri from chaetiger 3; neurochaetae unidentate tips................................................................................... A. kornkanokae Plathong, Dean & Plathong, 2021 ; Gulf of Thailand, Western Pacific

7. Ventral cirri from chaetiger 1............................................................................ 8

- Ventral cirri from chaetiger 3, first notopodial hooks from chaetiger 6....................................................................................................... A. jonesi Pettibone, 1966 ; Maryland, Atlantic Ocean

8. First notopodial hooks from chaetiger 4–6.................................................................. 9

- First notopodial hooks from chaetiger 13................ A. breviceps Hartman, 1963 ; Southern California, Pacific Ocean

9. Two types of neurochaetae............................................................................ 10

- Three types of neurochaetae.................................. A. suksani sp. nov.; Gulf of Thailand, Western Pacific

10. First dorsal cirri length as those of chaetiger 2, first notopodial hooks from chaetiger 4–6.............................................................................. A. groenlandica McIntosh, 1878 ; off Greenland, Arctic Ocean

- First dorsal cirri slightly longer than following ones; notopodial hooks begin at chaetiger 6........................................................................... A. commensalis Gardiner, 1976 ; North Carolina, Atlantic Ocean