Sigambra Müller, 1858

Plathong, Jintana, Plathong, Sakanan, Klangnurak, Wanlada & Dean, Harlan K., 2024, Two new species of Sigambra (Annelida, Pilargidae) from the Andaman coast and the Gulf of Thailand, Zootaxa 5555 (1), pp. 1-23 : 20-21

Key to Sigambra Müller, 1858 from the Indo-Pacific region

(modified after Bhowmik et al. 2021)

1. Chaetiger 2 lacking ventral cirri; pharynx with 8 marginal papillae............................................... 2

– Chaetiger 2 lacking ventral cirri; pharynx with 12–14 marginal papillae.......................................... 4

2. Some neurochaetae with bifid tips; dorsal hooks from chaetigers 3–5; median and posterior notopodia with 2 capillaries per parapodia.................................. S. bidentata Britaev & Saphronova, 1981 (Sea of Japan, Pacific Ocean)

– Neurochaetae lacking bifid tips; dorsal hooks from chaetigers 3–7............................................... 3

3. Median antenna reaching to chaetiger 5; notopodia without capillaries, dorsal hooks from chaetigers 3–5..................................................................... S. papagayu Bamber in Muir & Bamber, 2008 ( Hong Kong)

– Median antenna 2 times longer than lateral antennae; notopodia with capillaries; dorsal hooks from chaetigers 3–8........................................................ S. qingdaoensis Licher & Westheide, 1997 ( China, Pacific Ocean)

4. First dorsal hooks from anterior chaetigers................................................................. 5

– First dorsal hooks from median chaetigers................................................................ 10

5. First dorsal hooks from chaetigers 3–10................................................................... 6

– First dorsal hooks from chaetigers 12–18; pharynx with 13 marginal papillae................................................................................... S. elegans Britaev & Saphronova, 1981 (Sea of Japan, Pacific Ocean)

6. Median antenna longer than lateral antennae; pharynx with 14 marginal papillae................................... 7

– Median antenna slightly longer than lateral antennae, pharynx with 13 marginal papillae; first dorsal hooks from chaetigers 7–10............................................... S. pettiboneae Hartmann-Schröder, 1979 (Western Australia)

7. First dorsal hooks from chaetiger 3–4; notopodia with capillaries............................................... 8

– First dorsal hooks from chaetiger 8....................................................................... 9

8. First dorsal hooks from chaetiger 3.................. S. phuketensis Licher & Westheide, 1997 (Andaman Sea, Thailand)

– First dorsal hooks at chaetiger 4.................................. S. hanaokai Kitamori, 1960 ( Japan, Pacific Ocean)

9. Notopodia with capillaries..................................... S. pakbaraensis sp. nov. (Andaman coast, Thailand)

– Notopodia without capillaries........................................................................................ S. sundarbanensis Bhowmik, Ghoshal, Salazar-Vallejo & Mandal, 2021 (River Thakuran, Sundarbans, E India)

10. Median antenna long as 3–5 times of lateral antennae, notopodial capillaries present from anterior chaetigers; pharynx with 12 marginal papillae....................................................... S. sirilukae sp. nov. (Gulf of Thailand)

– Median antenna nearly 2 times longer than lateral antennae; notopodial capillaries present from posterior chaetigers; pharynx with 14 marginal papillae....................................... S. constricta Southern, 1921 (Chilka Lake, India)